new head stud installation quiery?

[Dan944t]

hi guys

As some may remember I have had to do a full engine rebuild on my 944 turbo due to a spilt bore, and I have finally managed to start and am 4.5 days in, however I have a couple of question one being I’m unsure the correct way to install new head studs?

in this I mean a couple of things:
the studs have two lengths of thread on iether ends as you will see from the photos added.
Now my questions are :

•do I lock tight the studs in?

•do I thread the shorter threaded end into the short block? Or do I thread the longer side down with enough length to secure my head with maybe 3+mm protruding ?

•do I bottom out thenturn back half turn ?

i have calculated with my gasket I’m using I will need 72mm stud + any extra length that will protrude above the torqued nut, so by installing the studs into the block with the shorter length of thread it would seem the right way to go as you will see from the photos this gives decent amount of excess length after the nut will have been torqued down. However the other way round with the longer length of stud screwed into the block is not long enough although if I bottom out and then turn back 3 revolutions as picture shows it give enough length on top as photo shows.

i was going to screw the longer end in . bottom out then back out touch and locktite with 542 but as this is my first full rebuild I wanted to ask some advise first to be in safe side.

many thanks
Daniel ??

https://imgur.com/a/PaTx4vm


https://imgur.com/a/3PKqSlJ


https://imgur.com/a/eOmMXa1

Ps I noticed also that the shorter threaded end is rounded at the top and the longer end is not finished so nice which would suggest that the short end shoukd be at the top but as you will see in the photos I installed the head with gasket and hand tightened , and you can see that the stud doesn’t quite make it through the nut, as serdi removes the old studs for me I didnt get to measure and look at the old ones.

 

[Waylander]

this might give you a pointer

https://youtu.be/4IFF_-6xwpE

http://www.cannell.co.uk/images/Cannell_web/944T%2048%208.jpg

 

[PSH]

Hi Daniel

1: yes

2: IIRC longer end in block...I didn't have this problem as Raceware studs have a different thread on the top for a stronger bolting force.

3: IIRC studs should protrude from block 73mm +/- 1mm (do check), I can't find my written notes to check...the Porsche manual isn't very well laid out, sometimes you have to hunt elsewhere for these things...

The studs don't go all the way to the bottom...... when torquing the head down put oil on the threads, be sure the studs don't move when tightening(this shouldn't be an issue if the loctite has been given enough time to cure)...I may have placed the head on the block as a visual guide during stud installation, alas I can't remember today but seem to recall something like that?

regards

Pete

 

[Dan944t]

this might give you a pointer

https://youtu.be/4IFF_-6xwpE

http://www.cannell.co.uk/images/Cannell_web/944T%2048%208.jpg

Cheers waylander, this picture has actually helped me out with locating a heat shield ??

 

[PSH]

Hi Daniel

I had a search through my build thread...this is the page that covers the head stud installation https://www.porscheclubgb.com/forum/tm.aspx?m=705721&mpage=7

A few points of interest, I used Loctite 577 pipe sealant to secure/seal the studs, also I note that I set the stud height at 75mm...I haven't said why... I suspect when checking with head and gasket in place that I wanted a little more thread for safety.

Pete

 

[Waylander]

This article says no loctite

https://newhillgarage.com...engine-rebuild-part-3/

 

[PSH]

This article says no loctite

https://newhillgarage.com...engine-rebuild-part-3/

what a random article states and what Porsche do themselves are two different things. Anyone who has removed 944 head studs will be well aware of the presence of loctite from the factory, quite a lot of it in fact, even in the said article it states to clean the threads, that's because they are full of loctite.

Pete

 

[Dan944t]

Hi Daniel

I had a search through my build thread...this is the page that covers the head stud installation https://www.porscheclubgb.com/forum/tm.aspx?m=705721&mpage=7

A few points of interest, I used Loctite 577 pipe sealant to secure/seal the studs, also I note that I set the stud height at 75mm...I haven't said why... I suspect when checking with head and gasket in place that I wanted a little more thread for safety.

Pete

Thanks pete,

funny enough i Had it in my head that I was going to set them at 75mm with my lock tite as you just said removing the old ones was a pig becuase of locktite so I got serdi to do them as they had to mill aWay my bores anyway. Funny enough John actually said not to put locktite on but I am going with what I believe I should do and as porsche did it I would feel more at ease locking it at a hieght I need as they are very wobly unless you bottom out on them so the locktite will firm them up and make them secure, I sure do t want any movement.

Im at a bit of a standstill waiting on stem seals from porsche as Euro carparts said they can get me victor Reinz seals for today so I took a break from main dealer prices and waiting times ?? for these as everything else to build the engine minus the big end glyco bearings are from porsche....... but wen I got there today they gave me a parcel that contained 8 , 911 manifold gaskets!??????? So I wasn’t a happy bunny as I had planned to get the engine all built up this weekend and ready to go into the car.

So so I ended up ordering from main dealer for originals and have to wait till Monday to build up the head valves ect.

thanks waylander also

??????

 

[Waylander]

I did think it was a bit odd, especially as the holes are a lot deeper than needed

Manuals If needed
https://porsche968.s3.eu-west-2.amazonaws.com/944/Vol1x-engine.pdf
https://porsche968.s3.eu-west-2.amazonaws.com/944/Vol1Ax-Engine.pdf

 

[blade7]

The head studs that I pulled from my 2.7 engine definitely had threadlock in the block, I'd have check them but I think there is a different pitch thread on opposite ends of the stud.

 

[Waylander]

if you want stuff from Euros, let me know, my son works there

 

[PSH]

Do check the heights...I think that I had to go higher due to the Raceware washers, IIRC they are much thicker than standard. Yes, the studs are a little wobbly when dry, I think ARP state to use something like PTFE tape, I can't recall what Raceware said. Porsche do things for a reason and there's no denying that there's an awful lot of Loctite used on the factory fitted studs....

 

[Dan944t]

All threads degreaser , hoovered put and 75mm height gig made ready for new studs to be locktite into block.

i guess I’ll just have to put the turbo back together with the rebuikd kit. Forgot to say pete that I found a company that has a good track record and would balance by turbo shaft ect with printout along with the rebuild kit.

When i spoke to them on the phone they knew the k26 turbo very well which put me at ease and as I said before I would rather build the turbo myself it was just the balancing of the internals that I wasn’t going to scrimp on, so I was just about to send the whole turbo off to turbotechniques until a friend told me about thus company that he used many years ago when he had his own tunning company, so I niw have my turbo inards back with spec sheet for the balancing and all parts checked out good with very little wear, and the blades look like new as they had to clean them up to inspect properly. All in £76 with postage so I’m very happy to finally save a bit on this build and at least I know I will have rebuilt it myself, just have to line up the appropriate balancing marks they did for me.

this way it keeps me from upgrading any further for a few years yet, unless I win the lottery that is ??

atb
Daniel

 

[PSH]

interesting Daniel...sounds good...here's to the car being up and running soon...