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2007 Hummer H3 3.7L - Low Compression - P0300 P0171 - Engine Rebuild Thread
I recently started to notice lower (than usual) fuel economy out of my rig. When I first purchased the vehicle (about a year ago), I was able to achieve a very comfortable 16-18 mpg with 33" tires at 65-70 mph, even with a few stops (city driving) here and there. Fast forward a year, and now I am struggling to get 15-15.5, even at a measly 60-65 mph, all highway. Forget anything above 15 mpg if I up the speed to 65-70+ mph. I always run full synthetic oil in the engine (as well as in the rest of the drivetrain components), keep the air filter clean, have installed new coils/plugs, cleaned the throttle body and MAF (with CRC cleaner), and keep 40+ psi on a very mild A/T tire. All of this, combined with the manual transmission, barely averaging 15 mpg seems rather low.
Additionally, the vehicle has really seemed to lose some of it's get up and go and does not seem to have the power that it used to have when I purchased the vehicle. Even by the I5's standards, this thing is really starting to feel pretty anemic on the high end. It's not uncommon for the vehicle to run out of juice at 55-60 mph in 5th gear when going up even the smallest of inclines. To make matters worse, I recently got the dreaded P0300 (Misfire) and P0171 (Lean) CEL codes, which I was surprised to learn considering my rig is a 2007, and should theoretically be free of the valve seat issues as found in 2006 models. I ran a smoke test first to confirm that there were no leaks at the intake manifold (which there weren't), and then ran a compression test using a traditional compression psi gauge. Cylinder 5 read the highest at 175 psi (when warm), while every other cylinder only read between 135-150 psi (new engine specs call for 215 psi). I then purchased a leak-down gauge, borrowed a friends air compressor, and ran a leak-down test on all five cylinders. All five cylinders had some type of leakage at the intake valves, ranging from roughly 20% leakage on cylinder 5, to about 30-40% on the remaining four cylinders. Exhaust valves all checked out 100% okay, and there was no leakage in the head gasket. There was however, also a considerable amount of leakage in the piston rings as well; during the leak-down test, as I could hear air hissing throughout the crankcase, and actually feel it blowing through the rubber hose that connects to the plastic resonator on the engine (crankcase ventilation hose). I was willing to accept a little bit of leakage from crankcase, but this was a pretty heavy stream of air that was exiting through the resonator hose. On top of everything else, I started to get an intermittent Oil Pressure light after the engine heats up and I come to a stop at idle; the light will switch on, then as soon as I give even a mili-ounce of fuel (800-1000 rpm at idle) the light goes out. This is leading me to believe that the bearings are starting to wear out; if the oil sensor itself were bad, I would think the light would turn on permanently, not intermittently. With all this in mind; the leaking intake valves, the large leakage in the piston rings, and the oil pressure warning light, by the power invested in me, I have decided to just pull the engine and perform a complete rebuild on it. I have already purchased many of the parts required to perform the rebuild, but was going to hold off on cylinder sleeves (and the expensive specialty tools required to remove/install these), and a new crankshaft until I have the chance to measure their tolerances/condition and see if they can be reused. If anyone on here has ever rebuilt the 3.7 LLR engine, and has any knowledge/wisdom to pass, I will gladly take any help you have to offer. Despite all the evidence I've found pointing to this engine being (essentially) worn out, I am still impressed with how it runs none the less. It doesn't idle rough, doesn't knock, and still has a decent amount of power on the low-end (1-3rd gear anyways). Had it not have thrown any codes, or thrown the oil light, I could have chalked up the low power on the high end to this simply being a 5-cylinder inline engine, and I could have chalked up the low fuel mileage up to this vehicle simply "being a Hummer". It's only because of the engine codes/compression test that I was truly able to deduce that anything was wrong. As far as a budget goes, I am estimating this will cost about $3200, about $1000 of which is tools. If the cylinder sleeves are still in good condition, this should bring the cost down a decent amount. Once I am complete, I'll give a total cost of everything. I created this thread with the intent of posting my progress/lessons learned along the way, as well as some pictures for anyone in the future who wishes to rebuild their 3.7L. More to follow in the upcoming weeks/months. Hope all is well with everyone! |
I'm looking forward to hearing your progress, specifically where you run into finding certain parts. For example I know the crank and balance shafts are no longer available, but shouldn't matter considering yours should still be OK to renew or grind. I am considering a rebuild in the near future, hence my interest.
Regarding the oil pressure light - I have changed mine out twice now. Both times I have had oil in the connector, and it was acting the same as you are describing. Also tried both a Durolast and AC Delco. Both times replacing it solved my problem. I know you are rebuilding because of many more concerns than that, but I that has been my experience. |
Miles on your 2007?
