[94cobra69ss396]

I have some time before I need to get a crank as we've had to put this on hold.

As far as I know the rods are stock. They are out of an engine that my dad had in his boat as is everything else except this block. I haven't looked for rod bolts yet but will most likely be ARP.

I'm going to run the Comp cam that was in it as well which is a hydraulic flat tappet. It's the Magnum series and has 253 @ .050 with a. 525 lift. He originally bought it with the K kit which comes with the lifters, springs, timing set, etc. He had the Sportsman heads set up with those parts back when he first put the old engine together. It was powering his jet drive boat but never saw over 5000 rpms because of the low compression and mismatched impeller.

Here's the measurements for the small and big end.

[BRUTAL64]

Originally Posted by 94cobra69ss396

I have some time before I need to get a crank as we've had to put this on hold.

As far as I know the rods are stock. I haven't looked for rod bolts yet but will most likely be ARP. They are out of an engine that my dad had in his boat as is everything else except this block. I'm going to run the Comp cam that was in it as well which is a hydraulic flat tappet. It's the Magnum series and gas 253 @ .050 with a. 525 lift. he originally bought it with the K kit which comes with the lifters, springs, timing set, etc. He had the Sportsman heads set up with those parts back when he first put the old engine together. It was powering his jet drive boat but never saw over 5000 rpms because of the low compression and mismatched impeller.

Ok, then. Heat treat the rods (after polishing the rod's I beam) BEFORE you resize the big end and add the new rod bolts. You probably already knew this, but I'd thought I remind you.

[94cobra69ss396]

How do you heat treat the rods? I'm going to have the old pistons pressed off so I can polish the beams. Once I'm done I'll heat treat them your way. After we're back on I'll get the new pistons and a crank then have the rods reconditioned, the new bolts installed, pistons pressed on and then have everything balanced.

[BRUTAL64]

Originally Posted by 94cobra69ss396

How do you heat treat the rods? I'm going to have the old pistons pressed off so I can polish the beams. Once I'm done I'll heat treat them your way. After we're back on I'll get the new pistons and a crank then have the rods reconditioned, the new bolts installed, pistons pressed on and then have everything balanced.

Your wife is going to love this; Pre heat your oven to 450 degrees and cook the rods for 8 hours. That's it.

First heard of this in 1969--it started with having to heat treat the rear end gears in a Chevy 12 bolt. Doing the heat treating allowed the gears to last a whole season instead of 4 or 5 runs.
Same idea with rods---it works.

BTW; Some guys think 16 hours is better-- not sure I agree.


BTW2: do you want me to look over the heads and see what porting you can do? The "old" Sportmans had a very bad exhaust port.

[BRUTAL64]

Originally Posted by 94cobra69ss396

I have some time before I need to get a crank as we've had to put this on hold.

As far as I know the rods are stock. They are out of an engine that my dad had in his boat as is everything else except this block. I haven't looked for rod bolts yet but will most likely be ARP.

I'm going to run the Comp cam that was in it as well which is a hydraulic flat tappet. It's the Magnum series and has 253 @ .050 with a. 525 lift. He originally bought it with the K kit which comes with the lifters, springs, timing set, etc. He had the Sportsman heads set up with those parts back when he first put the old engine together. It was powering his jet drive boat but never saw over 5000 rpms because of the low compression and mismatched impeller.

Here's the measurements for the small and big end.

After heat treat and adding the new rod bolts you will need the resize the big end. Are you going to bush the small end for floating pins---I suggest this.

[BRUTAL64]

One more thing---The rods you have are the same that I used in my 400 I build as a test engine in 88. I FINALLY broke 4 pistons five years ago.


I took that engine to over 7,000 rpm all the time--but, that is not the same as doing 100 laps with heavy load on and off load. That's what breaks stock rods loading on and off contuinlessly.

Just letting you know I have used the same rods. I went to Scat rods so I wouldn't have to worry about breakage.


I hope the info I am giving you is helping.

[94cobra69ss396]

Originally Posted by BRUTAL64

BTW2: do you want me to look over the heads and see what porting you can do? The "old" Sportmans had a very bad exhaust port.

Sure. I looked at them and they can definately be improved but I'd love to get your opinion. My dad bought these back around '97-'98 I think and why he went with the 72cc combustion chambers is beyond me.

Originally Posted by BRUTAL64

After heat treat and adding the new rod bolts you will need the resize the big end. Are you going to bush the small end for floating pins---I suggest this.

Bushing the small end depends on cost and what I can afford to do when I'm ready. I'll have the machine shop install the new the new rod bolt and resize the big ends as well as do the balancing when I'm ready to start assembling it.

Another question, should I do the heat treating with the old bearings still in the rods or remove them? I didn't know if having them in would help with anything.

[BRUTAL64]

Originally Posted by 94cobra69ss396

Sure. I looked at them and they can definately be improved but I'd love to get your opinion. My dad bought these back around '97-'98 I think and why he went with the 72cc combustion chambers is beyond me.




Bushing the small end depends on cost and what I can afford to do when I'm ready. I'll have the machine shop install the new the new rod bolt and resize the big ends as well as do the balancing when I'm ready to start assembling it.

Another question, should I do the heat treating with the old bearings still in the rods or remove them? I didn't know if having them in would help with anything.

I actually found a set of stock rods bushed and resized ready to go for $119.
Floating pins are much easier to assemble. Plus, there is no impact on the pistons if you don't get the pressed pins in just right. If you don't get the pin correct (while the rod is hot and the pin is still cold) the very first seconds- then they'll need to be pressed on with a (I used a 12 ton) press and that can be hard on a piston if not done correctly.
Now one more thing on the rods---Once you get all the pricing together to redo your "X" rods how much more would it be to get a set of Scat rods???

They do have a set of Pro Stock 3/8 cap screw rods (8) for 233.00- maybe less. I got a set of these for the 400 I'm building.

Make sure the rods are super clean and no bearings in them. Clean is important, cause of the smell while you cook them.

The 72cc chambers are pretty good-cause they can unshroud the valves better than a 64cc. I'll need to see them.

So when do I do a head porting class???


Can get you a set of Alum heads to your door for 685.00.

Aren't I great at spending OTHER people's money.

[enkeivette]

Lurk

[BRUTAL64]

Originally Posted by enkeivette

Lurk