[67TIGER]

This is my '67 GTO 400 engine. I think these are RPM rods with 7/16 ARP bolts/nuts but I would like to be sure.
I would also need the torque wrench specs for these rods. I really don't think it would be the same as stock Pontiac rods (45ftlbs ?).

Thanks, Hope everyone has a great 4th of July!

[Tom Vaught]

I do not have a comparison picture of RPM Rods but I do have a couple of sets of Earlier EAGLE RODS and they look very similar to the Eagle Rods. Butler has sold a lot of those rods over the years.

Tom V.

[surfsama]

Picture of the RPM Maxxlite rods. The caps look similar but the rest doesn't. There were different versions available so that could be it too.

[steve25]

After snooping around on line they look like Eagle I beam models to me.

[67TIGER]

I really appreciate all the replies, obviously I didn't build this or I would have known what was in it.

What I need to know is what to torque the caps to. RPM w/ARP says 75 ftlbs. while Eagle w/ ARP shows anywhere from 50 to 65 ftlbs (?). I was looking at Butlers site, that is where I found some of these numbers. This is why I'm getting confused!

I'm taking the engine apart to clean everything and replace cam bearings. I will inspect the main and rod bearings and decide what to do with them.

Thanks again for all the help.

[max 93]

Can you use a beam style torque wrench on them to see what they are torqued to before you take it apart?

[67TIGER]

I was thinking about that, I do have a beam style with pointer.

How would I do this though, tighten the nut until it moves while watching the pointer? or watching the pointer while loosening the nut and see where it breaks free at?

I apologize for sounding stupid about this, I have never had to figure out something like this before.

[Tom Vaught]

Originally Posted by 67TIGER

I really appreciate all the replies, obviously I didn't build this or I would have known what was in it.

What I need to know is what to torque the caps to. RPM w/ARP says 75 ftlbs. while Eagle w/ ARP shows anywhere from 50 to 65 ftlbs (?). I was looking at Butlers site, that is where I found some of these numbers. This is why I'm getting confused!

I'm taking the engine apart to clean everything and replace cam bearings. I will inspect the main and rod bearings and decide what to do with them.

Thanks again for all the help.

When I torqued my last set of eagle rods, 6.625 length, I initially did the 50-65 ft lbs number and they did not stretch to the proper number.
I was closer to the 72-75 ft lbs when I hit the required stretch specified.

You just need to get a rod stretch tool and go by that.

Tom V.

[blueghoast]

75 lbs I've used these rods before, Just recently too

GT.

[67TIGER]

I tried the beam torque wrench idea to loosen the nuts. Nothing happened until the pointer got around 75 ftlbs. then things loosened up.

I quickly skimmed the connecting rod page in Rocky Rotellas book and it seemed to confirm the 75# number for ARP bolts.
I'm feeling a little bit more at ease about it now.

A big thanks to everyone for the suggestions, I knew you people would have some good idea's.

Next item coming up in a few weeks: Any tips on installing the Best Graphite rear main seal that the instructions don't mention?

Thanks to everyone!

[steve25]

You need to Torque them up by stretch!

As that's the only way to tell if it's time to replace the bolts which should be done after every 4 Torque up sessions anyway if you do not want to run the risk of spinning a Bearing!

Bolts that stretch to spec slow compared to others are going south, so that's telling you to replace them.
If you use a Beam type Torque wrench you can't tell these things.

[67TIGER]

OK, I have been looking/thinking into this. Do you have a gauge that you would recommend?
Also thinking about replacing the rod bolts, will I need a machine shop to press the old bolts out and the new ones in?

Thank you for the idea's. Keep them coming! I'm getting tired of working on this engine and want it done right.

[Formulas]

Those bolts look ground on the ends .. Balance

[Half-Inch Stud]

Highly massaged SD-455 Rods? or massaged 5140s

Nevermind, the Caps are quite-not what I know.

[mgarblik]

The OP is going to have a bit of an issue to deal with to accomplish what some others are asking him to do. It looks like the majority of the rod bolts have been shortened. 2 reasons I can think of. Clearance issues somewhere or balance, which is kinda weird. The shortened bolts will no longer have the dimple to align the stretch gauge to get accurate readings. So what to do? Removing the bolts to re-spot face them means you would have to recondition the big ends because they would deform removing the bolts. Possibly they could be re-dimpled in a mill with the bolts installed. (that's some set-up and work). You could just replace the bolts, but if ground for balance, now what? You could just measure the bolts for relaxed length if they had not already been ground, so that won't work. So, here we go with the can of worms situation so common on rebuilt engines. If it were my engine and I was trying to put it back in service with the least hassle and cost I would do the following. Try to re-dimple the rod bolts in a mill. (the ones that have the dimples removed) use a combination of an electronic torque wrench and a stretch gauge to see if they reach a given stretch within 5-8ft. lbs. of each other through the set. If you for example stretch 13 bolts to .006 between 71 and 76 ft. lbs., you are good. If three of them stretch .006" at 53-58 ft. lbs, they are soft and need to be replaced. Without replacing the bolts, I can't think of another accurate method.

[Will]

I was going to ask why some of the bolts have been ground. That's weird...

Looks like a factory crank so clearance due to long stroke shouldn't be an issue. That leaves balance, which is a strange thing to do to achieve balance.

At this point, I'd be tempted to replace all those bolts and start over, but things could get complicated if they're pressed pins.

[steve25]

SD 455 Rods they are not since the Rods in his photos are much too narrow in the pin area and do not look to have been machined down either.

Also the notched area on his Rods are on the big end, on SD Rods there on the cap end.

[RAIV55]

Probably too late responding but there are some bolts that have a dimple in them. Could have measured the torqued length, after disassembly measure the torque to duplicate the length.

[Tom Vaught]

Agree, with your post.
Unfortunately the person who did the rod balance job decided to remove those dimples to balance the rods.

And if he then balanced the crank based on that bob weight (Rods, Bearings, and Pistons) then the crank and the new Bob Weight based on the replacement bolts (after the possible re-machining of those rods), would be even more expense.

My vote would be leave it alone and run it unless you are willing to pay to have it Done Right the second time around.

Really sad, and sorry you have this mess to deal with, 67tiger.

Tom V.

[67TIGER]

I have been reading all the idea's and suggestions that have been posted. I too have been wondering about the ground down bolts, doesn't make any sense to me either.

After seeing stuff like this in the pictures, I wonder what else may or may not be wrong with this engine.

I have decided to send the short block out to a professional engine builder (with Pontiac Experience hopefully) and have it all redone correctly.

Replace all the rod bolts, check the main & rod bearings (replace if needed), replace cam bearings. See if there is anything else that isn't right inside.

I want to thank everyone who gave and suggested their opinions. I feel better having other people see what's going on and what needs to be done to fix it correctly.