engine vibration
 

i recently installed a new chevy big block in my boat. i used the old balancer and fly wheel off the old chevy big block, the new engine has a bad vibration even when its at idle and not in gear. could the outdrive be out of alignment and cause this or do i need to start with the balancer and fly wheel. thanks

it sounds like you might have the wrong balancer and or flywheel ,can you give more info like what year the boat is and what year the replacement engine is?

I would think the balancer and flywheel need to be balanced together to the motor. Had to pull one of my 302's in a welcraft Nova once because the damn engine builder didn't balance one of the motors... I was not a happy camper.

fixx
 

all he said was he replaced his BB,like mike said we need more info on the old and new engine,,did he replace it with a 454 or 540 stroker? lol..

If it was not a 454 balancer and flywheel and from the same Gen 454 for a 454 then like said you got the wrong stuff.

The balancer and flywheel need to be balanced with the engine rotating assembly.

as like everyone said you need to know what gen 4,5,6 internal or external balanced?

I just love a good dyno.

If your old motor was a stock 454 and the replacement the same ,the stock balancer and flywheel should be fine ,,,without balancing to replacement motor . Sounds like you have a neutral balance flywheel on an external balance motor ..or vice versa.................Like everyone else asked ...what did you replace with what ...other than just a bbc

thanks for the reply's , i am waiting for a call back from the engine builder and will let everyone know

the old motor was stock, the new one has almost double the HP,

Make sure you do not have a couple plug wires mixed up, out of the 1-8-4-3-6-5-7-2 firing order. Was the cam a 4-7 swap?

Just for my future ref… If you have two same gen Chevy BB motors. The balance on the flywheel and the balancer are exactly the same? And interchangeable (always) I know it wasn’t that way on a couple older Mercruiser 302’s but I do mean older (73) 888's...

Yes that's what i'm saying . Gen for gen ,and displacement..If you were to buy a reman without a balancer and flywheel, you use your old one,right .In a hi hp situation it is obviously better to have the entire rotating assemble balanced. But if that was the case in this thread the engine builder should have asked for the op's flywheel and balancer...Wonder if the builder in this situation just put on some different pistons without worrying about balance ...Or builder bought an internal balanced assembly and op put on his external balanced flywheel and balancer. curious

If the engine came from the engine builder with no balancer or flywheel then its more then likely internally balanced. Especially if your saying its a high hp engine. If it is external then the engine should have been balanced with the flywheel and balancer. I have seen also some shops work on the flywheels to get a crankshaft balanced and that's the wrong thing to do because if you ever have to replace the flywheel the crank will be out of balance.

ok, i went down and pulled the balancer off the motor and its an externaly balanced, i talked to the engine builder last week and he said the engine is externaly balanced and any BB externaly balanced flywheel and balancer will work, my best bet would be to just go to his shop and look at the one's he used to balance my motor. dont know what else to do.

here is the engine that is in the boat www.ebay.com/itm/230951113710

i believe your builder is mistaken,the counterweight on a mark 4 is different than a gen 5 or6.

fixx
 

+1 and from what that pic looks like it has a 396/427 ballancer on it if that is the exact same engine..it should only have that ballancer on it if it has a forged crankshaft and internally ballanced.

this has always confused me as most balancer manufacturers show the same balancer for MK4 and Gen5 and some also fitting Gen6 (although I think that is if you dont have the trigger wheel on the crank) I have a balancer that is off a Gen5 and it is the same balance and my mk4 with the only difference that I could find was the counterbore for the pulley was not on the Gen5 one. I know the flywheel IS different due to the loss of the cast on counter weight on the rear crank flange but it seems the balancer is shown as the same and that would make sense. this is for my 454 so the 502 may be balanced different.

and according to the ad it is externally balanced.

7. THE CRANKSHAFT IS BRAND NEW AIRCRAFT QUALITY PRO-COMP CAST STEEL 4.250 2 PIECE REAL SEAL CRANKSHAFT.THE CRANKSHAFT IS SHOT PEENED FOR STRESS RELIEVING AND HAS A FULL .125 RADIUS ON THE MAINS AND ROD JOURNALS!, THIS CRANKSHAFT IS ALSO EXTERNALLY BALANCED AND IS THE BEST OF THE BEST!!(4.250 STROKE, 1/4 INCH LONGER THEN STOCK 454), FRESHLY MICRO POLISHED AND STANDARD ON THE ROD AND MAIN JOURNALS.

8. THIS ENGINE IS FULLY BALANCED ON OUR NEW RMC COMPUTER BALANCER AND IT IS ALSO BLUEPRINTED. PISTONS, RODS AND CRANKSHAFT ARE BALANCED TO LESS THEN 1 GRAM. ( MOST MACHINE SHOPS ONLY BALANCE TO A 5 GRAM SPREAD) BEARING CLEARANCES WERE SET AT .002 ON BOTH THE MAINS AND RODS.

So what do you think would be the correct one's to put on this engine.

at this point i would suggest that you take the complete rotating assembly along with your flywheel&balancer to a competent machine shop and have the balance checked out,it is obvious that you have a problem and cannot run the engine as it is.

I would have to agree. their ad says it is externally balanced to less than a gram but if it did not come with a flywheel and balancer then you dont know what they used when they balanced it.

Ok, sorry to be blunt...what you bought is junk ! sorry 1st nobody balances a stroker assembly with out the specific balancer and flywheel ! most all stroker cranks I've seen use a non-counter weighted balancer/flywheel..aka scat/eagle...next those pro-comp heads are about as junk as they get..sorry again...but selling for that $$$ what did you expect ? thats about the cost of a good pair of aluminum heads...now what you might do is ck the crank and see if in fact they say interally balanced...you may swap in a 427 balancer/flywheel and get it smoothed out...

