3.8 Turbo motors= Great?

[tommyguns]

Hello all, I had a 86 GN and sold it way before I got a chance to play with it. I'd like to ask, what is it about the motor that makes people say how tough it is, and how much abuse it can take?
I'd like a technical answer if I can get one. What did Buick do to make it so strong. Is it the crank, rods, pistons, block? Everything?
Thanx, I'd really like to know.

 

[BadAssGN]

I can list a few items for you

The Block was beefed up in the cylinder areas as well as in the lifter valley
The head bolt holes we recessed to prevent cracking, there is other stuff with the block I'm forgetting.

The Crank is cast but the fillets of the crank are rolled so it will handle a little flexing before it breaks.

the rods are stronger also.

the biggest drawback is the 8 bolt heads. the cars are prone to head gasket failure. you can get very good HP numbers when the package comes together just right.

HTH

 

[tommyguns]

Thanx, are the stock pistons forged? As far as the gasket failure, I assume some ARP studs could help that..

 

[XxDarkSidexX]

Hello all, I had a 86 GN and sold it way before I got a chance to play with it. I'd like to ask, what is it about the motor that makes people say how tough it is, and how much abuse it can take?
I'd like a technical answer if I can get one. What did Buick do to make it so strong. Is it the crank, rods, pistons, block? Everything?
Thanx, I'd really like to know.

I dont know what those engineers did, but its funny that the latest z06 and 911Turbo killer is a V6! Thats right, AND TO BOOT its a 3.8L, the new skyline.


-turbo (2 of them tho), 9 to 1 compression, 3.8L or 3799cc, 3800 lbs
this all sounds very very very familiar, maybe the darkside?
-15" rotors 4 piston calipers, a TRUE 2+2 seater, pulls over 1G aginst gravity,
Awd, launch control, these dont sound so familiar though.....its the new skyline.

ds

 

[novaderrik]

the Buick 231 V6 was naturally tough because, in it's old "odd fire" configuration, it tended to vibrate a lot. so they made things stronger than they really needed to be just to have the things survive so they could have a smaller engine for the midsize cars of the smog choked years of the late 70's.
when they went to the "even fire" crankshaft, the motor was smoother, so all that extra "beefiness" they built into it before wasn't needed to just allow it to live. but it was still there, and it made the little tiny 231 a really good platform to build into mass produced turbocharged terrors- it became the 3.8 that was put in the turbocharged Regals of the 80's. later on, with the inclusion of balance shafts to make it run even smoother, it made a good base to add a supercharger to- which is the 3800 that GM used right up until a couple of years ago.

 

[Turbo-Archie]

From what I have read, the 3.8 heads have a better design than a chevy small block.

Also from what I have seen, the CL of the crank on the buick is pulled up into the block above the pan rail. Where as the chevy V8 and 4.3 has the crank CL even with the pan rail. From what I understand, when the chevy turbo 4.3 guys turn up the wick, they start spitting out the cranks and have to go to the full bowtie long blocks.

I ran a full N/A long block at about 450-500HP and it never let go. It only had turbo pistons/rods installed on a n/a crank.

 

[tommyguns]

What generally is the breaking point of these turbo motors? How much power?

 

[DailyDrifter]

3.8l turbo engines=Headaches and slim wallet

But to answer your question. They are so strong because they are made of Steel and Braun

 

[Pablo]

What generally is the breaking point of these turbo motors? How much power?

Good question. Unfortunately I think a lot of the answers you'll get will lack technical data.

With the wide range of tuning skills in the Turbo Buick world I think you'll find that many people blow their engines due to a poor tune and just chalk it up as a weak point in the engine. Detonation can get by your knock sensor, and pre ignition is invisible to your knock sensor. Pre ignition will kill your engine in a hurry, and small amounts of detonation take their toll.

I've been trying to research this subject myself.. rather than throwing money at a shortblock to make it stronger I would like to know why they break. I have a gut feeling that through careful tuning a lot of it is preventable.

That said, through my own unscientific analysis of engine failure posts, it would seem to me that the main caps/bearings crank combination is what seems to go most often. This is consistent with detonation damage... so I dont know what the absolute power level is that can be attained. I think it all depends on how that power comes in. Two cars developing 600 hp can have vastly different cyl pressures depending on the RPM that the power is produced. 600 hp at 6000 rpm is imparting less downward force on the pistons than 600 hp at 5000 rpm.

If you think about it, the main thing we are dealing with is insane cylinder pressures. A lot of what N/A guys build for is to withstand a lot more RPM than the average turbo buick. If I am not mistaken, rpm kills rods and rod bolts. Cyl pressure is just a force pushing down on the rod vice rpm which is trying to extend the rod. A rod has a lot less extensional strength than compressive strength.

It's my own personal theory that you could probably build a T/R engine to withstand more horsepower if you move the rpm band up (with a bigger cam). You can develop the same HP but at less cylinder pressure. The catch is now the rpm limits of the engine but I suspect they are nowhere near as stressed as the cyl pressure limits in your average 3.8

If anyone has some insight on this, please by all means post.

 

[turbodave231]

The stock 3.8 engine is a very tough little engine, but does have its drawbacks.

Why is it strong and powerful?
Good combustion chamber design
Good flowing intake and exhaust ports
Short, compact Deep skirt block.
Short compact cranks
Superior Cast iron and castings
Great engine management (for the day)

What are the drawbacks?
Poor oil pump, aluminum housing, iron gears, too many 90 degree turns....mostly cured with the gerotor pump in later BV6's
Inadequate head clamp load....Buick history is full of headgasket issues. Solved on the Stage engines
Off set connecting rod which dictates high tension rings and a heavy full skirt piston....solved with 3800 on center block and Stage On Center blocks
Rope rear main seal......they leak!!!
Vibration.....The 90 degree V6 has natural imbalance that can only be managed not eliminated. 3800's had balance shafts to help this problem.

The amazing thing about these engines is that there are no exotic or expensive parts in the engine. Everything is cast, No premium materials, built on the same assembly line as everything else. In the right tune a stock engine can deliver 500-550RWHP and survive!! Show me a stock SBC or BBC of that era that can make that claim!!

 

[TurboBuickSix]

From what I have read, the 3.8 heads have a better design than a chevy small block.

The heads were designed and improved upon by Smokey Yunick for Buick.