408C damper and flywheel question

408C damper and flywheel question

Joined: September 9th, 2010, 6:02 am

May 2nd, 2012, 6:07 am #1

Hello everyone,

I bought a rotating assembly from K1 technologies to bump my cubes up to 408 and had them balance it at the factory. A balanced rotating assembly from scat comes with a flywheel and damper. The kit from K1 did not. So now I have to buy a damper (the one of the original motor looks like Noah used it on his Ark somewhere) and possibly a flywheel... If I go down and grab a stock 351C flywheel, will it work on this engine, or will the engine not be balanced then? Same question for the damper.. Will it mess up balancing?

It is probably clear by now that I know nothing about engine balancing, or how its done, or what parts balance it. So confused... and disappointed that I'm now going to have to spend another $600 on a damper and flywheel.. Please help

Starting to feel pretty beaten down by this build...
Quote
Like
Share

Joined: May 20th, 2005, 4:48 pm

May 2nd, 2012, 12:02 pm #2

I assume that K1 internally balanced your rotating assembly. If that's true, then you will need a 0 balance flywheel and a 0 balance balancer. A stock 351C balancer/flywheel are imbalanced, so it won't work. Is there any documentation that you have which shows which way the rotating assembly was balanced?

And here's the "other thing..."

I don't know of any K1 forged crank that is setup for a Cleveland. By that, I mean that their cranks that I have seen are made for a 6.200" rod and the counterweights are larger for that reason. A 6.200" rod makes for an extremely short piston in a Cleveland (read 1" compression height). With that being said, which rod length did they use? If they used a 6" rod, I would do a quick mock-up and make sure that the pistons won't hit the counterweights at BDC.



Brent Lykins
B2 Motorsports, LLC






Quote
Like
Share

Joined: February 17th, 2004, 11:02 pm

May 2nd, 2012, 4:28 pm #3

Hello everyone,

I bought a rotating assembly from K1 technologies to bump my cubes up to 408 and had them balance it at the factory. A balanced rotating assembly from scat comes with a flywheel and damper. The kit from K1 did not. So now I have to buy a damper (the one of the original motor looks like Noah used it on his Ark somewhere) and possibly a flywheel... If I go down and grab a stock 351C flywheel, will it work on this engine, or will the engine not be balanced then? Same question for the damper.. Will it mess up balancing?

It is probably clear by now that I know nothing about engine balancing, or how its done, or what parts balance it. So confused... and disappointed that I'm now going to have to spend another $600 on a damper and flywheel.. Please help

Starting to feel pretty beaten down by this build...
> I bought a rotating assembly from K1 technologies to bump my cubes up to 408
> and had them balance it at the factory.

Did you buy this directly from K1 (or perhaps from a vendor who supplied the
pistons to go along with the K1 crank and rods)? I wasn't aware that K1 did
a complete kit for Cleveland engines and don't see anything listed in their
current catalog. Do the pistons have valve reliefs for canted valve heads or
inline?

> Will it mess up balancing?

I spoke with Tom Molnar of K1 about their Cleveland cranks. This was in 2008.
At the time they only made 3.5, 3.75 and 3.9 inch stroke Cleveland main journal
crankshafts but they have since added a 4" stroke version. Tom indicated all
of their SVO cranks were internal balanced. I asked about skirt clearance
with the shorter 6" rod required for a reasonable pin height in a 9.2" deck
351C block and he said I was the first one to ask about it. He confirmed the
3.9" stroke crank that I was interested in was designed for a 9.5" deck blocks
and 6.2" rods but was unable to say if there would be an issue or not with a
6" rod lengths. Understand that the K1 cranks are "SVO" type. They are
essentially a Windsor design with the main journals turned down to fit SVO
and other race blocks. For use in a 351C block, it will need a Ford Motorsport
snout spacer (part number M-19009-A341C, required with 351 SVO crankshaft when
used in production 351C engine). This part number is no longer available but
I have the dimensions to make one or there are timing sets with the spacer
built into the gear. The latter can be pricey and check to make sure a good
quality chain is used (not the inferior Rolon chain from India).

Subsequently, a European Cleveland drag racer order a 408C stroker kit which
used a 4" stroke K1 crank, 6.2" H-beam K1 rods and Wiseco pistons. When he
assembled it, the pistons stuck about 0.200" above the deck indicating the
pistons were designed for 6" rods. When he tried 6" rods, the piston skirts
hit the crank. It was my understanding that the kit was put together by
Wiseco.

> It is probably clear by now that I know nothing about engine balancing, or
> how its done, or what parts balance it.

