Setting up Pinto cam timing

[esky boi]

Hmm well im just putting the belt on my pinto now too.

But im having a major problem getting the cam timing setup properly, like it will NOT line up. It either sits about 8 degreees advanced or 8 degrees retarded

Ive had the head skimmed 60 thou and I was thinking this might have something to do with it??

Anyway, ive heard you can have the cam timing slightly advanced/retarded to get more power on a pinto? but with that much taken off the head that probably wouldnt be a good idea, as piston to valve clearances could be getting abit close aye?

RT?

[RT]

Since you've skimmed your head the distance is less so this will affect your timing. 8 degress sounds like a lot though as I think one tooth is 6 degrees.. dunno really about this sort of shit.

But you may have the wrong belt for starters as the Sierra belts have 3 more teeth than the Cortina belts.

Furthermore, sometimes the factory settings aren't correct.. in fact they can be up to 9 degrees out! This is why most pinto builders invest in a adjustible cam sproket so they can get it where it should be.

Typically you want to go from 6 degrees retard to stock or 2 degrees advance for increase up to 11 bhp. The gain of an adjustible sproket depends on how out your factory setting are. So you can advance up to 8 degrees sometimes if your settings are already out by 6 degrees for instance.

I would see how it runs 8 degrees advanced. But definately buy an adjustible cam sproket so you can get it spot on where it runs best.

From Vizard:

[Stacov]

interesting read. How do u tell if the cam timing is advance / out?

Lets say u have it perfectly lined up with its arrow / hole what way will advance it?

Sounds stupid huh but alot of people get confused like myself

[RT]

the cambelt rotates clockwise so moving the sproket in this direction will advance it. You can tell by using a timing light connected to no. 1 plug lead and checking when it fires against the timing marks. It pays to use some white-paint or twink on the timing mark to see easier.

I suggest you boys get a copy of 'How to modify Ford SOHC engines by David Vizard.' it's like a bible for this sort of shit. Get it from the Library and photocopy the bits you need.

[Jerm]

Has your cam been reground? if it has it may need dialing in.. well Xflow ones do i'm not sure abotu OHC ones but i guess an adjustable cam wheel would do the trick...

https://www.burtonpower.com/default.aspx

[esky boi]

Yea, very good read there. Might just leave it advanced 8 degrees then and see what happens.

Like since the head is skimmed would this have caused the timing to retard slighty (meaning 8 degrees would really be something more like 6??) or does it advance it, so I could really be running like 10 this shit's pretty confusing lol.

How much can it be advanced/retarded before im in danger of the pistons hitting the valves?, ( with 60 thou off the head)

Jerm: I just have that FR21 cam. Dont think that would really affect the timing not lining up, or would it??

[Guest Eddie W]

Since you're able to specify how much you're out on the timing, I presume you are degreeing the cam properly. Never take the factory's TDC as gospel if you want it exact. With the degree wheel on the crank and a wire pointer bolted on that you can bend if necessary you find the true TDC by using a spark plug with the electrodes ground/broken out and a steel extension welded in. Start with the crank at BDC and fit the plug, turn the engine gently by hand until it stops with the piston against the plug, take the pointer reading on the degree wheel, turn the motor in reverse until it stops again, exactly between the two readings is true TDC. Remove the plug and rotate the motor until the pointer is on this reading then back the crank nut off and rotate the degree wheel carefully until the zero mark is lined up with the pointer and gentle nip up the crank bolt to lock it there. You now have the degree wheel zeroed exactly on TDC.

Most reground cams should come with a spec. that gives a dgree reading for max. lift, usually somewhere between the low 90s and the mid 100s. Beg, borrow or steal a magnetic base DTI and set it up on no1 inlet. With the crank tuned so that the degree wheel is on the cams correct spec you rotate the cam until you have the max lift reading and that should be the correct timing.

From there you may need either an adjustable sprocket or it sometimes possible to redrill or drill out and fit eccentric bushes if the variation is not too great. Over to you. Since you have gone to the trouble to get an accurate TDC, check it against the factory markings. They may or may not correspond. Good luck.

Sorry for the long screed.

Eddie

[Jerm]

If it is a regrind yes....

i would think skimming the head would advance it slightly... but i'm not realyl sure.

[esky boi]

Hey cheers for that Eddie, thats some good info there. Ill definitely give that a go aye

[RT]

or if you're a garage cunt like me you can stick a crew driver in the sparkplug hole and 'feel' for TDC

[esky boi]

Haha yea thats another way I spose

[Defcon]

Lol, i shon a torch down the spark plug hole and watched it come to tdc

[Guest Eddie W]

The point is that you can't pick TDC itself by looking or feeling as there are some degrees at TDC where the piston has no or minute vertical movement. By stopping it a set amount either side and dividing accurately, you get it true. The crank movement is magnified by the radius of the degree wheel.