Bald Eagle Aviation

51fixer · **Posted:** Fri Aug 06, 2010 10:24 pm

Lynn Allen wrote:

Rich, anything new over there going on??

Lynn

You must have read my mind. I brought the camera home tonight but can't find the d---m card reader to post the pics.
Jim has BE at Michigan with the Horsemen this weekend.
I have pics of the Roush cam and valve timing on a Merlin using a dial indicator from doing the 50 hr engine insp.
Also I am overhauling a Spifire tailwheel we got from ebay over in the UK. It looks NOS with tire and axle but had enough corrosion to make disassembly a pain. I had to cut the tire on the bandsaw and drill out the 4 studs to separate the 2 wheel halves. It looks like it will be usable. The bearings used are the same Ford used on front wheels from 1928 to 1948. Model As to Ford tractors used the same cone and race. Dunlop made 3 different tailwheels that were used on the Griffon Spits, probably other mks as well. Of course this ebay unit is different from the current one fitted although some parts are used on both units.
Hopefully will post some pics soon.
Rich

51fixer · **Posted:** Sat Aug 07, 2010 7:05 pm

Some pics from the Merlin valve train inspection on the Roush engine in BE-

Roush cams are based on the Merlin 620 series Transport cams. They are made under a FAA PMA. They added the hex unit to facilitate being able to rotate the cam for valve train timing.

The drive gears for the cam. There is a vertical vernier shaft that you make adjustments to time the cam.

Close up of a set of cam lobes and Merlin Fingers.

Roush ignition harness, another PMA system.

The Champion Auto Race plugs used in the Roush ignition.

Rich

Lynn Allen · **Posted:** Sat Aug 07, 2010 7:39 pm

Thanks for the update and photos. Guess they have normal auto leads to the spark plugs??

51fixer · **Posted:** Sat Aug 07, 2010 7:45 pm

We recently acquired a Spitfire tailwheel from ebay in the UK.
What it looked like on arrival-

Knowing the exterior didn't look to bad I figured that it would have some internal corrosion and it didn't disappoint-

I couldn't get the rim to separate into the 2 halves so I started by cutting the tire. It was an AERO brand tire casing.

The rim excised.

I had trouble finding a way to hold the rim and apply force to separate the halves. I finally used the steady rest I have to grab on one of the wheel halves.

But it still wouldn't budge. I was afraid of damaging it so I decided to drill out the studs.

Back into the steady rest and after some taps with a punch into the drilled out studs I had movement.

More movement.

Success. Note the studs have a flange at the base which is secured by an 1/8" pin driven into a hole half drilled into the flange and half into the wheel.
I'll show more later.
Rich

51fixer · **Posted:** Sat Aug 07, 2010 7:46 pm

Lynn Allen wrote:

Thanks for the update and photos. Guess they have normal auto leads to the spark plugs??

I guess race car quality leads and wire.

Rich

51fixer · **Posted:** Sat Aug 07, 2010 10:48 pm

Further steps performed-

Cleaned up by plastic media blasting. This removed most of the oxidized corrosion residue and allowed me to see what was there.
I followed this with glass bead blasting on areas that didn't clean up with the plastic media. I also then tried to remove the pins used
to stop the studs from rotating so the remainder of the studs could be removed. There was nothing to grab unfortunately so back to the mill.

I drilled the pins using a very small center drill with around a 1/16" tip.

Then I used a stripped screw remover in my hand held drill in reverse.

This spun the pin and grabbed it enough to pull it out.

The last step was drilling an 1/8" hole in the stud remainder in which I tapped a stud remover. I dropped the collar over it and turned it out with a wrench.

Ready for NDT.
I had hoped Supermarine would have the 4 studs for this on the shelf. It just happens they are overhauling one of these for BBMF so no such luck.
I wonder why they just didn't use through bolts rather that the 1/4 BSF threaded studs. 1/4-26 TPI is what the the 1/4 BSF uses.
I just have to remember that it British.
Rich

51fixer · **Posted:** Sat Aug 07, 2010 10:58 pm

My son found the tailwheel on ebay but a little internet searching discovered the ebay seller bought it here last June-

http://www.tennants.co.uk/Catalogue/Lots/71629.aspx

Wish we had payed only 70 lbs for it. I guess there is still capitalism in the UK.

Rich

Lynn Allen · **Posted:** Sun Aug 08, 2010 9:46 am

A lot of work for e eBay treasure. Thanks for the step by step.....

Chris · **Posted:** Sun Aug 08, 2010 11:04 am

[quote][/quote] had hoped Supermarine would have the 4 studs for this on the shelf. It just happens they are overhauling one of these for BBMF so no such luck.
I wonder why they just didn't use through bolts rather that the 1/4 BSF threaded studs. 1/4-26 TPI is what the the 1/4 BSF uses.
I just have to remember that it British.
Rich

You mean the British over engineer stuff? Whooda thunk? Never use ten parts when you can do the exact same job and use fifteen parts. Not complaining because the British stuff works well and is elegantly designed, just a bit of overkill.

