For the life of me, I cannot figure out why GM decided to install the 3.5 and then the 3.7 L engines in the H3. Yes, I know they were in the Canyon and Colorado trucks...but, those trucks would have also been stronger with the 4.2L (291 hp & 277 lb-ft of torque) engine! They had already proven that engine in their Trailblazer!
Anyone have an insight on this totally unimportant question ❓

 

The 4.2L is too long to fit in a H3/H3T/Colly/Canyon.

 

Thanks Doc! I wondered about that but I thought, surely GM engineers would simply use the same frame (upgraded) as the Trailblazer and make it fit...not rocket science. If they had done that, they would have saved GM a lot of COSTS! It would have increased the power to weight ratio, improved performance, increased towing capacity and payload! It would have been an improvement in many factors as well as improved PROFITS! I know that the Trailblazer suspension sucked, but the Buick version was stout! Just thought it was interesting to contemplate. Thanks for your response! Happy Trails to you!

 

The were in a joint venture with Isuzu to develop and utilize the Atlas I5 in their smaller/mid-size trucks. The idea being 5 cylinders makes more power than a 4, and is more economical that a 6. The GMT 355 (Colly/Canyon/ i-350 & i-370) and 345 (H3) were all specifically made to use the I5 3.5 then 3.7 variants. The problem is that H3s are heavier than the GMT 355s and that taxed the I5s making many who do/did not understand what a straight block does best complaint about performance. Truth is, the I5s make a bunch of TQ down low for an excellent off road truck type use. Not so much a high winding HP machine for out on the open road.

 

That was around the time when GM "stole" the design of Isuzu's diesel. That sentence may upset some rabid GM owners, but what the heck.

 

Thanks to all the TREE HUGGERS there are>> landmark fuel economy standards The Chevy TB had a lower curb weight, with the LL8 installed, kept the mpg at/above standard at the time.
My LLR works great for me!

Remembering the Only Five-Cylinder That Was Mass-Produced in the U.S.

 

Than you, Hummerz. Interesting article about the evolution of the I-5 used in the H3 Hummer. The GM BelAir concept car looked amazingly like the Ford Thunderbird, don't you think?
Anyway, I figure that if I maintain everything as I should, this H3 will be a strong performer for many years.

 

There was a prototype of the I6 in an H3. It did not have a mechanical fan or shroud. All electric.
It was at a local salvage yard being parted out. I have a photo somewhere.

 

The H3 does not have a reliable transmission. I5 breaks the drive and transmission (in hard mud). If there is I6, then it is necessary to change the entire transmission.
Also if do a swap for more powerful and reliable engines, but need also change the transmission. Otherwise there is no point.

 

I didn't intend to underline my earlier post!
Tainter: That's an interesting post about the I-6 prototype.
Diesel: I'm not sure if I agree that the I-5 transmission is not reliable. In my experience, most transmission issues were caused by poor maintenance and improper use. Jeep owners have similar issues.
Just my opinion and worth exactly what you are paying me for it. It's all good fun.