Why 6000 miles?

[s2art]

Any experts out there? 6k miles seems a fairly short service interval for a shimmed engine these days. Old 911's would easily go for 12K (and actually a lot longer before reshimming required). Some modern bikes seem to go for tens of thousands of miles before reshimming. Whats going on? Is the shim material relevant?

[plotloss]

How do you mean re-shimming?

They need a tappet adjustment at 12K but I have never heard of this re-shimming business.

Can you explain?

Matt.

[jeremyc]

I think I am correct in saying all recent TVRs (Chimaera/Griffith/Cerbera/Tuscan/Tamora/T350C) have 6000 mile service intervals - its not just the Speed Six engine models.

This is normal for engines in such a high state of tune and high specific output - as Matt says its not necessarily to adjust the tappets every time.

If its a worry you're probably better off with a Porker...

[s2art]

Maybe I got the wrong end of the stick. If its simply a tappet adjustment why so long (service time)?
I have had old 911's which did require the shims measured to reset clearances, not the same thing at all then.
Still seems pretty short 6K.

[RichB]

s2art said: Still seems pretty short 6K.

Seems ok to me. Rich...

[beano500]

IIRC Mitzi 3000 GTs need services at 4.5k and most bikes (sports) I can think of need them at about 3k. I think 6 is about reasonable.

Further, in my experience, I know that my Griff always looks forward to a service between 5-6k - you can "feel" it coming on!

[andyvdg]

Not sure I understand what you mean by shimming.

The oil is changed every 6000 miles - and the car given a good going over for safety reasons. Usually involves a serious tune up (new plugs as well). If you're lucky it'll get cleaned as well.

At 12000 miles in addition to the 6000 mile service the tappets are adjusted using "shims", diff / gearbox oil changed. Service takes a little longer.

You could argue that all cars should have their oil changed every 6000 miles.

Does this help ?

[s2art]

Shimming (maybe not correct term), to use variable thickness (i.e thinner) shims to modify valve clearances. Rather than some tappet adjuster.

>> Edited by s2art on Friday 21st March 17:19

[s2art]

Changing oil at 6000 certainly a good idea with mineral/semi-synthetics. Debateable if really necessary with modern synthetics (I think Mobil 1 advert claimes up to 20,000, not that I would leave it in that long in any car let alone a high performance one)

[alans]

If the normal oil usuage is 1 Ltr per thousand miles, at 6K miles you have already replaced 6 ltrs!
So is there any oil in your engine that needs replacing at the 6k service?
Alan

[kevinday]

alans said: If the normal oil usuage is 1 Ltr per thousand miles, at 6K miles you have already replaced 6 ltrs!
So is there any oil in your engine that needs replacing at the 6k service?
Alan

Yes, there will still be some of the original left, calculate it as follows:

at 1K miles 6 - 1 = 5
at 2K miles 5 - 5/6ths = 4&1/6th
at 3K miles 4&1/6th - 4&1/6th 6ths etc.

Also don't forget any 'foreign bodies' in the oil need to be removed by draining the oil and changing the filter.