Lynn Allen · **Posted:** Sun Aug 08, 2010 9:51 pm

51fixer wrote:

Lynn Allen wrote:

Thanks for the update and photos. Guess they have normal auto leads to the spark plugs??

I guess race car quality leads and wire.

Rich

When you get a chance, could you post a picture of them...

Thanks

51fixer · **Posted:** Sun Aug 08, 2010 10:09 pm

Lynn Allen wrote:

51fixer wrote:

Lynn Allen wrote:

Thanks for the update and photos. Guess they have normal auto leads to the spark plugs??

I guess race car quality leads and wire.

Rich

When you get a chance, could you post a picture of them...

Thanks

Page one of the thread shows them installed on the black motor about half way down. This went into Princess way back when.
I suppose there are other pics throughout the last 62 pages.
Maybe a good reason to reread everything. :wink:

Rich

Lynn Allen · **Posted:** Sun Aug 08, 2010 10:59 pm

Roger that...... :wink:

51fixer · **Posted:** Tue Aug 10, 2010 9:12 pm

As I wait for the gents at Supermarine to get back to me the tailwheel sits-

The original bearings were Made in England. The new replacements are made in Canada. All Timken.

Since we have around 5 hrs on the Spit since the new Cam Racks were built up and install I crossed my fingers and opened up the Rocker Covers-

Everything looks good.
Since I have now used the Roush method of cam timing I tried to apply that technology to the Griffon.
By the book for Griffon 58 Cam Timing involves some subjective feel. With the Merlin and Griffon you basically are tuning 2 six cylinder engines to run in harmony.
There is a set of index marks on a crankshaft coupler that is your reference. When the proper mark is aligned with an arrow on the crank you rotate the cam to a certain position marked by a .... Wait, there isn't any mark. Depending on the type of cam you have there is a couple different by the book ways of setting up the cam
For the Griffon 58 cam it follows something like this-
On the Intake valves on B-1 or A-6 cylinders adjust 1 of the 2 Intake Valve Fingers to a clearance of .023" measured between the base of the cam lobe and the striker pad on the finger.
You rotate the cam lobe so the lobe's highest point faces away from the pad on the finger and adjust the .023". Then you rotate the cam in the direction of rotation until it "nips" a .003" feeler gauge inserted between the cam lobe and the finger pad. You then engage the vernier cam drive shaft and check your work by reversing the direction of the prop and rotate back fwd until the feeler gauge gets nipped by the cam. Then you check the crank marks and continue to make adjustments until your happy with the results. Then you do the same to the other bank. Also along the way you needed to be sure your on the right stroke if you are doing this with the magnetos already installed.

The Roush method is taking race engine set up techniques and applying them to the Merlin. They have measured valve displacement of the intake valve at TDC with the cams set up per the book method. 1st is you set the valve lash to .000. You set up a dial indicator on .000 with the cam lobe turned away from the finger. The indicator extension rests on the top of the valve spring retainer. You set the crank to its TDC and rotate the cam in its proper direction until the valve moves the prescribed amount and then set the drive in place. It still requires a bit of back and forth but the results are easy to view and repeatable with the opposite cam. The Roush guys want around a max of .002" difference between the A and B cams. Using the normal book method you can induce around 6-7 degrees of difference and you can't know your that far out. The engine runs pretty good that way but with the Roush Method your are right on and you can know that.

To apply this to the Griffon I 1st checked my cam timing by the 58 book. .023 and .003. I then backed up the engine to get the cam lobe vertical, adjusted the finger to .000 lash and installed a dial indicator.

I rotated the crank to top dead center as marked for Cylinder B-6 and read the number off the dial indicator. I repeated this a number of times to insure repeatability of the results.
The number was .145".
I then set up the dial indicator and .000 lash on cyl A-1. I rotated to A-1 TDC and found my reading to be .162. About .017" more than the B cam. I pulled the drive shaft and rotated the cam and got the A cam to .146. This is within a couple thou and should be better than a difference of .017".

Dial indicator set to .000.

Set to TDC and .145.
I will adjust valves, clean spark plugs and run tomorrow so I'll hope for the best.
Rich

Lynn Allen · **Posted:** Tue Aug 10, 2010 9:47 pm

What he said. Using todays tech on old engines..... :shock:

wow

John Beyl · **Posted:** Wed Aug 11, 2010 12:06 pm

Hi Rich,

What kind of life do you get out of the automotive plugs in the Merlin? I'm thinking of going that route in our next engine to save cost...don't need to tell you how much Lodge plugs are running these days!

I like the Roush method of timing the cams. Do you have a cut sheet that details it or should I call them?

How often do you change oil in BE?

Thanks,
John

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