ARP bolt question

[NoMope Greg]

For years, I've been reading about the advantages of ARP bolts.  For a street motor that may see an occasional blast down the 1/8th (or ricer kill), is it worth the extra money to buy new ARP bolts to replace the stock bolts?  Frankly, the machine shop already fit the rod bolts to my rods and the old stock main bolts are in place.  I'm going to get new head bolts regardless - the old ones are rusted and I'm not sure I have all of them anyway.

 

[Moparal]

If you get new bolts, it is recomended that the rods be rehoned with the new ones. Line bore too. But I have did it without before with no problems. New rod bolts are always good to do , especially if it's a race application

[moper]

The books say if you change the fasteners, you must re-machine. It doesnt affect two flat surfaces like a head surface. but any round bore does distort some when properly clamped by better fasteners. Rods distort a lot more, because it'sa much smaller cross section of metal. Main caps usally do too. Whether it's enough to damage anything is another matter. I did it once without it. Never again.

[NoMope Greg]

OK, thanks for the advice.     Now that I think about it, they did call and ask if I wanted it line-honed and I said yes.  Since that was done with the original fasteners (and the rods resized with the fasteners that are in them), I'll stick with what's there.  All that, plus you guys saved me $100. 

[71chally416]

I take it you have some other new rod bolts besides ARP? I would NEVER build a perfomance engine and use the stock 30-40 YO rod bolts. You can actually feel the difference between a stock rod bolt and a good one when you torque them down. They will be the first thing to fail. Usually they stretch out when stressed and then a nut backs off and falls into the pan followed by catastrophic rod failure when the cap comes off. That's not the place to skimp and try to save money.   

[NoMope Greg]

Well, here's my dilemma.  The machine work is done and the block is on my engine stand.  The rods were resized and new nuts were fitted, but not new bolts.  The machinists are highly experienced - one of the better known performance machine shops in my area.  He's already pointed out a few extras above and beyond my original order that provided an increased return on investment.   In my guy's opinion, the bolts were still in good shape.  I admit my own ignorance in this matter - I'm going on his word.

A little about the engine build.  It's a 440, .040 over, forged crank,  KB hypereutectics, 9.0:1 compression ( fairly low, I know.)  Rods are LY Six-Pack rods (do I need an external balance damper?)  Heads are the old DC Stage IV 476 iron open chamber 88cc, 2.14/1.73 with stock rockers.  Intake is the Edelbrock CH4B dual-plane (both heads and intake were on the engine when I bought the car and my current budget says they're staying for now.)  I'm planning on using a Lunati VooDoo 60303 cam (adv. duration 268/276, duration @ .050 226/234, gross lift .494/.513, LSA/ICL 110/106).  I'm still a little up in the air about carb - probably an Edelbrock Performer 800, but maybe a Holley Street Avenger 770 - and ignition.  Trans is an A-833, so no converter to consider.  As I previously stated, I don't anticipate beating on this engine on a regular basis - more a cruiser than a bruiser.

Following the advice offered here, in order to do things for maximum reliability, I need to have the rods sized and the block honed using the bolts I'm going to use in the engine.  Unfortunately, I'm obviously asking this question too late, so what I need to know is do I stick with the bolts I have that the block and rods have already been sized to or do I buy new ARP bolts and refit those to the block and rods as they are.  I realize I could buy new bolts and take everything back to the shop and ask that everything be rehoned, but that ups the cost by about $300+ ($100 for bolts and $200+ for machine work.)  Is it worth it?

[71chally416]

Maybe the bolts have already been changed in the past, who knows. But me, I'd never trust bolts that are at least 37 years old (if they are OEM) on those gigantic 6-pak rods with a big ugly pistons like a 440 has. It's alot to ask of the bolts to be stressed with all that weight and be thermally cycled hundreds of times over that many years. Most people think they should've used 7/16" bolts in those big heavy rods anyway. I'm not impressed with a machinist that would even resize rods with the OEM bolts (if that's what they are) Of course they "look OK"  It's a bad gamble to save $58 http://chucker54.stores.yahoo.net/arpbrb392hem.html

Get on the phone and tell him you're only gonna run the motor if he
guarantees in writing you never have an engine failure because a rod bolt breaks or rod nut backs off from the bolt being stretched. I.E. - if you pitch a rod and find a rod nut laying in the pan, it's on him.  I'll bet he declines..... 

