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Discussion Starter #1
My truck has been running kinda off lately. When starting it after it's been running it makes funny noises like the starting can't engage good. I took it to my buddy's shop because it is having a fuel issue as well now(bogging out when you step on it) and he is willing to do my work at cost because he's a good friend. He called me and told me the flywheel is all tore up and it'd be like $630 for that and a new starter. I told him I'd pick it up Friday and take a weekend off work to replace it myself. What I'm worried about is what could CAUSE this to happen? :doh0715:

~Keith
 

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If it actually is a flywheel, and not a flex plate (manual trans has a flywheel, auto has a flex plate) then you can replace the ring gear that the starter engages. Heat the ring gear with a torch and pry it off, it is just a press fit. Buy a new one at autozone for like $25 and put it in the oven for an hour, take it out, drop it on and let it cool, and presto, it's fixed. Buy a new starter for $50 and you are done.

You can buy a complete replacement flywheel for less than $100 at the big box auto parts stores. If it is an auto, w/ a flex plate, they can be had for under $30.

It happens normally because either: The engine backfires a lot while cranking and strips teeth. The starter began to go bad and the bendix did not fully engage and you kept trying to start it like that. The starter engaged and never disengaged once while you had the engine running. The starter needed shims to be in proper gear mesh and they were never properly installed. Or the starter bolts got loose and the starter misaligned and had bad gear mesh. It can happen due to normal wear, but if the gears are properly meshed and everything is working right it should take ages for the two gears to wear badly.

Good luck,
Jason
 

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that was a really good explanation, i learned something tonite. thanks jason.

sorry to hear about your bad luck tho dvl.
 

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If it actually is a flywheel, and not a flex plate (manual trans has a flywheel, auto has a flex plate) then you can replace the ring gear that the starter engages. Heat the ring gear with a torch and pry it off, it is just a press fit. Buy a new one at autozone for like $25 and put it in the oven for an hour, take it out, drop it on and let it cool, and presto, it's fixed. Buy a new starter for $50 and you are done.
As a fabricator who has done that sort of thing (heat something up or cool something down) to make it fit in place with out welding (and sometimes welding as well) I can assure you that if you have never done this before then I don't suggest doing this. Because you have one shot at doing this. If you don't have spacers set up to make it all line up just right than you are just wasting your time and money. Even though I have heated things to make them fit successfully, in this instance, i would just buy a whole new flywheel.


Keith, I think you should buy a whole new flywheel and I think your starter solenoid is going on you. Or perhaps you are a girl and tried to start your truck when it was already running...beeeooch:goodfinge
 

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Bullshit. I have changed several ring gears this way. The flywheel has a lip machined, the ring gear has to sit tight on the lip. There are no shims to go in place. You heat it up and wack it down until it is seated in place. Machinists do this all of the time to get a semi-permanent fit with chucks and arbors. You can install a drill chuck arbor this way and it will take a 50K press to pop it back apart, where if the arbor is installed cold, it take only a few thousand pounds to break the seat.

And why the hell would you only have one chance? You aren't going to damage the steel, you can't even get close to annealing it in the temps your kitchen oven does, outside of the cleaning cycle.

Later,
Jason
 

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Bullshit. I have changed several ring gears this way. The flywheel has a lip machined, the ring gear has to sit tight on the lip. There are no shims to go in place. You heat it up and wack it down until it is seated in place. Machinists do this all of the time to get a semi-permanent fit with chucks and arbors. You can install a drill chuck arbor this way and it will take a 50K press to pop it back apart, where if the arbor is installed cold, it take only a few thousand pounds to break the seat.

And why the hell would you only have one chance? You aren't going to damage the steel, you can't even get close to annealing it in the temps your kitchen oven does, outside of the cleaning cycle.

Later,
Jason
OOPS. I stand corrected. I spoke based on what I have done which does not include what you describe. The things I have worked on where heat is involved to make it fit, you have one chance because as soon as the piece that is heated is in contact with the room temp piece, the heated piece cools and shrinks like right now. If it is not aligned propperly then you are screwed and both pieces are likely scrapped. The tolerences I have worked with have been so tight that there is no room for eror. But since you say there is a lip. then yes certainly it is do-able. The only thing I would add to throwing the gear in the oven, is to throw the other piece into the freezer to shrink it. Then when you go to drop the gear on, it will easily drop on and when the temps equalize, it will be set.
 

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OOPS. I stand corrected. I spoke based on what I have done which does not include what you describe. The things I have worked on where heat is involved to make it fit, you have one chance because as soon as the piece that is heated is in contact with the room temp piece, the heated piece cools and shrinks like right now. If it is not aligned propperly then you are screwed and both pieces are likely scrapped. The tolerences I have worked with have been so tight that there is no room for eror. But since you say there is a lip. then yes certainly it is do-able. The only thing I would add to throwing the gear in the oven, is to throw the other piece into the freezer to shrink it. Then when you go to drop the gear on, it will easily drop on and when the temps equalize, it will be set.
I agree with you, but we aren't comparing the same situation. Heat fitted interference parts are damn near impossible to get apart unless you have one mother of a press, and a good way to set up the part for the operation. You are also talking about something that is beyond the standard .001-.002" spec for interference fit. Something that is machined to these standards, and meant to be pressed together will easily come apart on a press. If you get much beyond .002" then even a press isn't going to put it together, and you have to resort to temperature differential if you want the parts to mate, in which case, you may never get it apart. The difference is that the ring gear is made to be replaceable, and the interference should be somewhere with in the spec. It is not going to shrink back smaller than what it was, so there is no harm in doing it. It will come apart again with either a press, or heating the ring gear and prying it off. The ring gears are steel and the flywheels are cast steel. The ring gear has much less mass than the flywheel, so you can easily heat it hot enough to pry it off before the flywheel gets hot enough to cause anything more than minimal expansion.

