GM 3800 turbo build........

[rewguy]

what rod/main clearances/oil would you run in such a build.....? 25 lbs max boost, daily drives w 15 max. .0025 mains, .0020 rods w 10w40? sound reasonable?

[KnightEngines]

Bit more for a boosted moo.
.003 & .0025

[BlackoutSteve]

The same you'd run in any engine. 0.001" per inch of diameter,
I'd use a 5W30 as per the factory recomendation.

[mag2555]

Rod's .002", mains with cast crank .0025" with a steel crank .003"

[2seater]

What generation 3800? They aren't a Chevy V8 and will want tighter clearances than the common rule of thumb. Short crank and very high torque from low rpm, plus not a high rpm engine. Just my $0.02 but something closer to 1.5 on the mains and .02 on the rods if mostly street driven. I suggest asking/looking on the turbo Buick forums. Valve margins are also something to ask about.

[user-612937456]

I suggest asking/looking on the turbo Buick forums. Valve margins are also something to ask about.

Yea I'd listen to this guy after all there aren't many engine experts on this forum lol

[rfoll]

These engines were available in supercharged form from the factory, the stock specs might be a good place to look.

[The Radius Kid]

what rod/main clearances/oil would you run in such a build.....? 25 lbs max boost, daily drives w 15 max. .0025 mains, .0020 rods w 10w40? sound reasonable?

The engines are not the the same animal as most V8's.
I would suggest starting here:

http://www.turbobuick.com/forums/

[amc fan]

M.0025-R.0025... you should open up the oil feed holes on the mains that had 1/4" holes to 3/8". Line hone mains with heads,and gaskets on and torqued! most guys don't run them over 6000 rpm we shift ours at 5800 rpm... We went with Jim Ruggles oil recommendations on cam bearings to increase oil pressure....IE the two center cam bearings get a .080" hole and the rear gets .060".... open the oil pick up hole to .500" and make sure timing cover holes are opened up to block sizes. drill main bearing shells 1 & 4 to 7/32" and number two to 1/4" and number three to 19/64" we did this and have nice oil pressure . This was done on a 1986 Buick Regal block .The oil mods were taken from Jim Ruggles Buick V6 performance Guide.

[Alan Roehrich]

Again, Series I or Series II? Neither are the same as the older Grand National and T-Type engine, which was barely evolved over the original design from the sixties. Do not try to use old style techniques and specs on a Series II engine.

The Series II was available supercharged in FWD applications. Yes, those specs would be a start, but not the end all, for a turbocharged version, especially if the power level was significantly higher.

[amc fan]

Alan Rewguy did not say what kind of 3800 he had! Is a 1986 V6 not 3800cc? The points I were trying to make were... to make sure hole for supplying oil pump intake is adequate.... hole can be under 1/2"... you wouldn't run a 7/16" dia. pick up tube in you big block Chevy ! All the other stuff is common sense ! V6 Buicks have a lot of internal oil leaks and by cutting down on cam bearing oil hole dia. helps! He is going to have to look and determine what he wants to do, also blueprinting timing cover passages and gear/rotor clearance is beneficial. we don't know what his lifter bore clearance is either! It doesn' t take much for Buick's to have so much leakage that they have very low oil pressure at idle . So if he wants to open up main and rod clearance he has to make sure he has good volume feed to pump ,Blue printed pump and good lifter to bore clearance !

[2seater]

I suggest asking/looking on the turbo Buick forums. Valve margins are also something to ask about.

Yea I'd listen to this guy after all there aren't many engine experts on this forum lol

An '86 GN 3.8 is not a 3800 as mentioned, but there are many similarities. Like anything on the internet, take the info or leave it. The Buick V6 likes tighter clearances if it sees time on the street. The oiling system is a less than stellar design, especially on the suction side. What clearances are in the engine now? I figured I would get dissed, but that's not a problem. Use SBC thinking if you will, I have no skin in the game.

[rewguy]

It is a 1999 model. ..out if a fwd car. I was told that it made 490 hp at the tires (15 lbs boost) with his last build. .... which was identical minus the now ported cylinder heads.

[The Radius Kid]

It is a 1999 model. ..out if a fwd car. I was told that it made 490 hp at the tires (15 lbs boost) with his last build. .... which was identical minus the now ported cylinder heads.

That would be a 3800 Series II.

[2seater]

That sounds pretty serious, so, how do the bearings look now? If they look good, why not stay with what has worked so far? It would be useful information to report, clearances, condition etc.. Good engine to work with in the V6 series, crossbolted mains, shorter deck height and just about as far as GM went with the development of a Wards Auto Ten Best Engines winner.