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  View original topic: oil leak from behind crank pulley
jfpvw Wed May 05, 2004 6:33 pm

the engine a 1600sp. there is a considerable oil leakage originating from behind the crank pulley, and am i correct in saying that there is no seal or gasket back there? if i let it warm up for a few minutes, it starts shooting little drops of oil out with the pulley, and underneath it all, oil drops are visible. now, i dont have a big enough wrench yet to get the pulley off, but when i do get one what should i be looking for?

USMCbug Wed May 05, 2004 6:46 pm

Hmmmm..... Well you may have a sand seal back there. Some of the off road baja guys use them behind the crank pulley to prevent dirt and sand from entering the engine. Mainly an off road application. If you pull the crank pulley you should notice some distinct "cork screw" grooves on the pulley shaft. If they are burred then they will not direct the oil back into the engine. If it is smooth, then look at the case where the pulley goes in for a seal. If its leaking then replace the seal. If its grooved then make sure the pulley shaft is clean. If its grooved then there is no sand seal.

jfpvw Sun May 09, 2004 8:50 pm

ok, i got the pulley off and i do see some groves on the outside of that circle where the pulley installs. i didn't see any cork gaskets there either, and i tapped around with a screwdriver to make sure they were not cork. i definitely heard the metal clanking there. how do i stop the leaking now?

bamabug67s Mon May 10, 2004 4:18 am

I had the same thing happen to me many moons ago.Turned out that the problem started when I put one of those fancy oil filler tubes on and it was not vented,thus creating enough engine pressure to force the oil out of the crank pulley seal.I unscrewed the oil filler cap and bam,no more oil leaking from crank pulley.So I tapped a hole in the cap allowing the engine to breath.Make sure your engine is "vented".It may be a seal gone bad but try this first.---Eric

keifernet Mon May 10, 2004 9:07 am

jfpvw wrote: ok, i got the pulley off and i do see some groves on the outside of that circle where the pulley installs. i didn't see any cork gaskets there either, and i tapped around with a screwdriver to make sure they were not cork. i definitely heard the metal clanking there. how do i stop the leaking now?

if you see grooves worn into the case... that is bad... it means at some point in time the main bearings failed and the crank wobbled, thus allowing the machined in oil return grooves on the pulley to eat grooves into the case. There are not supposed to be grooves in the snout of the case!... Therefore a cas that has been damaged like this will nearly always leak oil, especially if it is even slightly overfull or like stated in the other post the crankcase ventailation is blocked or diminished.

There is a remedy... Scat ( at others) make a "no machine" sand seal adaptor ( that taps into the snout of the case) and aluminum degree wheel pulley. This is what I use when I find a ( an otherwise perfectly good case) case that has the damage to the snout.

here is the link to the CB Performance version...

http://www.cbperformance.com/catalog.asp?ProductID=296

57 Zwitter? Mon May 10, 2004 9:18 am

I had the same problem...couldnt tell where it was coming from, after changing oil cooler seals , distributor seal ring, oil pump gasket I finally changed the oil filler tube. I had replaced it with a straight one without a air hose to the aircleaner and the draft tube that goes down next to the oil pump. I put the right one on and the leaking stopped! crankcase pressure caused oil to out frfom wherever it could!

jfpvw Mon May 10, 2004 2:13 pm

thanks keifer, i would need the 7" kit, right? and that should just "bolt on" to the case?

keifernet Mon May 10, 2004 2:45 pm

Yes, that is the stock size. and the seal/ adaptor just taps into the snout of the case... it is a taperd metal ring/collar with a seal installed. A 'no machining" type of sand seal. and then the pulley just bolts to the crank same as stock. And if you diddn't already have a degree wheel, now you will, making valve adjustments and timing your engine that much easier.

Still check out the other things to make sure your crankcase is properly vented. But with the wear marks you described... I have seen lots of cases that were worn around the nose of the case and that is why they leaked.

jfpvw Mon May 10, 2004 6:07 pm

thanks again keifer, i just ordered it. now we'll see how long it takes to get way the hell over here.

autotrix Tue May 11, 2004 4:24 pm

is it possible to install a sand seal with a pulley that does have the corkscrew grooves? just for a little extra protection? I have the same problem but I do have the grooved crank pulley....... :wink:

keifernet Tue May 11, 2004 6:12 pm

No, the "grooves" are actually made to reverse spin the oil back into the case... the trouble lies when the case gets worn due to contact with the grooves

the grooves would tear up a rubber seal.

( i.e. the main bearings fail and the crank moves around to much in the case thus the pully grooves are allowed to rub against the case and wear into it)

any sand seal, rather machine in or the newer style with a tap in place adaptor that holds the seal require a smooth machined surface on the pulley to ride on the seal.

turboblue Tue May 11, 2004 7:29 pm

The is one thing that might derail that idea Keith. The case snout might be worn enough the seal holder doesn't fit tight enough. Then you have to get creative. Have seen a few like that.

keifernet Sun May 16, 2004 9:20 am

turboblue wrote: The is one thing that might derail that idea Keith. The case snout might be worn enough the seal holder doesn't fit tight enough. Then you have to get creative. Have seen a few like that.

Yeah I have seen at least one so bad that the seal holder did not fit real tight either. It was an engine that was only going to see use on a " ranch huntin buggy" so I went ahead and JB welded it in place! And it has held up fine.

( the whole engine was built before I noticed how bad the snout was, stupid of me to have picked out that particular case, I just did not inspect it as well as I should have. Everything else about the case was great! Now I learned and I look real close at the snout and have new respect for it on cas checking criteria)

Wouldn't want to make a habit of it though. :!: :wink:



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