Tapers, and especially locking tapers are a whole different story. The reason a taper can lock up so hard when you install it in a heated socket is that is goes further into the mating taper than it was intended. It can indeed become a permanent fixture. I have a high end $380 drill chuck at home that the PO installed the arbor with this method. Jacobs chuck keys wouldn't even try to pop it. I brought it to work, and had them try to press it apart on a 50 ton press, we hit about 35 tons before I said screw it, I didn't want to ruin the chuck, so I ended up buying an adapter.

There are lots of ways to reach the same end, that is why I mentioned the availability of a replacement flywheel for a reasonable price. I however like to go the least expensive route, even if it takes a bit more work, so that is why I explained the process. Maybe I was being somewhat flippant when I said, drop it on, and it is fixed. It can indeed take a lot of work to get it one, but some of them aren't bad at all.

Later,
Jason
 

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Replaceing the ring gear is not hard at all like bigblockbugy described. The only thing I do diffrent is that I put the flywheel in the freezer for a couple hours also. I dont know what the diffrence is compared to not doing this but thats how my Farther showed me and I have just always done it that way. Good luck.
 

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Discussion Starter #9
It's an auto so I suppose it's technically a FlexPlate, my apologies. To replace it the engine needs to be fully pulled, correct? IIRC, there are 4 big bolts at the center on the back that need to come off for it to be replaced?
 

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I agree with you, but we aren't comparing the same situation. Heat fitted interference parts are damn near impossible to get apart unless you have one mother of a press, and a good way to set up the part for the operation. You are also talking about something that is beyond the standard .001-.002" spec for interference fit. Something that is machined to these standards, and meant to be pressed together will easily come apart on a press. If you get much beyond .002" then even a press isn't going to put it together, and you have to resort to temperature differential if you want the parts to mate, in which case, you may never get it apart. The difference is that the ring gear is made to be replaceable, and the interference should be somewhere with in the spec. It is not going to shrink back smaller than what it was, so there is no harm in doing it. It will come apart again with either a press, or heating the ring gear and prying it off. The ring gears are steel and the flywheels are cast steel. The ring gear has much less mass than the flywheel, so you can easily heat it hot enough to pry it off before the flywheel gets hot enough to cause anything more than minimal expansion.

Tapers, and especially locking tapers are a whole different story. The reason a taper can lock up so hard when you install it in a heated socket is that is goes further into the mating taper than it was intended. It can indeed become a permanent fixture. I have a high end $380 drill chuck at home that the PO installed the arbor with this method. Jacobs chuck keys wouldn't even try to pop it. I brought it to work, and had them try to press it apart on a 50 ton press, we hit about 35 tons before I said screw it, I didn't want to ruin the chuck, so I ended up buying an adapter.

There are lots of ways to reach the same end, that is why I mentioned the availability of a replacement flywheel for a reasonable price. I however like to go the least expensive route, even if it takes a bit more work, so that is why I explained the process. Maybe I was being somewhat flippant when I said, drop it on, and it is fixed. It can indeed take a lot of work to get it one, but some of them aren't bad at all.

Later,
Jason
Dayum, very well put. Even a novice can understand that. Did you get some of that from the internet (copy and paste) or do you actually know all that technical stuff?
It's an auto so I suppose it's technically a FlexPlate, my apologies. To replace it the engine needs to be fully pulled, correct? IIRC, there are 4 big bolts at the center on the back that need to come off for it to be replaced?
You may not have to fully pull the motor. As long as you can access the bolts and drop the flexplate.... that is all you are after.
 

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It's an auto so I suppose it's technically a FlexPlate, my apologies. To replace it the engine needs to be fully pulled, correct? IIRC, there are 4 big bolts at the center on the back that need to come off for it to be replaced?
No, the engine does not need to be pulled. The transmission does, however, have to be removed or at least supported and pulled back. The method I have found to work best is to buy 4 bolts the same thread as your bellhousing to engine bolts. You want the bolts to be at least about 8"s long. I think that the ford small block bolts are 7/16-14. If bolts are too expensive, but a long enough piece of all-thread from the hardware store, cut it up, and put double nuts on one end. You want to replace at least two opposing bellhousing bolts with the threaded rod, 4 would be best, but sometimes you cant get them in. Support the back of the trans/transfer case with a floor jack, and remove the transmission mount bolts and the remaining bell housing bolts. Slide the trans back on the threaded rod until you have enough room to work. The beauty of this method is it keep everything very well aligned so it will take minimal adjustment to get the trans to mate back up. It is IMO the best way to install a manual trans, as you can slide it onto the threaded rod, throw your nuts on to keep it from sliding back off, and easily line the input shaft up and slide it home, but it works equally well to do work like you need to do without completely removing the engine or trans.

