So I have been playing around... here is where I am at now!

[Anonymous]

OK, so I started out last week running with some puffs of smoke on the shifts.. and having a rough idle and fast rpm range. I have spent this week driving the car and here is where I am at now.

First I still feel like there is something obvious missing here.
The car idles very rough and I cannot get it any better without adding more timing and rpms.
(I am still trying to get a video camera and record some stuff to post that maybe we could all look and listen too. but that is going slow.. as I have no camera yet.)

Right now... the car
Idles at around 1000-1100 rpms... anything below that is very rough.
Initial timing at that idle is 22 degrees... I was at 25, but backed it down, I am considering going back, as I have lost some pep and it is harder to start here... it really likes the 25 degree mark on the dial back.
My vacume is 14 degrees steady but the needle vibrates, does not fluctuate, just vibrates... this is with 1.5 turns on both idle screws... anything more and nothing happens and it drops the rpms at 1 turn.
Still getting clouds of smoke out the back, I have 125 miles on it now... the plugs are fouled and the pistons have a nice coating of black crap on them, as well as the tail pipes. (This makes me VERY unhappy... I guess the polish job on the pistons is worthless now.... I hope to burn and clean that out once the rings seat, hopefully, and I am considering changing plugs again soon...)

Overall it has a lot of power... tons more than I ever had, the smoke is getting old, and on my nerves... but the sound and the feel is great.
It has never pinged yet.. but I had the timing at 30 degrees at my idle rpm range and it had a noticeable loss of power, and it gave me a little run-on when shut off...

First and second gear are REALLY tight, you have to mow through those really quickly if you want to stay under 3000rpms... I have pushed it once or twice up to 3500 but nothing more yet... there is a definite Power increase over 3000... the engine wakes up in the 3200 range... once the breakin is over I can experiment with the higher ranges... I would also like to get the timing and other things worked out first.

I am just starting to run out of ideas? either this engine wants to run at this range... or I am seriously missing something... I did spray down the intake and carb base with WD40, and other than a lot of smoke, I got no real noticeable changes in the engine idle... I checked and blocked off all of the connections for vacume and found no changes putting them together again... I left one open intentionally and there was a really big difference.. I had trouble keeping it running with one of the intake ports open... I plugged the PCV system and that made no difference at idle either.

I do have the following two things though..
1. I am running a clear plastic fuel filter and at times there is almost no fuel in there... even when running.. a trickle flows through at the bottom but not enough to fill it... then sometimes it is almost full except for a little air bubble at the top?
2. I installed two screws through the intake into the port divider where the thermostatic choke holes were on the original head... we did this to secure the divider and to seal the holes. All of the paint has pealed off around the bolts as well as over to the head bolt on that flange... I put some WD40 down there to see if they were leaking, but nothing I noticed?


This is all I have for now... I am working on making a clutch fork cover... has taken me a week to make this thing... as I could not buy one anywhere, that fit I had to make one... and I am not driving it too much until this is done.

 

[CobraSix]

Just a few ideas. I know they may have been floating already.

Are you running vacuum advance?

I think your initial timing and high RPMs are linked. It is a circle that drove me crazy all spring. set the timing to around 12-15 BTDC. Don't worry about the rough idle for now. Now close the idle mix screws until the RPMS start to drop. Then back out 1/4 turn. Next, make sure the throttle plate screw is completely off. That is what got me for so long on my carb, my throttle plate screw had the throttle plate open just enough to keep the RPMS above 1200RPM. Once you do that, re check timing and repeat the process. With the hotter cam, you will have a slightly rougher idle, especially when cold with no choke (like me). My cars sounds like it harder wants to run, but eventually it smooths out.

Don't know about the smoke. But you can clean your cylinders using the water trick. use a squirt bottle on Spray and with someone playing the throttle, spray a little bit of water into the carb. This is important...BE SURE TO KEEP THE CAR RUNNING, no matter how much gas you need to give it. Repeat a few times and you will see all sorts of crap come out your exhaust. Definitely a 2 person job though.

Slade

 

[Anonymous]

That is one of my thoughts that I may be masking something with the added rpms and timing... I am going to try your test and see what happens.


