I was going to bolt on the timing chain cover on my 2.5L MK V today. I find that the hole for the crank shaft is quite a bit larger than the shaft. The manual shows a “oil slinger” on the inside but no seal. The picture shows a pair of shims and I’m wondering if they are supposed to keep the oil from coming out of that area. Even if oil leaking isn’t a problem but the gap is large enough to allow dirt, dust and water into the area. Am I missing something?
The spiral throws the oil back in. You are supposed to place shims around the crank pulley to ensure an even gap all round before tightening the bolts on the cover. You might find it easier to wrap a few layers of tape around the pulley spiral to centralise the cover. Then tighten the cover bolts, remove the pulley remove the tape then refit the pulley.
The scroll principle was the very early technology as the Viton type material for high speed seals was not yet invented, neither was the crankcase scavenging system - positive crankcase ventilation, PCV. These scrolls are typically on the front of the crankshaft and front of the diff pinion shaft.
Their main undesirables are:
- oil can pass if the crankcase pressurises, eg ring blow-by, or from excess oil as a result of overfilling;
- usually always weeps a bit despite everything being in top condition;
- can draw dirt in by the rotation of the scroll;
I don’t know if there is any reference that confirms the orientation of the dishing for the slinger but it should face into the engine to drive the oil back away from the front.
The crank shaft has the key way with protruding key coming through to the cover, so there’s no way to fit a seal.
I’m thinking that if I can find a new oil slinger and shines, I should use new ones. Would they be the same as on a XK 120?
I’m not understanding this. I don’t see any mention of a scroll in the 2-1/2 Liter engine, neither in the manuals nor the parts catalogues. There is an oil deflector, which appears to be a flat disc, inside the cover. The fan pulley has a boss on the back which fits into the cover. That’s why there is such a large hole in it.
No, it’s not a perfect seal like a modern car, and you will get some leakage. You just have to clean it once in awhile.
BTW the XK120 engine is totally different.
Thanks, I guess I didn’t pay any attention to it when I had the pulley off to paint my engine.
That gives me some direction. I’ll go look at my pulls to see about the scroll. I looked quickly in the pulley bag yesterday and didn’t notice any shim spacers. If they are missing, is there somewhere to get replacements?
I can’t remember what’s written but perhaps the shim spacers are just suggested for centring the cover on the pulley You do want the scroll to be beneath the mouth of the cover so perhaps they were used to ensure that. The sticky tape method of centring the cover is much easier than holding little shim strips in place.
The shims are to adjust the orientation position of the crank dog nut so that when tight, the crank handle is just past the bottom centre for the best mechanical advantage for a pull up hand crank start. My previous note about the slinger washer being dished was referring to a different car, not knowing the Jag was flat.
So I had a few minutes away from the boat project and checked out the bag with the pulley. It has the pulley with the opposite thread for running oil away from the cover. There is the oil slinger which is cupped and has a slot for the key, a thick spacer with a key way, a thin spacer with no slot and a three armed lock washer. I just need to soak these in gasoline for the evening and try and put this together tomorrow.
I thank you all for your help.
The assembly order is:
- slinger (cup inwards);
- thick keyed washer;
- plain washer(s);
- lock washer;
- starting dog nut.
Only bend over one lock tab, whichever aligns best with a flat.
If the plain washer does not land the nut ears in the right safe spot for cranking, it will need to be changed for another thickness. Not difficult to make if you have one of those stepped conical cutters. It is unlikely you’ll need to change anything if what you have is what was originally fitted.
I’m curious as to how the lock washer is locked to the shaft or pulley. Without this it does nothing.
On the 3 1/2 engines I have found the Woodruff keys can make the fitment of C.2808 Centre for Damper J.7 difficult due to their required alignment and the tight fit of the Centre for Damper on the crankshaft. It can be hard to rotate the Centre for Damper on the crank to get correct alignment with Woodruff key. Putting the Centre for Damper in the oven for an hour gives enough thermal expansion for the piece to slide onto the crankshaft before cooling clamps it down onto the crankshaft. The cooling happens in a few seconds when sliding it onto the crankshaft since it is hot metal on room-temperature metal while sliding it on. Confidence is required along with swift movement or a puller may be needed to remove and try again. You may wish to consider this technique if your assembly faces this tight quarters problem.