1600 twin Port Running Rough

scm048 Commited Dubber

59 posts · joined May 2015 · 3 Jul 2016, 3:28 pm

#1027796

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 Under the car.........again!

1,476 posts · joined Aug 2014 · 3 Jul 2016, 4:01 pm

#1027797

Have you done the basics?
Plugs, points, valves?

splitbus Seriously Crusin Dubber

162 posts · joined Jan 2009 · 3 Jul 2016, 4:09 pm

#1027798

Have you got a vacuum leak there somewhere

Cheers, Mike
------------------------------------
| o*/o | 55 split screen
I don't have a bucket list, I have a f^%k it list a mile long

scm048 Commited Dubber

59 posts · joined May 2015 · 3 Jul 2016, 5:22 pm

#1027799

Plugs, points, valves all done during top end rebuild 3 weeks ago. Possibly a vacuum leak. Driving me nuts!

sander288 "Bolt-on Master"

1,404 posts · joined Aug 2008 · 3 Jul 2016, 5:51 pm

#1027803

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....

BMW R65 LS
1967 1300 Deluxe
Swing-axles FTW ❗

scm048 Commited Dubber

59 posts · joined May 2015 · 3 Jul 2016, 7:19 pm

#1027807

Thanks Sander288, will check that out in the morning.

Bizarre Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 3 Jul 2016, 7:52 pm

#1027810

Choke sticking?

Futue te ipsum!!!

modnrod Fahrvergnugen

978 posts · joined Mar 2011 · 3 Jul 2016, 8:12 pm

#1027811

scm048 wrote: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 Wolfsburg Wizard

661 posts · joined Apr 2009 · 3 Jul 2016, 10:04 pm

#1027818

X2 for coil.

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 · 3 Jul 2016, 10:53 pm

#1027819

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.

madness is in the eye of the beholder 👍

scm048 Commited Dubber

59 posts · joined May 2015 · 5 Jul 2016, 7:27 pm

#1027870

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 Moderator The artist formerly known as blue74l

12,789 posts · joined Aug 2002 · 5 Jul 2016, 7:57 pm

#1027873

"and the engine is hunting"

That to me is an air leak

Futue te ipsum!!!

scm048 Commited Dubber

59 posts · joined May 2015 · 8 Jul 2016, 5:50 pm

#1027932

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 Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 · 8 Jul 2016, 8:45 pm

#1027935

scm048 wrote: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.

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.

madness is in the eye of the beholder 👍

scm048 Commited Dubber

59 posts · joined May 2015 · 9 Jul 2016, 4:46 pm

#1027946

psimitar wrote: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.

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 Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 · 9 Jul 2016, 9:34 pm

#1027957

scm048 wrote: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 🙂

madness is in the eye of the beholder 👍

sander288 "Bolt-on Master"

1,404 posts · joined Aug 2008 · 10 Jul 2016, 6:38 pm

#1027981

You won't be disappointed with VVDS

BMW R65 LS
1967 1300 Deluxe
Swing-axles FTW ❗

scm048 Commited Dubber

59 posts · joined May 2015 · 18 Jul 2016, 5:23 pm

#1028218

psimitar wrote: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 Under the car.........again!

1,476 posts · joined Aug 2014 · 18 Jul 2016, 7:52 pm

#1028221

Good to hear you got it sorted 👍