GTAm Cam Cover

[South Africa]

Hello interested parties,

Well I was speaking about my experiences in England - it seems very expensive to manufacture items here. Machining costs are also high compared to my native South Africa. Maybe with the depreciation of the £ 'things' may change.

There is at least one company, FURIANI.DE, that makes aftermarket tappet covers in aluminium for the reproduction GTAm cylinderhead they produce and sell. They might be of assistance. One might be able to purchase an unmachined casting and machine 'to suit'.

Zagato_Olaf, to the best of my knowledge the only differences between the two tappet covers is the positioning of the oil 'filler cap'.

[maxmax]

Quote:

Originally Posted by Shire_GTV I've had this thought for a while now so it is time to share. I know there are many 105's etc running around with twinspark conversions but to my eyes they just don't look right. Would it be possible for someone to cast/manufacture a cam cover identical to the GTAm cover that with fit on a twinspark? It would suddenly make all of those GTAm replicas even closer to being correct. I know if I get around to doing a GTAm replica someday, i would want a twin spark with a period correct looking cover. Sharing is caring! Cheers

[South Africa]

Dear interested parties,

We tried to reproduce the GTAm tappet cover in England and found it very 'expensive' and probably cheaper to buy a secondhand one.

The aluminium one we made, as a one off, cost over £200. No machining yet. We then contacted a foundry casting magnesium for the historic/classic car market and they qouted about £2000 for a short run, less than ten, including 'casting tooling'.

The aluminium one in the photograph below is available. This could be welded and machined to suit the twinspark engine.

[Alex]

I know a good aluminium founder in England who does fine sand casting in gravity moulds. He's not expensive, either. Contact details are: Archway Brown (Non-Ferrous) Foundry, 43 Bury Mead Road, Hitchin, Herts. Telephone is 01462 432139, ask for Stephen Whelan. He has a very good pattern maker. How did you address the shrinkage issue?

Alex.

[maxmax]

Dear all,

I'm pleased to see interest for this topic.
It's encouraging to see that there's may be the possibility to cast a new cover.
I should mention though a couple of precision on the lasts posts.
1
Read carefully the thread. Although the title is GTAm cover, what we are looking here is a cover for the TWIN SPARK engine (alfa 75 engine) that LOOKS like the GTAm one. There are already (expensive) sources on the market for a copy of the old GTAm cover.
2
What I believe we are looking for is a CHEAP copy, not necessarily magnesium and so on (Carbon fiber?, Plastics?, Cheap aluminium?). We would paint in black or red or whatever afterwards if necessary.
3
A copy of the old GTAm cover do not fit on top of a twin spark. The starting point should be a 75 cover. We akwnoledge that the final result would be DISTINGUISHABLE from a real GTAm cover, but still BETTER than the 75 one.

Sorry for my English.

Cheers

Maxmax

[South Africa]

Dear Maxmax,

The differences between the GTAm and Alfa 75 TS tappet cover are fairly clear to me although I have not made any plans to manufacture one. In offering the GTAm 'reproduction' aluminium cover I was under the impression that an enthusiast would take one tappet cover from each engine, 'marry' them and 'make' one suitable for an Alfa 75 TS.

Dear Alex,

I am made to believe that the 'reproduction' GTAm tappet cover has taken into account shrinkage which takes place in casting aluminium. Let me discuss the process as explained to me.

An original GTAm tappet cover was used to cast an aluminium copy. The aluminium copy was cut into many pieces. Using the aluminium 'shrinkage figure' (if I remember correctly 1 in 70) and pattern making methods drawings were created, the many pieces bonded to some pattern making equipment and then welded. The resulting jigsaw puzzle was filled, filed and prepared so that the resulting casting from the pattern would look as close as possible to an original. Material was also added where machining work was to be carried out. Do you think £200 was a lot of money for the effort? Do you think the 'job' was professionally done?

[maxmax]

Dear South Africa,

I find this realisation excellent.
Why not investigating the cost of a finished "Old style" cover for the TS engine. May be if the final cost would be around £ 250 we could have a market out here. Certainly more than a true GTAm cover (I'd love to have a true GTAm head).

Cheers

Maxmax

[Alex]

South Africa,

It does look like an excellent piece of work, especially since that wouldn't be an easy item to cast. By way of comparison, this is a cam cover cast in magnesium by AlfaCar in Italy, although I've no idea as to the price. Probably very expensive!

To my mind, the smart way to make a master casting would be to 3D scan a TS cover and alter it in CAD to make it look more like a GTAm/'Piccolo' cover, then increase the dimensions by that shrinkage factor (from your figures, approximately 1.5%). The cover could then be 3D printed in plastic polymer to give you a perfect master copy, which would then be used to form the mould. But this would be a serious undertaking. That said, I've never liked the look of that modern cover in TS conversions and perhaps if you worked with one of the major parts vendors you could tap a whole new market.

Best of luck with everything

Alex.

[maxmax]

Why not using plastic polymers straight?
I'm under the impression that modern cars go for it.

Cheers

Maxmax

[Alex]

Injection mould costs would be horrific, I should imagine.

[jarrington]

One of the things that has kept me from pursuing a Twinspark conversion has been precisely this - the valve cover just looks wrong in a 105 engine bay. When I do finally take the Twinspark plunge I'd absolutely buy a classic looking valve cover, if available and reasonably priced (say, < $300 or so). Great idea.

-Jason

[maxmax]

Jason,

This is exactly my case. I look forward to finding a solution. My price range is similar. Hope we can find a solution.

Cheers

Maxmax

[South Africa]

Hello Alex,

Thank you for the link to AlfaCar. What a very interesting site. The magnesium tappet cover, for the 116 cars, is priced at approximately 772 Euro. In my opinion this is quite cheap.

The items they sell seem much cheaper than Furiani and OKP.

[PSk]

Just machine the grooves off the top of the twin-spark cam-cover ... only take 15 minutes in a mill. Bit of finishing work and it would look way more correct, if not perfect.

Lets face it, you've bastardised the car a little anyway, the twin-spark cover minus the grooves is close enough
Pete

[maxmax]

Quote:

Originally Posted by PSk Just machine the grooves off the top of the twin-spark cam-cover ... only take 15 minutes in a mill. Bit of finishing work and it would look way more correct, if not perfect. Lets face it, you've bastardised the car a little anyway, the twin-spark cover minus the grooves is close enough Pete