Hi All -
I have been watching the usual places for a set of weber intakes for my conversion. I need the 36mm ports on the engine side (2.7l). Everything I find are 32mm. Are the 36's rare? I know I have read about some having the smaller ones machined, but at that point, wont the cost be similar to just buying some PMO's?

Would love your thoughts - thanks.
Scott S

Port matching can be done with a Dumor (die grinder).

If you are thinking about enlarging the entire manifold that would be another story, but it has been done with the same tool. Only problems are having a spare one you can cut cross section to see how much metal you have to work with and maintaining equal thickness around the bore.

Pretty damn rare. AFAIK, those manifolds came only on the 67-68 911S.
The 32s are easy to port out, tho, as Slits said. I did some then didn't use them. They are magnesium and it goes quickly.

Hi Scott,

This may be the same part that is in my car from the 68s engine. I cleaned my set up and glass bead blasted them. I found this ad with the part number on Google. A set had sold on the bird board for $175 not to far back.

Bob

Porsche 911 Vergaser Ansaugbrücke, Saugrohr 40 mm

Ebay ITEM # 370092724476

Nähe Paderborn, Deutschland
Versand nach: Deutschland

http://cgi.ebay.de/Porsche-911-Vergaser-An...=item562b3ed0fc

Scott,

OLD POST My part number is 901.108.321.OR it was from an early S on my 2.5 68S

The size is 41mm over 38mm on a low dollar bullet loading plastic gauge.

36mm 2.7 ports have an notch for the injector, PMO manifolds are shaped to cover the divet in an otherwise round 36mm port.
If you use early manifolds be sure to at least get the PMO black plastic spacers and gaskets for the 2.7 S port to prevent an air leak.

stole some pics from the bird

I's not hard to match port the manifolds to 36mm. I did a set recently, it took me a couple hours. The biggest mistake one could make is to try to enlarge the whole thing. If you just match port it you'll be OK and not ruin the flow. You must maintain a smooth shape but don't polish them, not that kind of smooth. I think the experts say to finish with 80 grit but magnesium is soft so I finish it with 100 or 120 to have scratches on the sides similar to 80 grit on aluminum.

Which is why I didn't use the 32s.

I'm told that using just the plastic insulator doesn't always work out well.

true but its worse without them.

I spoke to PMO yesterday - they were very helpful (even gave me jet reccommendations for our crazy altitude). I would rather be safe that sorry - I have heard of the air leak problem - so I will be using their manifolds with the insulators. While the more expensive, it is way less expensive than doing it twice. That I cant afford.

Thanks All -
Scott S

just for the record;
greasy factory manifold -Left
semi clean 2.7 head- Right

I hear/see you, but.....
6 chances for a vacuum leak, whether when you first fire it up or a few years later, doesn't fit in my play book. Getting the tune right is enough of a stinker (particularly for a first timer....BTDT). Who needs that possibility in the works?

We are in agreement, who are you arguing with ? I am showing the air leak.




JP you dont even own a 914

I am not at work where the fresh 76 2.7 S heads are. I will take a picture of them on Monday and post it so you can look over my now fresh glass beaded intakes and please give me advance advice on the fit.

Bob

youre in the same boat as the greasy parts. pmo is the best way to go,
plus they are a bit taller.or they make a tall manifold
Or
take a chance with the plastic spacers
Or
have the divets welded up making a round port so you can use your early S manifolds.

True, but when I did, it ran....well, every summer.
When is that GT gonna come out of the closet?