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Worn Flywheel on 470

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aussie_trev

New member
I have recently removed the fl

I have recently removed the flywheel off both of my engines and have found that they have worn teeth on the ring gear 180 degrees apposed I suspect this is caused by the compression of the engine. I would like to rotate the flywheels 90 degrees so I do not cause any more ware. Question is would the maximum load be at top dead centre??? Thanks Trev.
 
"Ayuh,......

While I don&#3

"Ayuh,......

While I don't do 470s,......
Most of the motors I've had apart don't allow the rotation of the Flywheel do to Balance Issues......
But,......
You can knock the Ring Gear off the flywheel,+ flip it over to the fresh side.....
Just knock it off with a hammer,+ brass drift,...
Then heat it in an Oven,+ drop it back on, Upside Down......"
 
"Trevor...
I agree with Bondo

"Trevor...
I agree with Bondo that due to bolts patterns you probably cannot rotate the position of the flywheel. You might find that the ring gears are welded on in a few spots around the flex plate. If thats the case, you'll be looking for some different ones - new or good used. You may want to put new drive pinions on the starters though. They get worn out too and cause wearing of your new ring gears.

Wrench"
 
I would put a starter and a fl

I would put a starter and a flywheel on it and be done vs trying to save a few bucks and risk having to take it apart again later.

Yes... flywheel stop turning at one of two (or 4 depending on the engine) places in terms of degree clocking on the crank.
 
"Trevor
I would put a dial g

"Trevor
I would put a dial gauge on the flywheels and check the run out. 180 degree damage may indicate a mis- installed, warped or foreign object between the crank and flywheel.
Bert"
 
the engine stops turning in on

the engine stops turning in one of two positions due to compression et al. Therefore the wear spots from a misaligned starter show up 180 degrees out from one another.
 
"Mistahays
After working on b

"Mistahays
After working on both automotive and aircraft engines with thousands of hours on the ring gears, I've never noticed this phenomena.
Bert"
 
"Trevor...
Unless that thing

"Trevor...
Unless that thing is a single cyl., the engine will stop in any one of a hundred places. I could see if it was a lawnmower engine that it might stop in the same place all the time because of the piston coming up on the compression stroke, but a multi cyl engine will stop anywhere. Bert has a good point about a warped flywheel leaving wear marks at 2 opposite spots on the ring gear.

Wrench"
 
"Thanks all for your input. Th

"Thanks all for your input. The flywheel on the 470 is drilled evenly with no dowel so can be rotated. I have 3 flywhhels off 3 different motors all with the same ware. 1 is unserviceable after 20 years so fitting the 2 best ones and re-alining 90 degrees should give me many more years. Most non performance engines as these would be are balanced as individual components not as an assembly, therefore, it should not efect the balance of the engine. Bert were you saying you have never wittnessed this type of ware?"
 
"Trevor
Strange, I don't

"Trevor
Strange, I don't know what to tell you. The ring gear is only used to start the engine and then disengaged.
I'm lost. Unless it's an anomily
biggrin.gif

Bert"
 
"Trev...
I just did a google

"Trev...
I just did a google earth on Lake Macquarie. I was checking out all the boats in the bay and figured that one of them must be yours. I can't see the wear on the flywheels from here.


Wrench"
 
"No expert on 4 bangers, but V

"No expert on 4 bangers, but V-8's always have four equally spaced distinct wear patterns around the ring gear, and V-6's have three.

It seems that engines will always stop rotating in one of these different positions when shut off. This position is likely where the next cylinder is coming up on compression, but there is no power to drive it up to TDC, so it just coasts to a stop there. If the cylinder has enough pressure built up to overcome the rotating friction at the point where it stops, then it will rotate the crank backwards until the pressure bleeds off, near BDC.

Since a V-8 has 4 compression strokes per rev, and a V-6 has 3, it follows that they will likely always stop in one of these 4 or 3 positions, plus or minus a few degrees. And that's where the starter pinion slams into the ring gear on the next startup.

It's understandable that 4 bangers will have two preferential positions around the ring gear, since there are 2 compression strokes per rev. I don't think the wear that you are seeing is odd at all.

Rod"
 
"Rod your are on the right tra

"Rod your are on the right track, however, the flywheel is drilled with an offset hole so it can not be rotated. I do have one with very little ware so I will fit that one and see how many years I get. I will in the mean time import a new ring gear and a new drive pinion for the starter.
Thanks for all the ideas.
Trev"
 
"Wrench

You need to look cl

"Wrench

You need to look closer, its parked in his yard at present, maybe I could send you the co ordinates so you could zoom in. I could say it spends alot of time there but he would probably throw something at me.

On the rotation issue, I have always generaly found that engines do tend to stop in around the same areas all the time, I agree with Rod and Trev on this one, the wear paterns generally displayed are 2 spots for a 4cyl, 3 spots for a 6cyl, 4 spots for an 8cyl and so on.

Peter C"
 
Right on. So my comment about

Right on. So my comment about 2 points 180 degrees out reflects my experience on mostly 4 cylinder (honda/volvo) cars. 3 and 4 points on v6/v8 makes sense. interesting conversation.
 
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