Difference between revisions of "Rebuilding Carburetors"

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(Where are the plugs?)
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= Background =
 
= Background =
  
A standard carb overhaul would replace all gaskets, O-rings, and the float valve/seat.
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A standard carb overhaul would replace all gaskets, O-rings, and the float valve/seat. There are also several drilled passages that are sealed off with lead bits. These are candidates cleaning during a deep overhaul.
  
 
Consider taking this opportunity to replace the old valve/seat with a Grose-Jet from John Titus.
 
Consider taking this opportunity to replace the old valve/seat with a Grose-Jet from John Titus.
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 +
Photos of the carbs and related materials:
 +
 +
http://groups.yahoo.com/group/Sport-Maserati-L/photos/album/1598959955/pic/list
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= Can the passages be cleaned? =
 
= Can the passages be cleaned? =
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These passages are hard to clean, and just soaking will likely not remove it all.
 
These passages are hard to clean, and just soaking will likely not remove it all.
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[[Image:SampleDebris.jpg|left|200x200px|thumb|Sample Debris from one passage]]
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= So what are my options? =
 
= So what are my options? =
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= Where are the plugs? =
 
= Where are the plugs? =
  
Seven plugs altogether:
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== Seven plugs of note ==
  
 
[[Image:OnePlugNearAccelPump.jpg|left|200x200px|thumb|One plug near accelerator pump]]
 
[[Image:OnePlugNearAccelPump.jpg|left|200x200px|thumb|One plug near accelerator pump]]
 
[[Image:OnePlugNearFloatBowlToRemove.jpg|left|200x200px|thumb|One plug near float bowl]]
 
[[Image:OnePlugNearFloatBowlToRemove.jpg|left|200x200px|thumb|One plug near float bowl]]
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<br clear="all" />
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[[Image:ThreePlugsToRemove.jpg|left|200x200px|thumb|Three plugs between barrels]]
 
[[Image:ThreePlugsToRemove.jpg|left|200x200px|thumb|Three plugs between barrels]]
[[Image:TwoPlugsToRemove.jpg|left|200x200px|thumb|Two plugs below float bowl]]
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[[Image:TwoPlugsToRemove.jpg|left|200x200px|thumb|Two plugs below float bowl and two plugs into the float bowl]]
  
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Note that the lower plugs of these two are a front-to-back passage that should be ''(gently)'' cleared out. You will need to approach from the
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front to resistance and from the back to resistance as the passage in
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not perfectly line-drilled.
  
 
<br clear="all" />
 
<br clear="all" />
  
The two into the float bowl can be replaced too for completeness.
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== Two plugs into float bowl ==
 
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The two into the float bowl can be replaced too for completeness, but don't seem to be as likely to cause problems.
= New Plugs =
 
I cut 4mm long pieces of 1/8" (3.175mm) diameter "Bridgit" a low
 
  
temperature non lead solder for copper pipe fittings.  It is made by
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= Cleaning out the passages =
  
J.W. Harris Co. Cincinnati, Ohio.  It contains Antimony, Tin, Silver,
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Used a #36 drill in
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'''fingers only)''' to ream out the passage.  
  
Copper, and Nickel.  It comes in a 1 pound roll.
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''(Need to confirm drill bit size)'' [[User:Brucem|Brucem]] 22:58, 2 October 2009 (UTC)
  
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= Plugging the holes =
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Two methods - Lead bits or tapping for bolts
  
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== New Lead Bits ==
  
http://www.harrisproductsgroup.com/consumables/msds.asp  Scroll down
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One option: 4mm long pieces of 1/8" (3.175mm) diameter "Stay-Safe Bridgit", which is a low-temperature lead-free solder for copper pipe fittings.  It is made by [http://www.harrisproductsgroup.com J.W. Harris Co. Cincinnati, Ohio].  It contains Antimony, Tin, Silver, Copper, and Nickel.  It comes in a 1 pound roll. Specification: [http://www.harrisproductsgroup.com/pdf/spec/Solder/HARRIS_STAY_SAFE_BRIDGIT_LEAD_FREE_SOLDER.pdf Bridgit spec]
  
to Solder and the last item, Stay-Safe Bridgit.
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# Put a drop of Loc-tite (red) in
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# Tap the plug in with a flat punch slightly larger than the hole
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# Cover with a dab of Epoxy Steel J-B Weld.
  
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=== Alternate lead bits ===
  
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Consider [http://www.walmart.com/catalog/product.do?product_id=9222900 Crossman .177cal pointed lead pellets]
  
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== Bolts as threaded plugs ==
  
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Tap the holes for 4mm brass bolts. Use a washer, of course. Holes into float bowl can be bolt-and-nut rather than tapped. Put a bit of red Loc-tite on the bolts.
  
