AMC 327 - 443 XRV8

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amcenthusiast
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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Fri Nov 17, 2017 11:26 am

Can't teach an old dog new tricks?

Whatever, I learned to do this the hard way; use cut sheets of flashing to protect the journals while making touch up welds on the crank.

Fastened on with wire ties, they won't fall off.

It doesn't hurt to use aluminum tape in less critical areas and cover the rest of the crankshaft with wet towels... they still might catch on fire so be ready (as any welder should always be ready with an assortment of fire extinguishing devices)

Anyway, this is how to protect the journals for touch up/detail welding work done on a crankshaft (use tie wire to secure wrapped on cut-to-fit steel flashing to protect the journals) neither will this way come loose or fall off while working on the crank while it's placed on a firepit for heat soak:
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XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Fri Nov 17, 2017 8:37 pm

With the first cuts made to get 4.082" stroke, Milo and I were both kinda proud the crank came out 'straight', with no need for any crank straightening work.

Evidently I became overconfident and decided to build up the first cheek between main bearing #1 and the first crankpin journal... without placing the crank on the pit...

After making several other small welding touch ups, I took it back to have the final cuts made.

Milo called and told me... it's not straight, and asked if he could go ahead and try to straighten it.

Of course I said 'yes'.

The next call, Milo tells me how he fixed it by welding up the crank snout and re-cutting all the mains .020"...I confessed and told him what I'd done... (built up the front cheek, not on the firepit)

So... there it is; for anyone else who'd like to know, it was another lesson learned: expect to distort the straightness if you weld on a cheek when it's not heat soaked on a firepit.

Milo said he was able to rebuild the crank snout on a conventional crank welding machine but to cut keyways he'd need to refer me to another shop.

I said thanks & I'd try to cut the keyways myself.
XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Fri Nov 17, 2017 8:52 pm

Milo said he tried using a press but it was so hard he couldn't budge it. Milo confessed 'when I was pushing on it to straighten it, it popped out of the press and landed on he floor. He said the loud 'bang' when it happened scared everyone nearby pretty bad!

Now all final cuts are made and the stroker crank is .020" on the mains and the rod journals are standard size (2.248") whew/scary... we made it though...
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XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Fri Nov 17, 2017 8:58 pm

At this point in the process I was under the mis-impression that I had a crank that was somewhere close to final balance... man was I ever wrong!

In reality, I had a lot to learn about balancing two plane V8 cranks!
XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Sat Nov 25, 2017 5:23 pm

Two pics, after crank pins cut to final size (std.) with 1/8" radius & more detail grinding to refine the shapes of the cheeks:
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XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Thu Dec 07, 2017 1:03 am

So at this point, having the journals cut to final size, I have something to take to a machine shop and have them run it on their balance machine.

I took where the crank grinder (Milo at E & E) told me to take it: Duffin Machine Shop in San Antonio Tx.

(Duffin was where Milo learned to grind welded up tractor pull cranks for one of the Duffin brothers)

(this might be a tip for anyone else 'out there' would might have welding skills and enough ambition to do their own custom welded crankshaft; contact 'tractor pull people'? They might know a local crank grinder in your area?)

So Duffin ran my crank on their Stewart Warner balancing machine. (what a beautiful sight that was for me to see my crank on a balancing machine!) He told me- 'Hey, this thing is way out of balance!/it almost jumped off the machine!" and pointed where he'd have to add mallory metal 'way over here' (off one side of the rear large counterweight) ...and said 'it smoothed it some by adding the damper on the front'. He made marks with a black sharpie on the big front and rear counterweights and told me how much weight I'd need to add in order to get internal balance... wow... about 620 grams on front and 640 grams on the rear... So paid him their fee to simply run it on the machine ($75) & took it back home to work on it some more.

Now what?

First thing of course is to look it up on the Internet; review every article online about adding mallory metal and look at other stroker cranks to see what 'the Pros' do. I spent hours on end looking up and reading every article I could find telling about crank balancing.

I found a few good articles on how not to install mallory metal; 1) you can't just push it into one of the pre-existing lightening holes and weld it in like that: the mallory metal does not weld well at all and it most likely will come out like a bullet (not good for the engine when that happens!) 2) The 'slug' (which is an appropriate term for weight by the way) needs to go into a hole drilled sideways through the counterweight... and it can't be too close to the edge (as tempting as that may be because the further out the weight is from the centerline of the crank, the more centrifugal force/effect it has) ...rather, the drilled hole to receive the 'slug' needs to be at least 1/4" in from the outer edge of the counterweight to 'hold it in' ...and it needs 'press fit' (I'd say about .0015" like a press fit wrist pin but get a second opinion) ...then a few welds won't hurt to keep it there for 'cheap insurance'.

In the course of looking up articles on how to balance a crankshaft, I found two articles on flywheel explosions.

Eg: One was showing pictures of a drag raced manual transmission 390 V8 AMX with rather large torn holes in the windshield cowling, just ahead of the lower edge of the windshield. They said it also took out part of the headers on the driver side but the owner/driver of the car was ok. The other article was a forum comment made by a guy who put a 'cheap' clutch on his drag raced AM 360 V8 powered Javelin; he said it tore a hole out of the back of the block (catastrophic damage) and had to replace the engine.

As a long term AMCer myself, I know both these engines came external balanced from the factory. I'm also familiar that most low buck engine builders don't re-balance their rebuilt engines... moreover people will swap externally balanced engine parts like a flexiplate or a harmonic balancer with little concern for finish balancing; like... if it came off another 360 its good to go on their 360 engine... like there is no more concern...

Then I found some really obscure original AMC information which told about 'replacement dampers and replacement flywheels' (for externally balanced '66-'91 AMV8 engines) That source said 'the factory replacement flywheel/flexiplates and harmonic balancers were made to have a 'middle weight' calculation which would serve both the heavier and the lighter balance variation on the factory built engines, but in ever case the factory recommended to keep the original flywheel and harmonic balancer on it's original engine if at all possible.

...to be continued.
XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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Re: AMC 327 - 443 XRV8

Post by amcenthusiast » Fri Dec 08, 2017 9:54 am

Here's a few pics I took of the crank prior to doing any balancing work.

The stock weight of the crank is perhaps most important, helping to defend against those who always say 'Rambler V8 is too heavy' (implying needless excess weight because the designers were ignorant)

The new weight of the 'welded up' crank is basically trivial, but surprising to notice I put at least three 5 lb. boxes of Lincoln welding rods on it but after basic grinding work it only weighed about 1.5 pounds more.

Rough guessing, considering 3/8" stroke was added to the stock journals, since one typically doesn't use the whole electrode when arc welding, but throws away 'the short' before they put on a new rod, this translates into about four pounds of added weld material for every 1/8" more stroke, then after grinding, about 1/2 pound more for every 1/8" added.
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XRV8 Race Parts > for AM's '56-'67 Rambler V8: http://amcramblermarlin.1colony.com/favorite_links.html

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