I have a set of H beam rods that have been exposed to heat due to bearing issues. The bearings didn't spin but they were ruined because of tight clearance. So I am trying to find out if the rods can be rebuilt? Also, could they be trusted in a very healthy 500" stroker?

Thanks,
Digger73 (Mike)

If the rod discolored, I would replace it. If it is a cracked cap design, maybe not. Don't know if they can be machined flat and rehoned. As far as durability in your stroker, you get what you pay for.

If you didn't spin the bearings I'd be tempted to reuse them. If you have no discoloration that's good but I'm not sure discoloration would be a problem. I've had many B/RB rods assembled by using a rod furnace to expand the small end of the rod on a pressed pin assembly. As to cracked cap rods, I thought the only way you could rebuild them was to bore them oversize and use the oversize bearings. As to durability in a stroker, I agree with sgcuda.

What brand are these rods?
Metal is metal, correct?
My message is the rods are machined from unfinished to finished so they been size once incorrectly so why not have them magnaflux to see if they are cracked or not If they magged okay have the bolts replaced and them resize the big end and use them

I wasn't referring to the small end. If the large end is discolored from heat, I would toss it.

I realize that. I was just pointing out that IMHO discoloration is not an automatic reason for rejection.

If they got hot enough to change color then the heat treat is altered. If you have the hardness tested the areas that changed color will be different than the rest of the rod.

Is it worth less than 100.00 a piece to chance it.

Hard to argue with that for a new high hp build.

If they got hot enough to turn color, it’s likely they’ll need resizing(not free), which makes that under $100/ea money a little more palatable.

A color change probably exceeded the anneal temperature, which means the hardness/ductility is affected.
I'd change them.

What you all have said has confirmed what I was thinking.
My first inclination was to toss them and start over.
The only reason I was even considering a redo of the big end was to preserve the balance job on the rotational assembly. I have other options that I may pursue also. Just trying to gather all the information I can to make the most economical and educated choice. The whole once bitten twice shy thing.
Thanks for all the input.

Digger73 (Mike)

I seem to be in the minority but I think an assumption is being made that this particular rod has some type of heat treatment. If you want an accurate answer rather than just opinions, why don't you call the rod manufacturer and see what he says.

The truth of the matter is that I am sort of embarrassed. Due to the fact that I work for a living and have very little extra disposable money flow, I use 440 Source kits. I know I will get all kinds of back lash but it is what I can afford and it allows me to continue to race. I could call them but I am not too sure the rods are even worth any more effort. I take full responsibility for the failure as I was trying something new and am now paying the price for it. I had the rod and main bearings coated with an anti-friction coating. When I assembled the engine the mains were very good on the clearance but the rods were on the tight side. I wanted to assemble the engine and get it in the car so against my better judgement I didn't replace the rod bearings. So I am to fault...

Digger73 (Mike)

Nothing to be ashamed about when Racing on a budget. Thanks to 440source many years ago when they opened up I was finally able to build my first Stroker engine. That engine went 8.60’s@155mph in my Daytona and that engine rotating assembly is still going strong in a street car today.

I agree with John, a set of decently priced quality rod is cheaper than a complete engine.

No assumption.
440 source heat treating discription

No way did they get close to anneal temp if the bearings did not spin
you not all the post heat temp processes they go through
are they still round
torque the bolts down a couple of times with the same lube- do they change dimensions?
mag is not going to show you anything
if a little out of round- which happens to even non hated rods after a few runs
cut the caps flat and re hone
do not worry about the dimension a the parting line it can be a little wide
who makes - actually makes- these rods
no colour pics?

I tend to agree with this to a point but since there is no pic's then this is my opinion,, if there is some minor coloring then they may/probably will be ok to re-use after reconditioning, if they are black then pitch them in the nearest scrap hopper and call the supplier of you choosing.

I stand corrected. Thank you.

Yes they can be .. I just did a set a couple
of weeks ago

Save yourself some grief and buy new ones IMHO.

http://www.molnartechnologies.com/rods-domestic.html

Mine were new H-beam rods but I changed the balance
on the crank so I had to tweak the rod balance and
the small end.. they had been on the dyno for 10
minutes

Thanks everyone for the advise and information.
The flip side of this is that the crank will also need some attention.
So, by the time I buy new rods, engine bearings, crank work and re balance.
I am most of the way to a new 440 source stroker kit. If I go the new kit route I can opt for more compression and more stroke. Just looking for the best option at this time.

Thanks all,

Digger73 (Mike)

When I get home tonight I will get some pictures down loaded of the rods and the bearings.

Digger73 (Mike)

Here are the pictures of what my rods look like now.

Digger73 (Mike)

Heck that didn’t get very hot from those pictures. I would torque it together and check it with a set of mics or a bore gauge.

I dont like that one rod.. has blue about a
quarter of the rod width.. make sure you check
that rod out closely

Definitely, the start of something bad. But, it looks like you caught it pretty early. You should have it checked for stretch. Those rods can be resized on the big end, but I don't know if the heat that caused the blue streak is significant enough to warrant replacement. Check with your machinist. 1 rod isn't a significant expense to save the motor.
More importantly, I think I would be having the crank magnafluxed at this point.

IN GENERAL: Any steel connecting rod will have a heat treatment at some point. As these are 4340 rods I am 100% sure that they, like any 4340 rod, will have been heat treated in a very specific way. When one gets out of the straight carbon steels and into the stronger alloys the heat treat can increase strength maybe 30%. Also each designer will have his own targets for strength and ductility.

Here are temps to achieve different colors. This is by uniform heating and then rapid cooling. This is different from the colors that happen when the steel is heated and held at a specific temp, like "cherry red heat".

1.HEAT COLOURING OF IRON AND STEEL
yellow/228C
brown/254C
purple red/265C
light blue/264C
dark blue/293C

Here is a normal heat treat for 4340:PROCESSING TEMPERATURES
Typical

Forge
2200°F MAX

Normalize
1550/1650°F

Case Harden
1475/1550°F

Anneal
1475/1575°F

Temper
1200°F & 400°F

I started out thinking use them. But, 400F is around 200C so even the least colored rods have been heated past the last tempering temperature. For any kind of high performance work I'd sell them as-is on Ebay and buy new ones.

R.