Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Tractor Pulling Discussion Forum

compression lbs. ver. comp. ratio ????? HELP

Welcome Guest, Log in or Register
Author 
1morgan

10-20-2005 18:38:29




Report to Moderator

If comp. was 250 lbs. what would the ratio be ? THANKS FOR ANY INFO.




[Log in to Reply]   [No Email]
buickanddeere

10-23-2005 06:21:01




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to 1morgan, 10-20-2005 18:38:29  
Cranking rpm, air temp, humidity, valve timing and volumetric efficiency are all factors that must be considered.



[Log in to Reply]  [No Email]
jd b puller

10-23-2005 14:17:02




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to buickanddeere, 10-23-2005 06:21:01  
B&D - is it reasonable to ESTIMATE about 20 PSI per CR? just to get you in the ballpark?



[Log in to Reply]  [No Email]
Drew

10-23-2005 15:40:16




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to jd b puller, 10-23-2005 14:17:02  
Not really. On my tractor a few years ago, the head/manifold/carb was changed, dropped THREE compression points.....ended up w/ the same cranking psi. There is NO way to compare cranking psi to mechanical comp. ratio.



[Log in to Reply]  [No Email]
Rahlo

10-23-2005 19:42:32




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to Drew, 10-23-2005 15:40:16  
Drew, you hit the nail on the head. I have been a mech and eng builder for over 20 yrs and I get the same ? put to me. I get a lot of odd looks when I tell people that I have seen 6 to 1 engines pump 250psi and I've seen 10 & 11 to 1 engines pump 225psi. You cannot compare the 2 comp ratio and PSI.



[Log in to Reply]  [No Email]
psi

10-21-2005 11:13:21




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to 1morgan, 10-20-2005 18:38:29  
psi isn't relevant to ratio. to get a ratio, you need to CC your motor. just do a compression check and see how many psi you have. depending mainly on your bore and head design, you can tell how many octane you would need to run. if it was a moline with a 5" bore and 200lbs of compression, you could run it on 94. if it was a JD A or G with a 6.125" bore, and 200lbs of compression, you would need 105 or more octane to run it.

[Log in to Reply]  [No Email]
Rahlo

10-23-2005 19:58:51




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to psi , 10-21-2005 11:13:21  
I'll have to dispute your theory on that. You need the compression ratio still to burn the higher octane fuel. If you have a 6.5" bore or a 3" bore it will make no differance, if both engines are 6 to 1 compression you still need lower octane fuel just a larged fuel charge in the larger bore engine per cylinder. If the 3" bore engine was 10 to 1 you need higher octane to produce a slower ignition and a longer burn time.

[Log in to Reply]  [No Email]
BM

10-24-2005 19:36:56




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to Rahlo, 10-23-2005 19:58:51  
Don't forget, combustion chamber shape and quench area make a big impact on what octane rating you can run.



[Log in to Reply]  [No Email]
psi

10-25-2005 11:31:07




Report to Moderator
 Re: compression lbs. ver. comp. ratio ????? HELP in reply to BM, 10-24-2005 19:36:56  
exactly..thanks BM



[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy