TT Paul Posted December 1, 2014 Share Posted December 1, 2014 just had the single fitted low boost,oil pressure is good, now i have a oil leak from crank seal i know its not above it had a good clean and look. the seal is only a few months old, on idle takes about 10 mins to start leaking a little. but a 1 mile drive on wot puts out alot more, its going into garage on thurs for new seal worth doing pump to? your thoughts Quote Link to comment Share on other sites More sharing options...
listy Posted December 1, 2014 Share Posted December 1, 2014 It may just be that the seal is incorrectly fitted. If it is anything but flush, it will seep oil. Often people don't fit them in far enough, or too far (easily done) and it only has to be half a mm, and it will leak. I'd just go with a replacement seal for now, and keep an eye on it. Possibly save yourself circa £200. Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 1, 2014 Author Share Posted December 1, 2014 May be an idea what i wad gonna try see how it goes Quote Link to comment Share on other sites More sharing options...
Littler Posted December 1, 2014 Share Posted December 1, 2014 It may just be that the seal is incorrectly fitted. If it is anything but flush, it will seep oil. Often people don't fit them in far enough, or too far (easily done) and it only has to be half a mm, and it will leak. I'd just go with a replacement seal for now, and keep an eye on it. Possibly save yourself circa £200. This is more likely the cause, fitted to far in or not enough. I'd consider getting one of Chris Wilson's modified seals with the extended lip if your going to replace it (if he has any left!) Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 1, 2014 Author Share Posted December 1, 2014 I have got one of his seals so hope that does it Quote Link to comment Share on other sites More sharing options...
Geo Posted December 1, 2014 Share Posted December 1, 2014 seen a few posts now with this. Now question, have you had cams fitted when going single? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 1, 2014 Share Posted December 1, 2014 If the seal is fitted correctly, and its one of CW uprated and its still leaking then its 99% certain to be the oil pump is worn and allowing too much oil to build up behind the seal forcing it to over pressure and leak. Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 1, 2014 Author Share Posted December 1, 2014 I have stage 1 hks cams done about 2k miles in tt and 300 miles with single on stock setup geo. why did you ask that chap? and not fitted CW seal yet thats next ricky Quote Link to comment Share on other sites More sharing options...
Geo Posted December 1, 2014 Share Posted December 1, 2014 i've seen instances were the cams don't seal properly at the front, and it leaks down, so not sealed properly, then people think its the crank seal or oil pump. where actually its the cams at fault. Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 1, 2014 Author Share Posted December 1, 2014 (edited) See where your going geo but its clean in that area had brake cleaner on it before i was checking area Edited December 1, 2014 by TT Paul (see edit history) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 1, 2014 Share Posted December 1, 2014 If the seal is not very old and in not pushed in enough to obscure the oil pump drain hole, then it will almost certainly be the oil pump, have a read here for more info, http://www.mkivsupra.net/vbb/showthread.php?108524-Oil-pump-(crankshaft-front)-oil-seal-failures&highlight=front+main+seal Quote Link to comment Share on other sites More sharing options...
Chris Bailey Posted December 1, 2014 Share Posted December 1, 2014 If the crank seal has been pushed in too far it can cause a leak, should sit flush. Quote Link to comment Share on other sites More sharing options...
np89 Posted December 2, 2014 Share Posted December 2, 2014 Its to do with the crankcase pressure on a big single. The stock breathing system is inadequate to deal with that pressure. You need to modify the stock breathers with -AN fittings and hoses into a catch can to breath the crankcase sufficiently. Its blowing the seal out Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 2, 2014 Author Share Posted December 2, 2014 Got it open at the min with a filter on for now but i.ll do that shortly fit a catch can Quote Link to comment Share on other sites More sharing options...
np89 Posted December 2, 2014 Share Posted December 2, 2014 Afaik you have to remove the factor breathers and weld in the AN fittings and do the hoses etc. That was a very useful piece if advice given to me by Mark Luney of SATS Cosworth in regards to my own car when i fitted the BL S366HF. Those guys really know their stuff! Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 2, 2014 Share Posted December 2, 2014 Its to do with the crankcase pressure on a big single. The stock breathing system is inadequate to deal with that pressure. You need to modify the stock breathers with -AN fittings and hoses into a catch can to breath the crankcase sufficiently. Its blowing the seal out Afaik you have to remove the factor breathers and weld in the AN fittings and do the hoses etc. That was a very useful piece if advice given to me by Mark Luney of SATS Cosworth in regards to my own car when i fitted the BL S366HF. Those guys really know their stuff! Totally disagree, the US guys seem to go with this theory, but having disproved it myself its not down to crankcase pressure. Quote Link to comment Share on other sites More sharing options...
np89 Posted December 2, 2014 Share Posted December 2, 2014 Totally disagree, the US guys seem to go with this theory, but having disproved it myself its not down to crankcase pressure. Ok, fair enough and you are entitled to your opinion, I was just stating what I was told by a team that is running a 1000bhp+ drift car and build engines for people up and down the country. Be interested in how you have disproved this theory though? Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 2, 2014 Author Share Posted December 2, 2014 Its a fair comment np you made and ricks previous ideas Just gonna get the seal done 1st go from there. And ordered a catch tank Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 2, 2014 Share Posted December 2, 2014 Ok, fair enough and you are entitled to your opinion, I was just stating what I was told by a team that is running a 1000bhp+ drift car and build engines for people up and down the country. Be interested in how you have disproved this theory though? Without going into a complete monologue on the subject, I did loads of reading and discussion on the US forums, and after I suffered FMS failure twice, and found that my oil pump was worn and allowing escaping oil to pressurise the seal, even though I had a modded pump with the drain hole enlarged, I started to investigate further, I then ran several experiment's using accurate vacuum/pressure gauge attached to the crankcase, with std breathers in place, catch can both recirc and open, this was done at several different boost pressures and loads, and the result was that at no time did I get positive crankcase pressure. The was with a GT4088 turbo. Now I dare say that there could be a a slight build up of crankcase pressure on a highly tuned 1000bhp + running high boost pressures, however I have yet to see any proof that this is the case, given that most high output engines have modified breather systems and as boost increases so does ring seal. also the internal pressure would need to be very high to force the seal out, however if the force is hydraulic as in pressurised oil it is capable of exerting a much grater force. Quote Link to comment Share on other sites More sharing options...
bignum Posted December 2, 2014 Share Posted December 2, 2014 I`m running stock breather system @around 600bhp for 6 years with no issues. Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 4, 2014 Author Share Posted December 4, 2014 (edited) well after a few hours work oil leak sorted, appears the spring had some how come off and was not fitted correctly, thanks to my mechanic and good friend, anyone else in hants area with a supra and needs work doing i would go to him all done in a day and good price too:d https://www.facebook.com/pages/Pages-autos/292376094256351?fref=ts Edited December 4, 2014 by TT Paul (see edit history) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted December 4, 2014 Share Posted December 4, 2014 Waits for the "its happened again" post, sorry fella I really hope its doesn't happen, but like I said I've been there and got all the badges. Quote Link to comment Share on other sites More sharing options...
Scooter Posted December 4, 2014 Share Posted December 4, 2014 Do you know if a brand new pump has any leak off into the drain hole/area behind the seal? Is it that it shouldn't? It shouldn't unless a certain pressure is reached? Or it should but only a tiny bit that runs harmlessly down the drain hole? Quote Link to comment Share on other sites More sharing options...
TT Paul Posted December 4, 2014 Author Share Posted December 4, 2014 I know again but at least its done. funny how it took a few months to leak Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 4, 2014 Share Posted December 4, 2014 All rotary pumps leak some oil from the rotors as they need clearance to run at all. this oil that is not fed to the oiling system drains through a very small hole in FRONT of the pump, and BEHIND the front seal. A pump in good order leaks not much oil at all and the drain hole copes just fine. A worn pump can leak a lot of oil and if the drain hole is overwhelmed pressure builds. The pump can build enough pressure to cause the seal to leak or even be ejected against the back of the timing star wheel. having dealt with more of these things than i care to recall i can say with certainty they leak either due to worn oil pumps, or due to the nose of the crank having a wear ridge worn into it by the seal lips. My high tension seal will often help with a wear ridge if it's not too extreme. A worn pump needs replacing and in my opinion it's an engine out job to do satisfactorily due to oil dripping down and general lack of access. The RB series of engines in Skylines has a FAR, FAR bigger drain passage, and never suffers this issue. The (hugely expensive) Tomei race pumps for the RB's have three large drain holes! As Tricky-Ricky so rightly says, an engine in good order will never pressurise the crankcase enough to cause seal issues. I too have measured crankcase pressure on both good and leaking engines and seen no issues. A "1000 BHP" engine if it really makes anything like that power, will flex the block and bores so much anything could happen. I do not attempt 1000 BHP 2JZ-GTE engines as I know such boost will just give grief. Quote Link to comment Share on other sites More sharing options...
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