A 90 degree crank V-8 needs a bob weight at each end to balance out the motion
of the reciprocating masses (pistons, pins, rings, and small end weight of the
rods). Internal/external balancing is a matter of where the two bob weight
masses are located or distributed. Internal (also referred to as neutral) and
external (more rarely referred to as Detroit balance). Neutral or internal is
where all of the balancing is done within the crankshaft (once the weights of
the rods are equalized) and the flywheel and balancer are symmetric (no balance
weights). With external balancing, some of the the balance mass is moved to
the damper and the flywheel. A V-8 has an unbalanced couple that rotates the
same direction and frequency as the crankshaft. To balance this, offset
weights are needed at the front and rear of the crankshaft. The farther away
from the center of the engine and from the center of the crankshaft these
weights are, the smaller they need to be. If this weight is inside the block,
it is considered to be internally balanced, if these weights are on the
flywheel and front pulley or damper, it is externally balanced. External
weights apply their force through the first and last main bearing. Moving the
weights inside means more force is needed, but it distributed over more main
bearings. In addition to these weights, other weights are placed on the crank
to minimize main bearing loads. From the factory, most 351C engines are
externally balanced and use a 28.2 Oz-In balance factor (HO and Boss 351C
were slightly different). Notice the units are ounce-inches. It's the product
of the mass (ounces) and the distance (inches) that is important. With
external balancing, both the flywheel and damper will have this imbalance and
not be symmetric. It's common for racers to internally balance but that
requires a matching flywheel and damper with zero balance factor.

Brent supplied the stroker kit for my 403C and internally balanced it. I used
a new old stock Schiefer neutral balance aluminum flywheel originally meant
for a Ford 300 truck inline six cylinder engine which shares the 351C's bolt
pattern and 164 teeth ring gear but is neutrally balanced.

Dan Jones
Quote
Like
Share

Joined: September 9th, 2010, 6:02 am

May 2nd, 2012, 6:35 pm #4

I assume that K1 internally balanced your rotating assembly. If that's true, then you will need a 0 balance flywheel and a 0 balance balancer. A stock 351C balancer/flywheel are imbalanced, so it won't work. Is there any documentation that you have which shows which way the rotating assembly was balanced?

And here's the "other thing..."

I don't know of any K1 forged crank that is setup for a Cleveland. By that, I mean that their cranks that I have seen are made for a 6.200" rod and the counterweights are larger for that reason. A 6.200" rod makes for an extremely short piston in a Cleveland (read 1" compression height). With that being said, which rod length did they use? If they used a 6" rod, I would do a quick mock-up and make sure that the pistons won't hit the counterweights at BDC.



Brent Lykins
B2 Motorsports, LLC





Hi Brent, thank you SO much for responding... Looks like the rods are 6.2" long, and the pistons are pretty short. Here are the specs on the piston sheet that came with the kit.

Comp Height: 1.280
Bore Size: 4.0300 (of course)
Suggested Clearance: 0.0035 (not sure what this means)

Then there is a sketch of the piston with a measurement that says its 1.300" from the bottom of the oil ring, to the bottom of the piston skirt. But when I measure this by hand I'm seeing 1 1/8" from below the piston pin to the oil ring, and 1 5/8" from the oil ring to the very bottom of the piston "skirt"? (the tails of the piston that hang down on the high and low side of the pistons) I have a couple pics...

[/IMG]

Is there a problem with having "shorty" pistons? As I add everything up, the K1 kit is going to cost me about $1,000 MORE than the scat kit, for taiwanese crap....
Quote
Like
Share

Joined: May 20th, 2005, 4:48 pm

May 2nd, 2012, 7:09 pm #5

They assumed you were using this crankshaft in a 351W SVO block.

If you take the measurements: (4" stroke divided by 2) + 6.200 + 1.280 = 9.480". It would be about .020" below deck on a 9.500" block. It will stick about .280" out of the hole on a Cleveland block.

Your only option at this point is to sell it all and start over with a Scat assembly....or buy a set of 408 Cleveland pistons, some 6" rods, and have a machinist turn down the counterweights so that they will clear the piston skirts.



Brent Lykins
B2 Motorsports, LLC






Quote
Like
Share

Joined: September 9th, 2010, 6:02 am

May 2nd, 2012, 7:15 pm #6

> I bought a rotating assembly from K1 technologies to bump my cubes up to 408
> and had them balance it at the factory.

Did you buy this directly from K1 (or perhaps from a vendor who supplied the
pistons to go along with the K1 crank and rods)? I wasn't aware that K1 did
a complete kit for Cleveland engines and don't see anything listed in their
current catalog. Do the pistons have valve reliefs for canted valve heads or
inline?

> Will it mess up balancing?

