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[johnmowcop]

Hello.

Below is part of a discussion I am having with a friend about torque plates. At the end of the narrative I ask for:

""As you say, the way to prove this lot is to measure the barrels prior to clamping between the plates, measure them when they are clamped prior to machining, measure them after machining but prior to releasing the clamping plates and then again after the clamping plates are removed. Those readings would be interesting.

I will put this on the Harley Forum to see if anyone has the figures available.""

Has anyone got these figures we can use in our discussion.

This is our discussion:

"I think torque plates are so heavy to prevent them deflecting/deforming when tightened up to the 42ftlb torque that is required to replicate the torquing down of the head and barrel onto the engine case.

I understand  that the barrels are originally machined free of any similar clamping arrangement (well I have no proof of this, it just makes the argument stick really. I mean if this problem is so widely recognised why don't Harley use clamping plates themselves to bore out the barrels). So when they come of the boring machine in Harley USA or China, wherever they are made, (assumed free of clamping plates), they are round. This is to a certain extent confirmed by the measurements of my barrels. I have measured that they are only 0.001 ins out of round withou clamping plates (and even that could be down to my measuring incapability).

When they are mounted in the engine and torqued up, and possibly influenced by temperature from the combustion, they deform. to some extent I can believe this because when you see the barrels in the flesh there is not much solid metal about (plenty of finning, but not much solid stuff). By machining accurately round within the torque plates, they must go back to round when subjected to the the torquing procedure in the engine rebuild.

As you say, the way to prove this lot is to measure the barrels prior to clamping between the plates, measure them when they are clamped prior to machining, measure them after machining but prior to releasing the clamping plates and then again after the clamping plates are removed. Those readings would be interesting.

I will put this on the Harley Forum to see if anyone has the figures available."

Please feel free to offer advice or observations.

JohnT

[Fired00d]

Hello.

Below is part of a discussion I am having with a friend about torque plates. At the end of the narrative I ask for:

""As you say, the way to prove this lot is to measure the barrels prior to clamping between the plates, measure them when they are clamped prior to machining, measure them after machining but prior to releasing the clamping plates and then again after the clamping plates are removed. Those readings would be interesting.

I will put this on the Harley Forum to see if anyone has the figures available.""

Has anyone got these figures we can use in our discussion.

This is our discussion:

"I think torque plates are so heavy to prevent them deflecting/deforming when tightened up to the 42ftlb torque that is required to replicate the torquing down of the head and barrel onto the engine case.

I understand  that the barrels are originally machined free of any similar clamping arrangement (well I have no proof of this, it just makes the argument stick really. I mean if this problem is so widely recognised why don't Harley use clamping plates themselves to bore out the barrels). So when they come of the boring machine in Harley USA or China, wherever they are made, (assumed free of clamping plates), they are round. This is to a certain extent confirmed by the measurements of my barrels. I have measured that they are only 0.001 ins out of round withou clamping plates (and even that could be down to my measuring incapability).

When they are mounted in the engine and torqued up, and possibly influenced by temperature from the combustion, they deform. to some extent I can believe this because when you see the barrels in the flesh there is not much solid metal about (plenty of finning, but not much solid stuff). By machining accurately round within the torque plates, they must go back to round when subjected to the the torquing procedure in the engine rebuild.

As you say, the way to prove this lot is to measure the barrels prior to clamping between the plates, measure them when they are clamped prior to machining, measure them after machining but prior to releasing the clamping plates and then again after the clamping plates are removed. Those readings would be interesting.

I will put this on the Harley Forum to see if anyone has the figures available."

Please feel free to offer advice or observations.

JohnT

I think you've answered your conundrum yourself... JMHO but I believe they are machined w/o the tq plates (remember wherever they are made <USA/China>) they are mass produced (1000's at a time). They are believing their machining process are making them within specs/tolerances so they don't bother to apply tq plates and verify. Anything mass produced will have some hiccups... some will be good... some will have problems... same reason some of us have similar problems w/our bikes and others don't. Manufacturer's are hedging their bets that more will be ok than will not.

There well could be some deformity after assembly but if there is no verification prior that they were round then how can you/we confirm that they were/weren't prior to tq?

The only way to truly know/confirm when building a high performance (or reliable) motor is to check/confirm all specs prior to and during assembly.

 
Ride Safe,
Fired00d
 

[Chains]

Don't know Harley's machining process but when I worked in the tool room at Chrysler where the V2 compressors were made for auto air conditioning the process was as follows.

(1) castings were loaded into a dial machine clamped in a fixture and the faces were machined to qualify them for the next step.
(2) operator unloaded the parts as they came around and set them on a pallet shuttle conveyer with areas to be bored facing front to back of the shuttle.
(3) holes for mounting the heads were drilled and tapped front and rear at the same time. A floating drill jig kept pressure on the faces machined in operation 1.
(4) next operation was to bore the cylinders front and rear. A floating torque plate located in the holes put in to mount the head and kept pressure on face.
(5) bores were honed front and rear a floating hone plate located in same holes used to bolt the cylinders and applied pressure on the faces.

There were many other operations for various holes and ports as well as inspection and wash operations as well. I shot tool trouble over 4 lines that were close to 100 feet long each back in 1970. That is how it was done for their products at that time.

I'm sure the process Harley uses is automated but to what extent I don't know.

[HILLSIDECYCLE.COM]

And always keep in mind that these air/oil cooled engines have thermal expansion/contraction.
Scott

[prodrag1320]

where did you hear HD dosnt T. plate the cylinders when honed at the factory?? sure they are.its not a plating set up like most of us use,but a plating system that can hone multiple cylinders at a time (saw it on a tour of the wisc. HD plant in the evo days,but im sure its still done the same way)

[HD Street Performance]

Exactly.
But today they have automated the process. Pressure plates are put in place as the bore \ hone is done.

