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| Moderated by: Greg Fletcher |
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| Good oil seal - bad oil seal | Rating: 
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| Posted: 05-09-2010 09:05 pm |
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1st Post |
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subwoofer Member
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Ms. Jensen has a major oil leak, most probably the rear crank seal. Not many other possibilities for losing 1 litre of oil in 90 minutes engine time, with no trace of burning oil. I found the oil seals I was supplied from England (probably Lotus stock) to be difficult to install compared to other seals I have installed, I very nearly destroyed one on the exhaust cam, and the rear crank seal was incredibly difficult to install compared to the same-ish size seal on VW engines. Is this just coincidence?  Victor Reinz (VW) seal on the left, NTK (Lotus) seal on the right The outside of the two differ significantly, and I think the NTK seals are a slightly larger outer diameter than the Victor Reinz seals, since the former are easy to tear, and the latter slide in quite easily. Does anyone have a list of seal sizes on the 907? I can source seals locally from an industrial supplier at a much lower cost than any car parts store if I only know what to get... Or is it possible to mount the oil seal holder enough off centre to allow it to leak? I have to remove it from the engine to get the seal in. I would love to hear other folks experiences! -- Joachim Edit: left and right confusion Last edited on 05-10-2010 07:19 am by subwoofer |
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| Posted: 05-12-2010 02:03 am |
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2nd Post |
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Arvin Appelman Member
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If the seal is pressed fully into the housing it will leak like a crazy. It needs to be held back about 0.100". I made a spacer that will just fit the the ID of the housing and used a block and arbor press to push the seal to the spacer.
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| Posted: 05-12-2010 06:38 am |
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3rd Post |
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subwoofer Member
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I think the weather (it was cold in the garage at the time - likely 35-40ºF) and the oil seal material teamed up against me. I usually install oil seals with a rubber mallet, gently tapping them in. In this case the material was so hard that I had to remove the end seal plate to install it, and after almost destroying one of the cam seals I installed it from the reverse side. As you say, this could be the reason. Having difficulties driving the seal in, I stopped when the outer surface sat .040" or so below the face of the holder. Not all the way in, but obviously too far in. I have a day off work tomorrow, will see if I can get the 'box out then. Already ordered a new seal from Greg, I'll need it for the other engine if this one can be salvaged so no loss anyway. -- Joachim
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| Posted: 05-12-2010 07:11 pm |
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4th Post |
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Greg Fletcher Administrator 
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The seals that are available these days for the 907 are not very precise. I also ruined a rear main seal on the last engine that I installed one on. In years past, you could tap it in the rear main with a drift, but the newer seals seem to prefer a press. I also noticed that the more recent front crank oil seal lip was barely touching the crank surface on my car. It seems to work, but the dimensions are not what they should be. But hey, we own a Jensen because we like a challenge, right?
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| Posted: 05-12-2010 10:19 pm |
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5th Post |
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subwoofer Member
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Right on! A challenge it is! Sounds a bit strange that only ill fitting seals are available since the engine was in production till 2000, but I guess it's simply the curse of English cars... -- Joachim
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| Posted: 10-21-2013 11:08 pm |
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6th Post |
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atgparker Member 
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So having just replaced the cam shaft seals on 11602, I drove Ortega Hwy. last Saturday to Murrieta, Ca and back. Nice hot afternoon jaunt. It got the temp gauge to almost half way with a 160°F thermo in the water pump housing. But the exhaust CAM seal is flinging oil just as it did before I replaced it. There was a large O-ring behind the intake CAM seal which I did not replace as I suspected it was blocking the oil return galleries which are mostly at the bottom of the seal on the intake but not so on the exaust cam. So, where can we get double lipped viton seals like the picture in subwoofer's post?
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| Posted: 10-22-2013 01:31 am |
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7th Post |
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Jim Ketcham Member
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You should also confirm that the cam is not leaking oil through the bolt that holds the cam gear. I have found that the set screw that seals the cam oil gallery is often missing. As this is not a tapered thread it should be installed with sealer. A leak here often looks like a seal leak.
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| Posted: 10-23-2013 12:19 am |
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8th Post |
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atgparker Member
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Jim, thanks for the prompt on the set screw inside the cam shaft. In researching the cam seal issue in the engine section of the forum I'm now aware of this plug inside the shaft. I had now idea the oil gallery is inside and axial with the CAM shafts center as I haven't had the CAMs out but it makes perfect sense for oiling the bearings in the towers. Otherwise the two holes that are just inboard of the seal's inner edge when intalled flush with the outside edge would be not return galleries and the seal would have oil pressure on them which would not work very well at all. I just hope I have a long enough socket allen and that it is the right fit in the plug. Before I replaced the cam pulleys I had "Right Stuffed" the washers and heads of the screws but the shaft is wet again like I hadn't repalced the seal at all. So the oil pressure would flow inside the slip fit between the pully and CAM shaft if the oil pressure is on this joint its going to spew and wet the shaft as it seeps out with 80psi behind it when at revs and warmed up. This make perfect sense to me now. So, I will remove the pully screws and washers tonight and see what I can find out about the plugs! When I took this apart the first time there was lot of oil behind the M10 Hex head screw/s that fix the pully so thanks again for the direction and understanding about the plugs. Cheerio, AP
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| Posted: 10-23-2013 04:17 am |
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9th Post |
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atgparker Member
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Right got it all done. The exhaust screw had very oily threads and managed to flood out all over the washer as I removed it. I bet the oil was making its way out along the key way slot and to the back edge of the pulley/cam landing surface. The set screws are M10 x 1.50 thread and take a an M5 Allen wrench which you can stuff into the deep hole length wise and apply a box end spanner to the short side of the Allen to loosen and remove. Copious amounts of Loctite 515 were applied to the threads and in front of the set screw as it is a long way done the same thread that the fixing screw uses to secure the timing belt pulley's. So I used a fair amount of this to set the screw and washer as well. Hope this does it?
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| Posted: 02-28-2014 06:48 pm |
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10th Post |
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redracer Member
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Glad to see you found the problem; for all our engine rebuilds we wrap teflon tape around the big cam wheel bolts, since, as you discovered, oil can very easily get past the allen bolt inside
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