[Mk2] [NA] Different Compression Readings across cylinders 1-4

[pjeff18]

Hello everyone

Having been out dragged at Snetterton a couple of weeks ago by another rev3 engined MR2 i decided to check compression across the engine. The results were:

From Right (1) to left (4) - left being where the airbox is

Cyl 1 = 170 Psi 2= 155 Psi 3= 180 Psi 4= 160Psi

Just wondering what your thoughts and recommendations would be in terms of where to go now.

A bit of further info:
Engine does not burn or use Oil
Sounds sweet
Pulls well (not as well as that other one though)

There is clearly some difference between readings - I know that anything more that 14psi should be investigated.

Whats the best way of checking valves without removing the head - is there any?

[3S Service Centre]

You should be able to rule out certain issues in the process of doing the leak test.

When I see funny readings I get some hose and poke it down the intake runners, listening for a different in air rushing past the valves in the intake runners can indicate a carbed up set of valves.

There are other simialr tests you can carry out in the leak test process.

Its probably fine, if it was getting past the rings you would be burning oil and running down on power.

James

[bobhatton]

Re do the test again but this time put a small amount of oil in each cylinder before checking it. This will help to seal the rings if they are leaking and give a better reading. If the readings are the same then it will be your valves.

Bob

[3S Service Centre]

or headgasket

[pjeff18]

Thanks Guys,I am going to first do the oil test and see what the compression is like after that.

Would the above figures cause substantial power loss?