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TR4/4A TR4a engine compression


Does anyone have answer to cylinder pressures; it will be appreciated.
My Tr runs great at all speeds, except for my continuing problem with strong fuel smell and maybe fuel mixture adjustment. But my question today is :
1. I pressure tested all cylinders, just to know the answer . All four fell within 149-150 psi. Is this normal for piston/rings with 50,000 miles. If not , what should it be?
2. I do not see the answer in my car manual, except that under Performance Data it shows: 100HP @ 4600 RPM; Torque, 1520 psi at 3350 rpm ( equivalent to 145 psi BMEP).
3. Is the above 145 psi my answer...I figured No! What does BMEP mean?
Thanks for any information.


Jedi Knight
Brake Mean Effective Pressure. Which isn't much help is it? Your compression readings are good in that they are so consistent across all four cylinders. I don't know if there is a factory recommendation or not, but 150 sounds pretty good.


Great Pumpkin - R.I.P
As noted, the actual pressure reading isn't so important; just the comparison between them. All between 149-150 is outstanding, much better than I would expect after 50,000 miles.

BMEP has basically nothing to do with compression gauge readings; it's just measured torque divided by displacement (with suitable scaling to psi).


Country flag
As the others have said the compression readings are great, good number, great consistency, means your rings and valves are doing what they are supposed to do.

The gas smell, if there is a way out gas will find it, if coming from the back check the sending unit on the top of the tank, and fuel line running to the carbs (you will need to take the back panel out of the trunk for the sending unit, and get under the car for the fuel lines)

If from the front should be either the lines or the carbs. Could be pump, lines from tank to pump to carbs, carbs, includnig overflowing float bowls or leaky float bowls. Do you have SU or Stromberg carbs?


Thanks for the responses.
I have Stromberg Carb. And there are no signs of fuel leakage on the carbs, only fuel smell after running the car, and two hours after! Neither can I find fuel leaking or fuel wet spots anywhere , from the tanks to the Carbs or anywhere in between. Yes, I did inspect the fuel float area into the tank.

Have not disassembled carbs to check carb float level as I considered it impossible for internal float valve overflow to cause the smell..or am I wrong? If wrong, and have nothing else to check, SO, should I tear into the carbs?

About BMEP, thanks to all. I should not have asked , but googled instead , as I do other things.


Country flag
I wouldn't just tear into the carbs, no, but you could remove the air cleaner or whatever you have to do to see inside the carb's mouth.
The jet extends down into the float chamber and if the carbs were overflowing due to the needle valve or floats in the float chamber, I'd think the excess gas would show up first pooling on the bridge, where the metering needle enters the jet.


Thanks poolboy,
I have been running w/o air filters to quickly inspect if fuel pools as you described, but the bridge/needle junction looks clean immediately after parking.
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