[robbyoj007]

Good night fellow Honda enthusiasts. I have two B15 engens. But Just today I am realizing that one of them has a larger crankshaft than the other. By the way, the one with the smaller crankshaft the keyway is damaged so I wanted to change it, only to realize the difference. The mechanic says that the larger crankshaft is a better engine.
Questions:
1. Is it ok to use welding to repair the keyway?
2. What is the correct series for the engine with the larger shaft? and
3. Are the cylinder heads be swapped around?

 

[mattliston]

You are likely referring to the crank snout.

Measure them. One will likely be 24mm at the base of the pulley location, the other should be 22mm, if memory serves me well.

you can carefully weld up the keyway, and re-cut. This will take someone with a bit of skill, measuring the degrees angle, and making sure you do not overcut it.

If you simply use the other crankshaft, just grab a matching crank pulley. Once you measure the snouth size, we can help track down a replacement.

 

[robbyoj007]

The snout is 28mm. I am still trying to find a pulley in my neck of the woods. No success as yet. I should be able to repair the other one I guess I will do that and keep that bottom half as a spare.

 

[drtalon123]

No one around me will quick job repair these crank snouts, and for the following reasons.

If you do weld the snout, you MUST grind off the outer case nitride layer first.

All Honda cranks are nitrided, and have a very thin hard layer about 0.001-0.004" built up on the surface.

If you dont cut the nitride layer off before welding, it will contaminate your weld. It will be very difficult to TIG weld if you dont get all the nitride away from the area to be welded.

The heat from welding may also compromise the structural forging of the snout parent metal. The keyways and balancers on these cranks are barely on the snout itself, hanging like 1/2" off the end of the snout, which is ridiculous in the first place, but Honda got away with that because of how good their forging process actually is. When you weld and add heat, the forged properties begin to disappear, and weird stresses between the snout and the rest of the crank could appear.

For these reasons, no crankshaft shop or machine shop near me will touch welding Honda cranks without also opting to get them re-heat treated, re-nitrided and re-machined. And I dont blame them, their name is on their doors, and they arent going to tarnish their names for a quick "might fix it" on some honda boy's crank lol.


Because of this, I opted to fix a crankshaft keyway that @Oldcivicjoe donated to me by using carbides to cut a notch out of the crank, then fill in the space with a piece of keyway stock from a hardware store, then using some Loctite 660 to fill the gaps.

I then shaped the little piece of metal with a grinder and a file to follow the profile of the crankshaft curve as well as build a new wall for the balancer key. The balancer slipped right on, and the keyway fit perfect.

 

[robbyoj007]

No one around me will quick job repair these crank snouts, and for the following reasons.

If you do weld the snout, you MUST grind off the outer case nitride layer first.

All Honda cranks are nitrided, and have a very thin hard layer about 0.001-0.004" built up on the surface.

If you dont cut the nitride layer off before welding, it will contaminate your weld. It will be very difficult to TIG weld if you dont get all the nitride away from the area to be welded.

The heat from welding may also compromise the structural forging of the snout parent metal. The keyways and balancers on these cranks are barely on the snout itself, hanging like 1/2" off the end of the snout, which is ridiculous in the first place, but Honda got away with that because of how good their forging process actually is. When you weld and add heat, the forged properties begin to disappear, and weird stresses between the snout and the rest of the crank could appear.

For these reasons, no crankshaft shop or machine shop near me will touch welding Honda cranks without also opting to get them re-heat treated, re-nitrided and re-machined. And I dont blame them, their name is on their doors, and they arent going to tarnish their names for a quick "might fix it" on some honda boy's crank lol.


Because of this, I opted to fix a crankshaft keyway that @Oldcivicjoe donated to me by using carbides to cut a notch out of the crank, then fill in the space with a piece of keyway stock from a hardware store, then using some Loctite 660 to fill the gaps.

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I then shaped the little piece of metal with a grinder and a file to follow the profile of the crankshaft curve as well as build a new wall for the balancer key. The balancer slipped right on, and the keyway fit perfect.

I will not ask if it works. What I will ask is if it last and for how long? Form experience I know that the weld would compromise the structure of the steel, but I was hoping that someone would have done it before. I think that the length of the snout is just too short. Thanks again I do appreciate your comment.

You are likely referring to the crank snout.

Measure them. One will likely be 24mm at the base of the pulley location, the other should be 22mm, if memory serves me well.

you can carefully weld up the keyway, and re-cut. This will take someone with a bit of skill, measuring the degrees angle, and making sure you do not overcut it.

If you simply use the other crankshaft, just grab a matching crank pulley. Once you measure the snouth size, we can help track down a replacement.

Thanks for the link for the manual

 

[drtalon123]

What I will ask is if it last and for how long?

As long as the balancer is good, and you're not running the engine to redline constantly, it will probably last a while. Can't really say for how long!

Hopefully others have tried to weld their cranks can comment!

What I can say is that if you try doing the extra piece of keyway like I did in the pictures, that fix worked for me. I abused the snot out of my engine for almost 2 years before taking it apart for a rebuild, and the keyway fix and snout were fine. I plan to use it again after the rebuild.

 

[robbyoj007]