What you see here are the interesting remnants of my '80 Euro S engine. It grenaded two weeks ago while doing PCA DE at Brainerd Intl. Raceway. At that instant I was about to shift so it was turning about 6300RPM. The damage was pronounced.

A few questions have been raised and I'll take a shot at them here.

What was the failure?

Clearly the #6 bearing was not getting lubricated correctly. The crank journal shows discoloration on that half of the journal and just one pair of bearings shows wear. Those show copper over more than half of the surface.

Why was it worn?

This is harder. I believe there's a two-part problem in the 928 engine. The first is the proclivity to aerate the oil. The pan is too close to the crank so the oil gets whipped into a foam, for frappe' if you will. The oil gets sucked into the engine and then the second part of the problem takes place. With the way the oil is distributed, air or foamy oil will go into the second crank journal and from there into the rod bearing. Do that enough and the bearing wears metal-to-metal.

What oil were you running?

The vaunted Amsoil 20w50 racing oil. Good pressure when hot and cleans off the hands well. Didn't save me this time. I had changed it this Summer and had 2 days at RA plus that trip on a fresh fill.

Any warning?

Nope. Just the sudden noise of my engine beating itself into small chunks. (Check the engine pic.)

Did the scraper play a part?

Well, it didn't save it. I'm really perplexed about the role of the I-J crank scraper in all this. If you followed the "crank scraper at RA" thread you'll know that I had problems with a newly-installed crank scraper right off the bat. While I was a "true believer" the results were an increase in oil ejection. (Looking at my '04 build plans I see "crank scraper" on that list.) With the new, steeper drains there was still more ejection than previosly. Experimenting with that surely didn't help any. If it is making foam it is sucking foam. Let me say that the scraper isn't going back into the new engine.

What lessons were learned?

- Change the bearings whenever convenient. Perhaps it I changed them last Winter or in May I'd be running. Maybe it would have blown at "928s on the Autobahn."

- Check the oil filter and have oil analysis done. I know certain racers do this and I've gotten religion on it. I'll be the zinc content would have been off the chart. Looking that the plug magnet is a poor substitue. Bearing coatings aren't magnetic.

Looking at the crank I noticed that the oil flow isn't quite what I expected. The drilling on the crank forms a "Y" inside the journal and not a "hockey stick." People have analyzed the cranks and said that the oil "flows backwards against centrifugal force." This is an early crank and the oil flows from the journal directly to the #6 bearing. The #2 bearing taps off that tube and the oil on that leg is still flowing further out. People have speculated that the early cranks have some advantage and maybe different drilling is it. Didn't matter in this case.

Another issue with the 928 oiling system is the way the oil flows inside the block. Looking at the lower block half it's clear why the 2/6 bearings take a beating. Given the oil foaming problem, the rod bearings most subjected to it are 2&6. Oil flowing to the first journal (1&5) passes the passage to the left head and foam will shoot up there. Oil that gets past 2&6 will next go to the third main journal which also feeds the right head. That protects the rear two rod journals. Foamy oil that gets past the filter comes out close to the entrance to the second main journal, which feeds 2&6, so that's where the damage is most severe.

A remedy to this may be to change the opening to that journal to block the foam. This could be done by drilling the passage to the bearing lower and putting some metal across the top. Then the foam would go to past that journal and to the right head. Just an idea.

Not asking for parts, mind you Randy, but the 4.7 block is toast, the crank is damaged and the two rods and pistons are shattered. One exhaust valve is obviosly bent but the heads look good. The pistons were thrown up the cylinders at an angle.

Going to rebuild it. Is there any other option?

 

Nasty!!

I just finished pulling a Nissan engine that also spun the connecting rod bearing.

 

NASTY!!!

great analysis. Intuitively, im thinking the crank scraper is a bad thing, but i dont know much about these things. seems like fling'ing oil all around can be a good thing. again, what do i know about this, except scot's 2-6 bearing welded itself to the crank and forced the engine to lockup. (no broken rods)

so, between the two of us, we almost have a complete 82ish euro engine. Scot's block needs some clean up on #2 and #8 cylinders, after the slow speed second time, while we strarted it up for the first time, lockup. Probably an over sized piston should do it there in the only two damged holes. the rest of the rotating assembly looks pretty good and is balanced well. (under a gram)

maybe its worth a bore to 5 liter and use the good rods to make it work. its all set up for use with the later crank with the larger oiling holes. that could be part of the issue too. you have the older crank with the tiny oiling holes for the rod bearings.

really sorry to hear of the loss. i know what a pain (but kind of fun)
it is building these things back up!

MK

 

that sucks glen....i hope you get'er better than before when you're done! Just curious, did you have the full boat crank scraper including windage tray? I opted for #2 and decided not to spring for windage tray. I dont plan on tracking my car, mainly for street use when I'm done.

 

I was running the "#2" setup of crank scraper and head drain deflectors. No windage screen. I also had a sump cover that seemed effective. I plan to straighten that back out or fab another one.

 

Good Heavens! This gives new meaning to Granading! The engine really does explode! Ohmygosh!

