Killed another engine

#1

I’m still doing DE’s, not racing yet; but the car is mostly spec e30 prepared. The last two DE’s have claimed two different engines. Both engines have metal in the oil, and low oil pressure. The engine I killed today at Road Atlanta was working great all weekend until the last session. The oil pressure started falling off (about 45psi down the backstretch, 7psi at idle), and once I pulled off track I found metal in the oil. This engine shared no components from the old engine, but both have the same symptoms.

I run Mobil 1 extended life 15W50 with ZDD additive, filled 1/2 quart over full. I did notice in turns 5 and 10a the oil pressure would go to zero. In turn 4 it would drop to about 25psi. Could this be whats causing my problems? I know the solution to this is an accusump, but I don’t see accusumps on everyones car.

#2

http://www.crank-scrapers.com/

#3

so without a crank scraper or accusump, will that loss in pressure kill an engine that quickly?

#4

Yes it will. Anytime you see less than 20 psi while on the power you should be concerned. The crank scarper Mike posted the link to should get the job done but leep your eye on the oil pressure in high speed left hand turns.

#5

And run a qt high, not a 1/2qt high. Factory3Performance is a good place to get your crankscraper.

As a general rule you should see about 10psi/1k rpm. So 45psi would be fine if you were around 4500revs. And in my limited experience, 7psi at idle is no big deal.

Are there symptoms other then metal in the oil? Any ticking from the bearings?

#6

Interesting. Let me just share my experience. This is my third season racing and I have never overfilled my engine oil. I have installed a crank scrapper last month, but did not have one for the first two seasons and I’ve raced at Road Atlanta more than six/seven times. The last event was the 8 hour enduro and did not have the crank scrapper for that event.

#7

Gasman wrote:

I still don’t have a crank scraper. I know I need to get one, but hate to mess with a good thing. 3 years tracking this motor now with no problems. I do run about 1/2 a qt. more oil!!

Never seen the oil light come on!!

#8

Ranger wrote:

[quote]And run a qt high, not a 1/2qt high. Factory3Performance is a good place to get your crankscraper.

As a general rule you should see about 10psi/1k rpm. So 45psi would be fine if you were around 4500revs. And in my limited experience, 7psi at idle is no big deal.

Are there symptoms other then metal in the oil? Any ticking from the bearings?[/quote]

The first motor with the same symptoms was torn down, and the bearings were trash, and the crankshaft needed to be ground undersize 0.020" in order to save it.

The motor this weekend has gotten louder, and on the drive home lost another 5 psi oil pressure on the top end. Up until the last session Sunday, the oil pressure was at 65 psi at all revs above ~3000 rpm. And hot off the track at idle still saw ~25 psi. Also, I was checking oil every session and never saw metal until the last session. So, something changed for the worse.

The zero pressure in 5 did not come until the end of the weekend when I started really carrying some speed through there. It was not happening the whole weekend, but for most of Sunday.

Time for engine swap numero 5 :angry:

#9

6 months after buying my car I was replacing bearings and installing a crankscraper. So luck varies.

Neither of which I now possess because Molitor swiped my block when his head punched holes in my pistons. Grumble grumble.

#10

BMW built my motor, and the more I read around here, I will keep it that way even after this motor implodes. I have a spare, after that it will be another junkyard motor. If I ever decide it’s time to plop in a fresh motor, I will buy a long block from BMW!!

#11

Obviously there will guys that have no crank scraper or anything and have run fine for years, but the fact is it helps maintain oil pressure in long sweepers and its cheap. Its your decision and motor but why wouldn’t you install a $100 part that we know helps with oil pressure? It might have still failed anyway but it seems like cheap insurance to me.

#12

Elephant4 wrote:

No doubt the next engine will have either this or an accusump…or both.

At this point I’m really just trying to figure out what happened to the engine. If this drop in pressure killed it? Or am I chasing another issue?

How common is main bearing failure like this in these cars? Does not seem too common for everyone else, but I can’t seem to keep one together…

#13

Elephant4 wrote:

I agree, I wasn’t trying to argue they weren’t needed. After this weekend I won’t see the track till June, so it is on my long to do list!

#14

Gasman wrote:

Well you are not going fast enough in the corners for the oil to slosh anyhow…:laugh:

Sorry Steve. I couldn’t resist :kiss:

Don

#15

Don, I had a feeling I was setting myself up for that. :wink: You could have said, hey Steve, don’t you use Amsoil? I would have said, Why yes Don, I do, why do you ask?

Wstukas, might want to rethink the accusump option if you intend to race in the series. The crank scrapper is legal whereas the accusump is not.

#16

Gasman wrote:

[quote]Don, I had a feeling I was setting myself up for that. :wink: You could have said, hey Steve, don’t you use Amsoil? I would have said, Why yes Don, I do, why do you ask?

Wstukas, might want to rethink the accusump option if you intend to race in the series. The crank scrapper is legal whereas the accusump is not.[/quote]

I respectfully disagree.

9.3.1.6.3. A pressure accumulator/“Accusump” is permitted, and the location of the
accumulator within the bodywork is unrestricted, but it shall be securely mounted.

#17

Elephant4 wrote:

I agree…Each car is different. There are cars with no scraper that run fine. There are cars with scrapers that blow up. I think it has more to do with the bearing health before one starts running it hard. If one’s bearings are already worn from 200,000 miles of less than avereage maintenance (as in a junkyard engine), they are not going to tolerate much abuse, even with a crank scraper.

I did not think to install a scraper when I was building my car and now I wished I had. I saw an oil light for the first time the last time I had the car out. An oil change revealed some (not much) fuzz on the magnet for the first time ever as well. A sample of that oil is at the lab for analysis as we speak.

There is one school of thought borne out of showroom stock racing from 20 years ago that synthetic oil provides that extra bit of protection that will allow the bearings to endure a second or two of low oil pressure. I have been testing that theory for years and up to now it has proven effective. We’ll find out how effective whe I get that oil analysis report back!

Don

#18

Scott, thanks for correcting me, I guess this is new for 09?

#19

Gasman wrote:

Accusump has always been legal as far as I know.

#20

:huh: Yes, I see the changes for 09 are highlighted and this rule isn’t. Don’t know how I missed it. Thanks again.