cranks

[cozzy]

Hi i have a spare early 97 4.2 engine in the garage and am looking to rebuild it.
does anyone know where i might be able to get a later crank as i know these are prone to snapping. cheers Mike

[Gazzab]

TVR Power, APM......

[The AJP Griff]

This came up on a thread on here,recently.I think it was suggested that you could have a billet steel one made for maybe even less money than what the original TVR ones cost?

[shpub]

When I looked into it a couple of years ago, it worked out at around £2k for the crank and bits to go with it. Prompted the LS transplant...

[Boosted LS1]

Out of interest what is it that causes the cranks to fail? Is it rpm's, lack of journal overlap, vibration?

[jammy_basturd]

From what I've read on here its porous castings.

[clive f]

I`ve done a bit of research on this myself recently and after chatting to a few people and in particular Andy from APM, the billet cranks, as far as I can make out, were originally made for the tuscan race cars, these are now rarer than hens teeth, the early 4.2 cranks were cast, and had problems( weak castings), the later ones being forged and are okay.
apparently one way to tell if you do have an early crank is to see where your sump drain is located, on the side and its the later crank, and on the bottom face and its the early crank.

racing green are selling crankshafts fro the 4.2 with the 2.3" journals
http://www.thetvrshop.com/TVR/Parts/Cerbera%20V8/c...

[shpub]

clive f said:

apparently one way to tell if you do have an early crank is to see where your sump drain is located, on the side and its the later crank, and on the bottom face and its the early crank.

Not actually that reliable. My first AJP had the side sump and the crank broke in the three places. I have seen several other similar engines with side sump and broken cranks. There really is not a reliable way apart from stripping the engine...

[Boosted LS1]

jammy_basturd said:

From what I've read on here its porous castings.

I'd be surprised if it was that unless they were being cast from monkey metal whatever that is I'd suspect that's it's stress related ie rpm's but have no real ideas myself.

[clive f]

shpub said:

clive f said:

apparently one way to tell if you do have an early crank is to see where your sump drain is located, on the side and its the later crank, and on the bottom face and its the early crank.

Not actually that reliable. My first AJP had the side sump and the crank broke in the three places. I have seen several other similar engines with side sump and broken cranks. There really is not a reliable way apart from stripping the engine...

thanks steve, my mind was settled, now I`m worried yet again!

[ridds]

Boosted LS1 said:

jammy_basturd said:

From what I've read on here its porous castings.

I'd be surprised if it was that unless they were being cast from monkey metal whatever that is I'd suspect that's it's stress related ie rpm's but have no real ideas myself.

They were I think. Cheap tat from China. One guy on here had his break in 7 places when the thing was idling!

[Boosted LS1]

^ Dear oh dear, that's awful!

[The AJP Griff]

clive f said:

shpub said:

clive f said:

apparently one way to tell if you do have an early crank is to see where your sump drain is located, on the side and its the later crank, and on the bottom face and its the early crank.

Not actually that reliable. My first AJP had the side sump and the crank broke in the three places. I have seen several other similar engines with side sump and broken cranks. There really is not a reliable way apart from stripping the engine...

thanks steve, my mind was settled, now I`m worried yet again!

Surely there should be a way of identifying which type of crank you have.The appearance of cast/billet/forged is going to be different??I've made many castings,and a piece of billet looks completely different.
I think you'll still have the problem of separating the good from bad castings though,unless you can find out how the casting was changed,perhaps visually different at web/journal or something?

ETA Clive,i've just found out that David Ike lives on the Island!Perhaps he could look into the future for you

Edited by The AJP Griff on Friday 7th November 10:53

[clive f]

I`ll tell you a story about him one day mate he was my next door nieghbour for a short while

[The AJP Griff]

clive f said:

I`ll tell you a story about him one day mate he was my next door nieghbour for a short while

x10!!!! So it was you that 'turned' him?

Edited by The AJP Griff on Friday 7th November 13:27