M10 Rebuild Project

[Fortlauderdalian]

On 11/1/2023 at 10:27 PM, 2002#3 said:

 

M10 Rebuild Part 18

 

Two 40DCOE's rebuilt.  None to go.

 

 

Have you rebuilt dcoe’s before? Was it difficult and where did you get the rebuild kit from?

Dan

 

 

[2002#3]

Evening, Dan.

 

Nope, not before.  However, I have rebuilt 32/36's recently and am looking for a good 38/38 to rebuild for my M10 rebuild project.

 

Have not installed these DCOE40s yet.  I hope they will work.

 

Not to difficult at all.

• Watch the 3 videos of an expert doing what you are planning to do.  Priceless!  Repeat, priceless!  I can send you the links.  This dude will show exactly how to do it and more, and will show you things I cannot describe. 
• Obtain an exploded diagram of these carbs and a list (usually comes with this diagram) of all >100 parts. 
• Order DCOE40 rebuild kit from alfa1750 on eBay.  THE place for Weber rebuild parts/kits.  In Italy; however, great selection, great prices, and great service.  Shipping time is surprisingly fast.
• Slowly disassemble only one carb.  Remove ALL the parts you can, even all jets.  
• Disassemble the emulsion tubes, pump apparatuses, choke jets, etc.
• I did not bother to remove the butterfly return spring mechanism - too much trouble.
• Lay out the parts in a symmetrical order and visually somewhat like they were removed and where they will not roll away onto the floor and stay put for a while.
• Some of the parts are really tiny and fit together as a team.  Put them onto tape to keep them together.
• IMPORTANT:  Do not remove the shafts and butterflies if they are tight and OK, i.e., unless you HAVE to do so.
• I soda blasted the cases and cleaned them extensively.
• Clean all the reusable parts, i.e., most of them, extensively.
• Reassemble.
• not shown:  the exterior choke mechanisms

The photos below will help you understand what I stated above.  

 

About all I know.  Let me know if I can help more.

 

Larry

Edited December 8, 2023 by 2002#3

[2002#3]

M10 Rebuild Part 20

 

Trial assembly continues.  Head and block partially assembled in order to degree the cam (next Tuesday). 

 

Note to Self:  During final assembly, make sure the circlips are inside the black "cup" washers!

 

 

 

 

[Joesprocket]

I'm intrigued by the round plate that looks like you're using to degree the cam as stated above. Can you tell us (me) how it works?

[2002#3]

Joe,

 

I did this for the first time today.  FAQers are encouraged to correct any errors, clarify confusion, and add suggestions.  Photo of a deck stop was borrowed from the ethernet and is not my engine - a V8 or some such contraption.  Works for an M10.

 

From my memory...

1.  The 360-degree wheel is attached securely with a nut to the crankshaft.

2.  A pointer if fabricated from shop wire, attached with a bolt to the block, and bent to point to the degree marks on the wheel.

3.  A piston hard stop (like the one in the photo) is attached securely to the block.  The center screw is set to touch the highest point of the piston and stop the piston 1/8" to 1/4" (a good guess) from the top of the deck.  Photo was borrowed from the ethernet and is NOT my engine - maybe a V8 or some such contraption.

4.  The crank is turned CW around until the piston just touches the stop screw (obviously short of TDC) and the degree at the pointer is recorded Example:  15 degrees.

5.  The crank is turned CCW around until the piston just touches the stop screw (obviously short ot TDC) and the degree at the pointer is recorded.  Example:  19 degrees.  

6.  Repeat and rinse...just to make sure your measurements are correct.

7.  Halfway between the two measurements (the average) is actual TDC, i.e., 17 degrees.

8.  Move the crank so the pointer indicates 17 degrees.  Now you know where TDC is:  17 degrees...according to the dial.

9.  At this point (for simplicity) you can loosen the crank nut, gently rotate the dial so the pointer indicates 0 degrees, and gently tighten the crank nut.   Now you know where TDC is:  0 degrees..according to the dial.

10.  DO NOT touch the wire pointer from this point until cam timing is complete.

11.  Now you can degree the cam.

 

I hope I got that right...

 

[OldRoller]

11 hours ago, 2002#3 said:

I hope I got that right...

Yes, close enough. I always used a dial indicator on the center of the piston for crank TDC. Now you can do the cam per the spec sheet. Interested in the total meat cut from the deck and head? 

[2002#3]

Deck 0.004”

Head 0.012-0.015”

Edited January 19 by 2002#3

[MurphinDC]

Curious, what's behind the dial?  Just a piece of 3/4 ID steel tube?

 

I've been looking for a crankshaft socket that allows you to attach the dial, but can't seem to find one that is small enough for our M20 crank screw.  Figured I needed to make one.

Thanks!

 

Murph

[2002#3]

Murph,

 

It's an ad hoc  fabricated extension to move the dial away from the TC cover and prevent the dial from scraping against the yellow TDC indicator and the bolt sticking out from the TC cover.  The extension has threads (i) on its anterior end where it receives the dial and the CS nut and (ii) in its posterior end where it screws onto the CS.

 

Hope this info helps.

 

Larry

 

[OldRoller]

Likely to be fine with stock cam timing with less than 0.020 thou total, but your degreeing of the cam will tell the tale. What adjustable cam gear setup are you considering? Cheers, the powerplant is looking nice!

[2002#3]

Standard cam gear machined to have (i) bolt holes shaped into slots and (ii) a newly located locator pin/dowel.  Thanks for asking.

[2002#3]

M10 Rebuild Part 21

 

Degreed the cam today.  The stock cam gear was machined to be adjustable by my machinist.  After the photo was taken, a new cam gear locating pin was fabricated and placed into a new location (~4:00).  Lock washers, LocTite, and safety wire should make for a secure gear.  The valves clear the pistons and all seems in order.  Trial assembly is finished and all has been disassembled.  Next:  Clean all components ad nauseam. 

 

 

[2002#3]

Is safety wiring the above four cam gear bolts really necessary?

[jimk]

Is the head sitting on a head gasket?  If not, degree of cam changes when one is under and the head sits higher.

Had a friend call it, "Precision without accuracy"

[2002#3]

Yep, on a head gasket.