Looking for input on my engine vibration issue.

[mburger]

Hey everyone.

Once again I'm looking for input from those that know way more than me.

Problem:
347 Stroker with about 6k miles. Blueprint long block with Pro-Flo 4.
Engine dyno'd at 439hp/429tq. Started vibrating. One day it was ok, the next it was vibrating.
It vibrates throughout the RPM range, however, it is worse at about 1,700 - 1,900 and then again at 2,500, then it'll get a little better before getting progressively worse heading towards 4k.
It vibrates sitting in the driveway with the clutch in. No difference when driving.
The engine is running well otherwise.
If something worked, then it doesn't, something changed. Has to be. But what?

What I've done:
Started a warranty file with Blueprint. This is their long block.
Blueprint says it is not their long block because they can't think of anything in the long block that would make the engine vibrate.
If I push it, they'll likely take it back to test and then rebuild. I'm not wanting to do that due to the work involved and I won't see my engine back for many months most likely.
I sent my flywheel at their insistence to be checked that it is within 2gms of 28oz. If it isn't, they will make it so and send it back. (I have no use for it now)
Replaced the Energy Suspension Poly engine and transmission mounts with rubber OEM mounts. No difference and I hate them.
Replaced the flywheel from Mike Forte.
Replaced the balancer with a Fluidampr 650211.
Replaced plugs, wires, rotor and cap.
Replaced the Pro-Flo 4 ECU.
Sent pics of plugs to Blueprint and they verified looked good.
Verified timing with cylinder #1 rocker arms TDC.
Ran the engine with ONLY the balancer and flywheel - no serpentine belt. STILL VIBRATES.

Yes, I know it looks like I'm throwing parts at a problem, but some parts I already had, others were at the direction of Blueprint and some were out of sheer frustration, like the ECU, which I returned.

I am at a loss. I'm missing something. What else can I check?
I have not done a compression test recently, but I did when the engine had less than 1k on it, so I have possibly a break-in comparison. All cylinders were within 5%.

What say everyone?

[Sdonnel]

Might be a long shot, but did you dial in your bell housing? I don’t think the vibrations you are feeling would be caused by that. Just an idea. I had a vibration at 4,200 rpm and redialed the bell housing to .0005” and it’s gone. I hope you find it quickly. I chased mine for a while.

Scott

[BadAsp427]

Check and see if your side pipe supports are up against the bottom of the body under the doors. I had that problem with the FFR brackets... they were touching very tight up against the body/frame... As soon as I put a piece of rubber (heater hose) between the body and that bracket and the vibrations were gone.... My main RPM range was 2200-2700 rpm...

[mburger]

Might be a long shot, but did you dial in your bell housing? I don’t think the vibrations you are feeling would be caused by that. Just an idea. I had a vibration at 4,200 rpm and redialed the bell housing to .0005” and it’s gone. I hope you find it quickly. I chased mine for a while.

Scott

Thanks Scott. Appreciate the suggestion!

[mburger]

Check and see if your side pipe supports are up against the bottom of the body under the doors. I had that problem with the FFR brackets... they were touching very tight up against the body/frame... As soon as I put a piece of rubber (heater hose) between the body and that bracket and the vibrations were gone.... My main RPM range was 2200-2700 rpm...

Hey Carl.
I double checked and the hangers are about an inch below the body’s edge. Thanks!

[Gordon Levy]

Is the vibration rpm specific? If yes at what RPM

[mburger]

Hey Gordon!
It vibrates throughout the RPM range, however, you really feel it about 1,700 - 1,900 and then again at 2,500, then it'll get a little better before getting progressively worse heading towards 4k.

[bobl]

Here’s a trick that may help with your diagnoses. Place a clear cup of water on the engine. The water will oscillate when there is vibration. (If it vibrates off you’ve got a really bad vibration). Take a video showing the tach and water as you slowly rev the engine. That will give you documentation of how severe and at what rpm it vibrates. It works really well.
If I understand your post, you ran the engine with only the balancer and flywheel, no clutch and it still vibrated. If so then that rules out everything external to the engine. I have chased a similar problem and determined the crankshaft flange was slightly undersized, so it didn’t center the flywheel correctly. The bolts don’t center it. A little bit of runout can cause a lot of vibration. I guess it’s not out of the realm of possibility that the flywheel could have shifted? Beyond that seems like it has to be internal to the engine. Maybe there was heavy metal added to the crank for balancing that came off? Somehow a connecting rod got bent, (hydrolock), crank bent for some odd reason?

Bob

[Gordon Levy]

message sent

[mburger]

If I understand your post, you ran the engine with only the balancer and flywheel, no clutch and it still vibrated. If so then that rules out everything external to the engine.

Bob

You are correct. The only thing external remaining are the injectors but I can’t think of what would create a vibration from injectors. I’ve verified proper fuel pressure set to 58 per my Pro-Flo requirements. (450hp max)
Thanks for the video idea!

[mburger]

message sent

Got it! Thank you!

