37 replies to this topic

[nicklouse]

 

Could you get some wire brush action in there and see after a run round the block?

I´ll try to get to it this evening or tomorrow, maybe i´ll find some hints 

 

Just get some UV dye. It will help you see just how much or little work need doing rather than just doing everything.

[humph]

 

 

Could you get some wire brush action in there and see after a run round the block?

I´ll try to get to it this evening or tomorrow, maybe i´ll find some hints 

 

Just get some UV dye. It will help you see just how much or little work need doing rather than just doing everything.

 

 

This, UV trace fluid is the answer. So my freshly rebuilt 998 had a leak at the fan side. Was trickling from the cylinder head gasket at the back of cylinder 1 (fan end). There's an oil way here and there seems to be a common head gasket failure point on the A-series.  Was running down the block where the fan pulleys are and looking as though it was coming from various places.  Was only leaking when the car was hot and oil pressure up.

[emile]

I finally got a hold of UV dye. It looks like the Oil is coming from the back of the Engine (fan side), but it´s coming out under the exhaust manifold. There is a cylindrical part attached to the block under the exhaust manifold and it´s looking like it´s all coming out from there. 

I tried getting a photo of it, but it´s a pretty difficult location to get a photo of.

I don´t know if it helps, but it´s a photo straight up from under the car, on the bottom of the photo there´s the left hand stub axle. You can also see the fuel pump further up on the right.

Does anybody know what the problem could be or how to get a proper seal on that cylindrical part which is attached to the back side of the block? (To be honest, i have no idea what that part is.)

[emile]

Maybe now

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•  IMG_6738.jpg   15.71K   14 downloads

[emile]

That's the cylindrical part I meant. It has a curved tube at the bottom with a square flange that goes to the block.

 

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•  IMG_6748.jpeg   72.42K   4 downloads

[Bobbins]

That’s a tappet chest cover. There’s two, one nearest the fan has a “breather” fitted which is the small cylinder you’re looking at. Behind the cover there’s a gasket which will need to be replaced.

The gaskets are available from Minispares etc, the one you need is the orange rubber type not the earlier cork version. I’ve found them to be a very poor fit and the sizes supplied vary quite a lot, it can help if the new gasket is sealed to the cover with some Loctite before trying to refit the cover to the block.

Hope this helps, it’s a fiddly job with everything in situ though!

[emile]

That’s a tappet chest cover. There’s two, one nearest the fan has a “breather” fitted which is the small cylinder you’re looking at. Behind the cover there’s a gasket which will need to be replaced.

The gaskets are available from Minispares etc, the one you need is the orange rubber type not the earlier cork version. I’ve found them to be a very poor fit and the sizes supplied vary quite a lot, it can help if the new gasket is sealed to the cover with some Loctite before trying to refit the cover to the block.

Hope this helps, it’s a fiddly job with everything in situ though!

 

Thanks a lot Bobbins! I´ll probably get to it on the week-end.

Will keep you updated :)

[sonscar]

It is only secured by one bolt,but what fun to replace it.Steve..

[humph]

If it's the tappet chest gasket as you think then make sure you get the little rubber grommet that seals the bolt hole as this will likely be in bits. 12A1176, item 18 below.

 

https://www.minispar...ver.aspx?1~2~25

 

I'll also refer back to my post 17.  The leak I refer to that was tracked to the cylinder head gasket behind the cylindrical breather you mention and was dripping down the front and back of the engine, and was difficult to see even with UV trace. 

 

Start by changing the tappet cover gasket as it's "easier". Oh boy is it fiddly if you've got big hands. Make sure you check the torque value for tightening as it's very low (3-4 lbft ??) so it's easy to bend the cover and then it will leak.

Edited by humph, 13 December 2023 - 09:32 AM.

[Bobbins]

I posted these photos some time ago because the quality of some of the gaskets is pretty crap, great gaskets but not the correct dimensions which will make them prone to leaking. I’ve had multiple gaskets from the same source and the dimensions have varied so it’s very much hit and miss, ideally you need a gasket that fits the cover without needing stretching:

[gazza82]

I think I've read there are two types of tappet chest covers.

One is for the rubber seal and the other the cork. I don't think the seals are interchangable so don't fit the other cover.

[emile]

If it's the tappet chest gasket as you think then make sure you get the little rubber grommet that seals the bolt hole as this will likely be in bits. 12A1176, item 18 below.

 

https://www.minispar...ver.aspx?1~2~25

 

I'll also refer back to my post 17.  The leak I refer to that was tracked to the cylinder head gasket behind the cylindrical breather you mention and was dripping down the front and back of the engine, and was difficult to see even with UV trace. 

 

Start by changing the tappet cover gasket as it's "easier". Oh boy is it fiddly if you've got big hands. Make sure you check the torque value for tightening as it's very low (3-4 lbft ??) so it's easy to bend the cover and then it will leak.

Yesterday while demounting the tappet chest cover (It is indeed quite fiddly to wrap your hands around the exhaust manifold...), i already wondered how the screw would be able to seal the cover completely, i just ordered the little rubber grommet as mine is pretty much non-existent.

 

I still have your point with the cylinder head gasket in mind, but i´ll change the tappet chest cover seal first and hope that it´ll solve the problem. I don´treally want to take apart the block to change the cylinder head gasket...

 

Thanks for the advice about the torque, i probably would´ve overtightened it.

[emile]

I posted these photos some time ago because the quality of some of the gaskets is pretty crap, great gaskets but not the correct dimensions which will make them prone to leaking. I’ve had multiple gaskets from the same source and the dimensions have varied so it’s very much hit and miss, ideally you need a gasket that fits the cover without needing stretching:

 

When i started trying to un-leak the engine, i ordered a couple of seal & gasket kits just to be sure to have everything i need. I have 4 tappet chest cover seals from 2 different manufacturers, but they´re all a little too small and need some stretching to fit.

 

Is that a big problem? Should i buy more seals until i get one that fits? I would´ve used some Hylomar or Loctite flange sealant just to be sure that it seals properly..

I live in Germany, so there aren´t a lot of mini part dealers around, but ordering parts from the UK takes a lot of time, especially now before christmas.

Edited by emile, 14 December 2023 - 12:36 PM.

[Designer]

Make sure you have the washer cup part no 12A1177 that goes over the rubber bush 12A1176, if you don't have it you will never get a proper seal as the bolt will distort the bush when torquing it up.

[emile]

Make sure you have the washer cup part no 12A1177 that goes over the rubber bush 12A1176, if you don't have it you will never get a proper seal as the bolt will distort the bush when torquing it up.

There are no german dealers that have the washer cup in stock. I just tried to build one myself with the exact dimensions, it just looks a bit different... Do you think this will work?

Attached Files

•  ecc41e61-ab0a-45f4-8d6e-47ac4ad2055f.jpg   28.94K   4 downloads
•  61c35dc2-567f-40d6-b564-ec16b2f7a4d0.jpg   23.4K   5 downloads

Edited by emile, 14 December 2023 - 02:04 PM.