Front crank seal, AGAIN!!!!

After a bit of a blast this weekend ive blown my front crank seal i think.

Symptoms are the same as the time before when this happened.

So this is twice now and im starting to get fed up of this problem.

First time was just after the engine had been rebuilt by somone else.

This time i rebuilt the engine and its been about 4000 miles since the rebuild.

Is this a common problem with supras?

Sure ive heard this before and sort of remember somone mentioning an uprated front crank seal had been developed in the States to eliminate this problem?

Any input would be much appriciated

Cheers

Scott

After doing a bit of research on MKIV.COM

Mohd A suggests doubling up the spring in the front main seal and also taking around 4mm off the springs thus tightening the seal around the crank!

Comments on this method Anyone?

Scott

He also suggested a different seal??

Heres the link

Mohd A suggestions

What sort of modifications have you got engine wise?

Stock boost, stock rev limit?

Current mods are

Full de cat

FMIC Greddy 3row

EGR removal

Boosts to 1.1 max (usually 1.05 but got just over 1.1 at the weekend without fuel cut?????)

The last rebuild included a brand new toyota short block and a new oil pump.

Scott

From what I've read (a while ago) there seems to be an unlucky assortment of engines that seem to struggle with the front main seal. Seems a lot more common in the US but probably because there's so many Supras over there. I think it may just be a bad tolerance stack up on the sealing faces and the crankshaft. A raised rev limit has been suggested as a contributor but I assume yours is stock?

I think the most information you will find on it will be SF as opposed to here purely due to numbers. Maybe give Chris Wilson a buzz and ask his opinion. It seems the installation has to be absolutely spot on to guarantee any chance even before you delve into shortening the spring/different seal etc. I have a feeling Dude also had a front seal go, have you tried him?

This has never happened on my engine (touches wood) so I cannot offer any first hand information. Any idea whether you are suffering from excessive ring blow by? Intercooler pipes oily at all? Was the car run in on reasonable grade oil to allow rings to bed in nicely before going to fully synthetic? Perhaps some larger bore breather pipes and a catch can may help if you have excessive blow by. However on a new engine if all was correct during running in I doubt it.

Sorry I can't be of any more help, but this may stir up some more replies?

Dan

theres a big thread on it on supra forums

http://www.supraforums.com/forum/showthread.php?s=&threadid=165069

sorry, yes my rev limit is stock.

I will give dude a PM and see what he did to get around the problem.

I must admit i do get blowby from my turbos (Reconditiond jobbys but not done very well obvoiusly). Theres a residue of oil in the intercooler piping but i didnt think there was a cure for that???? Apart from some new tubbys or a nice big single

( hummmmm, now theres a thought!)

I ran her in on some Castrol Mineral oil and after running in i moved on to Magnatec 10/40

Scott

A small amount of oil loss through your turbos will not be a problem to the fms.

Excessive blow by past the piston rings may well be though. But yours is a new motor and as long as you ran it in correctly you shouldn't have a problem there if all else is ok (ie not stupidly rich fuelling).

Perhaps it may be worth going for the replacement seal BH4513E as opposed to the toyota BH4513F, as this is supposed to help combat the blocking of the oil drain by the stock seal.

I hope you get it sorted, as I say I have never had it happen and am just throwing ideas up for discussion. I assume you don't hammer it until the car has warmed up properly?

Any ideas of where to get that seal from incase i do go with it?

I always without fail warm the car up and down before and after using her.

I dont very oftern give the car major stick but this weekend i did. Suppose thats why the seal has held up to now as ive not really pushed the engine to its limits since the rebuild? but i still dont push her as far as some do I,e red line etc!

Whats the max oil pressure i should be reading on my guage?

Scott

Mark:

Ive read that thread yes. Seems that they cant really make there mind up from what i can gather!

One says modify the Pump

One says use two springs in the seal

One says cut the springs

One says Dont mess and use the toyota seal!

So god Knows!!!

Scott

Sorry Scott, I can't help with either of those mate.

If it were me I'd be on the phone to CW to pick his brains about where to go next. There's lots of different opinions on this and nobody seems to have cured the problem completely. The cause may be due to tolerances in oilways in that area and in the pump itself. This could go some way to explaining why some (hard driven) cars don't have a problem and other mild bpu specs like yours do????

