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How to compression test R60 & R75

katcon85

New member
Sorry, but I haven't done a compression test in a zillion years, and that was on my old TR6. I tried a search but couldn't find anything....

I have a 74 R60/6 with dyna electronic ignition. Do I have to ground the plug wires? Or do I just screw in the tester and turn the engine over with the starter button?
and I'm going to look at a 74 R75/6 with points- same question: what is the procedure, do I have to ground the plug wires?
Thanks so much-
Kat
 
Yes, I think it would be the best thing to pull the plugs, stick them back into the cap, and securely ground the plug threads to the engine. You should also pull the carbs or at a minimum prop open the slide and/or butterfly on the CV carbs. Not that difficult to just pull the carbs. Engine should have been warmed up.

I have a gage with a rubber tip so I just stick in the hole and hold it while I crank the starter. But if you have a screw in adapter, just screw it in...finger tight is probably good enough.
 
Make one of these with a good used plug. Throw it in your tool box. Comes in handy for testing, tuning and compression testing.

P1010966.jpg


In situ:

P1010968.jpg
 
Remove the carbs from the heads for the best test. Or at least hold the throttle plates wide open. If air can't get in, it can't be compressed.
 
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