[HILLSIDECYCLE.COM]

...........and they still move around.
Scott

[HD Street Performance]

The metal is new, not seasoned. In a perfect world they would stay true but after measuring as many as I have most are not true. That is not a function of poor machine work or wear.
Distortion due to uneven heating and cooling or overheating is my theory. Once the metal is seasoned they seem to remain relatively stable after the first bore job.
Looks like plates used to me..

[johnmowcop]

The metal is new, not seasoned. In a perfect world they would stay true but after measuring as many as I have most are not true. That is not a function of poor machine work or wear.
Distortion due to uneven heating and cooling or overheating is my theory. Once the metal is seasoned they seem to remain relatively stable after the first bore job.

I wonder if this indicates a bit of stress relieving/normalising of the combined Aluminium casting and cast Iron liner is going on (from the casting process) at the operating temperatures of the engine. Then once the stresses are relieved along with some deformation of the previously machined casting (this could also apply to the liner). Once the deformation has taken place the whole combined cast iron liner/Aluminium casting becomes stable. Which is what you could be referring to by your statement "Once the metal is seasoned they seem to remain relatively stable after the first bore job".

Is there a Metallurgist out there who could comment on this?

Below, for interest, is an excerpt from   http://webhotel2.tut.fi/projects/caeds/tekstit/metals/metals_aluminum.pdf 

T5
Direct thermal ageing, which is done without any prior solution heat treatment. The
casting is usually heated to 150‐170°C for 8‐10 minutes, and is then left to cool in the
air. After some time in the furnace, the material acquires maximum hardness which
thereafter decreases. Thermal ageing contributes to the separation of hardening parti‐
cles. 
T6
Complete age hardening, which is achieved by a thermal treatment in three stages: 
solution heat treatment, cooling and ageing.   The solution heat treatment is usually
conducted at 520‐530 °C for three hours or more, depending on casting thickness and
the type of alloy. The heat treatment is followed by rapid cooling, then by natural
ageing for 24 hours. After that, the casting is thermally aged at 150‐170°C for ca. 5‐15
hours, depending on casting thickness and the type of alloy; during this period, age‐
hardening particles are formed. Thermal ageing is followed by cooling at room tem‐
perature. 
T7
Solution heat treatment and averaging, i.e. thermally aged beyond the point of maxi‐
mum hardness.54 
F
As cast.
Stress‐relief annealing
Stress‐relief annealing is often carried out in connection with machining, which often
results in deformation due to the release of internal tensions in the casting. Annealing
usually occurs at 315‐345°C for 2‐4 hours.

[HD Street Performance]

I don't know what thermal or process heat treatment the cylinders are subjected to but over the years i've obstabl some are rock solid and others are never stabilize.
Very interested in the topic.

[TorqueInc]

other than the Mercury castings,harleys aluminum doesn't really fit into any castable aluminum grade it is more akin to a die casting alloy than a conventional cast aluminum.

 My guess would be ...that is the reason they aren't very stable....add in liners being a little too thin for the bore sizes....imo

  Are you better off doing ANY performance build using seasoned cylinders.....YES

My seasoning process used to include my shop oven with a slow heating process with a slow cooling....now I just take them to the powder coater and have them take a trip or two thru the powder coating oven.....and it works.

  This was confirmed by both delkron and a recent trip to Ultima....very informative

  Mondello preached cryo treating them ....I don't think it would hurt but unless you can catch a cryo facility inbetween production runs it is very expensive.

[johnmowcop]

other than the Mercury castings,harleys aluminum doesn't really fit into any castable aluminum grade it is more akin to a die casting alloy than a conventional cast aluminum.

 My guess would be ...that is the reason they aren't very stable....add in liners being a little too thin for the bore sizes....imo

  Are you better off doing ANY performance build using seasoned cylinders.....YES

My seasoning process used to include my shop oven with a slow heating process with a slow cooling....now I just take them to the powder coater and have them take a trip or two thru the powder coating oven.....and it works.

  This was confirmed by both delkron and a recent trip to Ultima....very informative

  Mondello preached cryo treating them ....I don't think it would hurt but unless you can catch a cryo facility inbetween production runs it is very expensive.

Not sure about the process for Aluminium, diecast or other wise. But your "seasoning" in  the oven replicates stress relieving of steel fabrications after fabrication and before machining, They are heated to about 700degc. Held at 1hr per inch thickness, then cooled in the oven (slow cool).

I am beginning to believe this is what's going on with these cylinders. But the "oven" is the engine running at temperature.

JohnT

[HD Street Performance]

When the stock cylinders are sleeved with a .090 wall ductile iron sleeve they are very stable.

[GMR-PERFORMANCE]

Great video .. I always laugh when I see the pistons banging around and ring pack snagging on the stud threads.. No lube just sling it into the bore ..

[johnmowcop]

When the stock cylinders are sleeved with a .090 wall ductile iron sleeve they are very stable.

Not sure if it means the same in USA but ductile Iron here is SGI Spheroidal Nodular Graphite cast iron. It has "free" nodules of graphite that provide a less brittle/hard cast iron. Has the name suggests is more ductile than cast iron. Machines easier, and is "tougher". In the fifties/sixties Matchless produced a 650cc vertical twin (actually 500 and 600 before they got it to 650) this had initially a cast iron crankshaft, when they got to the larger engine size they experienced crank failures (I presume due to the brittleness of the crank) they changed the material to SGI (Ductile Iron) which solved the problem, at least on the road bikes. Not sure what I wrote is relevant but it just came to mind.

JohnT