Camshaft cap - sources

Camshaft cap - sources

Author
Discussion

Chimp871

Original Poster:

701 posts

58 months

Tuesday 14th May
quotequote all
So this is the company that's been recommended to me. Very few companies offer to make a cam cap and line bore.

https://www.hthoward.co.uk/engine-machining-servic...

Still not 100% sure if it's possible until he sees the head. But he sounds knowledgeable and experienced.

I sent the pictures to him and had a long chat, talked about how much thou the lower cam bearings will be taken off and how to offset via shims, shouldn't have to fettle valve tips.

Other issue in lowering cam head bearing a few thou? Chain tensioner is the only adjustment needed, and that already has a 6mm blank in it to create chain tension. Any other considerations?

Will still try an unmatched cap as it's a few weeks before the engine comes out so just want to cross this, then easiest option, off my list.

But secretly looking forward to pulling the engine and taking her apart! Strange right?

Thom

1,672 posts

188 months

Tuesday 14th May
quotequote all
They should be able to "weld-fill" the bored out cam bores in the heads then line-bore them together with the new cam caps.

A strict dimensional control should be performed afterwards to check that the heat generated by refilling the bores did not alter some key functional dimensions. By then the camshafts will still be in their original position.

Edited by Thom on Tuesday 14th May 15:41

Chimp871

Original Poster:

701 posts

58 months

Tuesday 14th May
quotequote all
Thanks.

Any issues with lowering the camshaft Centre line a few thou? I'd rather make sure I'm not causing problems elsewhere before going down this route.

Shims
Belt tension - will tensioner be enough?
Clearance issues...

I've spoken to a lot of people now, and hope this doesn't happen to anyone else as its a difficult solution and not many people want to do it, hence the specialist.

Thom

1,672 posts

188 months

Tuesday 14th May
quotequote all
I have no experience working on an AJP so just my 2 pence worth, but tappet clearances should be set the same - have to check before the machining how much shimming is needed to make sure you will stil have room for adjustment post machining, but then if the heads are off it may be worth having new valve seats fitted to "reset" valve seat wear to zero thus maximise unshimmed tappet clearance.

As I understand the cam timing procedure in the manual it is effective regardless of the physical position of the camshafts relatively to the crankshaft, so no worries unless perhaps the heads were skimmed "too much" already in the past or other nasty surprise.

Chimp871

Original Poster:

701 posts

58 months

Tuesday 14th May
quotequote all
My shims were all between 2 to 2.50 mm so not bad. But point taken and before work is done he'll call.

He may have mentioned 3-5 thou would come off but honestly can't remember.
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Jhonno

3,459 posts

82 months

Wednesday 15th May
quotequote all
I'd be wary of reducing the gap, one of the AJP issues is the shims get too thin after many miles..

Chimp871

Original Poster:

701 posts

58 months

Wednesday 15th May
quotequote all
Agreed. I can get back the loss back either through the shims, valve tips or valve seats as Thom mentioned.

Time will tell.

Focusing on getting the old carpet out for new at the moment. Seat, bolsters, rear parcel shelf, helmet trim, door card trim all off in June for reupholstery or repair.

ukkid35

4,742 posts

114 months

Thursday 16th May
quotequote all
Chimp871 said:
Agreed. I can get back the loss back either through the shims, valve tips or valve seats as Thom mentioned.
You can't get much back from the valve tips, because of the depth of the shims, which it would be unwise to reduce


ukkid35

4,742 posts

114 months

Thursday 16th May
quotequote all
Chimp871 said:
Focusing on getting the old carpet out for new at the moment. Seat, bolsters, rear parcel shelf, helmet trim, door card trim all off in June for reupholstery or repair.
Anything you can suggest here would be much appreciated

https://www.pistonheads.com/gassing/topic.asp?h=0&...

Thom

1,672 posts

188 months

Thursday 16th May
quotequote all
Jhonno said:
I'd be wary of reducing the gap, one of the AJP issues is the shims get too thin after many miles..
What material are the shims made of?