Michael D'Silva

hmmm... not sure I totally follow this but I have my motor apart and currently I am at the stage of installing the intake stacks.
I bought the 993 part numbers and noticed the differences in how the injectors sit.. I have not bolted the fuel rails on yet to see if there is a problem.
But seeing as there is comment from the experts about power loss at higher rpm due to different sized outlets, I think I MAY go back to my 964 parts.
Here are some pics comparing how the injectors sit in the stacks... 3 photos of 964, then 3 photos of 993

ras62

The fuel rail mounts fine and the clips holding the injectors also mount fine. There is no problem with the injector sitting a couple of mm higher.
As for the performance issue I dont see it and certainly my engine runs better. There is near perfect alignment between the inlet port and the stack...put them in place and take a look.

Mezger

Rocket Rob

They are M6 studs, so I torqued mine to 7 ft-lbs

kevin2012

Sorry to bring this old one back.
May I ask if it supposes to have "pop" when installing the injectors into the stacks?
How much force will be needed?
The reason why I ask is that I recently cleaned and reinstalled the injectors back to the stacks, now the car seems to be running lean. When I reinstalled the injector back, it was very easy without any need of force at all with all new o-rings. The injectors could move quite freely before putting the fuel rails. Is that correct?
Mine is a 1995 993.
Thank you.

JasonAndreas

Yes, there is "pop". Where did you buy your o-rings from?

kevin2012

I bought the o-rings from Design911UK. I had compared them with the old one when installing them, they look exactly the same.
Thanks.

Vandit

I think it's been 7+ yrs since I did this job and I don't recall the feedback of the injector going into place, however I do recall I used a bit of ATF (automatic transmission fluid) on the o-rings as a lubricant during installation.

kevin2012

Thanks for the reply.
in my case, no lubricant was needed as it was not tight at at.
The part number of the o rings is 94411090101.

Vandit

I had the injectors serviced by WitchHunter Performance so they came back to me with fresh O-rings that I didn't have to source.

Goughary

If you didn't take the stacks off to clean- or even if maybe you did- you have to remember that the type of gook and grit in there is hard and black....and usually for most people it's still in there after cleaning- because it's hard to see and hard to get out.

So there is that. Maybe something filled in the slot for the o-ring....

And then- another thing to remember, is they are plastic and when old, they are brittle- so make sure the loose one isn't broken or cracked (which is kind of like saying "broken or broken...lol)

But yes- they should snap in. If they didn't - and they are loose- you will likely leak. So be careful. You don't need an engine fire.

titleistaddict87

If anyone is interested in 6 brand new 993 intake stacks, pm me. Just finished my engine build and decided to stick to my stock 964 stacks as they were in great shape. I also have the 6 seals needed but will need to double check. All purchased new from Porsche Marin and test fit only.

Gregg-K

This thread is pretty old, but when I tried PM'ing you, I found your inbox is full. Do you still have those 993 intake stacks for sale?
If not, maybe someone else has some?
Thanks,
... Gregg

Gregg-K

Looks like titleistaddict187 no longer has inlet stacks for sale, so I'm still in need of a set.
Anyone out there have a set of inlet manifold stacks they would sell?
Thanks,
.. Gregg