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914World.com _ 914World Garage _ A Question for the /6 guys.

Posted by: Headrage Nov 20 2005, 08:15 PM

I have a new(?) /6.. 2.7 w/big 46mm carbs. Couple of pumps on the gas and vrooom. Let it sit there and idle and it's mmmmnmm pop mmmm pop pop mmmmmmmmmm pop mmmmmm pop pop w/little black spots ending up on my driveway.

The wife hates it...

Head/Cylinder leak???

Posted by: SLITS Nov 20 2005, 08:21 PM

black spots under the engine

or

black spots where the exhaust exits?

Posted by: Headrage Nov 20 2005, 08:24 PM

QUOTE (SLITS @ Nov 20 2005, 06:21 PM)
black spots under the engine

or

black spots where the exhaust exits?

Black spots where it is shooting out of the exhaust...

Posted by: sixnotfour Nov 20 2005, 08:27 PM

Have you went to the pmo info site , faxed richard , you need smaller everything, document your jet and venturi sizes first.
Wife Hates is a bad sign. Carbs are not for everyone. http://www.pmocarb.com/support.htm
Better hope its not a head leak, probably popping out the exhaust due to over rich condition
Good Luck

Posted by: Headrage Nov 20 2005, 08:32 PM

I've checked into the PMO carbs but that's not the problem.. The carbs I have are just too plain big...

The concern I have is the sound I get from the exhaust Possible exhaust leak).

I'm gonna figure out a way to digitize the sound and let everyone here it...

Posted by: Headrage Nov 20 2005, 08:33 PM

QUOTE (sixnotfour @ Nov 20 2005, 06:27 PM)
Have you went to the pmo info site , faxed richard , you need smaller everything, document your jet and venturi sizes first.

Yes...

I hear that Richard has become very reclusive...

Posted by: J P Stein Nov 20 2005, 08:36 PM

First thing is that it's not unusual for a cold carbed motor to pop out the stacks or taill pipe. The black marks are also not unusual.....carbon & water from condensation in the headers
Or oil that has leaked past the rings or guides while the motor has sat. The former is OK, the latter is worth looking into. Is it oil or water....clue, one drys up.

If it's popping out both ends, it's probably carb tuning or (less likely) ignition. Out the throats is lean. Out the exhaust is often rich....Need more info....which end?
(edit)
Humm....I type slow
(re edit)
That young fella Slits is even slower

Posted by: sixnotfour Nov 20 2005, 08:36 PM

I was not implying you need PMO's simply that richard could help you jet those thing down so it will run properly ,without buying new carbs or 40's. He is the weber/PMO conversion King.
QUOTE
Yes...

I hear that Richard has become very reclusive...

Oh

Posted by: SLITS Nov 20 2005, 08:36 PM

Allan, as Dan stated in the earlier thread (or someone stated), "S" cammed engines are set to run rich a low speed. If the fuel is not getting burned (rich mixture) fully, it soots up the exhaust. Add water or excess fuel to the soot and wella....black spots on the driveway (and if ya punch it..on the person's legs standing behind the exhaust.

Put yer finger in the spot and see if it just wet soot..

The pop...pop...pop could be the plugs clearing themselves, carbon doing a preignition thingy in the cylinder, unburned fuel igniting in the exhaust piping..

As far as a cylinder leak...if you ever heard a VW going down the street with a pulled head stud, you will never forget that sound.

After your engine is heated up and you've given it a couple of 5K "blow outs"...do you still have black thingys coming out?

While Slits is an asshole, Ron can be a nice guy....I have a set or 40 IDA 3Cs off a '68 T that you could possibly try. It should lean it out a shitpile.

Posted by: trekkor Nov 20 2005, 08:36 PM

You need 40's.

I think people run 40's up to 3.0's

KT

Posted by: sixnotfour Nov 20 2005, 08:40 PM

That motor is an 77 S ,CIS injected, originally . not to be cofused with early more radical S cams.carbs,mfi

Posted by: Headrage Nov 20 2005, 08:41 PM

QUOTE (trekkor @ Nov 20 2005, 06:36 PM)
You need 40's.

I think people run 40's up to 3.0's

KT

Trekkor you got it nailed!!!

I just worry about the freakin weird sounds that I get.

I'm gonna record a sample clip for everyones amusement ...

Posted by: messix Nov 20 2005, 08:46 PM

if i remember right.
dan wasn't able to get ahold of a sycrometer to adjust those carbs. he just tuned it by ear. sounds like the idle needs to be tuned with the sycro.

when he took me for my ride was only the 2nd or 3rd time out with those carbs.

