Help with '64 Spyder will not idle and stalling

[Nickshu]

I need some help from the braintrust here. I have had my ’64 Spyder for 2 months now and I cannot get it to run correctly.

The problem:

The car will start right up when cold. After it runs for a few minutes it starts to act like it’s flooding. It will only idle at 1500-1900RPMs when hot. Any lower and it will sputter and eventually stall. Then it will not restart until it has cooled down/sat for about 10-20 minutes. Then it fires right up and does the same thing all over again. When it does run, once off choke, I can see a lot of fuel coming out of the main nozzle at idle (1100-1900RPM that is). I have a video I will post of the carb. Manifold pressure gauge at idle fluctuates between 15-20 oscillating with RPM (not rapidly) at 1100-1900. When I can drive the car the turbo boost is very weak, maybe +2-4psi tops on the manifold gauge.

What I have done so far:
1.) Set timing (24 degrees) and idle.

2.) Rebuilt my original carb per Bob Helt’s book. Played around with float settings. Made sure needle/seat were working properly- all good. No change.

3.) Installed a Holley 12-804 fuel pressure regulator w/ gauge set to 2-
2.5psi. No change.

4.) Installed a new fuel filter. (Clarks) No change.

5.) Replaced all ignition components with new – Cap/rotor/points/plugs/plug wires/condenser – No change

6.) Compression check – All good. #1=120/#2=130/#3=120/#4=125/#5=115/#6=115 – All good.

7.) Installed a different rebuilt carb from Grant Young. Again played around with float settings (3/4” – 2 3/8”). Made sure needle/seat were working properly- all good. No change.

8.) Made sure fuel return line was clear w/ compressed air. It’s clear.

9.) Blew compressed air thru fuel filter w/ return connected to make sure no blockage in fuel filter. All clear.

10.) Removed fuel pressure regulator (thought it might be faulty). No change.

11.) Sprayed carb cleaner in various places in hopes of finding a vacuum leak. Nothing found but it is tough to spray around the turbo housing.


A very kind and generous forum member has been helping me try to sort this out but we are a bit stumped now. I have had two different carbs and the same behavior. I know fuel pressure and float level is not the issue. Currently thinking that the engine is not drawing enough vacuum to properly atomize fuel resulting in a flooding condition. Interestingly the car seems to run best when choking, once the choke starts to come off is when the symptoms get worse.

At this point we are thinking either a vacuum leak that I have not detected or possibly improper valve adjustment. Does that sound reasonable and what is the likelihood that valve adjustment could play a role here?

Thanks all!

[doctorwire]

Check all, and I mean all, of the intake gaskets. Especially the rubber coupling between the turbo and the intake, and the gaskets at either intake manifold. These turbo engines aren't very forgiving if there is one little vacuum leak.
My rubber coupling looked ok but the car ran like crap until I replaced it.

[Nickshu]

That's good info. I had a hard time spraying carb cleaner around the intake boot. Mine has surface cracks but nothing that appears thru and thru, but certainly possible that it's leaking. Will replace all gaskets/hoses and see what that gets me.

Can you replace the turbo intake side gasket without rebuilding the turbo itself?

[DAVECS1]

Have you checked the vacuum/boost adjuster for the distributor. Make sure it moves normally and that it is not shifting your points or electronic pickup away from the cam or magnet.

The week boost could be the sign of a marginal rubber vacuum/boost connection. It may be getting hard due to age and heat. The boost blows it open and strong vacuum causes an issue. When your at 1100 and above with no load you manifold vacuum is really low, so checking for leaks at that time can be difficult at best.

[Nickshu]

Thanks Dave. The car did have a vacuum advance when I got it. I removed it and replaced it with the proper pressure retard unit, a new hose, and new hose clamps from Clark's. I pulled a vacuum on the pressure retard and found no leak, and I also tried clamping off the hose from the manifold to the pressure retard with no change.

The distributor is actually a 1963 110298 unit, but seems to work fine. I just found a 110314 unit (correct for 1964) and can swap out for that one in the future. I don't think this is spark related but anything is possible at this point.

Have you checked the vacuum/boost adjuster for the distributor. Make sure it moves normally and that it is not shifting your points or electronic pickup away from the cam or magnet.

The week boost could be the sign of a marginal rubber vacuum/boost connection. It may be getting hard due to age and heat. The boost blows it open and strong vacuum causes an issue. When your at 1100 and above with no load you manifold vacuum is really low, so checking for leaks at that time can be difficult at best.

[miniman82]

I can see a lot of fuel coming out of the main nozzle at idle (1100-1900RPM that is).

Your idle circuit is plugged, there should not be any fuel coming from the mains at idle. Also 1100rpm is too high, tweak the idle screw till it slows down.

[Nickshu]

I can see a lot of fuel coming out of the main nozzle at idle (1100-1900RPM that is).

Your idle circuit is plugged, there should not be any fuel coming from the mains at idle. Also 1100rpm is too high, tweak the idle screw till it slows down.

Here's a video (link) of what it looks like down the venturi at idle around 1500.

If I turn the idle screw down it stalls out at anything below 1100-1200, so that won't work.

http://s1273.photobucket.com/user/1964M ... 1.mp4.html

After reading your post I reread Bob Helt's description of the idle circuit, much more clear now how this is supposed to work. Perhaps I have both a vacuum leak and a plugged idle circuit.

