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mick260

Stroker?

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Hi. I am a bit of a novice. I have just bought an engine advertised as a stroker. I took the gamble and bought it because it came with a few other spares and it wasn't that expensive. So my dilemma is.

I measured the Stroke through the spark plug hole and it measured 84mm. With the research I have done it is around what it should be to be a stroker. My issue is I took the sump off today and the crank is stamped with P30. Which I have read is stock. Can a crank be modified for a different stroke or is it just a stock bottom end.

Thanks Mick.

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P30 is stamped on production cranks - look for V0740 cast into it to confirm it's a LD28 crank.
Look here to determine what you have: http://www.viczcar.com/forum/topic/7281-l6-crankshaft-id/

What sort of con-rods has it got in it? Custom items?
The reason I ask, is that a standard stroke crank can be offset ground to increase it's stroke, but it would need different con-rods.

Edited by Lurch ™

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Hi. Thanks. The crank also has P3040 stamped on the other end. How can I tell if they are custom conrods.

Mick

 

So that's a standard L28 crankshaft.

 

I'm betting you've bought an engine with a standard L28 crank & you've measured the stroke incorrectly (which is easy to do).

Can you take a photo of the con-rods just to make sure?

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Hi. Thanks. The crank also has P3040 stamped on the other end. How can I tell if they are custom conrods.

Mick

Hi

 

Measure the internal size of the bigends and post that number.

 

Cheers

 

PB

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Hi

 

Measure the internal size of the bigends and post that number.

 

Cheers

 

PB

Hi. I am guessing they would have to be removed for this. I wasn't planning on it. Was just going to do new seals and and put it in.

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Hi. I am guessing they would have to be removed for this. I wasn't planning on it. Was just going to do new seals and and put it in.

Hi

 

Not necessarily, you could just remove the big end bearing cap and measure.

 

Cheers

 

PB

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Hi

 

Not necessarily, you could just remove the big end bearing cap and measure.

 

Cheers

 

PB

Thanks for your help. I will have a look tomorrow arvo.

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if you have the sump off you can measure the stroke, just measure on the bottom of the piston skirt at tdc and then again at 180°
 

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Like a lot of "strokers" if it has standard crank the it would most likely have the longer rods with suitable pistons. Also check the bore if you can as well.

 

Also don't overthinkthings when trying to get measurements, use the KISS pricniple

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It is not at all difficult to stroke a stock L28 crank, and retain standardish journal sizes, with spray welding and grinding.

It will have needed shorter height pistons fitted to compensate.

Ignore the casting marks, and measure piston mvement.

Shoving a bit of stick into spark plug hole isn't accurate, due to angularity from the vertical.

Needs a bit of Pthagorus's theory to calculate the "rough" 84mm as the hypotenuse, to bring it back to an approximate verical.

That angle is about 18-22 degrees.

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I have actually contacted the shop that apparently did the build. Hopefully they will get back to me shortly. He thinks they should have a record of what work was carried out. I am pulling the head off on Friday so I can be ready to out my new head on it. That should take out the guess work of measuring the stroke. Thanks for all the input.

Mick.

Edited by mick260

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Mick, measure the bore as well as the stroke to determine the actual displacement. Also take some photos of the piston tops if you want, and we may be able to help you ID what pistons it has based on the bore and stroke combination.  

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So. Does anyone want to buy a stock l28 n42 block? I removed the head today to discover 79mm stroke and 86mm bore. Which I am to believe is standard. The Pistons look the same as my other l28. Ahh well. It was worth the punt. I still got a spare 5 speed and a wolf 3d comp for my other car. Thanks for all the the advice/help.

Mick.

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