broken Crankshaft

Posted: Thu May 08, 2008 8:51 pm Post subject: broken Crankshaft

Hello ,
A friend of mine broke his crankshaft on a 4AGE . He has a 3 ribs block , and small journals.
He was told that it was a common failure .....

It's a rally car , he doesn't want to have the same bad adventure .

Here's the question : will a big journals crankshaft fit his 3 ribs block .
He will have to change rods to fit journals , but will these big rods fit the forged pistons he have ? Or does he have to change pistons too?

Are the main crankshaft bearing same on both parts ?

and the last one : does somebody has the Toyota part number for the big crankshaft. He asked his local dealer , but he only have the EPC , are there are no measurment on crankshaft

Do you have any replacement suggestion HKS Toda or else ?
I'v added a pic of his car , he's a spectacular rallye driver as you can see
(162HP weber 45 dcoe powered )

any help welcome
Regards
Filh

Posted: Thu May 08, 2008 9:00 pm Post subject:

In french

Malheureusement pour lui il doit changer tout le bas moteur (bloc/vilbrequin/bielle/piston) pour celui d'un redtop, car rien n'est compatible...

Posted: Thu May 08, 2008 9:52 pm Post subject:

13401-16020

Posted: Thu May 08, 2008 10:17 pm Post subject:

thanks for the part number .
in french :
<<<<D"après les infos que j'ai les paliers de vilebrequins sont les mêmes , seuls mes diamètres de maneton changent .
J'attends la suite<<<

Still waiting your further informations : will he have to change block and pistons, to have the big journals crankshaft ? (It's what he wants to have)
Filh

Posted: Thu May 08, 2008 10:19 pm Post subject:

Both axles have same main bearing size (48mm) and it fits straight in to 3 rib block.

What size piston pins he have? 18mm? 19mm? 20mm?
Most 42mm conrods have 20mm piston pin. I don´t think that there is a conrods that have 42mm lower hole and 18mm piston pin.

In here are many over 200hp 4A-GE rally engines and almoust all uses original (but balanced) 4A-GE 42mm cranshaft, including me.

Posted: Fri May 09, 2008 7:34 am Post subject:

The problem isn't uncommon. Did he balance everything properly?

Takumi Joined: 30 Mar 2008 Posts: 205

Tell him to get a billet Formula Atlantic one and call it a day. I have one if he's interested.

F0b

Posted: Sat May 10, 2008 7:17 pm Post subject:

Big crank will fit, requires big conrods and pistons.

Hi-rev requires precision balancing.

Posted: Mon May 12, 2008 10:24 am Post subject:

Posted: Mon May 12, 2008 11:23 am Post subject:

Posted: Mon May 12, 2008 10:43 pm Post subject:

Thanks all for your answer .
I got a price (don't know the brand ) for a forged crankshaft with conrods :
about 3500€.
He actually have a balanced one with small bearing , and small axles .
He would like to fit the 42mm crankshaft into his newly rebuild 3 ribs block .
BAD DOG gave me the part number for crankshaft :13401-16020 .
He wants to buy new parts , but want also to know if they will fit , before buying
And I just saw the broken part today : it's broken near the 4th cylinder journal . Conrods , bearings and block are well in health.
Filh

Posted: Tue May 13, 2008 8:41 am Post subject:

new OEM crank from toyota should be sth like 800euros. (forged)

New pauter rods - sth like 800 USD + shipping. (billet)

That's less than 3500euros IMHO!!!

Posted: Thu May 15, 2008 2:56 am Post subject:

my friend has another question : about flywheel : on a 42mm crankshaft, are flywheel fixations same as on the small one.I think the number of bolts aren't the same , and flywheel is larger ?
Filh

Takumi Joined: 30 Mar 2008 Posts: 205

Good luck man! But get the 20mm crank if you can.

Posted: Thu May 15, 2008 10:41 am Post subject:

Posted: Fri May 16, 2008 6:21 am Post subject:

I'm currently having Loynings Engine Service(winning formula atlantic engine builder) build me a bottom end. I'm using the smaller crank because it is SUBSTANTIALLY lighhter....

What is common is if it isn't properly balanced the journals marked begin an oscillation because they are not the same as the counter weight on the other side of the journal. This oscillation can be eliminated with balance, and hardening(shotpeen the crank

Using a newer block that is a bit stouter never hurts either

early block on the bottom(upsidedown), later block on top

Posted: Fri May 16, 2008 10:21 am Post subject:

Weight difference is ~1 kg.