Sputtering at high RPM

If the problem is above 3500 you are not on the idle circuit, you'd be on the main jets.

Your problem is most likely not fuel, but check the intake manifold to head connection for looseness. Also, check the main jet stacks for looseness. It's almost impossible for a main jet to clog, but you should blow them out for sure. Remember, brass into aluminum, so don't make them too tight.

So, that leaves ignition as the problem.  Cap, rotor, wires, plugs. Pertronix modules go bad with no warning and can definitely exhibit this behavior. Is it possible the distributor got rotated a little(maybe wasn't 100% tight) and timing is off?

Danny

I checked my timing at is still good with max advance a around 26 to 28.  I have the CB performance Magna Spark 2 that is less than 2 years old.  I wanted to rule out the plug wire if I some how I damaged it.  I had a spare set of CB Performance wires and took #3 and replaced it.  Still sputting at full throttle around 4 RMP.  I am going to check my value lashes this afternoon to when the car cools down to make sure the intake isn't too tight.   I will also take a look a the manafold intake to make sure nothing is loose as you recommended.  It is just strange that this starting happening just after I was screwing around with that CHT gauge.

DannyP posted:

If the problem is above 3500 you are not on the idle circuit, you'd be on the main jets.

Your problem is most likely not fuel, but check the intake manifold to head connection for looseness. Also, check the main jet stacks for looseness. It's almost impossible for a main jet to clog, but you should blow them out for sure. Remember, brass into aluminum, so don't make them too tight.

So, that leaves ignition as the problem.  Cap, rotor, wires, plugs. Pertronix modules go bad with no warning and can definitely exhibit this behavior. Is it possible the distributor got rotated a little (maybe wasn't 100% tight) and timing is off?

 This is another good example why the members of this forum are so valuable and very much appreciated:

Like Bob, I've also noticed some similar but very minor sputtering from my 2110cc engine above 3500 RPM.  However, in thanks to Dan's suggestions, we have a few clues as to what may be causing the problem. 

I'm having this exact SAME problem with my car. 

I went through the carbs. No luck. Stan and a few others suggested the module in the Magnaspark II. I purchased a new module. We will see what happens when I change it out.

TRP

I actual have two Magna Spark ingintions.  The first one was on 1914.  When I built my current 2176, I purchase a new one. Well the new Coil I purchased with the Magna Spark was bad.  They sent me a new one and it seems to be ok.  The car was running like a champ and kicked ass.  Ever since I started screwing around with CHT gauge and sensor, the car has not run right.  I don't know If I messed something up while working it.  All I have messed with is the senor ring that goes under the spark plug on #3 cylinder.

Humm... I purchased a new coil too. I'm going to go through the system this week. 

Let me know what you find.

Ted

Ted,

If you have an old coil try swapping it out and see if it makes a difference.  I can't remember what exactly mine was doing last year to make me get a new one.  

Oh yeah, I did forget to mention possible coil. Is the cap on straight/tight? I have zero experience with Magna Spark so I may be reaching here.

Cliff: Thanks.

Later Magna Spark disti caps should have HEI snap-on caps.  Either they’re snapped on or they’re not.

My first impression is that you’ve swapped out the plug and wire for #3 cylinder and nothing has changed, so it is not a problem with #3 cylinder.  And since you haven’t been doing anything out of the ordinary, I doubt that your valves are out of adjustment - Possible, of course, but I doubt it.  

Get it idling nicely and then pull the plug wires off at the disti cap, one at a time, to see if one is different from the others.  Each, when pulled, should cause it to stumble about equally.  If one acts differently from the others, I would suspect that one.

Also, I don’t fully understand your term “stumbling”.  Does it cough/pop back through the carbs, or pop/backfire through the exhaust, or simply run roughly only at high speeds?  Those all point at different things to look at.  My first look at high speed roughness would be if all the main jets are seated properly (I think Dan mentioned that, too).  

My money would still be with Dan, though, that it sounds like ignition.  I would start by looking at plug #4 and go from there.

