block and head machining questions

bmxmon · 09-21-2004, 07:35 PM

I am going to be getting my block bored and honed, after talking to a machine shop, i figured it was a good deal at $125. I want to build compression, since the engine is out of a 79, i figured it has some room for improvement. I was thinking about getting my heads plained to help build compression and level things out, but the machine shop guy said it would be easier to build compression by using domed or some other type of pistons. (he did say its a good idea to get the heads plained anywho) The thing is, I was planning on getting a kit from PAW, the rebuild kit for $300. Which comes with pistons. Its only like $30 for each head, going up the more they plain. Any thoughts/other ideas?? I am planning on getting the performance cam from them, and already have an edelbrock performer 289 intake and headman headers for it. Its pretty much a budget build, and a learning experience. (I am the one rebuilding my 302 in school, if anybody remembers) Thanks for looking and any and all info.

Ieatcamaros · 09-21-2004, 09:46 PM

Well, if you get into dome pistons that shoots the budget build out the window. I remember your other thread. If my memory serves correctly, you can take up to .050" off the heads. The thing is, you will have to plane the intake if you go that far. About .015-.020 is the most you can take without having to plane the intake. If this is wrong, please correct me.

Rev · 09-22-2004, 09:18 PM

I would get the shop to deck the block as well to make sure everything is square. I think you can angle mill the heads up to .050" without doing anythig to the intake. At least that's what my machine shop guru says. Get an opinion from your shop guy about decking the block and also how much you can mill the heads without intake machineing.

Rev

DblAdigger · 09-25-2004, 06:14 PM

Get the kit with flat top pistons. After the block is bored, mock it up to see how far down the pistons are. If .010/.015, have the block decked to bring to .000. Decking the block is a much better way to raise compression, compared to domes or head milling.

Rev · 09-25-2004, 07:08 PM

That;s what I did. Flat top forged or hypereutectic pistons with 0 deck height and 60cc or so combustion chamber volume . You want .040" head gasket to get 9.5/1 compression. You'll get good street performance from that combo. Just ask your auto shop teacher.

Rev

bmxmon · 09-26-2004, 01:39 AM

awesome, sounds like a good idea. So get it decked to .00, and run a .04 gasket. Can they deck it with the pistons and crank in, or is it best to take it out after test fitting it?? I would think it would be better for me just to have them measure it, so its 100% accurate. Also, how do i measure what size combustion chambers i have, since i will get the heads plained i would guess that would change the size. thanks, i didnt even think about decking the block. My brother in law did that to his race car, and he whopped ass, lol. He did alot of stuff thats kinda funny though, things in the gray of the rule book. Like his compression was really high, so he had to run race gas,(or airplace or something) but the rule book said that he had to run regular or something, so he just mixed it, since it didnt say how much regular they had to run,lol.

Rev · 09-26-2004, 02:21 PM

You can get a kit from Summit or Jegs to cc your chambers. it's not very difficult I think. What you do is lay a flat plexiglass plate over the deck of the head with valves and a sprk plug installed. The plate is sealed to the deck with a small amount of vaseline so it won't leak. There is a small hole in the plate or maybe two holes so air can escape from one while being filled from the other. You drip a liquid (colored aocohol I think) into the hole from a pipette (a tube calibrated in cc's that holds the liquid). The amount of liquid needed from the pipette to fill the chamber tells you the volumn of that combustion chamber. It's what they call "cc'ing the heads".

If you don't want to buy the kit, most shops that port heads would probably do it for you for a small fee. Your school shop might actually have that kit and it could be a learning experience for the whole class. Just a thought

Rev

09-21-2004, 07:35 PM	#1
bmxmon Registered Member Join Date: Mar 2004 Location: Minnesota Posts: 950	block and head machining questions I am going to be getting my block bored and honed, after talking to a machine shop, i figured it was a good deal at $125. I want to build compression, since the engine is out of a 79, i figured it has some room for improvement. I was thinking about getting my heads plained to help build compression and level things out, but the machine shop guy said it would be easier to build compression by using domed or some other type of pistons. (he did say its a good idea to get the heads plained anywho) The thing is, I was planning on getting a kit from PAW, the rebuild kit for $300. Which comes with pistons. Its only like $30 for each head, going up the more they plain. Any thoughts/other ideas?? I am planning on getting the performance cam from them, and already have an edelbrock performer 289 intake and headman headers for it. Its pretty much a budget build, and a learning experience. (I am the one rebuilding my 302 in school, if anybody remembers) Thanks for looking and any and all info.

09-21-2004, 09:46 PM	#2
Ieatcamaros Domestic Rice really sucks! Join Date: Apr 2002 Location: KY Posts: 973	Well, if you get into dome pistons that shoots the budget build out the window. I remember your other thread. If my memory serves correctly, you can take up to .050" off the heads. The thing is, you will have to plane the intake if you go that far. About .015-.020 is the most you can take without having to plane the intake. If this is wrong, please correct me. __________________ The sig says it all.

09-22-2004, 09:18 PM	#3
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	block decked? I would get the shop to deck the block as well to make sure everything is square. I think you can angle mill the heads up to .050" without doing anythig to the intake. At least that's what my machine shop guru says. Get an opinion from your shop guy about decking the block and also how much you can mill the heads without intake machineing. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

09-25-2004, 06:14 PM	#4
DblAdigger Registered Member Join Date: May 2003 Location: So Cal. Posts: 14	Suggestion. Get the kit with flat top pistons. After the block is bored, mock it up to see how far down the pistons are. If .010/.015, have the block decked to bring to .000. Decking the block is a much better way to raise compression, compared to domes or head milling. __________________ Some people can break a cannon ball, in a sandbox, with their bare hands.

09-25-2004, 07:08 PM	#5
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	That's what I did That;s what I did. Flat top forged or hypereutectic pistons with 0 deck height and 60cc or so combustion chamber volume . You want .040" head gasket to get 9.5/1 compression. You'll get good street performance from that combo. Just ask your auto shop teacher. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

09-26-2004, 01:39 AM	#6
bmxmon Registered Member Join Date: Mar 2004 Location: Minnesota Posts: 950	awesome, sounds like a good idea. So get it decked to .00, and run a .04 gasket. Can they deck it with the pistons and crank in, or is it best to take it out after test fitting it?? I would think it would be better for me just to have them measure it, so its 100% accurate. Also, how do i measure what size combustion chambers i have, since i will get the heads plained i would guess that would change the size. thanks, i didnt even think about decking the block. My brother in law did that to his race car, and he whopped ass, lol. He did alot of stuff thats kinda funny though, things in the gray of the rule book. Like his compression was really high, so he had to run race gas,(or airplace or something) but the rule book said that he had to run regular or something, so he just mixed it, since it didnt say how much regular they had to run,lol.

09-26-2004, 02:21 PM	#7
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	cc'ing chambers You can get a kit from Summit or Jegs to cc your chambers. it's not very difficult I think. What you do is lay a flat plexiglass plate over the deck of the head with valves and a sprk plug installed. The plate is sealed to the deck with a small amount of vaseline so it won't leak. There is a small hole in the plate or maybe two holes so air can escape from one while being filled from the other. You drip a liquid (colored aocohol I think) into the hole from a pipette (a tube calibrated in cc's that holds the liquid). The amount of liquid needed from the pipette to fill the chamber tells you the volumn of that combustion chamber. It's what they call "cc'ing the heads". If you don't want to buy the kit, most shops that port heads would probably do it for you for a small fee. Your school shop might actually have that kit and it could be a learning experience for the whole class. Just a thought Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

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