Troubleshooting: Engine lacks high speed performance/ power.

[Axle Roads]

It's a stock '67 loadamatic setup. Carb hasn't yet recieved any TLC from me. Turning the air screw 1/2 turn in either dirrection doesn't seem to make any autable diffrance at idle. You might be right about the glow, I don't know. I would have guessed from all my upgrades that I should go more lean. Last time I looked at my plugs no 3 looked dark like it was runing rich/cold. That was shorty after the TFI upgrade. Prob. need to look again to be sure.

 

[MPGmustang]

i don't know what i'm talking about ... but i've been told that if you have had an exhaust leak for too long your valves can go... i hope some one sheds more light/info on this...

how long have you had your exhaust leak?

sorry to hear the fluid didn't help... my problem was i couldn't get off the line, once going it was fine... when hot but same sympton when cold good take off then crappy top end by the time i got home it was oposite, crappy take off and great top end...

are you ticking/taping/rapping ?? if so check your timing...

are the compresions good? are the close to equal in all cyl's?

the vac advance might be bad and you just have it advacned too far so off the line would be good but maintained rpm might suffer form the wrong amount static'y advanced... just a possibility (or i got it all wrong)

last thing i can think of is brakes... i'd check to make sure they aren't on...

-Richard

thing i'm learning -- some times it's the simplest answer that is the correct one

 

[Lupin398]

Couldn't a glowing red exhaust manifold also mean a restriction in the exhaust, like a clogged cat or muffler? I'm still new but I figured I'd toss it out.

(P.S. The bees around my house love the s*** out of my '68 mustang, so if it sat for a while it's worth a shot to see if they discovered the tailpipes at one point and nested)

 

[Axle Roads]

hmm. Now I understand why the compression test is needed. It's been at least a year (1000 mi) since the first signs of an exhaust leak. It's been maybe three months since it's cracked. While my valves were replaced in '98. I'm not sure if he used hardened valves(dumb me tried to keep things stock). I try and protect them by using premium gas and occasional low leaded gas. It's due for one of those treatments.

I started hearing a ticking/taping/rapping about 4 months ago, but each time I've checked my trimming it's been right on the money. Cylinder #6 sounded very slightly off about six months ago when I did the old screw driver to the ear trick (but it was very slight). I've done compression tests on aircraft engines, but this would be my first on a car. Do I need two people, or should I hook up a remote bush button start? (last time I did that my starter drive piston fell apart) When they say ground the coil wire, they're talking about the think wire on the coil, right? Not the + coil wire?

 

[TucsonHooligan]

I had a glowing exhaust and piss poor performance on my '76 F100 with the 300 Six, and it was a badly tuned carb. Mechanic (this was back when I was 16 and didn't know how to tie my shoes, much less diagnose car problems) told me the carb was about to fall apart, loose screws everywhere and way out of tune. I would start there. If it sat for 10 years, theres a good chance its got varnished gas in it an possible clogged jets/passageways etc., which would explain why turning the mixture screw shows no discernable change in performance. Plus the spark being visible on the # 6 cylinder sounds like a frayed plug wire thats arcing (?sp) and showing that spark. They may have dry rotted after sitting that long and the rubber split. Carb rebuild, plug wires and timing check. Thats my 2 cents.

 

[Grandmas6]

I'd start with the carb. On the old cars I've worked on -- 1960 Cadillac and a 1966 Mustang -- the best bang for the buck was tearing down the carb, cleaning and rebuilding it. Even if that isn't the problem, if you haven't done it, it probably needs to be done.

It's not hard. I would make sure you have the Ford shop manual as well as the rebuild kit instructions. Get yourself a brightly lit workbench (a kitchen table works if you cover it up), muster up your patience and get in there. Ignore the beer comercials that tell you a beer in hand is the best way to attack car issues. Washing it, yes. Airing the tires, yes. Even spark plugs, sure. Rebuilding a carb, especially if you haven't done it before, NO.

A rebuild kit is, what, $35? Cheap.

 

[69Falcon]

Ockham's Razor

O K here's the problem: The engine starts out strong and sounds like a beast. After a short distance which varies from a few hundred yards to a few miles the engine starts to loose power and lacks high speed performance. It gets worse over time. When the problem occurs I have to give it more gas to maintain speed, which increases revs and makes a lot noise but doesn't translate into proportionate power at the wheels. Reducing speed increases engine performance slightly. If the problem occurs at a time where I can't easily reduce speed, such as on a highway, revs sound uncharacteristically high and I'm praying that I don't throw a rod, again.

I'd say the problem you're describing is found in your tranny and/or torque convertor. The glowing exhaust manifold and seeing sparks from your #6 cylinder are certainly issues that need fixing, but I don't think they're the source of the symptoms you're describing.

 

[Grandmas6]

Yeah, I'd agree with that. But for its cost, the carb isn't something you should ignore.

 

[Axle Roads]

I learned to tie my shoes by 17 but apparently I'm still making dumb mistakes. It's the EXHAUST side of Cylinder #6 where the Spark is visible at night. Cause: spraying the bolts with penetrating oil, loosening the nuts and then tightening them again. I did this after buying mike's long tube headers and that was 150 miles ago. I've been waiting/ hoping to scavenge used exhaust piped from my local speed shop since. I defiantly made the leak worse, but I thought the only problem would be increased fumes. I didn't know it might harm the valves.

I bought Pertronix Flame Thrower High Performance Spark Plug Wires in October, 08. The only problem I've noticed with them occurred yesterday. I received a shock while confirming the connection by leaning over the car and pushing down hard on spark plug wire #1 with the car running. NOT safe while running a TFI. Should I get one with thicker insulation, or just learn to turn off the car?