[bobl]

You are correct. The only thing external remaining are the injectors but I can’t think of what would create a vibration from injectors. I’ve verified proper fuel pressure set to 58 per my Pro-Flo requirements. (450hp max)
Thanks for the video idea!

Uneven firing or misfiring could cause a vibration. But it seems to me if you can rev the engine past the vibration point and then let off and still pick up the vibration on decel that it would rule that out since there is no load.

[mburger]

Uneven firing or misfiring could cause a vibration. But it seems to me if you can rev the engine past the vibration point and then let off and still pick up the vibration on decel that it would rule that out since there is no load.

Vibration on decel. Great point. It does vibrate on decel.

[klawrence]

compression check all cylinders...may have bent a push rod. just a guess.

[klawrence]

what is your valve train ? hydraulic lifters, maybe one failed. Either way a compression check would be the next test to rule out the valvetrain.

[CraigS]

A friend had a problem w/ the surfaces on the crank that run against the thrust bearings not being machined properly. So the bearings wore very quickly which allowed the crank to move forward and back. It is usually fairly easy to pry the crank forward w/ a lever behind the crank pulley or just by pushing the clutch pedal down. You will need to get creative to figure a way to push it back. I don't know the exact spec but it is somewhere in the .007-.010 inch range so it doesn't move much.

[Jeff33Ford]

Have you verified spark to every cylinder? Also similar issues can occur if the cam timing is off in relation to the distributor. If your cam was set to 0 degrees, it may less likely to shift but can happen. This causes the distributor to be off as well. Have you put a timing light on it and see if the advance is correct during acceleration?

[mburger]

A friend had a problem w/ the surfaces on the crank that run against the thrust bearings not being machined properly. So the bearings wore very quickly which allowed the crank to move forward and back. It is usually fairly easy to pry the crank forward w/ a lever behind the crank pulley or just by pushing the clutch pedal down. You will need to get creative to figure a way to push it back. I don't know the exact spec but it is somewhere in the .007-.010 inch range so it doesn't move much.

Interesting. Would have been easier to check while we had the flywheel exposed!

[mburger]

Have you verified spark to every cylinder? Also similar issues can occur if the cam timing is off in relation to the distributor. If your cam was set to 0 degrees, it may less likely to shift but can happen. This causes the distributor to be off as well. Have you put a timing light on it and see if the advance is correct during acceleration?

Verified that when #1 is at TDC by the rocker arms, the distributor was pointing right at #1 as it should. We’ve only verified full advance at 3k. Also verified spark and I forgot I sent a pic of each plug to BP as requested.

[Fman]

I am sure you have already done this and run the diagnostics on the PF4 tablet, I had injector come off on my PF4 which was causing your symptoms (#6 cylinder). Popped connector back on and all was good. Have you also checked around your spark plugs to make sure your boots are not burned and possibly grounding out on the header?

[mburger]

I am sure you have already done this and run the diagnostics on the PF4 tablet, I had injector come off on my PF4 which was causing your symptoms (#6 cylinder). Popped connector back on and all was good. Have you also checked around your spark plugs to make sure your boots are not burned and possibly grounding out on the header?

Actually, I haven't run the diags. I forgot about it since splitting the engine/transmission is so much easier.
I did verify good burn at all cylinders with plug pics sent to BP.

I am going to make a video using a plastic cup of water on the air cleaner and the RPM displayed next to it on my tablet.
Also do a compression check.

[Gordon Levy]

Just for giggles check your firing order and make sure you don't have a couple wires crossed.

[Jeff33Ford]

Verified that when #1 is at TDC by the rocker arms, the distributor was pointing right at #1 as it should. We’ve only verified full advance at 3k. Also verified spark and I forgot I sent a pic of each plug to BP as requested.

Just to elaborate on what I was saying. If you verified #1 with the rockers then the distributor would be correct. If the cam has shifted in relation to the crank then the #1 piston would not be in TDC. It only takes a few degrees and it throws the timing of the dist off. A usual side effect is some popping with a sudden decel. But this can depend on which way the cam shifted.
Just another thing to check if all other options have been exhausted.

[ggunter]

According to Blueprint these engines are 28 oz externally balanced. I know you said you replaced your old balancer. Is your new one the 28 oz external balance? Just a thought. My 347 vibrated on decel when new and went away after a few hundred miles...Go figure.

[mburger]

According to Blueprint these engines are 28 oz externally balanced. I know you said you replaced your old balancer. Is your new one the 28 oz external balance? Just a thought. My 347 vibrated on decel when new and went away after a few hundred miles...Go figure.

Thanks for the input. It’s appreciated. Yes, this is an ACT externally balanced 28 ounce flywheel from Mike Forte. Ditto for my very expensive dampener But the dampener came from Summit.

Needed to clean up a few things on the car this morning but I am getting close to a video.

[Rickysnickers]

Hello mburger. I hope you still aren't having issues with your PF4.

[mburger]

Hello mburger. I hope you still aren't having issues with your PF4.