You might just have crap on your Valve Seats which will not let them shut all the way to form a proper seal. Perform an Intake/valvetrain cleaning and see what happens before you head down the rebuild it trail. Noticed another thread and was wondering about HummerZ special sauce for stumbling H3 |
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Doc, approximately 145K miles on my H3.
Well, I went ahead and ran two cans of Seafoam through the engine, as well as a can of Engine Restore in the oil. I used a similar setup to Hummerz post when running the SeaFoam through the engine (dripped through the throttle body). I drove the car about two hours afterwards, and even went on a test drive to measure the mpg and was happy when I achieved right at 17 mpg. I went home, then checked the compression afterwards. The engine generally felt stronger (was able to maintain speed slightly better on the freeway than before), but I wanted to see if the compression improved. No increase. Not even a few PSI. Leakage results were roughly the same as before and Cylinder #4 actually went down a little bit :-( So at this moment I am fully committed to rebuilding the engine. I went on Facebook marketplace and was actually able to find a used 2008 3.7L for an extremely, extremely low price (less than $1000). The cheapest price I could find otherwise was $2200 online. I was going to rebuild this engine, and keep driving my car in the meantime (then do a swap once I’m finished). However, the 2008 engine only has one camshaft sensor instead of two like there is on my current vehicle. Does anybody know if it is possible to machine the 2008 head for two sensors? Additionally, would there be any other (subtle) differences between a 2007 vs a 2008 block that would otherwise prevent a bolt on installation? Worst case, I could pull the head from my current engine, rebuild the block of the 2008 engine, have my 07 head rebuild then install it on the block of the 08 engine. More to follow! |
Part #1 - Initial Cost, Donor Engine Compression Testing & Cylinder Head Removal
Cost
A few days ago I was able to acquire the donor engine and get started on this whole project. I was able to obtain this engine (a 2008 model), as well as an extra Cylinder Head for a 2007 engine for an incredibly affordable price of $420. The engine was reported as being in fairly rough condition (I understood as not running) but since I was planning on rebuilding it anyways, I wasn't too concerned about it's overall condition. With the donor engine in hand, and the remainder of the parts ordered, I have put together a budget for this entire rebuild. All prices include tax/shipping. -2008 Engine & 2007 Head = $420 -Engine Stand / Hex Sockets = $122 - Purchased at Harbor Freight (I simply chose their 1000 lb engine stand and some Pittsburgh Hex Sockets since I didn't have any). -Ferrum Tools Timing Set (EN-48464 J-44221 & EN-46547 Alternatives) - $200 -Mizumo Auto Timing Kit / Water Pump / Oil Pump set - $240 -Mizumo Auto Pistons/Main Bearings set - $300 -Parts Geek Head Gasket/Seals Set - $86 -Cylinder Head Rebuild - $700 - NOT YET complete, but I anticipate it will be somewhere in the $500-700 range. -Rock Auto Order - $450 - 5x Engine Tech connecting Rods, 1x 195F Thermostat (AC Delco), 1x AC Delco Knock Sensor, 1x set of Mahle Balance Shaft Bearings, 2x Crankshaft Oil Seals (Front & Rear), 1x Standard Motor Products VVT Solenoid/Actuator, and 1x Standard Motor Products Blue Streak Oil Pressure Sensor. Total Cost (as of now) - $2518. Rounding up and accounting for things that will inevitably go wrong, my budget will be $3000 for this entire project. Considering most of these engines go for roughly $2000-3000 online (used), if I can make this work for under $3000 I will be extremely happy. Potential Pitfalls - Needing to replace the Cylinder Sleeves: if these are bad on the donor engine, then they require specialty tools to remove/install, which will drastically increase my budget. - Balance Shafts no longer available basically....anywhere. I have 4x total (2x in the donor engine, and 2x in my current engine powering my vehicle). Hopefully I can get at least 1x solid set between the four of them, but if these don't check out, getting new/used ones is going to be extremely difficult, if not impossible without spending a fortune. Compression Testing on Donor Engine I wanted to get an idea of where this engine left off before it was removed from it's vehicle, so I first removed all the spark plugs and performed a compression leak-down test (was a moron and did not take any pictures of these, but I did perform a water test later which