Severe Vibrations - Harmonic Balancer Problem?? - 350 SBC

[Guest Mike]

I searched and found some threads mentioning this, but I didn't find any that metioned how to test for a bad harmonic balancer.

 

I just bought an Alpha 1 kit car with a 350 SBC and TH400. I can feel vibrations with the engine in neutral/park that feel like a bad harmonic balancer. How can I test for this? There is also a bad oil leak that occurs under WOT. Could the HB have damaged the front seal? The engine poops out at WOT after a few seconds. At first, I thought it was a fuel problem, then maybe carb... but maybe it's the HB??

 

Is it possible this engine is externally balanced even though it's a 350? This was a custom build and I know very little about the internals. Is there any way to test for this... or for other factors, which will affect proper choice of balancer? Is there anything I need to be aware of when choosing a new balancer... brands, quality, better dampening, longevity, price?

[TheNeedForZ]

A bad dampener won't make you feel the engine vibrating, it's something else. The cause could be rough running or one or more cylinders that are not working....fuel starvation? Just my guess.

[BillZ260]

Take it apart and put it back together, seems to work for me...that's what I do when I can't figure something out

[Guest Mike]

A bad dampener won't make you feel the engine vibrating, it's something else. The cause could be rough running or one or more cylinders that are not working....fuel starvation? Just my guess.

 

 

Hmm... fuel starvation... maybe that's why the engine poops out with sustained WOT.

 

I once had a harmonic damper fail badly and it caused this same low frequency vibration related to engine RPM. The vibrations were coming from the damper itself. I installed a new HB and voila... no more vibration.

[Guest Mike]

Take it apart and put it back together, seems to work for me...that's what I do when I can't figure something out

 

I wish I had the time to do that but I don't:rolleyesg Also, this car is substituting for my daily driver while I decide what do do with my old Mazda 626... repair it or junk it.

[Nealio240z]

It could also be that not all cylinders are firing correctly... And check the firing order too... Maybe a fouled plug or wire...

let me know if you find the problem.

[Guest Mike]

It could also be that not all cylinders are firing correctly... And check the firing order too... Maybe a fouled plug or wire...

let me know if you find the problem.

 

Thanks for the advice. The firing order is okay as are the plug wires. This is definitely something different.

[Guest Mike]

Okay... I've been reading about this and I'm wondering if this is my torque converter. Some kind of oil leak appeared at the same time (I think so anyway... I just got this car Saturday). The transmission seems to be shifting sluggishly compared to the way it felt Saturday, so this coincides. The oil seems to be way at the back (I think... I haven't had the car on a lift yet) and travels down the centrally located exhaust, so it could be the converter.

 

What do you folks think... take it to a transmission shop first???

[Paz8]

You just picked up the car on Saturday! go after the seller and make him fix it. If it's showing all these problems now your in for a long hard road. Maybe alittle harsh but the truth.

 

The vibration can be alot of things, motor mounts, trans mount, exhaust system rubbing the underside of the car etc. SBC 350 built after 85' (I think) use balanced flywheels or flex plates as part of the engine balance.

 

The leaking trans is a seperate problem, AT fluid is redish and smells different than engine oil, put some on your finger and check it out. This could also be a simple fix like a leak in the trans cooler line.

 

The WOT problem can be alot of things, fuel filter, stuck choke plate, intake leak, fuel pump, etc.

[specialk]

paz8, why should he 'go after' the seller? Buying a used car is caveat emptor, especially a specialty vehicle like this. It's his, he's got to fix it.

[Guest Mike]

You just picked up the car on Saturday! go after the seller and make him fix it. If it's showing all these problems now your in for a long hard road. Maybe alittle harsh but the truth.

 

The vibration can be alot of things' date=' motor mounts, trans mount, exhaust system rubbing the underside of the car etc. SBC 350 built after 85' (I think) use balanced flywheels or flex plates as part of the engine balance.

 

The leaking trans is a seperate problem, AT fluid is redish and smells different than engine oil, put some on your finger and check it out. This could also be a simple fix like a leak in the trans cooler line.

 

The WOT problem can be alot of things, fuel filter, stuck choke plate, intake leak, fuel pump, etc.[/quote']

 

I bought this car from a guy in NM. I sent him a couple of emails expressing concerns but only outlined serious issues with the body. In essence, he thumbed his nose at me and is posturing up to fight. I don't mind a fight, but I only enter into those I can win. I just don't have time to mess around. I may pay an attorney a couple hundred bucks to send him a certified letter threatening to file a lawsuit in his city/county and remind him that a lawsuit is published in his local small town newspaper. He owns a small business and has many agreements with local schools so this may affect his response.

 

EVRYONE READ THIS... NEVER send more than a few hundred $$$ earnest money. ALWAYS have a reputible third party inspect a car if you can't inspect it personally. ALWAYS use an escrow service. NEVER buy a car if the seller refuses these terms. NEVER trust the seller... NEVER, NEVER NEVER:fmad: This guy gained my trust... not easy to do... and he shafted me:violin:

 

I'll check into all these things. My first stop is the transmission shop where I'll have a built 700R4 installed and repair any leaks at the rear of the engine. Since there is torsional vibration in the drive train too, they'll be correcting any issues with this... incorrect geometry, driveshaft trueness, driveshaft U-joints. U-joint half-shafts will be upgraged to 4-point CV shafts. Transmission mount issues will be resolved during the swap.

