Vilhuer

Please do. I think I have measurements for how deep block is, how much there is thread, how thick both type heads are etc. I'm also interested for well made set for late style heads.

BC

Well, I need another set too. And I could sell this set easily if we can organize someone to make some studs in the design that Mike has thought up if its needed.

Mike - the stepped area - is this not an issue in stress rising? The rod bolts that do this do it in a gradual curve, no?

sharky47

Some one PM me with actual dimensions and I will get on it!

BC

I am in Chicago now, I can't email the 89+ dimensions for the studs until next week. Anyone else?

Mike Simard

I have dimensions for head and main studs to share if anyone wants to make some, Sharkey', I sent you a pm, do you want to make some? Everyone building a serious engine should have 'em but given that only a handful were interested in ATI dampers, nobody's going to retire making 928 fasteners.
I have several sets in process right now, here's a pic of some. They have a hex milled on one end for convenience, next step is to heat treat them then finish turn them. I'll then send them out to have the threads rolled and a zinc chromate finish. I will have to farm out the thread rolling so please let me know if you can help with that Sharkey.
Some will have to be sacrificed in testing to determine limits and clamping procedure. This does seem like a huge amount of work, like building a house and taking the time to make nails but I feel that it's very important to engine durability and IMHO critical fastener design is often ignored by even very smart engine builders.
BTW, I'm making the head studs for the longer 89 design and will use a spacer for earlier heads. The mains are intended to be used with a girdle (another story) so they are a wee bit longer, with the hex they might need to be trimmed if used with a stock un-spaced oil pan or maybe not.
Brendan, the idea of the necked down body is to provide material for stretching. That allows the stud to be tightened to a point below yield and not permanatly deform if (when) hammered by detonation. Otherwise the minor diameter of the exposed threads that aren't in the block or nut are the only places that allow deformation. Even a very short distance of the body reduced to slightly smaller than the thread minor diameter would be very helpful. Mine aren't going to be reduced the whole distance but will look like worms that swallowed peas. It would be convenient if the 2 shorter head studs had the same amount of stretching as the 18 longer ones so that they could use the same tightening procedure.

Vilhuer

If price do not go up to stratosphere I'm interested in sets of both '89+ head and main studs. Some mm longer mains are ok as I'm adding spacer between block and oilpan.

fst951

You guys really may want to do a little more research before trying to make your own studs. I think that it may require a little more engineering than you think. I assume you are using 4340 for 8740 Cr alloyed steel. There is NO way that you will be able to roll your own threads. Cut threads are going to fail. Tapering is fine and allows better stretch, but also realize that the heads studs used in 944s tend to be non-tapered and last a lot of years!

Really nice looking project, Mike.

Mike Simard

Whew! After waiting for studs the block can finally be clamped together and sent away for finish honing . Here they are, studs designed for proper clamping and heat treated properly with threads rolled in the hard condition. they even have little hexes milled on the ends for assembly. I made them long enough to be used with the girdle/spacer I'm making. I still have to wait for the results of pull testing of the sacrificial ones in order to establish clamping procedure but it feels great to finally get these things done.

BC

Cool. After testing is proven, will you be selling them?

90 S-4

Beautiful work, that motor should run strong and smooth for many many year's -- Good Job !!

Mike Simard

Brendan, I have 2 head sets and 4 main sets. I didn't think anyone would be interested but I could sell a couple of main sets at least, maybe the girdle too I guess. It would be big money thou


Joe, thanks! We'll see how long it lasts . Building 928 stuff is like a Calvin and Hobbes where Calvin asks his dad how they know the maximum truck weight for those bridge signs. His dad said they drive bigger and bigger trucks over it until it breaks, then they rebuild the bridge and weigh the last truck.

Mike Simard

The spacer is 3/8" thick. I'm going to make solid motor mounts and will make them around this engine.

inactiveuser92616

so which specialty vehicle manufacturer do you work for?
I am thinking Panoz...

BC

How Solid?

Mike Simard

Patrick, the Panoz factory is nearby actually. Also close is where they make the G Force indy car chassis. My company is a CNC and EDM job shop specializing in parts that are difficult to produce and there are some like that on those chassis but that's a tiny fraction of our business.
I do have a dream of designing and building a V12 engine someday and the thought of it being used by Panoz has crossed my mind several times...Then I'm smacked upside the head with the wet Salmon of realising I have to get back to work

Brendan, I don't know how to mount the engine yet. Either a steel weldment or aluminum machining, some sitting in an empty engine compartment chin scratching should help. I do believe in solid mounting although some might disagree, even for a race car.

If anyone wonders about head and main stud lengths, here's what they look like. The head studs are on top. The mains have an odd longer 12mm stud. The hole where the dowel sleeve is installed needs a 10mm longer stud in that one hole only, at least on an 87. These head studs have longer threads to be used with the pre or post 89 thickness and the mains either with or without the girdle. Also different is that the mains have a finer pitch on the nut end.