gcoop77c

I've been trying to do some research on rebuilding my 85'. I ran across the synthetic oil in the FAQ page. It said it was bad because of not burning. My question is what kind of problems would it create exactly. I had been told when I bought my car 10 years ago that it had synthetic oil run in it and that it was bad to go back to regular oil after synthetic had been run. I new absolutely nothing about rotaries at the time so I went with what I was told. Now I'm wanting to rebuild and don't know exactly what all I will need as far as parts, and would the use of synthetic cause any additional parts that a normal rebuild would not?
I'm currently overseas in Iraq and I'm wanting to start buying some parts so I can do the work when I get back. I'd really appreciate any help I can get as I have not been able to find anything more through the searches.

smnc

Oh GOD! Here we go again!

Alright, imo, and many others (including many engine builders and race teams) there is nothing wrong with runnign modern synth oils in your rotary.

In almost as many others, the opinion is that of Mazda 20 years ago, that synth is bad, and will leave a lot of carbon build-up in your engine.

As for not switching back from synth to conventional, I can't imagine why...?

Okay, so if you want to play it safe, here's my advice:
1.)Do a complete oil change and get some Idemitsu Rotary synthetic
http://www.idemitsu-usa.com/page_211.htm
It's synth designed for rotaries.
2.)Run a full can of seafoam through the gastank to clean out any existing deposits.

gcoop77c

What I had read was the Mazdatrix FAQ page. I guess what I'm trying to ask is it said that the synthetic oil could cause the seals to stick. This I guess would cause the loss of compression I had. The motor was also overheating? I could put some oil in the carburetor to get the compression up to start the car, but it would quickly overheat. Would this indicate that all I've needed all this time would be to replace the seals? Or could there be some other problem involved?

Rogue_Wulff

Some early synthetics did not work well in the rotary engines, due to the oil injection system, and would actually gum up the apex seals. This is why they were not reccomended for use. Newer synthetics have solved this issue, generally speaking.
As for switching back from syn to regular oil, it was bad with some early synth's, but modern syth's are fully compatible with regular oil, and can be topped up with it, if needed.
As for what may need to be replaced in your engine, impossible to know without details about what occured, when it died. Give us some details, and perhaps we can render a guess about what happened to it.

gcoop77c

What I had read was the Mazdatrix FAQ page. I guess what I'm trying to ask is it said that the synthetic oil could cause the seals to stick. This I guess would cause the loss of compression I had. The motor was also overheating? I could put some oil in the carburetor to get the compression up to start the car, but it would quickly overheat. Would this indicate that all I've needed all this time would be to replace the seals? Or could there be some other problem involved?

gcoop77c

sorry I was trying to edit what I had said when you replied?, hopefully that gives a little better explanation of my question/problem.

smnc

"Replacing the seals" involves a full rebuild.
You may very well have come carbon build-up in your engine. Run some seafoam in your gastank to clear it up.

gcoop77c

It wouldn't run the last time I tried to start it, which was back in about 97'. It would overheat and just stop running. That's what made me think I needed to rebuild. I had talked to a Rotary performance shop back then, they said I needed a new engine and quoted me a 2500 price tag so there it's sat ever since. Now I really want to bring it back.

Rogue_Wulff

Well, the low compression could be nothing more than the apex seals sticking, from the carbon buildup. The overheating is another matter, though. Once a rotary has been overheated, it usually needs rebuilt. The coolant seals between the housings tend to leak after the motor has overheated.
Without the overheating issue, it could be possible decarbon the engine, thereby adding new life. With the overheating issue added to it, you are likely looking at needing to rebuild it, especially if any coolant is disappearing, and not showing any signs of where it's leaking from.
Rebuilds can run from under $1000, up to over $3500. Depends on who does it, and what needs replaced. Of course, it also depends on which engine you have. You listed it as an '85, there were 2 engines used that year. 12a or 13b?
Another option is buying a used engine. 12a's can be found in good condition on a regular basis, due to being pulled for an engine swap. Often, they can be bought for very little.

gcoop77c

I don't remember any coolant problems really. When it started overheating I replaced the thermostat, flushed the radiator, even replaced the water pump(thinking that might be the problem) When I talked to the rotary performance people they said what I had was the equivalent of a warped head, which didn't make any since to me. I think I have a 12A, I was reading that if it was a 13B it would've been fuel injected. Mine is not. I can't really check until I get home. I thought of getting another engine. Now I'm trying to weigh my options. They don't pay soldiers much and I'm on a limited budget.

smnc

If they said you have the equivilant to a warped head, then they think you blew out a water seal. Rebuild time!

To double check, turn the engine over a few times and check the sparkplugs for water.

Also, try cranking the engine with the rad cap off and have someone look for air bubbles.

You'll also want to do a compession check.

gcoop77c

I haven't read anything about replacing a water seal, Does that mean that the other seals could be good or would they need replacing as well.

Rogue_Wulff

If carbed, it likely is the 12a. The 13b was fuel injected, but many have been converted to a carb. Good used 12a's can be found for as low as $300. The lowest price I have seen for a rebuild on a 12a was $700 if you pull and install. Of course, that price was just for the typical engine, that did not need any major parts replaced. Bad housings or rotors can cause the price to climb much higher.
I fully understand the low pay. No where near enough for the risk you guys are subjected to.

gcoop77c

Well, I appreciate the support about the pay thing, it really isn't much. I make now in a month what I made in a week before I came in. Should've rebuilt the thing then. I had thought about another engine, but was afraid I may swap it out then have some problem with it, and then would need a rebuild anyway. I had spoke with JCloud about getting one from him, but couldn't find anyone to pick it up. I'm hoping I don't have any major problems except for the seals. I'll have to do some research on the water seal. The other's seemed pretty cheap. I can stumble my way thru doing the rebuild I think. I was just hoping for a cheap fix.

Rogue_Wulff

It's still possible that your current engine is still able to be fixed, without investing a lot of money. The big unknown is the coolants seals. It really boils down to just how hot it got, when you had the overheating problem. If it actually boiled over, they're likely toast. If you saw that it was heating up, and shut it down, they may not have suffered.
If the overheating issue can be solved, getting compression back up to a usable level is possible, especially if it is carbon buildup causing the trouble.
At any rate, I wish you the best of luck. Both in Iraq, and in getting your car back on the road.
Once you are back home, and have the time to tinker with it, feel free to ask questions. There are many people that visit, who will be very helpful when you need it.

gcoop77c

Well, I appreciate the help. I'll actually be coming back to Lawton, OK after the 1st of the year. My car is down in Dallas though. It gives me some food for thought. I'm really wanting to get back there and start tearing into it. I may still get another engine and then mess with rebuilding as a spare. I'll look forward to getting it fixed so I can get on the road.

$100T2

iTrader: (1)

What's the collective opinion on putting Slick 50 into the motor?

smnc

I think I can safely speak for the majority of folks here when I say:
Slick50 is snake oil, and not worth the bottle it comes in...

Rogue_Wulff

Much milder than I would have been.....
Better way to waste $10, flush it down the toilet. That way, you are at least entertained for a bit.

$100T2

iTrader: (1)

Ah. I have never tried it, always been curious... Well, that answers that.

smnc

Np...
Aparently (according to foum lore) it once was a quality product, but was then bought out...

Hyper4mance2k

iTrader: (40)

synthetic = good... unless you still have your MOP... And yes its a metering oil pump, look it up it's not an, OMP...