[Dr. Zo]

All of those wear parts should be replaced.

Test your alternator rotor for looseness-

View: https://www.youtube.com/watch?v=Nqq_gS_i1yc


Find a good welder and have them weld up that crack, or you can clean it VERY thoroughly, dress it with medium emery paper, clean it again with denatured alcohol, then apply JB Weld clear epoxy and let cure.

The AAU is still re-usable, as long as the springs have good tension and the parts are not sloppy loose.

Sure enough, the spring is gone from the seal.

Thanks for the info on the rotor. I'll check but would probably feel better replacing it either way. The "AAU" is what - sorry!

 

[Dr. Zo]

Too late now, but I would have left the cams and pinions in place and checked for runout, then NOT TOUCHED them unless it was excessive, checked against allowable spec.

That is one of two fork rollers that go on the little pins of the fork; they ride in the gearchange camplate slots.

OK, I'm not familiar with what "runout" is in this case. Is this something then that will have to be accomplished on assembly or is there some other way? On the fork roller, yes, I see now. Since this was the last thing I took off I can see why I wasn't sure of its origin.

 

[Dr. Zo]

I got the cases split today. I still have some challenges ahead. First off it was difficult getting the cases apart, I had to heat them a bit before I got some movement. There seems to be an awful lot of gasket cement and other goo on all the joints.

So, the intake cam is not original. I’m wondering if any forum members might be familiar with this brand - Megacycle Cams from California?

I wasn’t able to get the rods off the crank. These say “JRC” and have 6 point star bolts. I got one loose but the other won’t budge with a long breaker. Any advice on how to get these off - many thanks! Do I finally need to get an impact driver?? Plus - any knowledge of these rods? They are obviously not original and I imagine I need to determine if they are still OK to use in the rebuild. I’ve got to get them off first. And one more thing - these do not have bushings in the small end so not sure how to manage that when I build it back.

I could not remove the exhaust cam because I can’t get the key out of the end. It looks almost like whoever assembled the beast deformed the top of the key a bit. I’ve tried picks and such to get it out. Any ideas on how to remove this so I can take a look at the cam?

I’m curious why someone would have filled in the hole with some compound (silicone?) on the end of the smaller transmission shaft?

One end of the crank is buggered a bit from some PO. Not sure if this is still ok for the rebuild. Notice the bearing is still on the crank. I’m wondering what kind of puller is needed to get this off the crank?

There is a number engraved on the flywheel of the crank - #10595 - any idea of what this is for? I am impressed by the weight of the flywheel!

So, I’ve got to get the rods off, bearing off the crank, then I should find someone close by to do some hydro-blasting.

Thanks for any comments or advice!!

 

[GrandPaulZ]

Thanks for the info on the rotor. I'll check but would probably feel better replacing it either way. The "AAU" is what - sorry!

AAU = Auto Advance Unit (flyweights with springs that advance the points cam)

To check runout, place a dial indicator pointer on the cam at the base circle (lowest spot) and try to wiggle the cam up and down. The shop manual indicates allowable play.

If one cam is Megacycle, they are probably BOTH Megacycle. Stuart gave you good advice on TTalk re: con rods.

Looks like you have a somewhat hot-rodded engine; the crank has been balanced, but will only be correct if the same rods and same weight pistons are used / re-used. Even the sump plug will be significant (weight-wise). If you replace it, the replacement plug should be the same weight to within a gram or less if possible.

 

[Dr. Zo]

AAU = Auto Advance Unit (flyweights with springs that advance the points cam)

To check runout, place a dial indicator pointer on the cam at the base circle (lowest spot) and try to wiggle the cam up and down. The shop manual indicates allowable play.

If one cam is Megacycle, they are probably BOTH Megacycle. Stuart gave you good advice on TTalk re: con rods.

Looks like you have a somewhat hot-rodded engine; the crank has been balanced, but will only be correct if the same rods and same weight pistons are used / re-used. Even the sump plug will be significant (weight-wise). If you replace it, the replacement plug should be the same weight to within a gram or less if possible.