Posted by: sixnotfour Nov 20 2005, 08:48 PM

QUOTE
QUOTE (trekkor @ Nov 20 2005, 06:36 PM)
You need 40's.

I think people run 40's up to 3.0's

KT

Trekkor you got it nailed!!!

I just worry about the freakin weird sounds that I get.

Thought you knew that from Pelican, Should trade with the guy that offered you cash and 40's.

Sorry it was foggy all day up here

If you do get 40.s this should be close
32mm venturi's ,135mains,180aircorrectors,60idles,F3immulsiontubes

Posted by: Dan (Almaden Valley) Nov 20 2005, 08:56 PM

40s are the way to go. I had them on my very robust 2.7L RS motor. Worked great. None of the problems you are reporting.
46s are way too big.

Posted by: Seaside6 Nov 20 2005, 09:17 PM

Dirty jets will steal your engine's joy. Before making any changes I would try removing each of the jets and blowing compressed air through the jets and the throttle body hole the the jets come out of.

My 2.5L short-stroke was running rich and popping like crazy. A friend told me about this compressed air trick. My car immediately ran better but these symptoms would return after a few days. After a couple of months of every few days cleaning I took the fuel tank out and had it cleaned at a radiator shop. I have never had another problem and that was a year ago. My car has run great ever since.

It will take you about 10 minutes to find out if this helps your problem.

Posted by: Headrage Nov 21 2005, 05:49 PM

Just got a call from Richard at PMO. He said that I'll never get 46's to run right on a 2.7 unless it's a race motor running 190+ compression. He recommends going to 40's for optimum tuning.

Posted by: sixnotfour Nov 21 2005, 06:08 PM

That confirms it , you owe some

QUOTE
If you do get 40.s this should be close
32mm venturi's ,135mains,180aircorrectors,60idles,F3immulsiontubes

here is the guy
QUOTE
I guess you don't have PM's set up on your profile. Give me a call or e-mail, I'm interested in trading my 40's plus cash for your 46's.

-Andy Simpkinson
707-449-8774

Posted by: Mike D. Nov 21 2005, 06:39 PM

Ah that sound...mmmmmmmmmpopmmmmpop pop mmmm, I know it well.....
I have a 2.0 6 with 40s, 135s and 55s. I only get poping crusing in the mid range. But I'm running a MSD6al so at idle I've got extra spark to keep from fouling. I sould probably step down all my jets, e tubes, chokes...

Posted by: Eddie914 Nov 21 2005, 08:57 PM

Alan,

46 IDA Webers are a bit big for a 2.7 S CIS engine. I have been running 40 IDA Webers on the same eingine with 32mm venturies as per Richard's (PMO) recommendations and they run great.

Would you like to trade?

Eddie

Posted by: Gint Nov 21 2005, 08:57 PM

I always assumed that sound on my /6 was from the sloppy leaky throttle shaft bushings. Yours OK? I never did get mine resolved before tearing the car apart for resto.

Posted by: Root_Werks Nov 22 2005, 08:56 AM

Those 46's were gone through by Bieker, they are better than they were new. Have needle bearings instead of bushings.

Just my opinion, but I would jet down the 46's you have, toss some 36 vents in there and tune them properly.

I bolted the carbs on, went for a ride and thought, Damn, that fixed a whole mess of shit.

Compression when I checked it was 155-160 across the board. Unlikely your leaking anywhere. I also replaced I think 8-9 exhaust studs, so everything under that should be tight as well. But things can happen and change.

Those 46's are $$$$, don't let them go that easy. You can get them to work just fine on a 2.7.

I did only drive the car 2-3 times after putting those carbs on. So I never tuned or sync'd them better than my ear. But the car would would give a healthy CHIRP into second gear every time full on. It should still be nothing less than an absolute rocket. If it isn't a rocket, something isn't the same. Messix can atest to that.

Posted by: Bleyseng Nov 22 2005, 09:33 AM

QUOTE (Eddie914 @ Nov 21 2005, 07:57 PM)
Alan,

46 IDA Webers are a bit big for a 2.7 S CIS engine. I have been running 40 IDA Webers on the same eingine with 32mm venturies as per Richard's (PMO) recommendations and they run great.

Would you like to trade?

Eddie

Eddie, what happened to that new motor you got? Is it in yet?

Posted by: messix Nov 22 2005, 01:22 PM

come on cali guys. one of you can help him set those up to run smooth as a swiss watch.

Posted by: sixnotfour Nov 22 2005, 01:25 PM

Eddies been in, out, and in pieces, 2 motors worth or pieces.

QUOTE
come on cali guys. one of you can help him set those up to run smooth as a swiss watch.

thats why i suggested he talk to richard at pmo for jetting and venturis.