Hi,

Im currently trying to save an NA 6port FC. The car came with 2 engines, 1 was already stripped down by myself as it was full of rust.

I just tested the other one, using a compression tester with the schrader valve removed.


Front rotor is giving me a an even 3x 100 psi pulse

The rear one however is inconsistant, some turns i get 90-90-80psi, but im also seeing 90-90-65psi. What could cause this?

Test was done with some oil in the chambers, cold motor didn't run for 2 years.


This engine is a temporary solution, car hasn't been on the road since 1996. So im not caring to much about this engine. Just wondering if this would start and run, so i can test the car and get it road legal. (im from europe). Engine will be swapped with a rebuild later.

 

Based on your description of the inconsistent third compression reading on that rear rotor, it appears to me that there is a sticky side seal on either side of that particular rotor face that is giving the low reading. I would suggest spraying a decarbonising chemical such as "Sea Foam" through the leading spark plug hole, and onto each face of that rear rotor,(since it is not known which rotor face has the sticky side seal). This entails spraying a liberal amount and turning the eccentric shaft in order to fully coat the entire surface of each rotor face. Some members have squirted automatic transmission fluid through the spark plug hole, thus coating the entire rotor and letting it soak for days, with good results. Another product that would also work well would be "Marvel Mystery Oil", but I'm not sure if that is available in Europe. I have examined the fit of the side seals into their grooves and have noticed that they do have a close fit, so carbon buildup could definitely cause them to stick and not apply even, constant pressure against the side housing, resulting in some compression loss.

 

Thats good news, i hope this engine while i save up for the other engines rebuild.

Seafoam and Marvel mystery oil is available here