2000 Camshaft Options?

[carboy0]

As a newbie to the big Saloon, I am learning all the time about my new car & engine.  Can anyone advise on what camshafts work well in the 2000?  Discounting the standard one for a moment, do for example 2.5PI 150bhp camshafts help the 2000 or is that a mismatch?  Then there the aftermarket Piper, Newman etc.etc. options.

Of course there is the option to drop in a 2.5, but having driven one recently,I prefer the rev-ier  nature of the 2000.

I saw this table on the Chris Witor website, which lists the Triumph cam shaft options and it prompted the thought process

https://www.chriswitor.com/cw_technical/camshaft_applications.pdf

[Steve AKA vitessesteve]

Different cams have different characters.  For example so called race profiles will add more power but both narrow the band when power is at max and tend to make it available at higher revs.

Some questions: What style of use are you looking at?  Are you considering changing the exhaust system too?  

[Matt George]

Saloon PI cam (308778) would be a good option. I have one in my 2500 on SUs and it performs very well. More 'oomph' than standard but still plenty tractable and fine for a daily driver. 

[Matt George]

Oh, and as Steve mentioned above, a sports exhaust system will also let the thing breathe better and improve performance, too. Plus a head skim to up compression while you're at it –  welcome to the slippery slope of saloon ownership/modification!

[RobPearce]

The 2.5PI 308778 cam is the same as Vitesse and GT6 - it works well on the 2L. A Mk1 saloon will have a restricted inlet manifold and you'll get some benefit from the (slightly less restricted) Vitesse one. As Matt said, the cam would suit slightly higher compression, too, e.g. from a Vitesse/GT6 head (may have bigger valves, too).

[Nick Jones]

Quoted from RobPearce-

The 2.5PI 308778 cam is the same as Vitesse and GT6 - it works well on the 2L. A Mk1 saloon will have a restricted inlet manifold and you'll get some benefit from the (slightly less restricted) Vitesse one. As Matt said, the cam would suit slightly higher compression, too, e.g. from a Vitesse/GT6 head (may have bigger valves, too).

Another vote for the 308778 cam.  Same profile used for Mk2 GT6 and Mk2 Vitesse (2L), Mk1 2.5PI saloon and earlier Mk2 PIs and also Mk3 Spitfire.

You don't say which 2000 you have, but the earlier Mk2 engines are very similar to the Vitesse/GT6 Mk2 with the cam profile and carb needles being almost the only differences. Later Mk2s have an even less sporty cam than the early ones and lower compression.  Some may also have smaller exhaust valves but this makes little practical difference until quite high states of tune.

The same cam works well in the Mk1 engines, especially in conjunction with a bit of fettling of the inlet manifold and head ports.

Chris Witor also does a version of the 308778 cam with a bit of extra lift on the inlet side which is reckoned to work well.

The "150 bhp" TR5/early 6 cam isn't ideal for 2L engines on carbs (unless 3 x webers/dellortos) and will give lumpy idle and low speed running.

Other than that, it really depends what you want from the car and what other mods you have planned?

 

[carboy0]

Ah, should have let you have more information about the car.  It’s a 1971 Mk2 2000 Saloon, originally single carb, but now on twin HS6s, with the long inlet manifold, remote air cleaner and elephant trunk hose and the thin plenum mounted onto the carbs.

The car has a Chris Witor stainlessexhaust system, but I think the exhaust manifold is standard.

What are my options on exhaust manifolds?  Is there something that can be mated to the stainless system?

I’m not sure what the standard cam is, but I suspect the engine is pretty standard inside, any idea what cam it should have as standard?

I don’t want a screamer, I would like something torquey and tractable, that will make the next RBRR enjoyable.

 

[Nick Jones]

Nice earlyish Mk2 then.  Would have had twin Stromberg CD150 carbs originally, not a single.  Don't think any of the 6s had a single.

If the engine is standard internally, and the factory original (the engine number might give a clue though needs to be taken with a pinch of salt after all this time as may have rebuilt or transplanted), it will have the 18/58 cam (306785) and the same head (517528) as the Mk2 GT6 and Vitesse.

The HS6s are maybe slightly too much carb as it stands.  Going for the 308778 cam, it's CW higher inlet lift variant or perhaps a Newman PH1 should make more full use of them and give you some more mid-range without loosing much (if any) from the the bottom end.

Exhaust manifold choices are the CW/Pheonix tubular 6-3-1 or a twin outlet cast one as used on TR5 and TR6 PI cars.  That works pretty well but you'll have to make/adapt your own twin down-pipe and y-piece to mate it up to the exhaust system, which is moderately tricky.

Nick

[carboy0]

Thanks for the advice Nick, I didn’t know about the cast twin downpipe exhaust manifold.

I like the idea of the 308778 cam, I know from tuning other non-Triumph cars that changing the camshaft on its own doesn’t release the full potential of the cam and that often the distributor cam and springs need changing as well.  I was thinking that switching to the dizzie, from the same car the cam came from would help realise it’s full potential or does anyone have any experience of the optimum distributor curve?

