Is there a difference between the flywheel for a 304 and a 345 with a manual transmission? I had a 304 in my Scout now im switching to a 345 and went to bolt it up and realised it will not fit.. I just went and had the flywheel machined and the clutch rebuilt. Is the clutch going to work with the 345 flywheel?
345 and 304 manual transmission differences??
- Thread starter tnhotrod
- Start date
Robert Kenney
Super Moderator
If the clutch bolts up ok to the 345 fw you should be good to go.
Is the 345 flywheel native to the 345? It could very well be balanced to that particular rotating assembly. Put a differant flywheel on the 345 and you could end up with a vibrating pos. But if you are the gambling type go for it.
while the 304 flywheel will bolt up it May not be very well balanced to the 345. I would bet it is aways off.
It appears that you probably have a flywheel from an "older" 304 -- late 60's ???
Is there a part number stamped on the flywheels?
The parts book (72 - 73 t/a + p/u) that I have shows nnnnnnr21 -- which means there are 20 "versions" before "this flywheel"...
From what I have read, flywheels are drilled / tapped to accept different size pressure plates ("clutches") (10 in, 11 in, 12 in). Some flywheels are drilled / tapped for two different size pressure plates.
Obviously, if you have a flywheel that is only drilled for a 10 in pressure plate; the others (11in / 12in) will not bolt up.
I think the 12 in clutches were used in loadstars / med duty trucks (my 1210 t/a came with a 11 in clutch).
As robertk states, there could be "balance issues" if you swap flywheels (or harmonic balancers) as IH engines were externally balanced at the factory.
But, I think this is actually an engine that you are rebuilding(?).
Is there a part number stamped on the flywheels?
The parts book (72 - 73 t/a + p/u) that I have shows nnnnnnr21 -- which means there are 20 "versions" before "this flywheel"...
From what I have read, flywheels are drilled / tapped to accept different size pressure plates ("clutches") (10 in, 11 in, 12 in). Some flywheels are drilled / tapped for two different size pressure plates.
Obviously, if you have a flywheel that is only drilled for a 10 in pressure plate; the others (11in / 12in) will not bolt up.
I think the 12 in clutches were used in loadstars / med duty trucks (my 1210 t/a came with a 11 in clutch).
As robertk states, there could be "balance issues" if you swap flywheels (or harmonic balancers) as IH engines were externally balanced at the factory.
But, I think this is actually an engine that you are rebuilding(?).
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
All the info that has been posted here is golden.
You will have a major balance issue. Unless...ya have the flywheel/clutch disc/pressure plate/mounting bolts that will be used on this engine neutral balanced by a knowledgeable machine shop.
The flywheel part numbers reflect a difference in the drilling patterns for which clutches were used in which oem truck application, just as Robert described. Otherwise the flywheels are dimensionally the same regarding the counterweight position. Each flywheel was matched to each engine at the point of engine assembly.
However...a replacement flywheel obtained through ihc as a service part would have been neutral balanced, that is why a "service part" May be used on any engine app as long as the clutch drillings are proper.
Since this engine is in the rebuild state, why not have the entire rotating assembly balanced, now is the time!
Additional info regarding this subject is here:
http://www.forums.IHPartsAmerica.com/transmission-tech/1017-proper-clutch-identification.html
You will have a major balance issue. Unless...ya have the flywheel/clutch disc/pressure plate/mounting bolts that will be used on this engine neutral balanced by a knowledgeable machine shop.
The flywheel part numbers reflect a difference in the drilling patterns for which clutches were used in which oem truck application, just as Robert described. Otherwise the flywheels are dimensionally the same regarding the counterweight position. Each flywheel was matched to each engine at the point of engine assembly.
However...a replacement flywheel obtained through ihc as a service part would have been neutral balanced, that is why a "service part" May be used on any engine app as long as the clutch drillings are proper.
Since this engine is in the rebuild state, why not have the entire rotating assembly balanced, now is the time!