I spoke with Tom Molnar of K1 about their Cleveland cranks. This was in 2008.
At the time they only made 3.5, 3.75 and 3.9 inch stroke Cleveland main journal
crankshafts but they have since added a 4" stroke version. Tom indicated all
of their SVO cranks were internal balanced. I asked about skirt clearance
with the shorter 6" rod required for a reasonable pin height in a 9.2" deck
351C block and he said I was the first one to ask about it. He confirmed the
3.9" stroke crank that I was interested in was designed for a 9.5" deck blocks
and 6.2" rods but was unable to say if there would be an issue or not with a
6" rod lengths. Understand that the K1 cranks are "SVO" type. They are
essentially a Windsor design with the main journals turned down to fit SVO
and other race blocks. For use in a 351C block, it will need a Ford Motorsport
snout spacer (part number M-19009-A341C, required with 351 SVO crankshaft when
used in production 351C engine). This part number is no longer available but
I have the dimensions to make one or there are timing sets with the spacer
built into the gear. The latter can be pricey and check to make sure a good
quality chain is used (not the inferior Rolon chain from India).

Subsequently, a European Cleveland drag racer order a 408C stroker kit which
used a 4" stroke K1 crank, 6.2" H-beam K1 rods and Wiseco pistons. When he
assembled it, the pistons stuck about 0.200" above the deck indicating the
pistons were designed for 6" rods. When he tried 6" rods, the piston skirts
hit the crank. It was my understanding that the kit was put together by
Wiseco.

> It is probably clear by now that I know nothing about engine balancing, or
> how its done, or what parts balance it.

A 90 degree crank V-8 needs a bob weight at each end to balance out the motion
of the reciprocating masses (pistons, pins, rings, and small end weight of the
rods). Internal/external balancing is a matter of where the two bob weight
masses are located or distributed. Internal (also referred to as neutral) and
external (more rarely referred to as Detroit balance). Neutral or internal is
where all of the balancing is done within the crankshaft (once the weights of
the rods are equalized) and the flywheel and balancer are symmetric (no balance
weights). With external balancing, some of the the balance mass is moved to
the damper and the flywheel. A V-8 has an unbalanced couple that rotates the
same direction and frequency as the crankshaft. To balance this, offset
weights are needed at the front and rear of the crankshaft. The farther away
from the center of the engine and from the center of the crankshaft these
weights are, the smaller they need to be. If this weight is inside the block,
it is considered to be internally balanced, if these weights are on the
flywheel and front pulley or damper, it is externally balanced. External
weights apply their force through the first and last main bearing. Moving the
weights inside means more force is needed, but it distributed over more main
bearings. In addition to these weights, other weights are placed on the crank
to minimize main bearing loads. From the factory, most 351C engines are
externally balanced and use a 28.2 Oz-In balance factor (HO and Boss 351C
were slightly different). Notice the units are ounce-inches. It's the product
of the mass (ounces) and the distance (inches) that is important. With
external balancing, both the flywheel and damper will have this imbalance and
not be symmetric. It's common for racers to internally balance but that
requires a matching flywheel and damper with zero balance factor.

Brent supplied the stroker kit for my 403C and internally balanced it. I used
a new old stock Schiefer neutral balance aluminum flywheel originally meant
for a Ford 300 truck inline six cylinder engine which shares the 351C's bolt
pattern and 164 teeth ring gear but is neutrally balanced.

Dan Jones
Hi Dan, Thank you for saving my face.. If no one had responded to this post today, my face would look nothing like it does now

>Did you buy this directly from K1 (or perhaps from a vendor who supplied the pistons to go along with the K1 crank and rods)?

SO.. I bought the kit directly from K1, they recently (last year I think) partnered with wiseco to put out these kits. It has the 6.2" rods, and shorty pistons. Is this a problem for a mostly street, and occasionally strip engine?

>Do the pistons have valve reliefs for canted valve heads or inline?

Yes they are dished, with valve reliefs. Here is a pic: [/IMG]

Is the stock 351C deck height 9.5 or 9.2? I can start measuring and actually figure out if they will clear or not... I WOULD just mock it up and see, but this "kit" didn't come with bearings either... So I can't at the moment, until I spend even MORE money on bearings. The kit is basically pistons, rods, crank, balancing. For $2250 including tax.. Anyway, I'll try and stop ranting.

Thanks a ton for all the info on balancing Very informative sir. It is internally balanced, which I like the idea of, but the extra money for a damper and flywheel is a downer.. considering the scat kit comes with both for about $2000. For the record, the only reason I went with K1 was because scat is out of stock on the 408 cranks until at least the end of May. (which when I started all this, seemed like a long time away. Now, not so long)

Again, thank you so much for your time! I TRUELY appreciate you guys on this forum... This build would be completely impossible for me without you.
Quote
Like
Share

Joined: September 9th, 2010, 6:02 am

May 2nd, 2012, 8:38 pm #7

They assumed you were using this crankshaft in a 351W SVO block.

