Are these pistons any good?

[Kevin (Mr T)]

http://www.ebay.co.uk/itm/FORD-1300-X-FLOW-PISTONS-090-x-4-711M-CROSSFLOW-87-780617-00-/381723954136?hash=item58e0854bd8:g:ERAAAOSwnH1WZZyY

[Thrustyjust]

Never heard of them. They will be cast pistons, which is always the crossflows weak spot. Although expensive in the first place , depending on what HP you are aiming at, but anything above 130 bhp to keep reliability, aim for forged ones, like accralite or arias .

[tisme]

I've mixed feelings about Trechii (some good parts, some dubious far east ) - these appear to be from Federal Mogul  http://www.federalmogulmp.com/en-GB/Brands/Nural/Pages/home.aspx

 

A few searches say they are (were?) made in Germany so I suspect they're going to be fine for a standard engine - Accralite or Omega (they own Accralite now) are probably the best and certainly for a tuned engine but they're not cheep (approx £100 a piston)   

[Geoff101]

Mine runs old Hepolite +90 1300 pistons in a 1600 engine which look similar. Once made 140bhp according to the build sheet and was at about 120 last time I had it dynoed. They need running quite cool though, 74 degree thermostat in mine. 

[Thrustyjust]

Hepolite cast pistons will make power, but they wont last as long as a forged piston. Crossflow pistons are very heavy and can crack in the ring lands. Its just the way they are with heavy crowns.

See here with a forged piston with machined crown. 

http://www.burtonpower.com/accralite-forged-piston-85mm-ford-x-flow-1-6-ohv-kent-fp115-85s.html

 

In comparison from using the 1300 cc cast piston, with the smaller bowl to increase compression ratio.

 

http://www.burtonpower.com/nural-piston-ford-1-3-x-flow-ohv-kent-711m-0-020-18647-020.html

 

Yes, there is a £400 price difference. But, if you use a high lift cam, with cast pistons, without measuring, usually a 234 Kent will 'just' have crown clearance , then you will have to pay a machine shop to machine slots for valve clearance, the forged you wont have to. So thats another £60 to £80 for that. You will have to get them balanced too, which you can do yourself, if you have some drug scales or pay a shop £30 for this. Still a bit of a price gap, but the cast pistons are designed for 75 bhp, not 130 bhp plus. They are the limiting factor of the crossflow bottom end, as the rods, crank and block are bullet proof. 

[Kevin (Mr T)]

Thank you all, think thay answers the question!