are their internal differences between hot air and IC?

[turbobuick1]

This subject has probably been beat to death, but I'm inquiring if there are internal differences (rods, crank, pistons, rings, rocker and ratios, etc.) between the 84/85 Hot Air blocks and the 86/87 Intercooled?

The reason I'm asking is I'm looking into converting a Hot Air motor into an intercooled.

I'm aware of the turbo drain hole that needs to be drilled, obviously the intake and the turbo plumbing, is there anything else I'm missing? Maybe something I haven't considered?

I appreciate anyones help, I'm sort of a buick newbie and trying to gather knowledge from the more experienced

 

[kenny]

14 bolt oil pan vs 20 bolt

Other than that, no

 

[stagemonster]

some 85 hot airs have the 109 with 20 bolt pan. The internals should be the same.

 

[Quick6'n'-K.C.]

14 bolt oil pan vs 20 bolt

Other than that, no

WRONG!
The early hot air motors had the 3 dot rods, i just pulled one and it had the 14 bolt pan, 2 bolt for the timing cover, and 3 dot rods (they are weaker than the 2 dot)
It should have the rolled fillet crank, and good turbo pistons.

I would do it, but i would keep the horse to around ta49 with 22-23psi of boost, sort of around 400-430 horses for it to be safe and reliable.

I do have a hotair motor ready for rebuild, i went ahead and drilled the block, but if you want to, just pull the oil pan off, and weld a return bung on it and make a return hose from a hyd shop. That or return it in the timing cover.

What are your goals with the motor?
BW

 

[Quick6'n'-K.C.]

If it is a late 85 and has the 2 dot rods, then turn that baby up

BW

 

[turbobuick1]

Great info!

I plan on building a near stock engine, very mild. The idea is CHEAP. The engine I have is an 84. So what I'm gathering is, the difference lies in lack of a turbo oil return hole, weaker rods than the 86/87 (cept for some 85s), and a 14 bolt oil pan.

Are all these blocks 109s? I would think they are. And the pistons are the same?

 

[stagemonster]

no 109s were not produced till late 1985. all 109s have a 20 bolt pan

 

[kenny]

If it is a late 85 and has the 2 dot rods, then turn that baby up

BW

How much weaker are the 3 dots? Mid 11s in a ~3400lbs car going to kill a set?

 

[Quick6'n'-K.C.]

How much weaker are the 3 dots? Mid 11s in a ~3400lbs car going to kill a set?

They are alot thinner and skinnier near the ends from what i remember.
I have a set in a box here, lemme see if i can upload some pics tonight
BW

 

[Lee Thompson]

block

Mid or late 85 they went to a 20 bolt pan--no 109 blocks untill 86 and then they lowered the deck height enough to make up for the .060 composite gasket as compared to the steel shim 85 .018 gasket.

 

[bison]

Id use the 2 dot rods. They are cheap enough and plentiful, The pistons in the 84-85 engines are a little heavier than the later ones. Theres nothing too cheap about anything that has to do with performance. Cheap, fast, reliable. Pick 2:biggrin:

 

[kenny]

They are alot thinner and skinnier near the ends from what i remember.
I have a set in a box here, lemme see if i can upload some pics tonight
BW

I'm only asking because I have a $500 hot air motor I plan to beat on. I didn't know about the rod differences, but I haven't looked to see if they are 2 or 3 dot.

Either way, I'm probably running them. I have a spare motor so I don't care so much. :biggrin:

 

[Quick6'n'-K.C.]

I'm only asking because I have a $500 hot air motor I plan to beat on. I didn't know about the rod differences, but I haven't looked to see if they are 2 or 3 dot.

Either way, I'm probably running them. I have a spare motor so I don't care so much. :biggrin:

Well, they are turbo rods LOL.... I too have a hotair motor, might use it down the road im not sure. I tore it down to a block and got the hole drilled for the oil return. Went to buy rings for it and napa wanted 100.00 for them. I thought that was out of line.
Its on the back burner for the moment.

BW