Piper Cams

[Jepp78bertone]

Hey folks,

I'm trying to select a camshaft grind for my engine build and came across an old post where someone references the Piper BP300 cam as being a sweet option.

https://xwebforums.com/forum/index.php?threads/hot-1300-build-gearing-question.35171/page-2

I sent the specs to my cam guy and he is asking what the duration at .050 is. The piper cams Spec sheets don't specify. Does anyone know? Spec sheet says Duration is 290 degrees for the PB300 & 288 degrees for the BP285.

Also, does anyone have any experience with these cams?

I've attached the Piper Cam's advertised Spec pdf's

 

[fiatfactory]

you've clicked on the "reprofile" link... which I guess means these are regrinds... if it has 2mm more lift, that generally means the base circle has been reduced by the same amount.

The "other" cams listed don't say they are reprofiles... well they don't expect a return / core charge .. so I would be sending Piper an email asking 2 questions... is this a billet / standard base circle cam or a reprofile? and whats the duration at 50 thou...

The 300 has a lot of lift at tdc, good full lift of over 11mm, so plenty of potential without a huge overlap.

SteveC

 

[RZSR X]

I sent the Piper cam link to my engine builder of my high perf 1300 and he instead liked the 37/71 at Vicks. Not a regrind and half the price.

 

[Jepp78bertone]

So I emailed Piper cams and they got back to me about what the duration is at 50 thou.

Cam Duration at 0.050” for the BP285 = 243°


Cam Duration at 0.050” for the BP300 = 258°

 

[Mark]

My issue with the 37/71 is it has a reduced base circle necessitating one of several mods to compensate. Not something that should be required with this profile. It is in essence a “reground new cam”. I sent it back when I discovered this as it was not spelled out in the description when I ordered it.

I sent the Piper cam link to my engine builder of my high perf 1300 and he instead liked the 37/71 at Vicks. Not a regrind and half the price.

 

[Ulix]

What is the max lift cam with stock base circle that can actually be installed?
I was under the impression that a cam with, say, 10.3 mm lift on a stock base circle would not fit through the holes in the cam tower.
Hence, it needs to have a reduced base circle.
(Maybe I am wrong though, since the euro stock cam has 9.9 mm lift).

 

[RZSR X]

My builder is aware of the smaller base circle but he likes it because the base circles are All exactly the same.

He didn't want any variance whatsoever and any mods to use the cam were no big deal to him.

 

[rx1900]

What is the max lift cam with stock base circle that can actually be installed?
I was under the impression that a cam with, say, 10.3 mm lift on a stock base circle would not fit through the holes in the cam tower.
Hence, it needs to have a reduced base circle.
(Maybe I am wrong though, since the euro stock cam has 9.9 mm lift).

Hi Ulix. Hope all is well with you !!

I would tend to agree with you 100% - as usual....

My Genuine Fiat Workshop manual lists the smallest cam journal that the cam lobes must pass through as being 47.980 to 48.050 mm in diameter. I think we can take that as fact....

It does not list the cam base diameter....BUT....a search here revealed 2 posts from Steve C. stating the OE cam had a base circle of 28.0mm.

Thus...if that all is true...then surely the largest lift cam - that maintains the stock base circle - would be about 9.99mm. Any more lift than that and the cam lobe would not pass through the cam bearing journal !!!

Thus...a cam....for example the Vicks 37/71 with a stated lift of 10.5mm would absolutely have to have a reduced-from-stock base circle....

 

[dllubin]

Hi Ulix. Hope all is well with you !!

I would tend to agree with you 100% - as usual....

My Genuine Fiat Workshop manual lists the smallest cam journal that the cam lobes must pass through as being 47.980 to 48.050 mm in diameter. I think we can take that as fact....

It does not list the cam base diameter....BUT....a search here revealed 2 posts from Steve C. stating the OE cam had a base circle of 28.0mm.

Thus...if that all is true...then surely the largest lift cam - that maintains the stock base circle - would be about 9.99mm. Any more lift than that and the cam lobe would not pass through the cam bearing journal !!!

Thus...a cam....for example the Vicks 37/71 with a stated lift of 10.5mm would absolutely have to have a reduced-from-stock base circle....

That sounds correct. I've got a cam with 10.6 mm of gross lift and it has a smaller base circle for that reason even though it was cut on a fresh CWC steel billet.

 

[lidox19]

I have a Piper 285 billet cam in my 1600cc. I didn't have to shave the cam carrier or fit excessively thick shims so the base circle can't be reduces by much if at all. As it is fitted it would be difficult to measure it now.
The only problem I have is I should gone for the 300 !
Email them. They were very helpful when I contacted them.