[nivvy]

Rod bolt stretch should ALWAYS be checked........ 

[Moparal]

As far as machine honing rods, it is only around 5 to 8 bucks a rod to do the big end.  With those heavy rods and light compression, you will not have a big hitter engine anyways, You may be ok driving your car as a regular hot rodder. But I wouldnt be racing the engine. Did you internal balance it?

[moper]

Your machine shop stinks if they see a 6pack rod with a huge heavy cap and beam, and leave the samll used bolts in it. Sorry to disagree with them. I would pull them out, and change the bolts and have them resized. It's not the best rod for the job anyway, and the weak point is the bolt...

[71chally416]

That's ezacly the way I feel. 

[NoMope Greg]

I talked with the machinist and we apparently miscommunicated, primarily through my own ignorance.  He was under the impression that I had planned on a basic stock rebuild and apologized to me for not asking me about the rod bolts.  I think that the fact that there was an almost five month delay between the time I dropped the parts off and the time I picked them up (waiting for pistons that never came) may have played a part in the confusion.  He did suggest several things during the machining process (all of which I agreed to) and simply neglected to ask me about the bolts.  He indicated that they would be willing to work with me towards refitting upgraded fasteners.  

Frankly, I accept his explanation and still trust their work.  As I said, this is a long established shop with an excellent reputation.   The founder, Ed Hale, was the winningest driver at the local short track (Cajon Speedway.) He built all his own engines, engines for many of his competitors and innumerable engines for local drag racers .  He passed a few years ago, but the guys working for him continue his high standards.

So, I'm going to take the rods back and have new bolts installed and all the rods resized again.  Given that this engine will rarely see the far side of 5000 rpm (maybe even 4000), is it worth the extra money and hassle to take the block back and do the mains?  I understand that for maximum reliability that I should do so, but what is the likelihood of failure with the old bolts?

Thanks again to all of you for your help.  I'm learning a lot.

[71chally416]

The main caps are a different story than the rods. They usually have to be dislodged with a rubber mallet to even get them loose with the bolts removed because they fit tightly in machined steps in the block. I see no reason why you couldn't put new bolts or studs in them without re-machining. I've done it many times. If you're concerned about that then install all the new bolts or studs and see if the TQ to turn the crank alone has changed any. Check it before changing them with an inch-lbs TQ wrench and then after. If it's exactly the same then nothing has moved. I've never seen a Chrysler motor that even needed align boring. If the machine work is poor you'll do more harm than good. As long as the crank spins freely with the mains torqued down and you have the proper bearing clearances, don't worry about it.

The rods caps on the other hand are positioned onto the rod by the rod bolt shank itself. A whole different story. 

[heminut]

The main caps are a different story than the rods. They usually have to be dislodged with a rubber mallet to even get them loose with the bolts removed because they fit tightly in machined steps in the block. I see no reason why you couldn't put new bolts or studs in them without re-machining. I've done it many times.

The rods caps on the other hand are positioned onto the rod by the rod bolt shank itself. A whole different story. 

  I've never rebuilt an engine without putting new rod bolts in and having the rods resized, cheap insurance IMHO. I did put main studs in my 392 and didn't have the block align honed and have never had a problem with it, and I've really hammered on it!

[moper]

I would leave the mains just as they are. Old main bolts get re-used all the time, and as you say, the use is mild. The rod bolts fatigue over time and use. Those I WOULD remove and have addresed. They slip right out. No harm done. No circle track builder in the NE that wins would re-use old original rod bolts. It's good that you like them, and that they'll work with you.  Everyone has their opinions and limitations. Maybe in the future, just pay more attention now that you know more things to look for. they sound like good guys.