Friday, June 30, 2006

Off with her head!

Well not quite but at least off with the rocker box and have a look at the valve clearances - Whoops! First issue, rocker gaps all over the place, evidence of some valve seat recession and also some wear in the spring caps - Dave reckons these are some unhardened alloy caps that are renowned for this, he has tehm in stock for anyone who wants them but he doesn't personally like using them. You can see the collets receeding into the caps at varying rates.
Note also Mk1 rocker pedestal and rockers on the edge of their adjustment - probably a product of 2 litre push rods being used.

Tappet clearances were as follows
1 (Exhaust) = 5 thou
2 (Inlet) = 8 thou
3 (Inlet) = 8 thou
4 (Exhaust) = less than 2 thou probably nowt!
5 (Exhaust) = 2 thou
6 (Inlet) = 10 thou
7 (Inlet) = 8 thou
8 (Exhaust) = 5 thou
9 (Exhaust) = 5 thou
10 (Inlet) = 12 thou
11 (Inlet) = 12 thou
12 (Exhaust) = 5 thou

I set them all to "a sloppy 10 thou" as Dave says :-)

We considered whipping the head off and running it down to the machine shop for valve insets to be fitted but after a few phone calls decided against this. I have a Mk2 rocker set, some 2.5 push rods and a couple of spare heads so I'll do it all soon but just no now. The head is in fact nothing too special. Whilst we were doing this Karl Dandridge turned up, he's ex-Canley mechanic and now in business for himself at Karl built the engine for Dave "Brummy" Walker the previous owner. Karl explained that the head was built from a late GT6 head, a "little tickling with the porting stone" was all that was done - you can tell the throats of the ports have been opened up.

Anyway, I knew the head had no valve inserts when I got it, I wasn't that surprised to find valve seat recession, just could have done without it being now :-)
I'd love to try one of Dave's alloy heads on it but I don't think the finances will take it just yet :-( I think roller rockers could help and as this engine gets revved hard I may just invest in a set.

Having now reset the tappets I will monitor them and see how the recession developes - I need to sort it out before the Round Britain I think. Posted by Picasa

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