Question about custom pistons

[andrewb]

Now that I have the crankshaft and rods I need to start looking into having custom pistons made for a supercharged nitro engine.  For a manufacturer, I’m leaning towards Ross due to their familiarity with Ford Flathead engines. Anyone feel there is a better mfg for pistons out there?

IMO the most critical aspect of these pistons is making sure the piston dome matches that of the heads. Do I just need to send in a mold of the dome? I guess I could just call them but thought I’d ask.

I've done a great job at throwing money into this build so what “Optional Features” should I also consider? Gas ports, skirt/dome coatings, etc.

Oh, one more thing. The machinist always asks for a piston before boring, but if I make a piston mold it will be pre-bore.  What should be done in this case?


Thanks,

Andrew

[dreracecar]

I have a fondness for ARIAS pistons, Of coarse I have lunch with Big Nick everyday.

forged pistons are all pretty much all the same when dealing with Nitro, The cost and how soon they can be in your hands is the determining factor in most cases.
No on the gas porting, and the fuel coating(anodizing) doesnt hurt but adds to the cost
I would think that a Nitro piston for a FH would be a flat dome or even dished to get the comp down to a workable CR for nitro so a mold of the head chamber is not required.I would ask the piston maker
For me I would have the bores done and all equal then order 16 pistons and let the experts at the piston maker do there job at designing what will work for you. The days of hand fitting pistons to the bores are over due to the quality of machining nowadays. This is a NITRO motor and not a swiss watch, tollarences are generally on the loose side. The pins for the pistons for me would be the important feature to discuss, dont want a liteweight or too small pin causing problems when sorting out a nitro fuel system.

Talked to Nick--- they have a thick wall forging that will work perfect

[denverflatheader]

As usual (i.e. very commendable), dreracecar writes helpful timely information.  Same as Arias fh pistons, Ross makes excellent forged pistons for the fh.  For a third price comparison, I’d look at Diamond billet pistons.
 
http://www.diamondracing.net/pdf/Custom-Billet-Pistons.pdf

I had spoken to Ian at Ross a few years ago for a set of coated racing pistons.  If he’s still there, he will advise you should order the pistons from one of their distributors, back then it cost “much” less than ordering directly from Ross.  I ordered mine through Mike at H&H Flatheads.  Mike and their family business 1st Class.  I’d go with coating for supercharged nitro-methane protection, back then it added about $100 to the cost for set of 8.  I’ve seen coating kits on the internet for sale for do it yourselfers.  Here’s info on different type coatings:

http://www.jepistons.com/TechCorner/PistonCoatings.aspx

On piston design for fh pop-up heads, no help here.  Never seen one and no experience to share.  Might check to see if there’s compression ratio chart available for the Hanson heads with different bore/stroke combos already done.  Save you time mocking it up with scrap piston and grinding on to cc verify.  For me, I’d have to know the final compression ratio before I’d advance any further…

[jeff/21]

i sprayed the head and cylinder with pam installed the head turned the block up-side down then filled the head and about one to two inches in the cylinder with bondo let it cure then it just fell out leaving a perfect sample. how much nitro you will be running will determine the compression  as stated above flat piston will probably work the best.

[denverflatheader]

Jeff - neat solution, like it!.  Alan

[ricardo1967]

Here are a couple videos related to the topic:

How to pour a Chamber Mold Kit


How to scribe a line on the back of the chamber mold

[masracingtd1167]

Andrew before you jump into buying a set of pistons I would talk to someone who makes nitro pistons . I would highly recomend Bill Miller . It's not just the piston it self . It has a lot to do with where to put the ring grooves and how deep and what rings you use . My son wasted 2 sets of pistons on his nitrous big block before talking to Bill Miller .  As far as the bore size with a custom piston if you give them a finished bore size they will make the piston for that bore . Just my 2 cents !

[dreracecar]

Bill might not have the forgings for FH pistons and is not worth the effort for the amount he would sell over the years

[hemidakota]

I live in Carson City so bill miller and icon are both here in town. Have used both. If bill can make it his turn around is as fast as any and all of bills pistons are made to bore size. You can also call and talk to Icon(silvolite/united engine and machine)775-882-7790 and they also can make just about any custom piston there is. Both of them can scan heads to build what ever you need. I am far from an expert but have used both with good results. Have family that worked/works for both of them so that always helped me out in the past.

[masracingtd1167]

Bill might not have the forgings for FH pistons and is not worth the effort for the amount he would sell over the years

    You might be right about that Bruce but I still think it would be a good idea to talk to some one with nitro experience like Bill Miller or as you mentioned Nick Arias . I don't have a warm fuzzy feeling for Ross or there tech's . when my son wiped out the first set of pistons they did not offer much help in finding out the cause and told him his tune up was wrong .The same tune up we always ran !Another set of pistons  Have fuel pump and regulator flowed check everything possible put it all back together and 3 runs later wiped out 3 pistons again and ross's reply was your tune up was off ! It turned out to be a ring Issue that was spec'd wrong by Ross . My son called called Miller and Bill himself answered the phone . We sent him a piston and he saw it right away built us a new set of pistons and with no tune up changes the car is perfect . After about 30 runs so far cylender leakage is great . Sorry for the long post . Bill

[dreracecar]

The person anyone needs to talk to about nitro pistons is Roger McMartin over at Akerly&Childs (bearings and rings) in Valencia (CA.) absolutly theeeee most knowledable person on this subject with 40 years worth of expierence

[KeithDyer]

^^^^ X2!!

Bruce is dead right about talking to Roger.

Prolly forgot more about this stuff than we will ever know!!