I did take pictures of). I was all but begging the engine to give me solid compression readings, but unfortunately that was not the case. Very similar, almost eerily similar to my current H3, each and every cylinder had approximately 40% leakage (one of which was even worse at 60% leakage) and each and every cylinder was leaking at both the intake valves as well as the piston rings/cylinders. If this engine ran at all, its power and efficiency would be much worse than ideal. Again, this is on a 2008 donor engine, which should not suffer from valve seat issues. Exhaust valves remained solid and did not leak whatsoever. Later on, once I removed the cylinder head, I poured some water down every intake port and measured the leakage at the intake valves; no surprise, there was a considerable amount of water seeping past the intake valves, confirming what I already knew on the compression leakdown test. With that, I knew I would have my work cut out for me with this engine, so I dug right in and started tearing things down. Initial Teardown (Cylinder Head Removal) I watched two very good videos (links posted below) on how to tear down these engines, so I won't rehash the entire thing here, but I will discuss some of my lessons learned. Cylinder Head Bolts - These bolts are notorious for being extremely tight, and for breaking/snapping in half. To make matters worse, GM decided to go with Hex Socket Cap Bolts, and if you aren't careful, you will strip them out quite easily. Let me be clear, you do not "want" these to break, and you should try extremely hard to do everything you can (heat, penetrating oil, tightening them ever so slightly, before loosening, etc.) to get them to break loose. That said, if they do snap, it's also not the end of the world, and I will show you how I was able to remove the broken studs. Here's my recommendations: 1. Use a punch, and some light taps with a hammer on each bolt before attempting to loosen it to try and break it loose of any rust/corrosion. 2. DO NOT use an impact wrench to try to loosen these. I have the highest end Milwaukee impact wrench, and it couldn't even make a dent in them. Additionally, all the blows from the impact wrench will loosen/widen the Hex area on the head bolts, and if you are not careful, it will become loose enough that the hex socket will strip out the bolt (ask me how I know). Just use a breaker bar instead. 3. Use a 1/2" Breaker Bar; if you need to use a 3/8" hex socket, make sure you use an impact rated 3/8" --> 1/2" adapter. A standard Craftsman adapter (non impact rated) did not hold up for me, and a Duralast Impact Rated one did not either. I ordered a BLACKROBOT 1/2"-->3/8" impact rated adapter and it's held up terrific so far. 4. Once you "feel" the bolt loosen, you will initially be met with a decent amount of resistance almost immediately afterwards. From here, I went other direction and attempted to "re-tighten" the bolt, then loosened again etc. This seemed to loosen the bolts a little more than if I did not do this technique. 5. At the end of the day, some of them will likely break, so don't get frustrated. 7/12 of the bolts broke for me. Removing Broken Head Bolts I used NEIKO 01925A Screw/Bolt Extractor kit from amazon, which includes left handed drill bits and bolt extractors. While there are probably better options out there, it was cheap and it was adequate enough for this task. I used a cordless drill just to avoid spinning the bit too fast and potentially breaking it. If the drill bit breaks when it is already lodged in the broken bolt, you will be in a world of hurt, so don't get greedy and apply too much pressure/speed to the bit. Just take your time, and you'll be fine. Once the cylinder head pressure is not applied to the bolt's threads, the threads spin almost freely. Initially, I used a punch to make an indent in the broken bolts just so the drill bit didn't run away when drilling. Be extremely careful not to let the bolt slip when initially starting to drill and damage the threads. Removing the Camshaft Bearing Cap Bolts Similar to trying to remove the Cylinder Head bolts, I would not recommend trying to remove the Camshaft Bearing Cap Bolts (the tiny 5/16" bolts that hold the camshaft in place) with anything other than a breaker bar. I initially tried to use a smaller Impact Driver with a 3/8" socket attachment, and I ruined not one, not two, but three 5/16" sockets; the bolts are much tighter than you might think for such a small 5/'16" bolt, but the impact driver's strikes caused the (very small) 5/16" sockets to crack, which caused the driver to spin and strip out one of my bolts. Initially, after