Changing Cams in a Volumex

[marcoos_1]

I'm considering changing changing the inlet cam on the volumex. How hard is it, and do I need shims etc? I guessing I can take the cam boxes off and do it in situ?

[mudhut]

Quite an easy job in theory but can be fiddly.

You will need to unbolt the cam carrier as you need to relieve the load on at least some of the valves.

When you reassemble, you need to have measured the clearances with the existing shims (which themselves might need "micing up"). You can then calculate whether you need different shims.

If your new cam uses the same base circle diameter as the original, you are likely to be fairly close with the existing, but the cam carrier gasket settles one or two "thou" over a period of a day or so.

If you have a reprofiled cam, then the cam base circle will be too small for the existing shims and gasket leading to excessive clearances. Thicker shims are hard to find I understand and many people rebuild the head without the gasket under the carrier and then apply silicone RTV compound. Clearances are then back towards what they should be with the standard sorts of shim thicknesses.

Some more info on Guy Croft (http://www.guy-croft.com/viewtopic.php?t=14) site inc. the warnings about running in cams and bending valves.

[guy mayers]

My old Volumex was buit by Barry Waterhouse. If my memory is right he used Beta 1600 cams and reprofiled to give slightly longer duration by lopping the tips of the lobes off. This obviously gives more clearance to the shims which was sorting by machining a corresponding amount off the base of the cam boxes. This was considerably cheaper than new cams.
Guy

[Shaun II]

I think the easyest change is to use the Lancia IE inlet cam, a fiat 130TC if you can find one or even one of Guy Crofts specials. It's not a difficult job but can be a fiddle as the cam boxes are inclined. The shims like to slide an get stuck between the cam and cambox lip. The SEC club has a collection of shims and the two special tools donated by Sando are in my posession, let me know v.soon if you need to borrow them as I'm travelling over on Tues. I never got on very well with the tools and just took the cam box off again.

Guy Crofts site is a great source of info, there was quite a bit on the Lancisti site also.

You may need to look at changing the std carb, I'm told that a 130TC inlet cam, std exhaust, an overdrive pulley and a single 45DCOE should be giving about 160bhp.

[marcoos_1]

Thanks Shaun,

I think I will need the tools. If you could send them to me then that would be great. Just let me know postage/packaging cost etc.

My carb is down at Guy Croft at the moment, and what I want to do is swap out the aftermarket, re-profiled cam that I have, and get Guy to install a standard cam. His oppinion is that we will get far better results on the set-up that I have with a standard cam. (I'm taking off fuel injection and putting on a 45DCOE). So'I'll need the tools to do the shims etc.

I'll PM you my address.

Many thanks,

Mark

[Martin K]

My tuppence worth.....

What is the duration and lift of your new cam?

I don't think there is much to be gained from increasing the duration over the standard 232 degrees @ 0.81 mm lift of the VX inlet cam unless you are planning a higher speed for peak torque and peak bhp than you enjoy at the moment. For example, the 037 used an inlet cam of 256 degrees but it's peak power at 8000 rpm and peak torque at 5000 rpm - probably not what you want - and largely influenced by the cam timing, which gives 52 degrees of overlap.

The standard 2 litre cam has a duration of 242 degrees, I believe, and would probably work quite well with the standard VX exhaust cam, but it doesn't have such as much lift as the standard VX inlet cam.

However, the lift of the standard VX cam is also lower than ideal for the larger inlet valve that the VX has over the n/a twin cam. If you have a cam that gives a VALVE lift of 11 mm then you should see some useful power gains, as long as the head will flow the required amount of air. I cannot find a standard Fiat/Lancia cam that offers such a lift without a much longer duration than you require, so a special grind would be required - maybe the one you have meets this spec? Whatever cam you decide to use, I suggest that timing should be such that you close the exhaust valve by TDC or no later than a handful of degrees after and limit overlap to 20 degrees or less, as the more overlap the less will be your bottom end torque.

It would be nice to know what you finally decide on and what power the finished engine delivers once set-up.

Good luck!

Martin

p.s. The 1600 cams Guy mentioned are 240 degrees duration, I believe, and would give an overlap of 13 degrees with the standard VX exhaust cam or 20 degrees if both cams are from the 1600. I believe they have a cam lift of 10.4 mm. If you could get a bit more lift but retain the timing, that would be a good choice in my opinion. Maybe that is what Barry W did with the cams, Guy?

p.p.s. Just seen the 130 TC cam spec - looks ideal!

