Weld-on crank balance weights

ppower

ppower

Member
Has anyone experience of fitting the weld-on weights to produce a counter balanced crankshaft?
If so did it distort the crankshaft ? (The existing crankshaft is running true and does not need regrinding.)
Has anyone first hand experience of the benefits/problems?
Thanks
 
I have considered adding counterweights to a crankshaft but won't weld them on. I will have weights profile cut with a loop that goes all the way around the "flanges" on the shaft where the weights will attach. These "loops" will be shrunk on and have provision for a hole drilled into the flange where there is no stress and a high tensile bolt put in. 2 per weight. Quite secure and no welds.
I intend having the flanges ground for a good surface onto which I will shrink the weights and the middle two will be about 10 thou larger than the end two so that the weights can be threaded on while cold.
I have given this considerable thought and discussed it with knowledgeable people. While my thoughts might worry some :D, if you PM me, I'll be happy to discuss it with you. If you have Skype loaded on your computer, that would be even better.
 
I intend having the flanges ground for a good surface onto which I will shrink the weights and the middle two will be about 10 thou larger than the end two so that the weights can be threaded on while cold."END QUOTE"

That won't work Mr.Synchro, you have to cut number 4 first, and then 3,2, and 1, last, and assemble, 4, 3, 2, 1.

The weights don't need bolts, two 3/16 pins are are good enough, and they don't even need that. Then just air hammer the holes shut, just like Fords.

Weights should be 5/8's thick.

Herm.
 
Dan Price makes them. see his WEB site.
Crankshaft Counterweights Set of four crankshaft counterweights, made just like Ford made them. Sweat them on, no welding needed. Machining required to fit Model A or B cranks. $425.00*
 
Kohnke Rebabbitting said:
I intend having the flanges ground for a good surface onto which I will shrink the weights and the middle two will be about 10 thou larger than the end two so that the weights can be threaded on while cold."END QUOTE"

That won't work Mr.Synchro, you have to cut number 4 first, and then 3,2, and 1, last, and assemble, 4, 3, 2, 1.

The weights don't need bolts, two 3/16 pins are are good enough, and they don't even need that. Then just air hammer the holes shut, just like Fords.

Weights should be 5/8's thick.

Herm.
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Herm and Forever, Thanks for the heads up. I would have picked that up when I had the crank shaft in front of me. I guess it's because the flywheel flange is bigger than the one onto which the weight will go. The "flanges" will grade from largest to smallest back to front. Gotchya!
5/8 material hasn't been available for decades here. 15mm is only about 25 thou less and I intend adding another weight of 13 or 14 mm to the side of that with dowels and bolts.
 
Yes, we have had several cranks fitted with welded-on weights. They work fine. Crank may have to be turned to due to distortion caused by welding in order to straighten it.
 
MAG Thanks that was the information I was seeking.
I know that I am going to have to grind number 4 big end journal, but if all the other journals and bearings are sound, I think I will not bother with the weld on weights. The extra machining and bearing casting would make it an expensive job.
 
. You would do better to find a Model B Counter balanced Crank and turn the bearings surfaces down to Model A Spec's They can still be found in the UK as Ford was fitting the Model B engines in trucks after WWII so they are a bit easier to find here than in the USA.
They even fitted the C/b crank in the 14.9 Small bore engine as used in cars and light vans

John Cochran
 
juke joint johnny said:
. You would do better to find a Model B Counter balanced Crank and turn the bearings surfaces down to Model A Spec's They can still be found in the UK as Ford was fitting the Model B engines in trucks after WWII so they are a bit easier to find here than in the USA.
They even fitted the C/b crank in the 14.9 Small bore engine as used in cars and light vans

John Cochran
Click to expand...

Do you have any idea where I might find a Model B counter balance crank?
 
I would try Bert's in Denver. They have lots of surplus. Also, Arizona Model A Center. Should be able to find a cheap runout B crank in those shops. Great way to get a std size cntrwtd crank. Make sure the crank grinder takes out the rear oil slinger and polishes the seal surface. Get ahold of the Model A rear seal of your choice for the dimension of that turning. Pretty critical.
Also, make sure the grinder cuts the correct radius on the ends of the rear main journal so the thrust surfaces match up. Good luck...I got one!
 
I have welded Piranio type weights to 10 MA & 2 MB cranks using mild steel rods after Veeing the weights and the crank circles in the areas to be welded without any distortion to the crank at all. They are all currently in running engines.
 
We have had counter weights water jet cut and welded them on. Some were spot on
and some needed turning anyway and some were just straightened by our crank guy.
Always check the rear flange after words and true it up.
 
I add weights to cranks all the time so I can weigh in here. I use cranks that have never been turned so, they are pricey and these are hard to find. I have my weights lazer cut with 2 being 4.010 inside diameter and 2 being 4.110. This makes the fitting easier because the cheeks are different. I drill the weight in the center from top to the inside diameter 5/16 and countersink the hole 1/2" by 1/2" for the grade 8 socket head cap screw. I drill the crank 1" at 90 degrees to the throw as exactly as possible and tap the hole. Once I bolt the weight to the crank, I check to make sure it is parallel to the cheek. I carry the crank to the table and wrap all the journals and weld the weights on each end and weld the bolt hole shut. I then put the crank in the lathe and turn all 4 of the weights to the same size and champher the edges. I then take the crank to the grinder to be checked for straight and be re-ground to .010 undersize. If the crank is not straight, the grinder has the capacity to straighten it before grinding.

Just to answer the original question, I have 5 or 6 cranks on the shelf that are fresh ground but, needing 2 counterweighted cranks, I pulled 2 cores out and am now waiting for them to come back from the grinder. I agree with the general consensus that, weighted cranks should be re-ground after adding the weights.
 
Tom at the Model A Ford Works has had a number of cranks done with the weld on counter weights. They are in running cars. A good welder knows how to spread the welds out across the whole job to keep any warping to a minimum. If you weld one counter weight on at a time, yes you will get warping.
 
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