losing three sockets, I found a fourth one, and just remembered to use my head, and use a breaker bar. I used a 1/2" breaker bar, with a 3/8" impact adapter, then to a 1/4" adapter to the 5/16" socket. With this setup, the bolts came loose like a hot knife through butter. Engine Condition As mentioned above, all the intake valves were leaking during the compression leak-down test, and the water test, but what about the cylinder walls? Surprisingly enough, the cylinder sleeves in the block actually looked pretty solid! My phone did not take very good pictures of these, and it's a little tough to see their condition with the flash,, but there is absolutely no scoring/abnormal marks on the sleeves. The cross-hatch patterns looked okay with the naked eye as far as I could see. I'm fairly confident with a new set of Pistons & Rings that there will be very little leak-down/blow by in the cylinder walls. The truth will come out when I get the engine back together and rebuilt and can run another leak down test with the new piston rings installed. Additionally, I was also pleased to see that there were no metal bits on the cylinder head after removing the valve cover, and the camshafts themselves looked to be in very good condition. I'll inspect these in more detail at a later time, but at first glance they definitely seemed reusable. But the carbon buildup.....yikes! So much carbon everywhere. I'll definitely have my work cutout for me when trying to clean this bad boy out. Next Time Tomorrow I plan on removing the oil pan, front and rear timing covers, and will start disassembling the bottom end. In a few days, I'll report back with any findings. If anyone would like more pictures, please feel free to DM me. I had to consolidate most of them due to the 20 photo limit, but I have plenty more available. https://cimg7.ibsrv.net/gimg/www.hum...0f352a1965.jpg Here it is! 2008 GM 3.7L I-5 Donor Engine loaded into my tried and true 1993 Jeep ZJ. Not bad for $420! https://cimg8.ibsrv.net/gimg/www.hum...f0e999d4e3.jpg https://cimg1.ibsrv.net/gimg/www.hum...f9ce0ec8d0.jpg Valve Cover Removed https://cimg3.ibsrv.net/gimg/www.hum...7462281825.jpg Lot of carbon buildup on the VVT sprocket. https://cimg6.ibsrv.net/gimg/www.hum...1f7f23b7f8.jpg Camshafts appear to be in good condition! A win! https://cimg0.ibsrv.net/gimg/www.hum...527acaf1a5.jpg https://cimg1.ibsrv.net/gimg/www.hum...4927767894.jpg For these bolts that hold down the camshafts, recommend not using an impact wrench or an impact driver. Use a breaker bar as to not strip out the bolts. https://cimg2.ibsrv.net/gimg/www.hum...2f501d3888.jpg Don't forget about these little guys when removing the cylinder head! They're smaller than the normal sized head bolt, and are located near the front of the engine (near the timing chain). https://cimg4.ibsrv.net/gimg/www.hum...57dae85bf0.jpg If these plastic caps strip out like they did for me, you can use either a pair of pliers like this. https://cimg5.ibsrv.net/gimg/www.hum...7543f5c8f9.jpg or like this. Take great care not to gouge the cylinder head. https://cimg0.ibsrv.net/gimg/www.hum...76229016f2.jpg Out of the 12 head bolts, only 5/12 of them survived. Hey, that is still 0.4166, which is at least a better average than most MLB players batting averages :-D https://cimg1.ibsrv.net/gimg/www.hum...03ba5c832d.jpg This is the kit I used to remove the broke studs. Not the best, not the worst. But it works, and it's cheap! https://cimg2.ibsrv.net/gimg/www.hum...aeffb40d5c.jpg Start out a punch, then with a #2 drill bit (from the kit), then work up to a #3 drill bit. Be careful not to drop (too much) metal in the cooling passages. https://cimg4.ibsrv.net/gimg/www.hum...24d95aa00d.jpg If the dowel pin gets in your way, removing the broken stud can be a little tricky, but still doable. https://cimg5.ibsrv.net/gimg/www.hum...b9103754af.jpg Great Success! Got them all out! https://cimg7.ibsrv.net/gimg/www.hum...15f3ec306c.jpg Head off, broken studs removed. First glance, lot of carbon build up in the pistons. https://cimg1.ibsrv.net/gimg/www.hum...1132363c0d.jpg Cylinder walls look okay! Might be able to get away with re-using these. https://cimg4.ibsrv.net/gimg/www.hum...6d91b0f147.jpg Water Leakdown Test - LOT of water draining from the intake valves. Adds another layer of confidence to the compression-leakdown test. Media/Misc. |
Phenomenal write up. Really appreciate the detail. And nice job as well!
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Agreed, Thumbs up, way uP!:D
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Part 2 - The Good, The Bad, The Ugly & the Uglier....
