Is this the correct way?

 

.057 is a lot. The cheaper rebuild pistons many times have a shorter compression height. It will be fine for a cruiser. Measurement is the difference between the block deck and high point of the piston @ tdc measured at the axis of the pin. Yours looks like .0515"

 

that's a pretty fancy tool for you Fatcat, are you sure your qualified to use something like that!?

 

no.... use a flat bar across the top of the bore, and a feeler gauge. Then, use a stop and find absolute TDC .... then do math

 

Is the correct reading .0515 or .0485? I'm trying to learn. To me if the feeler gauge is "zeroed" on the cylinder then moved "up" to the block. You would use the red numbers which are negative. Just trying to learn, not saying I'm right and everyone else are wrong.

 

Good observation. If you look at the real small dial inside the large dial face you'll notice it is numbered from 0 to 9. In the first pic you see the dial is pointed directly at the 0. then in the next pic where he has it on the deck the small dial pointer has moved to a position between 0 and 1. This means that the large dial deflection is in the positive direction. Had that small dial indicator moved towards the 9 then it would have moved in the negative direction and you would then use the red numbers.

 

Looks like 64cc or 62cc and a thin head gasket will work for you. I never seen pistons so far down. Usually you will see .020 give or take .010
A thinner head gasket will make the chamber between the piston and the head small (higher compression). Thus cramming more Sh/t into a smaller box makes bigger boom!
Double check with the feeler gauge. Bring it to tdc and use a metal ruler standing on edge and slip the gauges under.

 

Makes sense, thank you

 

So after having to actually learn to use a precision tool I figured out I am actually .046 deck clearance with feeler guages and dial guage so it is what it is. I told Birdsmith last night I went back and read all the way back through this thread the other day and found it now all makes more sense and also found things I completely missed. I guess it's all just part of the learning curve though.
I am hoping to actually get my heads ordered this week, not a high-end head but after research, phone calls, text msgs and hours of trying to figure it all out, I decided to go with aluminum heads that are 64cc chambers. With that said, I should end up in the 9.31:1 ratio range depending on my head gasket thickness. I did speak with a machine shop and they told me the less expensive aluminum heads aren't great but of them they would recomend the Assault brand. I can get those heads, bolts and all delivered to my door for $685 not a bad price on a budget build. After talking to Birdsmith yesterday, I have also decided to upgrade the intake and possibly the carb. Today it is cold but I think I am going to do some cleaning and try to get the engine compartment ready to go, I may also go get the new tranny picked up...

 

FatCat reading your post has got me to thinking about the pistons I'm going to receive for my rebuild.
I was doing some reading over on this web site,http://www.hotrodders.com/forum/will...ld-217682.html
and apparently there are two different kind of compression heights for pistons. 1.56" and 1.54". It sounds like you got the 1.54" pistons. This would mean with stock pistons your pistons would be .025" below the deck but with these "rebuilder" pistons your are now .046 or thereabouts below the deck.
This is bad news for quench. Quench or squish distance is important for detonation prevention. In the Chevy 350 .040 to .035 is ideal for quench distance. Yours will be .061 even if you use the felpro .015 gasket. (.015 + .046 = .061). It would seem that your block has not been decked and still retains the 9.025" deck height.
If you want to achieve your HP goals quench is going to be important. That leaves you with some choices to make.
1) leave it alone and accept that this will be a cruiser lower HP build
2) Get new pistons with 1.56" Compression height to get .040 quench.
3) Get the block decked down to 9.00" to get .040 quench.
Options 2 and 3 will allow you to get more compression and better detonation prevention to meet your HP goals.
If I had to WAG it I would say 250-300 HP max at the crank if left as is.
With better compression and quench 350-370 HP depending on RPM, heads and intake. Just a guess. Someone like Mako63 could probably give you a better idea.
Aluminum heads do allow higher CR than iron, about one point. Good quench can also add 1 point of CR. Given that It may be logical that bad quench can take away one point. When I worked on racing bikes (my own) quench was critical to getting away from detonation.

I have no personal experience on these engines (other than the rebuild I'm doing now) but I have done some extensive reading on the subject. so factor my lack of experience into what I am saying. Perhaps someone with real world experience on these engines can confirm or debunk what I am saying. So far your progress is looking good. Like the color of the block.

 

Hey brother thanks for the information. The pistons I put in are 1.56 Comp Distance. I am not sure on the detonation issue but I sure had a lot of problems with that prior to the rebuild. Maybe someone will address that issue as well and confirm. I guess I would have to tear it back down to have the block decked but If I needed to do that I guess it wouldn't be the end of the world and the original idea was to just rebuild a cruiser.
I actually read your post on detonation las night.

The block was painted with Duplicolor Metalcast paint and clear coated with Duplicolor engine block ceramic enamel.

Anyone?

 

So you got the correct pistons at least as far as pin height goes and still they're are .020 farther down the hole. How is a guy supposed to plan out quench and CR when the aftermarket keeps throwing you curve *****. I mean seriously you think you got this all planned out and then get pistons that add .020 to your quench and compressed volume.
I'm having the same kind of issues. Nothing is as advertised. 15.6cc pistons are 17ccs, 76cc heads are 80ccs, the "64cc" heads I purchased turned out to be 67cc's. Now the piston's I'm getting are probably going to be just like yours and I'm going to have to figure a way to get my quench back.
When I asked at the machine shop about taking off some of the deck I was told that they can only square up the deck and what they take off is what ever is necessary to square the deck. Could be .020 could be .035. So that is a big unknown until it's all done.
So I can't even plan on which head gasket I'm actually going to use until I figure out what I need to take off to accommodate the pistons to get the .040 to .035 quench desired and I haven't even factored in piston to valve clearance issues yet. Sheesh!
Ok enough of that. You'll be dealing with the same thing if you want to get your quench and CR where you want it. I figure this is why engine builders get paid for their services. They've done this enough times to have this all planned out in advance. Experience, you can't replace it with book reading.

 

I am telling you, I am thankful Scottp caught my mistake when I ordered my first set of piston's or I would have really been messed up!! It will give you the valve relief when you look them up, mine are +.005 and yours will probably be the same.
I would have never made it this far without this thread...

 

so what are you gonna do?

 

I am first hoping someone will wheigh in on the possible problem with quench and detonation. If I get word that I will be ok, I will probably try to find a .025 head gasket and with 64cc head, .005 effective dome, 4.030 bore and .046 deck clearance that should get me 9.66:1 CR and I will move forward. Just not sure if I may need to go with a .015 head gasket for quench. If they are open, I am going to order the heads tomorrow. A .015 head gasket would put me at 9.89:1 CR.

 

wow, when did you start learning all this fancy math and engine stuff? I'm impressed, ok, keep us posted.

 

It made me sound all official huh!?!?!
You guys have taught me a few things..

 

haha, yep! what are you gonna do for exhaust? if you said, I forget

 

You need to measure all 4 corner cylinders. Many factory blocks are out of square. Correct way to measure is to put a straight edge across the cylinder and measure the gap to the piston with a feeler gauge.

I would really think hard about having the block decked if it's really off as much as almost 050.

 

I am planning to go with headers. Superbuickguy had a set he said he would sell me. I just have to figure out if by the time I was to pay shipping if it is feasible to do that or buy new. My exhaust is Y pipe from the motor to a single 2.5" pipe to the muffler and out to the duals.
It appears to be fairly new so not sure if I can incorporate the headers into that system or if I need to run true duals. What say you?