HAHA! Actually the PF4 is doing well! Just a little vibration issue.

[BluePrintEngines]

Hello Mark,

We are currently working with two techs on this matter. Ken and Johnny have been working very hard to get this issue resolved as soon as possible. I apologize we are experiencing this issue.

Thank You, BluePrint Engines

[mburger]

Thanks BluePrint.

Hey all.
It was suggested to me by someone who’s opinion I trust, that I remove the oil filter and cut it open. So that is what I will do. IF there is metal in the filter, we will stop and the long block goes back to BluePrint. Ken agreed with the plan.
If the filter is clear, we are going to install my original flywheel that was tested and balanced by BluePrint. According to BP, my flywheel was out of balance by 1.4oz. (40g) If it still vibrates, the long block will go back to BP. Ken is in agreement.
If the engine no longer vibrates, then we’re done, with no explanation of why it would take 6,000 miles for the vibration to appear.

[BradCraig]

I may be off-base and haven't fully read this thread, but I had an annoying vibration a few years ago on my '67 Camaro and it ended up being pinion angle. Something else to consider before you tear an engine out.

EDIT: Nevermind, I just saw you stated that it occurs in the driveway. :-)

[Sdonnel]

1.4 oz. may not seem like much, but remember the radius of the flywheel. That would be a major imbalance. Not sure why it took 6,000 miles other than maybe it was causing some early wear on bearing surfaces and they finally reached their limit. Hope you find it soon.

[BadAsp427]

Thanks BluePrint.

Hey all.
It was suggested to me by someone who’s opinion I trust, that I remove the oil filter and cut it open. So that is what I will do. IF there is metal in the filter, we will stop and the long block goes back to BluePrint. Ken agreed with the plan.
If the filter is clear, we are going to install my original flywheel that was tested and balanced by BluePrint. According to BP, my flywheel was out of balance by 1.4oz. (40g) If it still vibrates, the long block will go back to BP. Ken is in agreement.
If the engine no longer vibrates, then we’re done, with no explanation of why it would take 6,000 miles for the vibration to appear.

Sounds like you have a good plan in place. May need to get another mug and blow the foam off again while this all transpires...

[GoDadGo]

Good Luck!

We all hope you find the issue sooner than later.

[mburger]

Sounds like you have a good plan in place. May need to get another mug and blow the foam off again while this all transpires...

HAHAHA - Yes, I think I should!

[mburger]

Good Luck!

We all hope you find the issue sooner than later.

Thank you Steve! Very much appreciate it!

[mburger]

I removed the oil filter. I drained the oil from the filter through cheesecloth. The oil was very clean with no debris caught in the cheesecloth. I also examined the filter element and it too looked very good. No debris of any kind. The filter and oil looked so clean that I am not suspecting bearing damage but have not ruled out other damage within the long block. We will learn more once I receive my flywheel back and install it on the engine. That won’t be for a week but likely more.
Can’t tell you how much I appreciate all of your input and well wishes. You don’t find much of this on the Facebook groups. Blueprint thus far has been great as well.

[bobl]

Did they provide the flywheel or did you buy it elsewhere? They had to use a flywheel or flexplate to balance it originally.

[mburger]

Did they provide the flywheel or did you buy it elsewhere? They had to use a flywheel or flexplate to balance it originally.

I bought the long block through Mike Forte who supplied the flywheel. I purchased my Pro-Flo 4 through Mike as well. Mike installed everything and then put it on his dyno. BluePrint requested my flywheel back so QC could check it, and re-balance it if it was out more than 2g of 28oz. Apparently BluePrint’s flywheels are within 2g tolerance. They said mine was out 40g, balanced it to their specs and are sending it back to me.
Now, I have another ACT lighter weight flywheel on the engine now, and it still vibrates. So because of that, and the fact it didn’t vibrate for 6k miles, I’m not confident my original flywheel will fix it.
I sure as heck don’t have any answers but I’m in the hole about $1,000 troubleshooting this.
I bought my long block from BluePrint because of their warranty and customer service, hoping I’d never need it, so I’m confident they’ll figure it out.

[SJDave]

I had a vibration problem on mine also that was a bugger to troubleshoot. Wasted a lot of time and money trying to solve it, then I decided per the suggestion of someone on the forum to have the flywheel checked again for balance and the pressure plate assembly. Flywheel was perfect, Pressure Plate assembly was out 15 grams which was fixed by welding on some steel to the OD of the housing. Problem solved. This wasn't a high end racing clutch or anything, just a king Cobra clutch made by Valeo, my luck sucks!

[Nigel Allen]

G'day Mark,

SJDave's comments got me thinking, could something have gone wrong with the clutch assembly? Caveat - I make a better sparky than a mechanic. Also the clutch on my car was the only item that I did not have anything to do with.

Because the vibration has evolved over time, my thoughts went this way; is it possible for for the wearing components of the clutch to wear / fail in such a way as to go out of balance?

Best of luck getting to the bottom of it. I can certainly understand the frustration.

Kind regards

Nigel