Car appreciation... the aesthetics, the engineering, etc

I'd buy a CAT D if I was going to track it with no qualms - it'd be a positive. I wouldn't touch a CAT C unless I saw it before it was repaired, and had full details of, and visibility into the process of, the repair. Which means it'd be vanishingly unlikely that I'd buy a CAT C.

I agree. A Cat D to use as a cheap run about or a track car would be the perfect use. For anything else, I'd spend a bit more money and find an honest car.

Cheers guys.

I do this kinda thing at work on occasion but we sub out to a metrology company and we tend to not use laser scanning for components, sometimes CT scanning, even so processing the data is arduous to process.

I’d wager I can cad up your lifter carriers with only a surface table and some verniers though for a shit load less money

Looks fast!

Challenge accepted!

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We’re you saying you wanted to get essentially the same thing re-machined in billet?

Those oil galleries could be challenging to replicate, you’d certainly be looking to CT scan rather than laser scan if you wanted to go that way

You really want these measured on a CMM, 3D scanning won't give enough detail unless you have an unbelievable 3d scanner.

What I can do for you is 3d print the finished part for a mock up.

My V70 had a brake bleed + new pads on top of its annual service today and on the way home the brakes were shit. I'll call them tomorrow and ask I suppose but is this to be expected? Like bedding in disc pads on a bike?

Very true, I think you need a model of the mating components to ensure a 3d milled version doesn't clash anywhere.

Yeah, I actually wonder if you’d be able to CNC it without changing the design, it looks like there’s a few internal cavities you might not get tool axis to

I'm happy for the design to be changed - indeed, that's the point.

They crack down the middle (very rarely) in normal use, my use is going to be abnormal though, with a smaller base-circle and therefore higher (and unsupported) lifters which need stabilising.

Oiling is a weakness that needs to be improved.

Surely the end goal is being able to sell the part to other Porsche people? Otherwise this sounds like a massive amount of work and expense.

One quote we've got back (from a guy who makes DFV parts) is £5,000, which is split between scanning and design (2k) and casting and machining (3k), for which we'd get five pairs of lifter carriers.

That's the minimum order, so we'd end up with a bunch of carriers that could be sold on - something that I've got zero interest in tbh, but potentially I could organise a group buy on the Porsche forum.

I do have a different route in mind, but it's somewhat nascent so I'll keep schtum on that one for now.

NA tuning for serious power and reliability is not a modest challenge either technically or financially!

Could you modify the existing part to reinforce it?

We can't get cam-blanks so, in order to get higher lift out of the stock ones we need to reduce the base circle, by 2-3mm depending on how the designer wants to cam the engine.

This means that the lifters (once pumped up) will ride 3mm higher, which means that they'll be inadequately supported by the existing casting - as the lobe presses the bucket down it'll exert a net-sideways load, leading to the bore of the carrier cracking.

So we need to build up the area of the carrier around the lifters - but we can't do it in such a way that we obstruct the cam lobe, which will retain it's current ultimate diameter.

I guess we could TIG material around the top of the bore, then machine back, but the oiling is also inadequate, and these carriers can crack along the centre line - so I think a clean-sheet is probably the most logical route to follow given all the challenges with the stock design.

The next question becomes what RPM can hydraulic lifters live with safely?

Cheaper to get billet cams than re-engineer that surely? Certainly to get the existing ones welded and reground.

Solid lifters are a pain - I'm guessing if you went that route, they'd be a bucket and shim type arrangement that will probably require removal of the cams every couple of thousand (enthusiastic) miles to set the lash.

Billet cams are what I’d term “proper expensive”*, and ones with decent lift would likely still crack the carriers.

/*Very sophisticated surface hardening required post grinding to get them to survive idling, something a racing engine doesn’t generally do much of.

Solid lifters- designer reckons 10k miles between cams out service.

10k is about the average superbike valve service interval, sounds doable. Might be different with a lot of track days, etc.

Looks a big project to re-engineer that carrier. Maybe bore out and sleeve them, then clearance the sleeves for the cam lobes?

I’ll update on which direction we take- if people are actually interested of course.

Boring car- V90 D4 R Design, 2k deposit then £245/month for 18 months, sound ok?

This exact car was delivered to my house yesterday on a 24 month deal. Lower deposit but slightly higher monthly.

Have a chat with Stoneacre Volvo in Sheffield.

It is a vast thing.

Why only 18 months?

Seems like a good monthly but £2k is a lot to put down if you're only leasing for a shirt period.

I ran hydro lifters on mine with a 264 duration cam i would rev that to about 7500rpm pretty consistently.

I had to go to solid lifters as soon as we went to wilder cams - I went 280 but i'd have needed them even with a 272, although i'm not sure if that's a function of the lift change

I also had to machine the lifter carrier, which is part of the head in my case, to clear the swing of the cam lobe.