Balance????

PostPost by: nomad » Sat Nov 14, 2015 4:31 pm

I've rebuilt my S1 engine [four bolt crank] without doing an engine balance. The car is intended for the street only so I figured there was no need. I then replaced the ring gear on my flywheel and replaced the four tack weld's that secured it to the flywheel. I now am concerned about balance on the flywheel. By eyeballing the welds they appear to be of equal weight but I'm wondering if I should be concerned or not.

Unfortunately my engine builder can not balance the flywheel without balancing the whole crank/flywheel assembly.

What think thee, group??? :roll:

Maybe an twin cam specialist might be of help? Suggestions??

Kurt
26/3754
nomad
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1060
Joined: 05 May 2012

PostPost by: 512BB » Sat Nov 14, 2015 5:45 pm

Kurt,

If you had two twin cam engines that were identical, one having been balanced and the other not, you could definately tell when driving, which engine you had in the car.

The differences between the individual weights of the welds on the flywheel / ring gear will be fractions of a gram and you will notice nothing. If you have not had the engine balanced before, the differences between the con rods will be far greater. Don't worry about it, do it next time.

Leslie
512BB
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1254
Joined: 24 Jan 2008

PostPost by: nomad » Sat Nov 14, 2015 6:40 pm

Thanks, Leslie...the thing that concerned me was that the imbalance would be quite a ways from center line.

I guess clutch wear could make it off that much.

Kurt.
nomad
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1060
Joined: 05 May 2012

PostPost by: elj221c » Sat Nov 14, 2015 8:33 pm

My concern would be....

Why is the ring gear welded on?

It should be shrunk on.

Shouldn't it?
Roy
'65 S2
User avatar
elj221c
Fourth Gear
Fourth Gear
 
Posts: 539
Joined: 12 Sep 2003

PostPost by: nomad » Sat Nov 14, 2015 11:30 pm

elj221c wrote:My concern would be....

Why is the ring gear welded on?

It should be shrunk on.

Shouldn't it?


In the past that is what I have always encountered but this ring gear was a heat shrink fit plus having four tack welds, Appears that the car was low mileage and I suspect it was factory done.

Kurt.
nomad
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1060
Joined: 05 May 2012

PostPost by: Chancer » Sun Nov 15, 2015 8:18 am

A common racing mod especially with a lightened flywheel, its belt and braces but they have been known to come loose especially if (over) heated with an oxy/acetylene torch for fitting.

The inertia starter mechanism will try to dislodge the ring gear.

The weight of the welds will not register on a balancing rig although I agree their moment of inertia is far more than the same mass on the crank or rods.
Chancer
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1132
Joined: 20 Mar 2012

PostPost by: Elanconvert » Sun Nov 15, 2015 10:07 am

I'm surprised the engine builder didn't balance everything as a routine.......
when I did my imp engine, i had it all done including full assembly with clutch cover etc.
deffintely advisable when revving to 10k..... :wink:

:D fred :D
'Never give up!....unless it's hopeless.....'

1970 S4 dhc big valve
1973 Ginetta G15
1967 Ginetta G4 [sadly now sold]
1959 lotus elite type 14
Elanconvert
Third Gear
Third Gear
 
Posts: 344
Joined: 26 Jul 2013

PostPost by: Elanconvert » Sun Nov 15, 2015 10:08 am

I'm surprised the engine builder didn't balance everything as a routine.......
when I did my imp engine, i had it all done including full assembly with clutch cover etc.
deffintely advisable when revving to 10k..... :wink:

:D fred :D

bit of an echo here.....how do you delete duplicated posts?
Last edited by Elanconvert on Sun Nov 15, 2015 10:14 am, edited 2 times in total.
'Never give up!....unless it's hopeless.....'

1970 S4 dhc big valve
1973 Ginetta G15
1967 Ginetta G4 [sadly now sold]
1959 lotus elite type 14
Elanconvert
Third Gear
Third Gear
 
Posts: 344
Joined: 26 Jul 2013

PostPost by: nomad » Sun Nov 15, 2015 4:48 pm

I've fitted quite a few ring gears over the years and always used a oxy acetylene torch. The technique I used on this one was to leave the flywheel outside overnight in the winter snow. I then heat around the entire gear and use the "spit" test to determine how hot the ring gear is getting. How fast the spit sizzles off is a pretty good indication of how hot you have it! :D [ Farmer at work here!]

Kurt.
nomad
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1060
Joined: 05 May 2012

PostPost by: john1180 » Sun Nov 15, 2015 5:09 pm

I think that's the "Dakota" method as opposed to the "Minnesota" method that requires an ice fishing house, a hot wood stove, and cold beer!
john1180
Second Gear
Second Gear
 
Posts: 108
Joined: 07 Feb 2005

PostPost by: nomad » Mon Nov 16, 2015 1:50 am

john1180 wrote:I think that's the "Dakota" method as opposed to the "Minnesota" method that requires an ice fishing house, a hot wood stove, and cold beer!


Ah, yesss....I forgot about the need for a cold beer. Holds true in Dakota as well! :D

Kurt.
nomad
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1060
Joined: 05 May 2012

Total Online:

Users browsing this forum: No registered users and 39 guests