I hate to tell you this, but a buddy of mine bought a 496 from these guys last year to put in his 63 Impala. Long story short, he had to take it to a local machine shop and spend another $6k to make it right. Most of the internal parts were junk and unuseable. Engine would not even start when initially installed. Funny thing, I tried to discourage him from buying it in the first place.

I have read some reviews on this shop and there about 50/50, i didnt have much imput when this, when the engine was purchased but its what i got. it runs good, its just the vibration, i emailed a few other people that have bought these engines this morning and one of them said he is running an external balanced 454 fluid balancer and a flex plate off a 427 and took them down and had them balanced togrther and he said its running great.

Are you sure the flywheel is mounted correctly. If the dowel pin has been removed from the crank and you do not line it up correctly you will get one hell of a vibration even at idle.
I learned this he hard way when I was younger.:eek:

I did the exact same thing! The dowel pin had been removed just like you stated. Started it up and it was terrible! The counter weight was 180 degrees out! Won't take you long to figure out something is terribly wrong!

If your friends is externally balanced ,running a 427 flex plate makes no sense.427 flywheel is neutral balance .

I agree...no way a 454 balancer and a 427 flywheel should work...something is WRONG with that deal as well...I bet you serious $$$ the balance WAY off and questionable if can get balance correct...I work with a great engine builder and we talk all the time...I had to redo a factory GM 454 last year that I bought brand new...had a vibration(not bad) about 1800...was in my gibson..ran it for 2 seasons 125hrs...spun a rod bearing..now this engine spent it's entire life @3200 never saw 4000...pulled apart had a scat crank in a new GM engine..bought another one they sell as a factory balance one for GM....my guy said he was barely able to get balance right..with balancing !! so if yours vibrates like that pull it out...take to a good engine shop now...as it will not stay together...at least you will know what you have there...now..all we know is that the pin has been removed !!
if you search on here about procomp heads you get a earfull on what other have found...so I can only imagine what the cranks/rods are like...

Not trying to bum you ,but because of the problems you are having ,,,have you attempted to just get your money back..
In the link that was provided that motor sold for 2600 and change ...Is that what you paid ?Good set of heads cost more than that .....
TRY to get your money back .....JMO
FWIW I had seen those motors before at something more than 2600 and was curious as to the quality of machine work .I already know the lack of quality of parts...Sorry chief

This would be the first and easiest thing to check.

Im planning on pulling the engine in a couple of weeks to see what flex plate is on it. a few people are telling me to run a fluid balancer on it. and if so what flex plate do you use. external or zero balanced?

No fluid balancers in a boat. After the boat sits (in some cases months at a time) the fluid settles in the bottom of the balancer and when started it will snap the crank nose off.

First of all, do you have data or facts to back your statement that if using a Fluidbalancer, the fluid settles in the bottom and at start up snaps the crank off? I have been doing this for 23 yrs have used Fluidbalancers from Fluidamper, and have NEVER, had an engine vibrate or break a crank after sitting or cause bearing damage due to harmonics from the balancer.
Now on the build; if typically building a 4.250 stroke engine, the engine should be balanced internally, needless to say; I have seen engine over 4" stoke balanced externally. If the rotating assy was balanced either internally or externally, the balancer and flywheel should be verified either to be neutral or counter-balanced. I have seen externally weighted flywheels drilled on that will change your balance, if the same flywheel or balancer is not used during balancing, same goes for a neutral engine. Some times people are Lazy, and they drill the flywheel, when it should be neutral. Have someone verify the flywheel is neutral.
They could have made a mistake adding or measuring the bob-weight, totals. This is usually noted by experienced professionals, knowing the average weights used with the pistons and rod combinations used in the past. BBC around 2300-2400 grams total, then divide that in half for each half of your bob-weight.
Hope this helps, Mark

No personal experience but that's what I was told by the folks I bought a crank from (no names, not throwing them under the bus). Also read about it on line. Could be nothing but why take the chance? It's kind of believable. Maybe you buy better ones and it's just the cheaper ones. I don't know.
But I cant see why you would want one if you are balancing a motor anyway.

they do not use flex plates, std trans flywheels, the external or not flywheel/balancer determined by the crank...most std 454 use a external counter weight....but they are a few differences gen IV vs VI as well as some aftermarket cranks...most stroker cranks use a zero weighted one...

well I brought the boat home from havasu to pull the motor and I did that today. it has an external balanced flywheel and balancer on it just like the engine builder said to use. do I throw all neutral balanced on it and see what it does or do I tear it down and have it balanced again.

"THE CAMSHAFT IS A NEW ELGIN INDUSTRIES E1143P AND WITH A TRUE CLOYES DOUBLE ROLLER CHAIN SET. THIS CAMSHAFT IS A HYDRAULIC LIFTER GRIND .576 LIFT 246 DURATION @.050 ON BOTH THE INTAKE AND EXHAUST AND IT IS GROUND ON 108 DEGREE LOBE SEPERATION. THIS CAMSHAFT HAS A DISTINCT LOPY IDLE AND IS DESIGNED TO MAKE MAXIMUM POWER IN THE 2500-6500 RPM RANGE"

I'm no marine eng expert, but if you're going to tear this eng down, might wanna consider replacing the cam. This one doesn't sound boat friendly.
Maybe one of the more experienced guys can weigh-in on this.