Triple Cam Blocks

tom3c75

tom3c75

Hero member
Location
Cape Town South Africa
Question: 

Can the later cam blocks be used to replace the earlier version, i.e. the version that makes use of a centralising bush/dowel to locate the cam block in the cylinder head?

If so, do the dowels need to be retrofitted to the newer cam blocks, or can the dowels be disposed of?   
Are any other changes required?

Thanks
 
Hi Tom - The earlier heads don't have the locating slots that the newer pillars locate in. You can use the later ones and modify them to take the earlier sleeves - you may have to modify the underneath's also - Regards - Phil
 
Tom,
we do billet CNC versions that are suitable for all versions of heads if they are any help
have used them numerous times now on the early heads due to the early cam blocks collapsing

what issue are you trying to solve ?

Red

 
hi Tom the billet cam block conversion to your early head is easy May need a little relieving particularly the centre block your original dowels will pick up the new blocks.
You can forget about the top end with them in!!!
 
Red, I suspect that the cam blocks on the 3C may be giving a little, so I?m investigating replacement options.    I?ll try and measure the blocks when I next do the shims and then, hopefully, get a better idea.   

Also, there?s a possibility that I may need to replace the guides (previous machinist fitted K-liners). 
This will no doubt result in seat work, which will result in a loss of shim thickness. 
My understanding is that your billet blocks can be supplied to compensate for this loss, so perhaps this is a better option.

Maurice, thanks for the thumbs up!

Tom
 
not so simple Tom,
we made the offset cam blocks to regain shim thickness when we find heads that have been decked in a previous life, we have them in 0.0mm standard size or 0.2mm and 0.4mm offset.
but if the head has not been decked then it is not really possible to move the camshaft up as then the cam chain gets too tight
if your current shims are on the low side then when you change out the Valve Guides and recut the Valve seats which you will have to do, you may find you are in the unserviceable valve shim range

you have two choices
change the valve seats to new valve seats and start again, that is what we would do

or get shorter custom made valves

 
redax5 said:
you have two choices ...
Click to expand...

Choice 3: Take the cams and camchain out, cut some inlet and exhaust ports in the cylinders, bolt on a blower (can't use crankcase compression), and turn it into a supercharged 2-stroke. The spark plugs already fire every revolution so you won't have to touch the ignition.  :D
 
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