Brielle Cosworth Venturi LM600 works piston

3 litre twin turbo 24v 600hp Venturi LeMans engine.....

Three high res shots below (linked rather than embedded because they're 2048 x 1536)

Shown with a standard NA Laguna/Safrane piston for reference. The main height difference is caused by the additional skirt on the NA piston, but the pin diameter and rod length were kept standard (even though the rods themselves were fairly obviously not!)

No, I'm not trying to build a 600hp DeLorean engine

http://www.delorean.co.uk/pics/DSCN2708.JPG
http://www.delorean.co.uk/pics/DSCN2709.JPG
http://www.delorean.co.uk/pics/DSCN2710.JPG

I take it you have bought a set Martin?

How much???

Nope, I haven't bought a set. I have one piston in my hot little hand which I'm taking care of on pain of death, and will be having a set made using it as a template. The cost should come in at around a grand for the six including rings and pins, CNC machined from forged slugs. My aims are modest compared to you guys - I'd like to get close to the 300hp mark but I'm trying to do a setup that can be duplicated to a budget rather than an all-singing, all-dancing rocketship that'd make a DeLorean thoroughly dangerous. So why not just copy an A610 piston? Well, given the choice, and the same price, you may as well go with the best

That might be a 610 or 400GT piston. 600LM ran forged pistons, and pocketed, that one in the picture is cast.

It's an LM600 piston from an LM600 engine.

For me, specs change, perhaps they did not build according to the spec. Then again, perhaps this 600 has been rebuilt in the past with non-OEM parts, equivalents being deemed satisfactory as alternatives ??? I guess no one knows unless they really have an exact history of the motor???

Anyway, look forward to seeing a super-quick Delorean, without making any comparisons to the quick Renaults.

Well it's definitely not a Renault piston. Ignoring the integrity of the source of this piston, the width of the oil scraper seal puts that to bed, and AFAIK the Venturi 400 engines were A610 engines with 24v heads.

Cosworth make their own 93mm pistons and this is definitely cut from a 93mm forged blank, hence the "unfinished" finish. FWIW the NA cast Renault pistons have a machined finish...

The gudgeon pin is located differently and is of a different diameter and internally the machine marks suggest the PRV rod is fatter than the Cosworth one on which it is based.

This piston is quite a bit lower than the standard NA - more than enough to exclude the need for the OEM 12v pockets, and there's plenty of meat to be able to add pockets if they were required.

You don't need (or want) to copy an 'unknown' piston. Just take measurements with the standard N/A piston, and then work out what volume you need to remove from the head height to get the desired compression ratio as you don't know what compression ratio that piston is.. LM's ran 7.3:1 (and lower) but on a 24v head but this has a different combustion chamber volume to the 12v...

Also, who told you the pistons in the LMs are 'Cosworth'? All the LM tuning and preperation was designed by EIA, the French company that developed all the Venturi engines and the late Alpine Centre 2.8 Turbo, who own the famous preparation company Ferry Developments, which I use for some parts. By a not too strange coincedence, they have all the forged pistons, rods, cams, heads, turbo's, 3.2 forged crank etc listed for the GT, 400 Trophy, 500 & 600 LMs in my catalogue.

Can you tell me what this is please Dave

Can you tell me what this is please Dave

It's like the Terminator in T2 getting shot!!

Ja !

' Phase-plasma rifle in za forty-vot range '

"bonking" toy for Robocop...

Ja !

' Phase-plasma rifle in za forty-vot range '

Only what you see buddy!

Classic line

You don't need (or want) to copy an 'unknown' piston.

I'm not sure how much clearer I need to be on this - it's a genuine LM600 piston from bona fide LM600 engine, lent to me by the owner *of the engine* (and several others!). He says (and he'd know) that it was made by Cosworth.

I'm just the messenger and am extremely grateful to be able to borrow this piston.

I've done the maths on the CR based on my measurements and everything is spot on for my needs.

I did try and get pistons from you, Dave......