Compression Testers
 

What kind of compression tester does this forum recommend?

I was reading the Arron Cake web site, and he was talking about using a common compression
gauge because the Mazda compression gauge cost too much money. But in my experience, I found
almost every compression gauge, with the exception of Snap On, reads about 30psi lower than the
actual compression.

I would normally use a percentage leak tester (PLT) to determine the engines mechanical condition. Does
this forum a PLT, if so what % is normal, and does the engine need to be warm?

Thank You


Bill M.

You can try this Link,Courtesy of Rotary Resurrection(thanks Kevin)
LINK:Rotary Resurrection home of the budget rebuild.
Statement at the end of #9 is a little harsh but your if your engine is running OK,run it til it drops!

I just bought one from harbor freight. I had to use a punch and a drill to get rid of the valve at the "cylinder end". A drill bit will spin on the little valve plunger, so you have to use the punch to mess it up bad enough that it locks it up, then drill away. The whole valve is brass. Pretty easy to do.

Than you can use it to test 3 rotor face pressure variation.

Go to Walmart Bill and get the Equus Brand Compression tester..about 35 bucks.You can take the schrader valve out.

You are using those compression gauges to only test the apex seals, right? Not the
compression.

Bill M.

apex seals are what creates the compression.They push up against the housing to seal off the air/fuel and when you roll the engine over it creates compression.
Using the tester you get a good Idea of what the internals are like,.
If you read that link I posted you can follow that to establish roughly what the condition is of the engine.You can get a reading on the tester.
If the Seals were NOT doing there job you would be able to tel that by the "poor man's test".Usually you can hear three nice solid "wooshes" of air with a healthy engine when you roll it over with plugs out.Anything less than 3 then something is definitely wrong,and you do not need a tester to hear that!
You could always pop the exhaust manifold off and check "sping-a bility"( hey!,a new word!) to the seals.
They can be seen when they roll past the exhaust port.Touch them carefully and see if they "bounce".If it is stuck then you could try the ATF or MMO trick.But honestly I do not depend on that aspect of Curing a stuck seal.it's not a 100% cure.

theres actually a forum memeber who makes them, twistedrotors. give him a shout but hes defiantly the "bearer" of bad news in for of compression numbers..