Updates to Budget: Previous Total = $2518 Wal Mart Run (Parts Cleaners / Misc) - $40 Piston Ring Compressor / Dial Bore / 3-4” Micrometer - $102 Connecting Rod Bolts / Crankshaft Main Bearing Bolts - $165 (Rock Auto) Cheater Bar & Impact Socket Set - $50 Balance Shaft Repair - $55 Camshaft Bearing Removal/Installation Tool - $85 Cylinder Sleeves - $200 Cylinder Sleeve Install Tool - $600 New Total = $3815 And just like that, I’m over budget. Lessons Learned: 1) When mounting the engine on the engine stand, pay close attention and do not use the mounting holes that are attached to the oil pan. If you do so, as soon as you unbolt the oil pan, the oil pan will separate from the engine, and the engine will only be held up by 2x bolts on the engine stand. 2) In order to fully remove the crankshaft and the 2x balance shafts for inspection, the rear timing cover plate must be removed, but cannot be removed while the engine is still on the engine stand. That is, you’ll need some other type of work bench/table to set the engine block on, then remove it from the engine stand, in order to remove the rear timing cover. 3) Balance Shafts are VERY delicate. More on this in the later section. 4) Cylinder Sleeves - After closer inspection of the sleeves in this engine, unfortunately I will be unable to use them and they will need removed and replaced. Buying the “proper” tool for this (Kent Moore EN-45680-400/450) is not cheap. 5. Balance Shaft Bearings call for another expensive tool for removing/replacing them (Kent Moore EN 44225). The cheapest I could find is $800; that said, I can probably manage with a much cheaper $85 Camshaft Bearing removal/installation tool from Amazon. Progress Cylinder Head - I have successfully gotten the Cylinder Head to it’s repair shop for a complete rebuild. Water Pump - remove all the bolts holding it in place. One of my bolts broke (go figure); in order to remove it I drilled with the #2 drill bit (same kit as before), then used the #3 bolt extractor and got it out. Harmonic Balancer Bolt - This was the first major roadblock I hit in this project. This sucker is TIGHT! In order to get ANY torque on this stubborn bolt, you’ll need to jam something against the connecting rods or crankshaft weights so the engine will not spin. I used some pieces of wood, and jammed it against the connecting rods, which held the engine in place nicely. I would strongly discourage anyone from using any hard pieces of metal to hold the engine in place; wood worked just fine for me. Use a 15/16" impact rated socket. 24mm is just a bit too loose for such a high torque application. I first tried the impact wrench, which didn’t loosen the bolt whatsoever. This was with one of the strongest Milwaukee Impact Wrenches on the market, on the highest setting, with a fully charged battery. I tried a 24-inch 1/2” Breaker Bar and put every ounce of strength I had into it. 200-300 lbs of force, pressing straight down on it. 400-600 ft-lbs of torque, but the breaker bar did nothing at all; absolutely nothing. I eventually took a break, then decided to go get a 36" cheater bar from Lowes. I taped the steel pipe about 1/2 down the 24” breaker bar, then took it a step further and put tape over the breaker bar 1/2” drive (in case it exploded, I didn’t want debris flying all over the place), and even wore gloves and eye glasses for the same reason. Here we go: round #3 with this bolt. With the pipe about 1/2 down the breaker bar, that meant there was about 3-4 feet of leverage (compared to 2’ originally). Roughly 600-800 ft-lbs of torque. I put every ounce of strength I had into the cheater bar, and I was sure the 1/2” drive was going to explode at one point. FINALLY, I heard.........a distinct “click”, followed by an ever so small amount of movement. I kept the force applied. I felt more movement, then.....smooth motion? Surely I had stripped the bolt head... Nope...all there, and I could finally start truly loosening the bolt without fighting for my life. And eventually, I got it off. Mission Accomplished. Bolt Removed. Harmonic Balancer Removal But what about removing the balancer itself? If you have a Harmonic Balancer remover, then life should be fairly easy. If you don’t have one like me, this is how I removed it using a slide hammer kit. I purchased a Maddox Slider Hammer Kit from Harbor Freight about 6 months ago for rebuilding a Jeep axle. It has a “3-claw” option for the slide hammer as well, so with a little improvisation, I made a jerry rigged harmonic balancer remover (see pictures). Fortunately, this was not nearly as difficult as removing the bolt, and the balancer came right off. And there was absolutely no damage to the face of the crankshaft More great success! Small victories! Onward! Setting the Engine on the Work Bench - You’ll need to do this in order to remove the rear timing cover (as previously mentioned). Put the engine on a work bench, disconnect it from the engine stand, and remove the rear timing cover. Removing the Balance Shaft Timing Chain Tensioner/Chain - Remove all the required bolts, then remove the timing cover. This will allow you to access the balance shafts, tensioner, and chain. To remove the crankshaft, you will first need to remove the balance shaft chain. To loosen the chain up, start with removing the balance shaft chain tensioner. If you did not remove the crankshaft main bearing caps, then the crankshaft should be tight against the engine