crank snout is UGLY

Beck · November 27, 2016, 11:23:38 PM

I finished pulling another of the 4 cylinder motors apart tonight. The crank is std/std but the crank snout is really ugly. It looks badly pitted all over. It is so bad that the balancer is loose on it. The timing gear was good and tight, but the snout was also pitted under it.

Are there repair sleeves made for the crank like the harmonic balancer?

Any idea what it cost to metalize something like this?

I could turn the front part of the snout down to SBC size (1.245). It is now SBF size (1.375).

Are bottom crank timing gears all the same OD and pitch? If so I could turn the snout down all the way to the bearing and use a SBC lower timing gear.

I would need to make a spacer to install into the front cover to mount a SBC crank seal.

I was hoping for a real nice .030" over bore in the block since I have 2 sets of those pistons. It didn't turn out as I wished. It was the right bore but has scoring. Taking it to .040" over would fix it but it would require custom pistons. .060" over pistons are readily available, but that is really to big for these blocks.

So it turned out I have some not so great parts. I don't know if they are worth messing with.

wayne petty · November 28, 2016, 12:11:44 AM

pictures.. you are really better off talking to a crank grinding shop that only does cranks.. they are likely to have a crank welder and carbon inserts to fill the keyways for welding up crank snouts then they can grind it back to size..

if the damper is loose.. you are in trouble.. or you will need like you say to turn it to the smaller size if you can get the proper insertion depth. .

you may only need to have the first inch welded.. even 3/4 inch of the snout.. you might get away without needing to machine the keyway.. could you machine a shoulder on the snout.. so you could put a centering ring on it.. that would be cheapest if you have the ability.. heck.. use a replacement valve seat.. should be able to get one really close to the proper OD..

do you have a valve seat insert catalog to look thru?? you can download the SBI complete valve, and valve seat catalog on this link.. http://www.sbintl.com/downloads.html

just ideas on the fly...

GPster · November 29, 2016, 09:48:17 AM

This is probably a stupid suggestion BUT. In the early '70s a friend of mine was running a "small block" Corvette in SCCA racing. His car was good enough to be going to Atlanta for the end of the season race and he was offered the chance to be a team car with a highly rated "name". The "name" not only wanted the car re-painted to the team's colors but was insisting on some motor changes. There was a cam change, change in headers and the motor was freshened up. The crankshaft was "Hard Chromed" at this time. We never talked about this problem we had when putting the car together. We had difficulty getting the transmission up to the bellhousing the last I/2" and when we started the engine we had trouble getting the transmission in gear without "crashing". I did not go to the race and the clutch/transmission problem rectified itself after it wore-in and problems were not talked about. In my mind after years have passed was the pilot bushing in the crank when it was "hard chromed" and the thickness of the procedure what gave us that problem? Would that procedure rectify your situation?. Do I not know anything and my suggestion is just daily entertainment. GPster

rumrumm · November 29, 2016, 12:14:56 PM

Fifteen years ago I had a harmonic balancer fail and it chewed up the crank snout on a sbc forged crank. The only fix other than a new crank was to take it to a crank shop, which I did. They welded it, turned it, and recut the keyway. Nice work. They saved a forged crankshaft and a lot of time and money associated with finding and preparing a different one.

Beck · December 01, 2016, 09:38:49 AM

I took the crank to a local metalizing shop today. They do really big parts, like RR car axles. The owner said they could do it but... They said most of their equipment was too big to handle the "little" crank. They also said that I wouldn't want them to do the job, since they have a $500 minimum.

He gave me 2 more places to check. One I have found has sold out and is no longer there. The 2nd is a little plating shop. He thought it could possibly be plated and then ground to size. I hope to get in contact with them today.

Beck · December 01, 2016, 09:47:54 AM

Quote from: "Beck"I hope to get in contact with them today.