If you take the measurements: (4" stroke divided by 2) + 6.200 + 1.280 = 9.480". It would be about .020" below deck on a 9.500" block. It will stick about .280" out of the hole on a Cleveland block.

Your only option at this point is to sell it all and start over with a Scat assembly....or buy a set of 408 Cleveland pistons, some 6" rods, and have a machinist turn down the counterweights so that they will clear the piston skirts.



Brent Lykins
B2 Motorsports, LLC





wow... thats a pretty hard blow. you are absolutely right though. I looked up the part number and it is for a W block. i called k1 and they guy is going to "talk to his product manager" and see if they will let me return it. i'm not very hopeful, he said he would call me back tomorrow. that pretty much stops my build for another year.. but if you've already waited 17 years, whats one more right? FML
Quote
Like
Share

Joined: October 1st, 2004, 8:05 pm

May 2nd, 2012, 8:44 pm #8

Hi Dan, Thank you for saving my face.. If no one had responded to this post today, my face would look nothing like it does now

>Did you buy this directly from K1 (or perhaps from a vendor who supplied the pistons to go along with the K1 crank and rods)?

SO.. I bought the kit directly from K1, they recently (last year I think) partnered with wiseco to put out these kits. It has the 6.2" rods, and shorty pistons. Is this a problem for a mostly street, and occasionally strip engine?

>Do the pistons have valve reliefs for canted valve heads or inline?

Yes they are dished, with valve reliefs. Here is a pic: [/IMG]

Is the stock 351C deck height 9.5 or 9.2? I can start measuring and actually figure out if they will clear or not... I WOULD just mock it up and see, but this "kit" didn't come with bearings either... So I can't at the moment, until I spend even MORE money on bearings. The kit is basically pistons, rods, crank, balancing. For $2250 including tax.. Anyway, I'll try and stop ranting.

Thanks a ton for all the info on balancing Very informative sir. It is internally balanced, which I like the idea of, but the extra money for a damper and flywheel is a downer.. considering the scat kit comes with both for about $2000. For the record, the only reason I went with K1 was because scat is out of stock on the 408 cranks until at least the end of May. (which when I started all this, seemed like a long time away. Now, not so long)

Again, thank you so much for your time! I TRUELY appreciate you guys on this forum... This build would be completely impossible for me without you.
If they won't let you return your kit ... box it back up in the shipping material it was shipped to you in and sell it on eBay to a 351W owner. Recoupe 75% of what you spent on it.

Put on your race face and get back in the game.

-G
Quote
Like
Share

Joined: December 22nd, 2003, 3:29 am

May 2nd, 2012, 9:37 pm #9

Hi Brent, thank you SO much for responding... Looks like the rods are 6.2" long, and the pistons are pretty short. Here are the specs on the piston sheet that came with the kit.

Comp Height: 1.280
Bore Size: 4.0300 (of course)
Suggested Clearance: 0.0035 (not sure what this means)

Then there is a sketch of the piston with a measurement that says its 1.300" from the bottom of the oil ring, to the bottom of the piston skirt. But when I measure this by hand I'm seeing 1 1/8" from below the piston pin to the oil ring, and 1 5/8" from the oil ring to the very bottom of the piston "skirt"? (the tails of the piston that hang down on the high and low side of the pistons) I have a couple pics...

[/IMG]

Is there a problem with having "shorty" pistons? As I add everything up, the K1 kit is going to cost me about $1,000 MORE than the scat kit, for taiwanese crap....
Pretty sure I read that K1 rods start out as chineese blanks just machined better and checked over better, not sure if machined here or in China. Callies Compstar line is the same way. Guess they figure if you can't beat them join them!
Quote
Like
Share

Joined: May 20th, 2005, 4:48 pm

May 2nd, 2012, 9:53 pm #10

wow... thats a pretty hard blow. you are absolutely right though. I looked up the part number and it is for a W block. i called k1 and they guy is going to "talk to his product manager" and see if they will let me return it. i'm not very hopeful, he said he would call me back tomorrow. that pretty much stops my build for another year.. but if you've already waited 17 years, whats one more right? FML
If they won't cooperate, maybe we can figure out a way around it. I build a ton of Windsor strokers, so maybe we could work a deal on a trade of pistons and a set of rods. A willing crank shop could turn those counterweights down so that the rods would clear.

Brent Lykins
B2 Motorsports, LLC






Quote
Like
Share