[TVR383]

I need to replace my flywheel and clutch assembly while my engine is out might as well do it now.

This motor was rebuilt and balanced last fall...have to open it again as it burns oil. Checking the work report done to it I see it was balanced externally in the front and internally ,in the rear...I am not sure but having an 8 inches 400 damper on the front is balancing then achieved through drilling into the damper to take weight of?
According the work report the rear part of crank had some heavy metal put into it to have this area of the motor balanced..does that mean the flywheel and clutch assembly were not touched to achieve balancing?

In such a situation can I buy a flywheel and clutch ****embly advertised as "neutral" as far weight distribution is concerned and just bolt them on and not to have to worry about rebalancing the whole rotating again?

Another question do I need to look for a 400 flywheel or a 350 one? Actually I have a hayes flywheel (not sure wich model) and a dual friction centerforce clutch and would like to replace them with the same.

thanks,Ronald.

[xntrik]

Originally Posted by TVR383

I need to replace my flywheel and clutch assembly while my engine is out might as well do it now.

This motor was rebuilt and balanced last fall...have to open it again as it burns oil. Checking the work report done to it I see it was balanced externally in the front and internally ,in the rear...I am not sure but having an 8 inches 400 damper on the front is balancing then achieved through drilling into the damper to take weight of?
According the work report the rear part of crank had some heavy metal put into it to have this area of the motor balanced..does that mean the flywheel and clutch assembly were not touched to achieve balancing?

In such a situation can I buy a flywheel and clutch ****embly advertised as "neutral" as far weight distribution is concerned and just bolt them on and not to have to worry about rebalancing the whole rotating again?

Another question do I need to look for a 400 flywheel or a 350 one? Actually I have a hayes flywheel (not sure wich model) and a dual friction centerforce clutch and would like to replace them with the same.

thanks,Ronald.

Burning oil -- Sounds like you have a fairly serious machine shop problem.

A good machine shop will NOT modify a dampner nor a flywheel (nor clutch) to balance an engine. Either part should be a standard "off the shelf" part. By what you said, a zero balance 350 flywheel is what you need.

Note: with a "cross balanced" crankshaft a stock dampner will NOT adequately dampen harmonics of the crankshaft. An aftermarket unit is mandatory.

check out www.readershotrods.com drag cars/georges drag strip

[techinspector1]

All you needed in the first place was a 400 damper and a 454 flywheel. What's with all this Mallory metal??

[TVR383]

Originally Posted by techinspector1

All you needed in the first place was a 400 damper and a 454 flywheel. What's with all this Mallory metal??

454 flywheel?! The flywheel actually on the 383 is a Hayes 10-130 wich is for:1955-1985 chevys V-8 except 400s and 454s...I bought that car with this into it so I don't know why its been choosen among other hayes flywheels! But it was certainly working allright!

The work order report done on this engine last fall says: ballanced external in the front (400 damper) ,internal at the rear with two malory (neutral flywheel).

Hayes web site refers to that flywheel as a neutral without counterweights onto it..I kind of remember the machinist telling me that the GM 400 crankshaft while allowing the use of malory at the rear didn't offer any possibility to do the same at the front..

SO what I understand is the flywheel can be changed without worrying about reballancing but I am not sure about the clutch itself..isn't a clutch assembly in need of being taken in account when ballancing?

confused somewhat here!!

thanks,Ronald.

[machine shop tom]

When we balance an externally balanced engine, we first measure and correct (if needed) the imbalance in the balancer and flexplate/flywheel (Some can be WAY off). That way if these pieces need replacement, the new pieces can be measured and made like the originals.

Balancing the back neutrally while leaving the front externally balanced doesn't make much sense to me. They'd have some 'splaining to do if it were mine..........But the fact that they did something like that may help explain why it burns oil.

tom

[TVR383]

Originally Posted by machine shop tom

When we balance an externally balanced engine, we first measure and correct (if needed) the imbalance in the balancer and flexplate/flywheel (Some can be WAY off). That way if these pieces need replacement, the new pieces can be measured and made like the originals.

Balancing the back neutrally while leaving the front externally balanced doesn't make much sense to me. They'd have some 'splaining to do if it were mine..........But the fact that they did something like that may help explain why it burns oil.

tom

Tom,

Thanks for your explanations...Yes from my invoicing I can say this is the way the motor got ballanced..external/front and internal/rear..

Could you explain ,what in your opinion,can finally get an engine consuming oil when balanced in such an odd way?

Ronald.

[baddbob]

That engine can be balanced that way with no problems, I don't however know why they modified the balancer which should have stayed at the stock imbalance for replacement reasons. A nuetral balanced flywheel makes it easy to replace when necessary which is a great plus, especially if you ever decide to switch over to an automatic for example. Most shops don't bother with balancing the pressure plates as they are supposed to be nuetral balanced from the manufacturer, the clutch disc is never balanced so as an assembly it really is never perfect. Another option rather than using heavy metal is to use a balance plate that gets bolted on with the flywheel and can be used again and again to keep the assembly balanced when flywheels/flexplates are changed. It sounds to me that maybe your balancer wasn't the right imbalance so maybe the shop tuned it in to where it should be. Talk to them. The balance shouldn't really effect ring and valve stem seal IMO so I'd lok for other causes for the oil consumption, bad ring seal, bad valve guide seal, leaking intake gasket, poor crankcase ventilation setup, etc...

