5 replies to this topic

[Rick Anderson]

I have a new Piper 255 cam and it is fouling on the rod and/or ARP bolt head but ONLY when the timing chain is off. It is fine and they are nowhere near each other when the chain is on and the cam is timed. The cam is not binding and is sitting in the oil pump correctly with 3 thousandths endfloat per specs. Nothing else seems to be off. It is really not a problem unless the timing chain breaks but is it indicative of another problem? Thanks. 

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Edited by Rick Anderson, Yesterday, 07:36 PM.

[imack]

Completely normal

[Rick Anderson]

Completely normal

Thank you! I just about shart when I saw it because everything has been going so well otherwise. Good thing I caught it and didn't damage the lobes. 

[Earwax]

It may be a bit early for my brain cells but i can't recall ever seeing this. I am now wondering in the numerous times the crank gets rotated when building the engine - whether all the turns after the cam goes in are with timing chain on? 

 

This is also from the man who has conniptions when the gears and synchros dont do their thing until all tightened up - so maybe a bit of a worrier but  I would love others to chime in please

[Spider]

It may be a bit early for my brain cells but i can't recall ever seeing this. I am now wondering in the numerous times the crank gets rotated when building the engine - whether all the turns after the cam goes in are with timing chain on? 

 

This is also from the man who has conniptions when the gears and synchros dont do their thing until all tightened up - so maybe a bit of a worrier but  I would love others to chime in please

 

As Imack says,,,, normal.

With the 8 ports heads, as all chambers and port arrangements are the same, they run a different sequence cam. For 5 Port it's E-I-I-E-E-I-I-E, where as for the 8 porters, it's E-I-E-I-E-I-E-I.. Due to this, regardless what rods one runs, they will foul on the cam. It's necessary to run S type Rods and modify them for cylinders 2 and 4 so they don't foul.

 

[Shooter63]

It's also the reason that when you build a 16v conversion that you grind/machine the camshaft lobes off.

Shooter