shee4speed Posted September 24, 2007 Report Posted September 24, 2007 Well I just installed the head with 21cc domes and am getting 130 psi. I thought it would be around 140psi. I'm at 1800 ft above sea level. Will the compression go up after I run her? Maybe thats all it will have. Quote
shee4speed Posted September 24, 2007 Author Report Posted September 24, 2007 Thats a good question. What would make that vary from stock? And what is the stock squish? Quote
chevrolet banshee Posted September 24, 2007 Report Posted September 24, 2007 probity a stupid question but what is a squish??? Quote
shee4speed Posted September 24, 2007 Author Report Posted September 24, 2007 I think its the amount of space between the head and the piston when the piston is all the way up. Quote
chevrolet banshee Posted September 24, 2007 Report Posted September 24, 2007 ok that makes sense Quote
BellicoseBanshee Posted September 24, 2007 Report Posted September 24, 2007 probably a stupid question but what is a squish? A picture is worth a thousand words.....and it is better than my late-night explanation would be! Quote
dajogejr Posted September 24, 2007 Report Posted September 24, 2007 Nice post, Bellicose... To add, you should use solder (I use .092 or .093 diameter WITH flux core, makes it easier to smash and check) and you HAVE to check it parrallel to the wrist pin. If you check the front or back of the piston, it will rock in the bore and you will not get a true measurement. Get digital dial calipers from the tool store ( I paid 30 bucks...@ Harbor Freight) to check the thickness. IMO... .040 to .050 is where you want to be. Quote
BellicoseBanshee Posted September 24, 2007 Report Posted September 24, 2007 Nice post, Bellicose... To add, you should use solder (I use .092 or .093 diameter WITH flux core, makes it easier to smash and check) and you HAVE to check it parrallel to the wrist pin. If you check the front or back of the piston, it will rock in the bore and you will not get a true measurement. Get digital dial calipers from the tool store ( I paid 30 bucks...@ Harbor Freight) to check the thickness. IMO... .040 to .050 is where you want to be. That is why I threw up a picture (gotta love CAD). At O'dark-thirty, I was not thinking clearly even though I could not sleep, so I am glad you added the technical stuff. For the record: I found that on this website. Quote
shee4speed Posted September 24, 2007 Author Report Posted September 24, 2007 Nice post, Bellicose... To add, you should use solder (I use .092 or .093 diameter WITH flux core, makes it easier to smash and check) and you HAVE to check it parrallel to the wrist pin. If you check the front or back of the piston, it will rock in the bore and you will not get a true measurement. Get digital dial calipers from the tool store ( I paid 30 bucks...@ Harbor Freight) to check the thickness. IMO... .040 to .050 is where you want to be. So you take a piece of solder and stick it in the plug hole and turn the motor over?Then measure the thickness of the crushed solder? Also will my compression go up after heat cycled? Quote
dajogejr Posted September 24, 2007 Report Posted September 24, 2007 So you take a piece of solder and stick it in the plug hole and turn the motor over?Then measure the thickness of the crushed solder? Also will my compression go up after heat cycled? It might go up a hair once the rings seat, but probably not very drastically... Quote
sredish Posted September 24, 2007 Report Posted September 24, 2007 (edited) Your fine. It might settle in at 135, maybe but if you'd have asked, I'd have told you to expect 130 to 135. IMO, 21cc domes are a waste at anything over 500'. You can push it up to 150 to 155 with pump gas so there's free power, maybe not loads but free power when your choosing dome size. You should be able to get away with 19cc domes at 1800' on pump gas, be hitting 155 and you'd notice it. Edited September 24, 2007 by sredish Quote
shee4speed Posted September 24, 2007 Author Report Posted September 24, 2007 I should have checked closer,I'm at 1290 ft. Will be going to glamis. I guess I can switch out those domes. Quote
Snopczynski Posted September 24, 2007 Report Posted September 24, 2007 you have to check it at the side also, not the front or the rear of the cylinder. Quote
shee4speed Posted September 25, 2007 Author Report Posted September 25, 2007 When I decide to replace my domes, do I need new o-rings? Quote
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