Universal 5424 Compression Test

[Obi Wan]

OK, time to decide whether or not to tear into my Universal or just take care of the outside. I ran a dry compression test and came up with (front to back): 250, 250, 275. Seems kind of low. Can't find any info in the manual on proper readings.

[Obi Wan]

I just found this:
http://www.engineprofessional.com/TB/TB030915-1.pdf

and with their advice did a wet compression test with 10cc's of oil each and got:

350, 330, 340

[Obi Wan]

And that was a mis-type - it was 1 cc of oil.

[lonesoldier0408]

250, 250, 275 then 350, 330, 340. 10 psi between cylinders is one thing. I'm assuming the second readings were taken in reverse order, as they show within the same general 75 psi to 90 psi increase on each. However that's a 20 psi difference between the best and worst performing cylinders. That much deviation, begs the question, why? Rings stuck in the ring groves, damaged ring land, pitting from salt water egress and left in the cylinders. Fair wear and tear window should be more even.

[Obi Wan]

No, those are the same order. I don't have huge faith in the accuracy of the tester gage. The width of the needle is 10 psi.

[lonesoldier0408]

Ok, 100 psi change on #1, 80 psi change on #2, 65 psi change on #3. Again 65 psi to 100 psi is a large variation. Just my 2 cents, worth what you paid for it. Fair Winds. Run test with another compression tester.

[Cheechako]

Was it a compression gauge on a fitting? or hand held? Hand held not sufficient for Diesel engines I've been told.

[lonesoldier0408]

Originally Posted by Cheechako

Was it a compression gauge on a fitting? or hand held? Hand held not sufficient for Diesel engines I've been told.

I Second this.

[SV Bacchus]

Originally Posted by lonesoldier0408

I Second this.

Yup, got a third on it!

[Sputnik]

Hi,
The best and most informative way to test your engine is with a Cylinder leak test. Via the injector port or the preheater port you apply compressed air to the cylinder with the piston exactly at TDC, both valves closed. This will show where the air is leaking to: Valves or past the piston rings. This is a cheapish tester:

Cylinder Leak Tester Petrol Engine Compression Leakage Leakdown Detector Kit UK | eBay

Clearly you will need a compressor, a small compressor again is not too expensive, hopefully you have access to mains power to drive it?

It is possible to check bore wear further down the bore by having a very long bar on a socket to turn the crank away from TDC, but hold tight!!

Neil