Got Esc cossy bottomend wiv std +.5 oversized pistons in it.
Had full on head work, ported etc. I have had new valves, new valve guides, new valve stem oil seals, new followers infact every component in the head is new. It also has BD14 exh. and inlet cams.
The head has been skimmed.
How do I know if I'll have adequate valve clearance?
Do I have to torque it all down to check?
I have a 3 layered head gasket from Burton's (probably Cometic).
I am ready to slap the head on but I don't want to destroy it!!!
Please advise.

 

Measure the thickness of the head, minimum they reccomend is 138.68 but thats just for compression ratio more than anything, running bigger cams really u should have valve cut outs in the pistons to make sure theres enuff clearance.

 

Thanks mate, but that don't help me at all- I have n't got a vernier to measure the head thickness either

 

Well the only way u can be sure is with valve cut outs and knowing the thickness of the head, althou with valve cutouts shouldnt matter really the thickness would affect how much boost to run due to affecting the compression ratio

 

I went thru this problem when we built my one last time ! in the end we had valve clearances cut out ! simply because we had the head skimmed and were using bd10 and bd14 cams ! it was simply a precautionary measure as the last thing we wanted to do was bend valves or damage seats or seals ! forthe sake of £20 per piston its gotta be worth it !
ive had it done on the new one aswell !!

 

my head is 138.7mm with 7.2/1 cosworth pistons with valve cut outs
im running a pair of bd14s and get no problems at all.
I would put cut outs in those pistons though if the engine is in bits.....