Eccentric replacement

[No Quarter]

I'm currently assembling the 3.8. I've run into a problem that I was actually warned about in Haynes manual. I used a composite head gasket, and they are thicker than OEM. So now the top chain is not long enough. Haynes book warns about this, and mentions part# C27189 as replacement eccentric.

My question here is how much disassembly it takes to replace the eccentric? Because I have to order part/gaskets. I assume I have remove head again, so need new composite gasket, but is that enough, or does front cover and therefore oil pan also have to come off?

[abowie]

Personally this seems odd to me, although I'm the first to admit that I don't know everything about the XK engine.

Have you tried rotating the adjuster in both directions? Are you sure you have the cam sprockets correctly seated? Are you sure you have the correct length upper chain installed?

Assuming that the Haynes manual is indeed correct and what you say is true, my approach would be to either replace the head gasket with a thinner one or (heaven forbid) skim the head.

You can't replace the eccentric without removing the timing cover and C4128 Lower Timing Chain Mounting Bracket and C4819 timing mounting bracket.

If you look at the SNGB site the 3.8 eccentric C2177 is superseded to C27189 anyway...

[No Quarter]

Skimming the head might be a better idea...

[No Quarter]

Andrew, to answer more detailed. My parts guy had never heard of this either. Jag manuals neither. But Haynes has. My parts guy and I ended up with this theory: As the industry moved from flat gaskets to composite, Jag made another eccentric to cope (C27189), and from a certain year, all have it. Unfortunately mine doesn't. I had hoped that production tolerances and chain stretch would solve it for me, but I won't go with non-composite head gasket, this is a car (as opposed to most early E-Types in my country) that will see action, engine has to be bullet proof.

Why heaven forbid on skimming? Ensures head is flat and straight.

Right now I'm not sure what to do, will talk to my machine shop guys.

[abowie]

Why heaven forbid on skimming? Ensures head is flat and straight.

Only that it removes material from the head that you can't ever replace. Seems a bit extreme to solve your problem.

Have you looked at a Cometic MLS gasket? They can be pretty thin, and are race quality.

[rfs1957]

I wouldn’t do anything until I’d had a conversation with Rob Beere.

[No Quarter]

Well, for now I decided to go back to the OEM gasket, and the chains are now long enough. Who is Rob, on this Forum?

[Gfhug]

No Rob isn’t on this forum but has a company working on XK engines:
http://www.rob-beere-racing.co.uk/
A well respected man judging by comments from those who’ve had engines worked on by him.

Geoff

[rfs1957]

Look up Rob Beere Racing and speak with either Rob or Carl, best source of hands on XK engine building advice I have ever found, a mine of useful advice, pleasant and frank in their dealings, everything that Chesman are not.

They sell every single part you could imagine, and fit what they sell.

[No Quarter]

Thanks all

[mtnjag]

As mentione above Cometic has a gasket that would likely work,
They have a .027” thick MLS gasket which is a Viton coated stainless-steel core gasket. As well as other thicknesses up to 0.140”
There gaskets come in various bore sizes so you can optimize you concentric fire ring.
They say that .027” is the automotive standard on Cu head gaskets.
Note that they do not show a gasket for the Etype on their website but do make them. They make many gaskets not shown on the website.
I currently have a gasket on order with them for a Sprite in .030”
Many of their MLS gaskets are made to order and are 3-5 weeks lead time.