[scott70]

I may have my engine rebalanced this winter and was thinking about the rods while we’re in there. Back in 2012 I think I had the engine gone over and bought rods from ace Ken ppr .I don’t have the paperwork but I think they were a step up from stock. They are the I beam design with pressed pins. I shift it at 5500 and was wondering if I should step up to some scat H beam with spiral locks. When I bought them I remember you could spend more and get a better grade I beam material but I went with these after he said these were definitely better than stock rods.

[steve25]

Even if you were now going to shift now at 6400 rpm there’s no need for better rods .

If you want more of a safety margin out of those rods then have stronger rod bolts installed and then resize the rods as needed.

[scott70]

Yeah, I’m not sure what’s in it for Rod bolts. I would’ve hoped that they were a decent rod that they would’ve come with ARP’s.

[hurryinhoosier62]

Originally Posted by scott70

Yeah, I’m not sure what’s in it for Rod bolts. I would’ve hoped that they were a decent rod that they would’ve come with ARP’s.

Most of the rods Ace sold had ARP bolts installed. “I” beam or “H” beam rods?

[scott70]

I actually found some pics from like 6 years ago when the engine was apart . I don’t see any markings on the rods but in one pic I can see arp on the bolt head. Should be ok for what I do? Obviously they’ve hung in there since 2012 but I was just thinking if it really should have a better rod? Maybe not? I just don’t know what they really are as far as quality.

[Tim Corcoran]

Why are you having the engine reballanced?

[scott70]

Ugh. My engine was balanced to my oem flywheel. Then last fall I installed a tkx trans, new billet neutral balanced flywheel and a supposedly neutral balanced clutch. I had the new flywheel balanced to the same imbalance of the oem flywheel. And the clutch/pp was out of balance but supposedly in the end it all balanced out to what I had. On start up it felt like it was shaking more than I remembered and cruising down the road there was a buzz in the steering wheel. Experimenting I removed the weight they had added to the flywheel. Cruising now was noticeably better but not perfect and idling it still feels like it shakes more than it used to. I’m replacing the new clutch this winter because it chatters and is not getting any better. I would feel better knowing the motor is balanced in a way that I can use a neutral flywheel and clutch and have it work. Maybe a bad idea but I want it right. Now with a new clutch would they balance it to the oem imbalance that didn’t work or just throw the new clutch in and hope for the best? I figured since I’m pulling the transmission anyways instead of fighting underneath the car I would just pull the whole motor and trans out together and then done the way I think it should be. If I wasn’t putting a new clutch in I would leave everything the way it is,,, it’s doable. But since I’m getting into the clutch again and possible more out of balance I don’t want to take the risk. I’m getting tired of taking heavy stuff apart under the car. I’m not 25 anymore.

[Formulas]

As far as rod bolts go , .... Those are at least the lower grade 8740 ARP bolts, ..... And as a unit your rod and bolt combo are far stronger than a stock cast rod, ... I would leave them alone unless you find something alarming on tear down, ... You cant fix what isn't broke but it can sure get screwed up trying..

Btw ... you had a destructive level pressure spike on that rod bearing at TDC

.

[steve25]

I bet that upper bearing does not snap into the big end anymore!

That’s a definitely a sign of detonation .

What cylinder was that out of?

[mgarblik]

I think material wise and hardware wise, those rods are just fine. I would remove all the bearings, use the proper lube, torque the fasteners, and have the big ends measured for size, taper and out of round. My guess is they will find the big ends are out of shape and spec., looking at the one bearing pictured. Have the big ends re-sized if necessary, and put the engine back together. A shop that is capable of doing this should be able to accomplish this without removing the pistons. From what I can see, they look like press-fit pins.