ADDED:

OK, so I did that... here is what happened.

Dropped the timing to 12BTDC...
RPM to 900
Vacume to 9-12....

the engine idles, rough, but idles...
The timing is right on 12 degrees... at this range.. the engine speed varies... it goes from 850-950 and the vacume varies from 9-12... I gave it some throttle and it drops to zero then spikes to 30 then stops at 9. This is with the vacume lines plugged.

Yes I am running Vacume advance but right now it is plugged and not hooked up.

 

[MustangSix]

The black smoke and fouling tends to be linked to an over rich condition. And the need to have so much initial advance might be related to the same over rich mixture not being able to burn conpletely. You might need to rejet and get a new powervalve.

Pull the float and remove the jets. Note the number and get some that are two numbers smaller. Also look at the Power valve. There will be a number on that as well which indicates the vacuum level that it begins to open. It should be 8 or less, and the right valve might be as small as 6 or even less. It may take some trial and error.

Also make sure the float level is correct and not too high.

You'll have the mains just about right when you can cruise at light throttle with no bucking or surging. And you'll have the PV about right when the car accellerates well at WOT with no surging or flat spots.

 

[Anonymous]

I was really trying not to do that... but I guess I might have to.

I wanted to wait till I get a few thousand on the engine then Dyno it with new jets and possibly a power valve.

But I think you are right... I can cruise with the car but it does have a surge sometimes. and the accel still has a few flat spots.

 

[Anonymous]

I guess the best thing to do is pull the carb and take it apart and go from there.

I think that will be easier than trying this on the engine.
Where can I get those parts? Holley? Summit? or a local shop?

 

[Anonymous]

If your engine doesnt start to wake up until 3000 rpm with the cam youve got I would be suprised if it would like being run in at under 3000rpm. Just a thought ,I could be wrong put I would be looking to run it in up to 1000 rpm up from where it starts making power just enough to keep it above 3 when a gear change is made. You dont have to give it full throttle.

 

[Anonymous]

Might be difficult to optimise correct fuel settings etc for driving under 3000 and above 3000 with your cam (sounds like its not designed to anyway). Do you intend to do most of your driving where it makes its power?

 

[Anonymous]

This cam has an RPM range of 2000-5500 and there is a definite power surge over the 3K mark... I went out again a few moments ago to road test the timing and RPM settings I made earlier and gave it some good throttle in that ballpark... it jumped to 4000 from 3000 like no tomorrow... I just watched the speedometer climb very quickly in that range... below 3000 it has some great low end torque... but the midrange on this cam is fantastic.

On my driveway coming up a 35 percent grade at this timing setting the power surges a lot... it was better at the more advanced timing... again pointing to jet size as the major source of my trouble at the moment.

Another thing...

I have never given it full throttle... not even close all I am doing is light throttle...

 

[Anonymous]

What is your cam duration at 50 degrees. You should have it with your specs for the cam?

 

[Anonymous]

he said drive it like normal, don't baby it, and get out there on the road...

I'd follow your mechanics' advice, you still only have 125 miles on it. Take it on the interstate and vary the speed a little.

Did you do the compression test?

Don't you have the 2300/350? Mine ran great out of the box. I can't choke it at all. I had similar problems to yours with the H/W 5200.

Isn't it odd that no matter how much advance you give it there is no pinging, what is it all in?

Are you getting 12v to the coil?

That's all I can think of.

Luck,
don

 

[Anonymous]

Schneider Racing Cam:
260/270, 208/214@ 0.50, .420/.440 lift 110° lobe centers.
CR = 10:1


I am going to Drive it even though it might not be 100%
I finally got that Clutch Lever Cover fitted and on, it is not perfect, but it will keep out most of the crap on the road, and 98% of the water.

No I have not done a Compression test yet... that is on for Saturday. I need to do one now!

yes, I am running the 2300/350.
I need to run it up and check the all in on that, I have only done idle readings.
Another thing to check in the morning.. It is a Balster Coil and MSD, wired correctly... but I should verify that.

Those are all good suggestions I need to get that information I have some time in the afternoon tomorrow... I will pick up a compression gauge, but I need another person for that one. Wife may have to help out there!

