Forums
New posts
Search forums
What's new
New posts
Latest activity
Members
Current visitors
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
EarlyBay Forums
Technical
Deck Height - One Cylinder is different, is this okay? Plus 7.3 compression ratio?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Help Support Early Bay Forum:
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Message
<blockquote data-quote="atafonso" data-source="post: 603427" data-attributes="member: 23592"><p>1- It is not going to be lazy if you run 7,3:1. In fact, using a lower compression allows you to run more timing, which makes up or more of the power lost by the slightly lower compression. Read on Gene Berg articles, he used lower compression and had great results. I use it on my 1776's with stock cam and they always make more than 70bhp(corrected crank) on the rolling road. Runs very cool and no detonation at all.</p><p></p><p>2- The difference can be a problem on the sealing surface between the barrel and head. The head will have to be slightly "twisted" to seat properly on the lower cylinder.</p><p>Try measuring all four barrels on cylinder 4 and see if it is actually the barrel. If it stays the same, take one barrel, try all four pistons and check. If still the same, you can be sure the barrels and pistons are fine, problem will be the rods wrongly resized(if they have been reconditioned before), crank ground slightly offset or the case surface has been machined incorrectly/worn due to loose heads.</p><p>You can check the case and if you don't see any barrel marks, chances are it has never been machined, so my bet would be the rods all else being ok. </p><p>On the AA pistons and barrels i found to have differences never more than 0.05mm, but you never know.</p><p></p><p>4- More than 7.5:1 will contribute for a slightly hotter running engine; you will already produce more heat with the 1641 pistons; 7.7 should be fine but if you preffer more reliability than to extract every single bhp you can from the engine, 7.3 would be your best bet IMHO.</p><p></p><p>Abel</p></blockquote><p></p>
[QUOTE="atafonso, post: 603427, member: 23592"] 1- It is not going to be lazy if you run 7,3:1. In fact, using a lower compression allows you to run more timing, which makes up or more of the power lost by the slightly lower compression. Read on Gene Berg articles, he used lower compression and had great results. I use it on my 1776's with stock cam and they always make more than 70bhp(corrected crank) on the rolling road. Runs very cool and no detonation at all. 2- The difference can be a problem on the sealing surface between the barrel and head. The head will have to be slightly "twisted" to seat properly on the lower cylinder. Try measuring all four barrels on cylinder 4 and see if it is actually the barrel. If it stays the same, take one barrel, try all four pistons and check. If still the same, you can be sure the barrels and pistons are fine, problem will be the rods wrongly resized(if they have been reconditioned before), crank ground slightly offset or the case surface has been machined incorrectly/worn due to loose heads. You can check the case and if you don't see any barrel marks, chances are it has never been machined, so my bet would be the rods all else being ok. On the AA pistons and barrels i found to have differences never more than 0.05mm, but you never know. 4- More than 7.5:1 will contribute for a slightly hotter running engine; you will already produce more heat with the 1641 pistons; 7.7 should be fine but if you preffer more reliability than to extract every single bhp you can from the engine, 7.3 would be your best bet IMHO. Abel [/QUOTE]
Verification
Post reply
EarlyBay Forums
Technical
Deck Height - One Cylinder is different, is this okay? Plus 7.3 compression ratio?
Top