Lockdown: Time for big service, changes and improvements of my SQ4

Singles, twins and fours.
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rschurr
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Lockdown: Time for big service, changes and improvements of my SQ4

Postby rschurr » Fri Jan 15, 2021 7:09 pm

I toke the chance (have now the time!) to make a total strip down of my SQ4 for revivising and improvments (hopefully!):

IMG_20201216_151607 (Mittel).jpg
IMG_20201227_123129 (Mittel).jpg

Regrinding the crankshafts, added some Mallory Metal.
Now all Bob weigths, all rods and all pistons equalized in weigth.
Static balancing of the crankshafts with counterweigths.
Nearly perfect valve timing.
Valve timing.png

Repositing the oil filter in a hided position.
New clutch sproket with 40 Tooth.
IMG_20210116_081406.jpg

IMG_20201227_123129 (Mittel).jpg

Installing a BMW TLS brake .

But no chance for testing, we have 1 meter of new snow.

Cheerio Rudolf
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IMG_20210115_162256 (Mittel).jpg
1923 James Model 12 500ccm v-twin -- 1960 Chevrolet Corvette C1
1926 Douglas EW 350ccm flat-twin -- 1967 Chevrolet Corvette C2
1936 Motosacoche 500ccm single --- 1979 Chevrolet Corvette C3
1948 BSA A7 500ccm parallel twin -- 1955 Ariel Square Four MKII :!:

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Bob.Murphy
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby Bob.Murphy » Sat Jan 16, 2021 10:03 am

Lovely work, it should go very well. Let's see some pictures when the snow clears.

BUT -

I'd love to see pics of those three Chevvy Corvettes - please :mrgreen: :mrgreen: .

Bob (more into Toyota Landcruisers . . But if its got an engine . . . . ;) ).
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH

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rschurr
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby rschurr » Sat Jan 16, 2021 10:33 am

Ok here is my Corvette family:
Alle Cs II (Large).JPG


The C3 is Stock but goes 13,25 sec on 400 meters:
IMG_20210116_112627.jpg


and has now a new painting:
IMG_8410.JPG


The C2 has Triple Dual Carbs:
IMG_20160427_123329.jpg


The C1 has Dual Quads:
Dual Quad after.jpg
1923 James Model 12 500ccm v-twin -- 1960 Chevrolet Corvette C1
1926 Douglas EW 350ccm flat-twin -- 1967 Chevrolet Corvette C2
1936 Motosacoche 500ccm single --- 1979 Chevrolet Corvette C3
1948 BSA A7 500ccm parallel twin -- 1955 Ariel Square Four MKII :!:

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fpassmore
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby fpassmore » Sat Jan 16, 2021 3:19 pm

Very, very fine cars, my brother-in-law has five of them and it is quite an obsession.
Frank
'51 SQ4, '56 NH, '56 VH, '36 VH500 Red Hunter, '56 SQ4 (basket case), '49 Sq4 (basket case), '48 A7 BSA Twin, too many other BSA's, Norton's, Triumph's, Ducati's and Japanese to list. Just crazed is all my problem is.

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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby allan.walker » Sat Jan 16, 2021 3:59 pm

Hello Rudolf,
Some fine cars there!

Nice work on the Square Four, too. May I ask how you balanced the crankshafts? I know what Mallory metal is, but what procedure did you follow to determine where to add or remove weight, etc?

Allan.

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rschurr
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby rschurr » Sat Jan 16, 2021 6:25 pm

Hi Allen,
I followed exactly the AOMCC con-rod booklet (by Bruce Longman).

Engine balancing AOCCM.png


I weighed the con-rods and determined the proportion of the big end.

Big end weigth.JPG


Then I used strips of lead to simulate the determined weight. I tightened these strips around the crank pins and then turned the crankshaft on the balancing stand. The crankshaft must stop in all positions and no longer turn itself, then it is "static" balanced.
Also with lead strips I determined how much more the bob-weights should be heavier.

Now I brought the bob-weights in each case to the same weight (con-rods and pistons of course as well) and added the tungsten rods using the formula weight of tungsten rod minus weight of the drilled steel, I achieved a net 23 grams per bob-weight.

Finito !

Rudolf
1923 James Model 12 500ccm v-twin -- 1960 Chevrolet Corvette C1
1926 Douglas EW 350ccm flat-twin -- 1967 Chevrolet Corvette C2
1936 Motosacoche 500ccm single --- 1979 Chevrolet Corvette C3
1948 BSA A7 500ccm parallel twin -- 1955 Ariel Square Four MKII :!:

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Bob.Murphy
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby Bob.Murphy » Sat Jan 16, 2021 6:55 pm

Rudolf

Thanks for the Corvette pictures - very nice cars indeed. I guess you spend a lot of time keeping them 'just right'. They are a credit to you.

Bob.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH

allan.walker
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby allan.walker » Sun Jan 17, 2021 12:43 pm

rschurr wrote:Hi Allen,
I followed exactly the AOMCC con-rod booklet (by Bruce Longman).



I weighed the con-rods and determined the proportion of the big end.



Then I used strips of lead to simulate the determined weight. I tightened these strips around the crank pins and then turned the crankshaft on the balancing stand. The crankshaft must stop in all positions and no longer turn itself, then it is "static" balanced.
Also with lead strips I determined how much more the bob-weights should be heavier.

Now I brought the bob-weights in each case to the same weight (con-rods and pistons of course as well) and added the tungsten rods using the formula weight of tungsten rod minus weight of the drilled steel, I achieved a net 23 grams per bob-weight.

Finito !

Rudolf


Thank you Rudolf. I think that I can follow that!
I have an odd pair of crankshafts which I would like to check for balance before use.

Are they the original con rods that you are using? If so, have you carried-out any checks on them (e.g. crack testing?)
Are you going to polish them before re-use?

Allan.

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rschurr
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby rschurr » Sun Jan 17, 2021 5:09 pm

HI Allen,
The picture with the scales shows a BSA connecting rod as example.
I got a bunch of new AOMCC con rods after one of my old ones got cracked (fatigue fracture ).

IMG_20200520_193558.jpg


And so I got the booklet that I have my knowledge of. In the excerpt from the booklet you can also read that you would need a lot more counterweights with the original con rods.

Rudolf
Last edited by rschurr on Mon Jan 18, 2021 9:57 am, edited 1 time in total.
1923 James Model 12 500ccm v-twin -- 1960 Chevrolet Corvette C1
1926 Douglas EW 350ccm flat-twin -- 1967 Chevrolet Corvette C2
1936 Motosacoche 500ccm single --- 1979 Chevrolet Corvette C3
1948 BSA A7 500ccm parallel twin -- 1955 Ariel Square Four MKII :!:

allan.walker
Posts: 99
Joined: Fri Sep 28, 2018 8:35 am
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Re: Lockdown: Time for big service, changes and improvements of my SQ4

Postby allan.walker » Mon Jan 18, 2021 8:30 am

rschurr wrote:HI Allen,
The picture with the scales shows a BSA connecting rod as example.
I got a bunch of new AOMCC con rods after one of my old ones got cracked (fatigue fracture ).

And so I got the booklet that I have my knowledge of. In the excerpt from the booklet you can also read that you would need a lot more counterweights with the original conn rods.

Rudolf


Thanks for the clarification, Rudolf. :D


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