I personally wouldn't use two springs in either seal.

is the crank case breathing ok cus blocked breathers usually cause crank seal failure?.....

sorry to hear of your probs, with regard to doubling up the spring or shortening (tightening) i would think hard before doing this, i worked with hydraulics for about 17 years with the same kind of seals, when they went they would leave a groove in the shaft the replacement seal came with a shim to bring the seal away from the groove you could do this twice and then the shaft was knackered, if you grooved your crank that would not be good, the crank seal itself going must be a symptom of some underlying problem, dont blame the seal its fine, the only reasons i can think off is the crank not running true putting side load on the seal (unlikely as the engine would vibrate badly) or overpressure in the crankcase behind the seal, this to me MUST be the problem, like richy states if i were you i'de concentrate on the crank breathing

I think im just going to go with the stock toyota seal.

Thats what they intended to go in there and i think they must of put a lot of reaserch into this when they built the engine! More research than i could possibly do anyways!

one thing i have heard that i wouldnt mind trying is using some kind of sealand to hold the seal in a bit better. A few peeps on the SupraForums have mentioned this in the past.

But im not sure on what type of sealant to use? Any ideas anyone?

Im hoping that this is just a one off (apart from the first time but that was a different engine at the time). i will go with the stock seal again and see how it goes. If it blows again then i need to look further into the problem as it must be somthing else causing excess pressure build up.

Thanks for everyones input on this.

Scott

Also,

Anyone else have any idea on the min/max pressure readings i should be getting on my oil pressure gauge?

My defi peak hold shows that ive had just a touch over 7bar max. when cold she sits at 6bar and when fully warmed up its around 1bar

Scott

Originally posted by veilsideTT

Also,

 

Anyone else have any idea on the min/max pressure readings i should be getting on my oil pressure gauge?

 

My defi peak hold shows that ive had just a touch over 7bar max. when cold she sits at 6bar and when fully warmed up its around 1bar

 

Scott

Where have you tapped in to take your readings ?????

Dude:flame Dev

from the union bolt on the oil filter housing.

6-7bar sounds healthy enough. just a thought did you have your block re-bored when you had a rebuild caus if you did they may over bored the block and that would cause excessive crank case pressure. dunno much about the breather on a supra but if it aint 100% it could easyly blow a seal.

I had brand new toyota short block. Thats why im a bit puzzled by this problem.

Ive had a look on the SF and it seems that 6-7bar is right at WOT but my max reading on my defi's is over 7 but not past 7.5 (Cant remember the exact reading without looking again)

So i got to thinking, Should i change to a thiner grade of oil to lower the pressure slightly? Is this how it works or am i being a dumbass?

Im currently on Magnatec 10/40

Should i go to Magnatec 5/30 ?????

My only concern with going to the 5/30 is that i already get a bit of oil through my turbos with the 10/40, so how much difference will the 5/30 make.

Will there be a lot more blowby or will it not be noticable?

Scott

The crank front seal does not, or at least should not see any oil pressure at all. It *MAY* be seeing crankcase fumes building up a pressure, either due to piston / ring blow by, the cause of the US failures, IMO, due to them running silly boost and getting det, causing ring or piston troubles. The seal should only deal with oil splash. The stock seal, used out of the packet should be fine even on a so called 1000 BHP engine. The only way a seal will leak on a healthy engine is crank nose grooving due to wear, usually caused by previous running with cheap oil, or lack of oil changes, or by blow by. All IMO.

If the crank nose is grooved by wear taking a new stock seal, carefully removing the tension spring, finding the joint, unscrewing it, cutting about 10 mm from it, re-assembling and carefully refitting a now tighter seal over the crank nose, may fix things. It's still a crutch for a worn crank though. There are proper repair processes for worn oil seal journals though, from plasma spraying and grinding and polishing, to slip on sleeves, Loctited in place, and using a bigger ID seal. Then there are the bizarre cases. I can grind and polish a crank, have it micrometer up PERFECT for size on the rear oil seal journal, and GUARANTEE it will leak oil like a sieve. I save that trick for bad debters though

Surely my rings should be practically perfect and not allow any kind of fumes/excessive boost to be passing by them?

Seeing as my whole bottom end is brand new with about only 3-4000k on it?

Im only boosting 1.1 bar so its not like im really pushing a shed load of pressure through the engine.

Now i am baffled as to why the seal has blown out.

Scott

Pull all the closed circuit breather stuff off, block the PCV valve and run it under full boost on a rolling road, see if it's venting excessively.

Im going to have to finish off putting the new seal in tonight and see how it goes. The car is going to Thor soon so your suggestion could be done there.

Chris, Would removing my EGR be causing any excess crankcase pressure?

Scott

Originally posted by veilsideTT

Im going to have to finish off putting the new seal in tonight and see how it goes. The car is going to Thor soon so your suggestion could be done there.

 

Chris, Would removing my EGR be causing any excess crankcase pressure?

 

Scott

Not as far as I can see, no.