So, no ones actually is saying the carburetor could be causing this problem, just that it should be rebuilt soon anyway, right?

 

[66 Fastback]

Something weird is going on with the posts. I posted this earlier and Axle even responded after it I posted it, and I replied to his post. Now they are all gone.
Any way.....

A glowing red manifold would have me concerned. You could damage the exhaust valves. As mentioned, the fuel could be lean or it could also be rich. If it is rich, and you have an exhuaust leak due to the crack, the air will help raise the temps. But I would suspect that you have a carb/timing issue. Retarded timing raises cyl head temps.

If your idle mixture screws are not affecting the idle speed, then the curb idle stop screw is probably set so that the throttle plates are open too far. This can be a mistake folks make when there is insufficient spark advance at idle. More advance at idle smoothes out the idle and allows you to close the throttle plates more fully. If these are set properly and the problem persists, you may have other issues with the carb or distributor.

With a Load-a-matic, not only does the vacuum cannister need to function, but the SCV (spark control valve) needs to function. You could have something sticking in the SCV operation that is not allowing the timing to advance at the higher rpms, hence the poor performance, retarded timing and hot exhaust manifolds. Check to make sure that the distributor linkage is advancing the timing when additional vacuum is applied to the line feeding the distributor. It would be a good idea to verify that the timing mark on the harmonic balancer has not slipped.

You need to get back to the basics and check the timing and set the idle speed, verify the TDC of the balancer etc. An engine not tuned properly can result in the symptoms you describe. Fix the engine before you start worrying about the secondary things such as the transmission etc.
Doug

 

[Axle Roads]

My posts are intermittent as well Doug. I posted my compression figures earlier.

I'm thinking about what you said. I'm not sure about checking my chain, but I'd like to learn how to:

Check to make sure that the distributor linkage is advancing the timing when additional vacuum is applied to the line feeding the distributor

I've wanted to do this for awhile but I've been unsure how to set this up in my driveway, SAFELY. Do I block the front wheels and put cinder blocks under the rear axle. Than have someone step on the gas while I stand next to the car and measure something at the linkage?

I'm pretty good at testing things at idle but when it comes to moving wheels I'm a freshman.

 

[CoupeBoy]

You might be bettter off using a dialback timing light rather then trying to measure anything. Set your timing with the vacuum disconnected then rev up the motor and see where your harmonic balancer 'moves' to. If it does not 'move' then you got issues with stuck advance linkages..

-ron

 

[JackFish]

I posted my compression figures earlier.

I was looking for those, where did you post them?

 

[Axle Roads]

My Compression Figures

Once the server's done having a seizure your posts will prob pop back up, I did read a few of your posts that I don't see up with now, but just in case here are the numbers again.

As I said before. The most accurate numbers are in the middle. It took me a few tries to learn to crank the engine enough times and remember to reset the tool. At some point toward the end, one of the rocks I had on the gas peddle fell off and my battery started running low.

 

[cobraguy]

Axle with your timing light on it and the car running at idle unplug the vacuum line to the distributor and plug it into a manifold vacuum port. You should see the timing move. If not get a vacuum pump and test the vacuum advance diaphram. Your glowing exhaust and lack of performance is classic late timing. Read the load o matic stickie and see if yours is working right.

 

[Axle Roads]

You might be bettter off using a dialback timing light rather then trying to measure anything. Set your timing with the vacuum disconnected then rev up the motor and see where your harmonic balancer 'moves' to. If it does not 'move' then you got issues with stuck advance linkages..

Sounds obtainable Ron. I have an older style AC liming light (not a dial-back timing light). Doesn't matter for this test, right? Are you suggesting that I rev up your engine, with or without the vacuum line hooked-up?

Axle with your timing light on it and the car running at idle unplug the vacuum line to the distributor and plug it into a manifold vacuum port. You should see the timing move. If not get a vacuum pump and test the vacuum advance diaphram. Your glowing exhaust and lack of performance is classic late timing. Read the load o matic stickie and see if yours is working right.

I have mettle vacuum lines. Are you used to doing this with flexible lines or is the distance between the tube adapter and a manifold vacuum ports small enough I wont damage the line.

 

[CoupeBoy]

it really doesn't matter which you have, as you can still witness the timing mark 'move' when you unhook the vacuum and/or rev it up. My wife bought me a dial back timing light a few years ago and I use it to 'predial' in the total timing when setting initial (idle) timing then the mark is always at '0' and when it revs up you can easily read on the timing mark how many degrees it moves.

but no you don't need one, any timing light will do, I'm just spoiled.

And yes he was implying that you should unhook your metal vacuum line from either the carburator or the distributor to test the vacuum advance.

-ron

 

[Axle Roads]

Observations: timing = 14*; distributor vacuum tube adapter @ idle = -2.5psi; vacuum line connection at the diaphragm is stripped; Teflon tape is worn.

I need to improve this ->

connection before moving on. Dumb question: if the threaded vacuum fitting continues to spin indefinably, which side is stripped, the male or female?

 

[CoupeBoy]

question: if the threaded vacuum fitting continues to spin indefinably, which side is stripped, the male or female?

If you are losening it, it could be either one, nor neither. Sometimes things like hardlines with fittings are completely disconnected but the steel line is seized to the metal flare inside the fitting. If you've loosened it adnausium and you are sure that it's lose the flare on the tubing is probably just wedged inside the distributor, try moving the hardline back and forth while pulling it out. Another way to test if its stripped or not would be to try to thread it back in. But this will be inconclusive, if it works then obviously things aren't stripped but if it will not thread back in then it could be a misalignment between the fitting and the vacuum advance.

-ron

 

[Axle Roads]

It's the other way around. Sorry for being unclear. I tighten them ad nauseum. I feel a slight resistance and then it slips past for another rotation. Same question.