[bbodie52]

How are you setting the timing to 24° BTDC with a timing light when the engine is "idling" at 1100-1900 RPM? Wouldn't the distributor centrifugal advance be engaged at that engine speed? If it is your initial timing setting may be off. The timing should be set with a timing light at an idle speed of 850 RPM or static timed with the engine off. To static time an engine, with the distributor cap off rotate the engine so that the timing mark on the pulley is pointing to 24° with the rotor pointing at the cylinder no. 1 distributor cap location. Place a narrow strip of paper between the ignition points with the rubbing block at the low point of the distributor cam, to the left of the cam lobe. Then slowly rotate the distributor base counter-clockwise until the paper is just released by the points contacts opening. This places the static timing very close to 24° BTDC.

You seem to have covered all the bases in your engine checks to try to detect the cause of your engine trouble. Just a wild thought... the compression is good on all cylinders when the engine is cold. Is it possible that a cylinder head valve is sticking open when the engine is hot, as it might if the clearances between the valve and valve guide were tight and became tighter as the valve and guide expanded as they heated up? But if this were occurring I would think that a valve sticking open would create a lot of valve train clatter if the valve stem were not following the rocker and pushrod operation. It is a "wild card" idea, but I'm trying to think of what might cause an inability to idle at normal operating temperatures and why you are experiencing apparent low turbo boost pressures. I would normally think of the choke butterfly valve being stuck closed, but that would be obvious when you have the air cleaner removed and are peering down the carburetor throat.

If you are still chasing a possible vacuum leak, could there be a problem with the long flexible tube connecting the mechanical boost gauge to the intake manifold? If this were leaking it could be the source of a vacuum leak, and would also cause the boost gauge to read low if some boost pressure were leaking between the gauge and the engine. If you suspected such a problem you could temporarily disconnect the boost gauge at the engine connection and block the connection point, to eliminate this possibility.

[Nickshu]

Hi Brad,

I set the timing at one point when I was able to get it to idle at about 900, on my prior carb I was able to get it to idle lower but not well.

The valve thing that you describe is what I am thinking, but I want to investigate the carb further.

Good idea on the manifold pressure gauge line. I will look into it as well.

Will post results....

[miniman82]

Here's a video (link) of what it looks like down the venturi at idle around 1500.

If I turn the idle screw down it stalls out at anything below 1100-1200, so that won't work.

http://s1273.photobucket.com/user/1964M ... 1.mp4.html

After reading your post I reread Bob Helt's description of the idle circuit, much more clear now how this is supposed to work. Perhaps I have both a vacuum leak and a plugged idle circuit.

You clearly have fuel dribbling out of your main venturi, which is not correct if you were at idle. Could be several things wrong, but if it refuses to idle lower than what you're at now my vote is blocked idle circuit.

Here's what's happening: When cold the fuel coming from the mains is richening the mixture, which acts like a choke. As the engine warms up it no longer needs this additional fuel to run, which is why it's a pig when hot. Cool it down, it's fine again. If you can get the idle circuit figured out, the mains won't dribble anymore because you won't be on them, and it should run fine hot or cold. Gotta figure out the plugged idle circuit and stop idling on the mains or you'll never get it right.

[Nickshu]

I think I found the problem. Removed the turbo intake side housing and found a HUGE amount of play in the turbo impeller, also scored on the inside of the intake housing where it's hitting.

I also removed the carb and ran a pipe cleaner and compressed air thru all the circuits....no blockage found on the idle circuit (or any other circuit). I think all that fuel coming out the main was b/c the "idle" was at above 1500RPM, so probably normal for that RPM.

My thought is that it's leaking vacuum thru the turbo shaft due to all the play. Sound plausible?

I am thinking of blocking off the turbo w/ a piece of sheet metal (removing the impeller) with a gasket on each side to make sure this is the issue.

Here's a video of the Turbo impeller:
http://s1273.photobucket.com/user/1964M ... 2.mp4.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[DAVECS1]

I have seen many failing turbos cause this issue. It takes some amount of back pressure to get those to spin, when they get loose it surges back and forth as it gets hung up on the housing. Also when the turn I sticks it spins up a little cause air idle issues. If the turbo is anything like the carbs there should not be much to it for a rebuild. Probably uses bushing, that you can pick up at any bearing distrubutor. Then go down to your auto parts store and get a brake hone. If the shaft is messed up, probably need to go on a bear hunt.

[miniman82]

I think I found the problem. Removed the turbo intake side housing and found a HUGE amount of play in the turbo impeller, also scored on the inside of the intake housing where it's hitting. Here's a video of the Turbo impeller.

Video link is broken, reup?

If the turbo is shite I can rebuild it, I'll send you my address.

If the turbo is anything like the carbs there should not be much to it for a rebuild. Probably uses bushing, that you can pick up at any bearing distributor.

Ummm, no...

The turbo is a precision unit, with specific tolerances. It can be done by the layperson, but not without special tools. You need a feeler gauge, dial indicator and dial micrometer to do it correctly. There are no bushings, but there is an aluminum bearing.

[Nickshu]

[Joe West]

Nick,

I think you are going to be pleased with how your Spyder runs when you get the turbo back from being rebuilt.

Joe

[DAVECS1]

I was not trying to play down the turbo and its rebuilding process sorry if it came a crossed that way. My initial thought was it is not as complicated as today's turbos, with built in waste gates, variable geometry turbines and compressors, and materials that break if you touch them wrong. My look at this was, it is a straight forward turbine and compressor made of all metal alloys, with a center cartridge that contains oil, bearing and seals.

I bet the rebuilt turbo will be a welcome rush of power:-)