Wormhole

Milledge used Heritages studs, thay are being install into my block at the moment. Along with some other goodies of course.

Duke

Sorry my bad. Milledge warned me of the generic ARP 9/16 studs as he was not aware ARP 9/16 studs designed by PD.

Duke

IIRC you had a 2.7 or 2.8l 16v turbo engine, is this another engine or is your engine apart?

JohnKoaWood

New engine? Or rebuild of the CW engine?

Wormhole

The engine was built by me, not Chris, although I did use his duel cam gear setup. Same block, but needed to make a few changes.
Duke, it was a 2.7L

BC

Blown - Is this still E85?

You should essentially not be seeing ANY detonation at all. Possibly you could see some pre-ignition due to hot spots like the plugs, (ethanol will not like hot spots) but thats about it. Even with 21psi of boost and 11:1 compression, with the proper timing control you should be able to have a controlled burn environment.

The heads need to be clamped down with fasteners that are IN tension at final position. This is the problem, as I understand, with many different aftermarket studs.

I have a very good friend, with a very similar engine. 29psi and 600 at the wheels with no head lifting of any sort. And this was on pump gas - not the awesomeness that is ethanol. Massive amounts of methanol were being injected, but....

Remember that if there is any uncontrolled burn that the cylinder could be seeing 10 times as much peak pressure as normal.

With additional compression, the normally-advanced timing may need to be dialed back just a bit.

blown 944

Yes still e85. The winter blend which I have measured to be closer to 80% ethanol.

I have been trying to monitor knock events and I havnt been seeing many. I'm going to hook up my egt meter in a few minutes and go make some runs for measurement. Just to be sure that I am not frying the exhaust valves. I dialed my timing back even further last night with the fqs, so I am at very low timing at peak tq around 16 degrees iirc. I'd have to look at the timing maps to be sure but I'm pretty sure that's about where it is.

At this point though, since I have found a couple nuts out of tq spec I'm leaning toward studs or threads. I'll be pulling the head in the next couple days and I'll be able to confirm wheree I'm loosing pressure.

Good point about the hot spots, I may try some colder plugs for the next test.

Thanks for the input.

blown 944

Ok so I'm about to order new studs. For those using the larger diameter studs, what modification must be done to the head? Also, is this a task that could be done in chassis if the engine were slid forward? I can fixture a drill press to the deck and tap the threads I think. Ideas??

If it can't be done then I'm going to just get the race ware from Lindsey since they seem to be the least expensive. I don't feel like getting carried away with this engine since it was a temporary test anyway.

blown 944

what about ARP? these are only $180 and rated at 200,000 psi

http://arp-bolts.com/images/releases/pdfs/204-4211.pdf

edit: doesn't matter now, I ordered them through Jegs. They price matched at $148

DLS

Dammit i just got my arp studs and i payed $175+ shipping
you got a good deal

Duke

The stud channels on my 968 head had to be drilled out.

blown 944

Thanks Duke. I'll have to look into these studs for my 16v engine. The stud length is different on the s head iirc.

For this one though, cheap arp studs it is. I hear that they can be torqued to 100#ft so that's what I'm going to do.


So the plan is

Arp's at 100#'s
O-rings protruding .015
Widefire

Anyone see a problem or recommendation?

audisport

There is some good info in this thread from my recent ordeal. Measurements, drilling ect.

https://rennlist.com/forums/944-turb...nt-torque.html

blown 944

Thanks for the link. Definately some good info in there. Glad to see you got it sorted out. I'm hoping I see clean threads when I pull them out though :-)

User 52121

I love techie threads like this. Nothing to add - just subscribing Though for the record - I see nothing wrong with looking at "lessons learned" from other marques (like the Evo guys.) Yes, entirely different motor... but when entering somewhat uncharted waters here, where else are you going to get ideas from? The sky?

Good luck Sid!