Gordon

Go advise.  When I get a good break here at work, I will try a few of the suggestions.  I will get back to you all.  Thanks.

Check the firing order. I know it's really basic but it is possible 3 and 4 got swapped, or even 1 and 2. If a pair of cylinders got wires swapped it will do EXACTLY what you're experiencing. Ask me how I know (ROCKY did it) !

1,4,3,2.......

Update.  I had an appointment to have the wheels balanced with an alignment at Auto Assets in Powell, Ohio.   I asked them to look into the sputtering issue.  Later, I talked to the mechanic and he found one of the air bleed screws on passenger side had somehow vibrated out and fallen to the tins.  That was creating a big vacuum leak.  I would have never caught that as you cannot really see the sides of the carbs in the car. Hopefully the car will be ready today. I will post the final results when we get the car back.

Glad it was found. That's an argument for always carrying an inspection mirror to see into those difficult to view spots.

Well, that's the first time I've heard of a by-pass screw falling out.  Sometimes, when you sync the carb throats, you don't even touch some of the screws!  That's a really tough one to find, too, out of sight on the "dark side" of everything.  You're both lucky it was sitting on the tins.

Another crisis averted!  Now you can get out there and drive it for the rest of the summer.

Brass-thingie, 2.0

Just stopped by the shop to see how the car is going.  They finished up the alignment this morning.  The mechanic discovered something else.  The back wheels are off alignment Toe.  There are no toe adjustments on the rear.  He has concluded that mounts for axles where not aligned properly when they were welded to the frame.  So the car dog legs down the road.   Looks like I am going to have to do some surgery on it this winter.  What a pain in the butt!  If you guys recall this is a Beck that was assembled by company out in Colorado.  I can't see Beck making a mistake like this one.  I am sure they use jigs for all their welding.  

Bobby D posted:

The back wheels are off alignment Toe.  There are no toe adjustments on the rear.  He has concluded that mounts for axles where not aligned properly when they were welded to the frame.  So the car dog legs down the road.  

How far of is the alignment? Swing axle or IRS?  

On my swing axle spring plates are slotted or oval in shape to allow for minor adjustments. 

There is a toe adjustment for the rear, he just doesn’t know where to look.

On the spring plate arms, there are two bolts (on each side). These bolts join two half plates to form a single “spring plate” (consisting of the two halves). The holes are slotted, which allows movement fore and aft, effectively lengthening and shortening the spring plate.

Loosening them and sliding back-and-forth is your toe adjustment.  Take it back, and show him what needs to be done.

Then start shopping for a new mechanic. 

If the Rear toe isn't too far off, there is some adjustment available back there:

http://www.vw-resource.com/rea...spension.html#adjust

Scroll down to: 

Rear Suspension Alignment/Adjustment

I fixed a badly mis-aligned Dune Buggy (swing arm) with wedge shims and got an extra 1/4 degree on one side (which was easier than straightening a bent torsion tube).

Good luck!

Stan

I just called the guy again, and he said he would look.  But that he did not see any slotts that could be adjusted.  He is going to look again.  I am not sure if it is the same on a Beck as a VW chasis.

Does the Beck use different spring plates / torsion bars in the rear?  I've never crawled under a Beck to know the answer.  You guys and your fancy toys.

The slots aren't visible because the bolts cover the slots. On my car there are three oval shaped holes which allow the toe in to be adjusted.

I just spoke to Carey at Beck.  He said exactly what you said Stan.  He offered to speak to the mechanic and work him through the process

And who's the MVP this week?  Stan, again?? slotted holes on swing arm, has to be it.

Did I miss where the Brass Thingy 2.0 was in fact the fix for high end stumble?  Sure sounds like a wrong thing to have that hole wide open.  i suppose you'd put it back, screw it down closed, make sure jamb nut is tight, and reset the idle air adjustment. Also make sure the other three jamb nuts are tight, just sayin' . . .

