109 blocks

[driveshaft man]

are there any donor cars that have the 109 block ? or is there enough difference in a 109 vs any 3.8 put in various cars in the 80s.
Harold

 

[turbo nasty]

All the 86 and 87 3.8 NA have the same block just DO NOT have the turbo oil drain provision.
Some folks drill the hole others just run it to the oil pan.

 

[87GNSteve]

The Gbody cars of late 86 and 87 Regal, Cutlass, Grand Prix, 3.8 carb cars have the 109 block. Just have to drill the hole for the turbo drain.
These cars arent supposed to have the turbo* cranks but the one I pulled from an 87 Regal had STD/STd Gm bearings w/ a turbo* crank.

*Turbo crank is where both rod and main journals have fillets.

 

["More Boost"]

All the 86 and 87 3.8 NA have the same block just DO NOT have the turbo oil drain provision.
Some folks drill the hole others just run it to the oil pan.

i was talking to my machinist about running the turbo oil drain in the pan, and he said under hard boost it might be possible due to crankcase pressure, might hamper (or impede) oil flow from turbo. i mean cc pressure actually trying to push the oil back up the drain tube, or at least put some pressure on the flow. anyone have any info on this?

 

["More Boost"]

also i could save the 60 bucks or so for a factory buick oil drain tube, if i drilled the block. i'm building a 4.1 that of course has no provision for oil drain back. as u see i'm undecided on what to do.

 

[Nick Micale]

i was talking to my machinist about running the turbo oil drain in the pan, and he said under hard boost it might be possible due to crankcase pressure, might hamper (or impede) oil flow from turbo. i mean cc pressure actually trying to push the oil back up the drain tube, or at least put some pressure on the flow. anyone have any info on this?

Why would the CC pressure be any different than in the valley area where the stock drainback is located?

Cars I know of that drain the turbo oil to the pan have run for years w/o any issues.

Welding a bung in the pan plus hose and fitting will cost more than $60.

 

[S2V6RACER]

I agree the pan is the "BEST" place to dump the oil. If you have enough pressure in the crankcase to stop the draining, you have bigger worries

 

[driveshaft man]

With oil pressure at 40 plus pounds anytime boost is present, a little crankcase postive pressure(which cannot be more than boost pressure if rings were not sealing at all) should not be an issue for oil return , no matter where it is located.

 

[87granny]

you can return oil back into the pan there are turbo cars out now that have the drain back set up that way just look at any turbo vw passat 1.8

 

["More Boost"]

i had a 91 mustang 5.0 with a supercharger that i ran the oil drain to the pan, but i was only running 12psi boost. never had a problem, but i didnt know about the extra boost my buick produces. i would rather run into pan than drill a 1/2" hole in the front of the block (4.1). i appreciate everyones input.

 

[GNX-RX7]

new to turbo buicks why do people use the 109 blocks?

 

["More Boost"]

new to turbo buicks why do people use the 109 blocks?

they are probably the strongest stock production blocks out there (3.8)

 

[KrisW]

Not new to Buicks but new to 109 blocks and turbos...

Where all did 109 Blocks come from? I see 86/87 G-body; I assume that means 89 Turbo Trans Am, too, but is that it?

What about the other 3.8 blocks? Are there any to stay away from?

 

[rw87tt]

The turbo blocks casting numbers are 25526109 located on the bottom drivers side of the block. It has the turbo oil return boss in front of the block if not used in a turbo application. The oil return holes in the lifter valley are drilled. Compared to the standard 3.8 it appears to be alot stronger there. The oil pan is a twenty bolt. Look for the twenty bolt pan or the oil return boss and take it from there. The twenty bolt pan is pointed in the front. The turbo cranks are found on the 4.1. if it still has the original. The crank has to be rolled on both the mains and jornals to be a turbo crank. Rumor has it that the good wrench 3.8 was a turbo motor except for maybe the pistons.

 

[Lynn D. Brown]

3.8 blocks

Yes, the '86-'87 blocks are all the same except 4 the hole, however the earlier ones, and I know the '84's are this way, have a little different lifter valley. It looks a little weaker.