rocker oil supply starving bottom end

[Pete Lewis]

dont forget the Triumph designed oil feed to the rockers is an interrupted feed via a offset slot machined into the rear cam journal so it only get one squirt for each revolution as the slot aligns with the oils ways, if  triumph felt a full flow was needed they would not have designed this fairly standard means of rocker oil  supply.  many  older cars have this in place .

Pete

[JohnD]

piman wrote:

Hello John,

did you notice a loss of oil pressure before the bearings went?

I would add that my car is used as a road car, but I also fitted an oil cooler (with thermostat) as I was planning some form of competition with it sometime. Monitoring the oil temperature confirms that it is totally unnecessary on a road car even on the hottest day and driving briskly (U.K.).

Alec

Glad to have your support in thsi matter, Alec, and others, of course!
It's so long ago, I can't remember, but I think suddenly the oil pressure was gone, or nearly.    I've lost it, but the 'run' bearing was like a sunburst of melted metal!

oily carpet,
I'm sure you're right, but the thermostat redirects the oil flow to bypass the cooler to keep the oil at working temperature, or to let it heat up to that after a cold start.    Is the 'bleed' an engineering compromise?   Total redirection might need a more complex, more expensive tyoe of thermostat.

Gaz,
Extra oil in the system is also a point of interest.  In a series that didn't allow coolers (TR3, I think) Kastner made extra large sumps that increased capacity by SIX PINTS! (2.72litres!)  and achieved nearly as much cooling effect by keeping the oil in the sump longer, where it could lose heat to the passing air.   Ribbing the sump might help the last.

John

[piman]

Hello Gaz,

my temperature sensor is fitted in the sump, and I don't think I've seen a temperature any higher than eighty degrees and generally lower. I also added a 1 inch strip around the sump to increase it's depth , easily done as I was fitting baffles anyway.

Alec

[JohnD]

Have you calibrated your gauge, Alec?
80C sounds quite low.

80F would be very low indeed!
John

[uksnatcher]

John.I have seen the Kastner bigger sump on a website and the mod required to do it but i cant find it, sounds like a good option and a finned/ribbed sump is only an option on a cast sump??

Alex. the oil temp in the sump is cooled...by the sump, i assume its a sensor in the drain plug area so sensing temp at the bottom of a body of cooled oil is not ideal  :-/

John / Oily carpet. the bleed past the thermo plate sensor stops the build up of old oil in the cooler collecting and the thermostat to work efficiently surley not?

[piman]

Hello John,

it was a brand new gauge (Mechanical) at that time.

Gaz, there will not be a lot of cooling in a sump continually being fed by oil directly from the engine. Also it is the oil that will be delivered to the bearings so I am happy with that sampling point.

Alec

[uksnatcher]

piman wrote:

Also it is the oil that will be delivered to the bearings so I am happy with that sampling point.

Alec

Thats a good point Alec and i am looking at doing the same with a sensor in the sump hence asking , cheers mate.

[JohnD]

No argument, Alec, that's what I do, but I'd take the calibration with some salt.
John

[piman]

Hello John,

fair comment.

Alec

[69vitesse]

The optimum oil temperature is 90c. Overheating oil is far deadlier to an engine than low oil pressure. If the oil overheats, both the pressure, but especially the oil film breaks down and your engine is toast in more than one sense.

IMO, much of the problems with oil pressure in Triumph engines is temperature related, they really have far too little oil capacity as standard for the size of th engine. It should be noted Triumph always offered an optional factory fit oil cooler back in the day. They clearly knew something was less than optimal.
Ideally, I'd increase the sump,capacity by 50%, but thats not practical due to space constraints.
Adding an oil cooler circuit effectively does the same, and the extra oil dribbling around the cooler circuit all adds to the ability of the engine to keep its oil temperature with limits.

[herald948]

2729 wrote:

It should be noted Triumph always offered an optional factory fit oil cooler back in the day.

Right, along with many other items "for competition use"!

2729 wrote:

They clearly knew something was less than optimal.

Sure, for stock components under "competition use" stress.  ;)

[69vitesse]

herald948 wrote:

Right, along with many other items "for competition use"!

Sure, for stock components under "competition use" stress.  ;)

Nope, the oil cooler kit for the TR5 was listed as a Stanpart dealer fit accessory along with things like a door mirror or a continental touring kit.

[Nick Moore]

I don't think 'competition use' was the only reason for a dealer-fitted oil cooler kit.

A friend bought his TR6 brand new in 1970. (Royal Blue, black interior, wire wheels, totally gorgeous). He observed that when running at 100 mph for 30 minutes or so, the oil pressure would drop alarmingly. Presumably this was before the 70mph limit was introduced...  His dealer failed to find anything wrong, so he took it back to the factory. Those were the days... They tested it and explained that the low oil pressure was because he had driven it at 100mph for 30 minutes and the oil was getting too hot. They also told him that his TR was "one of the good ones, quicker than most" which is a bit of an admission from the factory, but it made his day. The tester also explained that a vibration he'd felt was because his tyres weren't round, so would he like some new ones?

Lesson learnt. He emigrated to New Zealand with the TR, and no longer exceeds 100mph for extended periods. The car's never been restored, the engine's never been opened, and it's still quicker than most.

[69vitesse]

Indded Nick,

Many people don't seem to realize how much heat the oil is responsible for drawing out of the engine, 25%.
It gets too hot and things like the crank get too hot and its a vicious circle as your oil film breaks down and pressure drops. Only the oil is keeping your rods, crank and pistons cool.
Back in the day, you'd be hard pushed except on the Continent to be able to drive flat out for more than an hour. This is one of the reasons German and Italian engines tend to be so robust, they have had to be built to withstand driving all day on the Autobahns and Autostrada at very high sustained speeds.

[herald948]

2729 wrote:

Nope, the oil cooler kit for the TR5 was listed as a Stanpart dealer fit accessory along with things like a door mirror or a continental touring kit.

Perhaps I should have substituted "sustained high speeds" for "competition use"?  ;D

[69vitesse]

herald948 wrote:

Perhaps I should have substituted "sustained high speeds" for "competition use"?  ;D

Thats correct. That was what started bring the issues with undespecifed oil systems to the fore, the arrival of the Motorways.
Prior to the M1, the cars that British Leyland etc were making were adequately specified. But the spread of the Motorways network in the 60's cruelly exposed the all too often limited engineering unable to take sustained high speeds and the RAC and AA did a roaring trade towing off cars with burnt out bearings.
.In the 60's and 70's, 40,000 miles between rebuilds was considered good going. I can still remember the 100,000 Mile Club, and a car that ran up 100,000 miles would make the headlines in the local press!

[69vitesse]

And ceramic coating your piston tops wil aso cut down the amount of head dumped into the engine and oil system, and improve the engines performance.