Slant Six Forum :: Twiggy - Long Rod Aluminum Block Engine Build-up

Frankly, as long as your tuning and compressioin choice doesn't make the engine dependent on the coating, it can't really hurt much and might help a good bit.

I spent some time getting the connection rods ready to go.

The rods get new ARP bolts and I grind smooth all the rough forging marks. I do not grind "flush" all the material along the forging seams, just smooth them out a bit. My thinking is to keep as much extra material along the beams as possible so a little bit of a raised forging seam along the parting line is added cross-section material.

I also grind and "round over" all the balance bob edges at each end of the rod, just to get some weight off the con rod.

Seeing that the pistons are set-up to use full floating pins, I drilled a .093 hole thru the small end of the rod, at a 30 degree angle and added a counter-sink. This will be the oil feed hole, to keep the pin-to-con rod surface well oiled.

After all the grinding and drilling, the rods were re-sized and balanced.
DD

Seeing that the pistons are set-up to use full floating pins, I drilled a .093 hole thru the small end of the rod, at a 30 degree angle and added a counter-sink. This will be the oil feed hole, to keep the pin-to-con rod surface well oiled.

The oil hole is an oil cup, it is pretty level when the rods are installed and holds some oil so it can flow into the pin area.
DD

Yes, a "steel on steel" interface for the pins, I did not want to weaken the rod's small end by boring them out and bushing them. I have run "steel on steel" before with good success, as long as there is lots of oil getting to the pin.

Author:	BigBlockBanjo [ Fri Aug 03, 2007 11:57 am ]
Post subject:	Re: More Piston Fussing...
Quote: Frankly, as long as your tuning and compressioin choice doesn't make the engine dependent on the coating, it can't really hurt much and might help a good bit. I would agree with that 100%.... I guess the worst case(as mentioned above) would be a piece flaking off, and creating a hot-spot. On an unimportant note, the pistons look cool now. Good Luck!

Author:	Doctor Dodge [ Fri Aug 03, 2007 5:47 pm ]
Post subject:
The trouble with coated pistons... no one will ever see them. (except everyone here ) I'm into it this deep... I will do the test. The good news is that my planned build-up is not dependent on needing the coatings. If the stuff goes out the exhaust pipe or into to the oil... Bye Bye, nice knowing you! My guess is that the moly based skirt coating will do some good and reduce the skirt scuffing that you see on many "run hard" piston skirts. I think the ceramic based piston top " thermal barrier coating" is "dust"... especially if I put any spray into the engine. DD

Author:	Kidd [ Sat Aug 04, 2007 8:39 am ]
Post subject:
I have to say, that this is a great info piece!! I love the step by step. Will you be bringing this engine in a car to Redding to make a run or 2? Andrew/Kidd

Author:	Doctor Dodge [ Sun Aug 05, 2007 9:06 pm ]
Post subject:
I am sure the engine / car will end-up at some of the SL6 races, that is how you find-out how well everything is working! (and if the build-up was worth all the work) DD

Author:	Doctor Dodge [ Sun Aug 05, 2007 9:24 pm ]
Post subject:	While my pistons were cooking...
I spent some time getting the connection rods ready to go. The rods get new ARP bolts and I grind smooth all the rough forging marks. I do not grind "flush" all the material along the forging seams, just smooth them out a bit. My thinking is to keep as much extra material along the beams as possible so a little bit of a raised forging seam along the parting line is added cross-section material. I also grind and "round over" all the balance bob edges at each end of the rod, just to get some weight off the con rod. Seeing that the pistons are set-up to use full floating pins, I drilled a .093 hole thru the small end of the rod, at a 30 degree angle and added a counter-sink. This will be the oil feed hole, to keep the pin-to-con rod surface well oiled. After all the grinding and drilling, the rods were re-sized and balanced. DD

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Twiggy - Long Rod Aluminum Block Engine Build-up https://www.slantsix.org/forum/viewtopic.php?t=23948	Page 7 of 25

Author:	slantzilla [ Sun Aug 05, 2007 10:26 pm ]
Post subject:	Re: While my pistons were cooking...
Quote: I spent some time getting the connection rods ready to go. The rods get new ARP bolts and I grind smooth all the rough forging marks. I do not grind "flush" all the material along the forging seams, just smooth them out a bit. My thinking is to keep as much extra material along the beams as possible so a little bit of a raised forging seam along the parting line is added cross-section material. I also grind and "round over" all the balance bob edges at each end of the rod, just to get some weight off the con rod. Seeing that the pistons are set-up to use full floating pins, I drilled a .093 hole thru the small end of the rod, at a 30 degree angle and added a counter-sink. This will be the oil feed hole, to keep the pin-to-con rod surface well oiled. After all the grinding and drilling, the rods were re-sized and balanced. DD Doug, will those be floated steel on steel?

