View Full Version : TR6 TR6 Compression readings

04-08-2006, 08:39 AM
when doing a compression check on a TR6, does any one know what the normal readings should be? 1971 year

04-08-2006, 08:48 AM
My TR250 runs around 180-190 PSI. This probably a bit above stock though. When checking compression, remember to keep the throttle open so as to get an accurate reading.

Andrew Mace
04-08-2006, 10:19 AM
Right. And warm the motor first, and do it with all the spark plugs out. I don't know what normal readings should be, either, but I'll guess somewhere between 110-140; more importantly, they should be ideally within 5-10% of each other.

04-08-2006, 10:50 AM
Compression gauges can vary a great deal. As Andy pointed out, it's more important that all cylinders test out fairly close to one another.

04-08-2006, 11:06 AM
Just checked all cylinders
#1 180
#2 185
#3 180
#4 185
#5 187
#6 185

I still have not found anywhere in the Haynes manual at to what is should be, I must have the HC head, all number look pretty good

04-08-2006, 11:09 AM
I'd say those numbers look just fine. The biggest difference is 180 to 187, which is less than 4%.

04-08-2006, 06:41 PM
I was looking in the Bentley service manual where it gives instructions on how to check cylinder pressures. It didn't say anything about opening the throttle wide. It just said to warm the engine up and remove all spark plugs. Just curious where the thought of having the throttle wide open came from and what effect it might have on the results. BTW it doesn't give any values. Just says all cylinders should be within 10 lbs of each other.

04-08-2006, 09:07 PM
If closed, the carb butterflies could potentially mask an intake valve leak - resulting is a false (higher) pressure reading.