MikeGyver

I'm building a 383 turbo'd stroker. Is it a bad idea to Zero deck the block to compensate for the slightly larger piston dish that I would like (-31cc dish)?
What are the pros and cons of different deck heights?

STRYKER

I can't say that I have ever worked on a turbo engine but I do know that in the Advanced Tech section, quench height has been discussed pretty thorough and has some really good posts by people that really know their stuff.

Check this one out for starters ---> https://www.camaroz28.com/forums/sho...ghlight=quench

cusz28

what is your compression ration with your piston where it is? one reason for zero to negitive deck height is to keep as much of the combustion in the head as possible and to help evacuate as much of the spent gasses as possible vs having it trapped in the cylinder.

MikeGyver

I'm building 383, I have no parts yet, which is why I'm asking now.

I'm thinking zero deck the block, set my quench with a .039" head gasket, and size my piston dish accordingly to give my desired compression ratio of about 9.2:1... as opposed to setting my comp. ratio with the gasket thickness and ending up with a larger quench.
Does this sound like a good plan?

MikeGyver

Here's another issue. How do you know if your valves are going to clear your pistons?
I guess with a larger than 20cc dish it's probably not an issue though, right?

jakesz28

I think with power adders the motors may benifit from a larger quench height. That being said I have a .40 quench with 350hp of nitrous. But the next build will have a quench height of .050-.060.

cusz28

your right on track with building your engine. build it with a quench of around .035-.040. you can use a good gasket at .035, and you can run the zero deck you wanted. your also right on with using dished pistons to lower your c/r, but make sure your quench doesn't dip much higher than .050. as far as your valve clearance, put your piston at tdc with some clay on top about .1 thick, then take bare head and put your valves in it and put it on the motor without rockers or springs. push the valve in the cyl until it just hits, mark the valve stem on the seal, then pull it back, and mark it again. this is the max lift with your safety margin. good luck on the motor, sounds like you have everything down pretty good.

rskrause

You can pretty much ignore quench on a blower car. The high induction pressure and flow generate plenty of turbulence in the chamber.

Rich

MikeGyver

It's my daily driver so it'll rarely be under boost percentagewise (turbo).
Just ignore it all together because I may do a few boosted pulls throughout the day?

cusz28

every little bit helps when building a motor from ground up. it may not add much, but it will help control detonation vs a non quench. boost + detonation = many broken parts.

rskrause

There will be no tendency to detonate when it's not under boost. Don't give it a thought. What ever is the easiest way to get the desired CR. Pistons like this work great for a boosted motor. Notice the complete lack of a squish pad.



Rich

cusz28

every piston has quench, no matter what shape. the main point is, better safe than sorry, and every little bit helps. Plus, if he's not under boost at all times, quench may help more than you may think. in some cases, an engine may even have a tendency to detonate at a lower compression ratio if it doesn't have proper quench vs proper quench at a higher c/r. whether deemed necessary or not, quench is worth building into every engine.

cusz28

oh, and looking closer at those pistons, they do have a "squish pad", it's the little flat ring around the top of the piston. it "squishes" the mixture closer into the center. Feel free to scrutinize, but don't disprove facts.

96capricemgr

The most impressive Impala I know the 434ci Donovan block car boost and a little shot of nitrous to cool it, says his is .080 quench, like Rich said, don't worry about it with boost. That motor propels over 4200lbs to over 145mph in the quarter.

STRYKER

Lol, you call what Mr. Green has a "little" shot of n2o ? Ok, well maybe compared to the total package of what he is running...............maybe.