Timing. Help please

[DrKai]

Trying to sort timing. Made a marker. Put an upside down follower on top of the one fitted so the dti can reach. I've got tdc I'm the middle of dwell for piston 1. I have a Kent th6-6 cam which has full lift at 103 for inlet and exhaust.. Set the inlet to 103 after tdc. Thought lovely job done just check it with exhaust. It's about 10 degrees out. I've been fiddling for about 3 hours. If I fix one it puts the other out and so on. Redone tdc over and over. Just can't get it. Any ideas?

[yorkshire_spam]

How did you get tdc? I've just done this a few weeks ago on my engine build - I found using a piston stop and "split the difference" a lot better than trying to find the middle of the "no movement" period for TDC.

I set mine by max lift on inlet, then spec sheet had a lift at TDC that I checked against. Final check was that as the cam was symetric I could check for equal lift on inlet and exhaust at TDC.

 

[DrKai]

I did the middle of no movement. I've given up for now. I'll make a piston stop and see if I do any better :s

 

[DrKai]

Well after five hours I think I've worked it out. This is the spec sheet. States timing is 42/68 and 78/32 and full lift 103 for both. As far as I know lobe centre calculated at (42+68+180)/2-42 for inlet which is 103 as expected. but for the exhaust (78+32+180)/2-32 is 113! Exactly what I was getting! So I think I've spent half my day chasing an error that didn't exist!

[yorkshire_spam]

Easily done, I spent half an hour thinking 90+10 = 110 on my timing gauge!.... NOPE, go past 90 and then 20 more! Not 10.