I'm building a 406, the specs are as follows:

Scat steel 400 crank, internally balanced
Scat H-beam 6" rods
SRP Forged Flat-Top pistons

As far as rings go, the two I'm looking at are the Child's and Albert's Dura-Moly File Fit, or the Speed-Pro Moly File Fit [1/16 - 1/16 - 3/16]

Also, I should probably run the standard tension oil ring because I'll be doing a lot of my driving on the street, correct?

Thanks! :cheers:

 

JMHO offered here.

It depends a lot on your plans for the engine and how long you want it to run before you're ready to freshen it up again.

I would use the 5/64" ring pack if you haven't already aquired the pistons.
These might be a better choice for a street engine.
Either of the moly faced rings are a good idea. They will seat very quickly and seal nicely for a looonnngggg time.

You 'may not' need the file fit rings if the block is honed on the low side of the bore spec. But you can always set the end gap to whatever you want instead of whatever you get by using them.

If possible have EACH piston fitted to the cylinder you want to run it in by honing each bore for it's respective piston to get the skirt clearance you want.
You can't build a precision engine with generic machine shop work that a lot of folks get.

Again it depends on how you are going to use the engine AND what kind of pistons you will be installing.
Forged pistons will like a couple thousandths more skirt clearance.

Standard tension rings are also a good idea for a street engine.

 

Thanks for the good advice. :yesnod:

This motor will probably see less than 20,000 miles before its replaced. So longevity isn't really the issue. I plan on racing this summer at a local 1/4 strip and a few autrocross events. The pistons actually got here today, they are SRP Forged Flat top's for the 1/16 rings.

I am friends with my machinist, and he's going to let me use his shop to assemble the motor. :cool: We have been waiting for the pistons to get here, and we are going to fit them to the individual cylinders.

The skirt clearance suggested by SRP is .0020 - 0025". I can't belive how light these things are (424g). :crazy:
I was just curious as to any differences between the C&A and Speed-Pro rings, the speed-pros are about $20 more.

Here are the rest of the specs on the motor, how do you think it will run?

SBC 406 [deck plugs, lifter valley screens, torque plate bored and honed to 4.155", line honed mains, decked to .005" for total quench of .044".]
Scat Steel Crank lightweight (49lbs).
Scat H-beam 6" Rods 7/16 cap screws
SRP Flat Tops
Federal Mogul competition H-14 bearings
Comp Billet True Roller Timing Chain
Comp XR-288-HR Hydraulic Roller Cam (236/242@.050; .555I[1.6]/.540E[1.5]; 110LS; 106CL]
Airflow Research 195cc Street Head, angle plug, 74cc chambers
Edelbrock Victor Jr. Intake
Mighty Demon 750 Mech. Secondary Carb
MSD Pro-Billet Distributor
Crane Hi-6 ignition with LX-92 Coil.
10.5:1 CR
TH-400 with TCI Streetfighter Torque Converter (3300rpm stall)
Moroso Street/Strip Oil Pan, 7qt sump, scraper and windage tray
3.70 Rear Gear
10"W 26"D M/T ET Streets.

I would like to be somewhere in the mid to low 12's. Possible?

Thanks again
:cheers:


[Modified by VETDRMS, 3:32 PM 4/4/2003]

 

I just put in another set of speed pro's. There wasn't anything wrong with my last set after 20K miles. Leak down was less than 3% on all cylinders. I really didn't think that those small 1/16th ring would last that long. That's what came with my original JE pistons. I always used lite syn oil like 5W30.

I just did all new rings and bearings and a fresh block. Just take your time putting on the rings so you don't put any scratches on the pistons. Read the directions!!!!!!!!!!!!!!!!! Buy the solid aluminum ring compressor for your piston size. they are about $35. Swing the crank to a near mid cylinder position and use a wooden handle or large hard wood dowl with lots of sylicone spray to knock them in. Just use one hand to compress the rings in to fit it down in the solid aluminum ring crompressor. Practice makes perfect.:)

 

gkull Thanks, I will probably pick up the Speed-Pro's tommarow. :cheers:

This will be my second motor and I plan to be very meticulous! I have two of those ring compressors, one for 4.000-4.060" and 4.125-4.165". They are the aluminum type, but have a little room for adjustment (.040"). I used them on the 350 I built last summer and they worked SMOOTH. Certainly worth the $30.

Here is a question for you that I get mixed opinions on. I'm using a 2-bolt block, we are going to tighten the registers up, use ARP studs, align-hone it, and make sure everything is how it should be. I don't plan to spin this over 6500 rpm, but I'm woried the 2 bolt may not be strong enough, and I'd hate to blow my bottom end out. :eek: :U Its an extra $450 to install the splayed caps from miloden, which at the moment is a big stretch in the budget. The intake and carb alone are going to be almost $800.
*shrug*...gotta pay to play I guess. :smash:
Let me know what you think.

Thanks! :cheers:

 

The two bolt 400 blocks are supposed to be better than the factory 4 bolt 400's According to all the books your 2 bolt is good for mid 500 hp. You could go with stronger main caps and ARP studs.

Years ago i paid for splayed caps and something else broke and trashed the block anyway. I'm just running a fully studded 4 bolt now.

 

gkull Thanks, I was looking at the main caps from Pro-Gram / Pro-Line. I have the ARP studs already. What do you think of the support straps? I was looking at possibly using a front and rear support strap. Also, pro-line makes a stud girdle for SBC. If I am going to get new caps, I might as well get the splayed one as I would need the same machine work to fit the new steel 2 bolt ones. My machinist builds quite a few circle track motors, and he's confident I won't have any problems, I trust his opinion, but I just don't feel like losing an investment. :cheers:
Thanks again! :yesnod:

 

Internally balanced motors don't stress the block like heavy metal externals. I use a 6 1/4 SFI fluid damper and a light weight crank. Get the best balance job. I went with 685 gram H beam 6 inch bushed rods. which is a mistake in a way. the 580 or so Oliver's would be allot less swinging mass.

 

I used the Speed Pro's with the 5/64 top ring for my 406. I guess I will know more about them in a few thousand miles.

 

gkull Thanks, I'm using 6" H beam 6" bushed rods as well, but they weigh 645g. Big end is 460g, small end is 195g. Still a little heavy. I am going to inquire a little more about how they are going to balance it, what kind of balance job should I look for? Computer?

ld85 Thanks, I'm sure they will be fine. I will probably go with the speed-pro's. :cheers:

 

If you are referring to the print out sheet supplied in the box with the pistons, that is wrong!! That printed info was a mistake that went uncorrected. Either call SRP or take a look on their website for the correct clearance recommendations. 002"-.0025" won't cut it.

 

:eek: :eek: :eek:
I checked the website and they recommend .0025-.0035.

I will be sure to call them, THANK YOU! :cheers: