Ok, BHDT. That crank looks saveable to me. When mine seized, the 2/6 journal was almost black it was so hot. I had to get the shells off with a chisel. This journal looks like it wasn't overheated too much. That means it can be saved. The 928 crank is of good material, and crank breaks are almost unheard of. You can even go oversize bearing on that one journal if you so choose. The machinist will be able to advise you better. It should be checked for cracks.

Remediation. There are a bunch of things that can be done. I'm a big fan of the GTS baffle. Although I haven't run my car yet, it looks like a good approach to stop the sloshing with cornering and keep the windage to a minimum. The other thing I would think about next is a dry sump. A lot of older aircraft have dry sump lube, and it will help a lot with the frothing if the tank is separate from the crankcase. Drilling the crank while it's out is also a good plan, as it keeps more oil in the shells moving under pressure. I can't speak to the Accusump system as I've never used it. Also, while I was in mine, I deburred all the galleries from the oil pump through the lower section. I also deburred the outer edge of the block where the oil drains back from the heads. This was under supervision of my machinist. He said the sharp edges of the oil galleries makes the froth worse in the oil.

 

 

We knew Mark offered a warranty on used parts bought from 928 intl. but who knew he offered that same warranty on used cars bought there?

 

Outstanding offer Mark!



Brian, I think you have some new found hope!

 

Yeah, I have had a few C5Z06 drivers tell me that I need to put an LS1 to get rid of "that oversized, unreliable Porsche thing". Then they blush when I ask them how many LS1s they've cooked... At least 2 each in under 2 years. Then I get the "It's only $6k for a crate motor!"

 

hardly. Did you see my fuel curves on the original holbert engine?
12.5 to 13:1 from top to bottom. even the best optimization could yeild very little positive results from this baseline. Now, spark and mixture of spark and fuel is truely where the optimization comes from. Proof is in the pudding.
335rwhp out of a stock 5 liter S5 with GT and 85 cam. 7 years of racing.
Thats a pretty tough bandaid!

even now, im real rich at 11.5:1, but the engine is safe, plugs are clean, but power is down 15 hp we all guess. I will lean it out a bit when i get on the dyno . curve was flat as a pankake. each turn raised the entire line. Pretty effective actually.

mk

 

You are the MAN!! Helping out the 928 racing community!!!

Brian, take advantage of this offer with the clutch. Anderson set me up with the modified dual disc pressure plate and it did just what he said it would. FIXED the slipping issue with my 60more HP and 90ft-lbs of torque!! Probably the limit as joe and mark both said, of near 420rwhp before you need the special stuff.

mk

 

Yep. The gold vet, the monster camaro, the other black powerful vet, over the 7 years have all toasted their motors trying to keep up with me. I mean while, im not spending time fixing, im racing. I dont make fun of them, and they dont of me. We all know in this sport, things break. BUT, I have been doing pretty well with what is supposed to be " not designed for racing".

I think the spun bearings are caused by several factors. Some of which are under our control, without mods. others can be certainly reduced in risk by making changes. (i.e. drilled crank, drysump, proper mixture etc)

mk

 

This really sucks, Brian.

I guess you have to look long term. Whatever course you take, make sure it allows for about five seasons of SCCA competition with no further engine drama.

Every track day you miss this year, equals several hundred dollars of engine rebuild money. So here's how you handle the wife....."Honey, I've decided to forego several track day's in order to beef up the Widow so that I won't be spending our hard earned money on repairs later on."

Good luck.

 

Wow, you're good.

 

Well I had pulled the pan a couple days ago (then got caught up with other distractions.

I decided to pull and inspect/replace the rod bearings as I have new ones sitting around here anyways

I pulled the #2/6 rod bearings. This engine has WELL over 300k km on it, and I am throwing the drysump on it to prevent issues when I take it to the traack with full racing slicks.
I have 3 heavy track days with fairly sticky tires which I ran at the limit for cornering each time out.
I never did pay any attention to the oil pressure, so I cannot tell you if it dropped down, but I never had lifter tick when pulling back in, and I always ran lower or just below the add line on the dipstick.
There is still some of the origonal top coating on the bearings (not much), but the bearings were OK. Not new by any means, but if the car was a street car they would have lasted another 200+k km.
I am going to get some bearing assembly lube, and will be putting the new bearings in (after confirming tolerances), and buttoning them back up. I will then be installing the crank scraper/windage tray assembly from I-J, and putting the drysump pan onto the car.
That is after I find some Yamabond-4 (thanks for the info Louie!)

Keep in mind that this car is driven extremely hard, and I pushed it often, I went roughly 15k km on one oil change as well. There has been no extra wear shown up because of this. But to be fair I had abit of a leak and was putting lots of fresh oil in

 

Mark A is the MAN.....

Thanks to his generous offer my clutch problems are solved....an upgraded pressure plate, with increased clamping force + a disc will take care of it!

I hope to have the crank issue resolved in the next couple days too.....

The power of Rennlist saves the day AGAIN....

 

Great offer by Mark. I would take that and build on it, at least for the drilling of the crank (Greg has mentioned a program that may or may not still exist since Jay's Passing at taylor Machine) - AND an accusump an effective "Bandaid" until a total drysump.

 

What 'cha doin' with the affected con rod ????

It might need some thought and consideration.

$0.02

 

Jim
Good question.....I didn't even think about it?

Brian