I left it at 12 degrees and running at 900... it actually smoothed out a bit after the last ride... but the vacume is low... only 10 now on the gauge...

 

[addo]

Hmm... I have been pondering this some more. More people are suggesting it's a rich condition, as I surmised the other week. I have another loopy one:

The ignition (curve and vacuum) are not matched to the cam well enough. The significant initial advance is contributing to the lower vacuum, which is then dumping more fuel.

Quick fix would be a conservative swap-in on the power valve, while waiting to bench-test and dial in the dizzy. After the ignition recurve, do the fuel curve to match.

I am assuming the shop dialled in the cam as required by the card.

Regards, Adam.

 

[CobraSix]

I'm running a 260H Comp cams with similar specs, and having no problems. It does idle rough below 800 RPM, but it runs. The hotter cam will rough up the idle some.

I agree with jack, you are definitely running rich.

Slade

 

[Anonymous]

Nice cam, not really high duration (would need to be above 220 at 50 at least to be high). Should have a bit of a rough idle. If you have a multi key way timing set it may have been set up a bit retarded but I doupt it unless you asked for it to be done. If these specs could be had in a crow cam I doupt it would make power above 4500 rpm (peak) in a 250. maybe different with yours. Still a good cam, wish Id chosen one similar for my car.

 

[BIGREDRASA]

One check for rich/lean is simple enough. Use the high speed idle cam to set the idle up to 2400. Slide cardboard or your hand over the air horn You could also push the choke butterfly closed). If you're close to the mark, speed should start dropping when you cover 2/3 or 3/4 of the air horn. If your speed starts dropping sooner, you're too rich. If later, you're too lean. From your description, I'll bet your RPMs will drop almost as soon as you start covering the air horn.

 

[Anonymous]

Well a lot of stuff to take in...

But I think the problem has to be in the fuel more so than the timing at this point, although Addo your ideas are definitely something to think about...

I am beginning to wonder about the fuel pressure... when I had it running at 2000 rpms I was watching the fuel filter and only a trickle was coming out. Sometimes that thing is full and others there is nothing in it... this might be something as simple as low fuel pressure... I am also wondering about the fuel lines running back to the tank.. at one point they are really close to the ehxuast pipes running back to the mufflers. It is also possible I may have a bad pump. or air coming in somewhere although I cannot find anything leaking. I am running rubber hose from the pump to the carb temp until I can get some metal lines... this is an easy and cheap thing to check first... it would not explain the fouling, but it would explain the surge, and the rough idle. And another thing.. I was running a pressure regulator at one point, and a gauge, and I removed them because I though they were not working... I never got a good reading on the gauge, best was 2-3pounds, and the regulator was not making a difference... my father thinks this is the source of the trouble... he was watching it run and said it sounds like it is not getting fuel consistently?

Now this all could be jetting too, but it would not hurt to check this out first. Just a thought...


I think I am going to swap in a fuel pump first, see if that does anything and read the pressure...
If that turns out to be fine, then I will look inside the carb...

But I think I might as well drive it, it runs OK for now... even though the thing is rich, I will just have to clean house after I get this figured out?

Good test Red... I will try that in the morning.

 

[MustangSix]

That's normal. The filter wil never fill up and you'll only see a trickle going thru it. It simply doen't take that much fuel to run your engine at idle.

Think about it. If you get 20 mpg at 60 mph, you'd be burning fuel at 3 gallons/hr. It only consumes a gallon every 20 minutes or so. It's barely a trickle. Even when you floor it and the burn rate doubles, it still takes 10 minutes to flow a gallon at that rate.

 

[xctasy]

I'll to Wot Jack said, plus this fact.

At 150 hp at full revs, an engine needs about 13.3 US gallons an hour. A Mustang could be doing 110 mph with this 150 hp, and would do about 8.5 mpg.

Gasoline is cheap!

 

[gtm1086]

Question. Is your harmonic ballancer correct, has it slipped which would throw your timing readings way off.
I also agree with Jack. Go down in power valve size. Maybe even a couple of sizes on your high speed jets. But I would go with the power valve first.

Your vacuum seems low. I would think it should be around 16 to 18 although the cam maybe effecting that somewhat.