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MG MGB Technical - Speedi-Sleeve?
|Took the B GT out for a club event yesterday and noted what I would call a moderate amout of oil coming out of the split pin hole when I stopped at a parking lot. The motor is at about 1500 miles since a full rebuild.|
I did not put in a speedi-sleeve and am now thinking I may need to.
I have never used one of these. Where an how are they installed for a rear crank leak?
|Was the crank journal badly grooved when you re-assembled it?|
|I used one on the pinion shaft of a Lotus differential and it worked well. You can buy them in an almost unlimited number of sizes and they come with a tool to help you install it. You start it over the end of the shaft with the flanged end inwards, then use the tool to tap it home. Because it is so thin (A) the flange doesn't matter, and (B) the original size oil seal fits perfectly. You can watch a video here|
|The oil may well have contaminated the clutch, so be prepared to replace at least the friction plate on that.|
However oil from the split-pin hole can be from the first motion shaft oil seal as well as the crank seal, you won't know until you part engine and gearbox, although if there is oil in clutch release arm boot it probably is the gearbox.
|I've installed several sleeves. Choosing the right size is critical and the fitting is helped enormously by warming the sleeve with a hot air gun or similar, and if you have a chest freezer, putting the crank in for an hour or two.|
A speedi sleeve can be installed with out removing the crank or back plate.
Remove the old oil seal and then follow the sleeve instructions. The lip can be left in place, it doesn't interfere with anything.
One important point to do is to wrap some tape around the edge, before fitting the seal, just far enough on the seal to cover that edge, otherwise the seal will be damaged when fitting.
Also make sure your lube the seal.
|H J Adler|
You may have already done this, but you should verify that your crankcase ventilation system is working properly since excess pressure might cause a seal to leak that otherwise would not.
As Paul said, it could be the transmission. If the leak is large enough, you might see the level drop. Still an engine out job, but it would be nice to have the correct parts before starting.
|C R Huff|
|The point raised by Herb about protecting the seal lip is very important, there is a special tool for doing this (18G 1108) which is great if you can borrow one, but I remember seeing rear main seals for sale with a plastic protector sleeve included in the box, soaking the new seal in engine oil is not a bad idea, the problem with not using a protector sleeve is, you don't know if you have damaged the new seal until you start it up and see it leaking,|
|Engine had 103,000 when I did the rebuild and the journals looked very nice. Only had to do 10,000 over on the bearings. Engine was line bored.|
So to clarify, the speedie sleeve goes into the engine back plate for the crankcase seal? What would cause wear on the back plate hole that the seal goes into?
OD transmission was rebuilt about 3,000 miles ago. Re-builder is very meticulous so I think it is less likely the trans seal as I did not do a good job on the crank seal.
Good point Charlie. This is a 67, so just has the diaphragm type crankcase ventilation system. But it is worth checking.
Sounds like a nice winter project to pull the engine again.
|AFAIK the sleeve goes onto the end of the crank.|
|Dave O'Neill 2|
|Bruce, if the crankcase was pressurising you would likely also see leakage at the front cover seal. Super seal are usually used to overcome a deep groove in the journal preventing the lip seal from doing it's job. Never seen one designed to re-line an internal diameter. 9Doesn't mean they don't exist) Can't see how the hole in the back plate would be oversize, far more likely that the large lip seal is under sized.|
|The Speedi Sleeve is meant to press on over the rotating shaft, not into the fixed component. I have remembered that when I used one I put some gasket sealer inside the sleeve, because although it is a tight fit on the shaft, it is possible for oil under pressure to find its way between the shaft and the sleeve.|
|The crankcase was always ventilated in two places (by design, maybe more in practice ...) so both would have to be blocked for the crankcase to pressurise. At which point the dip-stick would probably release it, unless that is tight-fitting.|
By contrast the gearbox is only ventilated in one place, via an inaccessible breather exactly the same as on the rear axle. If this gets blocked then it will almost certainly leak oil from either front or rear seals.
You may have misunderstood Herb regarding the speedi-sleeve and the backing plate. Herb was just saying that you don't have to remove the back plate to install the sleeve. Not that the sleeve mounts to the backing plate.
The sleeve gets driven onto the tail end of the crankshaft, and the rubber/leather inside diameter of the seal then rides on the fresh surface of the sleeve.
|C R Huff|
|Thanks Guys, for clarifying how a speedi sleeve is used. I guess I assumed that it is common knowledge that a speedi sleeve fits on the shaft, not the hole.|
With the old rear seal removed there is enough clearance for a sleeve and its installation tool to go through. And yes a sealer needs to be used between the shaft and the sleeve, as per instructions.
I have seen and heard about sleeves that come with a "cover" for the edge, but haven't actuall ever had one, hence the tape, to just cover the edge. I learnt about this the hard way, by having to pull the engine a second time.
|H J Adler|
|Wow, for some reason, my head is dense on this one. Anyone have a picture or a copy of the instructions for installing this so I can have an Ah Ha moment?|
|Bruce, there are some good instructions on how to fit the Speedi Sleve on this website:|
|Ok, I got that Ah Ha moment. |
It was mentioned you can put the sleeve on without removing the back plate. So, you take out the rear seal, install the sleeve (using the install tool) with the lip of the sleeve towards the engine and then reinstall the seal.
In looking on line. I saw in one internet post that they used permatex Aviation form-a-gasket #3 sealant liquid on the sleeve when installing it. Have others done this for their sleeve? Is that just an extra measure to assure no leaks between the seal and the crank?
|That's how I've done my rear seal. Another method to use with badly grooved shafts is to use a special epoxy which presumably fills the groove an ensure a solid backing for the sleeve.|
|H J Adler|
|Bruce, I use Loctite between the sleeve and the crankshaft for good measure. RAY|
This thread was discussed between 28/10/2016 and 31/10/2016
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