The V8 Owners Forum -

Hi all, looking for some help on camshafts.

After investigating the cam I have in an finding it is a bit on the wild side (most likely Viper Typhoon - See viewtopic.php?t=16222) and this is possibly what is giving me less than optimal running at low RPM & idle I'd decide I'd swap it out and was going to replace with a Viper Hurricane.

Unfortunately on contacting Real Steel I've found that these are not currently available and not likely to be until end of January.
This wouldn't be too bad but experience has shown be the dates tend to push out rather than come forward, particularly with Christmas holiday in the midst of it, so I'm looking for advice on alternatives.

I'm looking for something which gives a small power advantage but will also maintain good manners low in the RPM range as it is suggested the Hurricane does so I'd appreciate any advice or experiences.
Failing that I'd rather move more towards a standard cam than higher performance (which is what I already have - No complaints at the top end) but I guess there are different versions of the 'standard' cams such as for different capacities and models. Any suggestions on which cam would work best with a 3.9 engine which has some breathing improvements in breathing, the ports and inlet manifold have been opened up a bit and exhaust is running 4 branch headers.

As always thanks in advance for any help or advice.

Hello,

see: https://www.v8tuning.co.uk/viper-hurricane

Unfortunately, it's currently out of stock.


I could recommend the Piper RP4. It's quite similar to the Hurricane and runs extremely smoothly and cleanly at very low RPMs.




It's no longer listed on Piper's website, but a friend of mine recently bought one there. Just ask them...

https://www.pipercams.co.uk/product-cat ... -long-nose

Thanks Frank. I guess V8tuning or anyone else retailing the Hurricane cam will be in a similar position to me as, if I've understood correctly, Real Steel are the source for these cams.
I was looking at the Piper cams yesterday but got confused by the numbers, it would be really helpful if cam manufacturers would agree on a common way of describing the cam characteristics, particularly the the duration, or better still produce diagrams exactly as you have done, straight away you can compare those two cams.

Looking at the graph I can immediately see the similarity in lift, the slightly greater duration of the Piper and the fact that this is on the rise of the exhaust cam and fall of the inlet cam resulting in virtually identical overlap which, from what you said on the other thread, will be the main contribution to the idle/low RPM behaviour.

I did actually look at Piper yesterday, they have a large number of RV8 cams I guess one of them is the RP4 under a new name, possibly the BP270B or BP270iB (difficult to see the difference between them) or the BP255B (milder). I'm assuming the number in the name is an indication of duration.

It's really annoying that the camshaft specifications aren't standardized.

That's also why I went to the trouble of measuring the camshafts.

I had also bought some as part of a package with other parts. New camshafts with numbers for which I couldn't find any information anywhere. After measuring them, I experienced some surprises.

The unknown ET6U (with distributor drive) is identical to the ERR5250 from the Rover P38 (without distributor drive).




I know several Rover V8s (mostly in 4x4 vehicles) that run very well with the Viper Hurricane camshaft. Years ago, they were only available from Real Steel. I wanted to order one two years ago. They were sold out then and were supposed to be available again soon. I inquired regularly for about six months. The answer was always "in three weeks."

In the end, I installed a Kent H180 camshaft. But it's only designed for torque. I don't think that's suitable for a sports car.


Regarding the Piper RP4: It's identical to the Piper 270(i)/255/285.

Explanations can be found here:

http://www.v8engines.com/engine-6a.htm


My experience with the RP4 comes from a 4.6L with two SU carburetors and a manual transmission in a light 4x4. So EFI and automatic transmission aren't really necessary.

Since displacement is known to make camshafts less harsh, the RP4 should definitely have plenty of power at the top end with the 3.9L engine.


Regards Frank

Thanks Frank

I've decided to go for the Piper 270i. They are made to order apparently with a lead of 7 days, hopefully that means I'll get it before the holidays and have some time then to get it fitted.
I checked out he spec's for their cams, lining them up side by side and it seems the only candidates were either or the 270s or the 255, I think the 270 is the one to go for (270i) the 255 may be better for idle and low RPM but the 270 will hopefully be 'good enough' and still keep some power at the top.

Seems like the 270iB and 270B are the same grind with a couple or three degrees different advance between them so with a vernier timing wheel, which I believe I have, either could do the same job.

Oh, it also appears the "i" is for injection engines while the B is for carburettor. So the "i" has it.