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#1 Flywheel Clutch Balance.

Posted: Fri Oct 20, 2017 2:31 pm
by mikebryan
I am rebuilding my S1.5 engine. The work so far involved rebore, new Mahle pistons, crankshaft polished and dynamically ballanced plus new timing chains etc. The engine has been assembled so far that the next job is to mount the Flywheel and clutch. When I disasembled these, the relative positions of each component was marked.
According to my workshop manual the clutch should be marked with a "B" which should be alined with the "B" on the flywheel. My clutch has no such mark.
I can rebuld the various components according to the marks I made before the strip down BUT, how do I know if the " non OEM " clutch " was ever balanced to the Flywheel and how can I check now that the engine is partially rebuilt.
My Work Shop Manual suggests setting the clutch/ flywheel assembly on "parallel knife edges" then drilling into the Flywheel to balance. Has anyone done this work or is it only possible when the Flywheel is attatched to the Crankshaft before the assembley is mounted into the Block ???
Any help would be appreciated

Thanks
Mike

#2 Re: Flywheel Clutch Balance.

Posted: Fri Oct 20, 2017 10:44 pm
by abowie
My machinist usually takes the flywheel and clutch and balances them for me. I'm not sure if these are done separately or as a unit with the crankshaft.
This is not a difficult job and if your shop can balance a crank they can do it for you. They will mark the clutch for reassembly.

#3 Re: Flywheel Clutch Balance.

Posted: Sat Oct 21, 2017 9:06 am
by 265bhp
Hi
+1 on the advice from Andrew, have a look at my rebuild thread

viewtopic.php?f=8&t=8415

M
Alignment marks are easily arranged....you should also have your pistons and con rods balanced and weighted...I had to return one of my pistons as it was way out of the weight range of the other 5, and you can see from the photos that all the con rods needed adjustment

Hope that helps

Jonathan

#4 Re: Flywheel Clutch Balance.

Posted: Sat Oct 21, 2017 9:52 am
by E600
Hi
From reading the original it appears the clutch cover that came off is the one going back on. If so I would highly recommend a new 3 piece clutch be fitted. If I have read this wrong then sorry please carry on.

Regards
Pat

#5 Re: Flywheel Clutch Balance.

Posted: Sun Oct 22, 2017 9:02 am
by PeterCrespin
".. BUT, how do I know if the " non OEM " clutch " was ever balanced to the Flywheel"

You don't know.

"... and how can I check.."

You can't check.

Sadly, because your engine block is built you only have one question to ask yourself:
"Do I have the time/money/energy to strip my engine totally, on the off-chance the engine smoothness will be enhanced enough for me to notice, or to benefit in reliability terms?"

The I-6 is inherently highly balanced and depending on your planned use will probably be sufficiently smooth and durable without a total stripdown.

Next time give the machinist the crank, damper, flywheel and clutch which they will re-balance to zero as each new part is added. Unless you plan frequent sustained high speeds (that can set up damaging torsional harmonics) you can just finish building the engine IMO. But as Pat pointed out, unless you know for a fact the clutch had bags of life left in it, your best bet is to replace this 'consumable' whilst it is accessible.

#6 Re: Flywheel Clutch Balance.

Posted: Sun Oct 22, 2017 6:30 pm
by mikebryan
Thanks guys for all of your informed imput, really appreciated.

#7 Re: Flywheel Clutch Balance.

Posted: Wed Oct 23, 2024 8:53 am
by maycee28
Hello
I face a similar problem on my 1962 E type 3.8. The flywheel (part no C23455) is machined all over and has no balance point marked (possibly inherently balanced ?). It seems to be quite well balanced, as far as I can tell. I think later engines had balance markings and engine numbers stamped on them. The clutch pressure plate does have small balance weights riveted to it and a B stamped on it, but despite this, it does not seem very well balanced. Perhaps these components go out of balance with wear ?
I believe the balance markings should be at B.D.C. when pistons 1 & 6 are at T.D.C. but I can't quite understand why the orientation matters if these parts are balanced. If anyone knows I would love to know.
John

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