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Tom,

What method do prefer when polishing the CR's? Do you use a die grinder with a sanding disc, or a 4.5" grinder with a flap disc? I'm planning on doing this when I start to put my 392 back together.
 

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Tom,

What method do prefer when polishing the CR's? Do you use a die grinder with a sanding disc, or a 4.5" grinder with a flap disc? I'm planning on doing this when I start to put my 392 back together.
The official answer is never ever go "across" the rod, but always ALONG the rod. You can't do that with a circular grinder.

That takes forever, BTW.

My compromise solution is the 4.5" grinder with the flap wheel to knock down the high stuff first, then I start in on the die grinder with cartridge rolls, dropping down in grit until I get to the flap wheels for the die grinder and then the cross buffs.

You want the scratches to run along the beam, not across it. One of the advantages of polishing is to remove any stress risers, resulting in a stronger rod. If you go across the grain, that's counter productive.

You also lose some weight, obviously.

And you remove the little porous spots in the metal that used to hold oil (increasing the weight and removing that oil from circulation) - it now sheds the oil instead of oil clinging to it. Reduces reciprocating mass.
 

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Discussion Starter #223
Tom I am working on the 304/392 this weekend, I'm thinking my standup belt sander will make short work on the rods. Also got the header and intake flanges from Richy, I will post up some pictures this afternoon. Plan is to get this moving, but the HCS is coming back to my shop this weekend and I have two baggage carts and a Lav cart in the Shop now.
 

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The official answer is never ever go "across" the rod, but always ALONG the rod. You can't do that with a circular grinder.

That takes forever, BTW.

My compromise solution is the 4.5" grinder with the flat wheel to knock down the high stuff first, then I start in on the die grinder with cartridge rolls, dropping down in grit until I get to the flap wheels for the die grinder and then the cross buffs.

You want the scratches to run along the beam, not across it. One of the advantages of polishing is to remove any stress risers, resulting in a stronger rod. If you go across the grain, that's counter productive.

You also lose some weight, obviously.

And you remove the little porous spots in the metal that used to hold oil (increasing the weight and removing that oil from circulation) - it now sheds the oil instead of oil clinging to it. Reduces reciprocating mass.
OK! I see it now. I can understand why it will take a long time.
 

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Tom I am working on the 304/392 this weekend, I'm thinking my standup belt sander will make short work on the rods. Also got the header and intake flanges from Richy, I will post up some pictures this afternoon. Plan is to get this moving, but the HCS is coming back to my shop this weekend and I have two baggage carts and a Lav cart in the Shop now.
A belt sander would be a good way to get a head start.

Do keep in mind that you already paid to have that bottom end balanced, and if you polish the rods you will need to haul the crank, rods, pistons, balancer, and flexplate back to a machine shop to have it rebalanced.
 

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Discussion Starter #226
Yep, thats the plan. The flex plate they used has a bad section on it and my luck it will trash out the first time I twist the key. I am only looking to polish the rods and get them lightened up a little. I talked with Tim today and scored a set of 345 heads with 392 exhaust valves, they are already ported and polished so I think they are the cats meow for my motor. Bill Springer was by my shop today and is ready to Tig the manifold and exhaust system. I am hoping to get the bed and cab removed from the frame soon so I can get all the welding done, frame smoothed out and in for powder coat soon.
 

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Discussion Starter #227
First look at the flanges that Richy did for me. These should be nice when we get them all TIG welded Soooooon I am hoping, got to move forward with HCS then the Hotrod will be up :smokin:
 

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Discussion Starter #229
I spoke with Richy and he is doing a bit of pre order research on flanges. If anyone wants a set of exhaust or intake flanges, shoot a PM to pro-rallye here on the board. He's got a D series truck so he's not all bad. And he is the fellow that made the ones for me.........Robert
 

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I found out some new info on the camshaft situation. An old pulling friend of mine told me they used to turn down the rear journal on the steel cams to press on a cast iron distributor gear. To make up for the smaller journal they would use a roller bearing instead of a lead bearing. Perhaps the same method could be applied to the sv cam, just on the front.
 

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Now, on to the hours and hours of grinding and the abuse I dished out to my air compressors.

I have a pattern now - the switches are staggered, so I run the crap out of one of them at "high pressure" and then shut it off, let the second compressor kick in after a bit more depletion of the air reserve and let it chug away for a while, before switching the first back on - and maybe the third on - and letting them all catch their breath for a bit.

