318 std piston quench with aluminum heads?

[340inabbody]

I understand that the balance of the 318 and 340 rotating assemblies are not the same. @Illahe are you saying this is a 318 forged crank? I can only assume this rotating assembly was balanced to accommodate the change in piston weights (FORGED TRW’s) but maybe not?

So far I verified that my harmonic balancer is neutral balanced! I am in the process to see if I can verify if the torque converter has any weights welded to the front face. So far I didn’t see any.

So this is concerning because my assumption that the rotating assembly may not be balanced and this might be the cause of the vibration?????????????

Comments?

 

[Zigtf216]

I had to go look, forged stock cranks have square corners on the tops of counterweight, cast cranks are rounded off. You have what appears to me a cast crank. That wouldn’t bother me as much as the rod bolts and nuts. Good luck with those, the one castle nut is probably the only one that will come off without galling up the threads on the bolt. If you have the proper harmonic balancer and proper counterweight on the converter you are still screwed unless the assembly was balanced to your aftermarket pistons. You can internally balance cast crankshafts then use neutral balancer and converter. My machinist internally balances magnum crankshafts and feels safe with them to 500 hp. We ran cast crankshaft in a circle track truck and turned that thing 7000 rpm with no problems. Sold the engine to a truck puller, he turned it 8000. Didn’t last long doing that!

 

[Newbomb Turk]

I had to go look, forged stock cranks have square corners on the tops of counterweight, cast cranks are rounded off. You have what appears to me a cast crank. That wouldn’t bother me as much as the rod bolts and nuts. Good luck with those, the one castle nut is probably the only one that will come off without galling up the threads on the bolt. If you have the proper harmonic balancer and proper counterweight on the converter you are still screwed unless the assembly was balanced to your aftermarket pistons. You can internally balance cast crankshafts then use neutral balancer and converter. My machinist internally balances magnum crankshafts and feels safe with them to 500 hp. We ran cast crankshaft in a circle track truck and turned that thing 7000 rpm with no problems. Sold the engine to a truck puller, he turned it 8000. Didn’t last long doing that!

Look at the pictures very close. In one of them you can see a wide parting line.

It’s a steel crank.

 

[Illahe]

I understand that the balance of the 318 and 340 rotating assemblies are not the same. @Illahe are you saying this is a 318 forged crank? I can only assume this rotating assembly was balanced to accommodate the change in piston weights (FORGED TRW’s) but maybe not?

So far I verified that my harmonic balancer is neutral balanced! I am in the process to see if I can verify if the torque converter has any weights welded to the front face. So far I didn’t see any.

So this is concerning because my assumption that the rotating assembly may not be balanced and this might be the cause of the vibration?????????????

I understand that the balance of the 318 and 340 rotating assemblies are not the same. @Illahe are you saying this is a 318 forged crank? I can only assume this rotating assembly was balanced to accommodate the change in piston weights (FORGED TRW’s) but maybe not?

So far I verified that my harmonic balancer is neutral balanced! I am in the process to see if I can verify if the torque converter has any weights welded to the front face. So far I didn’t see any.

So this is concerning because my assumption that the rotating assembly may not be balanced and this might be the cause of the vibration?????????????

Comments?

I understand that the balance of the 318 and 340 rotating assemblies are not the same. @Illahe are you saying this is a 318 forged crank? I can only assume this rotating assembly was balanced to accommodate the change in piston weights (FORGED TRW’s) but maybe not?

So far I verified that my harmonic balancer is neutral balanced! I am in the process to see if I can verify if the torque converter has any weights welded to the front face. So far I didn’t see any.

So this is concerning because my assumption that the rotating assembly may not be balanced and this might be the cause of the vibration?????????????

Comments?

Attached are two photos of a forged 273 crank, 3.31 stroke. The second two photos are a 318 cast 3.31 stroke crankshaft.

In post 73 I referenced the information from FABO that mentions that the 340 rod throws are drilled on 1/2 and 7/8 rod throw. Considering the TRW pistons are in the weight class of a battleship, I'm curious as to how the machine shop got the balance light enough with a solid rod throw.

Obviously, someone has matched the weights of your connecting rods. You claim there is a vibration at a specific RPM. If it was my short-block, I would take your photos to a machine shop including photos of the counterweights and ask a competent machinist how he would balance that rotating assemble, and if he saw any discrepancies.

Once again, I'm referencing material from FABO, and cant find a lot of information that defines the many forged 3.31 stroke crankshafts that were produced for OEM applications.

Personally, I'm not convinced that the rod throw weight is the same for all forged units produced at the factory.

