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xenon
Samba Member
Joined: September 27, 2014
Posts: 6
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 Posted: Tue Dec 16, 2014 6:23 pm Post subject: Why is my Synchro Meter Doing This |
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Getting the 356 going after some months in storage. Had distributor rebuilt, new igntion parts, fuel pump, 40IDF's rebuilt, etc. etc.
Car starts fine but idles rough. No smoke from exhaust.Dynamic timing is spot on. Checked carb synch and cylinders 1 and 2 are balanced at 4 kg. When I put the synch meter on 3 and 4 the needle bounces wildly from zero to 30 and back. The meter is actually making a loud tapping noise when the red indicator hits the top of the gauge. Never experienced this before.
Any help with this would be really appreciated. |
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MacLeod Willy
Samba Member
Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Tue Dec 16, 2014 8:29 pm Post subject: synch |
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| Do a compression check again. Sounds like an intake valve is tight/not sealing causing it to blow back into the intake |
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xenon
Samba Member
Joined: September 27, 2014
Posts: 6
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| Posted: Tue Dec 16, 2014 10:17 pm Post subject: Re: synch |
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| MacLeod Willy wrote: |
| Do a compression check again. Sounds like an intake valve is tight/not sealing causing it to blow back into the intake |
That makes sense, thank you.
Any good methods to deal with sticky intake valve, short of pulling the engine? |
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dsrtfox
Samba Member
Joined: August 25, 2009
Posts: 443
Location: Phoenix
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| Posted: Tue Dec 16, 2014 11:29 pm Post subject: |
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| Maybe just tight and not sticky... |
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MacLeod Willy
Samba Member
Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Wed Dec 17, 2014 6:49 am Post subject: |
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| dsrtfox wrote: |
| Maybe just tight and not sticky... |
Your right, might be adjusted too tight as well. Either way, pull that cover and inspect things. Could even be a broken spring. If it is sticking, try some Gumout or similar product for carbon cleaning first before tearing things down. |
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xenon
Samba Member
Joined: September 27, 2014
Posts: 6
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| Posted: Wed Dec 17, 2014 5:29 pm Post subject: |
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Thanks for the responses. Cylinder compression on cold engine with slow cranking is 113 psi on Number 1, 120 on number 2, 101 on number 3, and 122 on number 4.
Pulled rocker cover on 3-4 and all valves appear to be functioning normally. Valve lash is unchanged at 6 thou. Held a piece of paper in front of exhaust pipes and getting only positive flow.
Snail gauge on RH Weber is 5 kg and steady. Left carb is at 18. Getting an occasional spit from both sides. Idle adjustment screw on number 3 will not turn either way with fingers.
Number 1 and 2 plugs are tan. Number 4 very light coloring and number 3 pure white.
Rough idle but seems to smooth out at higher rpm's.
Bad carb? What would cause the high vacuum at idle? |
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MacLeod Willy
Samba Member
Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Thu Dec 18, 2014 3:01 pm Post subject: sync |
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| Sounds like a possible vac leak on one cyl. or is #3 screw bottomed out? And maybe the right side idle screw is in more? |
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xenon
Samba Member
Joined: September 27, 2014
Posts: 6
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| Posted: Fri Dec 19, 2014 7:07 pm Post subject: Re: sync |
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| MacLeod Willy wrote: |
| Sounds like a possible vac leak on one cyl. or is #3 screw bottomed out? And maybe the right side idle screw is in more? |
Right on. It was a vacuum leak in the Weber. Replaced all the gaskets from the spacer up and it runs sweet now. Thanks for everyone's help! |
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dsrtfox
Samba Member
Joined: August 25, 2009
Posts: 443
Location: Phoenix
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| Posted: Fri Dec 19, 2014 7:53 pm Post subject: |
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| I've got Weber's on mine too and love them. Never ran as good with 40P 11's. Although the Solex's, all 5 of mine are wore out. $1,600 to repair or Weber's for $500, it wasn't a real hard decision. |
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