Porsche Enthusiasts Club Forum

Don’t think I will risk that Rob

Then you need this:

Not quite readers wives is it

Nope.

Or Razzle.

She was quite interested in the result, don't know why.
Just exhaust port, inlet not set. Nice shape but you can see the rough spots. Fun to do, a begger to get out I used a silicone spray to help separation

You can buy those off the shelf in Amsterdam

^ In the context of what I posted...

@Endoman: When you say 'playing with an S2 head', is this for spares or will it go on your vehicle?

Have you read up on David Vizard's 3000 page manual on porting?

I will be pulling the engine this summer and I'm intending to use this head after a bit more work so the old head will be spare.
Yep I've got Dave Visards book even his '85 book on A series and cut outs of the B series published by Car and Car conversions. There's a good one by Peter Burgess. D.V. doesn't cover 4 valve heads to any great detail but there is a thread on Rennlist concerning the 928 which is very interesting. I've worked on B series heads and the MGA Twin _Cam head. Interestingly we got 135 bhp from both @ around 1600cc. with better torque from the pushrod engine. The pushrod engine was highly modified but modification to the Twin_cam was very restricted as it was already pulling 110 bhp as standard and bigger valves, more radical cams just killed the midrange. Best mods were 2x42 DCOES (rocking horse droppings as thay were original fitment to a 6 cylinder Maserati) and a one off exhaust made by a mate who was ex Chevron. It seems like 1 step away from steam driven looking back, no ecu, no injection, no or very basic electronic ignition (which was crap)
From my moulds the ports look really well designed and constructed so I won't be gouging junks out just smoothing to leave a satin, not polished surface on the inlets, The exhausts I'll get as shiney as I can.

I had my GT250 in the kitchen when my old man went on holiday, My Fireblade in the front room of a cottage we used to rent. And my brand new S1000RR in the dining room until I made space for it in the garage. Her indoors has said no more bikes in any house.

I wonder why she said that, it’s a bit unfair when you pay the mortgage or whatever

As to the ports I have read some posts from RSBarn that basically say that if you could make the ports a bit smaller on the 968 head you would get more power at high revs as the gas speed would be much higher

But I am just a dabbler at the edges of big engines, but did make expansion chamber exhausts for 2 strokes back in the late 70’s early 80’s

(Although the 3000 page reference to DV wasn't serious).

I met DV in Croydon eons ago when my friend and I picked up a 1700 x flow for a Dutton which to date, was one of the quickest vehicles I have been in. I'm sure in my faint recollection, it was fitted twin DCOE 45's.

When I partially rebuilt a 2.7 engine for my 944, I did a silly thing and broke the cam.
I looked at Woolies who supply a high lift cams from a supplier in Gloucestershire.
I wanted a replacement but not a high lift, just original pattern.
Quite inexpensive really and required a slight alteration of the ECU. 25 bhp more in a n/a engine. I talked to the supplier and he tried to tempt me but I declined, being a bit of a purist - you either restore it in original condition or fully prepare it for track. Thankfully, he found a 2.7 cam for my engine in vgc.

Anyway, to cut this long story shorter, he said something interesting: He said 'In the 944, they never really got the overlap right'.

(Haven't fitted the engine yet, as i'm building a garage with a ramp - woohoo, so i'll wait. The planning dept. can bloody well hurry up).

Tempted with higher lift cams for that head?

Been a while and lots has gone on that I haven’t had the opportunity to write up. Special thanks must go to Waylander for his continued support but also for some physical help with another as yet unwritten significant step.
Anyway, enough of the excuse today’s ( actually it was yesterday) milestone was.............

wait for it..........



Drum roll please...........




replacement of the lower radiator mounting rubbers!

More was planned but as usual life got in the way and that was all I got time for.

Sorry.

I’ll go back to my cave now.

Paid off the mortgage years ago. It may have been my plan to have a Ducati 1198 as an ornament in the house. When I was an apprentice I made some stainless expansion chambers for the GT250, stingers with no silencing , it sounded really fast.

Like most sports exhausts all noise for no real benefit

They were actually faster at the top end, but I think they needed better porting and carbs to really work. Proper pattern development on the cone sections, and I copied the lengths of some genuine race pipes. When I went on to bigger and better strokers I sold the expansion chambers, and they got used on a couple of different RD Yams.