I had a similar issue in my Beck.  The spring plates have three oval holes for the bolts that hold the axles to them.  They should allow enough fore-aft movement to set the toe properly.  If not (as in my case) you may need to extend the ovals in the correct direction.  One thing to note, the early Beck cars were assembled in Brazil, and their quality, while good, was not up to that of the cars built in Bremen when they moved production to the states (one of the reasons they did it).  My chassis was built in late '05 or early '06.

Auto Assets is an upscale used dealership with a good reputation.  They work on a LOT of Porsches.

Oh, just got the car back.  Not very happy.  The mechanic says there is no way to fix the toe issue on the rear without bending something.  I told him everything you guys said he said no way.  Also, the car was popping through the exhaust at Idle and stalled a few time while at sitting at a light on my why home.  Also, when I give it full throttle it is still sputtering at high RPM.  The were going to charge me $1,100 buck.  The owner took it down to $750.    I am going to do a value adjustment tomorrow and see if that helps.  Attached is the print out of alignment.  What are your thoughts? 

Contact Carey Hines (@chines1) and if it’s similar to the problem I had it CAN be fixed.  Carey fabricated a slightly longer spring plate for one side of my car and I swapped it out.  The other side was machined to fit.  Unless someone bent the frame it IS fixable.

Where are you located, Bobby?  You probably already looked into s local SOC member helping out, but that might be the best best.  Don’t despair just yet.

I am in Columbus Ohio

Lane, what is your serial number (stamped plate #) with the date from '06?

I have #179 with a stamped plate of 2010.

I believe mine sat as an unfinished roller for a few years.

I am also going to check my fuel filter and pressure to see if there is some restriction in the line.  

Bobby D posted:

The were going to charge me $1,100 buck.  The owner took it down to $750.    I am going to do a value adjustment tomorrow and see if that helps.  Attached is the print out of alignment.  What are your thoughts? 

Thoughts? He's an idiot and a thief.

Jack the car up, and you'll see what we're all talking about. The spring-plates have slots in them. It's possible the slots need to be elongated, but we're not building a rocket in the basement here.

It's mid-summer, and you're losing driving time. Carey is only 4 hrs away. Trailer the car up to him, and it'll be done by somebody who is neither an idiot nor a thief, and for probably substantially less than $750.

Listen to Stan.

Stan,

I just might have to do that.  I want to get the engine thing figured out first.

Did the "mechanic" ever speak with Carey?

Bobby, my car is #184, but was completed in June 2006, so while was manufactured shortly after yours it was finished years before.  Yours is definitely a Brazilian car.  I wonder if they had an issue with their jig that caused the rear torsion bar housing to be offset slightly.  Regardless, Stan’s suggestion is spot on.  Carey can get it straightened out.

Bobby D posted:

 

...The mechanic says there is no way to fix the toe issue on the rear without bending something...

...Also, the car was popping through the exhaust at Idle and stalled a few time while at sitting at a light...

...The were going to charge me $1,100 buck... 

As Monty Python might say, run away!

When my VS was new, I took it to a local 'Air-cooled VW shop' to fix a few sundry issues, including an engine that popped and coughed and died at inconvenient times. After two weeks and $1200, things hadn't improved much.

Any decent mechanic who really knows these cars should have the carbs and ignition whipped into shape pretty quick or not charge you much if they're really baffled. But decent mechanics aren't often baffled. My carbs just needed some basic setup and that shop's 'carb expert' was just plain clueless.

And the rear toe on my car was also a little too far out to be dialed back in with a simple adjustment. We elongated one of the slots and that was that. Of course, that meant pulling one of the spring plates and having to fuss with the torsion bars on that side when putting it back together.

Find a mechanic who doesn't mind getting his hands dirty.

Bobby D posted:

Stan

I just called the guy again, and he said he would look.  But that he did not see any slotts that could be adjusted.  He is going to look again.  I am not sure if it is the same on a Beck as a VW chasis.

@Bobby D

For visual reference, here is a pic of the spring plate and the elongated holes. This is basic VW knowledge that escapes the mechanic you talked with.

The holes are usually covered by the axle attachment bolts.

Jim 

Thank you for the picture.  I am going to give it a shot myself.

Lane 

Our car was built in 2013