Oil tests - PeachParts Mercedes-Benz Forum

t walgamuth · #1 09-08-2016, 06:29 AM

I got my Acura K20 a2 powered Lotus 7 replica race car all together a few weeks ago. I ran it one weekend at Grissom at a test and tune, getting in about 12 runs without incident. We decided to send it to a racing engine shop to have it "dyno tuned". They run it on the dyno over and over, testing various combinations of cam timing, the whole process taking about four hours. Unfortunately the bearings started making noise and they shut it down.

The tuning shop says my local machinist probably did not build the motor correctly. My machinist says they probably overheated the oil until it lost its lubricity, thusly damaging the engine. The oil was mobil one 5w30, brand new. It looks very dark and smells burnt now.

If I send some of the oil in will they be able to say what damaged the engine?

Final damage assessment: damaged rod bearings in #1 cylinder, damaged and spun bearing in #3 cylinder, bent piston in #2, and bent crank. Everything else looks good.

Also, what oil lab is recommended?

barry12345 · #2 09-08-2016, 10:13 AM

Really tough break and hard to bear. Or it would be mentally for me. Personally as you know I am not an expert.

Still I would not expect any pointing of a finger so to speak with an oil test. Just my opinion.

I could be wrong about that but all I would expect to find is the oil has metal in it and the oil is burnt basically. No matter what the cause was. Even finding coolant presence in the oil might have occurred after the initial issue.

Unfortunatly substantial damage has occurred as well. I wonder if the oil pump quit though?

link · #3 09-08-2016, 10:15 AM

What a bummer.

I don’t have a direct answer to your question, but the burnt oil suggests over-heating and/or incorrect cooling.

How much oil does it hold? Even if a part failed, that itself would not cause the oil to burn at least in short order.

Does the damage amount to a rebuild or replacement? I’ve had engines 2x that had some of the damage you noted and in both cases a replacement was suggested.

Idle · #4 09-08-2016, 11:12 AM

I knew a guy about ten years ago that build up a serious engine in his Ford Mustang. Then he burned it up.

He put in some real money to discover the cause since this was not going to be a one time thing.

To keep it short: He installed a higher flow oil pump but he did not increase the size of the holes in the heads that allowed the oil to drain back into the sump. So the oil could pump to where it was needed with sufficient flow and pressure but it could not drain back down as fast as it could be pumped.

So all the oil went to the top of the engine, the sump ran low, the oil pump caveated and the engine burned up.

So all in all expect discovering the root cause to be a complex process.

t walgamuth · #5 09-08-2016, 11:14 AM

Well a replacement is impossible since not much is stock on the engine. Stock block, crank, valves and head....aftermarket valve springs, cams, pistons and rods.

Even with the bearings buggered it ran and held excellent oil pressure so the oil pump seems good.

t walgamuth · #6 09-08-2016, 11:18 AM

Quote:

Originally Posted by barry12345

Really tough break and hard to bear. Or it would be mentally for me. Personally as you know I am not an expert.

Still I would not expect any pointing of a finger so to speak with an oil test. Just my opinion.

I could be wrong about that but all I would expect to find is the oil has metal in it and the oil is burnt basically. No matter what the cause was. Even finding coolant presence in the oil might have occurred after the initial issue.

Unfortunatly substantial damage has occurred as well. I wonder if the oil pump quit though?

its a tough break but really by now I expect things to fail. Its nothing like having a loved one in a possibly fatal condition.....just money and time. I have limited supplies of both but adequate to cover this.

Aquaticedge · #7 09-08-2016, 12:44 PM

Blackstone labs never used them, but I've heard good things about them
Blackstone Labs

t walgamuth · #8 09-08-2016, 08:01 PM

Thanks! I'll check them out.

OM617YOTA · #9 09-08-2016, 11:29 PM

That bites. Looking forward to hearing what happened.

I enjoy reading about your autocross adventures, both building the car and racing.

JB3 · #10 09-08-2016, 11:35 PM

Quote:

Originally Posted by Aquaticedge

Blackstone labs never used them, but I've heard good things about them
Blackstone Labs

x2 on blackstone. Ive used them a few times.

t walgamuth · #11 09-09-2016, 07:05 AM

Quote:

Originally Posted by OM617YOTA

That bites. Looking forward to hearing what happened.

I enjoy reading about your autocross adventures, both building the car and racing.

Thanks! I enjoy writing about them. When stuff breaks I long for my Miata but when I'm on course with the D mod, it is pretty exhilarating stuff!

Zulfiqar · #12 09-09-2016, 10:12 AM

Blackstone labs are great for this work.

btw - did you employ a larger sump? Hondas are generally not too stellar in the oil capacity range, most hold only about 4 quarts at best and these engines do not employ dedicated large oil coolers to help them out when they are flogged too many times.

t walgamuth · #13 09-09-2016, 10:42 AM

It has a dry sump which contains 6 quarts. It was about a quart low after the dyno work. No oil cooler as with an autocross car you don't really get much time in at hard load. It never runs hot even on the hottest day but does not have an oil cooler. I am working on remedying the lack of an oil temp gauge.

I just talked to Blackstone and they said they can tell if the oil has been overheated so I am sending them a sample.

barry12345 · #14 09-09-2016, 01:19 PM

The oil will smell burnt if it has been overheated as well. I do agree that blackstone may have a more definative test though.

One consideration is the engine had little run time after being rebuilt. Perhaps not enough break in time before being really stressed? Usually a factory engine intended for serious use by a racer gets blueprinted I believe. This is a process of changing clearances to deal with the greater stresses etc. that it will see.

Even todays factory engines get some run in time in before being installed in cars. Long ago we used to get serious instructions on the use of new engines for certain initial periods.. Back then perhaps they had no factory run in time at all.

t walgamuth · #15 09-09-2016, 01:21 PM

I discussed run in time with my machinist. Since we were using the bores without boring again he felt that break in time was minimal. Maybe wrong thought?