Anyhow, for porting (and rod polishing) you'll want the following. On the heads, you want to start with a carbide burr, too.



Those are primarily cartridge rolls, with a stone or two, and then flap-wheels and cross-buffs.

After 120 grit roll (which was after the 80grit)

Then the flapper



(You can see I should've gone a little deeper with the 80grit)

The first cross-buff


And after the finer cross-buff.



And boxed up for a trip to the machinist.



I had to go rummage about in my shed for a while to find a good dual-pattern flexplate. I'm taking two "large pattern" flexplates in with it to have re-drilled. Seems JetFxr got my last spare.

Loaded a pile of stuff to take to the machine shop - it all needs balanced now. Then I can do a mock assembly and measure the deck height and haul the block back in for more decking.
 

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I bought some oval port BBC header gaskets while visiting the machine shop today.

These are the flanges JetFxr sent over.


The Chevy gaskets on the Chevy header



JetFxr's flanges on the Maulis head - they don't exactly line up with the exhaust ports. I think these were the Ebay flanges.


And the Chevy gasket on the SV

Tight fit..


Not much overlap.


 

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$300 at the machine shop today..

Pistons weigh 936g
Rings 69g

Rod (small end) 229g, Big end 613g (842g total per rod)
Total rod + piston +ring of 1234g.

Reciprocating weight of 2,468g. Rotating weigh of 1393g.

Used a bob weight of 2627.0g (except for one off-weight rod that got a 2637.0g bob).

All balanced and ready for the trial assembly, at which point I check the deck height and then tear it back down and have the block machined down to raise the compression.
 

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Deck height has been checked.




#1 is .044 in the hole, #2 is .042
#7 is .035, #8 is .034.

so almost .010 out of square.

Block is bare again - bearings cleaned and back in the box, pistons and rods back in their place and covered, crank bagged again.

I might polish the drain backs this week, then it's back to the machine shop for decking.

Yesterday, I was all but set on having .055/.065 removed, putting the pistons .020 out of the deck at TDC.

Then I re-read here that Jim indicated .060 was already cut from the heads and have to think on it a little again.

I believe .100 is considered pretty safe. I would be at a net of .120, while keeping in mind the extra stroke added.

3.656 stroke vs 3.690


That's 0.34 extra stroke, or 0.17 higher at TDC for a NET change of .137" between the position of the piston at TDC compared to the valves, less the offset wrist-pin on the aftermarket pistons (since most replacement IH pistons have the wrist pin closer to the crown to LOWER compression)
 

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What sort of machine is used to deck the block?
If it is BHJ and is piloted off the crank CL wouldn't that square up the deck?
Or at least square it to the crank CL.
 

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What sort of machine is used to deck the block?
If it is BHJ and is piloted off the crank CL wouldn't that square up the deck?
Or at least square it to the crank CL.
I don't recall the specifics of the machine, but they square it to the crank CL when it's decked. They have every other time I've had my blocks decked.

In the past it was just "take this much off" and it comes out that much off at one spot and a little more or less at the other spots.

With .010 difference front to back, it's my intention to tell them my goal for the front and goal for the back, and to square it to get as close to those numbers are they can.

(I'd hate to spec it for one side, and they use that number on the opposite instead, and it winds up .010 higher or lower than I wanted. For most of my junk, that's tolerable, but not for this motor. .030 out of the deck is too close to losing a ring and only leaves .008 to .012 before the head gets a headache.. and .010 out of the deck is going to rob me of some compression and corresponding power, though that would still be OK)
 

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Tom I see a lot of work you have put into getting the bottom end ready.
The lighting of the rods, polishing all over the place. But what are you going to do to the heads? I think I've seen where you open the exhaust to match the gaskets and some stiffer springs. But anything special in the valve job? I remember the old days when somebody would over port their heads and the motor would have no bottom end.

When my was done, they just took a carbide grinder to the intake and exhaust to smooth out the ports. Not polished. The exhaust was not opened up much, just the air hump removed.
 

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Tom I see a lot of work you have put into getting the bottom end ready.
The lighting of the rods, polishing all over the place. But what are you going to do to the heads? I think I've seen where you open the exhaust to match the gaskets and some stiffer springs. But anything special in the valve job? I remember the old days when somebody would over port their heads and the motor would have no bottom end.

When my was done, they just took a carbide grinder to the intake and exhaust to smooth out the ports. Not polished. The exhaust was not opened up much, just the air hump removed.
For this motor, you see all of the bottom end work because *I* am doing nothing to the heads.