[marcoos_1]

Thanks Martin,

At the moment the car is producing 130bhp at the wheels, measured on the local rolling road. It has an Emerald ECU and running a home-made fuel injection system which I'm not sure is offering any benefit over a standard carb set-up. I queried this with Guy Croft and he said that we are far more likely to get better figures from changing back to a 45DCOE and a standard inlet cam from a Vx. I'll probably keep the Emerald for the ignition, but quite fancy trying it back with a carb set-up and standard cam, at least this will give me some benchmark. The head work was done buy Guy croft originally (porting etc) but he did not supply this aftermarket cam. My plan at the moment is to remove the cam box, send it down to Guy with the standard and non-standard cam and let him see what he thinks would work best.

The main problem with the car at the moment is that it's not pleasant to drive at low revs, and tends to be quite sputtery. The other issue is that the four injectors are mounted together, outboard of the blower. To improve on this and really get the benfit of injection I would need to fab up an inlet manifold with enough space for the injectors and rail.

Does anyone have one of these 2.0l cams? Just incase I need one...

I'll keep you posted on how this develops. I want to try and complete the work quickly, as I don't want the car off the road. Stoneleigh is looming......car must be ready.

[Sando]

Thanks Shaun,
I think I will need the tools. If you could send them to me then that would be great. Just let me know postage/packaging cost etc.


:) ......Hope you joined the club like you said earlier then Mark :eek: :) ;)

Bit of a rant now. Sorry to hijack your thread Mark......
Just one of the many benefits of being part of the club. With the Supersite forum being an open forum, information is freely available, but tools belong to the club membership.

These are rare and valuable tools so we need to keep tabs on them within the club. (That includes the Beta wheel bearing locking ring tool mentioned earlier this week too amongst others.) If you can find them they would cost a lot more than club membership does!

Swamprat33 can give anyone further details, or come and see us at one of the events.
cheers
Rob

PS 130 TC cam is the one to go for! :)

[marcoos_1]

No need to panic, I'm a fully signed up member now! Did it last week, so hopefully getting some info through from Tim soon.

A word on club membership........(I apologise in advance for this, but it is afterall my own thread I'm hi-jacking!)

In the past I've been a member of the Dutton club, the GT40 Owners Club and the Scottish Kit Car Club. With the exception of the Dutton club which was really well run and worthwhile, the others have pretty much been a complete waste of time and money. The basic idea of joining a club (for me anyway) is to have a forum for people to get together and share problems, advice, experience and resources, as well as any social benefits. This was traditionally done through the club mags (if we had enough entries).

Now, things have changed and we have these internet forums which are amazing, and far more productive for me than my previous experince of club membership. Advice is real-time, 'articles' are forthcoming from most (it only takes a few seconds to type up a thread, as opposed to sitting down and writing an article.)

Having said that, I am now looking forward to membership of the Stratos Owners Club. It's something I should have done before now, but in many ways it feels like we are all members on here anyway! I guess I did not appreciate the additional benefits of SEC membership and, to be honest, my main reason for joining was to get my car alongside the other guys at Stoneleigh on the club stand (eh...you will note that I am not placing my car on the Scottish Kit Car Club stand....) Now I find I may need some tools and ....... low and behold.........I find out these are available to club members - brilliant! This is what club membership is all about!

So, I guess my point is, internet forums are free for all and helpful, but there is a great deal more to had in membership of a truly active club!

Some come on....if there are any others out there like me that just didn't get round to it.........then join!

Looking forward to meeting some of you in the field at Stoneleigh.

[marcoos_1]

Ok, now back to the cams.........

anyone got a 130TC inlet cam I could buy if I need it????

[Shaun II]

I eventually found a hen's tooth but still looking for a 130TC cam. Having said that I did buy a 130 TC engine that had a volumex head casting but the cams looked standard - will go and check correctly if I ever get time.

As for the shims and things, I don't suppose anyone could pick them up from near J13 of the M5 and take them up to Stoneleigh?

If not I'll try and post on Monday if I get back from the Tour of Cornwall in time.

Best thing I ever did stratoswise was to join the club, the cd with back issues and the other members experience has been a big boost. It's a great club but most of us should do more to help out a bit!