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Technical => Matt Shaff's Engine Shop => Topic started by: Supercat on May 07, 2020, 06:39:44 PM

Title: Piston questions
Post by: Supercat on May 07, 2020, 06:39:44 PM
I need to order pistons soon for my next engine.
The specs  solid cast aluminum Buick block no water jackets.
Heads flow 490 cfm. at our cam specs and rocker ratio.
Crank is a 3.750 stroke 7.0" rods
Bore is 4.500
Gasket range .040 to .100
6:71 to start and may move up to an 8:71 later.
Enderle injector and port nozzles on alky.
We are shooting for about 11.5 to 1 compression with the .040 gasket.
This is going in our Supercat FED.
Questions are;
1 how far down for the piston?
2 how far down should the top ring be?
3 what style top dished,  flat, ?
4 should the pistons be coated?

Let me know your thoughts folks.
Thanks
John
Title: Re: Piston questions
Post by: dreracecar on May 09, 2020, 09:01:26 AM
What class is your plan???

 Engines do not know whos name is on the valve covers
 big swing between .040 and .100 for head gaskets that manifold sealing can be an issue,  stick with one size and build with that (I prefer .063 copper)
 you still have to put fuel in the hat anyway and I dont see any real gain by running port nozzles, It just complicates things (at the level we run)
 My preferance is around  10.2 to .5 , but thats just me.
 
 Your questions should be directed towards who will be making your pistons and will need to supply them with  the block deck hight  and  cylinder head volume  along with valve dia and cam lift in order to create a piston that will work for you--- without that info-- good luck

 as towards coatings, I do see that it helps when running nitro. but they still burn them up,  but no bennifit when alc is the fuel,  If you do have problems, its not the pistons fault and coatings will not help

  Berri Meza @  TRAUM Racing Pistons    310 259 5299   Head piston designer for ARIAS pistons before they closed shop and sold to CP  You will talk to him direct
Title: Re: Piston questions
Post by: 225digger on May 09, 2020, 12:11:54 PM
x2  on traum pistons.   i cannot answer any of your questions, but had them make me a set of 392 pistons last yr for a cackle engine.  all said i think it was around 1200.00  8 custom pistons, nitro coating, pins, buttons, rings....... i have never talked to him on the phone all done via email, he was happy to chat but i was good with emails.   give them a look.
Title: Re: Piston questions
Post by: wideopen231 on May 10, 2020, 08:15:08 AM
I always order a ten set when getting pistons. Lot easier to replace one if you have two handy. Never know when a valve might break out you just burn one.
Title: Re: Piston questions
Post by: crider on May 10, 2020, 03:58:59 PM
Chris is right on the money, order 10. If you burn or break one, you'll lose a lot of time waiting for a replacement, and most piston companies will sock it to you on price if they have to make you one custom slug