Author:	SlantSixDan [ Mon Aug 06, 2007 8:16 am ]
Post subject:	Re: While my pistons were cooking...
Quote: Seeing that the pistons are set-up to use full floating pins, I drilled a .093 hole thru the small end of the rod, at a 30 degree angle and added a counter-sink. This will be the oil feed hole, to keep the pin-to-con rod surface well oiled. I'm not sure I understand. What's the oil path to/from this hole?

Author:	LUCKY13 [ Mon Aug 06, 2007 10:26 am ]
Post subject:
If I understand right, its like a little well to trap and hold oil to feed oil between the pin & rod. With it coming in at the 30 degree like he did it could hold oil like one of those little oil caps where you feed oil to a bushing in a Dizzy (some of the older ones). You know one of those with the little flip top caps where you take your oil can and give it a squirt. Only his will be catching oil that is slung up from the crank, and even coming form the oil ring return holes, and feed it down to the pin. Should work very good. Jess

Author:	Doc [ Mon Aug 06, 2007 1:20 pm ]
Post subject:
Yes, a "steel on steel" interface for the pins, I did not want to weaken the rod's small end by boring them out and bushing them. I have run "steel on steel" before with good success, as long as there is lots of oil getting to the pin. The oil hole is an oil cup, really more like a funnel, it is pretty level when the rods are installed and holds some oil so it can flow into the pin area. DD

Author:	AnotherSix [ Mon Aug 06, 2007 2:03 pm ]
Post subject:
I suppose if the steel on steel did become an issue you could have a set of pins made with a hard chrome exterior. $$$ When will the head debut?

Author:	emsvitil [ Mon Aug 06, 2007 2:19 pm ]
Post subject:
Quote: The oil hole is an oil cup, it is pretty level when the rods are installed and holds some oil so it can flow into the pin area. DD With the violent motion of the rod, I'd think any oil would just be flung off............

Author:	Doc [ Mon Aug 06, 2007 5:04 pm ]
Post subject:
The small end of the rod is pretty stable as far as "swing" goes but the super-sonic up - down motion will simply not allow for a topped-off cup full of oil. The main idea is to catch some of the oil spray and drive some down into the drilled hole and onto the center of the piston pin's running surface. All that aside... the holes took some weight off the rods. (just kidding) DD

Author:	440_Magnum [ Tue Aug 07, 2007 12:59 pm ]
Post subject:
Quote: Yes, a "steel on steel" interface for the pins, I did not want to weaken the rod's small end by boring them out and bushing them. I have run "steel on steel" before with good success, as long as there is lots of oil getting to the pin. Now your're scarin' me, Doc. My Mopar-specialist engine builder 'bout had a coronary when I took him a 440 that had been built with the pins floating directly in the rods (I didn't know it, I bought it for other parts but thought the rotating assembly could be used as-was). OF course this was going to be a long-life street engine, not a racer.

Author:	slantzilla [ Tue Aug 07, 2007 1:21 pm ]
Post subject:
I have run steel on steel in a street/strip Slant. It was driven 50,000 miles all over hell and back with 3.91 gears in it, and made 1500 or so passes at the track too. The rod end were a little loose when we tore it down, but it had succumbed to the dreaded oil pump gear failure, so that may also have had an effect on it. Lots of dirt track guys run them sos, and I don't think anything is harder on rods than a dirt motor.

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Author:	DionR [ Tue Aug 07, 2007 2:18 pm ]
Post subject:
I see no reason for floating pins, unless you plan to spin this thing pretty high. And I think the hole in the small end of the rod is just one more place for it to fail.