[TVR383]

Originally Posted by baddbob

That engine can be balanced that way with no problems, I don't however know why they modified the balancer which should have stayed at the stock imbalance for replacement reasons. A nuetral balanced flywheel makes it easy to replace when necessary which is a great plus, especially if you ever decide to switch over to an automatic for example. Most shops don't bother with balancing the pressure plates as they are supposed to be nuetral balanced from the manufacturer, the clutch disc is never balanced so as an assembly it really is never perfect. Another option rather than using heavy metal is to use a balance plate that gets bolted on with the flywheel and can be used again and again to keep the assembly balanced when flywheels/flexplates are changed. It sounds to me that maybe your balancer wasn't the right imbalance so maybe the shop tuned it in to where it should be. Talk to them. The balance shouldn't really effect ring and valve stem seal IMO so I'd lok for other causes for the oil consumption, bad ring seal, bad valve guide seal, leaking intake gasket, poor crankcase ventilation setup, etc...

I just want to clarify about the 400 damper: about drilling into it to achieve balancing was a question of mine in my first post as could this method considered as a good one...as I don't understand how else modifying weight distribution onto the damper could be achieved! I don't know if my builder actually used this method or not.


thanks for your help,
Ronald.

[machine shop tom]

I was thinking that unless they had a good reason to add the heavy metal to the back of the crank (perhaps you just had to use that particular flywheel?), they had less than practical reasons to do so. In that case, perhaps they have strange methods of bore finishing that may explain the oil burning. I didn't mean to imply that balance can influence oil burning---it can't.

tom

[techinspector1]

454's are externally balanced, so if you want a stick-shift 383, you use a 400 damper and a 454 flywheel. If you ever want to revert to an auto trans, just replace the 454 flywheel with a 400 flexplate. Problem solved.

[TVR383]

Originally Posted by techinspector1

454's are externally balanced, so if you want a stick-shift 383, you use a 400 damper and a 454 flywheel. If you ever want to revert to an auto trans, just replace the 454 flywheel with a 400 flexplate. Problem solved.

After digging for more informations on that subject I came to understand that a 400/454 flywheels are externally balanced through weights hooked onto their edges...Is this right? And the 350s flywheels don't have such counterweights cause they are meant to be coupled to engines balanced internally and these peculiar flywheels are neutral in their weight distribution...? Am I right?

I bought that car with already in it that 10-130 hayes flywheel initially meant for plain 350s(now I understand this)...this case obliged for internal balancing through mallory into the crank..another possibility would have been drilling holes onto the flywheel and attach counterweights onto it..my understanding anyway. But for one reason or another my machinist decided to go by mallory into the crank.

The following is adressed to Machine Tom: The reason (from what I can remember)given to me by the engine rebuilder for having not internally balanced in the front is that the crank being a GM cast number 529 crank didn't allow the use of mallory onto the front counterweights (or similar) as he could (and did) do in the rear counterweight (s)...makes sense to you? He told me that with an eagle or other aftermarket he could have done it all internally but not with my crank...he sounded like knowing what he was talking about. But I can understand and accept the fact of different opinions and ideas on a same subject.

just as a PS I have the hynes balancing report on hands and cannot figure it out..at least some part of it! If I'd give the numbers here somebody could explain me the missing links?
thanks,Ronald.

[machine shop tom]

I suspected that was the deal with the flyhweel. Personally, I'd have suggested that you get the proper flywheel and balanced the crank normally. The cost difference would have offset somewhat by not needing the heavy metal installation.

You are correct about the flexplate weights.

I use a Hines balancer and can probably answer your questions about the balance documents.

tom

[machine shop tom]

Originally Posted by techinspector1

All you needed in the first place was a 400 damper and a 454 flywheel. What's with all this Mallory metal??

The imbalance is not the same in the 400 and 454 flexplates.

The 400 has a 25.1 OZ/IN imbalance.

The 454 has a 33.64 OZ/IN imbalance.

Enough difference to cause problems.

tom

[techinspector1]

Originally Posted by machine shop tom

The imbalance is not the same in the 400 and 454 flexplates.

The 400 has a 25.1 OZ/IN imbalance.

The 454 has a 33.64 OZ/IN imbalance.

Enough difference to cause problems.

tom

thanks for the head-up Tom. I was just talking to my buddy in Missouri who did one of these stick-shift 383's and he mentioned nothing about the imbalance adjustment. I'll have to get back to him and inquire about the procedure he used to address this issue. Have you done this before and if so, how much material did you have to remove from the 454 'wheel to make her spin smoothly? I would assume you would want the weight the same as the 400, but what size drill and how deep?

[TVR383]

Originally Posted by machine shop tom

I suspected that was the deal with the flyhweel. Personally, I'd have suggested that you get the proper flywheel and balanced the crank normally. The cost difference would have offset somewhat by not needing the heavy metal installation.

You are correct about the flexplate weights.

I use a Hines balancer and can probably answer your questions about the balance documents.

tom

Tom,

I'll take advantage of your knowledge for sure..thanks.
What I have on the balancing specs sheet are the followings: piston:483,piston pin:129,piston rings:49,pin locks:4,total rod:567,insert:45,rotary:445,reciprocating:1664 (nothing indicated as the % factor found on the same line),bob weight:1726.

I assume the total of all those,up to the two last figures,represent the total minimum weight of each one piston/rings/rods etc,...all other 7 similar having been adjusted to the said minimum!?


while "piston,rings,pin,etc are easily identified I don't know what "rotary" refers to!?

When adding each individuals weights we get a total of 1722...close to the 1726 indicated as bob weight...can I think of bob weight as the mallory used to counterweigh the 1722..that would be a balanced to 4 gramms ? If so that sounds far from the 1/2 gramms precision we are referred to as the excellent balancing figure..

Wouldn't normally each throw having had received such counterweight as in my mind each of the 7 pistons and parts weigh the same 1722...I my report indicate two malory only installed at the rear..

Finally the 1664 gramms as the "reciprocating " number...what does it represent?

can you thrown in some explanations?

thanks,
Ronald.