Well first off this engine has a little over 1200 miles on the rebuild. 87 tII When I first got the engine going a couple weeks ago the oil pressure gauge didnt work then after about 500 miles it started working but the most pressure it showed was 30psi. It had a little miss to it ever since it was first started but I just played it off as a spark plug or small vac leak. Then right before I pulled it it started running like it had a blown apex right after I changed the spark plugs and put a wideband on it and did a couple pulls in second and third hitting 7psi to see what the AF's where.
As seen in the first and second picture the top and bottom rear of the intermediate iron has some blueing and scratches or something. The third picture is of the blown side seal on the rear of the rotor which didn't do any damage to the rear iron at all. The fourth picture is of the front of the rotor where half of the side seal was sticking/blown and opposite corner is blued and sort of scratched up. The fifth picture is a close up of the blueing. And the last picture is a close up of the side seal.
I am wondering what caused this type of damage. I have never seen anything like this.
Thanks in advance for advice.
Keith

 

Yeah, had that happen to one of the engines I picked up. Oil starvation. Replace the middle iron, it got so hot that it distorted the color. That sucks.

 

That was my first thought. Oil starvation, yet the bearing is perfectly fine...
Anyone else agree?

 

Well, It looks like it definately overheated, but it doesn't look as if the OMP wasn't working. No OMP or premix wouldn't do THAT.

Also, if there was starvation of oil at the eccentric shaft, you would have lost babbit on the bearings and it would probably be scarred all to hell.

It looks to me that the rotor was able to contact the side housings some (the rotor itself I mean, the seals are obviously supposed to contact the housings). What does the other rotor look like?

 

I do premix, and I know it didnt fuel cut, but it did get into the low 13's on Air Fuels when I did those pulls.
Well I haven't tore it down to the front. The front had over 90psi equally on all faces so I didnt want to tear it down.
The one pictured only had 25,25,90 so I knew it had problems, that is why I tore into it.

 

I still stick to oil starvation. Or in just lack of lube. The bearing could still be fine, and still have very minimal oil to make it run. I had an engine I picked up, that had heated up bad in the rear rotor that it cracked the middle iron.

The needle bearing has nothing to do with this, or else the front rotor would be effect as well. How's the front iron and front of the middle iron look?

^^ all just a guess. Since only oil and fuel get thrown into the engine.

 

Well I will know what the front looks like tonight. I am going to prolly just tear it down the rest of the way.

As for oil starvation, what causes it? Could the 30psi have been correct? If it was correct what causes the pressure to be low?

 

Front cover o ring, would have something to do with it. How was the oil pressure at idle? Also how was oil pressure when driving?

Also, the front half of the engine should be fine, since most of the oil make's it through the front anyways.

 

On the gauge the pressure went down to like 20-25, then anything over idle it was 30-35. I did replace that o ring and it was in place when I disassembled the engine today.
The front rotor was fine, no damage at all.
I am wondering if maybe the oil pump and or oil pressure regulator may be bad or worn out...

 

Maybe. Since there is a rear oil pressure regulator. Anything over idle should of hit 60-70psi of oil, especially over 3,000 rpm. Are you using the stock oil pressure gauge?

 

yeah tear it down.

i think the rotor gear might have come out, as the damage is on the other side. rotor and iron are junk.

fix the oil pressure gauge!

 

He did tear it down, it looks fine. So maybe my suspect is the rear spring or regulator. Take it off the rear iron and see what the spec it.

 

Yeah I think I may either buy the high pressure regulator or modify the original to do the same. What do you mean by the rear spring? How should I check the spec on my regulator?
Does anyone know of a thread or site that explains how to modify the stock regulator for more oil pressure?

 

I don't know how to modify the oil pressure regulator but, to check the regulator I believe you check the spring height to see if it's within spec. Get an haynes manual, it tells you everything about spec'ing out the engine.

 

Anyone know of an upgrade to the stock oil pump or how to modify the original oil pressure regulator?

 

I am using an fd oil pump.. (supposedlly a higher pressure pump than the t2)

 

Sounds good. I may have to look further into that...