1600 twin Port Running Rough
scm048 - July 3rd, 2016 at 03:28 PM
Hi All,
Pulling my hair out all weekend trying to get my 74 L Bug running right. Recently had the top end of the engine rebuilt by a local (Central Coast NSW)
VW mechanic. Car had a flat spot so took it back to same mechanic who cleaned up, adjusted and put through a carby kit.
It's the original 1600 dual port with Solex 34Pict3 carb. All stock standard other than Vintage Speed exhaust.
Car ran fine when I picked it up, and runs fine when warm (after about 15 - 20 minutes), but runs like a pig when cold and won't idle.
So I have checked all the carb settings, auto choke, cleaned jet, adjusted mixture to factory setting as per Bentley manual, and if anything it's
running worse.
Still won't idle, coughs and splutters and runs rough under load when cold (feels like going to stall).
Any suggestions before I take it back to the mechanic for the 3rd time?
Would have thought after several thousand dollars the car would run right....
adlbeetle66 - July 3rd, 2016 at 04:01 PM
Have you done the basics?
Plugs, points, valves?
splitbus - July 3rd, 2016 at 04:09 PM
Have you got a vacuum leak there somewhere
scm048 - July 3rd, 2016 at 05:22 PM
Plugs, points, valves all done during top end rebuild 3 weeks ago. Possibly a vacuum leak. Driving me nuts!
sander288 - July 3rd, 2016 at 05:51 PM
manifold pre-heat clogged?
Check manifold when just started, it will probably be icy, and after 20 mins check again and see if its warm, this can cause stupid issues.
Fix are to clean out the pre-heats or new manifold
Let us know how you go....
scm048 - July 3rd, 2016 at 07:19 PM
Thanks Sander288, will check that out in the morning.
Bizarre - July 3rd, 2016 at 07:52 PM
Choke sticking?
modnrod - July 3rd, 2016 at 08:12 PM
| Quote: |
Originally
posted by scm048
Would have thought after several thousand dollars the car would run right...
|
Uhhmmm, shit yeah.
Just to add another thing to check, these symptoms sound a lot like a coil losing power, almost to a tee, that's the first thing I'd check
personally.
At least a new one of those won't cost half an arm and a leg.
coletrickle - July 3rd, 2016 at 10:04 PM
X2 for coil.
psimitar - July 3rd, 2016 at 10:53 PM
Was it running OK b4 the top end re-build? Was it reconditioned heads that they did?
If he used those shitty metal gaskets on the inlet manifold or didn't replace the rubber unions on the inlet manifold then those would be worth
checking.
Normally coils get worse once running for a while as they heat up so I'd be looking for a inlet leak or even an exhaust leak cos I bet you he
wouldn't have checked if the exhaust flanges were flat before re-installing.
scm048 - July 5th, 2016 at 07:27 PM
Hi All,
I have a sneaking suspicion it may be a combo of several of the above. Choke has never worked properly, and the engine is hunting.
It needed the top end rebuild as one of the heads was cracked.
Have booked it into another mechanic this Friday who I know works regularly on a Splitty. Fingers crossed he can diagnose the problem/s.
Bizarre - July 5th, 2016 at 07:57 PM
"and the engine is hunting"
That to me is an air leak
scm048 - July 8th, 2016 at 05:50 PM
Update - local mechanic checked her over, and advised whoever re-built the carb made a mess of it. Float levels wrong, screwed together too tightly
for choke to work, and there appears to be some aluminium can used to bodge it up. So much for my local 'VW Expert mechanic'. Think I'll trailer it
to VVDS and get it fixed properly. Might even kick the tin and upgrade to dual carbs.....
The good news is my local mechanic didn't charge a cent. In his words "I couldn't fix it, beyond my speciality so I won't charge you".
Thanks for your advice everyone.
psimitar - July 8th, 2016 at 08:45 PM
| Quote: |
Originally
posted by scm048
Update - local mechanic checked her over, and advised whoever re-built the carb made a mess of it. Float levels wrong, screwed together too tightly
for choke to work, and there appears to be some aluminium can used to bodge it up. So much for my local 'VW Expert mechanic'. Think I'll trailer it
to VVDS and get it fixed properly. Might even kick the tin and upgrade to dual carbs.....
The good news is my local mechanic didn't charge a cent. In his words "I couldn't fix it, beyond my speciality so I won't charge you".
Thanks for your advice everyone.
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Why not give it a crack yourself? Are you not mechanically minded, don't have the tools or lack the confidence?
Just wondering as a carb rebuild is pretty straight forward and rectifying an air leak is pretty easy and requires very basic tools.
Altho, lets hope he actually used a pair of new or reconditioned heads as what you said about the carb doesn't fill me with confidence.
scm048 - July 9th, 2016 at 04:46 PM
| Quote: |
Originally
posted by psimitar
Why not give it a crack yourself? Are you not mechanically minded, don't have the tools or lack the confidence?
Just wondering as a carb rebuild is pretty straight forward and rectifying an air leak is pretty easy and requires very basic tools.
Altho, lets hope he actually used a pair of new or reconditioned heads as what you said about the carb doesn't fill me with confidence.
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Its more a lack of time, and confidence. Happy to tackle simple mechanical tasks but defer to the experts for anything engine related that's more
than a tune up. Also want to get another mechanic to look over the other work already performed on the car just in case. Concerned now about the
quality of that top end rebuild.
psimitar - July 9th, 2016 at 09:34 PM
| Quote: |
Originally
posted by scm048
Its more a lack of time, and confidence. Happy to tackle simple mechanical tasks but defer to the experts for anything engine related that's more
than a tune up. Also want to get another mechanic to look over the other work already performed on the car just in case. Concerned now about the
quality of that top end rebuild.
|
Fair enough dude. I hope the work already done bares up to scrutiny 
sander288 - July 10th, 2016 at 06:38 PM
You won't be disappointed with VVDS
scm048 - July 18th, 2016 at 05:23 PM
| Quote: |
Originally
posted by psimitar
Was it running OK b4 the top end re-build? Was it reconditioned heads that they did?
If he used those shitty metal gaskets on the inlet manifold or didn't replace the rubber unions on the inlet manifold then those would be worth
checking.
Normally coils get worse once running for a while as they heat up so I'd be looking for a inlet leak or even an exhaust leak cos I bet you he
wouldn't have checked if the exhaust flanges were flat before re-installing.
|
You were write psimitar! Got car back today, they were the cheap shitty metal gaskets. Replaced with newbies, idle re-set and she runs like a champ!
adlbeetle66 - July 18th, 2016 at 07:52 PM
Good to hear you got it sorted 
