426 Max Wedge questions

[s/w theo]

A friend of mine has a mechanic friend who bought a 426 Max Wedge engine & is not too familiar with older Mopars, (It is 2-1/2 hours away from me, otherwise I would love to see it, & it's believed to be real. Dual quad cross ram, Max Wedge exhaust manifolds etc.) & having a vibration problem above idle. I think they are using an (used) externally balanced flywheel on it, causing the vibration. First question, aren't ALL Max Wedge engines internally balanced? It came with the auto. trans. which leads to my second question, were ALL the crankshafts drilled for the manual trans? (My friend said they had to have the flywheel milled to fit the crank register of the torque converter) Third question, if it is internally balanced, shouldn't it have a NEUTRAL balance damper & flywheel (When swapping over to a manual trans.) Since I can't see the engine myself & not being too Max Wedge savvy, what should they look for to see if it's a real Max Wedge?
Thanks in advance.

 

[AR67GTX]

I don’t know a lot but I’m pretty sure the max wedge motors were internally balanced like any other 413, 426, or 440.

Im confused by this quote - “(My friend said they had to have the flywheel milled to fit the crank register of the torque converter)”. Did you mean flex plate instead of fly wheel? I understand some cranks for auto transmission cars were not fully machined for a manual transmission pilot bushing - but I’m not sure which ones or what years.

 

[s/w theo]

I don’t know a lot but I’m pretty sure the max wedge motors were internally balanced like any other 413, 426, or 440.

Im confused by this quote - “(My friend said they had to have the flywheel milled to fit the crank register of the torque converter)”. Did you mean flex plate instead of fly wheel? I understand some cranks for auto transmission cars were not fully machined for a manual transmission pilot bushing - but I’m not sure which ones or what years.

My friend said that they had to mill, what I'm guessing, is the back part of the FLYWHEEL to fit the hole in the crankshaft where the torque converter snout fit. They are swapping it over to a 4-speed manual. There were big block Chrysler engines that were externally balanced from the factory that used a weighted harmonic balancer, flywheel or flex plate if an automatic, I think.
The Max Wedge engines were a pure racing engine, so I would imagine they were all internally balanced.

 

[Dave6T4]

Max Wedge engines were all internally balanced. External balance on a big block did not happen until the early '70's. A real Max Wedge block would have "MP" stamped on the pad near the distributor clamp. The block should also have "AAQA" cast into it, denoting a high nickel content casting.

 

[Dave6T4]

In my experience, the manual transmission flywheel and automatic transmission drive plate are interchangeable on big blocks, with no additional machining required. Something does not sound right there.

 

[s/w theo]

In my experience, the manual transmission flywheel and automatic transmission drive plate are interchangeable on big blocks, with no additional machining required. Something does not sound right there.

My feelings exactly. I wish I could see it in person to get a better idea of the problem. I will give the info to my buddy to pass on. Thanks

 

[Lefty71]

Something does not sound right there.

Indeed.... I can't imagine why someone would throw the wrong balancer on, for no reason. Maybe the OPs friend can get some pix..... anything with numbers or stampings will help us figure this one out. Pic of the head casting number (under the valve covers) would be a huge help. Best of luck.

Also, I wouldn't run it, til this is sorted.

 

[RemCharger]

Sadly there is no way of knowing what crank is in there without pulling the pan, that I'm aware of anyway.

 

[Rebelrouser]

Indeed.... I can't imagine why someone would throw the wrong balancer on, for no reason. Maybe the OPs friend can get some pix..... anything with numbers or stampings will help us figure this one out. Pic of the head casting number (under the valve covers) would be a huge help. Best of luck.

Also, I wouldn't run it, til this is sorted.

To my knowledge all max wedges are internally balanced. The register for the flywheel is also the same to my knowledge. As far as the cranks being drilled for pilot bushing, they all have a hole, but some are not finished machined. I usually just take a stock pilot bushing and chuck it in the lathe and turn it to fit the hole. Somebody used to sell the thinner bushings, but I forgot who did. A picture of the balance would tell if it is the right one, it should be flat all the way across, the weighted balancers had a lump on them. This is what a 440 six pack balancer looks like

 

[s/w theo]

Thanks for all the replies. I will relay all this info to my friend today so he can tell the owner of the Max Wedge engine. I'm pretty sure he won't run the engine until he fixes his vibration problems, & now he has a definite place to start looking. I wish I could put eyes on it myself, but it's too far away & I don't plan on going up to that area until later next month.

