Cam

Just received from an ebay seller a cam purported to be a Dunstall.
It's marked between the tacho drive and the first lobe:
PD-05
H.955
WEC

THe problem is it's evidently been re-profiled, and not particularly well.
The lift is huge, the duration is small, and I'm concerned it wont be particularly kind to a standard valvetrain
Ex. 0.395"
Inlet 0.434"

Photographed next to a 2S Combat cam for comparison.





What the **** is it!? - I'm fairly certain it isn't a Dunstall. Not any more, anyway :roll:

As an aside,

I spotted this rare visitor to Lincolnshire yesterday



- the bike sounded awesome, but I think the CRMC would make the spectacle more enjoyable for all if the classes were arranged to keep the TZs and RGs in a separate race from the big twins - just my biased opinion

Andy,

I have the same cam, like new not reprofiled.
The lobes are "sharp" looking (valves will spend less time at full lift), especially the exhaust lobes.
The lift on the inlet lobe is approx. 1 mm more and on the exhaust lobe approx. 2 mm more than a 2S.

KR
Bert

Bert,

Interesting - I was wondering if I'd been sold a duff prototype or something.

Do you know who came up with that grind?
Have you tried it, and did you have to do anything with the valve springs to prevent them getting coilbound?

Finally - is it any good!?

B+Bogus said:

Bert,

Interesting - I was wondering if I'd been sold a duff prototype or something.

Do you know who came up with that grind?
Have you tried it, and did you have to do anything with the valve springs to prevent them getting coilbound?

Finally - is it any good!?

Click to expand...

Unless it is an modified SS cam, as is stamped, I don’t think anyone on this help board can tell you what it is without further information.

You need to insert it into an engine and with a degree disc find out where all the valves open and close.
As I have found out to my cost, I would be very wary if it was a Dunstall cam, I purchased one from his shop when he was in business, and found the opening and closing of 3 of the lobes were way out, nothing like what he what he advertised them as.

I thought Dunstall cams were always set up to run on needle roller bearings? The cam you have has a scroll on the bearing journal, so that would preclude it for needle rollers.

Cheers Richard

stockie2 said:

I thought Dunstall cams were always set up to run on needle roller bearings? The cam you have has a scroll on the bearing journal, so that would preclude it for needle rollers.

Cheers Richard

Click to expand...

A Very Good Point!

A discussion with the vendor is required, I think :evil:

stockie2 said:

I thought Dunstall cams were always set up to run on needle roller bearings? The cam you have has a scroll on the bearing journal, so that would preclude it for needle rollers.

Cheers Richard

Click to expand...

not so!!

http://www.accessnorton.com/dunstall-camshaft-t12398.html

So,

No oil feed & no needle bearings would have made it a street cam, but evidently re-profiled at some stage.
I've still to find any data for a cam with this much lift - it would be nice to put a name to it!

B+Bogus wrote,

it would be nice to put a name to it!

Click to expand...

Hows about the "supercalifragilisticexpialidocious cam".

Hi Andy,

I haven't used the PD05 cam because I'm sure the standard valve springs will not be able to cope with the lift. In the mean time I got some longer springs with special collets and keepers so I might try it one day.
It seems to me like your cam has been reprofiled. Probably not a lot of lift added but some duration. The lobes on mine look a lot "sharper".

Bert