Uprated camshaft: Experiences, recommendations?

[greyelephant]

Dear experts

After having since purchase about 22 years ago a machine not running as smoothly and not having the power this Buick developed small block alu-engine should have, a probably blown head gasket (or worse...) since Sunday makes me solving the first problem, probably caused by a worn camshaft, as well together with the second, when everyhing has to be opened up anyway. javascript:add(%22%20:'(%22)

I would like to take the opportunity and consider a useful and practical improvment of engine characteristics without too many changes or (hopefully not...) a rebuilt. This car with a BW 3-speed auto.-box is rather heavy and no race car (to which it also should not be transformed, beware...), but off course I would like to change the camshaft for the best and ultimate available. javascript:add(%22%20:%22)

Having read "The Rover V8 Engine" and "Tuning V8 engines" by David Hardcastle, it is nevertheless for a non-mechanic quite impossible to decide and understand in detail what would be the best solution and how differences could be felt when driving. What I could figure out is, that it would definitely has to match the auto.-box and should likely produce more torque at a wider range, but not on top but at the bottom as these never were high-rev. engines. javascript:add(%22%20???%22)

My research led me to Kent H180 / H200, Piper V8BP255 / V8BP270i which I suppose might be suitable.

I would therefore appreciate some coments about pro's and con's, experiences, alternative possibilites and recommendations of persons who have already made such slight improvments on their P5B (or ev. P6B or SD1 V8, which are quite similar I think). javascript:add(%22%20:-*%22)

Many thanks in advance and thanks for all the best wishes for my Elephant to get well soon.

Peter

[spivomatic]

Try these people www.v8forum.co.uk/forum/index.php?sid=341fca1a290146bf496ddd6f712fbe6b
sure to help.

[spivomatic]

Or this may be helpfull ezinearticles.com/?Rover-P5b-Engine-Conversion&id=3144238
good luck

[greyelephant]

Nobody out there with an advice and some information? Did already contact V8forum, but so far same "result"...

[johnwp5bcoupe]

Have a word with Ray or Rob at www.v8developments.co.uk/ if you are a club member you will get 5% discount on any purchase.

[tomcgn]

Peter,

with the P5B you'll want more torque low-down in the rev range rather than more power at the top end. The easiest way is to fit a high torque camshaft and heads with bigger valves. It might also be necessary to fit different needles to the carbs. It's not a terribly complicated job to swap the camshaft but just a lot of work.
It worked fine with my car, noticeably more grunt.

it does come at a price of course...

regards
Tom

[lutz]

Hi there,

this topic was years ago. But I was confronted with the same question this year.
so here is the result of my search... in the book "How to power tune your Rover V8 engines" is a is a chapter about camshafts.
After that Roadworthy engines that need to deliver good fuel economy and a wide power and torque band off-idle require valve durations in the 255-270 degree range.



Piper Cams is a good example to start with as they offer a wide range of "smooth idle" cams. The first of these hydraulic cams is the V8BP255 which, with its 10.9mm valve lift, is a direct replacement as the standard valve springs can be retained.



As a direct replacement for the standard item, Kent Cams offers its H180 camshaft. It is a very mild cam and, like the Piper Cams V8BP255, serves its purpose very well.

Please note: at 0.441 inches/11.2mm, the stroke is above the maximum and therefore require replacement of the valve springs.



If your choosing a camshaft with a valve durations over 270 degree, then the idling becomes more and more restless with a larger angle.

Hope hope the above helps.

Best regards
Lutz

[p5andrew]

During the course of a rebuild of the engine in my P5B, I fitted a Piper 270i camshaft and new lifters, this camshaft having been strongly recommended by the Lloyd brothers of Lloyd Specialist Developments.  They reckoned that this particular profile was best for general use without sacrificing idle quality.  It has proved very satisfactory.

When fitting ANY replacement camshaft or other valve train components, do make sure that the lifters/tappets are empty of oil and that the tappet pre-loads are the checked and adjusted.  This is ESSENTIAL!  

Hope this helps.

Andrew

[enigmas]

There's nothing particularly wrong with the factory fitted camshaft. As for the engine it's an undersquare design (shorter stroke than bore diameter) so has quite a high rev limit, around 5,500 rpm IIRC. Most GM V8s of the period were redlined at 4400 rpm as is my P76 powered MK3 coupe which is a square design engine (bore and stroke are both 3.5").

The stock standard P5B that I'm currently working on even after all it's years of storage and lack of regular scheduled maintenance still pulls like a train...much to my surprise.
Check out the text and vids on camshaft/lifter issues here, bottom of page...https://roverp5.proboards.com/thread/12128/mikes-loon-saloon?page=5

Before throwing out a good, viable working camshaft take a good look at the ignition timing. A worn distributor running points ignition will produce erratic firing cyl to cyl. To check this, simply turn the engine over until the distributor rotor is on one of the points lobes (points open). Now grasp the rotor between your thumb and index finger and push it backwards and forwards. If the points are seen to open or close further, then this is a sign of a worn distributor lobe spindle.

Bumping the static timing up often as far as 10° BTDC will generally produce more instant torque off idle, especially with an automatic.

Fitting a good quality electronic ignition module (very inexpensive these days) will produce even firing and improved running overall with negligible maintenace.

As for fitting higher lift, longer duration camshafts also be aware to check the valve guide heights and obviously coil spring bind. Don't guess measure and research before these alterations are required.
With a fresh torque camshaft fitted there shouldn't be a need for all these measurements as most will drop straight in.

Focus on reducing back pressure (a free flowing exhaust system), and a quality 3 angle valve job for the cyl heads. The ports should be cleaned of imperfections, ridges and flow inhibiting obstructions, but no enlargement of the ports as this reduces airflow/mixture velocities. A textured but smooth surface, is what is required.