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Has anyone ever attempted to remove the flywheel ring gear?
I have decided to use an aluminum 90-96 Nissan 300zx n/t flywheel for the Alfa-Nismo transmission project. Since the Nissan flywheel is a only a touch larger than the Alfa flywheel I will have it turned down and then install the alfa ring gear to the Nissan Flywheel.
In theory I make it sound simple... perhaps just vague , but how does one go about removing a ring gear, and once it is off how do you put it back on?
To what tolerance should the flywheel be machined so as to get a good press on fit , and once the ring gear has been pressed on how should it be secured (keep in mind the flywheel is made of al?
Vittorio

If I'm not mistaken the ring gear is a heat shrink fit. You may have to have the old flywheel machined out from under the ring gear then heat the gear and slip it over top of the new flywheel.

You will want .005 to .008in. interference I think......check with your local machinist( I don't have my handbook here, its at work).

You will also want to bolt / pin the flywheel and ring gear together. Here you will drill and tap the parting line of the flywheel/ ring gear....also counterbore for the socket head cap screw that you use. Use at least 3 bolts, evenly spaced. Then get the assembly balanced.

HTH,
Scott

I had them off several times when I lightened the flywheels. It's just a tight fit.
Put something sharp (not your head) between the FW and the ring and hammer it out.
Getting it back in you can help with some temperature difference.

To unfit the ring, as described above just need to be heated a bit with flamme (no need to be red ! just heated a bit...200°C is almost sufficient...) and hammer it out.


about the tolerances....
i do it a number of times.
this is veryt tigth !
when its build it is in mm, there is a 0.20 to 0.25 mm of tighten, its very high... i mean that the ring diameter is smaller than the flywheel diameter.
when you heat her she grows up, then fit, and when it cold down it release and hold on.
in most common of time very tigthen is 0.15 to 0.18 mm for a such size, but for this it appears very large...also fitted in a alloy flywheel we are somewhere afraid by a collapse somewhere.

its a tighten tolerance with the 0 on the flywheel.
the flywheel is 257 h6:
257mm +0
............-0.03
and the surface finish must be:
Ra 0.6 to 0.8
(with this, and above you dont need to put screws or thing else to tigthen him in place)

sorry guy i dont know more about us standarts...
old ring when dismantled had
257mm -0.020
............-0.025
i check this of 3 dismantled rings..so it must be correct.

if you did a complete custom thing, you can reverse the ring to get the unused tooth engagement side.

where is was working on past, they had a lot of machining capacity, i measure it with a 3axis mesure machine from mitituyo, i had a do a such of thing with this it was great.
it is always great...when you can do it free, now i had to pay serious prices


also if you fit it in a alloy flywheel...it is possible that you can never pull it in the future, because of alloy flywhell grow up faster than ring when you heat them.
if you try you can damage the both...(perhaps ! but probable...)

I never used heat to get it out.
I don't even recall using heat to get it in.
A hammer for sure but heat

Micke wrote:I never used heat to get it out.
I don't even recall using heat to get it in.
A hammer for sure but heat

i never try with heating...it looks like to fit to.

but when you refit this with heating..the hammer is not needed !
just heat...200°c in the same applepie heater, and the ring drop in...simply, no need any hamerin.
try it the next time...(degrease seriously)...the first time when i open the door of the oven, the kitchen was under smoke
miss doesnt feel that like a joke

hahaha... flywheel casserole! so if i get this right i should be able to machine the flywheel down to this tolerance and not have to use any other means to secure the ring gear:

the flywheel is 257 h6:
257mm +0
............-0.03
and the surface finish must be:
Ra 0.6 to 0.8

Vittorio

hum...i had make on past 2 flywheel.
and fit and unfit number of times (unfit only in steel and iron ones)

one in steel...i do the things above...

the one in alloy, i fit 3 pins at 120°...to be quiet.(its fast...1hour labor with minimum tools)

True that with only the starting load on the flywheel you wouldnt need the extra strengh of the bolts I described. (overkill on my part)

A help with the heat of the ring is to freeze the flywheel to shrink it.

be sure to take your measurements with the ring and flywheel at close to the same tempreature. Room temp will be fine, but a hot flywheel on the lathe WILL measure big.

hth
scott

MR2 Zig wrote:True that with only the starting load on the flywheel you wouldnt need the extra strengh of the bolts I described. (overkill on my part)

be sure to take your measurements with the ring and flywheel at close to the same tempreature. Room temp will be fine, but a hot flywheel on the lathe WILL measure big.

hth
scott

yes, im agree with you about any pins or screws...uselaess until the rest is done perfectly.
i did it a long time ago, after that, skills tell me it.

nice tip, to think at the temperature of the alloy when mesure it during process on lathe.


Sporttunner,...With all that you are ready do make your in mind flywheel...
you are going to fit the nissan gearbox ? (the engine to ? should be powered interesting... )