Checking compression on a deisel
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=175091
Printed Date: 17 Aug 2025 at 11:33pm
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Topic: Checking compression on a deisel
Posted By: ksbowman
Subject: Checking compression on a deisel
Date Posted: 11 Oct 2020 at 9:21pm
| Hate to post this but, I want some direction. Let me say I've done nearly all my own mechanic work my whole life. It's always been on gas engines though. I've overhauled several car motors and balance and blueprinted a couple so, I'm not a rookie. I have a 170D and I need to run a compression test to track down a problem. Do I need to fabricate or buy an adapter plate to bolt on with an injector jig for checking the compression? Or is there an easier way? Any help explaining to this 70 yo would be greatly appreciated. |
Replies:
Posted By: DrAllis
Date Posted: 11 Oct 2020 at 9:32pm
| Injectors have to be removed and find (or make) an adapter to go in place of the injector body and connect it to a compression tester with a 600 psi gauge. |
Posted By: ksbowman
Date Posted: 11 Oct 2020 at 9:38pm
| Thanks Doctor. That's what I assumed. If I could get one where would be the best place to look? Maybe a retiring mechanic I bet. Probably an elusive critter to find. Also Doc, Do Lancaster Balancers go bad often? Have you ever had one that had problems? |
Posted By: DrAllis
Date Posted: 11 Oct 2020 at 9:47pm
| Never had one of those balancers go bad, but I never had many Perkins diesels either. Most of my units were larger in diesel form. An old injector assembly with the guts removed and the nozzle tip sac ground off is a test adapter if you can get it to connect to your gauge. |
Posted By: DiyDave
Date Posted: 12 Oct 2020 at 4:27am
Does a 170 have individual glow plugs? If so, there are diesel compression gauges that go in through the GP hole...
------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: DrAllis
Date Posted: 12 Oct 2020 at 6:27am
| Those Perkins engines to not. |
Posted By: injpumpEd
Date Posted: 12 Oct 2020 at 8:51am
|
Harbor freight has nice low cost diesel compression testers, but get the bigger set for this perkins. ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: Brian Jasper co. Ia
Date Posted: 12 Oct 2020 at 11:32pm
|
I have a Star Products gauge from the Snap On Industrial catalog. Comparable quality to Snap On without the full Snap On price. It depends on the engine as to whether they test through a glow plug or injector hole, but in this case it's through the injector hole as the Dr says. ------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: wide
Date Posted: 13 Oct 2020 at 11:23pm
|
On the VW diesels I work on turning the engine over by hand gives me a good idea what the compression is. I don't have to worry about the change in volume due to the injectors or glow plugs being removed or volume of the injector tester being added to the volume of the cylinders. That said, I'm sure it's easier to turn a 1.6 or 1.9 diesel by hand than it is a AC 170 diesel. |