which pistons?

[ZL. 19]

So ive decided to build the fairlane a motor since i have an 86da block in another fairlane and a motor out of an xg that i will pull

the crank and rods out of,i plan to go carb and ill probly just stick with the weber, roller rockers,medium to large cam, not sure on the cam ill probly have a talk to waggots when im over that way next but what im asking is what pistons should i be looking at and whats the max compression ratio that is safe-ish? i dont plan go go past 6000rpm and reliability is more important than HP. any help?

[wagoon 2,429]

Acl race series are no longer made and you will be very lucky to find a set brand new at a retail store. If you ask nicely there are people here that have spare sets of pistons, good used sets are fine. Hypatec do make new pistons and have 3 different dished piston (29.3cc 20.5cc 5cc) and a flat top. Be aware that the hypatec have a larger compression height to acl which will require skimming the top off if the engine is at zero deck height already. Regarding engine compression it depends what fuel you are going to run as regular unleaded will need less compression than 95 or 98 and lpg can have a bit more depending on quality. Camshaft will also dictate compression as you have mentioned med to large cams, large requires more comp and diff gear change.

Hitting 6000rpm regularly is high for a reliable unbalanced crossflow, yes you can do it and many have but a balance is worth $200, alot cheaper than another rebuild.

[ando76 4,354]

^^^^^ what he said.  I doubt that you will have the cylinder head to be making power past 4500 - 5000 anyway so why rev it to 6000.  Your just making a whole heap of noise and stressing the engine for no real reason.

 

Stick a decent cam in it and use the strength of these engines - the TORQUE that they make.  The fastest two barrel speedway modified production car in Australia rarely sees 6000 rpm.  It has a mountain of TORQUE and that is why it wins races.

 

with a .40 bore, standard stroke, zero deck height and with standard pistons around the 22cc mark you will be around 10.7:1 comp.  Nice for a decent cam and still run 95 with the timing backed off a little.  Want to race it put 98 in and give it a few degrees.

 

The stock pistons will handle that comp all day with the tune right and you will have a torquey short rod motor that pulls like a 14 year old and will last forever. 

[ZL. 19]

Awesome thats the kind of info i was after ! , as far as i know the 86da motor should be a virgin block and should be totally original, as for fuel i always run premium, and i see what you mean about 6k being just noise, 5k will be fine i wont really give it a hard time it will probly be lucky to see 5k, as the fairlane will turn into a town car, now that i have a XG outback for towing and day to day shit, thats why i dont mind having a cam on the big side of things.

[ZL. 19]

Are these the ones wagoon? http://www.ebay.com.au/itm/ACL-Race-Series-Cast-Piston-Ring-Set-Ford-250ci-6cyl-x-flow-6mkry9411-Bowl-/251224701986?pt=AU_Car_Parts_Accessories&hash=item3a7e28bc22

 

or mabe just a new standard set.

[wagoon 2,429]

Less than a month ago I had to do the piston research. I rang that place and was told they did not have acl pistons in stock. I am still waiting on a reply to the 2 emails I sent at his request for specifics so make sure you ring and ask first before you commit to anything. I rang here http://www.precisionintl.com They are the importer for hypatec and had pistons on the shelf in the size I needed.

[ZL. 19]

Ah yeah sweet

 

cheers

[Duckboy01 6]

I've got a set of 250 ACL/MAHLE pistons and rings to suit the 200 rods that I am selling.