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Author Topic:   406 building tips
rpm20
Dirt Freak

Total posts: 347
posted November 23, 2005 10:41 AM  
putting together a 406 .040 over, 509 casting block,cast crank, speedpro pistons ,powdered metal rods 5.7 length.
what other things should i do to make it reliable and build power for an imca mod.
any clearancing info or other tips appreciated.

PEwaste
Dirt Full Roller

Total posts: 38
posted November 23, 2005 11:02 AM  
Have the rotating assembly balanced...

For clearances with Speed Pro's, I've always been taught and used .0045 on the cylinder to piston, .00225 on the rods and .0025 on the mains with .018-.025 side clearance on the rods.

Use a good assembly lube, make sure you are dirt/dust free where your building it and you should have no problems. A good quality machinist will be able to set all your clearances.

I like to use Clevite bearing lube for bearing lube. It's pretty good for break in or if your engine is going to sit a little while. Main thing is try not to twist it too hard, 6700 would be about max for a 406 with Speed Pro's.

Cam it right and take care of it, you'll be happy with it.

"Xtreme12x"

mtmod50
Dirt Roller

Total posts: 15
posted November 24, 2005 07:38 PM  
don't use a 4 bolt STOCK block use a 2-bolt,a 2-bolt splayed is even better!4-bolt stock 400 is very weak!!!!!!!!!!!!

A. Bighurry
Dirt Full Roller

Total posts: 40
posted November 25, 2005 07:15 PM  
A 509 casting should be a 2 bolt. At least, the ones we've used have been.

johder
Dirt Maniac

Total posts: 113
posted November 26, 2005 09:42 AM  
yes a 509 was a 2 bolt...you can splay them. you will just have 2 angled bolts.

Sidebite252
Dirt Maniac

Total posts: 105
posted November 26, 2005 04:22 PM  
The only thing I would add (or confrim) is the .0025 clearance on the crank & rods. I've tried to run .0015 and it was too tight and we scorched & spun the bearing on the journals that were that close. good luck.

I also agree with 2 bolt. We never twist our 406 more that 6500 to 6600 and its working out great. nice low end pull. I wouldn't worry about a splay unless I was planning on twisting the motor over 7K.

[This message has been edited by Sidebite252 (edited November 26, 2005).]

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