Big end bearings.

[Clive]

I had to be recovered back from STAR, well Cherwell Valley services. Story is that a few months ago on a targa rally the oil pressure droped by about 5psi. Not a lot, but something had changed. This took me back to the Goodwood trackday 18months ago where I managed to get down to sub 10psi flat out, approx 6000rpm. There the oil had got very hot and thinned. After that I dropped the sump, and measured the crank. All was good, so new trimetal bearings were fitted. Also an oil cooler/thermostat and VR1. It has been mentioned that the conrod may have been ovaled by the experience. So this time when the bearing started getting vocal at the prodrive track, I hoped that I had stopped soon enough as I still had 50psi pressure (this maintained until the last few miles on the motorway)

However, I fully expected the issue to be no4 again. But very wrong to assume, this time it was no2. So it wasn't tje conrod, or even crank wear that caused the issues directly, it appears to be the bearings not coping with having a moderately hard life?

Luckily the spare engine I bought a few years ago as part of a "job lot" appears to have been honestly described. having popped the sump off and checked the bearings they all appear new, not sure if it is a fresh grind but certainly looks it. So the car will return to the road soon. Those new bearings are all  AE, not certain if that is good or not :-/

But, as mentioned above, anybody else had similar experiences? And yes, I know a 1500 doesn't like to live near the red line, so I will try to be more careful in the future. This engine needs to give me a year I reckon.....

[oil_on_the_carpet]

These 1500 engines were never durable. A brisk run down the M4 back in the 70's did for the old mans then almost new Dolomite 1500 engine, and that was on a car only a year old.
The 1300 was always a far more durable engine.

AE bearings are fine, there is a lot of nonsense spouted about alu/tin etc bearings, but as long as the clearances are OK and the oil is sound, they work perfectly well for 99% of applications.

[ferny]

cliftyhanger wrote:

But, as mentioned above, anybody else had similar experiences? And yes, I know a 1500 doesn't like to live near the red line, so I will try to be more careful in the future. This engine needs to give me a year I reckon.....

Yes, but not on the track and not just 1500 engines.  :B


Is it possibly you've got yourself some oil starvation from enthusiasm on the bends and it's caused one bearing to pick up just enough for its life to shorten significantly? Sump baffle time?

[Nick Jones]

I used to have problems with bearings in 1500s in my Herald.  Getting the crank properly ground so that the journals were actually round and fitting an oil cooler (with thermostat) apparently solved the problem.

Nick

[nang]

I wouldn't be fitting new shells in anything without using a micrometer to check the shaft journals first. Anything more than 1/2 thou and I'd be gettind the shaft ground  AND checked after the regrind. I'm afraid all engine reconditioners are not created  equal.  :(
Tony.

[69vitesse]

By modern standards, the amount of oil per litre capacity in the old Triumph pushrod engines is inadequate.
My Honda runs with nearly twice the quantity of oil, and an oil cooler is std.

Even driven 'politely' back in the day, like many of its contemporaries, the 1500 could expect to be reconditioned around 40k with new shells and a grind.
Drive them in any spirited fashion and you can't expect them to last. And these days, the average speeds at which we drive is far higher than back in the day.

Nangs point about the grinds well observed, standards have defo slipped. Badly ground corner radii, taper and variations in diameter can all be expected in grinds from anything other the the few remaining high end shops.

[Clive]

Turns out the TH5 cam in the engine was knackered on a couple of lobes too. The profile had just started to go, but the surfaces were crazed. About to expire bigtime I reckon.

On the plus side, the unkown engine was investigated. It seems to be unused since a fresh regrind and new AE bearings. Managed to increase one of the thrusts as std ones were fitted (but again new)

Credit to Paddocks for getting the gaskets etc to me on time. In fact the package arrived just as we were ready to put th ethrusts back in.

Off now to slip the engine back in the car..........
BTW anybody got a set of std needles for a 1500???

[Tim Bancroft]

A few CT Stalwarts have had success with 1500 engines, Dale Barker and Dave Pearson.

Might be worth contacting them to discuss their thoughts-e-mails would be better.

[Clive]

Tim, it is the last Triumph engine going in the car.
It runs a treat, and as I have just filled it with cheapo oil (checking for leaks, but as it all appears new, will let it run for a couple of hundred miles) it still gets well over 60psi oil pressure at 2000rpm even after being run on the drive for 25 minutes. Need to get some std needles in the carbs, tune and in a few days drop in the millers css 20w60 oil I picked up at stoneleigh.
Lucy has instructions on how to prevent me going over 5000rpm too :-/ I need to keep it going until next year. The autosolo will be interesting...........

[Mark Hammond]

I can remember selling both 1500 Dolomites and Spitfires new back in the 70's and early 80's and engines being replaced under warranty.  Not uncommon.  30 odd years later things won't improve!

M.