Farm Equipment - 670T engine question

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670T engine question

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=209250
Printed Date: 07 Dec 2025 at 8:24am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: 670T engine question

Posted By: 8070nc
Subject: 670T engine question
Date Posted: 06 Dec 2025 at 6:22pm

Did all 670Ts with bosch injectors have the large wrist pins

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Replies:

Posted By: DrAllis
Date Posted: 06 Dec 2025 at 6:45pm

1982 was M-100 and Bosch nozzles and big pins in the 8000 series and N-series combines for sure. I think the big pin/3-ring piston thing was the fall of 1980 production?? Still a Roosa pump but Bosch injectors. It would have been at a certain eng s/n break. That's kind of how I remember it.

Posted By: 8070nc
Date Posted: 06 Dec 2025 at 8:06pm

Thanks Doc. The reason i ask is I have a 8070 that has the most blowby ive ever seen. Ive found a 670t thats affordable. I know it doesnt have the counterbalanced crank but no harder than ill use the tractor i think itll be fine. Just have to keep the rpm down to 670t level. It has bosch injectors but no injectoin pump is gone and they cut the injection lines. The stubs appear to have been to a m100 pump

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor

Posted By: Lynn Marshall
Date Posted: 07 Dec 2025 at 7:45am

Are the pump drive gear and the idler gear still in it? They are different from the M100 to the Rossa. As for blowby, I should have mentioned in the 7010 post, when these engines get coolant in the oil, they will develop what appears to be an extreme amount of blowby. The coolant will pool a little bit on the top of the head,under the rockers arms. As the temperature rises in the engine, this coolant tends to evaporate and causes a steam. When the steam comes out of the breather tube, you would swear that the rings are totally shot on the pistons. The engine may run just fine, but it sure doesn't look like it should.