 

Regarding type of oil... I haven't crawled under the car yet but It'll be on a lift this afternoon. I've read that a bad torque converter can cause torsional drivetrain vibrations and may leak. The leak is definitely at the rear of the engine.

 

I think you're right about the WOT issue being caused by the carb vac secondaries. At first, I wrote that off because the secondaries move freely under manual operation. However, they seem a bit sluggish with engine revving. Perhaps the cam and maybe small vacuum leaks are affecting its operation?? The entire induction system is slated for a swap anyway. I'm going with a tri-power setup with progressive linkage.

[Guest Mike]

paz8, why should he 'go after' the seller? Buying a used car is caveat emptor, especially a specialty vehicle like this. It's his, he's got to fix it.

 

Yes, "caveat emptor" as always. BUT I WOULDN'T DO THAT TO ANYONE specialk. Would you?! This guy BS'ed me... gained my trust... and this isn't easy to do. The worst part of it is... I WILL NEVER TRUST ANOTHER LIVING SOUL.

[specialk]

I agree 100%. I would never sell a vehicle without disclosing all known problems to the buyer. However, remember what you're buying. A vehicle built from parts gathered together from numerous sources and then handbuilt by someone whom you have never met.

 

Even you said, "ALWAYS have a reputible third party inspect a car if you can't inspect it personally."

[Guest Mike]

I agree 100%. I would never sell a vehicle without disclosing all known problems to the buyer. However' date=' remember what you're buying. A vehicle built from parts gathered together from numerous sources and then handbuilt by someone whom you have never met.

 

Even you said, "ALWAYS have a reputible third party inspect a car if you can't inspect it personally."[/quote']

 

Yup... what gets me though is I gave this bozo my trust... I seldom do that. This goof is VERY GOOD at LYING/BS-ing. I feel like a complete freaking idiot!!!

[dr_hunt]

Where in NM, we need details. I had a similar problem with a trans and a new motor I built, had horrible vibration above 3500 rpm. When we disconnected the torque converter from the flexplate, pushed it back, started the car, the vibration was gone. changed transmissions, vibration went away.

[Guest Mike]

Where in NM, we need details. I had a similar problem with a trans and a new motor I built, had horrible vibration above 3500 rpm. When we disconnected the torque converter from the flexplate, pushed it back, started the car, the vibration was gone. changed transmissions, vibration went away.

 

This guy is in Los Alamos, NM. I was somewhat abrupt in my second email to him, but never abusive. In his reply he essentially told me to F.O. and he replied with more lies. I have all email correspondence to prove it.

 

My first stop is the tranny shop, where I'll inspect it on their lift, list everything I need for the 700R4 swap, then get it done. They're also going to check for driveline geometry issues.

 

BTW, any recommendations for a shifter? The one in the car for the TH400 sucks... no safety stops and no 1st gear position. Please keep recommendations reasonably priced.

 

Wish me luck!!

[dr_hunt]

Ebay for a shifter. I have the hurst quarter stick, three of them actually. Two for the glide and one for the th350. I'd rather have another shifter for the three speed, one that is a true ratchet shifter.

 

If it's severe it would be flywheel trans related although I lost a balancer once, it vibrates alot without one, but that is without one. If yours is still on I'd suspect the wrong flywheel or what I've run into with the trans.

 

This guy is in Los Alamos' date=' NM. I was somewhat abrupt in my second email to him, but never abusive. In his reply he essentially told me to F.O. and he replied with more lies. I have all email correspondence to prove it.

 

My first stop is the tranny shop, where I'll inspect it on their lift, list everything I need for the 700R4 swap, then get it done. They're also going to check for driveline geometry issues.

 

BTW, any recommendations for a shifter? The one in the car for the TH400 sucks... no safety stops and no 1st gear position. Please keep recommendations reasonably priced.

 

Wish me luck!![/quote']

[Guest Mike]

Ebay for a shifter. I have the hurst quarter stick' date=' three of them actually. Two for the glide and one for the th350. I'd rather have another shifter for the three speed, one that is a true ratchet shifter.

 

If it's severe it would be flywheel trans related although I lost a balancer once, it vibrates alot without one, but that is without one. If yours is still on I'd suspect the wrong flywheel or what I've run into with the trans.[/quote']

 

How do you like the Hurst quarter stick? I want more functionality and saftey than I have. This one will push straight into reverse with no safety lock snd it will manually downshift only to second gear.

[dr_hunt]

It has the function and the neutral safety switch as well. What I don't like is having to squeeze a lever before shifting from second to third, then if something jars you like a hard shift, you can then bump it into neutral. Reverse is locked out well.

 

It's a great powerglide shifter though. I get them for about 80 to 120 bucks complete, one was NIB for 90 bucks.

[specialk]

In the extremely custom car world, these sorts of people are an unfortunate side effect. These folks do not have morals, they're just trying to find a way to unload their problems on someone else. The good news is that you can spread the word about these cheats and stop them from whacking other people in the future.

 

Good luck, I hope you get everything going well in the VERY near future.