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Rich B · Posted: Sun Nov 30, 2008 7:38 pm Post subject: Forged pistons

Hi Folks

My forged pistons have just arrived from the USA, thought I'd post a piccy:

They're made by JE and are 89mm, hopefully this gives a new capacity of 1800cc. These will be combined with gas flowed heads and billet fast road cams (photos to follow). Should be quite quick I hope....

Admin · Posted: Mon Dec 01, 2008 2:23 pm Post subject:

Hi

Forged pistons. Ebay rip off. Should have got some genuine real pistons Wink

.

Look good. Keeping compression about stock?

All the best

Keith
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Rich B · Posted: Mon Dec 08, 2008 9:07 pm Post subject:

Compression ratio will be raised slightly I think but the calculations to work it out are rather complex so I couldn't give you an accurate figure.

I'll be using flowed heads and billet fast road cams and anticipate power to be around 175bhp....

rsfruitbat · Posted: Wed Dec 10, 2008 8:20 am Post subject:

Hi Rich b
Can you tell me what ratio you are after and :
if you have had any work done on the head chamber
or them skimmed
or block skimmed.

Ideally if you can tell me the head cc's JE should be able to tell you the piston top cc's and I can calculate it for you.
Did a lot of this when I was building the 1400.

rsfruitbat
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Rich B · Posted: Wed Dec 10, 2008 8:25 am Post subject:

Hi

Thanks for that. I'm not really looking for any specific CR, all I know is it will be raised slightly. Heads have not been skimmed as far as I know, nor has the block. The pistons are standard shape just larger (89mm) and are made from JE's 89m casting.

Cheers

Rich

rsfruitbat · Posted: Thu Dec 11, 2008 2:30 pm Post subject:

If you dont skim anything then CR will go fro 10:1 to 10.4:1
If you need to skim heads then every .1mm you skim will reduce head cc by approx 0.4cc. At least initially every 0.1mm you skim CR goes up by 0.1. Skimming block will have slightly more effect.

rsfruitbat
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Rich B · Posted: Sat Dec 13, 2008 11:57 am Post subject:

Thats very interesting, thanks for that. I'm a bit cautious of skimming block or heads as I don't know how much tolerance there is between the valves and the pistons at the moment. I bought the heads from Dave Barbara who paid over £2500 for them, I don't know if they have been skimmed or not but I would imagine for that kind of money, a proper job would have been done.

I'm hoping all these mods will give a decent power increase although when you look at it the increase in capacity is only about 88cc. I wanted everything to run ok on the standard (albeit superchipped) ECU so I thought the 89mm pistons would be about right. I'll sort out a programmable ECU at a later date. I think you need to know where to draw the line thoug, you can get to the stage where you could have bought a decent fast car instead!