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4age Pistons In 5k


tioklou

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  • 4 months later...
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Ok I know this is a few months old. But it's what I'm thinking of doing also. Does anyone know what cr the 4age pistons will be? Would getting raised comp pistons be able to get the cr to about 9:1? As that's what I'll be after. Also do the 4age rods fit straight onto the 5k crank if your saying to use them?

 

And page 13 here

 

http://www.bowdenengineparts.co.nz/pdf/pistons.pdf

 

has 4age pistons with 18mm gudgeoun pin ;)

 

Matt

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bluetop 4age's came with 18mm gudgeon, everything after came with 20mm gudgeons.

 

as far as turboing is concerned. if you want off the shelf forged pistons its very hard to get for bluetops. i think wiseco list them, but no one else i know of does them off the shelf.

 

iirc your better off using the 4age rods aswell. the redtop rods are reputed to handle 200+rwkw and 8000+rpm prepped properly, I'm pretty sure their longer than K rods aswell?

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So can anyone confirm that 4age rods and pistons will fit straight onto 5k crank? I'll be using spool rods when I get around to building a motor and want forged pistons to work with it.

 

Anyone have information on the compression ratio that comes up? And if the block needs maching. How much by?

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TRD ke70's Rally car ran this setup, I'm sure he'll post up more useful information when he spots this threads warm again. Pretty sure you need to shave 2mm off the block though, I did all the maths years ago, can't remember anymore. Get the ACL piston and bearing catalog and you'll be able to work out some of the key differences, not sure on the 4K rod length though.

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  • 3 weeks later...

I'll be installing a set of 4AGE pistons into a 5K in preperation for turbocharging... Will post a deck height measurement when they're in there...

 

I'm not going to be shaving anything, but can use the data to put into any of the online engine calculators to figure new compression ratio...

 

This is the one I'm using, but there are others that take into account gasket thickness and piston dish (or dome)...

Engine Calc.

 

Rough figures indicate a drop down to low 7s... meaning a decking of 3ish mm to bring it up to 9s again. That's not dealing with 100% accurate ccs or dished pistons.

 

Personally I'm using a 3KB head to bring compression up...

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well you could use the 18mm pin, but if your going to turbo the engine go for the 20mm pin with a 4AGE piston.

The rods(4AGE) fit straight onto the crank, but there is a lot of clearance between the side of the rod and crank, this looks to be a problem but it's not, as long as you have a good oil pump and good clearances(not loose) on the crank, our crank is also cross drilled to stop it loosing oil at hi RPM.

 

We have run this setup for 3 years now and it hasn't given a problem, also know of another guy running the same setup and he hasn't had any problems.

We had to machine 3mm off the top of the block to get the CR we wanted, if you were using hi compression pistons you may not have to do this.

But you'll need to dummy assemble the engine and CC it, as well as the head to get the exact CR.

 

hope this clears up some stuff.

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Cheers for that. I think it would have scared me a little to see so much room either side of the rod...

I'm trying to get away with not decking the block, so we'll see how that goes, and what CR it gives me. Again, a proper CC of both head and deck height will give me accurate figures to work with, so they'll all be getting posted here when I have them. Probably some pics of it all going together too...

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  • 2 years later...

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