XPAG rear oil seal modification

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timandgerda
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XPAG rear oil seal modification

Post by timandgerda » Sat May 25, 2019 5:58 am

I am just about to fit the speedy sleeve to my xpag crank as part of the oil seal modification and some advice would be welcome. It looks like it will have to overhang towards the engine ie away from the flywheel by about 2mm unsupported on the flange - is that normal? Has anyone used sleeve lock or sealant when fitting and finally I guess I will have to remove the flange from the sleeve when installed - do you just snip in one place before installation with tinsnips or am I misunderstanding this?

Thanks

Tim

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Re: XPAG rear oil seal modification

Post by frenchblatter » Sat May 25, 2019 9:09 am

Tim, I fitted mine backwards after ruining 3 seals. I turned a piece out of the flywheel but think it wasn't required. I fitted the seal onto the sleeve after soaking the seal in boiling water then fitted the seal onto the crank with the flange outwards. There's pictures on my blog, I'll see if I can find them. Back soon.
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Re: XPAG rear oil seal modification

Post by frenchblatter » Sat May 25, 2019 9:28 am

OK, go to www.frenchblat.com and select "Daily Blog". Then click on July and read on. Beware that there are two cars with Moss seal conversions. Mine is the black car the other is green and belongs to a friend.

The problem was the instuctions no longer state that some flywheels have a very short boss. The seal kit is designed for the long boss. When fitted as instructed to the short boss the seal lip is not fully in contact with the boss, it's half on, half off.

Personally I would leave it with the scroll unless you've started the conversion.
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Steve Simmons
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Re: XPAG rear oil seal modification

Post by Steve Simmons » Mon May 27, 2019 8:14 am

I fitted mine backwards as well, and it did overhang a bit. This is necessary on some blocks for reasons no one has ever figured out. Be extremely careful with the sleeve. Just the smallest bend or imperfection and you will have a leak. I used sleeve retainer to hold it in place.
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timandgerda
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Re: XPAG rear oil seal modification

Post by timandgerda » Mon May 27, 2019 1:57 pm

Thanks for the comment Norman and Steve. The problem seems to be that the speedy sleeve is barely deep enough for the seal footprint. Did you put your seal on the sleeve first Steve and leave the shoulder in place as Norman did? If I did this it looks like the groove for removing the shoulder would be in the running position for the rear lip on the seal. Looking at my crank it seems that I could move the whole new seal housing towards the flywheel, perhaps with a machined spacer or the like, and this would give better contact area for the seal - there is plenty of room to move it by at least 1mm without any interference issues (I have machined a little off the flywheel already). I have made a tool that fits into the block rear main bearing and the new seal carrier and this allows me to perfectly centralise the assembly (after I machined the new seal housing so I could use button head screws instead of the countersunk type supplied). I will take some pictures and add them as I progress but work commitments will hold up progress for a few weeks now.

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Steve Simmons
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Re: XPAG rear oil seal modification

Post by Steve Simmons » Mon May 27, 2019 6:24 pm

You need to maintain a seal (using sealer) between the bearing cap and seal housing, so you can't move it too much. It's been a few years but I seem to recall leaving the shoulder in place and removing it afterward. I'll have to look through some old photos and see if I can find exactly how I did it.
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timandgerda
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Re: XPAG rear oil seal modification

Post by timandgerda » Tue May 28, 2019 12:06 am

Thanks Steve - any photos you have (I have already looked at those Norman has) would be useful. I understand about your bearing cap comment but it looks like I will have to remove some material to get the new housing to align with its other half and a small spacer would still mean I have to remove some material from the cap (this is without measuring but I will post my findings later).

timandgerda
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Re: XPAG rear oil seal modification

Post by timandgerda » Tue May 28, 2019 12:06 am

Thanks Steve - any photos you have (I have already looked at those Norman has) would be useful. I understand about your bearing cap comment but it looks like I will have to remove some material to get the new housing to align with its other half and a small spacer would still mean I have to remove some material from the cap (this is without measuring but I will post my findings later).

