Big end

[gaz]

My TR is currently at one of the old TVR units been worked on by one of the ex TVR engineers. it had a grumble on the bottom end last September (bearing in mind this engine was rebuilt a few years ago and has less than 3000 miles since).

It's never been thrashed or been low on oil and has had 4 oil changes since rebuild oil pressure light always comes on with ignition and goes off straight away once running.
However upon investigation bearing number two is the culprit of the noise,
It's heavily scored on both sides an worn at the edges the crank is also scored in that area.
What would cause bearing failure so soon

www.classiccarrunblackpool.co.uk

1981 DHC 2.0 Litre
1980 DHC pedal car
1982 DHC TR-ailer in the making

[Cobber]

Sounds like V8 time! C'mon, ya know ya wanna! [:p]

"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

80'Triumph TR7, 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
'98 MG-F, 69'Ford F250.

[gaz]

It is something I am contemplating however this engine will be going back in for at least this year

www.classiccarrunblackpool.co.uk

1981 DHC 2.0 Litre
1980 DHC pedal car
1982 DHC TR-ailer in the making

[HDRider]

It could have been a bit of debris that was still in the crank oil ways when it was reassembled, bad clearance on that journal, a bent rod, out of round big end, restricted oil flow to that journal.

There are lots of thiings that can go wrong with an engine.

Edward Hamer
poertaluma CA

[Beans]

If only one bearing is affected there are a few options;
1. Affected bearing was fitted incorrectly;
2. Bearing cap fitted wrong way round;
3. Dimensions bearing/big end not matching;
4. Dirt in oil gallery;
5. Bolts torqued down incorrectly;
6. Something wrong with crank shaft.
Sure someone will come up with more options ...

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[Hasbeen]

I'd go with some swarf in the oil ways somewhere.

In 1964 I drove a Hillman Imp in the Bathurst 500, in the days when it was for stock standard cars. Rootes Australia gave us a new Imp with 8 miles on the clock, & it had 16 miles when I drove it home to prepare for the race.

I was pretty horrified when I saw the big end slippers. After just 16 miles they were deeply scored over a large area. Between a third & 2/5th of the bearing surface was gone by this scoring. This was deep & all big ends were effected.

Talking to a couple of others who prepared Imps, all had similar damage to the big ends. Out of interest we collected the swarf we got out of various components. The cam shaft produced half a large tea spoon full of filings.

This damage did not cause any noise from the engine, & many Imps that were probably just as bad, went on to run 100,000 miles before requiring rebuilds.

I would be looking deeper if it were my engine. A reduced surface area should not produce a rumble, provided the un-scored area is the right diameter. A rumble from a bearing should only occur if there is excessive clearance.

It is not unheard of for machinists to get one journal undersize when regrinding. It is also not unheard of for one slipper in a pack of 8 to be the wrong size. I had one mate who got one standard slipper in a set of 20 thou undersize. That produced more than a rumble.

I'd be having a good look, micrometer in hand, before the thing goes back together.

Hasbeen

[john 215]

Hi Gaz,

Ensure they are using good quality bearings, there are some very poor quality manufactured bearings out there. Agree with all the things Beans said but also ensure new big end bolts are fitted, something I have always done. Worth getting the con rod checked to actually circular any doubt would replace.

At very least check the oil pump for wear, always best to replace after a bearing failure.

Cheers John


LIVE LIFE A QUARTER OF A MILE AT A TIME!

1976 Speke FHC Beauty Now with an overdrive conversion

1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6, BUILT NOT BROUGHT !!!!

[FI Spyder]

County bearings should last 10,000 miles like they did on club members Dolomite Sprint. There are some supposedly better quality bearings out there. Three metal bearing are better than the cheap two metal bearings.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[gaz]

Cheers guys
I'm getting withdrawal symptoms now I've not driven a TR since July last year and this blue one since February 2013

www.classiccarrunblackpool.co.uk

1981 DHC 2.0 Litre
1980 DHC pedal car
1982 DHC TR-ailer in the making

[gaz]

**Update**

I went to Blackpool road and rally yesterday the engine is finished they have stripped the cylinder head and re skimmed and reset the tappets & checked the camshaft etc.
Replaced piston rings acid washed the head and block, replaced a damaged con rod, re ground the crank, replace big/little end bearings, new water pump, new oil pump & checked and washed everything else.

They reckon a combination of two things caused the damage:
Running too rich.
And the oil filter was fitted incorrectly, the paper eliment was floating around in the canister as something is missing from inside the canister.




www.classiccarrunblackpool.co.uk

1981 DHC 2.0 Litre
1980 DHC pedal car
1982 DHC TR-ailer in the making