Bad vibrations

[68 HEMI GTS]

Spent the last 6 years or so collecting parts and building my hemi. As most know, these things aren’t cheap so it takes time. Finally got it all assembled last winter. Ran it on the dyno in January but had some issues with a vacuum leak on the cross ram. Tossed an old unported Barton single plane on and also had issues with sealing that (has some whimpy center section the deflects) and I didn’t have time to let the silicone cure. Anyway, I only got to make 2 real hits on it, one up to 6500 with a 1050. Resealed the ends again and tossed my 1150 on made 1 pull to 7k. Made 818 with zero tuning basically so I was pretty happy (for a pump gas engine). Didn’t really notice anything funky with the engine on the dyno. I dropped it in the car and soon as I rev’d it up I knew something was bad wrong. Doing some quick math I was pretty sure I knew what the problem was. Pulled the engine out this week and tore it down. Sure enough my hunch is correct. Now I bought the whole rotating assembly from a reputable source (which I’m not going to name). Paid extra for the balancing. Now shame on me, I use to do this kind of work for a living. When I pulled the crank out of the box it struck me weird how much weight was removed being a hemi. I just didn’t take the time to really process what I was looking at at the time. Well after running the numbers, it’s 229 grams under balanced on the bob-weight. I feel fortunate we didn’t get to make a bunch of pulls on it now, thinking it may have self destructed as bad as it felt in the car. We will see how they do, I’m not real happy. I’m out time, gaskets, rings, and I feel like the crankshaft is going to be a mess adding all the Mallory into it compounded with all the drilling they have done to it. Guess we will see. Their bobweight Calc was 2199, which is correct if it didn’t have wrist pins, rings, locks, & oil support rails

I have the ability to weigh parts so I did. Surprised it didn’t trash the bearings.

On the dyno


In the car

 

[Aron Gleason]

Sorry to hear about your dilemma. Hopefully you can salvage most of the engine parts. I think I saw your road runner in a YouTube video. Sounded really good.

 

[Curiousyellow71]

It's going to be a awesome ride. Second thread as of recent where a new build was vibrating. I have noticed under power and idling engines out of balance didn't vibrate..but shook bad at speed. It would be hard to catch that on a dyno.

 

[Fran Blacker]

Whoever you bought the rotating assembly from are they going to make it right?

 

[MarPar]

 

[steve340]

I hate it if I have to do things more than once - but I have quite a few times over the years.
The engine sounds really good so once you sort the balance factor out it will be fine.
Good luck.

 

[PRHeads]

Wow!!

I’m sure you’d really like a new crank balanced correctly from scratch. I would too.
Doesn’t sound like that’s what you’re expecting though.

And gaskets, sealants, dyno expense, etc.

 

[Fran Blacker]

Anyone notice unusual air traffic like after 9/11? Had lot of unusual traffic here in my area of CT.

 

[68 HEMI GTS]

Wow!!

I’m sure you’d really like a new crank balanced correctly from scratch. I would too.
Doesn’t sound like that’s what you’re expecting though.

And gaskets, sealants, dyno expense, etc.

Exactly what I would prefer. I feel like adding 230 grams to the counterweights of this crank is not ideal. Makes you angry when you pay good money for something and it gets screwed up in the process. Guess I’ll see what they have to say when they see it. They offered to rebalance it if I bring it to their shop.

 

[Aron Gleason]

Makes me wonder if it's a paperweight since that much weight was taken out.

 

[RemCharger]

I don't see how putting the weight that was removed , back into the crank is a problem?
In the end, balanced is balanced?

 

[Budnicks]

wow 229 grams, that's not a lil' mistake
someone blew it in their math for bob weight/balance

good luck
sorry to hear you had this issue too, sucks donkeys ***

can't wait to see the videos & runs after

 

[68 HEMI GTS]

Wow!!

I’m sure you’d really like a new crank balanced correctly from scratch. I would too.
Doesn’t sound like that’s what you’re expecting though.

And gaskets, sealants, dyno expense, etc.

Quick update to my saga. They balanced the crank and sent it back. Needless to say I was less than impressed. No filler rod used to weld weight in. Crack on the counter weight as well as the welds.. not something I’m going to put in my 7k 800hp hemi…

After lots of deliberation I now have a new crank in my possession. Some pics of the hacked re-balance.

 

[khryslerkid]

Looks like no preheating before tig welding.

Glad to hear you got another crank.

 

[68 HEMI GTS]

Looks like no preheating before tig welding.

Glad to hear you got another crank.

Yeah, they went as far as having the guy who welded it call me and tell me he’s been doing this for 30 years and it’s perfectly fine. Then it was send it back and we will re-weld it. Needless to say I struggled to maintain any sort of composure.. lol

 

[khryslerkid]

Yeah, they went as far as having the guy who welded it call me and tell me he’s been doing this for 30 years and it’s perfectly fine. Then it was send it back and we will re-weld it. Needless to say I struggled to maintain any sort of composure.. lol

You think after 30 years he would have learned to weld?

 

[fourgearsavoy]

You think after 30 years he would have learned to weld?

Never too late to learn how to do it right.

 

[1 Wild R/T]

I don't see how putting the weight that was removed , back into the crank is a problem?
In the end, balanced is balanced?

If it were your hard earned money that you spent on a new rotating assembly would you be a happy customer when your crank showed up looking like the same used up, patched up stuff you were trying to avoid by buying new parts?

Quick update to my saga. They balanced the crank and sent it back. Needless to say I was less than impressed. No filler rod used to weld weight in. Crack on the counter weight as well as the welds.. not something I’m going to put in my 7k 800hp hemi…

After lots of deliberation I now have a new crank in my possession. Some pics of the hacked re-balance.

View attachment 1566382View attachment 1566383View attachment 1566385View attachment 1566389

68 HEMI GTS
You sir are showing great restraint.... Still haven't put a name to the company that hasn't made it right...

 

[steve340]

I am no fan of weights welded in like that. The centrifugal force throws them out and the do around the same damage to the engine as an artillery round.
Those cracks will often occur when welding dissimilar metals and cooling to quickly and not keeping the inert gas after flow going.
You would think they should have added some Mallory to the counterweights.

 

[68 HEMI GTS]

If it were your hard earned money that you spent on a new rotating assembly would you be a happy customer when your crank showed up looking like the same used up, patched up stuff you were trying to avoid by buying new parts?


68 HEMI GTS
You sir are showing great restraint.... Still haven't put a name to the company that hasn't made it right...

Nope, don’t want to name the company. Just more less venting my frustration..