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Re: XPAG rear oil seal modification

Post by Steve Simmons » Wed May 29, 2019 7:37 pm

Sorry I couldn't find any photos of the sleeve installation, but here are two photos of the issue.

First, a photo of how far the seal was hanging off the flange...
XPAG rear seal
XPAG rear seal
seal1.jpg (196.48 KiB) Viewed 1293 times
And second everything installed with the sleeve hanging off the back. It was a VERY tight fit.
XPAG rear seal
XPAG rear seal
seal2.jpg (229.53 KiB) Viewed 1293 times
1949 TC8975 / XPAG 9609
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Re: XPAG rear oil seal modification

Post by Eric Worpe » Mon Jun 17, 2019 4:14 pm

I've noticed on some installations that the lip-seal only just engages with the flange of the crankshaft. It can be so marginal that two spacers are available of 1mm and 1.5mm thick to offset the lip-seal and increase engagement. The downside to such an approach is the need to skim the surface of the flywheel to prevent interference with the edge of the displaced lip-seal. This has to be done carefully so as not to loose the alignment guide provided by the recess in the flywheel for the crankshaft's flange.

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Duncan M
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Re: XPAG rear oil seal modification

Post by Duncan M » Mon Jun 17, 2019 8:19 pm

How long before it starts leaking? Or is this considered a permanent fix?

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stephen stierman
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Re: XPAG rear oil seal modification

Post by stephen stierman » Tue Jun 18, 2019 2:08 pm

Duncan, mine worked for a very short while, upon disassembly it appeared that with the combination of end float and the tight clearances, the seal may have been pushed too far back to make good contact with the flange. I did not use a sleeve and probably this would have helped. I went back to the original slinger, following instructions on careful fitting and can live with a drop or two upon shut down.

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Steve Simmons
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Re: XPAG rear oil seal modification

Post by Steve Simmons » Tue Jun 18, 2019 10:52 pm

The problem is that it's very difficult to know if the seal has failed or if there is a leak somewhere else. I think David Edgar's approach of tipping the engine on its back while full of oil is likely the best idea. At least then if there is a non-pressurized leak somewhere, you'll detect it before installation.
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stephen stierman
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Re: XPAG rear oil seal modification

Post by stephen stierman » Wed Jun 19, 2019 12:43 pm

Absolutely...…….
When I installed the original slinger I built a mounting stand that I could start and run the engine for awhile to detect leaks. Nothing fancy, just wooden construction and this gave me a pretty good idea where any oil might be coming from before I went to the trouble of installing the engine back in the chassis.
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engine.JPG
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Re: XPAG rear oil seal modification

Post by frenchblatter » Wed Jun 19, 2019 8:24 pm

If you look at my rebuild blog you'll see that's exactly what I did.

The problem is that some crankshafts have a much thinner flange than others. The Moss kit is designed for the wider flange. The early instructions mentioned this but the current do not. My solution was to as described in my blog. It has been running for about 2000 miles now with no leaks.
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timandgerda
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Re: XPAG rear oil seal modification

Post by timandgerda » Thu Jun 27, 2019 4:10 am

Just got the crank, flywheel etc back after balancing so hope to start the engine rebuild this weekend. My new oil seal kit instructions recommend removing material from the rear bearing cap, adjacent to the crank scroll. If I do this there would be no going back to the original system. Does anyone have any experience of fitting the new oil seal kit but not machining material off the bearing block (I don't mean machining the rear face to allow the new seal carrier to fit - I can do this without issue)? Additionally does anyone have a spare distributor for an XPAG that they would be willing to sell (I am UK based). Cheers. Tim.

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Steve Simmons
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Re: XPAG rear oil seal modification

Post by Steve Simmons » Thu Jun 27, 2019 8:32 am

It's been a while but as I recall there is a certain gap size you're trying to achieve between rear cap face and seal retainer. You then fill this with sealer. Too wide and the sealer may not work. So I'd say measure the gap and only machine if necessary.
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