Additional info regarding this subject is here:
http://www.forums.IHPartsAmerica.com/transmission-tech/1017-proper-clutch-identification.html
I used a 266 flywheel on a 345. The 266 was a 1968 and the 345 was a 1976. Bolted right up. I didn't notice any vibrations in the 10 years that I drove that Scout.
Not saying that it couldn't happen but imo the balance problems are overblown. Especially on an engine that wont rev to 4k.
The Scout flywheel should have an adapter that presses into the center of the flywheel to hold the pilot bearing.
The larger trucks didn't use the adapter. The pilot bearing pressed directly into the center of the flywheel.
Can you post pics of what you have?
Not saying that it couldn't happen but imo the balance problems are overblown. Especially on an engine that wont rev to 4k.
The Scout flywheel should have an adapter that presses into the center of the flywheel to hold the pilot bearing.
The larger trucks didn't use the adapter. The pilot bearing pressed directly into the center of the flywheel.
Can you post pics of what you have?
Robert Kenney
Super Moderator
We do not practice back yard bs here. Engine balancing is one of the most critical steps in building any engine. Neither michael nor I will recommend any course of action that May end in a poorly balanced situation.
We don't play around when risk of another's property is at hand.
Where in engine dynamics ethics is it written that 4000 rpm is below the harmonic do so. Threshold ????? The fact of the matter is, an improperly balanced engine can/will exhibit vibration at idle and gets exponentially worse with rpm. Of course the amount of the non balanced moment will ultimatly determine how bad the vibration is. Why risk it.
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Dont attack me! I'm just stating what I believe as well as my experiances with engines over the years.
Every engine when new was balanced at the factory be it a Chevy, Ford, ihc etc.
Every year many engines get replaced. Some with a complete engine from a junkyard and others get long or short blocks from various rebuilders.
Flywheels and flexplates get replaced, balancers too.
The long and short blocks do not usually come with harmonic balancers or flexplates/flywheels. The standard practice is to re-use the old ones from the original engine.
I wonder how many rebuilt engines are balanced? I bet very few except for some hi-po engines the rebuilders sell.
Michael Mayben
IHPA Tech Moderator - Retired & No Longer Online
Chris, we don't care what "might" be in some historic viewpoint regarding any other engine product.
In this forum, we deal in fact and information that can be supported by data.
And...one of our many, highly experienced vendors who work with ihon directly, was involved in all aspects regarding IH-produced engine products as a longterm field engineer in the warranty department. He served time on the engine assembly line actually performing engine balance operations. It is he who trained us in how this was done as regards IH engine products and is still done in a very similar fashion today.
We don't give a shit about chryfordrolet motors or what any other engine rebuilder "might" do. And any responsible engine builder who is going to replace a rotating component is gonna make dam sure it's neutral balanced if they install the part and stand behind their work.
And because boneyard shit happens, doesn't make it "correct".
Maybe you don't understand what this forum is about? This is not a place to toss out bs like some other "boards". We deal in fact here, stuff that we have to stand behind when dealing with our vendors and our customers. If we supply a "used" component to a customer, it is with the understanding that they are making the buying decision, if "balance" is an issue with replacing clutches, flywheels, flex plates, crank hubs, harmonic balancers, etc., the customer bears the responsibility of dealing with the consequences if the decision he/she made doesn't work out.
In this forum, we deal in fact and information that can be supported by data.
And...one of our many, highly experienced vendors who work with ihon directly, was involved in all aspects regarding IH-produced engine products as a longterm field engineer in the warranty department. He served time on the engine assembly line actually performing engine balance operations. It is he who trained us in how this was done as regards IH engine products and is still done in a very similar fashion today.
We don't give a shit about chryfordrolet motors or what any other engine rebuilder "might" do. And any responsible engine builder who is going to replace a rotating component is gonna make dam sure it's neutral balanced if they install the part and stand behind their work.
And because boneyard shit happens, doesn't make it "correct".