I just called that shop. I knew the owner was elderly. He said the labor to mask a crank is too intensive for him. They aren't doing cranks any more. Strike 3.

chimp koose · December 01, 2016, 02:46:00 PM

How about trying to see if you can have it spray welded . The shaft is turned down to round , a light threading cut @ 80 TPI and then heated by torch and material sprayed on , then machined to size . Used to do that 30 yrs ago .

wayne petty · December 01, 2016, 09:06:11 PM

spray metalizing repair at ABOM shop..

with the casting number off the crank.. a call to some place like AA Midewest core supply.. might find you one with a good snout that needs grinding.

or just put it together and hold it tight with a stud and big nut instead of a bolt..

Beck · December 02, 2016, 07:36:29 PM

We have that exact spray weld torch at work that ABOM uses. We have a different brand of spray powder. The specks on our powder say it should work well. The equipment was last used over 20 years ago. No one there has ever used it. I am tempted to give it a try. We don't have any of the masking. Pricing on that isn't bad at about $22 plus shipping.

I really don't want to spray on our new lathe. There are a pair of woodruff keys in the snout. I don't know how to remachine those. I am not quite sure how I would chuck the flywheel end of the crank. I don't want to put the seal surface in the jaws. I would need to use brass or copper shims there I suppose. I would probably sacrifice a center since I have to spray up to the end of the shaft.

The other option is to knurl the snout.

wayne petty · December 02, 2016, 10:31:10 PM

you can spin the crank on almost anything.. wood lathe.. between two automotive hub and bearing assemblies..

the idea would be to drill a device to bolt tight to the end of the crank snout.. and center it on a lathe.. so you could reestablish the centers... make an insert for the pilot hole or rear crank flange to allow it to center on a live center..

since you are only doing a few inches if not just an inch of crank snout.. to keep the end of the damper centered..

there are carbon keyway inserts to prevent filling. or you could peal open a D cell battery and grab the core out of that and file or sand it to fit ..

chimp koose · December 03, 2016, 01:03:27 AM

Cover the ways with leather or heavy cloth . Put a lathe center in the chuck and tailstock . Use a long bolt through one of the bolt holes in the flange to be a drive dog off one of the lathe jaws . Yes fill in the woodruff keys with something and file them flush to the crank before spraying . This stuff is easy to peel off if you get under an edge so machine from the center of the build up out to the edges .You may also consider a product like belzona , a product similar to jb weld in application and completely machineable when cured . As I understand , it is used often in ship repair to propeller shafts

rumrumm · December 03, 2016, 11:37:54 AM

Call Abraham's Machine Shop in Davenport, Iowa. They repaired mine. They are 280 miles away from you which is do-able if you really want to save the crank.

Beck · January 07, 2017, 10:23:59 PM

I took the crank to a couple places trying to have the snout repaired. No one was interested because it is cast.

I was going to knurl the crank snout today. I hadn't paid a lot of attention to the rest of this crank. As I was cleaning it up I noticed something else. All of the rod journals have been welded up. There is porosity in the welds and small cracks. The cracking isn't only in the rod journals but the mains also. They may have had some welding too.

The casting is very rough. A couple of the local guys have looked at the crank and determined the problem with the snout was from an undersized rough casting. There wasn't enough metal to clean up in the machining process. I think the same was the case for the bearing areas. It's difficult to believe that MerCruiser would have done something like this. It wouldn't have been cost effective for the factory or a later rebuilder. What ever the reason, the crank isn't worthy of repairing for reuse.

The motor the crank came from was the worse than the others I have disassembled. I did run this motor briefly before disassembly. It didn't give any indication of it's internal condition. There was antifreeze in the pan when I purchased it, which isn't uncommon with it's water pump drive design.

If I had been the one welding it there would have been a bit more stroke added.

kb426 · January 08, 2017, 07:40:56 AM

Do you feel like the crank is worth using?

??

Beck · January 08, 2017, 12:02:26 PM

Quote from: "kb426"Do you feel like the crank is worth using? ??

As cheaply as I have been buying motors I think it would make more sense to trash this crank and hope for a good one in the next motor. I have been paying $100 for a motor. I know where there is a bigger hp version of this motor for sale for $200. The bigger hp doesn't help me because I am upgrading the cam and intake which gave it the extra power.