whyrun

Here's my Problem after getting my forged short block back from the builder. I remeasured my deck height and it appears my piston are .020 in the hole and I had planned for .010, My builder had told me that's what the block had been decked for but it looks like he didn't check it after final assembly. This was just a quick check I made at the shop on one of the cylinders I will go back and check all 8 more accurately to verify. But my question is this. I wanted to keep the quench at .037 with pistons
(-5cc flat tops) in the hole .010 and a .027 cometic gasket, so if I end up with the piston's .020 in the hole would it make sense to run a .017 cometic gasket to keep me desired quench or would that be cutting it to close for expansion between the alum heads and iron block..

I willbe running fully ported TFs heads and it will have some nitrous added.

mdacton

how did you check it?

rock the piston and check the top and bottom. add then divide by 2... that is the most accurate way I have found to get it. check each hole.

whyrun

I used a dial caliper with magnetic base and measured from the center of the piston.

I'm going to check it tonight with a depth micrometer, a friend borrowed it sometime back and forgot where it came from so I need to run by his place and pick it up.

using a dial indicator from the center of the piston I got like .019 to .022
and using a standard dial caliper at the edge of the piston from each side I was getting
.011 to .015

mdacton

you need this

whyrun

Thats what I have it just doesn't have the dial, it's the spin down type. I just talked to a friend of mine and he suggested that any quench in the range of .035 to .050 on a sbc with flat top piston's would be ok, that you really wouldn't see anymore gains by going closer.. so I'm kinda at a stand still.

whyrun

what is the general consenus here on Quench what are you guys running. I'm going to be around 11.8:1 very limited street car, solid roller etc etc..

marshall93z

Between .035 and .050 is fine, IMO. I was shooting for .036 when doing my build, but miscalculated the assembled length of rod/piston and ended up with ~.044.

I forgot that stock pistons compression height is 1.56 and what I bought was 1.55. No biggie, though.

sbs

If your measurements are accurate my main concern would be what else did the builder overlook/fail to measure.

rskrause

Don't worry about it. Won't make a difference.

Rich

Strictlyfishn

How do i replace my front passenger fog light? Can't find a opening to get to it.

Injuneer

Helpful hints:

1. Post in the correct forum. Replacing a fog light is not "Advanced Tech".

2. Post only on one forum. You have this on 3 different forums.

3. Do not "highjack" someone else's thread, by adding your problem to it. Posting something totally unrelated to the original post makes it even worse.

4. Include info about your car. The F-Body was made for 36 years, in two differnt car lines. Asking how to replace a part without telling us what specific year and model you have makes the task impossible.

String

You should always measure from the edge of the piston in the center of the bore. This will eliminate, or significantly reduce, the rocking of the piston in the bore and produce more accurate and repeatable results. Also, since you mentioned that your pistons are dished the center will be lower than the edge anyway. The -5cc would indicate a dish, not a flat top piston, unless you are measuring the valve reliefs.

whyrun

They are not dished the 5cc is in the valve relief, they are flatops