Guys with a compression test result of R 88 86 89 @256RPMS.
F 88 86 86 @256RPMS.

When can I expect to have to rebuild ? Be gentle with my soul

 

It's low. FSM says it should be about 100 psi at about that rpm. The good news is, the numbers are even across all faces and both rotors.
When should you expect a rebuild? I wouldn't worry about it until you begin having hard hot starts. More good news, you have some time to save up...maybe get thru this driving season and do it...get it scheduled into someplace like IR Performance which can't be too far away.

 

Thanks for the info ... I guess my paint job will have to wait 😣

 

For what it's worth my potentially original engine at 237k miles has a beastly ~70PSI F/R across all faces and doesn't have any problems, besides the obvious lack of performance. So like Sgtblue said, you have some time.

 

People put a lot of stock into compression tests however at best they are an educated guess unless the Mazda tester is used.

Those numbers are a little on the low side but I wouldn't worry at all. They are even, which is what matters. As long as the engine runs fine then just enjoy the car.

 

why wouldn't they? too many people around here also tend to waste lots of time and money on cars with blown engines. low compression on single or dual faces could point out an issue that could cause damage to destroy costly parts of the engine. sometimes i feel not enough importance is put on compression tests.

 

^Because, as Aaron and I both mentioned, the numbers were even across all faces and both rotors. And as you alluded, if one had a hard seal failure that wouldn't be the case. And while anything is possible, I don't think the chance of a catastrophic failure that could cause more damage is significantly increased.
Pulling an engine for low compression without any other drivability problems is silly...IMO.

 

specifically speaking yes, but my response was more a general response, so that people don't read into it thinking that anything over 70psi might mean they are ok to shoot 30psi of boost through their engine. it really bothers me when people ignore compression tests when they give you all the information you might need from your engine. moreso you see lots of people running around in circles, almost intentionally avoiding doing a compression test.

in this case, yeah a steady ~85psi figure doesn't mean the engine is going to quit due to a major issue. it is usually inconsistent readings that point to major issues.

for reference, my last motor was down to about 45psi on both rotor faces before it finally refused to start, but the readings were even across the board and it still was fine with the 16psi of boost i ran through it. but with a standalone you can adjust cranking maps, it is the stock cars that easily flood with such low compression figures.

 

Drive it til it Pukes!..That is why you bought it isn't it?...To drive it?

 

There is a big difference between a blown engine and a slightly low compression test.