 

[33 IMP]

If he had to machine a flywheel to fit, he's got the WRONG flywheel. And yes, ALL maxwedges were steel crank, internally balanced.
But as suggested above, a 60 year old engine might have ANY crank in it.
Pics are a real 426 max.

 

[AR67GTX]

My friend said that they had to mill, what I'm guessing, is the back part of the FLYWHEEL to fit the hole in the crankshaft where the torque converter snout fit. They are swapping it over to a 4-speed manual. There were big block Chrysler engines that were externally balanced from the factory that used a weighted harmonic balancer, flywheel or flex plate if an automatic, I think.
The Max Wedge engines were a pure racing engine, so I would imagine they were all internally balanced.

Yeah, I forgot about the externally balanced cast cranks in the 70s. Good reminder. But I understand what you are saying about having to mill the flywheel to fit on the crank now - sounds strange, just no clue as to why? Good luck.

 

[s/w theo]

I just now passed on the info everyone gave me on these engines. Thanks to all, for your help on this. I will let you know how & when it gets straightened out.

 

[IT'S DYNAMITE]

A friend of mine has a mechanic friend who bought a 426 Max Wedge engine & is not too familiar with older Mopars, (It is 2-1/2 hours away from me, otherwise I would love to see it, & it's believed to be real. Dual quad cross ram, Max Wedge exhaust manifolds etc.) & having a vibration problem above idle. I think they are using an (used) externally balanced flywheel on it, causing the vibration. First question, aren't ALL Max Wedge engines internally balanced? It came with the auto. trans. which leads to my second question, were ALL the crankshafts drilled for the manual trans? (My friend said they had to have the flywheel milled to fit the crank register of the torque converter) Third question, if it is internally balanced, shouldn't it have a NEUTRAL balance damper & flywheel (When swapping over to a manual trans.) Since I can't see the engine myself & not being too Max Wedge savvy, what should they look for to see if it's a real Max Wedge?
Thanks in advance.

There is no difference on the flywheel hub mount on any of the 361 to 440 crabks. The heni is an 8 bolt crank but still the same hub size.
Maybe there was a problem with the engine at one time and the crank was replaced with a 440 cast crank. that will set up a vibration if it does not have the right damper. The damper in the picture is for a 440 cast crank. When I balance on my Hines 550 digital balancer all the flywheels are done to a "zero",so that the flywheel if it ever had to be replaced would not change the smoothness of the engine. I have also had to redrill the back of the crank in order to install the pilot as Chrysler use to have 2 different part # for manual or automatic transmissions until the smartened up and started making only one crank which had the pilot bushing hole.

 

[s/w theo]

There is no difference on the flywheel hub mount on any of the 361 to 440 crabks. The heni is an 8 bolt crank but still the same hub size.
Maybe there was a problem with the engine at one time and the crank was replaced with a 440 cast crank. that will set up a vibration if it does not have the right damper. The damper in the picture is for a 440 cast crank. When I balance on my Hines 550 digital balancer all the flywheels are done to a "zero",so that the flywheel if it ever had to be replaced would not change the smoothness of the engine. I have also had to redrill the back of the crank in order to install the pilot as Chrysler use to have 2 different part # for manual or automatic transmissions until the smartened up and started making only one crank which had the pilot bushing hole.

Thanks for the info. I will pass it along also.

 

[Dipstick]

Over the years, the factory used different ways to externally balance a flywheel. Sometimes is was a drilled hole or holes and sometimes it was a scalloped cut with a milling cutter. It's often hard to tell the the external balance holes from the mass balance holes, so a used flywheel of unknown origin is always iffy balance wise.

 

[s/w theo]

Over the years, the factory used different ways to externally balance a flywheel. Sometimes is was a drilled hole or holes and sometimes it was a scalloped cut with a milling cutter. It's often hard to tell the the external balance holes from the mass balance holes, so a used flywheel of unknown origin is always iffy balance wise.

Thanks. Got all the info I needed.