Twincam - Cam Cover

[J J DIKKE]

Hello All
Wondering if anyone has a foolproof method to achieve this. I have purchased a twin cam, cam cover which does not currently have the 8 mounting holes drilled. Can anyone advise how I achieve an extremely accurate template/pattern/measurement in order to ensure I drill the holes in exactly the correct places?

I wish to avoid a situation I have with one of my other cam covers where someone has drilled the holes out of centre and therefore way to big.

Would appreciate any advice and or pointers.

Thank you

[2cams70]

JJDikke. You come on this forum from time to time with some, let us say, unusual questions and situations. People then invest time to respond but you never ever come back to give an update on how things are going.

Your cam cover with the enlarged holes. You asked us about that before. People replied but we never were told how it concluded.

Your strange alloy sump that you wanted to modify to a “big wing” type. What happened with that?

[512BB]

You tell him 2 Cams

And as the cam cover is probably the one I bid on, on ebay, but lost out on, I am not replying.

Leslie

[J J DIKKE]

Hello 512BB,
Thank you for your response. I guess my un drilled cam cover is not the one you bid on, on eBay as I purchased this cam cover approximately 7 years ago. When ongoing medical situations permit I will surely be able to drill this quite accurately.

Thank you anyway.

[billwill]

Try this ?

1 take a spare set of studs and in a lathe turn the top ends down until they have a pointed end.

2. fit the studs in a TC cylinder head. Line up the pointed tops of the studs with a flat plate.

3. Place the undrilled cover over the studs and line up the edges etc where it would reach the head it it was not held off by the studs.

4. tap the top with a mallet, on each stud place, check the lineup before each tap.

5. this should have made a centre-pop type of conical dent inside at each of the places where you need to drill a hole.

You could shorten the set of studs while on the lathe so that the clearance between the cover and the head is reduced to say 1 or 2mm for the mallet tapping.

[rgh0]

Another method would be to use a cardboard template cut out to the required shape and marked with the location of of 8 securing studs in the head and to transfer those locations to the cover.

regards
Rohan

[billwill]

Rohan, I reckon it's the transferring of the positions to the cam cover that is the task difficult to get right, not the inter-stud spacing etc. It would be far too easy to get the position slightly wrong, leading to the cover hanging outside the head at one end and slipped forwards or sideways a few mm at the other end.

This would likely lead to oil leaks.

[rgh0]

Hi Bill
Yes if using Carboard to make a template to transfer the locations from the head to the cam cover you need to get it accurate so as to end up with the cam cover sitting correctly on the head. I do a lot of cardboard engineering and you just need to think through how you design the cardboard template for accurate dimensional transfer.

Incidentally I have a few spare original cam covers and they all very a few mm in their hole placement so not that accurately done from the factory either

cheers
Rohan

[Craven]

Depending on the casting of your cover you need to determine where the compromise on actual fit is best placed, I would remove the 8 long studs then offer up the cover. Make from stiff cardboard or the like a template of the cover, place on top of the studs and mark, start with a small hole and enlarge correcting any error until happy! Same with actual cover start with small holes enlarge and correct with file if necessary.

[jono]

Could you not just offer up another cover, face to face, to your undrilled cover then using a suitably snug fitting drift with a 'pip' on the end mark the inside face of your cover and then drill pilot holes through from the inside?

[Billmack]

If you are not some kind of reasonably skilled machinist why buy something like that ?? Im pretty sure there are ppl who make and sell covers in finished condition. Keep in mind your wallet is a tool too!

[J J DIKKE]

Hello Billmack
Thank you for your input. I am no kind of a machinist at all and in terms of machine tools of any type I would have no clue where to start. As to your question why buy something like that, I will answer that twofold,
1. Because I can
2. In order to make a best attempt to keep my non engineering retirement brain active

When my health is a little better (fingers crossed) I will use all the information I receive from you all and venture into the workshop and have a play. Should it not work , so be it, I will have at least tried.

Thank you once again.

[Slowtus]

Measure twice, drill once, per hole.

[elated]

Or check the marking position twice before marking then drill once with a small pilot drill then successively with increasingly larger drills!

[mark030358]

Hello Billmack
Thank you for your input. I am no kind of a machinist at all and in terms of machine tools of any type I would have no clue where to start. As to your question why buy something like that, I will answer that twofold,
1. Because I can
2. In order to make a best attempt to keep my non engineering retirement brain active

When my health is a little better (fingers crossed) I will use all the information I receive from you all and venture into the workshop and have a play. Should it not work , so be it, I will have at least tried.

Thank you once again.

Good on you for giving it a go, take my hat off to you. I do think though that if people give you the time to answer your questions you should reply re success/failure. So I have to agree with one of the posts.

But there are some on the forum who just play the game, but generally us up north are pretty good.

Best of luck