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89Mm Crank

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What you actually need to take into account with any build is the incidental increase in cost for an item. To say an LCR modified RB crank costs $2700 is correct but the true cost is the biffetence between this price and the other option. In most cases this is reconditioning an old crank. By the time it's crack tested polished balanced checked for alignment etc etc (properly) the price difference to the RB option is probably not as much as it seems. Remembering also that you get a new crank. Another of the advantages of the 89mm option is the availability of very well priced high quality rods that retain a big end journal size that is robust.

But each to their own.

 

Not only that but the cost of all supporting components and machining required to fit such a radical crank...

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Not only that but the cost of all supporting components and machining required to fit such a radical crank...

Actually very little machining required. Nothing that a grinder in the correct location would not fix.

The cost of (new) 6 forged pistons and 6 rods is much the same for a std build. That's the advantage of this option, the rods are commercially available and very reasonably priced. They come from a standard modern day high revving production engine that will rev easily past 7.5K.

On the surface it seems quite complicated and the perception is its expensive but its actually not.

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Not only that but the cost of all supporting components and machining required to fit such a radical crank...

Actually very little machining required. Nothing that a grinder in the correct location would not fix.

The cost of (new) 6 forged pistons and 6 rods is much the same for a std build. That's the advantage of this option, the rods are commercially available and very reasonably priced. They come from a standard modern day high revving production engine that will rev easily past 7.5K.

On the surface it seems quite complicated and the perception is its expensive but its actually not.

post-103565-0-95489700-1453868663_thumb.jpg

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What are peoples thoughts on using a matching number L24 for a stroker build, use another motor and store the matching numbers away?

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If someone who has done this is willing to share what is a rough cost including labour and all that

Of a block with said RB crank ?

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Personally, your car you can do what you want with it.

 

In terms of best bang for your buck, probably better off starting with an L28 to go as big as possible, if you can find one, and also depending on what you want to use the motor for.

 

If you just want to give the L24 a tickle and a bit more poke, why bother with the stroker when a standard crank in a L24 will be a nice lively little jigger, especially if the bottom end is in good condition and doesn't need any work. 

 

No point spending money you don't need to.

 

With two motors that I am getting built at the moment, an SR20 tractor and an old 265 Hemi, they are very different approaches.

 

The 4 cylinder tractor will have new crank, rods pistons and all the other good gear as it is being built for racing, so reliability in a high stress environment is needed. 

 

The old Hemi, standard crank, just new pistons and rods to suit the rebore as the motor will be a nice torquey cruiser that will spend most of its life at about 3500rpm with the occaisional squirt or run upto 6000rpm. Other little things will be done to Hemi to increase reliability, but this needs to be done with any Hemi rebuild to address some very big weaknesses in the motors.

 

One build will be about double the cost of the other by the time everything is done to be able to bolt the engines into the cars, but that is due to the very different requirements of the motors.

 

Or, if you looked at Jason's engine in his 280Z Group Sc car and my old 2B Marque Sports car, power was similar, costs were very different, with very different approaches to building and the end uses for the engines. Jason's car is run in a very tightly controlled class and he used a lot more revs than my car did that ran in a category with a huge amount of freedoms in comparison. Mine was built to be a big lazy truck motor with a wide torque band to make the most of the greater freedoms I had under the rules. I could run slicks and bigger brakes so could use a higher corner speed to keep momentum going to get my lap times, where as Jason had little skinny wheels with R type tyres and restrictions on brakes, so his times were gained through a much more developed motor than what I had.

Edited by PZG302

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Long/bg stroke = lazy truck motor.

Ie torque mnster.

A short stroke (79mm) with very lng rods, and "short" bggish bre pistons = fast response RPM demon.

 

Two totally different ways to get a good result.

If you study the diagram, and comprehend Rod length to crank stroke ratios, the resultant answer will indcate at where in the RPM scale, peak power will be generated, anything above that is pure in-effcency, e, change up a gear

post-101049-0-20732700-1453875697_thumb.jpeg

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What are peoples thoughts on using a matching number L24 for a stroker build, use another motor and store the matching numbers away?

CBRJeff is doing just that Mark - Les is building his matching numbers L24 into a 3ltr ;)

I was about to build something similar with mine, but Les had other idea's...

 

If someone who has done this is willing to share what is a rough cost including labour and all that

Of a block with said RB crank ?

Minus induction, around $22k to $23k depending on options.

 

Ask me how I know... :(

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Actually very little machining required. Nothing that a grinder in the correct location would not fix.

The cost of (new) 6 forged pistons and 6 rods is much the same for a std build. That's the advantage of this option, the rods are commercially available and very reasonably priced. They come from a standard modern day high revving production engine that will rev easily past 7.5K.

On the surface it seems quite complicated and the perception is its expensive but its actually not.

OK, yes just fitting the crank isn't that much more and it's a no brainer in my point of view to do that instead of a V07 as the costs are similar. But 50mm carbs, bigger exhaust, bigger intake manifold, billet flywheel all that stuff that goes with it to really take advantage of it. 

 

 

What are peoples thoughts on using a matching number L24 for a stroker build, use another motor and store the matching numbers away?

This is what I did.

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CBRJeff is doing just that Mark - Les is building his matching numbers L24 into a 3ltr ;)

I was about to build something similar with mine, but Les had other idea's...

 

Minus induction, around $22k to $23k depending on options.

 

Ask me how I know... :(

 

So that's a complete motor with cylinder head, extractors, sump etc. All you need then is 50mm carbs or injection, say +5k for a drop in engine?

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So that's a complete motor with cylinder head, extractors, sump etc. All you need then is 50mm carbs or injection, say +5k for a drop in engine?

Correct G-Man.

I bet it makes your new engine seem cheap?!

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It makes me feel cheap! 

 

Looking at the green hornet videos the engine performance is on a different planet to all other L6 engines.  

 

And I bet the plug wires would be in the correct order ;D

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So that's a complete motor with cylinder head, extractors, sump etc. All you need then is 50mm carbs or injection, say +5k for a drop in engine?

 

Mine was a lot more than that by the time it got to my door... and the Green Hornet is a step up from mine. Don't forget engine dyno time and all the other little extras that go into it. Plus then you will instantly destroy your stock gearbox and then you need to upgrade your tail shaft, UNIs diff etc, etc. I thought that the stock gearbox would be ok for a bit, but when I say destroy i mean the engine literally destroyed it in basically 10 outings, none of which were in the hills or at a race track and more like test and tune trips around the streets to iron out the bugs. Les said the box would have suffered catastrophic failure at any minute if I had kept driving it and the internals were completely unservicable when i sent it down for exchange.

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Thanks for reminding me of why I am building a stock L24. That's the rub isn't it? Change 1 part you gotta change another and another and another and the list goes on.

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You will see a full Subi R180 4.4 LSD setup, stub axles, reco half shafts, mustache bar etc for sale shortly for this reason...  :

Edited by d3c0y

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