Anyhow, things you need to be aware of. If you do this, you may want to support the front half of the trans as well, a jack stand or something for safety. Especially if you cant get 4 rods in. You need to remove the nuts securing the torque converter to the flex plate before you slide anything. It isn't all that fun to do, working between the engine and flywheel, but it can be done. If you dont, the torque converter will stay on the flex plate and your trans will run fluid all over the place. Add to that, that there is a very specific way to reinstall a converter w/o damaging the front pump, that you are better off leaving the converter w/ the trans. There should be 5 bolts holding the flex plate to the crank shaft. The new flex plate will only line up one way, the bolt circle is asymetrical. And last, you may not know, but if you pull up your carpet in the cab, there is an access panel in the transmission tunnel that will make reaching the upper bellhousing bolts a much easier experience. Go buy a haynes manual and it will have a good description of the process you are about to endure. It would probably only take someone with experience and all the right tools a couple of hours, but if it is your first time, I would plan on a whole weekend job.

BTW, I may not have been clear in my first post, but a flex plate's ring gear is not replaceable. It is welded in place, but flex plates are cheap enough that it wouldn't be worth trying to replace it anyhow.

Later,
Jason
 

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Discussion Starter #12
No, the engine does not need to be pulled. The transmission does, however, have to be removed or at least supported and pulled back. The method I have found to work best is to buy 4 bolts the same thread as your bellhousing to engine bolts. You want the bolts to be at least about 8"s long. I think that the ford small block bolts are 7/16-14. If bolts are too expensive, but a long enough piece of all-thread from the hardware store, cut it up, and put double nuts on one end. You want to replace at least two opposing bellhousing bolts with the threaded rod, 4 would be best, but sometimes you cant get them in. Support the back of the trans/transfer case with a floor jack, and remove the transmission mount bolts and the remaining bell housing bolts. Slide the trans back on the threaded rod until you have enough room to work. The beauty of this method is it keep everything very well aligned so it will take minimal adjustment to get the trans to mate back up. It is IMO the best way to install a manual trans, as you can slide it onto the threaded rod, throw your nuts on to keep it from sliding back off, and easily line the input shaft up and slide it home, but it works equally well to do work like you need to do without completely removing the engine or trans.

Anyhow, things you need to be aware of. If you do this, you may want to support the front half of the trans as well, a jack stand or something for safety. Especially if you cant get 4 rods in. You need to remove the nuts securing the torque converter to the flex plate before you slide anything. It isn't all that fun to do, working between the engine and flywheel, but it can be done. If you dont, the torque converter will stay on the flex plate and your trans will run fluid all over the place. Add to that, that there is a very specific way to reinstall a converter w/o damaging the front pump, that you are better off leaving the converter w/ the trans. There should be 5 bolts holding the flex plate to the crank shaft. The new flex plate will only line up one way, the bolt circle is asymetrical. And last, you may not know, but if you pull up your carpet in the cab, there is an access panel in the transmission tunnel that will make reaching the upper bellhousing bolts a much easier experience. Go buy a haynes manual and it will have a good description of the process you are about to endure. It would probably only take someone with experience and all the right tools a couple of hours, but if it is your first time, I would plan on a whole weekend job.

BTW, I may not have been clear in my first post, but a flex plate's ring gear is not replaceable. It is welded in place, but flex plates are cheap enough that it wouldn't be worth trying to replace it anyhow.

Later,
Jason

Wow, thanks a ton! A lot of weight off my chest knowing I don't have to pull this damn engine again. I have all the good Ford service manuals so I will definately do some digging in them this weekend to prepare for the job next weekend.
 

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Dayum, very well put. Even a novice can understand that. Did you get some of that from the internet (copy and paste) or do you actually know all that technical stuff?
Thanks. Nope, no cut and paste. I am an amateur machinist, so I read a lot. I have no formal education in this stuff, but I tend to research the hell out of things, especially when it comes to machining any particular project. Needless to say I have a lot of similar useless information floating around in my head. A lot of stuff you have to know for even simple machining if you want your parts to fit right. I do my best to explain things as simply as possible, because it was not that long ago that I was teaching myself.

Later,
Jason
 

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Thanks. Nope, no cut and paste. I am an amateur machinist, so I read a lot. I have no formal education in this stuff, but I tend to research the hell out of things, especially when it comes to machining any particular project. Needless to say I have a lot of similar useless information floating around in my head. A lot of stuff you have to know for even simple machining if you want your parts to fit right. I do my best to explain things as simply as possible, because it was not that long ago that I was teaching myself.

Later,
Jason
If you ever want to teach, you sure know how to explain stuff very well and I think you would be good too.
 

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If you ever want to teach, you sure know how to explain stuff very well and I think you would be good too.
I agree with Walt, and thanks for clearing up the flexplate part.
 

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