Red rooster

To resolve this does anyone have the compression height , pin centre to piston crown ,of N/A and turbo pistons ? If the height is the same , they fit !
Back to the experts .

Geoff

Kevin

Don't you see the step in the 993TT cylinder head?? The 993TT piston protrudes out of the linder and into the cylinder head. Your info is incorrect.. Out of the box, if you install 993TT pistons and liners with NA heads you will have issues!!

And how did you install 964 rods which are 930 rods in to the smaller 993TT piston pin boss? You can do it with a custom rod.. Post a picture of your pistons.. I bet you used 964 crank, 930 style rods, 964 twin plug heads AND pistons and liners from a '94 3.6ltr turbo. That combination would work.. But it isn't a 993TT combination. Like I said post the pistons and we will see what you actually ran.

Rickard 993 Turbo

I know Micke Svens alot but if you don't se the obvius i give up, you have alot to learn about the 993 engien it's not like the stoneage 930 things you know a little about..

Rickard 993 Turbo

Beepbeep=

beepbeep

Engine used GT3 Cup crank, 964 N/A jugs, 964 N/A heads, 993TT pistons and custom Autoverdi steel H-beam rods.

We are still investigating this, but if you are right then 993 pistons either have longer distance between wristpin center and top of the piston (thus allowing it to go into the head) or rods are longer than for N/A version? This might be adressed by using custom (shorter?) rods in this motor.

Are you saying that 993tt and 9933 N/A liners are of equal length and that whole piston top portrudes more into the head than on N/A version? Beacuse if 993tt liners were indeed shorter then N/A ones (which is information I got), then piston would portrude past the edge on 993tt engine with 993tt jugs but not on N/A one.

beepbeep

Yes, Rickard. You know all about everything. We already know that. Now please give up. Let me do my stoneage things I know little about.

Rickard 993 Turbo

You seams to have missed the yoke

But why can't you listen to when they tell you how things are, Kevin know for 100% how it is so listen to him, geoff also...

I do not know everything but im trying to listen when the experts are talking and they know alot more on this then i do...I know my Japs turbo **** but here i have alot to learn

Im mean that for like 2 weeks ago you didn't know that the 993tt engien was a singel plug engien for example

Rickard 993 Turbo

can someone explain the diffrent between them

Kevin

In all fairness to a talented machine shop anything is possible.. The 993TT cylinder is 5.34mm shorter than the 993NA cylinder liner. The 993TT cylinder makes up for the depth/height.. This is important for the camshaft/chain housing alignment. One thing that you should remember, the reason why Porsche used the 993TT cylinder head and liner design was to take slot of the combustion pressure/stress away from the cylinder head/cylinder sealing ring/surface area. The benifits of having the piston in the head does have merit in a high output HP engine when you start to use alot of boost.

Again with enough time and money one can make anything work. If the NA heads were machined to get the correct deck height and you started to change the rod lengths things could work.. If you have all your parts lay them out on a bench and take a picture of the crank-rods-pistons and heads..

Years ago I heard that someone wanted a lower displacement turbo engine but wanted to use the 3.6 platform. They used a 930 crankshaft to de-stroke the engine. They did use the 993TT pistons to keep the compression ratio up vs using the late 965 pistons.. It would be interesting to see/find out what the compression ratio is/was of you engine setup. Ruf in years past would use 964 NA pistons and cut them down and install in there early 3.6 turbo engines.. I'd hate to see someone cutting down a set of 993TT pistons to make them work in NA heads..

Geoffrey

I think you mean to say that the 993tt cylinder head makes up the 5.34mm difference so the cams and camboxes align properly.

beepbeep

Yes, that was what I was trying to say all the time! Cylinders are shorter but heads are deeper. But you must remember that we are planning to use N/A cylinders with N/A heads. Everything is N/A except pistons. So when installed in 993 N/A engine with N/A cylinders, 993TT pistons won't portrude from cylinder edge anymore!

Yes, I'm totally aware that sealing won't be as bullet-proof as on turbo heads, where combustion is partially moved into head recess but that's a gambe that we are willing to take. Old engine which used 964 N/A cylinders and heads with flamerings actually never had problems with sealing, not even @ 2 bar of boost...believe it or not!

Yupp. We are totaly aware of this fact. Unfortunately, 993TT engines hhave significant price premium compared to N/A ones, so right now it seems that it's a bet Jocke (owner of the car) is willing to take.

It remains to be seen. I never worked wioth 993 engine but there are reasons to believe that deck height issue will take care of itself as N/A cylinders are longer and will thus achieve same deck-height.

beepbeep

Rickard, I find your recent posts quite arrogant. I posted this thread to gain more information about 993 engines and not to read what you think of my engine knowledge. :-|

As you can se in Kevin's last post, N/A cylinders indeed are 5,34mm shorter and that 993TT pistons thus won't portrude from the edge anymore when fitted in 993 N/A engine. So issue of 993TT pistons hitting combustion chamber roof when mounted in 993 N/A engine with 993 N/A pistons and 993 N/A heads just beacuse you saw a picture of them portruding the edge on 993TT turbo engine isn't resolved yet.

Rickard 993 Turbo

You shouldn´t it´s standard internet trach talking..

red993tt

Here's what you need......

Rickard 993 Turbo

I understand what you mena but the qestion was if the 993tt pistons was protruning in the 993tt head and it does, all years...

That was what we first talked about and what i mean tthat we are sure of, and wha tmy pictures are showing