Twin Cam - Cam Cover

[J J DIKKE]

Hello All
I have recently purchased a cam cover, I am preparing this to be fitted to an engine shortly. The cam cover has previously had its 8 stud holes drilled out way too large (reason unknown). Does anyone have suggestions as to the best way to now seal around the studs, when fitted to the head ?

I do not wish to have this alloy welded and re drilled. I intend to use Viton rubber washers and nyloc nuts, obviously at the correct torque, rather than the usual seloc washers.

Thank you for any suggestions as to a solution to seal around the studs.

[lotusfan]

You could try epoxy glueing some short lengths of aluminium tube into the holes. Outside diameter to match the hole and inside diameter to match the stud. Easier than welding and drilling - maybe difficult to find correct tube size but could be made on a lathe.

[SimonH]

How big is too big? You could get them drilled to a size and get some ally bar, drilled correct size, sliced and glued in somehow. As long as your washers are big enough to reach the proper cover metal it should hold and be oil tight

[2cams70]

Do yourself a favour. Get it properly welded. You won't be able to tell it's been repaired if you have a good job done. Someone cut a big hole in mine for a breather tube and I had it welded up and the repair is now invisible from the outside. When it comes to torqueing up the cam cover bolts don't use the figures quoted in manuals. It's too much and you'll squeeze out the gasket or distort and possibly crack your cover. Just tighten it evenly enough to partially compress the gasket and leave it at that. They are just cam cover bolts not important ones like the big end bolts inside your engine.

[bitsobrits]

Top hat flange bushings, usually available in brass or bronze could be handy if you are going the non welding route.

https://www.rainbowprecisionproducts.co ... oilite.jpg

[oldchieft]

it might not work, but I would try with top-hat rubber bushes.

https://www.grommets.co.uk/products/bus ... ed-bushes/

Jon the Chief

[elanner]

The earlier question of "how big?" still stands.

A long time ago somebody enlarged four of the holes in my cam cover because the head was fitted with non-stepped cam bearing cap studs. I guess stepped studs were hard to obtain at the time (the car was in Canada).

I subsequently fitted correct, stepped cam bearing studs. I find that standard Seloc washers still seal fine, despite the cam cover holes being slightly oversized.

Nick

[J J DIKKE]

Hello all,
Thank you for the contributions on this subject thus far. The suggestions that various contributors have made are extremely helpful and I intend to try some or all of them. The thought of a aluminium, brass or high performance rubber top hat or flanged type bush sounds really good and would probably achieve my objectives.

As I noted in my original posting I do not wish to have this cam cover welded and therefore my question was based on finding an alternative solution. I have quite a number of cam covers, therefore this particular cover can be treated as an experiment, but come what may I will get this right.

In relation to the size of the holes as they are now I have this as an update. Whilst I have no professional measuring equipment, I am not a professional engineer, a number of these holes are circa 10mm across.
I have also had a powerful magnifying glass on these and if I am correct someone may have filed these to the size and shape that they are as a number of them are an extremely irregular shape.

If I am to drill these out to make them "straight" and then find a flanged bush as mentioned earlier, with an ID size as per the cam cover studs, perhaps a similar shape to an aluminium rivet nut, I could then bond this in as one contributor suggested. I do have loctite high performance 2 pack epoxy, suitable for use with oil and heat.

My thanks again for any further information and or ideas,

[promotor]

Hello all,
Thank you for the contributions on this subject thus far. The suggestions that various contributors have made are extremely helpful and I intend to try some or all of them. The thought of a aluminium, brass or high performance rubber top hat or flanged type bush sounds really good and would probably achieve my objectives.

As I noted in my original posting I do not wish to have this cam cover welded and therefore my question was based on finding an alternative solution. I have quite a number of cam covers, therefore this particular cover can be treated as an experiment, but come what may I will get this right.

In relation to the size of the holes as they are now I have this as an update. Whilst I have no professional measuring equipment, I am not a professional engineer, a number of these holes are circa 10mm across.
I have also had a powerful magnifying glass on these and if I am correct someone may have filed these to the size and shape that they are as a number of them are an extremely irregular shape.

If I am to drill these out to make them "straight" and then find a flanged bush as mentioned earlier, with an ID size as per the cam cover studs, perhaps a similar shape to an aluminium rivet nut, I could then bond this in as one contributor suggested. I do have loctite high performance 2 pack epoxy, suitable for use with oil and heat.

My thanks again for any further information and or ideas,

A flanged bush is the best approach - be aware that if the top is too high though you might not have enough thread engagement on the 8x cam nuts. There's little room as it is when using Seloc washers and slimline Nyloc nuts on a standard cam cover.

It would be good to see the result once you've done it. Best of luck.

[lotusfan]

If I am to drill these out to make them "straight" and then find a flanged bush as mentioned earlier, with an ID size as per the cam cover studs, perhaps a similar shape to an aluminium rivet nut, I could then bond this in as one contributor suggested.

One thing to bear in mind if the holes have been filed larger rather than drilled larger you may find that the original hole centre has moved slightly. Thus if you fit a flanged bush you may find that the holes don't quite line up with the studs. Easily fixed by drilling out the new stud holes 1 or 2 mm larger.

Keep us informed how you progress.

[2cams70]

May I ask why you don't want the cover welded?? It's by far the best engineering solution. If the diameter of the oversize holes are still within the original boss cast into the cover for these holes welding or aluminium brazing the holes up and re-drilling is simple. Very simple and better than stuffing around with epoxy and flanged bushes. Perhaps if you could post a picture a better assessment could be made.

[J J DIKKE]

Thank you promotor. Yes I think my starting point here will be a brass, bronze or aluminium flanged bush. I had thought about this being too tall and therefore not permitting enough thread left on the stud, however, I did consider countersinking the top face of the cover in order that the bush would sit down into the cover.

My next task is to ensure the filed holes are central on the studs and then to drill them straight to permit the bush to fit the cover properly. I also now need to identify a supplier that can provide a suitable sized bush.

Thank you once again.

[J J DIKKE]

Hello Lotusfan
Thank you for your reply. The information you give is exactly as applies to this cam cover and I had considered that. I placed this cam cover onto a cylinder head some time ago and the filed holes are exactly as you suggested they may be and not at all central in relation to the studs.

I need to now make them central prior to drilling them out with straight sides which should permit me to choose a correct size of bush. I am also now looking to identify a suitable supplier for the bushes, when I have an accurate idea of size.

Thanks once again

[2cams70]

Apologies if I’ve offended you in some way with my line of questioning. Appears I have!

[J J DIKKE]

Good afternoon 2cams70
Thank you for your latest response.

First and foremost allow me to absolutely assure you that you have not offended me in any way, your reply postings have quite simply puzzled me to some degree.

The core of my initial posting centred on my wish not to weld this particular cam cover (one of the many I own). I was somewhat surprised therefore to receive a suggestion which indicated that I should do myself a favour and have it welded properly. My preference to not have this cam cover welded has now changed slightly into an absolute determination not to have this cam cover welded.

I have a myriad of reasons for progressing in this direction with this particular cam cover, those reasons I may choose to expound upon in due course given time. On reflection I suppose my primary reason would be to spend more enjoyable and productive time in my small workshop in an attempt to steer myself away from the circa 500 bottles of Argentinas finest, currently residing in our wine racks.

Finally for now, I repeat you have not offended me, after all as I continue to say I am simply an amateur engineer seeking to learn, however, I intend to complete this job without any involvement of a tig welder and trust me I will get this right (I am obviously fully aware that re-welding and re-drilling is by far the best engineering solution).

Thank you once again.