Heads were provided by Jim Maulis Jr.

These are late 345 heads. They were sent to MPG Headservice in Colorado. MPG has a CNC program setup for porting IH heads, and these heads were done on that machine.

Is it the BEST head porting job ever done? No. I have the flow numbers from these heads, and the flow numbers from some heads Jeff Ismail did, Dave Sr's heads, and from another guy, and these heads fall short of those numbers, but not by a great margin.

On the upside, you can ship a set of heads to MPG and pay them the ($2k IIRC when I called) money to have it done, and be pretty assured of the results. Repeatable results, too.

Robert, It's Jim Maulis. ...I would chime in on the late style 345 heads you picked up from me. As I remember they were milled .060, L88 chevy intake valves, FE427 exhaust valves. The valve springs were matched for a .500" plus cam that Scott at MPG heads ground for the heads. Scott did all the port and valve work . I have a factory IH race head that came off one of the Baja Scouts. The above heads flowed better than the IH race head, but can't remember the numbers.

I have 4 sets of ported heads here.

I did my first set of 345 heads for my trail rig. I knocked down the exhaust hump, gasket matched, and polished. Nothing too wild. I did not have access to a flow bench at the time. The intake was barely touched.

I have the 304 heads done for the old race mill by Gryphin. I had them flowed the last time I overhauled that engine, so I have some good numbers from those heads. They were done more extensively than my 345 heads.

The third set of ported heads are the IC392 heads I did for my Travelette. This time, I had a better idea of what I was doing, and what I wanted to accomplish.

I gasket matched the intake and knocked down the casting flash, but left the finish rough.

On the exhaust, I gasket matched - to the header gaskets, not manifold gaskets (they are different!) the ports, removed the A.I.R. humps, and then on OldScout's advice went farther in and removed the bottom of the valve guide, blending all of that together.

I also widened the port a bit, and tried to reduce the radius of the turn.

It was all then polished.

The chambers were then polished, and I relieved the head chamber and block ever so slightly where the valves were shrouded by the cylinder wall/chamber wall.

I also used back-cut exhaust valves to lighten the valve and improve air flow by an estimated 5cfm (according to DaveSr, who sold me the valves).

I did not have access to the flow bench when I did those heads, so I have no good numbers for them.

All three heads run BBC valve springs. LS6 on the 345, hi-po LS6 on the 304, and regular HO454 springs on the 392 (the tow motor wasn't intended for 6,000rpm operation like the others).

The machine shop replaced the LS6 springs on the 304 with some comp-cams springs they recommended, and now instead of floating the valves at 6300rpm, it's more like 5200rpm. :mad3:

My last visit, the machine shop talked about running two different valve springs. One "light" set for break-in, then replacing the springs with something heavier, in the 400+lbs range when open. My new LS6 springs on the 345 measured 355lbs open, which caused a panic by the machinist afraid of wiped cam lobes in short order, until I pointed out the 1" diameter lifters and the heavy valves.

Now, of course, we have the lack of ZDDP to deal with, which comes back to running a light spring for break-in, then a heavier one later.

Which brings me to the 345 heads that Maulis did. I had them flowed (numbers are earlier in this thread)

Ahh.. Here are the flow figures.

These are the best photos of the ported 392 heads. I lost the polished rods and work-in-progress head porting in a hard drive crash.





If you look closely, you'll see that the outer two ports are "shifted" inboard a bit, because Stan's header pattern is OFF and port matching to the header ends up moving the exhaust port over 1/8" or 1/4".

I'm running the special 74/75 truck headers on that motor, in my 1974 Travelette.

Since you mentioned carbide, I'll add that "today" I go after the head with a carbide burr in my die grinder and knock down the worst of it and do most of my shaping.

I then move to the stone (maybe), then the 80-grit cartridge rolls (like I used on the rods) and then work my way up to the cross-buffs when I'm done (on the exhaust).

Turn down the air pressure so you can run the die grinder "full on" but at reduced RPM for longer abrasive life and more control. Even more critical if you have an aluminum head.

My first 345 head took a month of evenings and weekends (and greatly abused my 1hp 220 compressor). The second head took two weeks, knowing how much to use the stone first.

My 392 heads took 1-2 weeks each IIRC, and that's when I moved up to a 5hp compressor and the carbide burr instead of the stone for the first cut.

Now I'm using two 5hp compressors in tandem (one 5hp draws 20amps, one 30amp) to keep the die grinder happy but they both run pretty much non-stop when die-grinding or bead blasting.
 
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