600 ft GRP Rods

Greg, I have no idea if it holds true for anything other than MGP, BME and GRP rod bolts. All three give that same instruction so I wouldn't say it's a fluke. Maybe has something to do with the ceration fit.....??

I also tighten by hand with a T handle where there's no room for movement. Then torque with one pull making sure I have no obstruction.

Greg, you gonna have your car ready to run with us (Top Eliminator West) in June?

Blessings.........Ron Clevenger.

 

Good question Greg,

The only thing I know is that on a head, manifold, etc it will certainly cause distortion of the part, that is the reason for not torqing in one step. As far as the rods go I assume the guys that make them know what they are talking about and that the distortion is not an issue, as far as mains you generally have a lot of material that is not under the bolt being pulled together by the bolt, in addition most bolts are either 4 bolt or side bolted so the block and cap probably squirm during tightening of subsequent bolts.

But I aint no enginear or whatever you call those guys who make the big bucks

RG

 

How about the Snap On digital torque wrench ? , mine's pretty new but do they go out of calibration as quickly as a mechanical one ?
Oh Will my pushrods arrived through the post safely, thanks for offering to bring them over for me

 

When I told Bill Miller we used the red line assembly lube he said that was fine just be generous with it (all over the bolt, top and bottom of washer and lube up cap and rod threads). He didn't seem to favor just trusting the engine oil (between rounds) on the rods considering how it's not anymore effort to use a good lube.

Eli; Since it was a pretty lenghty conversation I didn't try to capture it all in a short post. For my deal ( BBC with oversize washer and "fuel" bolt) he said to put 100lbs on the first rod then check the stretch as it should be real close. If it's a little short then bump it up 10lbs till you get where you want to be. After that you have your reading for the next 7 in single pulls. But then again, measure after each rod is torqued.

 

Giannone (MGP) says to use 50 wt conventional racing oil generously, which I do.

I still have my old instructions for BME. Miller says to "use only a high quality racing motor oil for assembly purposes" It goes on to say "Snug bolts down and tighten to the following recommended torque in one smooth pull. Do not tighten in steps; this can produce improper bolt elongation and reduce clampling force!"

I don't have any instructions on hand for GRP for lube but I would think it would be along the same line as MGP and BME.

I also did it in steps for many years until I started running the MGP's and Giannone was pretty bold in following his procedure. Like I learned some years back, some things are true wether you believe them or not. So I figured they were designing and producing the rods, not me.

Blessings.........Ron Clevenger.

 

So Ron, are you saying you worship your PRO CHARGER?

 

Will,
I greatly respect your opinion, and it was not my intention to trash anyone or point fingers. I should have left the manufacture name off but emotions were running high. The main reason for the post was to gain some insight on a probable cause. There is a vast knowledge base here with people doing this longer than I've been alive. I think there were some great issues raised here with a lot of experienced people weighing in.

Here is what I have found so far. My torque wrench is 1.5 lbs off @ 90 LBS, the bearings look new ( rods & mains) even the one's that were mashed had no visible signs of an oiling problem. What does that leave us? A bolt not torqued, possible. But you can't say that every rod manufacture produces a perfect rod every time! Material quality, bolts, heck the amount of coolant used in the machining process all effect the end result. We have sent a brand new set of rods back because of poor thread fit. Mistakes, oh yea I've made my fair share and then some, but a 10k burnout, come on.

 

Some day I'll tell you about the time we spit a rod cap through the bottom of the pan while warming it up in the pits.

Poo Poo happens and you move on.

.

 

Ron, everyone, good point about the mains, etc, moving around while tightening. I was just curious.

Ron, I'll be at the track, but my little mouse doesn't have the steam to run anywhere close yet. I'm running a few NE1 races this year to get laps in the new car. The weekend before your race, i'll be racing in Bakersfield.

 

Engine Failures

Guns don't kill people.....people kill people?
Rods don't' break.....people break rods?
99% of engine failures are human error IMO
Guess I am getting more cynical the older I get ( LOL)

 

FYI:

I was finishing up some barrel valve spools I modified and was checking the stage GPM in the pits after we lost on a Sunday at Pomona. The engine was serviced and ready to go. On the third start up I had my driver hit 6,200 RPM again so I could do a computer dump and that's when it kicked the #2 rod cap through the pan.