 

[Zigtf216]

I have the same thing, on the right is a 73 3.31 cast crank notice the rounded counterweights, in the middle is a 1970 forged 3.31 crank notice the square edge counterweights and a parting line. The op has rounded counterweights. The left is aftermarket 4” forged

 

[Illahe]

I have the same thing, on the right is a 73 3.31 cast crank notice the rounded counterweights, in the middle is a 1970 forged 3.31 crank notice the square edge counterweights and a parting line. The op has rounded counterweights. The left is aftermarket 4” forgedView attachment 1716495201

The crankshaft on the far right is forged. The center crankshaft is cast and the crank on the left looks like an aftermarket cast.

 

[toolmanmike]

The crankshaft on the far right is forged. The center crankshaft is cast and the crank on the left looks like an aftermarket cast.

Yep. Rounded counterweights tell the story as well as the wide parting lines. Tap it with a steel hammer. Forged will ring. Cast is more of a dull ring noise.

 

[Zigtf216]

Please excuse my dyslexia and poor memory. I have my head out of my *** now!

 

[340inabbody]

Ok I have now confirmed that the torque converter has no observable weights nor does the harmonic balancer.

This supports the idea that the motor “should” have been internally balanced. But no way I can confirm this by looking at.

The vibration is not at a single resonance but starts at 2700 rpm or so and gets more noticeable as it increases. Not a massive vibration but detectable.

Twist while examining the oil pan I noticed a woodruff key lying in the pan. The key is 3/4 long indicating possible key from the cam that must have gotten loose and fell back down?

Maybe this is the cause of my issues? If the timing gear is slipping that would wreak havoc on everything. I now have to get in there and verify this is the missing key and replace it.

Not sure I can identify if this rotating mass is balanced but maybe I can talk to the machine shop as suggested above and show the pictures??

Open to any other suggestions.

Thank you for the help and advice guys.

Ron

 

[Illahe]

Ok I have now confirmed that the torque converter has no observable weights nor does the harmonic balancer.

This supports the idea that the motor “should” have been internally balanced. But no way I can confirm this by looking at.

The vibration is not at a single resonance but starts at 2700 rpm or so and gets more noticeable as it increases. Not a massive vibration but detectable.

Twist while examining the oil pan I noticed a woodruff key lying in the pan. The key is 3/4 long indicating possible key from the cam that must have gotten loose and fell back down?

Maybe this is the cause of my issues? If the timing gear is slipping that would wreak havoc on everything. I now have to get in there and verify this is the missing key and replace it.

Not sure I can identify if this rotating mass is balanced but maybe I can talk to the machine shop as suggested above and show the pictures??

Open to any other suggestions.

Thank you for the help and advice guys.

Ron

View attachment 1716495238

View attachment 1716495239

 

[Illahe]

A) Have you rotated the crankshaft and looked at the converter "face" 360 degrees to confirm there are no weights?

B) The woodruff key in the oil pan is definitely a (-) like the single castle nut on the rod cap. Yet, It's highly unlikely that your engine is spinning the camshaft in phase with just 35# of torque against the fuel pump eccentric.

C) A competent machine shop should be able to identify under/over balance by your vibration description.

D) Speculation (?) the engine builder was using a previously balanced set of rods and the matching crankshaft, then found an "E-bay" special on some 30 year old slugs and slapped the short block together.

E) There are no "free lunches" when your building a performance engine correctly; and none of us can diagnose the issues with your combination without scientific information. Bob weights, rotating mass, and the harmonics of your specific combination.

F) Are you swinging a "dead hole"? What do the plugs look like?

 

[junkyardhero]

the woodruff key in the pan, the castle nut on the con rod, some of the rod bolts show several threads past the nut, others show a scant few, a 73 with a forged crank, the washers on the oil pump bolts, the hodge-podge bolts on the flex plate, the clipped pan gaskets indicate that the front cover was off at some point.

i'd have that motor out and on a stand at this point. even if the vibration was something not rotating assembly/engine related, all of that work looks sus to me. just sloppy all around.

 

[Illahe]

the woodruff key in the pan, the castle nut on the con rod, some of the rod bolts show several threads past the nut, others show a scant few, a 73 with a forged crank, the washers on the oil pump bolts, the hodge-podge bolts on the flex plate, the clipped pan gaskets indicate that the front cover was off at some point.

i'd have that motor out and on a stand at this point. even if the vibration was something not rotating assembly/engine related, all of that work looks sus to me. just sloppy all around.

This: "i'd have that motor out and on a stand at this point." Gaskets are cheap...

In theory, he may be able to undue the sketchy sh** and make a decent runner out of the long block...

 

[340inabbody]

A) Have you rotated the crankshaft and looked at the converter "face" 360 degrees to confirm there are no weights?

