550 Spyder "4 cam"-like engine build up **NEW UPDA

[sled]

Turk Turk, updates?

anyone updates on their projects?
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drive your split.

[M-Owen]

Well it's a very impressive oil pump non the less!

[gears]

Well, that's only half of the components for a 4-cam pump. It was made by my machinist, who made two when he was presented with the job years ago. Although it's been judged to be of higher quality than the other German-made replacement pump for these engines, the close-knit politics of 4-cam restoration has delegated this one to my display case.

[M-Owen]

[M-Owen]

Here is a picture of my first mock-up, Now that I understand how to post pictures I will take some better images and post when machining is completed.

And yes you were right it wasn't rocket science just a different procedure from other forums. Look forward to your feedback.

[M-Owen]

To make matters worse I am an engineer with a PHD you would think I could figure out how to post a picture in a forum. I will sit down this weekend and overthink the picture posting thing

Very nice oilpump

[gears]

I can't make any atomic weapons, but I might be able to insert a photo ..

[miniman82]

[M-Owen]

Turk have you gotten any further? I have most of my engine mocked up and I did decide to reconfigure my drive system but still stayed from convential wisdom, I am using the original cam to drive porsche cams at an 1:1 ratio (opposed to driving from crank) now I designing the oilpump that will fit in the void left from back half of camshaft.... as usual when i figure out how to post pictures I will do so soon!

[micheloaks]

c'mon post a pic!

[M-Owen]

Hey Michel I have not gotten a chance to take any pics of my work on the engine yet and I sure Turk will tell you that I have been promising for sometime now. I did send my case to the machine shop yesterday thanks to my son and with some luck I will pick up my camshafts when I get home and get them assembled so that can be done. I am also experimenting with some the high strength epoxy's for joining my cam towers as opposed to the stress associated with welding stay tuned...

I saw those heads being developed by 5speed and I must admit I am envious and a little sceptical of using 4 valve heads on aircooled heads I keep thinking about heat build-up They would be great as a high revving 2valve design... maybe I should stick to designing heat pumps not cylinder heads

[micheloaks]

turk turk its been said before but...amazing and tenacious! looking forward for more posts and development pics.

Mark have you had any success with machining parts and any pics to post?

Of interest look at Martin Bott's project at [email protected] A contemporary iteration of the 4 cammer. I believe all new excepting the use of Porsche cylinders

[M-Owen]

That looks like it will work. What did you decide to do about oiling?

[TurkTurk]

I appreciate the compliments, here are a few pictures of my newly designed camshaft retainer. Im having the cylinder spacers machined this weekend, I'll post pictures of having those machined and inserted/bonded in. One of the retainers is "cleared" to see the spring-lifter assembly. A design choice that I made was the split the two retainers. I did this for a specific reason and it relates to an engineering concept known as constrain-theory. It is obvious that under-constraining a component means that it will move where ever it wants under load. For instance, if your crankshaft only had one half of the crankcase to sit in, it would be under constrained and would simply fall out of the case. Just as poor a design is known as over-constrained. This is when too many constraints are put on a component and two many variables effect accuracy of alignment ect. If I had designed the retainers as one unit that held both lifters and both camshafts, the accuracy and precision of the lifter bores would be affected by the forces on the camshaft and vice versa. By separating the whole assembly into four distinct units, the precision of the lifter bore is not affected by the camshaft and the camshaft concentric to its bearing wont be dependent on extenuating forces of the lifter,springs, expansion, bolts ect. Because the camshaft and gear assembly isnt connected to the lifter, neither should their mountings. However, the parts will have several "alignment" slots or pins that keep them true in relation to each other, they just wont be a singular piece. So, the camshafts and gears will be a single unit on each head and each lifter-retainer pair will be one unit, the two bolted together on the cylinder heads.

[Stuggi]

This is just insane, just the hobby I want to be doing after my engineering exam (I'm enrolled onto Finlands best mechanical engineer program). Keep up the good work!
_________________
1970 Beetle
1969 Panelvan

Orange VW Fest!
Pulled out of a Lake Fest!

[M-Owen]

If I haven't told you how impessive your project is ...

[TurkTurk]

An update to the project:

I've acquired more engine components. My first major priority is to mock up the short-block minus the layshaft and internal bevel gears. I beleive I've finally settled on the supplier for the spiral bevel gears, its hard to come by a company that keeps the correct size in stock. I've purchased a set of really nice stock length (5.000) in. Pauter connecting rods from Jake. Those will be sent promptly to Pauter to be re-bushed for use with 85mm JE 911 pistons that are set up to run 10:1, perfect for dual plug.
On an interesting note, I've decided to use Hydraulic tappets from a Ford 4L DOHC cam engine. I've done a basic mock-up of it below. I'm doing this for several reasons: the hydraulic lifter will allow me to design for zero tolerance between the lifter and cam. It makes things simpler when designing the cylinder head camshaft retainers. Furthermore, and more importantly, the camshafts will not be asymmetrical and wont have to have those funny flywheels on their ends.

What is an asymmetric cam and why did Porsche use them? An asymmetric cam, as described below in Porsche's own literature ( a Carrera Engine manual), is a camshaft where the shape of intake curve is not the same as the shape of the exhaust curve, they are "asymmetrical". This was specifically employed because of the use of theactuators used between the valve and cam lobe. As you can see, and as it is described in the manual, the cam lobe does not run on a constant surface relative to the lobe surface and therefore the timing must be different for each part of the cycle. This isnt' an issue on flat-tappet systems like those seen on most cars because the cam lobe is faced with a flat and therefore constant-curved surface throughout a full rotation. Anyway, using a hydraulic lifter does away with that and all I have to worry about is getting oil too it, which is already a design parameter stimulated by camshafts,bearings, and gears in the head.

Lastly, I was reading some literature on the Porsche 959's engine today. The 959 engine used an aircooled block and cylinders and watercooled heads so that 4-valves per cylinder could be employed (the whole reason for watercooling in the 996-forward 911 iterations). That got me thinking how cool it would be to use a 993 block with 996 heads, twin kk turbos, ect to create a "replica 959 engine" in the same spirit as this one. Anyone want to see THAT tackled after this? Interesting note: the 996 turbo/GT3/GT2 actually use a similar configuration. Their internals are essentially 993 items with water-cooled cylinder jackets and 996 watercooled heads. Once I get a little time off this upcoming holiday, I'll be able to start posting pictures of hardware mock-up. That's when it will get exciting.

[TurkTurk]

Yeah, that's what I was planning on doing, running an An line through a pushrod tube into the cylinder head. Not only will this protect the line, but it'll look more "factory" and less "race-car". Also, Im currently working on getting data for the buck I'll be building for the aluminum body. A fellow here in Atlanta has original body panels form a 550 (most important being the rear clam shell) as well as fiberglass molds from an original car. I'll use a contour gauge and a hell of a lot of time to build an accurate buck from which to make the body. Bought another Carrera assembly manual, this one being more detailed with lots of info on bearings retainers, checking and adjusting backlash ect. Moving along..

[Jake Raby]

I'd feed the oil via a -4 AN hose from the main oil galley... I do this on my engines in some instances.
_________________
Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

[M-Owen]

Hey Turk,

I am pretty sure the cams on the furman engine recieved their oil via internal ports. If you are still using 911 heads with a custom cam towers you might want to consider external oiling like porsche did with the 908.