Harvey

 

wow, that definately looks like it exploded! Was it as loud as it looks violent!
Pretty sure thats similar to what David Lloyd experienced when running this past Feb. at Sebring, was reving above 6000 about to shift when a bearing failed. Maybe the same #6, not certain & not sure how extensive his ultimate damage was once he got it all apart.

 

Damn, that sucks!

So much for the Amsoil as the savior myth. I guess for a shark to do moderate track duty schedule of yearly rod bearing changes is a good idea. That idea for a 3 piece crossmember looks good for that.

Good (better) luck with your new engine when you do it.

Jim

 

I would suggest reading Smokey Yunick's book, specifically the chapter on the lubricating system. Even back then, he was a huge proponent of dry-sump oiling systems in race cars due to g-forces and it's affect upon the oil.

He went on to say the wet-sump is totally inadequate for a race car, and if one must run a wet-sump, one must do anything and everything in an attempt to control the oil in the pan and around the crank using a combination of scrapers, screens, baffles, and trap-doors as 'Kevin Johnson' of Ishihara-Johnson (IJ) states throughout this thread:

https://rennlist.com/forums/showthre...0&page=1&pp=15

Smokey also stated that even with a dry-sump, one should use crank scrapers and baffles to separate the oil-cloud from the spinning crank, which Smokey says looks like a big ball of 'brown taffy' around the crank, and get that oil back into the recovery tank.

I think the strongest evidence of the effectiveness of the IJ system comes from the Dutch Stallion 928 team, which has the entire IJ kit installed on their engine, unlike Glen's partial setup. The Dutch Stallion team has over 32 RACING HOURS on their engine with NO FAILURE:

Post #221:
https://rennlist.com/forums/showthre...&page=15&pp=15

Based upon that compelling evidence, the IJ system must work as a 'sum of it's parts', and is incomplete otherwise, and why the kit is only sold with all parts included; in other words, one cannot buy just the scrapers as one could in the past.

Another piece of the 2/6 puzzle is the crank itself. I wonder whether the 32 hour Stallion engine has a drilled crank too, since Mark Anderson blew his 2/6 WITH his dry-sump installed, and never 2/6'd again after getting his next crank drilled 'Chevy-style'. Glen stated that he knowingly chose not to drill his crank the last time he rebuilt his engine, so that *may* be a contributor to the expired motor too.

 

I have a spare 4.7-litre engine. Btw I think the foam is only one of the issues here. IMHO an accusump would have saved you here, and certainly a drysump would have, IF one assumes foaming was the cause.

 

all good points.

so, it sounds like the chevy drilling is most important. Amzoil can help due to less foaming, and a slight overfill must help too.

One of the obviuos things ive seen here is that these recent failures were not in high G loading situations. generally, you hit that 6600rpm as i do, coming out of turns. all andersons video and mine show this , even at tracks like RA..

I think this points to a plain, inability for the 928 engine (in some cases) to run at above the 6000rpm range, when hot.

as far as statistics, ive got over way over double, and more like triple the number of racing hours vs the duch Stallion now (near 100 hard racing hours). All with a stock 928 S4 engine with a set of headers! (320 now, and 335rwhp at the beginning.) no coolers, scrapers, etc. Be interesting to see if the holbert engine has anything special inside. Hope i dont have to find out anytime soon!! (knock knock). ( when i cut the filters open, after every 3 racing weekeneds, there are no signs of anything shiney inside.)

One thing for sure, the oil holes on Glen's crank are very small compared to the later cranks. i know you loose pressure for flow, but at 6,000rpm plus, im sure the flow is not the issue for the larger holes and are probably essential for engine survival. amzoil and later crank or drilled crank like the "chevy" maybe the reason for the holbert engine racing longevity.

MK

 

I just want to throw in some more confusion on this thread here... On my two recent outings at the Nurburgring the car showed drops in oil pressure from 5+bar at 4500rpm to 3bar during BOTH left and right turns... Moreover, the turns were all at the end of flat sections going into uphil bits of the track. Oil pressure drops were observed only when de-celeration for the bend turned into acceleration as I was hitting the apex. That tells me that the oil is sloshing about the pan and uncovering the oil pick up. Thus, a I-J crank scraper, windage tray and a sump baffle cannot be a bad thing at all.

BTW, the engine is a completely standard and has been recently rebuild and blue printed - 300RWBHP. I run the car on racing suspension, but street rubber as a precaution.

I am about to make a dry sump pan based on a design which has been used in the UK for a season by a 928GTS with over 40 hours of racing on it. Would any of you guys be interested if I install it on my GT and it proves to eliminate oil aeration and oil ejection? The cost will be around $750 + your old pan for the new one... Scavenge pump, lines and oil tank are extra...

Alex

 

whew,,, thats going to leave a mark....

 

Overfilling will lead to more foam because the raised oil level will hit the crank more often. From what I've read of 16V (especially Euro) engines run hard, they will puke any extra oil out rather quickly. The first time I changed my oil, I put 8.5 quarts in and the level dropped pretty quickly. The second time I filled to the lower oil level and didn't notice any loss. That was a little under 8 quarts. Since then I've only put 8 quarts in and have not noticed any oil level drop after the first run even with seepage covering the entire bottom of the car.

BTW, 8 quarts on my car is 1/8-1/4" above minimum on the dipstick.

 

You have two?