When we dropped the pan we had a complete rod bolt laying in it with aluminum spring-like material wrapped around the threads. The other rod bolt was bent in the middle where it broke. When the rod cap was put back on (what was left of the rod) there were enough threads still in the rod to tighten up the rod bolt. The upper rod bearing looked like brand new except it was folded in the middle. Pretty easy to figure out what happened.

I had Brian at GRP look at the broken rod but I already knew what happened. In 1,000 pan drills you gotta give your bottom end guy at least one.

RG

.

 

600 ft rods

Hi Guys
Sorry I didn't see this post earlier. What I mean by the aluminum threads being stronger than the bolt is in a static not a cyclic load (fatigue). Take a old rod , chuck it up in a vise , get a big guy with a long beaker bar, tighten the bolt until something breaks, The bolt will break before it pulls the threads in the rod. On the other hand, in a cyclic load the aluminum threads will fail 1st because the fatigue life in the steel is greater the aluminum. The trick is to stop the cyclic loading by havings enough clamp load on the bolts to overcome the tension load pulling on them. A bolt is just a really stiff spring, when we stretch it X amount it pulls back with Y force. Our L-19 bolt stretched to .007" will have 18,000 lbs of clamp force, 36,000 lbs for the 2 bolts. Thats 18 tons! A typical TAD or TAFC will have 25,000-30,000 lbs of pull on the cap at 10,200-10,500 rpm. If the clampload holding it together is greater than the tension pulling it apart the bolt will not move and fatigue the threads in the rod. When we torque a rod we are trying to make an educated guess of what the stretch will be based on the friction of the components. There are alot of variables like lube, torque wrenches, tightening cycles, bottom end technitions. We have been recommending varifying the torque value with bolt stretch because it equalizes the variables.
In my opinion a Walmart torque wrench is as good as any if you check your results with a stretch gage. Something else I have learned is that you cannot accurately diagnose rod failure over the phone or on a online forum without seeing the broken parts.


Brian Scollon
GRP Connecting Rods

 

Hello Brian,

Thanks for the reply,


I am curious how many times you can generally torque/stretch an L-19 bolt properly before the bolt needs to be replaced. I assume that when you stretch the bolt .007 you are exceeding the true elastic point of the material and that some measurable strain remains, how much deviation from original length is acceptable? or do you recommend another method to determine when to replace them?

Thanks in advance,

Richard Gavle

 

on backwards

On putting the cap on backwards Do some of you guys stamp a number on one side of the rod and cap? I know some fuel teams do it, So If you do not have to numbers that match you know the cap is turned around. like for example 05 to 05, 00 to 00 so forth. Im glad this post was put on here, to me this subject is at the top of anyones list. Thanks for the info.

 

600 ft rods

"I am curious how many times you can generally torque/stretch an L-19 bolt properly before the bolt needs to be replaced. I assume that when you stretch the bolt .007 you are exceeding the true elastic point of the material and that some measurable strain remains, how much deviation from original length is acceptable? or do you recommend another method to determine when to replace them?"
Thanks in advance,
Richard Gavle

Hi Richard
I'm having one of my guys testing this right now. He's on 56,382 times before his arm fell off. Seriously, .007" is a little over 75% of yeild so we are not into the plastic range of the bolt. The bolt should always outlast the aluminum rod.

Brian
GRP Connecting Rods

 

Hmmm.... Good thing we have a tech section.

What 99.9% do it take an electric pencil and write the cylinder number on the side of the cap and the side of the rod. That way when your bottom end guy drops eight rod caps in the tray under the engine between rounds there is no question which one goes back on what rod. You do know you can't swap rod caps around to different rods, I hope? I don't like smacking the side of anything with a number stamp so I don't use them much.

I'm kind of a lame person, so whenever I mark the rod numbers (which coincide with the cylinder number) I always mark the side that has the slot cut for the bearing tang. That way when I am hanging rods and pistons I can quickly double check my work by looking at the rods once they are installed in the engine. The tang side faces out toward the pan rail of the side you are working on, and so should the numbers. If you don't see a number you screwed up.

Because we have multiple sets of rods and multiple rod length sets we use depending on where we are, sometimes I engrave a small letter on the rod and cap, too. Like 8a, 7b, 4e. That way if we have several sets apart and two accidentally end up in the solvent tank I don't end up putting number one rod cap from one set of rods onto number one rod from another set.

Engine assembly 101, I know. But, like I said...this is why there is a tech section.

RG

 

Thanks for the reply Brian,

I had no idea that .007 is that far from plastic, I guess thats why they cost more than grade 8

R/G