had a turbo motor that was supposedly rebuilt when purchased. i ran it for a little while then had a little tooooo much fuel and had a large backfire. after that it started burning a small amount of oil. i pulled off the exhaust manifold and saw that oil was covering the exhaust sleeve of the rear rotor. after pulling apart the motor i've checked tolerances on everything and the only culprits would be the outer oil control spring of the front side of the rear rotor or this crack on the rotor.... i have purchased new oil control ring springs, trays, and o-rings, and assume this would fix the problem until realizing the crack on the rotor. i was wondering if this could also be the reason why it leaked oil.

if you look at the picture, you can see the crack. would oil seep through the inside of the rotor and out this? and cause it to burn oil?


the crack is pretty visible and my fingernail catches on it. the crack is on the top right part of the rotor... right above the oil control ring location and above the 4 as seen in the second picture.

my dilemma is that these rotors have been milled for 3mm apex seals. I have another s5 t2 rotor that is 2mm but i called a bunch of places and most wouldn't want to mill rotors for 3mm apex seals and pineappleracing only does it for a set. I have a blown s5 t2 motor that i can pull apart... and if worse comes to worse I hope both rotors are the same weight and i just run 2mm apex seals.

so if anybody knows of any shops that mill for 3mm apex seals... that'd be great to know as well

 

does anybody know the thickness of this part of the rotor?

 

I have a question..

Why cant you use 2mm seals?

 

Its milled for 3mm. so u cant use 2mm.

and 3mm seals will resist pinging better ...

hmm ... if Im seeing it right hmm ... that part you might be able to have someone to "lighten" it for you, it will scratch that whole area out. might be able to save the rotor this way plus u have lighter rotor.

 

i can use 2mm apex seals as i have one good rotor with 2mm apex seals and a blown s5 motor that has 1 good rotor in it.... but that will require me purchasing new apex seals which will run me about 300 and i'll have to purchase the corner seals, which will cost me another 72... so 372 total. milling a pair of rotors for 3mm apex seals from pineappleracing will cost 350... so i'm really hoping that this rotor is re-useable. I'm going to test it by placing gasoline inside the rotor in this area and see if it seeps out of the hole.


you can see how the crack is on both sides of the rotor... meaning left and right sides on the picture. what would happen if i left the rotor how it is and installed it and ran it? would it create a hot spot? or burn oil that seeps in between the crack?

 

As you know that the rotor is oil filled. Your engine oil is pressurized upwards of 100psi, so even if the gas doesn't seep thru the crack it still will cause oil to seep out of the rotor and into the combustion chamber. I would not reuse that rotor in an engine, you can make a nice clock out of it

 

I have looked at those pics and I cant seem to find the crack you speak off...

 

It is about an 1/8" above the "4" and runs from the outside of the rotor face to nearly the center of the rotor. I had to look hard to see it also.

 

can you take a ligh sand paper and brush the dirt off it? I can see the crack but it looks more like an oil mark

 

If in fact that's a crack, don't re-use it, but it looks more like a scratch to me in the pictures.

 

sorry about the picture. i tried to get as clear as a photo as possible. you can see where i tried rubbing my finger over the crack... it's where there's the oil smeared on the rotor. I'm beginning to think this is the reason why the motor started burning oil. I looked on the irons and there are no scratch marks where the rotor would come in contact with the iron.

it's hard to tell if it's a crack or a really deep scratch... but i wouldn't think that the rotor would scratch so easily... especially over half of the rotor and the side seal groove.

so if it is just a scratch... is it still possible to use it? or will it ruin the iron?



and i'm coming to the conclusion i should just use my other rotors that use 2mm apex seals... I'm planning on going with the cryogenically treated apex seals from atkins but does anybody have any input on these? they go for about 270 while OEM seals from pineappleracing cost 360. and would you recommend the solid corner seals over the ones with the plugs?

and once again... thanks for the input guys. you've been a great help ending my frustrations at my seemingly unending engine rebuild.

 

well to conclude the story, i opened my other blown turbo block and found that the rotor was indeed a "D" weight rotor so I'm using 2 D weight rotors that are just stock 2mm rotors. so i'm just one step closer to finishing my project. thanks for the help guys

 

Good choice. A cracked rotor, if it decides to fail completely, would cause major internal damage. Now you just have to tune more carfully with the 2 mm seals.

 

hey if the rotor is rusted could i sand blasted it to remove the rust??? or would it mess it up??? would like to know cause i like rebulid a 13btt,,, pm me.... thanxz...

 

Buy some 2mm Als seals or 2mm RA super seals and you wont regret it over the 3mm apex seals.

 

How rusted? Sand blasting you have to be very careful because it is difficult to get all the sand out.

 

NO dont sand blast any part of the motor or any motor for that matter. I soak the engine parts in kerosene over night then use a wire wheel to remove rust or grease.

 

ok thanxz.... and i can do that to all the motor parts.... and wont harm the proformance??? cause i get one 13btt to rebuild and its rusty.... and where can i get som cheap apex seals there dollors....

 

If you were willing to put some time into it - you could save a rotor for future use determine if it's a crack or a scratch by cleaning the area up (remove the scratch/crack by the best fit method) and do a dye-penetrant test. Not too difficult to do and will give you a definite answer.