Engine Failures at LeMans

[Austin Healer]

Oil supply and clearances

are not the only issues.

On page 112 of the Taylor

book, it was mentioned the

cars lost oil pressure on the

Mulsanne STRAIGHT.

You NEED to keep control of oil

Temps as well.

Clearly, Rootes had more issues

than they could keep control of.

...And maybe one major issue

was when Norman Garrad left

the competition Dept?

DW

If they hadn't already destroyed the bearings from oil starvation on the corners, the aeration of the oil from windage was the likely culprit on the straights....

 

[spmdr]

BTW, Bigger picture time...

Was the oiling system a problem during the RACE?

Clearly it had problems in development...

A review of at least one History account

reports the first Tiger to drop out of the race

ran 3 hours.

The second Tiger ran 9 hours.

I would challange anyone to achieve that with a major

faulty oiling system or slack tolerances.

The reported failures were piston and

crankshaft.

Both could easily fail with a perfectly/adiquate

functioning oil system.

DW

 

[Austin Healer]

BTW, Bigger picture time...

Was the oiling system a problem during the RACE?

Clearly it had problems in development...

A review of at least one History account

reports the first Tiger to drop out of the race

ran 3 hours.

The second Tiger ran 9 hours.

I would challange anyone to achieve that with a major

faulty oiling system or slack tolerances.

The reported failures were piston and

crankshaft.

Both could easily fail with a perfectly/adiquate

functioning oil system.

DW

Don't think so! Slack clearances would lead to low oil pressures and racing on a road course would cause oil starvation (from surge) in the corners. At the time windage trays or crank scrapers were not the norm. Dry sump oiling was much more common in formula jnr. and formula 1. Between the oil surge and the windage issues, I'm amazed that either engine lasted as long as it did. In any event, the lack of rigidity in the 260 crank journals is well known... It's why they had a 5K redline and a 2.88:1 axle on the road cars.

Dry sump oiling probably would have allowed the engines to run the full 24hrs.... assuming the crank oil clearances were acceptable.

 

[michael-king]

In any event, the lack of rigidity in the 260 crank journals is well known... It's why they had a 5K redline and a 2.88:1 axle on the road cars.

I thought the low redline in the stock 260 was the push in rocker stud's pulling out at higher rpm, and if you went to screw in up went the redline

 

[65beam]

Was there ever a comparison of Shelby's engines versus the engines built for the Tigers or is everything based on speculation?

 

[michael-king]

Was there ever a comparison of Shelby's engines versus the engines built for the Tigers or is everything based on speculation?

Comparison of what....???

The Cobras that ran that year were 289s with different carb setup and sump.. which was covered earlier in the thread.... What exactly are you trying to compare?

 

[65beam]

Comparison of what....???

The Cobras that ran that year were 289s with different carb setup and sump.. which was covered earlier in the thread.... What exactly are you trying to compare?

The size of an engine or the fuel used doesn't mean anything. There's a lot more to engines than just bearings or the clearances. Oil samples will show the presence of wear metals, copper, coolant, unused ingredients of the additive package as well as many other engine oil containments that determine why there was an engine problem. If you have more than one identical spec engine the comparison of the used engine oil will show you reasons for the problems. That's the comparison engine builders and oil suppliers look for. If a customer of ours has what he thinks could be an oil related problem, an oil sample is the first thing to be done. There's no blaming or finger pointing of anyone else. The deal with Shelby is just speculation and conjecture. Oil samples processed by a lab have been around forever so it's not something new. It's worth looking up "use of oil sampling" and you'll get a clear picture of why industries, fleets and individuals use the service. Most race teams use the service especially teams that run dirt track circuits.

 

[michael-king]

Comparison without context means to compare . That could be spec, manufacturer of parts.. materials etc...... Rootes at the time used shell and Castrol mainly ...Shelby may have used different oils, to Rootes.

As for comparing oil samples yes , they the ability has been around for a long time .. if they did analyse the oil I doubt there are records of it still accessible and can't imagine they got what results Shelby got if they did an analysis.

If Rootes had low oil osi issues from practice onward.. they may have cared less about the reason than refund.. and they still bought engines for the rally Tigers later iirc... So obviously they decided Shelby was still worth dealing with.

 

[65beam]

Comparison without context means to compare . That could be spec, manufacturer of parts.. materials etc...... Rootes at the time used shell and Castrol mainly ...Shelby may have used different oils, to Rootes.

As for comparing oil samples yes , they the ability has been around for a long time .. if they did analyse the oil I doubt there are records of it still accessible and can't imagine they got what results Shelby got if they did an analysis.

If Rootes had low oil osi issues from practice onward.. they may have cared less about the reason than refund.. and they still bought engines for the rally Tigers later iirc... So obviously they decided Shelby was still worth dealing with.

I am a certified lubrication engineer with close to 40 years in the business so I would be more than glad to answer to the best of my ability any questions you or others may have as far as lubrication. I did talk with Shelby a few times over the years and I don't think he was the type of person to do intentional harm to a customer.