Does anyone know how far in the hole these sit and or to get 10.3:1 how much you need to take off the deck. The info is rather sparse and I dont have the calculations nor am I probably capable of calculating it. Id like to find a piston that will give me a true 10:1 10.5:1 while giving it a safe shot of 100hp of laugh. Thanks.
More helpful to the forum to start with a build plan including what you have, the intended goals, and the proposed parts. It seems presumptuous to start off specifying an exact compression ratio and state that you don't have a way to calculate, measure or possibly plan this.
I would start by measuring the deck height and also checking the CC vloume of the heads you are using. From there you can sort out the details like head gasket thickness and milling options to get the compression where you want it. Many of us prefer to use custom pistons to get exatly the compression ratio we want without needing to mill the heads and or block excessively.
ok its 73 455 and wanting more compression is all yet run on pump gas. I dont know, isnt factory heads 71 or close in CCs.. I dont need exactly 10:3.1 its just thats what its advertised with the wiseco piston. Anything around that 10:1 would be good but Im looking to do so without the milling/decking thats needed for some of the pistons I have seen. Surprised someone hasnt moved a pin down a little bit to raise the height a little to get closer to 0 deck instead of .050 in the hole or whatever. With a 40 gasket the quench starts to get ridiculous or does it matter with open chamber heads.
The Wiseco pistons are probably just like most 455 pistons on the market today. Read this, http://trishieldperformance.com/470--what-and-why-.html
Larry Thank you! An answer!! not a question to a question. This article is exactly what I was looking for and answered the question perfectly. Jees, some people... What cam I run, what Im doing with it, what gear, what car, what color, and who the hell I voted for is my business or I would ask for cam help etc ifthats the area I needed it in..Thanks again for the answer and helping. Happy motoring.
Apologies for the questioning of your questions. There is a huge majority of threads that start off with great misinformation or less than adequate understanding. It's just as frustrating for contributors to see twenty pages of someone struggling with a less than ideal build that was all completely avoidable from the onset. The compression height will be exactly as you need it to be when you order your custom pistons. I strongly recommend the use of custom parts as they often justify their cost saved elsewhere.
You're welcome, glad I could help. In our world of "alternative facts", sometimes, it's difficult to get a simple answer to a question. Have a look at this article, http://www.empirenet.com/pkelley2/DynamicCR.html At the end is a downloadable calculator. I keep it on my computer desktop. Very handy to have. Part of it is a static compression calculator. You can play with different factors and see how each affects the static compression. Then when you want to choose a cam, you can input several and see how they affect the dynamic compression, pretty neat.
To be fair...I wouldn't have questioned a thing if the OP hadn't specified raising his compression to an unlikely to survive pump gas static compression number without a very well thought out plan (let alone the nitrous use) and at the same time stating that he doesn't have the capability to measure or calculate things, AND an uncertainty of what to do with machining and how it affects quench because he isn't certain IF that will affect his project. The only reason I backed down from that is the assumption that his user name puts the vehicle at an altitude that makes sense for the compression ratio. Talk about a 'paradigm shift'. I would say it was completely justified, given the uncertainties the OP interjected to the thread. If that makes me out of line, then in your best Steve Martin voice "Well excuuuuuuuse me!" Happy Motoring
No no, not you.. not anyone. Im a happy go lucky, just wondered about pistons. Kinda the same as what Olds did is what I came to conclusion. I dont know who the other guy is and dont care, hes a good guy too, just didnt feel the need nor the reason to spell out my entire build and or what I was doing. Who cares, just want 10:1 Id like to stay in good standing with the board, a lot of good info, will just stop short of giving up first born. Yep, I had no clue about how to get there with the 455 Buick without decking blah blah ...but know how to on most all other engines.. well not a Chalmers. If I sound harsh, apologies, its not who I am, Im just not Jim Comey. F85? Blasphemy! lol
Great stuff and good to brush up on static, dynamic, bleed off, cylinder pressure, etc... Ok from now on, Ill just ask you. lol. I know this stuff isnt engine building 101. All in conjunction. I do Olds motors, had a guy I met spend big bucks on a rebuild at a shop on a 400. He was all happy until he stepped on it and.... should have stuck with a 4 cylinder single carb. A lot more goes into it than swapping out parts. Thanks again.