Then tapped the plugs in with a flat punch, slightly larger than the
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This (threaded plugs) makes future rebuilds easier.
 
 
hole. then put a drop of penetrating Loctite (green) on each one then
 
 
 
covered with a dab of Epoxy Steel J-B Weld.
 
 
 
 
 
Nothing wrong with RED Loctite if you applied it to the plug before
 
 
 
you tap it in.  My idea of Loctite came after I had the plugs in and
 
 
 
I used the GREEN penetrating to have it seep in as best it could.
 
 
 
The J-B Weld is the really holding material to prevent the plug from
 
 
 
falling out if it gets loose.  Also you can periodically inspect all
 
 
 
the plugs with a mirror later and insure the J-B Weld is in place.
 
 
 
 
 
 
 
Mike, Any suitable soft plug will work.  I wouldn't use a steel ball
 
 
 
as it would have to be sized exactly and even then it might crack the
 
 
 
housing if it was the least bit too big!
 
 
 
 
 
 
 
 
 
I do the same, put tread on it, easy to clean the DCNF in the future
 
 
 
  only the 2 in the petrolchamber this 2 are welded.
 
 
 
 
 
 
 
 
 
The lower 7 plugs are usually the only ones that need to be removed
 
 
 
and checked for clear passages.  The 2 in the float bowl are not
 
 
 
counted in the 7 to be removed.
 
 
 
 
 
I use brass bolds ( metric 4 mm ) with locktide, the bolds so much as possible
 
 
 
on the DCNF, in the floating chamber you can also use bolds and nuts with
 
 
 
locktide
 
 
 
http://www.walmart.com/catalog/product.do?product_id=9222900
 
 
 
 
 
 
 
 
 
http://groups.yahoo.com/group/Sport-Maserati-L/photos/album/1598959955/pic/list
 

Revision as of 22:58, 2 October 2009

Background

A standard carb overhaul would replace all gaskets, O-rings, and the float valve/seat. There are also several drilled passages that are sealed off with lead bits. These are candidates cleaning during a deep overhaul.

Consider taking this opportunity to replace the old valve/seat with a Grose-Jet from John Titus.

Photos of the carbs and related materials:

http://groups.yahoo.com/group/Sport-Maserati-L/photos/album/1598959955/pic/list


Can the passages be cleaned?

Like most carburetors there are passages (for drilling) that have lead plugs in them.

These plugs can loosen and fall out! leading to Danger

It seems to be primarily age-based, but it's not deterministic. Probably the less time running, the more likely.

But note that even if they are not loose, the passages may have accumulated debris that is very hard to remove.


These passages are hard to clean, and just soaking will likely not remove it all.

Sample Debris from one passage


So what are my options?

The plugs can be removed, the passages cleaned, and either plugs or screws reinserted.


Where are the plugs?

Seven plugs of note

One plug near accelerator pump
One plug near float bowl


Three plugs between barrels
Two plugs below float bowl and two plugs into the float bowl

Note that the lower plugs of these two are a front-to-back passage that should be (gently) cleared out. You will need to approach from the front to resistance and from the back to resistance as the passage in not perfectly line-drilled.


Two plugs into float bowl

The two into the float bowl can be replaced too for completeness, but don't seem to be as likely to cause problems.

Cleaning out the passages

Used a #36 drill in fingers only) to ream out the passage.

(Need to confirm drill bit size) Brucem 22:58, 2 October 2009 (UTC)

Plugging the holes

Two methods - Lead bits or tapping for bolts

New Lead Bits

One option: 4mm long pieces of 1/8" (3.175mm) diameter "Stay-Safe Bridgit", which is a low-temperature lead-free solder for copper pipe fittings. It is made by J.W. Harris Co. Cincinnati, Ohio. It contains Antimony, Tin, Silver, Copper, and Nickel. It comes in a 1 pound roll. Specification: Bridgit spec

  1. Put a drop of Loc-tite (red) in
  2. Tap the plug in with a flat punch slightly larger than the hole
  3. Cover with a dab of Epoxy Steel J-B Weld.

Alternate lead bits

Consider Crossman .177cal pointed lead pellets

Bolts as threaded plugs

Tap the holes for 4mm brass bolts. Use a washer, of course. Holes into float bowl can be bolt-and-nut rather than tapped. Put a bit of red Loc-tite on the bolts.

This (threaded plugs) makes future rebuilds easier.