block, and the timing chain should be able to be removed by this point. If you did loosen the main bearing caps first, then you’ll find that removing the balance shaft timing chain tensioner by itself is not enough to remove the chain. There will be more tension on the chain at this point, because the crankshaft will be “looser” and will droop towards the bottom of the engine block, which puts tension on the chain. If this is the case, the way I removed the chain was to get a rubber mallet, and give the crankshaft a few whacks with one hand, then take your other hand and try to to remove the chain from the crankshaft gear (at the same time). Eventually, with enough whacks, you will feel the chain loosen up enough that it can be removed. Your other option is to re-install the main bearing caps & brace, tighten, and the remove the balance shaft chain. Regardless, it was more difficult that I originally envisioned. Balance Shafts As mentioned previously, these balance shafts are extremely delicate; DO NOT even think of trying to pry them out on the “metal” flange attached to each one, where the bolts tighten them to the engine block). While I originally envisioned this section of the balance shafts being made out of steel (which bends before it snaps), these are made out of a cheap cast material that appears to have sand as one of the main ingredients. This flange section of this part is extremely, extremely brittle, and I originally chose to try to pry out the balance shaft on this section. I put a pry bar up between the flange and the engine block, and with a tiny, tiny ounce of strength applied, this section of the balance shaft snapped right off. Considering this material is designed to mount the balance shaft to the engine block and prevent it from backing out, it has almost zero strength whatsoever, and I almost don’t trust it for that one simple task. So instead of prying out the shafts at this location, pry them out by the balance shaft gear itself, Now I faced a problem: how do I reattach this broken piece to the balance shaft? I almost convinced myself that I could get away with JB weld, until I took a break, drank some water, got some rest, and started to think logically again by reminding myself that this is going into a Car Engine, and that I will not take chances on something like this (what if it failed while my wife was driving and caused a catastrophic failure?) So I started calling welders in my local area to see if it could be welded back together; as it was, not a single welder in my town believed that delicate of a material could be welded back together. So now my only options are to 1) get another balance shaft (extremely expensive on ebay) or 2) try to disassemble the balance shaft and replace the broken part on my current balance shaft. So now it came down to seeing if I could remove the bolt and gear from the (driver's side) balance shaft. I was able to use an allen key to prevent this piece from spinning on the shaft, then I used some channel locks to grip it and hold it into place while I applied torque to the bolt. The impact wrench was unable to loosen the bolt, so I tried a breaker bar. After a few attempts at getting the bolt to move, the bolt eventually snapped. So out came the bolt extractor set, again. I first tried the #2 left handed drill bit, then I was once again able to pound the #3 bolt extractor into the hole, and managed to get the bolt to move. But something was wrong; when trying to loosen the broken bolt stud, it was going deeper into the balance shaft, not coming out. Then it occurred to me, it is a “lefty tighty" bolt; that is why the impact didn’t remove it, and the bolt broke. Seriously, did GM actually try to make this the most poorly constructed, overly complicated piece on this entire engine? Then discontinue it so you have to work extra hard to try and find a replacement, all while saying in the factory service manual that you should not “disassemble the shaft assembly” if you want to repair it? Sorry, rant over. I tried to figure out why they would have chose the bolt to be a righty-loosey bolt, and I think it came down to the direction of engine rotation. If you’re looking at the rear of the engine, the engine spins counter clockwise, as do both of the balance shaft gears. If this were a “lefty-loosey” bolt, there is a chance this counter-clockwise rotation could loosen the bolt, and cause the gear work it's way loose. Because the passenger side balance shaft gear (not the shaft itself) spins counter clockwise as well, I’d be willing to bet that it is a “righty-loosey” design as well (did not put this theory to the test). Regardless, I eventually got the broken bolt out using standard right handed drill bits, since the bolt extractors were designed for lefty-loosey bolts; I got there eventually, but wow what a pain that turned out to be. Now I could truly focus on the real problem at hand. Before removing the bolt and the (driver side) balance shaft gear, I took note of where the timing marks were in relation to the shaft, and even made a mark on the shaft itself just in case there was not a “key” or fitment when re-installing the gear. Once I got the gear off, I noticed there was a notch in both the gear and the shaft itself, meaning the gear could only be reinstalled one way. I then tried to use a bearing puller to remove the sand-cast-bearing-thingy from the shaft itself; low and behold it came off! So now I just needed