AJP8 steel billet crankshaft(s)

[Thom]

Hello,

I have searched through older posts but have not quite been able to find if aftermarket billet steel crankshafts are available for both main bearing sizes, ie early 4.2 (small) vs late 4.2/4.5 (large) ?

Thanks

[Jhonno]

Have you spoken to Powers? They manufacture them, or have then manufactured for them I should say.

[Thom]

Had noticed they supplied new billet crankshafts, but I have not asked them directly about the bearing sizes as I thought the PH Cerb collective would be knowledgeable enough to answer this relatively basic question.
It could be that anyone who may be looking into purchasing an early 4.2 on its original, unrebuilt engine would benefit from this information...

[Tanguero]

Thom said:

Had noticed they supplied new billet crankshafts, but I have not asked them directly about the bearing sizes as I thought the PH Cerb collective would be knowledgeable enough to answer this relatively basic question.

As they have them made for them, who knows what they may or may not decide to have made next.
My small journal 4.2 had to be replaced with a large journal crank as part of the 4.7 upgrade and at the time there were availability issues around billet cranks in any size.

[Thom]

Tanguero said:

My small journal 4.2 had to be replaced with a large journal crank as part of the 4.7 upgrade and at the time there were availability issues around billet cranks in any size.

So you had your block and main caps machined to suit larger journals?

[Tanguero]

Thom said:

Tanguero said:

My small journal 4.2 had to be replaced with a large journal crank as part of the 4.7 upgrade and at the time there were availability issues around billet cranks in any size.

So you had your block and main caps machined to suit larger journals?

Yes, the 4.7 runs on a large journal billet crank.

I have a spare small journal crank in perfect condition...

[gruffalo]

And I have a large journal one if required.

[Ardmedden]

Hi All. I'm new to this forum although I've had an early Cerbera for a couple of years. I bought it will a snapped crank and a few other bits needing attention.
I have various spare engine parts so I might be able to help other people out but I'm short of a crank for my rebuild.
I would be interest in hearing from anyone who has one they would sell.
Cheers Simon

[Tanguero]

Ardmedden said:

Hi All. I'm new to this forum although I've had an early Cerbera for a couple of years. I bought it will a snapped crank and a few other bits needing attention.
I have various spare engine parts so I might be able to help other people out but I'm short of a crank for my rebuild.
I would be interest in hearing from anyone who has one they would sell.
Cheers Simon

What size journal do you need?

[Chuggaboom]

So just to clarify for the less well knowledgeable on the AJP front, if you have an old 4.2 with the smaller bearing size, it is not possible to fit a later larger bearing crank to the block because the journal size is that much larger than can be accounted for in bearing shell thickness ? Therfore an older block/bearing caps have to be line bored out to the later 4.5 block/crank journal size ?

[Ardmedden]

Yep, based on the checking I've done the early 2.3" journal blocks and main bearing caps can be easily line bored to accept the later 2.5". The big end bearings are the same at 2".
For road and track day use the cast crank with the correct counter balance design is good enough whereas for heavy track use a steel billet version is preferred. Either is fine for my needs.
Therefore the main thing I'm looking for is a crank with the correct counter balances and I can have one of my 4.2 blocks line bored.

[Tanguero]

Ardmedden said:

Yep, based on the checking I've done the early 2.3" journal blocks and main bearing caps can be easily line bored to accept the later 2.5". The big end bearings are the same at 2".
For road and track day use the cast crank with the correct counter balance design is good enough whereas for heavy track use a steel billet version is preferred. Either is fine for my needs.
Therefore the main thing I'm looking for is a crank with the correct counter balances and I can have one of my 4.2 blocks line bored.

I still have a small journal 4.2 crank available if you are interested, also a set of 4.2 pistons. All in excellent condition.

Edited by Tanguero on Saturday 31st December 15:29

[FarmyardPants]

I thought AJP (flat) cranks didn't have counter balances?

[Tanguero]

FarmyardPants said:

I thought AJP (flat) cranks didn't have counter balances?

[from PowersPerformance website]

[FarmyardPants]

Furry muff

[Chimp871]

Ardmedden said:

Yep, based on the checking I've done the early 2.3" journal blocks and main bearing caps can be easily line bored to accept the later 2.5". The big end bearings are the same at 2".
For road and track day use the cast crank with the correct counter balance design is good enough whereas for heavy track use a steel billet version is preferred. Either is fine for my needs.
Therefore the main thing I'm looking for is a crank with the correct counter balances and I can have one of my 4.2 blocks line bored.

As someone whose looking to buy a cerb and not too worried about getting an early 4.2 design with the possible weak crank, I'm curious to know if line boring an early 4.2 journals to the larger 2.5" is cost effective and relatively easy to do?

What else would need uprating going down the line boring route besides a new balanced crank (from powers)

[Jhonno]

Chimp871 said:

Ardmedden said:

Yep, based on the checking I've done the early 2.3" journal blocks and main bearing caps can be easily line bored to accept the later 2.5". The big end bearings are the same at 2".
For road and track day use the cast crank with the correct counter balance design is good enough whereas for heavy track use a steel billet version is preferred. Either is fine for my needs.
Therefore the main thing I'm looking for is a crank with the correct counter balances and I can have one of my 4.2 blocks line bored.

As someone whose looking to buy a cerb and not too worried about getting an early 4.2 design with the possible weak crank, I'm curious to know if line boring an early 4.2 journals to the larger 2.5" is cost effective and relatively easy to do?

What else would need uprating going down the line boring route besides a new balanced crank (from powers)

It can be done, but only use someone who has done them before imo..

In terms of uprating it depends, if you are just doing a standard build rods and pistons are the same and not a massive weak point. Aftermarket pistons/rods are available, and their main advantage is lighter weight.

[Chimp871]

Thanks. I would only use the major rework specialists.

Out of curiosity of they do sell a forged large journal balanced crank wouldn't the pistons & conrods need to balanced with the crank, or am I getting a bit OCD about it?

[Jhonno]

I would do it..