Inliners International Forums General Discussion Blown and Injected Stock cast pistons in a 292 turbo engine

Guy's,
Beater had asked in another post about using stock cast pistons ina turbo 292 application.

I say yes.

The stock 292 piston was designed for heavy duty use. Normal applications would put them in detonation and heavy lugging sittuations daily.
The top ring land is a full 3/8" thick (turbo size) and is supported with a steel plate that goes under the ring across the entire piston! That makes them heavy.
The compression ratio with the stock piston is also good for turbo use.
I would suggest limiting boost to 6-8 PSI and appr 30-32 degrees timing while under boost. If boosting higher than you need to be able to pull more timing.

Of course the correct A/F ratio must be maintained under boost. It is alarming how much the fuel demand goes up with boost.

The stock piston is much tougher than any other stock chevy inline piston and also the V8 pistons until you get to the Industrial hauling gas burner 366 and 427. Tom

I've got a set of new .040 over Silv-o-lites. I don't think they have a steel plate but I didn't know the stock ones dod either. Do all stock replacements have a plate? Would the silv-o-lites work? Beater

I'm kinda new to the inline 6, well the performance side, ive had multiple novas with this engine. I'm only 25, so i missed their glory days, but i am still a firm believer in them. I have a turbo i was given for free (I'm a heavy diesel mechanic) but it is extermely large and I don't think the lil 250 would be able to spin it very well. Its A/R is only 60 or 70 (I cant remember exactly) but its from a Freightliner Century Day Cab with a Detroit 60 Series. I was thinking of trying a Garrett T25 or similar sized Holest. I was wondering if anyone had any suggestions on what to run? I know I had an article from an long past issue of Chevy High performance where GM actually toyed with a turbo camaro/nova i6 in the late 60s/early 70s. Its highway passing speed *50-70* was cut in half from 12.5 seconds (with the stock 1bbl and 2.73 rear/2spd pwrglide) to 5.7 seconds! Thats a big change, and on low boost, but I also know they were using export pickup 7.5:1 pistons. I was wondering, since the 292 has such HD pistons, how the stock 250/230 pistons were? I'd like to run about 8-10 lbs of boost. To begin I'll be running a stock 1bbl carb, then eventually moving up to a 2bbl tbi or 4bbl mpfi injection system with a custom intake manifold, full standalone engine management etc. I'd love to turbo the 4200 and slap it in, but for now, a stock setup with a mild turbo/boost setup will work with increasing fuel mileage and a little boost of power, I mean, the mid 80s 305 was almost identical HP/TQ numbers as the 250i6 in 1970 with a 1bbl! So some mild boost should get me 45-50hp and the i6s are torque monsters, so im sure itll help there too.

Any suggestions?

*Sorry,kinda long for a first post!*

Dallas

The KEY to making the stock parts live under say 8-10# boost is engine management. Make sure the AFR is no leaner than say 12.8:1 under boost and be gentle with the timing. If you stay away from pre-ignition and detonation it be fine otherwise you will have an oil pan full of metal in a hurry.

Make sure your fuel delivery system is up to the job - its amazing how much fuel you will need, boost reference the fuel pressure reg.

I plan on eventually going to a tbi or mpfi setup, but for now think i can find a good 1bbl carb? Or should the stock one be ok on 8lbs? i also plan on doing a points elimiator kit as well as an MSD setup (I have a 6A box and blaster 2 coil sitting around) I was thinking the holley tbi setup, but I will have to find a manifold built for it which i know I can. But how will the factory *3 barrels to small* carb work? lol. Also, your saying be gentle with the timing, should I keep it close to stock timing or say 12degrees btdc? Ill have the advance hooked up so itll advance under boost, but what would a good base timing be? or at least a good starting point. And should I run colder plugs to be safe with say .040 gap?

For the price of a MSD 6BTM you can by a megasquirt that will do timing control with only a few wire and 1 hose to hook up.

While others on here tend to stay with mechanical solutions I think they are leaving a lot of performance on the table. tlowe runs a 292 under boost so maybe he could provide his timing table.

New boy on the block. Gary Lund .
I am interested in putting my 292 in my 53 BelAir and yanking the 350. I got a free set of .060 flat top pistons.I want to run a turbo as I haven't done one yet. I also have found a older Offenhauser 4 barrel manifold that will bolt up to stock exhaust manifold.Interested in know how much the lump ports would help with a turbo.Some of these replys are really old , do you think we could start a fresh one?? Thanks 1Studedude

Rickyboy,
Glad to see you here on the Inliners site!

The lumps will help some with the turbo motor. But the turbo motor will do very well without them.

I have them in my motor now and am going to pull them out and see if it runs better. It pulls very hard as is.

You are welcome to start new posts as you need. There is alot of info in the old posts. The old info is still good. Tom

Tom , thanks for the info. I want to build my 292 something like this; 4 angle valve grind,an old offy manifold with a adptor for to make this holly throttle body work on it ,use the FREE set of .060 over flat top pistons,and I would like to use a roller cam and rockers.I think the 3" stock exhaust manifold will be ok to use as the intake will bolt right to it. Then run it through my $50 200r4 trans. Allmost forgot about the new lump ports also.
Does this sound like a solid plan??? I can use all the info I can get.Thanks again PS think the turbo is out of my budget

Ricky,
Sounds like you are on the start of a fun project. Don't think about a roller cam, that will end up costing you over a 1000 with lifters.
Also a solid running 292 will tear up a stock 200r4. But it will be fun! I tore up a 700r4 with mine in N/A form. Tom

Roller cam not necessary,unless you just got some $$$ burning in your pocket.
CNC dude can get the billet cams for a good price if your interested,,maybe run a hydraulic roller?

It seems guys w/there Biuck GN & Turbo T-Type Regals use the stock 200R4 trans into the 12's (1/4 mile) w/not much problems.

Those cars weigh approx 3600 lbs.

The Buick GN trans are better than a standard 200R4. But they can be built correctly to handle a desent amount of HP & torque.

I am still running a completely 100% stock 700R4 trans in my Syclone, dynoed it 386 HP & 550 ft lbs of torque @ 21 psi.

I am just on the verge of running 11's,can't wait!

MBHD