(800) 853-2651
SHOP NOW

farmall sm

unless you are running without sleeves you won't have a 4.25" bore, stock was 4.00, most are rebuilt with the overbore kit to 4.125". If you are looking for a psi that will depend on piston design, bore dia and combustion chamber cc. Put a compression guage on it and see what you have .
 


Like has been posted already. MANY factors affect compression.(Combustion chamber CC,piston dome/dish,cam timing,cam profile,ect.)

Probably MORE important is that all cylinder PSI readings are within a small percentage of each other.
 
Compression in PSI as in a compression check, or compression RATIO?

In PSI, more is better and consistent across all cylinders is more desirable than a high compression.

IIRC you need 90PSI for an engine to run decent.

>100PSI is an engine with a lot of life left in it.

>125PSI is a good strong engine.
 
That is true Mike72. On an old tractor engine a psi that is close to even on each cylinder is a good indicator of how healthy the engine is. But, the higher the cranking compression the more likely the engine will be powerful, which is what I think he is after. In automotive, a 350 Chevy will run fine with 90 psi even compression, but if you want a motor that builds big power you will want that number much higher. Cam timing and profile can change things drastically as you stated. I have a snortin 454 BBC here that has 185 psi cranking.
 
Me too. ;)


Thread is now "high jacked" lol
a83477.jpg
 
You must log in or register to reply here.

Similar threads

K
Used My Farmall 450 Today!
Replies
2
Views
351
560Dennis
560Dennis
D
Super M will not lug at end of a tractor pull
Replies
11
Views
596
560Dennis
560Dennis
D
Super M will not lug at end of a tractor pull
Replies
6
Views
540
BarnyardEngineering
BarnyardEngineering
K
Float? Farmall 450 Hydraulics
Replies
3
Views
179
Brendon-KS
Brendon-KS
G
C264 SUPER M BLOCK
Replies
7
Views
568
caterpillar guy
C
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.

Copyright © 1997-2024 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

Back
Top