Construction and other equipment - ALLIS 685-T timming

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ALLIS 685-T timming

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=100674
Printed Date: 09 May 2024 at 7:38pm
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Topic: ALLIS 685-T timming

Posted By: rusty98
Subject: ALLIS 685-T timming
Date Posted: 19 Jan 2015 at 6:23pm

I HAVE A ALLIS 685T need to know how to find number 1 cylinder and top dead center of number 1 cylinder in order to install newly rebuilt injector pump. motor is a 685-t from 1980

Thank you

Replies:

Posted By: JohnCO
Date Posted: 19 Jan 2015 at 11:39pm

#1 is the closest one to the water pump. If you have the valve cover off, turn the engine over with a wrench until the timing mark shows on front pulley, it can be off 180 degrees so you need to watch the valves when the intake valve is closing, the pointer should be right at the mark. Good luck!

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"If at first you don't succeed, get a bigger hammer"
Allis Express participant

Posted By: rusty98
Date Posted: 20 Jan 2015 at 6:43am

Thanks for your input

I am an electrician trying to twist wrenches ! I am familiar with timming marks on the pulley in cars and trucks, But this allis chalmers 685-T I can't find anything. I looked hi and low. The injection pump was changed about 10 years ago and from what I can tell the valve cover closet to the water pump was not removed all the paint on the bolts is intact but the opposite end away from the water pump that valve cover was removed. That is why I wanted to clearify the number 1 cylinder.

Posted By: Lazyts
Date Posted: 20 Jan 2015 at 10:26am

The firing order on these 6's is 153624, and each cylinder has a "companion" so you can find TDC on any cylinder by taking the valve covers off and watching its companion. For example, when the exhaust valve is just closing, and the intake valve is starting to open on #6, #1 is at TDC. (this is called overlap) The valves on any cylinder can be adjusted this way- turning the engine over and watching the companion cylinder, because you know that when one is finished its exhaust stroke, its companion will be finished compression.
The timing marks should be visible on the flywheel through a small cover on injection pump side of flywheel housing- flywheel should be marked with degree lines, pump will probably be timed around 30 degrees BTDC (before top dead center). Retarding the timing slightly will make for easier starting, advancing the timing will make more power. Most 11000 engines were timed between 28 and 32 degrees BTDC.

Posted By: JohnCO
Date Posted: 20 Jan 2015 at 8:46pm

Rusty, sorry for the mis information, should have gone and looked before saying it was on the front pulley. Lazy has a lot of good info.

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"If at first you don't succeed, get a bigger hammer"
Allis Express participant

Posted By: rusty98
Date Posted: 20 Jan 2015 at 8:52pm

Thank you for the help