TEA-20 Compression Test ....Questions

[Walt Dickie]

I have a TEA 20-85. I acquired tractor last year and it started easy and ran with good oil pressure. I drained all fluids for winter.

I tried a compression check by spinning motor several times with the hand crank. Readings between 65-75 psi.

Question 1. Is this a reliable way of doing a compression test or do I have to turn the engine over with the starter motor or run it until it is hot??

Question 2 If this is a reliable test, what is acceptable compression??

Question 3. What is a "Wet Test"??

Thanks Walt

 

[Jerry/MT]

The correct way to run a compression test is with the engine at operating temperature and the throttle plate should be wide open and I disconnect the air cleaner from the carb inlet just in case the air cleaner is restricted some.

I have never tried to hand crank and engine to test compression but in theory it should work as long as you use the typical compression gauge that has a check valve to hold the pressure in the gauge. In th eold days people started the engine with a hand crank so I see no reason why it won't give good numbers. Certainly cranking with a starter is easier. Since you did this on a cold engine, I personally don't think the results are reliable.

Min acceptable compression on the Continentals is 85-90 psi. I would think that's also true of the Standard Engine but I'll let someone like Bob or John(UK) correct me if I'm wrong.

A wet test is a compression test run after squirting 1-2 ounces of oil in each cylinder and then measuring the compression. If you get a significant change in the compression pressures, its indicative of worn rings.

 

[Klaus]

Hello Walt.
I have a TEA. I did like jerry described. I got around 100 on all cylinders, and 125 wet. My engine is in reasonable condition.
it is quite important the engine is warm.
Good luck.
Klaus
Startup after wet compression test

 

[John (UK)]

Spin the engine over on the starter when the engine is hot and the battery fully charged, you should get 90 - 100lbs psi...John