to find the part online and get it replaced. While I couldn’t find a simple replacement, I was able to find a balance shaft for a 2.8L I4 GM engine that appears to use the same exact piece on it's balance shaft. Better yet, this shaft was brand new, vice used; I figured I could use the flange piece, as well as the gear, and the bolt from this balance shaft. Not bad for $50! BOTTOM LINE; had I been more careful with my balance shaft, I would not be in this mess to begin with. That said, the material that holds the balance shaft to the engine block is extremely delicate and brittle; if this flange piece decides to break off of your balance shaft, there is no way to weld it and you could potentially be in a world of hurt. The GOOD news, once I removed the passenger side balance shaft, and inspected them both, the shafts themselves are both in great condition! There are no cracks, no scuffs, and no damage to the bearing surfaces. I can absolutely reuse these! Onward to the cylinder bores; remove the crankshaft, connecting rods, and pistons (from the top of the engine, not the bottom). Main Bearing Brace Bolts - These are tight, but doable. A 24” breaker bar worked for these, then once loose, an impact driver was used to remove them the rest of the way. Unfortunately, these are “torque to yield” bolts and they cannot be reused. To make matters worse, on Rock Auto they are ~$36 for a pack of 10, and unfortunately you need 12. Get ready to spend $72 on bolts! Once you get all the bolts out, go ahead and remove the bearing brace and set it aside. Make note that during re-installation, the direction matters, so make sure you install it exactly the same way you removed it. Fortunately, you’ll find the words “REAR” engraved on it to make it easy for you. Cylinder Bore Inspection I purchased a $50 dial bore gauge from Amazon with a 0.0005” tolerance with decent reviews. According to the Schwartz manual for the 3.7L engine, the tolerance for these bores is 3.7623 - 3.7629”. In theory, a 0.0005” would not have an accurate enough measurement for this engine, but I figured I could start at 3.7626” (right in the middle), and with a 0.0005” tolerance gauge, one “tick” mark would put you at 3.7621” or 3.7631”.. If the bore is +/- one tick mark away, that is still extremely close to tolerance, and I figured I could use a magnifying glass to get a closer inspection if able. If the test came out to be outside of 0.0005”, regardless of how expensive of gauge I’m using, that would mean the engine’s cylinder sleeves would be out of tolerance and would ultimately need replaced. I grabbed my bore gauge, calibrated it with the help of some 3-4" micrometers, and went to work; before I even got the gauge into the cylinders, it became apparent very quickly that these cylinder sleeves could not be reused. After closer inspection, it was evident that this engine suffered from oil starvation at some point; enough that the cylinder sleeves themselves suffered from a pretty decent amount of scoring, especially on the thrust sides of cylinder walls. Looking at the pistons revealed the same thing; plenty of carbon build up on the pistons except on the thrust sides where they were a lot more shiny due to scoring. This explains why the compression was suffering when I performed the leak-down test; not only were the intake valves leaking, but so were the piston rings/cylinders. After examining them, it is very clear why. I did eventually perform a dial-bore inspection of the cylinders just for the heck of it; the frustrating part is that every cylinder near TDC passed the inspection, and was essentially right at 3.7926" (right in the middle of the specific tolerance). However the lower you went, the more the cylinders went out of tolerance due to the scoring. Had this engine not been starved of oil, I get the feeling the cylinders would have held up just fine. Main Bearings Inspection - More signs of low oil/oil starvation, especially on cylinder #3, which the bearing was actually pitted pretty badly. Wrapping Up This Section - It is very clear that this engine was in much, much worse condition than I originally thought and is going to cost more than I anticipated. That said, I believe there are several silver linings to this project. For one, I think it because the engine is in such poor shape, it will make it all the more rewarding when I finish rebuilding this engine and bring it back to life Additionally, this whole thing gives me a whole new level of respect to those who rebuild automotive engines for a living. As far as budget goes, obviously this is less than ideal, but the reality is, a decent amount of my $3800 is tools (roughly $1200). Additionally I purchased this donor engine so I could specifically keep driving my vehicle in the mean time (cost $420 as it was, and was 100% not necessary, as I could have just removed the engine actually in my vehicle). Taking all of this into account, only about $2100 has been spent on parts that are actually dedicated to the engine itself. And don’t forget about the power of knowledge and experience as well; regardless of how much I end up spending on this, this project has forced me to research many different topics on automotive engines, and the knowledge I've gained, as well as the actual hands on experience with this engine, I do think is invaluable in some ways. Not to mention that I can now be confident (when the engine is back in one piece) that it was