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How to time unknown cam?

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Wondering how I can work out the correct cam timing for an unknown specification cam?
Cam was in the mystery package 2.0L SOHC Ford Pinto I bought a while ago. It’s had a bit of head work done with some porting and larger valves. Had 48 Delorto sidies and sexy looking banananana extractors. I plan to start running it on the 40DFAV V6 carb off the old 3L Essex as I know it’s good, rather than rebuild the old Delortos first up.

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Markings on the nose of the cam appear to be “308D   308D   06    9341    JG”

I have no idea whose cam it is and can’t find any references to any of these numbers.

looking at specifications for pinto cams the timing for full lift on number one intake varies from 113 degrees for mild to 104 race cams, but do not follow a linear progression. Different makes and cams tend to move around a bit.

The valve  lift is 11.13mm inlet and 10.19mm outlet at the valve with std clearance so more than standard, but not wild.
Some posts on the UK sites suggest timing it with equal lift for inlet and exhaust at TDC on #1 like this post. #http://www.turbosport.co.uk/showthread.php?t=836432
This would equate to 105 degrees which seems pretty advanced?

Here is a graph of the lift I made from measuring the valve lift. Degrees is crank not cam degrees. Lift is in thou and measured off the valve retains with standard clearance to cam.

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Any thoughts or tips on where I should put the cam timing to start with?

 

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You can't time it correctly without a spec card.

I think the cam places like Kelford etc can measure it and make you a new spec card.

Or line the marks up and call it good.

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Mark where the valves hit the pistons, then play around with it on a dyno?

 

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^  This.     very good chance you will end up with better results, than if you had the cam card and used recommended settings

otherwise i would go slightly more lift on intake than exhaust at tdc

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Thanks guys!

21 hours ago, Valiant said:

You can't time it correctly without a spec card.

I think the cam places like Kelford etc can measure it and make you a new spec card.

Or line the marks up and call it good.

The cam keyway is well out compared to a standard cam so the factory settings don’t work.
 

20 hours ago, Yowzer said:

Mark where the valves hit the pistons, then play around with it on a dyno?

 

Yeah, definitely trying not to get an interference fit with the valves...

 

18 hours ago, kpr said:

^  This.     very good chance you will end up with better results, than if you had the cam card and used recommended settings

otherwise i would go slightly more lift on intake than exhaust at tdc

Thanks, slightly more lift on the I left at TDC sounds reasonable.

3.86mm lift on the inlet is 3.45mm lift on the exhaust as it closes and 103 degrees advanced. Is this the sort of figures your are thinking?
 

11 hours ago, locost_bryan said:

There's a spreadsheet of Pinto cams here https://www.classic-ford.org/cfp/tm.aspx?m=20701

There are only two cams listed with 308D inlet and exhaust (neither match your other codes), but could give you some ideas for timing.

Thanks, I had found this spreadsheet, however my cam has more lift on the inlet than the exhaust and I couldn’t find many like that. Most have the same lift, and a few have more lift on the exhaust?

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Hello MC .... You could see what lobe centerline the cam was ground at ...measure the cam lobes & not the valve gear , peak lift IN / EX  I would bet this is 110 deg.    from your graph it looks like timing is symmetrical, so a good guess is that the timing will be pretty much the same on either side of overlap ....don't forget to allow for rocker ratio and lash when measuring at the cam and allow .006" valve lift before you measure deg 

most cams at or under 280 deg are usually pretty much symmetrical when looking at a deg wheel diagram 

here's my guess 30.70 : 70.30 at TDC  ....you can move the cam either side to suit but all you do is move the torque / power down or up the rev range , ADV = low   RET= up

It doesn't really matter what the numbers are, you will soon see what the cam is ! just make sure the overlap is equal both sides of TDC 

you can double check with soft putty / plasticine between piston / valve   

 

 

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