Got a new head guys and it has a Piper 285 t2...
Did all the usual prior to fitting/inspect valve seats/leak down test etc.
But,-
Very difficult to start + after eliminating the usual suspects timing, fuel etc
I checked the compression....My previous 158psi across the bores is
now 120/125. Have any of you genius's experienced similar problems with this cam?
It has the standard Ford cam sprocket fitted.

 

Did you soak the tappets in new oil. Not 100% sure but think your supposed to compress them and try and get all the air out and some oil in new tappets. That way when you try to start the engine the tappets open and close the valves properly until the engine starts and gets proper oil pressure up to the head.

Also have you managed to get the engine to start? and if so did you run the engine @ 2000 rpm for 20 mins as per cam run in instructions ?

 

A wild cam will naturally give lower compression pressure at low revs because it shuts the inlet valve much later.

 

its possible that u might have the cam timing still out by 1 tooth 5 degrees

 

I was thinking along those lines.Perhaps if the blanks Piper use are deliberatly inacurately machined to nescesitate the purchase of
adjustable cam sprockets/from them of course....the timing is
otherwise correct.

 

Hence the original question. Cos obviously in life I think I'm unique....
But I can't believe this experience is.

 

I think my answers are transparent for some reason...
I believe Stu had this problem too at some point. I wonder if there ever was a solution?

 

u need a vernier to get it timed in properly, before you can even think about looking at other causes. Infact, you can take the key and use the std pulley to time it in.

 

Not quite sure where we're coming from Rick/it has standard pulley on it and is (as Mr ford intended) timed correctly.HOWEVER (as I suspect) do Piper
deliberatly mis time them during manufacter?

 

In a sense, yes they do. Maximum lift on no one inlet should be at 114deg ATDC. With the std pulley, it won't be anywhere near this. The valve may still be open on the compression stroke, hence low readings/not starting.

 

Many thanks for that Rick. I'll have a little play around with the tensioner to simulate +/- a degree or two and see if it makes a difference and then either get an adjustable or rip it out and stick it on ebay.

 

its a good cam, so worth getting it timed in properly.

 

Would the cam being timed without a vernier create smoking? cause ever sinse i fitted mine, run in and pre oiled the lifters etc its been smoking like a chimney. I timed it smack on tdc at n01 by the way

 

Only reason it would do that is if u disturbed the valve stem oil seals.