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Ashley James

Bust Crankshaft?

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There's a horrible deep clonking coming from the bottom of my engine which I suspect is most likely to be a broken crank. Hopefully it'll be out tomorrow and I'll know for sure, but has anybody an engine or crank they could they could sell me?

 

I needed to get the box out because there was no syncro on third and the flywheel and clutch need balancing, so I'll rebuild it all now.

 

Ash

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Photo shows a 4A GB + OD running a leak/pressure test by backdriving with an electric motor. This followed complete strip/rebuild after 194000 miles.

 

Al.

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Hi Ash,

bad luck mate. I haven't a replacement for you but could you give us feedback on where the crank is broken.

Quite often it is at the #4 big-end journal/web interface. Possibly caused by machining marks

 

Roger

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Thanks Roger. I haven't got it out yet, but I don't think anything else would make a noise like this!

 

Engine has done 57,000 miles since Protek built it in 1987 and it was a good one. All I did was have new valve guides fitted and check cam chain bore wear and tappets, so it might just be old age. It all looked excellent.

 

I just hope It doesn't break the bank and that I can find a crank with a good life expectancy.

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Neil

 

I don't think I need to. There was a Corvette on our Estate a few weeks ago making a very similar noise, which turned out to be the crank.

 

Whatever it is needs the engine stripping because it's internal.

 

Ash

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Guest ntc

Ash

Worth a try remove the bang (ie load) fingers crossed for you

 

Ps

Seen a bent rod make an awful sound hitting the liner

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Hope it hasn't trashed the head as well - that's how I lost my beloved SAH Stage 3 head.

 

I do hope a few more people will call for re-manufacturing of 4-cylinder crankshafts at the SDF meeting at Malvern. Lack of usable cranks is a real threat to survival of early TRs as seriously usable cars (as opposed to posing pouches!).

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The crane is at work, so I may not get it out tomorrow, but as soon as I do I'll report back. It was up round 4000 rpm when it went, but I was less than a mile from home, so hopefully I've limited the damage.

 

When I removed the head, the bores were perfect, you could still see the hone marks, but it's been doing 250 mpp and I'm told that it has Hepolite Powermax pistons, which were notorious for burning oil, so I can re-ring it at the same time.

 

Hopefully if I can get a good crank it'll be a better engine than it was when I've finished and it was a beaut.

 

Ash

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Been there years ago with a broken crank....Mine started with a vibration on over run...it was flexing as the crack got worse until it broke.....and drove 12 miles home being broken.

 

One way that might tell you is...

 

Start the engine and then depress the clutch pedal. if the noise changes or goes away it's probably the crank......loose flywheel bolts can make some strange noises too.

 

The joys of TR motoring.

 

Perhaps we should start a broken crank club....I wonder how many members there would be.

 

Dick.

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Mine went on the motorway about 7 miles from home but I got there, although Lynda said she could hear the racket long before I reached the house. I had hoped as I limped home that it was just a loose clutch assembly or flywheel as the pedal was bouncing up and down quite violently.

 

In all honesty, the bottom end was long overdue a rebuild, so I wasn't too bothered about the pistons and liners. Unfortunately, the valves had been driven into the head and all the valve springs were broken.

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Ash, if you can't get a crank from TR sources, the Vanguard movement might be able to help. Not sure which model(Phase 3 or Vignale ?) but some later 4 pot Vanguards had suitable cross drilled cranks. The Sportsman had them of course, but they're scarce. Vanny experts will know.

 

Suggest checking the journals before purchasing a used crank - up to 20 thou off is usable, but 30 thou and above isn't ideal. Also suggest crack testing. Tiny starter cracks often can't be seen with the naked eye.

 

Viv.

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Guest Mick RichardsChange...

Ash,

 

Vivs comment ref crank useability are wise but I think know these crankshafts are ok up to -60 thou on the big ends. I won my last Register championship using one, mind you at the hp it was producing it was spreading the bearing material out sideways from the rod.

 

If under 20thou just make sure of the hardness or have nitrided, it will be fine. (ps stress relieve no 4 journal at same time (to help avoid breakage if you are doing this).

 

Mick Richards

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Thanks chaps, I will bear all in mind. Everyone on the forum and by PM has been fantastic. Yesterday I was very unhappy, but I'm far more optimistic today thanks to all the help and have the engine and gearbox (third synchro unhappy) ready to lift out. I even got the apron out without scratching it. I'm now undersealed better than the car, but at sixty six I'm a bloody sight older aand in worse nick! It's not going help and the wife gets very touchy if it gets on the sofa!

 

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Ash-

 

Well if you happen to have travel plans to the US, please drop me a note - bring a big suitcase as well. I have a few crankshafts stashed away!

 

Regards

Randy

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Hi Ash,

 

I have a spare one if turns out to be the worst. It has slight suface corrosion and no idea about its past, but it might be worth getting it checked out if you're stuck.

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Romek and everyone else I'm sorted thanks to a Register member, one of quite a few who offered. This is a hell of a good club and people's generosity has been overwhelming.

 

It is the crank, the engine is out and I'm about to pull the sump off to see where it has broken. Unexpectedly it appears to be the front half, so pray the crankcase has survived.

 

Does anyone know where I can buy the jobbies to hold the liners down while I re-ring it. There's no bore wear or anything but I'm told the forged Hepworth pistons mine has were notorious for burning oil. It's been doing 250 mpp.

 

I'll post photos once I'm inside.

 

Ash

 

PS. Romek my son has started my seats if you still want the TR3 ones I'm using now.

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Hi Ash,

to hold the liners in place why not use some short section of 22mm copper plumbers tubing. Some areas may need a penny washer etc.

 

Roger

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Romek and everyone else I'm sorted thanks to a Register member, one of quite a few who offered. This is a hell of a good club and people's generosity has been overwhelming.

 

It is the crank, the engine is out and I'm about to pull the sump off to see where it has broken. Unexpectedly it appears to be the front half, so pray the crankcase has survived.

 

Does anyone know where I can buy the jobbies to hold the liners down while I re-ring it. There's no bore wear or anything but I'm told the forged Hepworth pistons mine has were notorious for burning oil. It's been doing 250 mpp.

 

I'll post photos once I'm inside.

 

Ash

 

PS. Romek my son has started my seats if you still want the TR3 ones I'm using now.

 

 

Fingers crossed for minimal collateral damage.. I have not done this personally but I have seen people use some big washers with suitable bolts into the head stud holes to clamp the liners.

 

Stan

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Guest Mick RichardsChange...

Large washers with old piston gudgeon pins slid down the studs on top and then washer and stud nut to clamp down (15-20lbs of nip should be fine, mk 2 click made by mouth when tightening 1/2" socket drive) lol .

 

Keeps the area around the liner clear in case you are working around the block face, (removing replacing pistons etc).

 

Mick Richards

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I'll expect I can sort something out to keep the liners under control, but it's always nice with the right tools.

 

I have the head off now and can see that piston number one has come within a gnat's thingammy of hitting the head, but otherwise all seems well. Down below doesn't sound nice, but I've had enough for today and will continue tomorrow.

 

Ash

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