B) The woodruff key in the oil pan is definitely a (-) like the single castle nut on the rod cap. Yet, It's highly unlikely that your engine is spinning the camshaft in phase with just 35# of torque against the fuel pump eccentric.

C) A competent machine shop should be able to identify under/over balance by your vibration description.

D) Speculation (?) the engine builder was using a previously balanced set of rods and the matching crankshaft, then found an "E-bay" special on some 30 year old slugs and slapped the short block together.

E) There are no "free lunches" when your building a performance engine correctly; and non of us can diagnose the issues with your combination without scientific information. Bob weights, rotating mass, and the harmonics of your specific combination.

F) Are you swinging a "dead hole"? What do the plugs look like?

A. Yes I have a remote starter rotating it. I just took that one shot since I can’t post a video of the whole face rotating.

B. Your saying the camshaft woodruff key loss probably isn’t a problem due to the compression force on the cam preventing slippage?

C. From the pictures?

F. Whay do you ask? All plugs look ok say for #7 which looks richer than the others.

 

[340inabbody]

This: "i'd have that motor out and on a stand at this point." Gaskets are cheap...

In theory, he may be able to undue the sketchy sh** and make a decent runner out of the long block...

Thanks I am getting to this point my 2 fused discs and cervical stenosis and general degeneration is maxed out from working on my back. I am getting too old for this stuff no matter how much I want to learn and do.

I was thinking of fixing this but if the loss of the woodruff key isn’t causing the vib and I can’t confirm any balancing then I guess it’s time for it to come out.

 

[Illahe]

Thanks I am getting to this point my 2 fused discs and cervical stenosis and general degeneration is maxed out from working on my back. I am getting too old for this stuff no matter how much I want to learn and do.

I was thinking of fixing this but if the loss of the woodruff key isn’t causing the vib and I can’t confirm any balancing then I guess it’s time for it to come out.

Be patient. Nothing is “smoked” so you can go through your set up, get the balance straightened out. Fix the sketchy hardware and then you’re confident the short-block will live.

With those 12:1 you should have a decent SFT cam in the 340 to get the most out of its potential. Standard volume oil pump is fine, but install the M.P. High pressure spring.

In the end, that engine should shift between 65-6700 all day.

Get a good Chrysler performance engine rebuild manual.

Note: The oil pump looks like a Chinese knock off of Melling 72.

 

[Illahe]

A. Yes I have a remote starter rotating it. I just took that one shot since I can’t post a video of the whole face rotating.

B. Your saying the camshaft woodruff key loss probably isn’t a problem due to the compression force on the cam preventing slippage?

C. From the pictures?

F. Whay do you ask? All plugs look ok say for #7 which looks richer than the others.

View attachment 1716495244

The cam wold likely lose phasing without a woodruff key. #7 looks like the cylinder is ill. Compression/leak-down(?). It’s still together!

 

[mygasser]

you did of course make sure there's nothing engine/trans wise touching the body etc didn't you? it doesn't take much to vibrate like you describe.
neil.

 

[junkyardhero]

This: "i'd have that motor out and on a stand at this point." Gaskets are cheap...

In theory, he may be able to undue the sketchy sh** and make a decent runner out of the long block...

agree. the bones are there.

a whirlwind tour at the machine shop, some gaskets and you could be back to business.

[with new rod bolts for peace of mind]

i don't think there's anything that's fundamentally wrong, it just all looks so... sloppy... which brings into question *waves hands* all this

to me, when you can't do the basic **** right (flex plate bolts) it makes me cast a hairy eyeball upon everything else.

 

[340inabbody]

you did of course make sure there's nothing engine/trans wise touching the body etc didn't you? it doesn't take much to vibrate like you describe.
neil.

I believe so. I have inspected it. I noticed that the trans was missing the two mounting bolts and I installed them. No change.

 

[340inabbody]

If I were to take it to a machine shop is there really anything they could do to confirm the rotating assembly is balanced? Ie without pulling the crank assy and putting it on a ballancer?

 

[Illahe]

If I were to take it to a machine shop is there really anything they could do to confirm the rotating assembly is balanced? Ie without pulling the crank assy and putting it on a ballancer?

Not that I’m aware of. That engine has been balanced at one time. You just don’t know if it’s balanced to your piston and rod weights.

 

[340inabbody]

Not that I’m aware of. That engine has been balanced at one time. You just don’t know if it’s balanced to your piston and rod weights.

Lol isn’t that balancing?

 

[Illahe]

Lol isn’t that balancing?

Every balance is piston/rod weight specific.
There is no “balanced across the board.”

So, IE it “was balanced” at one time. If the piston weight changed “it’s out of balance now.”

 

[Illahe]

Lol isn’t that balancing?