Inliners International Forums General Discussion Engines 292 engine build advice needed

I have a 1953 Chevy Club Coupe and I am going to be installing a 292 Engine and a 700r4 and the rear axle will be swapped out to open driveline. I am a member on another forum where I have my car's build thread going.

I have been trying to figure out if I will be running a turbocharger or not on my engine for several reasons.
I have already had my engine block machined and short block assembled and I am currently working on installing lumps in the cylinder head myself. I know the machine shop I took my engine to does good work and is a well known race engine shop but in retrospect, I wish I had gone somewhere else where the machinist would have been more involved and interested to make sure I got what I wanted and made suggestions to get there. Halfway through the process I felt like they just wanted to get me in and out and make some money and get back to their big blocks with super chargers for their cigar boat customers.....I know for a fact that one of the guys was very annoyed to have to work on my engine.

At this point my engine is bored .020 over, all new clevite bearings, melling brass freeze plugs, mellings oil pump, standard hydraulic flat lifters, sealed power brand cast pistons, hastings rings, crank ground and balanced, .005 shaved off deck, .050 shaved off cylinder head (67cc chambers now), new SBI brand valves (stock sizes), new exhaust seats, new timing gear set, comp camshaft, all the rod and main bolts were re-used in assembly, and they did my bearing clearance checks for me. There is .050 deck clearance and the pistons have a full dish instead of the D shape the stock pistons had. I have been told that is a bad deck clearance and I will have a lousy quench. The machinist told me that I have about an 8:1 comp ratio.

As of right now I am thinking of two build plans.

First plan- Naturally aspirated, swap pistons for LPG style pistons and bring the comp ratio up to 9:1 and use a MLS gasket to get the quench gap as low as possible which would be around .080 once assembled.

Second plan- Turbocharger, intercooler, swap cast pistons for forged pistons and keep the lower comp ratio. Do I need a good quench for a turbo engine?

Either plan will be using a megasquirt 3 efi computer to control fuel and spark, and a GM TBI, and a wideband 02 for tuning purposes.

I don't know anything really about what turbos would be good and what to expect to pay for them, and my HP goal has always been around 200-250 or maybe a little more.

It is a tough call to make for sure. But at the minimum, you should be at the 200 HP goal without a turbo. Also, EFI is cool, but not that friendly with the siamese head design that these engines use, so that may be more of an issue than your quench quandry.

Ok a few comments:

1) unless you plan on running sequential fuel injection later MS3 is overkill. MS2 with extra code will do fine for what you want to do. If you decide to run sequential now check Tom Lowe's thread on his turbo 292 - the 292 intake ports need to have dividers installed to do sequential. The TBI could be used as a throttle body for seq. injection if you remove and block the resulting hole where the fuel comes in. This would give you the needed TPS signal. You will need to run a BBC TBI to get enough fuel and boost reference the regulator if you run boost. Use a TPI type pump.

2) if you keep the boost low (8 psi or so) AND tune carefully then you can run the cast pistons BUT you must keep the engine out of detonation. 9:1 is fine even with boost.

3) which ever way you go do make the change to fix the quench problem - 0 deck the block and run the mls gasket(check piston to valve clearance first..).

4)MS can do boost retard - and activate a water/methanol injection kit under boost.

Too bad you didn't stop here earlier. There are other options that are less costly than rebuilding 60's vintage engines, that make 275/290 HP in stock form for $2000 to $2300 complete with 4sp OD transmission. But you have already spent your money.

I have the comp cam card specs but I don't know how to post an image on here. It's not like the other forum i use?
I did start with the intention of sequential fuel injection but as I learned about the siamese ports and other issues, I chose to go with the gm tbi throttle body instead since it has the two injectors on top and therefore it will give the homogenous a/f mixture to the intake like a carb would.

1) I chose the MS3 for the possiblity of sequential injection in the future. Not on the 292 but potentially for another project someday where i would swap the system over. Or in case I get a 12 port head I also just wanted the latest version and it's not much more money than MS2.
2) I was actually thinking of swapping out the pistons for forged no matter which build up I do.
3) Would it be acceptable if I just have the forged piston manufacturer build them with a higher compression height to bring the quench to .050 or so? I really do not want to disassemble the engine again and do more machine work. Plus I read somewhere that you should NOT machine anymore off the deck of these blocks. I think it was the leo santucci book. I need to read up on checking the piston to valve clearance. I don't know how to do that yet. This is my first engine build so I don't have all the tools and experience.
4) I wasn't sure if MS did that yet. That's really good though! I haven't given any thought to an injection kit yet.

Are you talking about the v6's?

He's talking about the Atlas Vortech inline 6 engine.

Oh....Well I wouldn't want to put something that new in this car right now. Maybe if the 292 were to ever blow up on me then I would go a different route.

After talking to twisted6 last night, I believe I am leaning toward keeping the engine naturally aspirated. There are too many things to change and a lot more money involved with the turbo plus I don't think I want to run an intercooler and all the additional piping and I pretty much have to in order to drive it here in Texas because of the heat. Also, my engine was not bored with a torque plate and that seems pretty important for a turbo application.

With custom forged pistons with a higher compression height, that should give me around 9:1 ratio or higher and the pistons have a small dish that will clear the valves I believe but I'll talk to the manufacturer to figure that out.

I'm going to send my damper to damper dudes and have them rebuild it. Very professional service over the phone and he said he would do an additional service in order to make sure I don't have any problems in the future since I am bumping up the power from stock.

You will need to have your machinist measure your new forged pistons compared to your cast pistons and make sure your cylinders have enough clearance before they are installed in the block. Also, a torque plate is important whether your building a blown engine or not.

I called the machine shop last night and I didn't get the owner but I did talk to one of the guys that was there after hours. He suggested that I try to find an off the shelf cast piston in order to save a lot of money vs. a custom set. I don't think I should bother with that since it seems like more of a PITA than I want to deal with at this point and most likely there would still be additional machining required to make anything work and so the custom pistons would be more money up front but the least headache to install.

My bore is 3.8955 with a compression height of 2.010 and pin diameter of .928

All I have to do is get a piston set with the same specs EXCEPT for a 2.050 (10 in the hole) or 2.060 (0 deck) compression height. 10 in the hole would be for the MLS gasket I have and 0 deck would be for the stock fel pro gasket. That would make my quench much more acceptable, about .040, and raise the compression and I can put the engine together.

He also talked about changing out connecting rods and all this other stuff and I don't need to do that. This engine is not going to make that much horsepower or be under enough stress to require I-beam or H-beam rods.

Clearance to the bore? What is acceptable? My current set has .0015 according to the build sheet.

As far as the torqueplate though, I just want someone to confirm that it is OK that it wasn't used for my particular street engine purposes. If I was building a racing engine then I would definitley have it done now that I know about it. They didn't do that from the factory did they?