74" Cylinder growth verse Intake manifold gap

[BigLakeBob]

Ok, I had a little extra time this evening to do a quick test on one of my personal bikes, a 71' shovelhead .
I put it in my test cell and ran it up to 238F. Could have gone farther in temperature I know but just wanted to try this quick on that type of engine.
I set up the tooling and it grew exactly 0.023" from 68F to 238F as a range being test. This was overall summative growth on a 1971 74" FLH in that temperature range for what that's worth...
Duke

What grew .023, height? Thanks.

[dukekleman]

Bob,
I establish a base height value of the rear cylinder on the engine . Location was at the top center of the rocker box itself. I ran it to the temperatures of 68-238F and back to 68F. Watched the growth... In that particular temperature range, which was measured with a thermocouple at the intake area of the cylinder head, it changed the 0.023".
Duke

[T. Cotten]

Sounds reasonable, Duke!

If your Pan elongates similarly, how much would the gap between nipples widen?

(My geometry skills sined out when I never used them...)

If .023" is total cylinder growth, how do we apply that to inlets somewhere in the middle?

....Cotten

[dukekleman]

I know right, I'll do some calculations and probably a little more testing. It'll be a process due to the materials used in that particular area. Calculations won't be spot on accurate. Back to measuring I guess ...A wise man once told me "Unless your measuring, your just guessing"

[T. Cotten]

I really don't know how it could be measured, Duke,..

But on any machine with a 'plumber's' manifold, it would be wonderful to know the triangular distances from the top center case stud (center) to the two nipple rivets (centers), and how they change.

If my life depended upon it, I would cut paper and make dirty finger rubbings.

We all know these thing grow and shrink for hundreds if not thousands of cycles; The mystery is how they survive!

....Cotten

[Steve Swan]

Sounds reasonable, Duke!

If your Pan elongates similarly, how much would the gap between nipples widen?

(My geometry skills sined out when I never used them...)

If .023" is total cylinder growth, how do we apply that to inlets somewhere in the middle?

....Cotten

"...sined out..." no pun intended... sine is trigonometry

[T. Cotten]

"...sined out..." no pun intended... sine is trigonometry

Forgive me, Steve,...

But once the third, fourth, and all those extra axis got added,... Its all just geometry to me.

How would those three centers be scanned and plotted in the Twenty-First Century?
Cell phone app?

Little dots of white paint?

...Cotten

[Steve Swan]

Tom, i disclosed everything i know about geometry and trig...

[T. Cotten]

... set up the tooling and it grew exactly 0.023" from 68F to 238F as a range being test. ...

Can you please describe your 'tooling', Duke?

Thanks in advance,

.....Cotten

[dukekleman]

I installed a thermocouple in the cylinder head area of the Intake manifold. This was how I monitored temperature digitally. I made up a simple fixture plate I attached to the frame, this allowed me to install Dial indicators on the rocker box that I zero'd out.
With the engine running, I was able to watch the growth on the Dial Indicator up to a temperature of 238F . Shutting off the engine, the needle stayed at a growth of 0.023" . I turned on the cooling fans in the test cell and watch the needle go back to zero at 68F, right where I started.
Duke

[T. Cotten]

Couldn't you do the same directly on the top of a Pan manifold, Duke?

That top center case stud is convenient to mount an indicator, although you would have to remove any annoying Jubillee horn of course. (I always charged accordingly for the cursed things.) Speedo cable clamp is friendly.

Left my thermocouples where I worked; My infra-red gun works pretty good; Finally got the 'fridge tuned.

Wait a minute. Didn't the motor vibes make the indicators bounce?

....Cotten

[dukekleman]

Couldn't you do the same directly on the top of a Pan manifold, Duke?

That top center case stud is convenient to mount an indicator, although you would have to remove any annoying Jubillee horn of course. (I always charged accordingly for the cursed things.) Speedo cable clamp is friendly.

Left my thermocouples where I worked; My infra-red gun works pretty good; Finally got the 'fridge tuned.

Wait a minute. Didn't the motor vibes make the indicators bounce?

....Cotten

Yes indeed, growth measurements have been done at the manifold area in the past. Typically in a test cell for engine testing or a test cell for chassis testing without fuel tanks mounted. What is interesting to learn about is the upper center motor mount. The type of material used, it's design features along with it's effects on growth allowance, frequency transmission and strain application. We've all seen the aftermarket make many versions of these mounts as well as material changes, Good or Bad? Others can decide.

As far as Dial Indicator movement, I know the background of the particular bike I used the other day, torque values on all the fasteners, meaning nothing was loose.
Surprisingly or Not...the needle at Idle moved back and fourth a total of 0.0015" ( Fifteen ten thousandths only). Seeing the needle return to Zero after full cool down verified accuracy and stability of the fixturing used.

[T. Cotten]

....What is interesting to learn about is the upper center motor mount. The type of material used, it's design features along with it's effects on growth allowance, frequency transmission and strain application. We've all seen the aftermarket make many versions of these mounts as well as material changes, Good or Bad? Others can decide....

You lost me, Duke.

I've never encountered anything but the real steel thing.

(One thing for sure, if its missing, the motor ain't balanced.)

If we knew the growth from the center case bolt to the manifold, we should be able to calculate the change at the seals, where wear occurs:
MAXWEAR.jpg

spgtwear.jpg

WRMANI.jpg

....Cotten

[dukekleman]

The unfortunate common markings always seen after numerous miles and heat cycles through everyday operation. The peek intake seal is very friendly to the intake manifold by comparison to the brass.

[T. Cotten]

...The peek intake seal is very friendly to the intake manifold by comparison to the brass.

Absolutely, Duke!

When they fit.

....Cotten
PS: It would still be usefull to know how much the assembly expands, Thanks again.