Carpokes Porsche Forum

My block has been prepped with Timeserts for Milledge/Heritage 9/16" studs, but since getting the block and studs, I also got a set of ARP Custom Age 625+ 9/16" studs through Gustaf/Duke's efforts, and got them in a custom size to the exact height I need. I'm sure either set is a massive upgrade over factory/raceware etc., but I have no real basis to decide between the Milledge/Heritage and the ARP set. Milledge is a proven commodity, but ARP Custom Age 625+ has impressive specs and is used in plenty of other high output motors. Anyone have insights?
Left to right: ARP 625+, Milledge, and standard size Raceware for comparison. The Milledge washers are the best of the bunch at 5mm thick. The ARP washers seem cheap in comparison -- seem to be stamped, with sharp edges and only 3mm thick. The ARP studs to have a nice hex socket on top for ease of installation and removal. The shank of the Milledge studs are about 12.2mm, while the ARPs are about 11.9mm.



Hard to capture the difference in size in a picture, but the 9/16" studs look huge next to the standard size.

I'd talk to Eric. We should get him on here as his input is always worth taking note of on anything 944

It's only my opinion but I believe a deck plate makes bigger head studs redundant.

Eric is a member here, but he's shy.


Thom -- do you have pictures of your decked block?? Please post!

Here you go. The block was slightly skimmed after the install and the pistons designed accordingly. I have run the engine up to 1.5 bar of boost so far and it didn't break a sweat.

Thom wrote: Mon Jul 12, 2021 12:33 am Here you go. The block was slightly skimmed after the install and the pistons designed accordingly. I have run the engine up to 1.5 bar of boost so far and it didn't break a sweat.


DSC_0250.JPG

Holy cow that looks good. Who did that work? Is it welded in or press fit? Any special efforts to cool the top part of the cylinders? How are the coolant temps?

The company is ETG in Germany. I did not ask about the process but I believe the deck plate was pressed-in then welded then skimmed. Coolant temp is slightly higher but not by much.

Thom wrote: Mon Jul 12, 2021 12:15 pm The company is ETG in Germany. I did not ask about the process but I believe the deck plate was pressed-in then welded then skimmed. Coolant temp is slightly higher but not by much.

Did you add the steam vent line at the back of the head? I did it on mine and it does seem to help -- if nothing else, venting the coolant is a lot easier... I'm also a believer in Water Wetter -- it's good for a nearly needle width on the gauge in my car...

I believe it will run a little cooler when I will install back the extra oil cooler. Clearances are tight on an engine with all new bearings/rings so I wanted to break the engine in running on the stock oil cooler only which as you know is ultimately way too small for a 3L engine.

S2/968 heads have the steam vent line from new.

9/16 head studs in my opinion are worth the effort in a highly modified motor, always should
Be used in conjunction with a multi layer aftermarket gasket. When plans of a sustained high boost/long pull engine is under way for a high power application like most of the users plan a m doing here well they have less stretch, less movement laterally as well. Bottom line is the head stays put Right where it should up until the next weak link in your build arises. Money well spent however which ones to use when options exist??? I would go with your gut on this one as having them in your hand to compare and being able to make a decision on real visual fit & quality and the numbers presented to you is going to be your best bet so that your happy. I would go with the one that didn’t have to be re torqued after break in every time of it existed ha ha I hate having to take the 2 cams out to re check everything…..