put back together 100% correctly, and no shortcuts were taken. Next Time I will be away in California for work for roughly three weeks, so my next post won’t be for almost a month. When I get back home, my big focus will be installing new cylinder sleeves, as well as the balance shaft bearings. The tool required for the balance shaft bearings is extremely expensive, but I am pretty confident I will be able to get away with a much cheaper universal $85 Camshaft Bearing tool from Amazon. Fingers crossed I will not have to eat the cost of another extremely expensive tool to install the balance shaft bearings. Thank you so much for reading (if you got this far) and I’ll report back here in about 3-4 weeks! https://cimg2.ibsrv.net/gimg/www.hum...3b6b8f43ff.jpg Water Pump Housing - Looks clean! https://cimg3.ibsrv.net/gimg/www.hum...8b245cac03.jpg https://cimg4.ibsrv.net/gimg/www.hum...59f593b1cc.jpg Broken Water Pump Bolt - use a #2 left handed drill bit (from my kit listed previously) then the #3 bolt extractor and you will get this little guy out. https://cimg5.ibsrv.net/gimg/www.hum...efb0581b8a.jpg Draining the old oil. Look how nasty that stuff looks! LOOK AT THAT! https://cimg6.ibsrv.net/gimg/www.hum...320cb0fe0d.jpg https://cimg7.ibsrv.net/gimg/www.hum...c474ecdf0b.jpg Before removing the oil pan, ensure that the engine mount is NOT attached to any of the threads that are attached to the oil pan. Otherwise, when you remove the oil pan, bad things will happen. https://cimg8.ibsrv.net/gimg/www.hum...f164903b72.jpg See how these are not attached to the oil pan? This will work! https://cimg9.ibsrv.net/gimg/www.hum...f8f0e60c55.jpg https://cimg0.ibsrv.net/gimg/www.hum...3164e92d13.jpg https://cimg1.ibsrv.net/gimg/www.hum...d535d8b38a.jpg Hard to believe that this was once used to contain oil. Gross stuff. https://cimg2.ibsrv.net/gimg/www.hum...fd426da492.jpg https://cimg3.ibsrv.net/gimg/www.hum...5b911727c7.jpg Harmonic Balancer Bolt - The tightest bolt I've ever encountered as a DIY'er. https://cimg4.ibsrv.net/gimg/www.hum...df9c2c5fdb.jpg Wedging wood up against the crankshaft to hold it in place. https://cimg5.ibsrv.net/gimg/www.hum...4f09038a33.jpg Then slide it down in deeper. https://cimg6.ibsrv.net/gimg/www.hum...673e12a853.jpg Tape (as protection) in case the breaker bar drive decided to explode on me. https://cimg7.ibsrv.net/gimg/www.hum...917da98a30.jpg https://cimg8.ibsrv.net/gimg/www.hum...3b1dec9ed1.jpg This is the setup I used to remove this stubborn bolt. Wow! https://cimg9.ibsrv.net/gimg/www.hum...c15be18f55.jpg https://cimg2.ibsrv.net/gimg/www.hum...2791b36c90.jpg Great Success! Look at the size of that thing! Unfortunately, I've had trouble obtaining a new one. Looks like I'll have to reuse this one. |
Pictures To Part #2
https://cimg8.ibsrv.net/gimg/www.hum...88da3a2995.jpg
Bearing Caps: Pay Attention to the number, as well as the direction of which way to install them. The arrow is pointing towards the FRONT of the engine. https://cimg9.ibsrv.net/gimg/www.hum...858fd6d271.jpg Bearing Caps: Pay Attention to the number, as well as the direction of which way to install them. The arrow is pointing towards the FRONT of the engine. https://cimg1.ibsrv.net/gimg/www.hum...41b1c096c0.jpg Bearing Caps: Pay Attention to the number, as well as the direction of which way to install them. The arrow is pointing towards the FRONT of the engine. https://cimg2.ibsrv.net/gimg/www.hum...5a86715c0a.jpg Bearing Caps: Pay Attention to the number, as well as the direction of which way to install them. The arrow is pointing towards the FRONT of the engine. https://cimg3.ibsrv.net/gimg/www.hum...dcd376770c.jpg Bearing Caps: Pay Attention to the number, as well as the direction of which way to install them. The arrow is pointing towards the FRONT of the engine. https://cimg4.ibsrv.net/gimg/www.hum...26cae30c2c.jpg Bearing Caps: Pay Attention to the number, as well as the direction of which way to install them. The arrow is pointing towards the FRONT of the engine. https://cimg6.ibsrv.net/gimg/www.hum...646f384199.jpg Maddox Puller (used the claws to remove the harmonic balancer) https://cimg7.ibsrv.net/gimg/www.hum...155903c738.jpg https://cimg8.ibsrv.net/gimg/www.hum...d5885cf7b2.jpg Socket Assembly https://cimg0.ibsrv.net/gimg/www.hum...7518f4028c.jpg Does it work? https://cimg1.ibsrv.net/gimg/www.hum...259bb94f11.jpg Hoorah! It works! https://cimg2.ibsrv.net/gimg/www.hum...ff7c14a1e3.jpg No damage to the crankshaft from the socket! https://cimg3.ibsrv.net/gimg/www.hum...1f4d9ddade.jpg https://cimg5.ibsrv.net/gimg/www.hum...7ed31a939e.jpg Bearing brace! Recommend not removing this until AFTER removing the rear timing cover, balance shaft chain, and the balance shafts. By keeping this installed, it helps keep the crankshaft tight, which helps to loosen the balance shaft chain. https://cimg6.ibsrv.net/gimg/www.hum...d55c4b9e15.jpg https://cimg8.ibsrv.net/gimg/www.hum...349cf1a7a0.jpg "REAR" indications on the bearing brace. https://cimg0.ibsrv.net/gimg/www.hum...601490c90d.jpg https://cimg1.ibsrv.net/gimg/www.hum...891895566c.jpg On the front timing cover, these two bolts are longer than the rest. https://cimg2.ibsrv.net/gimg/www.hum...8854fe7ccc.jpg Good pry location for the front timing cover https://cimg4.ibsrv.net/gimg/www.hum...2f241888c8.jpg More grossness! What the heck kind of oil did this person run in this engine? |
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