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The mkiv Supra Owners Club

Oil pump (crankshaft front) oil seal failures


Chris Wilson

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Update on PRV spring/s just received my oil seal and springs, yes there are two despite only one being listed on the EPC and manual.

 

0.37 liters per second:(

 

If thats the worst case scenario, then even a 1/4 of that is going to fill and pressurize the small gallery between pump rear and seal pretty quickly.

 

Here is a pic of the front of the pump, not very good but you get the idea, what is not visible is the area behind the seal, i will post a pic of this when i remove my seal later.

http://www.imagestation.com/picture/sraid225/pc33ec937616b4b1e765a5e2c23786f04/e9bf8e6e.jpg

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Just to butt in with a bit of history on this particular car that Chris is talking about which might be relevant (it's mine by the way :) ).

 

4 months ago it had a crankshaft pulley damper fitted. This was after the old one had separated into two pieces (I found the outer ring of the damper lying on the undertray by chance when I was tracking down a rattle in the Cat heat-shield). The belt was running on what was left of the damper and there was no indication when driving that anything was wrong.

 

I don't have any technical knowledge of this subject, other than what's in this thread, but is it possible that the disturbance of the outer ring falling off and the belt then pulling what's left of the damper has disturbed either the seal or the retaining spring because of uncancelled vibration in the shaft?

 

Probably irrelevent, but it just gives a bit more background that might be useful. :search:

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Well fitted my new seal and put it all back together today, also changed the oil back to 5W 30, haven't had a chance to drive it yet as my bloody back is bad:( hopefully tomorrow, going to be a little hesitant for a bit but i still need to set my boost up, i am also going to attach my peak hold boost gauge via tube to the dip stick tube just to see if and what pressure/vacume i get, just out of interest, although i am 98% sure its oil pressure related,

if the dam thing goes again, i think i'll pay someone to take out the oil pump and check it and open out the drain hole, i have also made an inquiry at a local bearing suppler as to whether there is an uprated version of the seal that will handle more pressure before letting go.

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Very interesting thread.

The FMS issue is still open.

Several theories, both here and on Supraforums, no definite answer yet.

 

I'd wonder, has the seal gone south in an engine with demonstrably low blowby? (something we know positively, not just 'it didnt smoke so I guess it was OK')

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Very interesting thread.

The FMS issue is still open.

Several theories, both here and on Supraforums, no definite answer yet.

 

I'd wonder, has the seal gone south in an engine with demonstrably low blowby? (something we know positively, not just 'it didnt smoke so I guess it was OK')

 

Will let you know when i get to drive mine, back is stll fooked:(

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OK finally got to drive the Supra today, didn't push it, about 0.95 bar and probably no more that 5500 RPM, and the seal is holding, its high RPM that i'm concerned about as this is where oil pressure is at the highest.

I also did a test on the any crank case pressure with a peak hold boost gauge, and the result was 0 maybe slight vac, but no problems, so i guess that categorically rules out any pressure problems on my engine.

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I gave Mikes car a good hard run from cold, full boost for ages, against the brakes, up a hill, and up to the rev limiter, several times, with no problems. He also got back from here to Devon (I think it was Devon) with no issues. So for now a new seal has fixed things. There was no more end float than well within spec, so it's not a crank end float issue, either.

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Yes please! Has it been apart yet? Any other engine problems on this pump? Thanks Kev.

 

This is the pump from the engine we spoke about today Chris. Looks like oil starvation on the engine. I can either post it to you or pop it up when I pick the other stuff up from you. No it hasn't been apart. :)

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I get 117 PSI at idle from cold on 5W 30, Christ knows what it would be at 6,000 RPM:( although hopefully the PRV would be active well before then, i would still like to find out at what pressure it should start to open?

 

Load on PRV springs at full closed in pounds times surface area of PRV piston orifice in square inches.

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