Maybe you don't understand what this forum is about? This is not a place to toss out bs like some other "boards". We deal in fact here, stuff that we have to stand behind when dealing with our vendors and our customers. If we supply a "used" component to a customer, it is with the understanding that they are making the buying decision, if "balance" is an issue with replacing clutches, flywheels, flex plates, crank hubs, harmonic balancers, etc., the customer bears the responsibility of dealing with the consequences if the decision he/she made doesn't work out.
The fact of the matter is that you can get new and or rebuilt balancers that are bad. Case in point the 404 john deere engine, I've replaced several balences on that series engine where either the outer ring completely came off or it slipped a few degrees. Just because you buy new doesn't mean that you necesiarally have something "good" and the same can go for clutch discs and pressure plates. And I doubt that many ever send a rotating assembly for a stock application out to be balanced when the clutch and pressure plate are replaced.
Should your rotating assembly be checked for balance, yes. Especially in a short stroked, high revving engine. Can you get by at your own risk not doing so, yes if that is your choice. It really depends on the use of the engine and the desires of the person that owns the engine. It is also the responsibility of the builder to explain the risks associated with their choices.
People get buy with replacing crankshafts all the time without doing a line bore of the block, I personally think that they are insane for doing so. But it doesn't change that fact that some do not wish to spend the extra cash if they think that their particular application can operate to their requirements without doing so.
This is sort of off topic --
thehud --
to have your deere harmonic balancer rebuilt, you might want to check out dale mfg (salem, or - www.dalesmfg.com).
He started out doing corvair harmonic balancers in the 70's.
It does not look like he has done a deere (does show allis chalmers / case) -- he lists the harmonic balancers he has rebuilt on his web site.
thehud --
to have your deere harmonic balancer rebuilt, you might want to check out dale mfg (salem, or - www.dalesmfg.com).
He started out doing corvair harmonic balancers in the 70's.
It does not look like he has done a deere (does show allis chalmers / case) -- he lists the harmonic balancers he has rebuilt on his web site.
Thanks for the heads up. I generally put on new balancers if I can, and the common one on the 404 isn't too hard to come by. Some of the odd ball ones on power plant engines are a little more difficult though.
I've got a rebuilt 304 out of a 1970 truck with an automatic, that I am putting into a 69 truck with a manual transmission. When I went to switch the flywheel, I found that the bore on the flywheel from the 69 is 2" dia whereas the crank pilot is 2 1/4" dia. The bolt pattern matches; can I just bore the flywheel to match the pilot and put it on as long as I match the pin location?
Scoutboy74
Moderator
Welcome to the forum. The starter ring gear for auto transmissions is called a flex plate. What you should do is swap the crank hub spacer from the dead engine over to the donor engine. That will then allow you to install the proper manual trans flywheel from the dead engine onto the donor engine. Machining the auto flexplate in the manner you've proposed is a no go. This type of retrofit has been done numerous times by numerous folks over the years for engine swap and transmission swap scenarios. Usually there are no issues as a result. External balance is an important consideration with the IH sv8 engines. There is a small possibility that the flywheel from the dead engine May be just enough out of balance with the donor engine to cause vibration issues at a certain rpm range.
Scoutboy74
Moderator
No adapter involved here. The part we're discussing is a cast iron object, circular in shape that is fastened to the crankshaft with a series of hardened steel bolts and a locating pin for the ring gear. They are not all the same. The thickness of this piece as well as the shaping of the ring gear mating surface is integral to the ring gear design and transmission type that is being utilized. Just look at the two pieces side by side and you will see that they are vastly different. Your success here boils down to a simple matching of correct part a to correct part b to correct part c. The borg warner auto trans that IH offered as optional equipment during the mid 60's into mid-'72 has one style of starter ring gear and hub spacer...then when they switched to the chrysler tf a727 in mid-'72 through end of production, those units required a different flex plate and hub spacer. And of course the standard trans configurations have their unique flywheel and hub spacer. The parts are generally interchangeable as cohesive sets, but shouldn't be partially mixed and matched. Keep all standard trans engine mating stuff segregated from the auto trans mating stuff in other words.
Scoutboy74
Moderator
You're welcome.