OK, thanks for this. The PO did talk about the engine being heated a bit. Assuming I am able to use the same rods, the old pistons need replacing. Would/Should I try to find pistons close to the old piston's weight, and then have them shaved somewhere to equal the old piston's weight? Or?

 

[Dr. Zo]

OK, thanks for this. The PO did talk about the engine being heated a bit. Assuming I am able to use the same rods, the old pistons need replacing. Would/Should I try to find pistons close to the old piston's weight, and then have them shaved somewhere to equal the old piston's weight? Or?

It seems I remember in one of my manuals the crank being balanced sans rods and pistons. Perhaps I am not up on my physics here, but is this the way it is usually done - that is balancing the crank with the rods and pistons attached? I know I am out of my depth here.

 

[StuartMac]

Hi,

rotor, but was able to get a 3 jaw puller to get it off.

Test your alternator rotor for looseness-

As a poster in your thread in the other forum advised, consider replacing the rotor:-

. The "6 68" on the rotor indicates it was made in February (Week 6) 1968. Aiui, at that time, the individual magnets simply sit on the faces of the hex. steel centre, the (visible) caps sit on the magnets, everything's only held in place by the non-magnetic material cast around them.

. As you've used a puller to remove the rotor, you've strained the joint between the rotor's cast non-magnetic material and the steel centre. The joint might be fine when you check it but, if the joint ever fails, when the engine's accelerated and decelerated, the centre hex. acts like a wedge, pushing the magnets outwards, which pushes the caps outwards. There's only between 8 and 12 thou. between the rotor rotating at several thousand rpm and the stator not rotating at all ...

some difficulty getting the advance off as the interior threads would not take my puller. Looking closely it seems they have been damaged, so this should probably be replaced.

The AAU is still re-usable, as long as the springs have good tension

As your other thread says, just the thread on your puller was wrong? If you assumed the AAU was original to the '69 engine and threaded 5/16"-24 but it's actually older ('67?) and threaded 5/16"-26?

At best, the AAU is still over fifty years old and even still functioning perfectly (you wish), with points, it's still a crude way of delivering a timed spark. You've posted already you intend to fit a later alternator stator. Stator costs are pretty-much the same irrespective of output; so a so-called "high output" 3-phase (which is the same physical size as the one you took out)? Then, given the amount of money you're spending on your rebuild, a new rotor is minimal additional cost? Then, given electronic ignition specifically for these old heaps has been around for fifty years and will give more-accurate spark timing over a wider rpm range ...?

Hth.

Regards,

 

[StuartMac]

Hi Paul,

Stuart gave you good advice on TTalk re: con rods.

I wish but it was @speedrattle Kevin ...

Regards,

 

[GrandPaulZ]

It seems I remember in one of my manuals the crank being balanced sans rods and pistons. Perhaps I am not up on my physics here, but is this the way it is usually done - that is balancing the crank with the rods and pistons attached? I know I am out of my depth here.

Dynamic balance MOST LIKELY (no way to be sure, unless you can track down the etched number that was likely put there by the party that balanced the crank).

The balancer clamps the appropriate weights to the journals to represent the rods & pistons' weight, then the entire affair is balanced. Better than static balancing, and most likely was used when you consider all the other parts you have there.

If you have to re-bore, you'll need to replace anyway, and likely a re-balance would be in order unless you can SOMEHOW match larger pistons' weight to the existing pistons.

 

[Dr. Zo]

Dynamic balance MOST LIKELY (no way to be sure, unless you can track down the etched number that was likely put there by the party that balanced the crank).

The balancer clamps the appropriate weights to the journals to represent the rods & pistons' weight, then the entire affair is balanced. Better than static balancing, and most likely was used when you consider all the other parts you have there.

If you have to re-bore, you'll need to replace anyway, and likely a re-balance would be in order unless you can SOMEHOW match larger pistons' weight to the existing pistons.