[scott70]

The pic of the bearing was from like 6-7 years ago . Since then it’s had all new bearings,,, .0022 rods and .0025 on the mains I think afterwards and supposedly everything checked. Oil filter has been looking ok on oil changes. We thought of detonation at the time… ra4 sized cam, roads vmax lifters, 33 total timing while running a mix of 93 and 100 av fuel at 9.7 comp. I don’t know why it would ever detonate but it looks like it was. Engine has been together for years now so what the bearings look like right now I have no idea.
So it sounds like the current rods are just fine.
And the whole balance thing is why I’m thinking about opening it back up again. I’d like to be able to put neutral balanced stuff on and not affect the balance.Just installing a new clutch and hoping for the best is not my preferred path. Matching the oem fw imbalance to the new setup should of worked but it didn’t.

[mgarblik]

Originally Posted by scott70

The pic of the bearing was from like 6-7 years ago . Since then it’s had all new bearings,,, .0022 rods and .0025 on the mains I think afterwards and supposedly everything checked. Oil filter has been looking ok on oil changes. We thought of detonation at the time… ra4 sized cam, roads vmax lifters, 33 total timing while running a mix of 93 and 100 av fuel at 9.7 comp. I don’t know why it would ever detonate but it looks like it was. Engine has been together for years now so what the bearings look like right now I have no idea.
So it sounds like the current rods are just fine.
And the whole balance thing is why I’m thinking about opening it back up again. I’d like to be able to put neutral balanced stuff on and not affect the balance.Just installing a new clutch and hoping for the best is not my preferred path. Matching the oem fw imbalance to the new setup should of worked but it didn’t.

Sorry for my misunderstanding. I got off in the weeds looking at those pictures.

[hurryinhoosier62]

Originally Posted by scott70

I actually found some pics from like 6 years ago when the engine was apart . I don’t see any markings on the rods but in one pic I can see arp on the bolt head. Should be ok for what I do? Obviously they’ve hung in there since 2012 but I was just thinking if it really should have a better rod? Maybe not? I just don’t know what they really are as far as quality.

Those resemble the 5140 alloy rods Ace sold. He also sold 4340 rods but they were “H” beams. As many have already said, replace the bolts and have the rods reconditioned. I would add to have the rods magnafluxed as well.

[scott70]

Originally Posted by hurryinhoosier62

Those resemble the 5140 alloy rods Ace sold. He also sold 4340 rods but they were “H” beams. As many have already said, replace the bolts and have the rods reconditioned. I would add to have the rods magnafluxed as well.

These are probably the 5140 then. I do remember 2 different numbers, those are probably it. Replace the current arp bolts?

[Skip Fix]

I think I have a brand new set of those in the attic-still in the box from ACE! I can look at them for the bolts if you want.

[scott70]

Originally Posted by Skip Fix

I think I have a brand new set of those in the attic-still in the box from ACE! I can look at them for the bolts if you want.

If you would like,, don’t bother going to a bunch of trouble to dig them out. Wouldn’t the arp rod bolts in my rods now be ok? Are people saying upgrade to a better arp bolt?

[BLUE TA]

I have some 4130,s I bought from ace. they look alot like the op,s BLUE TA

[PunchT37]

Originally Posted by hurryinhoosier62

Those resemble the 5140 alloy rods Ace sold. He also sold 4340 rods but they were “H” beams. As many have already said, replace the bolts and have the rods reconditioned. I would add to have the rods magnafluxed as well.

I have some 4340 I beams from Ace. Full float.

[Squidward]

Originally Posted by BLUE TA

I have some 4130,s I bought from ace. they look alot like the op,s BLUE TA

That's what I have in my 350 right now. I have the 5140's in the 400 in my Lemans.

As a side note, it has been a lot of years since I put that motor together. Does anybody know the torque specs for these 4130 rods?

[steve25]

A 3/8-24 bolt of the likely grade ( like a S.P.S ) would have an applied torque value of 47.5 to 54 ft lbs and a stretch of .0055” to .0065”.

If the bolts have the dimples for using the stretch method you should really consider doing it that way especially since this I guess will be the 3rd time there being pulled up.