Compression test(er) for 6CTA8.3?

Does anyone have any ideas on how I can test the compression on this motor? Or if they already have some sort of tester for this purpose? Since I couldn’t borescope the motor I thought I’d try a compression test to evaluate the health of the motor as far the pistons/rings/liners goes.

Mos68x said:

Does anyone have any ideas on how I can test the compression on this motor? Or if they already have some sort of tester for this purpose? Since I couldn’t borescope the motor I thought I’d try a compression test to evaluate the health of the motor as far the pistons/rings/liners goes.

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https://www.steelsoldiers.com/showthread.php?150581-Compression-testing-M929A2-8-3-Cummins

or in short. Shut off your fuel solenoid. Disconnect fuel to injector lines. Pull all injectors. Install adapter and gauge into the injector port.

You can also force compressed air into the cylinder thru the same way to see which one is worn.

Use a leak down / compression test adapter for the 8.3L engine. It is a hollowed out injector with a removable Schrader valve in the end. Very low cost tool.

http://www.tooldiscounter.com/ItemD...MIpKay9pLW2AIVTrjACh3GAwv5EAQYBSABEgIZ-fD_BwE

From here, you quick connect your leak down or diesel compression gauge.

The injectors may be difficult to pull. Start soaking them with penetrant days before pulling them. You may need to fabricate a puller using a lever or slide hammer. I was going to try loosening the clamps and then cranking the engine over and possibly letting it fire until it pushes them loose, but never got around to it since my engine runs well. I think the fuel nut end thread of the injector is same as a common lug nut, that is what people were making pullers out of.

Mos68x said:

Does anyone have any ideas on how I can test the compression on this motor? Or if they already have some sort of tester for this purpose? Since I couldn’t borescope the motor I thought I’d try a compression test to evaluate the health of the motor as far the pistons/rings/liners goes.

Click to expand...

How does it run currently? What makes you think it has problems?


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I do have the same symptoms as idbankrman claimed in the link that simp replied with, but I wasn’t asking because of that directly. I was asking so that I could check it now and record the results and then later when I felt that I really did have a propblem I would have some older numbers to compare to. As long as I have all cylinders reading fairly close to each other then I’ll be happy enough for now. I’m hoping that my white smoking bit was because of air still being bled from any remaining pockets in the post-pump fuel system. I used both of the fuel bleed screws before th injectors to get as much out as I could, but I suspect that only a little more run time will get all the air out.

Thanks for the link, is it held in place the same way as the injectors? The picture is really fuzzy so I can’t tell for sure. Fortunately I just replaced my injectors so they won’t be too difficult to pull out again, but I’m still thinking about making the slide hammer with the M14 nut on the end.

Yes, it has milled flats on it same as the stock injectors, so uses the same retention clamp.