390 flywheel on a 1978 460

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Old 04-20-2006, 05:35 PM
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390 flywheel on a 1978 460

I just finished putting a 1978 460 with a heavy-duty (1 ton) ZF 5-speed in my 1970 F100. With the 3:50 rear gears, it is awesome. Plenty of power off the line and a great overdrive.

I understand that the pre-1979 460's were neutrally balanced, as are the 390's.

Since I couldn't find a reasonably priced neutrally-balanced 460 flywheel, I used a 390 flywheel and pressure plate with a 460 11" clutch disc. The engine is balanced just fine - no vibrations. But I have what I hope is a small problem.

The 460 starter doesn't seem to engage the ring gear correctly. It will turn the engine over, but it sounds terrible while doing so, and it makes a horrible grinding noise when disengaging once the engine starts, like the bendix is not retracting quickly enough.

I've already replaced one brand-new starter that had the bendix spring break.
I thought the 390 and 460 had the same number of teeth on the ring gear (184), but it sure doesn't sound like mine are matched. Either that or the starter is not engaging completely. The number of teeth on the starter is 9.

Has anyone had any experience with this problem?

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Old 04-20-2006, 09:06 PM
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Sounds like the starter bendix may be going in too far on the ring gear. you might try spacing the starter out a bit and see if it helps.
 
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Old 04-20-2006, 09:35 PM
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. . .Your not using a late model 460 starter are you? Since the flywheel on the later models sat father out, maybe the starters had a deeper reach into the bellhousing?
 
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Old 04-21-2006, 12:41 AM
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you did use the block plate between the block and bellhousing didn't you? I have seen people not put that in, and it acts as a spacer. Also I am not 100% sure on this but if I remember correctly the 390 flywheel does work but you have to put a spacer behind it as I don't believe it's set quit as deep as the 460 flywheel, but thats something someone else hopefully remembers better than me, it's been a long time since I messed with that swap (as in about 25 yrs.)
 
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Old 04-21-2006, 09:16 AM
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I'm using the early-style starter (solenoid on inner fender). I picked up the later-style starter from my parts person and compared it to the early model. The bendx housing appears to be the same length, and the number of teeth are the same, nine (9). The only difference I can see is that the solenoid is mounted on the later-model starters rather than on the inner fender.

I was not aware of the need for a spacer between the flywheel and the crankshaft, so, no, I didn't install on. Do you think that the bendix is traveling beyond the ring gear,? I think I can check that by having someone bump the starter while I watch the amount of mesh from below.

If a spacer is needed, what does it look like, and where do I find one.

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Old 04-21-2006, 09:41 AM
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You may have to make one yourself, I'm not too sure what is out there for starter spacers/shims. I know I have used one in a big block chev race motor, so you might look at some of the drag racing parts suppliers?
 
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Old 04-21-2006, 12:10 PM
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Thanks for the help and advice, everybody. I really appreciate it.

I have decided to do what I should have done before I installed the engine in the truck. I will check the travel of the bendix gear as measured from the starter mounting surface, and compare that with the distance from the bellhousing spacer to the ring gear. Since the starter mates directly against the spacer, this should give me a good idea how well the ring gear is meshing with the starter gear.

Thanks again,

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Old 04-21-2006, 12:17 PM
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The FE had 2 different styles of flywheels a 164 and a 184 make sure you don't have the 164.
 
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Old 04-22-2006, 01:56 AM
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Any chance you have an automatic starter by mistake?The auto vs standard are not interchangeable.
 
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Old 04-23-2006, 08:01 PM
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Count the teeth on the flywheel. You need 164 and a 9 tooth bendix!
 
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Old 04-26-2006, 07:48 PM
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eedvark, I checked with my parts person, and he tells me that, for the 1978 460, the same starter is used for both the automatic and the manual trannys.

William, the research I have done shows a 164 tooth ring gear for the 460, but not for the 390. I also found that a 176 tooth and a 184 tooth ring gear is available for the 460. The data also shows a 176 tooth and a 184 tooth ring gear for the 390.

I had my parts person pull a 1978 460 ring gear from stock and it had 184 teeth, as does my 390 flywheel. And they are the same diameter (laid the 460 ring gear over the 390 and saw no difference).

If the 164 tooth ring gear is standard for the 9-tooth bendix, why do you suppose the parts store stocks the 9-tooth starter with the 184-tooth ring gear. Can you clear up my confusion?

Also, what years 390 and/or 460 used the 164-tooth ring gear (so I will know what to ask for)? Is there a list somewhere that tells what ring gear (number of teeth) goes with what bendix (number of teeth)?

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Old 04-27-2006, 01:02 PM
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When I did my swap on my 70 F-250 I used a flywheel from a 1970 360 FE for my internally balanced 460. I used a starter from a 1985 F-250 460. I had to shim my starter to compensate for the 3/8'' spacer plate that I built to put between the engine block and bellhousing. I would say you either have a mismatched ring gear/starter problem or a starter clearance problem. To fix the clearance problem just use some washers to shim the starter to figure out how much distance is needed, then I would recommend getting a proper shim built from sheet steel by a machine shop or do it yourself like I did with a plasma cutter.
 
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Old 04-27-2006, 06:51 PM
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Thomsen,

I'm using a 390 flywheel with a 11" 390 pressure plate and a 460 disk.
I pulled the engine/transmission out yesterday and, with it hanging on the engine hoist, energized the starter to check gear mesh.

On initial contact, the bendix gear will fully mesh with the ring gear, but the teeth do not match. Once the starter/engine begin to turn, the starter gear tooth hits the top of the next ring gear tooth. It will catch enough of the tooth to continue turning the engine, but the mesh is way off.

To me, this indicates that the 184-tooth ring gear is wrong for the 9-tooth bendix gear. My problem is that I don't know if the 9-tooth bendix requires a 164-tooth ring gear or a 176-tooth ring gear. I hate to buy another ring gear, have it installed on the flywheel, and find that it is wrong, too.

And, as I said in an earlier post, the parts stores stock the 9-tooth starter which they say matches the 184-tooth flywheel. This is really confusing me
since I have visually seen the gear mismatch.

That's why I was asking if anyone knew which ring gear went with which bendix gear (no. of teeth vs no. of teeth).

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Old 04-28-2006, 08:41 AM
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Could you use a 390 starter bendix on the 460 two bolt starter? Can you move a 164 tooth ring gear to the 390 flywheel and have it rebalanced? Than again maybe the 460 164 tooth flywheel would be a better deal even if it costs a bit more? Wish I could be more helpful!
 
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Old 04-28-2006, 12:41 PM
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I don't know either ...

In my experience (don't start shooting at me yet) if you put the smaller flywheel in the bigger bell the starter will not even touch the flywheel.The distance the starter is moved out in an arc is much larger than the lenth of a flywheel tooth.

I've always used auto starters with auto and standard starters with standards. Funny the 351M 351W and everything but the 400 and 460 show a different part number in the LMC catalog for auto vs standard starters.I laid in a friends snowy driveway one Friday night and put 5 starters on a 351W till I got one that didn't grind the teeth It was the only automatic one he had.I know where it came from cause I pulled it off a car.Just my thought but try an auto starter and a standard starter from a 351M .Why would a 351M call for different part # starters and a 400 and 460 not?They bolt to the same transmissions.
 

Last edited by eedvark; 04-28-2006 at 12:46 PM.

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