OK, so this, like the head, is going to be best left to an expert. Once I've gotten it figured out what barrels I will use and then the appropriate pistons, etc, I should find someone who can dynamic balance this crank.

 

[Dr. Zo]

I was able to remove the rods with a longer breaker bar. I see there are no bushings in the small ends so this seems strange. I suppose it will be an issue when trying to fit new pistons. Also the big end bearings read: 70-3586. I appreciate comments on this reading!

I removed the valves and it looks like they will need replacing. I noticed that one of the guides is different from the rest - the right side exhaust guide. I see lots of gunk near the guides, perhaps from too much gasket cement? The valve ends do show some indentations on the bearing surface and I wonder if this is normal or excessive?

There was a question about the oil pump and the nuts used to secure it. The nuts securing this were lock nuts without washers.

I’m still waiting on a bearing puller to get the bearing off the crank.

Cleaning the gunk and oil off the cases is much more difficult than I imagined!

 

[speedrattle]

that odd valve guide was probably an oversize

 

[GrandPaulZ]

Rod bearings and crank journals look good. I'll bet they polish up to re-fit new original size shells.

Small ends do not take bushings.

 

[Dr. Zo]

Rod bearings and crank journals look good. I'll bet they polish up to re-fit new original size shells.

Small ends do not take bushings.

Rod bearings and crank journals look good. I'll bet they polish up to re-fit new original size shells.

Small ends do not take bushings.

OK, I did't know that about the small ends as I think I've seen some videos where the small ends were bushed. On the polishing, is this something I can do myself or is it a bit more complicated? Thanks

 

[GrandPaulZ]

OK, I did't know that about the small ends as I think I've seen some videos where the small ends were bushed. On the polishing, is this something I can do myself or is it a bit more complicated? Thanks

Unless you have precision measuring tools, I'd leave it to the machinist. The more work you give them ALL AT ONCE, the less each job will end up costing "onsie-twosie".

Yes, the small ends of the rods CAN be bushed, but rarely NEED to.

 

[Dr. Zo]

Unless you have precision measuring tools, I'd leave it to the machinist. The more work you give them ALL AT ONCE, the less each job will end up costing "onsie-twosie".

Yes, the small ends of the rods CAN be bushed, but rarely NEED to.

OK, got it!

 

[Dr. Zo]

Exhaust cam key frustration - So, I still haven't been able to remove the exhaust cam because I cannot get the key out from the right side, so it will slide out of the bushing. I even purchased a very small punch to try to move it a bit but it doesn't want to move easily. I also notice that this bushing has a cutout (see photo) that I have aligned with the key in the photo. The intake side bushing did not have this cutout - so I'm wondering if this is something that is supposed to be there? I hesitate to apply and more energy to the key/cam/bushing to get it out. Any ideas/comments on this difficulty are appreciated!

 

[speedrattle]

its not a cutout. its where the bushing was damaged by someone hammering the camwheel on instead of using the camwheel installation tool.

it looks like that key was firmly pounded in. this may be an opportunity to introduce yourself to a machinist.

 

[Dr. Zo]

its not a cutout. its where the bushing was damaged by someone hammering the camwheel on instead of using the camwheel installation tool.

it looks like that key was firmly pounded in. this may be an opportunity to introduce yourself to a machinist.

OK, too bad. I think whomever/PO/what-not, was a bit rough in their previous "rebuild." I've noticed a few anomalies as I've taken this apart. I wonder if a little heat applied might help? If this is damage to the bushing, I reckon this cam bushing, at least, will need to be replaced?

 

[speedrattle]

maybe not. if it just has the notch, cleaning it up with a needle file will probably do it. you dont want to take em out if you can help it because the new ones have to be hand fitted for length and endfloat and then reamed, which takes a special tool kit. i have found lately that new ones come pre-sized, which means too big to start with.

on the key, i would warm it with the torch and then persistently tap at it from as far underneath as you can get until it tips up and comes out.

it looks like that key has sheared, which might cause enough distortion to jam it in the slot. what does the keyway in the camwheel look like?