Hi I just bought a core engine with tranny harness etc knowing it had low compression on front rotor. So my front rotor has like 100,50,50 and the rear has 100,100,100 so the engine basically sat for like 4 months. The engine was advertised for like 1000 but he did a compression check like 4 months later and the compression dropped on the front rotor so could it possibly be a seized apex seal,corner seal, or side seal being that it sat for 4 months.
Thanks

 

Yes.

Whatever is wrong with it, it's going to need a rebuild. Dig in!

 

Yeah thats what I am going to do I plan on taking it apart hopefully tomorrow.
Thanks

 

Are you saying the motor sat for 4 months and then lost compression, or was it running and when he initially tested it the compression was good, then it went down before the motor was pulled? If it lost compression while sitting, a seal might have stuck. Put a liberal amount of atf down each intake runner or each spark plug hole. Turn the motor over a few times. Let it sit a few hours, then repeat the procedure a few times. You might have a chance of unsticking it.

 

Yeah the engine was sitting with good compression then lost it for some reason. Like I said above the engine had 100,50,50 so the apex seal that is getting 100 means that the housing is still good so that is why I think the engine has a stuck seal because if a apex seal did let go the 100 psi would not be there. Also the rear rotor has 100,100,100 psi so the housing are worn probably the same. Btw how harsh is atf on the oil control ring seals.
Thanks
Richard

 

I wouldn't assume the motor had good compression before it sat. I would just assume it's blown unless it has good compression now. Unless you really know the person, their account of the engine's past is likely not accurate.

 

Its fine. Some people even use it when installing the oil control rings.

 

Yeah I agree mahjik but I am going to try the atf treatment just to see what happens. But I am going to do a rebuild anyways.
Thanks
Richard

 

Just an update I did not get the engine taken a part but I did get a look through exhaust port and there is a lot of carbon in the front rotor that has the compression issue also when I pushed on the apex seal I can not even feel them push inwards, the rear rotor does not have a lot of carbon like the front. But I am still going to take engine apart fully tomorrow. BTW when I get the car up and running I have to go through an emission check so my question is can I have a nice street port and still pass.
Thanks
Richard

 

Hi it turns out the engine that I got is a mazda reman is there any way to look up the numbers on the tag to figure out when it was bought or installed.
Thanks

 

A mild port should still pass emissions. The key is not to induce too much exhaust overlap. These cars are difficult to pass in stock form at times but if a customer wants to try I don't mess with the exhaust much. Just a mild polish. In some states like NJ the cars are old enough to register them as collector cars and they are emissions exempt. I would check with your local laws.

Try Ray Crowe at Malloy Mazda. He may be able to run the serial # off the remain.

 

Hi IRPerformance thanks for the help, btw how much power is possible on stock ports.
Thanks
Richard

 

Just finished tearing apart the engine and the corner seal is stuck and is full of carbon which is why I had compression loss. I plan on reusing all the seals and springs and get an o-ring kit and 2mm apex seals what do you guys think as the side seals are all in spec.

 

Sounds like a cheap rebuild. Maybe replace the coolant I rings while it's open? Otherwise I'd clean it up and put it back together.

 

Hi I plan on replacing all the o rings including coolant rings, compression rings, and even oil control rings gasket etc. I might re use the 3 piece apex seals just to get the engine going if every thing specs out. BTW do you guys think I need a new housing.

 

mor pips

 

one more pic

 

I think you're fine. You made 100 psi on them.

 

OK, so since I want to do this pretty cheap are corner seal springs normally reusable.

 

Yes, you can re use the seals. But will it be as good as new I doubt it. There's a lot of rotary mechanics including my old man that like to recycle parts believe it or not they have good luck with them. I myself work to hard to cut corners or cheap out.

The way I look at it, if your reusing side seals they do have a tendacy of having some blow by if not replaced. Even if there in spec! But again it might not stop the car from running. Soft seals should never be reused at all or longevity will be sacrificed.

The best way if your going to take a used motor part is put everything exactly back where it originally came from. 1,3,5 on one side of the rotor 2,4,6 on the other side etc etc.

Cleaning is key carbon free!

 

Hi Samito Built I have a organizer so I know were every thing goes but I am going to get all new o-rings including oil control ring o-rings and apex seals as I do not want to re use the 3 piece apex seals.
Thanks