Another Rebuild

Landyacht · Dec 6, 2015

With aftermarket aluminum heads you also have the option of open or closed chamber and a variety of combustion chamber volumes and aluminum doesn't retain as much heat as cast iron so you don't have as much detonation issues with pump gas.

70bigblockdodge · Dec 6, 2015

Oh crap lit a fire that will quickly go out of control!;)

So for $1600 you get OOTB eddy heads on my doorstep that will out flow H.O.G. ported heads for 1450. Now Fred is not even thinking about needing flow numbers like that sure they would be nice but if you cam only goes to .450 and you aren't putting headers and free flowing exhaust and spinning to 6-6500 what are you really gaining.

Landyacht · Dec 6, 2015

70bigblockdodge said:
Oh crap lit a fire that will quickly go out of control!;)

So for $1600 you get OOTB eddy heads on my doorstep that will out flow H.O.G. ported heads for 1450. Now Fred is not even thinking about needing flow numbers like that sure they would be nice but if you cam only goes to .450 and you aren't putting headers and free flowing exhaust and spinning to 6-6500 what are you really gaining.

I admit that some of us performance oriented guys can get a little out of hand. Its in our nature.

commando1 · Dec 6, 2015

Fred, being the wise and logical man that he is, is staying with his iron and the issue now a moot point.

detmatt · Dec 6, 2015

This is where I go.

Fratzog · Dec 6, 2015

Appreciate the varied opinions here. Sticking with the existing heads is my preference and I will share your thoughts with my shop during my weekly visit. I will be most interested in his thoughts on the merits of valves & "cleanup" given my limited budget and previously stated objective.

moper · Dec 8, 2015

A modern valve job that uses cutters (5 angle) will do 90% of the bowl cleanup work. The actual blending by hand takes all of about 4 minutes for both heads after that. I pay $450 for a valve job and get that bonus as part of the normal work. Replacing the stock valves with nailhead stainless performance valves will gain another 10-15cfm for the difference in cost between stock and performance valves (under $100) & as part of the rebuilding process. So shop around if you have the ability to.

440_Magnum · Dec 8, 2015

Fratzog said:
I didn't know it either but they apparently fit although there is an issue with the angle of the rod. /

On *factory* pistons, the wrist pin is offset slightly toward one side of the piston instead of being perfectly centered. What that does is make the piston want to stay "tilted" (we're talking thousandths of an inch) in the bore and always the direction it wants to tilt on the power stroke due to the piston 'pushing' on the side of the cylinder, and that makes it quiet at the expense of making more friction. The "old rodder's trick" is to flip the piston around so that on the power stroke, the built-in "tilt" is working against the angular forces and the piston floats more neutrally in the cylinder reducing friction. The price you pay is that now the piston *always* rocks from one tilt to the other at TDC and creates piston slap.

FWIW- almost all aftermarket pistons are built with centered pins so the old-school trick doesn't do any good anyway. In this case, your engine builder thought he was building a Ford (or BB Chevy, or Hemi) with all the intake valves on the same side of the bore... so he only installed half of them backwards. Not deliberate, a careless mistake!

Another FWIW: those KB pistons look very similar to the ones I'm running in my Polara (mine are 90's vintage, un-coated skirt hypereutectics) and yes they are LOUD. Mine sounds like an old 7.2L Powerstroke when its really cold. Newer KBs and other brands use coated skirts and are way, way quieter. Another change for my next build....

moper · Dec 9, 2015

"mine are 90's vintage, un-coated skirt hypereutectics"

If they are set to the KB recommended bore clearance, which is a little less than about 1/2 of what typical forgings of the day wanted, they would be silent. None of mine have been loud even after 30-40K miles on them. It's the right clearance, not the coating, that makes them quiet. All hypers are not made the same either. KB wants .0015-.0025 piston to wall depending on the bore size. Forged are .0035-.0045 depending. When they first came out, those machinists that did not read the instructions fully would set them and the ring end gaps wrong.

commando1 · Dec 9, 2015

moper said:
"mine are 90's vintage, un-coated skirt hypereutectics"

If they are set to the KB recommended bore clearance, which is a little less than about 1/2 of what typical forgings of the day wanted, they would be silent. None of mine have been loud even after 30-40K miles on them. It's the right clearance, not the coating, that makes them quiet. All hypers are not made the same either. KB wants .0015-.0025 piston to wall depending on the bore size. Forged are .0035-.0045 depending. When they first came out, those machinists that did not read the instructions fully would set them and the ring end gaps wrong.

How does guy in his garage achieve that piston to wall clearance?
You have the machine shop go, let's say, .030 over on the bore.
You buy .030 over pistons.
Then what.

Wollfen · Dec 9, 2015

commando1 said:
How does guy in his garage achieve that piston to wall clearance?
You have the machine shop go, let's say, .030 over on the bore.
You buy .030 over pistons.
Then what.

Whenever i have had a block bored I had to supply the pistons before they started the job so they could match each piston and mark it so that each piston was a custom fit to each bore.

440_Magnum · Dec 9, 2015

Wollfen said:
Whenever i have had a block bored I had to supply the pistons before they started the job so they could match each piston and mark it so that each piston was a custom fit to each bore.

This. A good machine shop will inspect the block and determine what the minimum overbore is. Then you buy the pistons. Then the shop mic's the pistons and sets the bore to be the correct clearance for the actual pistons used, very tight for HE pistons, looser for stock, loosest for forged.

That being said, un-coated hypereutectic pistons can *still* be very loud, especially if they're a low-friction piston with a short skirt and a centered pin location. GM had the same problems with piston slap in their production LSx engines with similar pistons. The machinist I used for mine did exactly what I described above, and the 1990s vintage KB hypereutectic pistons still sound like a 7.2 Powerstroke when its cold. Coating the skirts seems to be the only fix to make that kind of piston as quiet as factory.

commando1 · Dec 9, 2015

I obviously dont have a good machine shop, then.

300rag · Dec 9, 2015

commando1 said:
I obviously dont have a good machine shop, then.

Is this the inspection department?

and the machinist?

65Fury440 · Dec 9, 2015

I totally missed this thread. Good info, I never thought about the exhaust valves being paired (No heads yet to look). I had an oh sh*t moment while running to the garage. Good luck with your rebuild OP, sounds like the updated engine will be much better.

Fratzog · Dec 11, 2015

Looks like the pistons are on back order so it may take a bit longer to get everything together. Here are a few more pics from my visit today.

Fratzog · Dec 19, 2015

Another few pics from today. Block is bored another .010 (total .040 over) and confirmed adequate. The forged pistons ordered and moley rings have been ordered but due to back order likely won't be in until New Year. Shop still figures we will be on target for factory 440 HP specs. I was hoping to drive the car home but it likely won't happen on mid-January roads around here.