Motoscrubs.com

Hi

I posted a couple of years ago listing some of camshafts that I have. Well finally after packing everything up, moving house and retiring, I'm getting around to rebuilding the 250 I bought when I was 18.

I have a simple question. How do I measure the cam timing? Fitting a degree wheel is easy, but what clearance is used?
I've seen various values listed - from factory running clearance to 1 mm. I want to compare with the figures listed here in the forum to finally find out what cams I have.

Thanks

David

Hi David

take the reading at 1 mm with no valve lash . that is how Nigel and me took our readings .

Eldert .

Thanks.

David

According to the service manual, Vavle Timing is measured at 0.2mm (0.0079") of clearance for both int and exh. The rockers at 1:1 so no mutiplier. Hence reading on the stem/top spring seat is the same as reading the cam.

So set your valve at 0.2mm clearance and read the degree wheel as the indicator on your valve just starts to move. If the cam is not in the engine, then put it on centers and take your readings when the indicator moves 0.2mm from the base circle on both sides of the lobe.

regards,
Rob

Thanks Snakeoil

My cylinder head is not fully assembled, so my easiest way is to mount it and put each cam in.

thanks

David

I just did this with two unknown cams I had. I posted a pic of my set up in this thread.

viewtopic.php?f=3&t=2408&p=18035#p18035

regards,
Rob