Also, the car “benefits” from the remote air filter, elephant trunk and enclosed narrow plenum, as the twin HS6s are on their long manifold - I believe that it is very restrictive.   Does anyone have any ideas on sensible improvements that will fit in the tight gap with the suspension turret?

[iggy]

Quoted from carboy0-

Thanks for the advice Nick, I didn’t know about the cast twin downpipe exhaust manifold.

I like the idea of the 308778 cam, I know from tuning other non-Triumph cars that changing the camshaft on its own doesn’t release the full potential of the cam and that often the distributor cam and springs need changing as well.  I was thinking that switching to the dizzie, from the same car the cam came from would help realise it’s full potential or does anyone have any experience of the optimum distributor curve?

Also, the car “benefits” from the remote air filter, elephant trunk and enclosed narrow plenum, as the twin HS6s are on their long manifold - I believe that it is very restrictive.   Does anyone have any ideas on sensible improvements that will fit in the tight gap with the suspension turret?

Ive recently been told the exactly the same by the guys at atspeed racing rolling road, they advised me to remove the elephant trunk and replace it with pipercross air filters fitted staight onto the carbs, Im pretty sure a pipercross PX 500 filter and base plate will fit, but  then need to take the car back to the rolling road and and get su carb needles machined and set up for the extra air entering the carbs, the guys at atspeed told me the elephant trunk is so restrictive they were confident of getting more torque and another 10 bhp from this conversion, i wished i new this before i took the car to the rolling road as its not cheap,  also i dont no how much noise these pipercross filters make , would like to here an engine fitted with pipercross filters

[carboy0]

The restrictive part is the narrow bit in front of the carb mouth.  The incoming air has to turn through a tight 90 degrees.  If there was a bigger space in front of the front carb mouth, the air could be drawn in more directly at less of a tight angle.  

Pipercross, K&N, Ramair or any other open filter will allow more air through, with the downside that there is more induction roar.  Also, instead of feeding off a cold air intake, the open filters are feeding off much warmer (less dense/less oxygen rich) air heated from passing through the radiator and/or heated by the exhaust system and the engine block itself.

On a B Series engine, I fitted a Ramair open filter fed from a cold air inlet and with stub stacks to help the air to turn more smoothly.

 

 

 

[iggy]

yes i understand Chris,  On my mk2  2500 ive removed the spacer piece under the near side engine mount, i recon i could just fit in a 40mm wide air box, have been looking at pictures mgb v8 air box plus the carb aspirated tr6 air boxes but dont no the diamentions, was thinking of adapting one of these to fit the hs6 carbs

[iggy]

Also give Chris witor a ring he will give you good advice on improving the performance of your engine, ive vastly improved the performance of my 2500cc engine by having the head skimmed down to his specific measurement and one of his CW3021ex camshafts plus his six branch exhaust manifold and single box exhaust system

[carboy0]

Thanks Gavin, will do.

[Clive]

Quoted from carboy0-

The restrictive part is the narrow bit in front of the carb mouth.  The incoming air has to turn through a tight 90 degrees.  If there was a bigger space in front of the front carb mouth, the air could be drawn in more directly at less of a tight angle.  

Pipercross, K&N, Ramair or any other open filter will allow more air through, with the downside that there is more induction roar.  Also, instead of feeding off a cold air intake, the open filters are feeding off much warmer (less dense/less oxygen rich) air heated from passing through the radiator and/or heated by the exhaust system and the engine block itself.

On a B Series engine, I fitted a Ramair open filter fed from a cold air inlet and with stub stacks to help the air to turn more smoothly.

 

 

 

I think MGB's came with stub stacks fitted. I have a pair here, bought for when I had twin HS4's on my Toledo.

If you swap the inlet manifold I think you can use the deeper filter box? That will maintain cold air feed from the plastic inlet hoses, and with a little ingenuity, fit stub stacks and K+N elements. (I had that setup on my Vitesse, the elements were kept in place by a thin bead of silicone) Downside is you loose the long tract inlet manifold. Not sure which option "wins", but CW should be able to advise.

Of course, the obvious solution to "more go" is fit a 2.5..... (or even a lexus V8)

[Matt George]

I have twin K & N pancake filters on my 2500 – they are thin and the fit is close to the turret, but everything clears. Had to cut down the bolt nearest the turret, but no other issue. Then had some BDM needles machined to suit the additional air flow. When I work out how to add pics on here I'll post a pic!

 

Matt 

[Matt George]

Try this…

[carboy0]

Thanks Matt,

When you say say you had BDM needles machined, what was done exactly and who did them?

[Matt George]

I took the car to a guy called Ron Harper in Faceby. He starts with a fatter/leaner needle (with room to take meat off) and then files down each station where extra fuel is required. Mine were richened up towards the top end of the rev range for example.

The process is obviously a bit more complicated than that, but that’s my layman’s explanation!

So, I’ve basically got bespoke needles to my application. I’d thoroughly recommend Ron – great results and not very expensive either. Car goes VERY well

[Matt George]

Oh the part number for the skinny K & N filters is 56-1400. 

[carboy0]

Thanks Matt, that’s really useful.