Troubleshooting my FE

[CompFi]

I have a 427 side oiler from Shelby engine, 496 CID. It came from Shelby with the Holley 80805 carb, which is the 4150 Ultra XP model rated at 950 cfm.
Then:
• In 2022 when I bought it, Billy Andrews of HRE sorted and tuned the car. The engine was simply a rocket. No issues whatsoever.
• The plan was for me to return the car to Billy in summer of 2023 after adding approximately 1000 miles and he would make any necessary adjustments to the tune.
• Sadly, Billy passed away last year. I am grateful for the opportunities to hang out with him in his shop. We laughed a lot, while I learned a lot. I miss him…

• I still have a lot to learn. I am willing to learn, or at least attempt anyway….
• The 2023 driving season started where we left off in 2022, no issues.
• But as Billy expected, the engine began to run rough in the middle of the driving season last year. I noticed some lag in 2nd gear around 2k rpm, where previously 2nd gear had been exceedingly responsive.
• I also noted rising operating temps, even just on a cruise of country roads. Sometimes hitting 100 degrees Celsius on the water gauge.

• Fans would kick on and mostly prevent temps from rising further.
• Coolant would be expelled from the puke tank out the overflow hose. I would regularly add coolant to minimize risk of overheating.

• But I didn’t like the rising temps so I decided to stop driving it.
• I also tried Patrick’s trick of blowing out the air bleeds. [Holley Carb Woes - DCDoug Pay Attention (Long Post) Hoping this would solve my problem, but same issues.
• Asking around, I took the car to a local shop claiming to specialize in the restoration of 60s muscle cars. [I say “claim” because the shop only had one person who worked with carbs, as I think the majority of their business was resto-mods etc]

• The shop could not replicate the rising engine temps, but admittedly I was not eager for them to take the car for long jaunts thru the Vermont countryside.
• The shop did however note the lag in the power band. The proposed solution was to swap out the carb from Shelby with a much smaller carb.
• Noting how well the engine ran when I first received it, I declined any modifications. Paid my bill for them not to fix the problem and took the car home in its original config.

Now:
• I have my original carb back from Dave Bergeron [thanks to Jeff for recommending!!] who rebuilt the carb over the winter. Dave said that the carb was mostly clean and he restored it to factory settings since I could not confirm if anyone had made any carb adjustments to where Billy set it.
• Since I already had the carb off, I opted to add a turkey pan. I have read about how the turkey pan changes air flow Turkey Pan on Side Oiler. Right now, I still have the basic air filter. Pretty sure it is the S&H that nobody seems to like other than for eye candy, so I understand that I might be swapping that out for something with increased air flow, like the K&N Extreme. If I can find one….
• I have always used ethanol-free fuel. Too many bad experiences with ethanol, so ethanol-free only. 91 octane is the highest ethanol-free fuel available here in VT.
• I just received my new Holley bits to re-plumb the fuel line to the carb to allow for the turkey pan. Carb and turkey pan installed. Everything fits well. No fuel leaks.
• Engine started and ran. Too rough at idle, requiring me to keep the throttle around 1100 RPM to avoid stalling. But I wasn’t too worried about that, as I have not yet followed Holley’s detailed instructions for setting the idle etc
• I paid close attention to the water temperature. Even at idle, water temp rose faster than it should. At least, faster than it did previously when it ran so well. Fans came on around 90 degrees or so. I cut the engine.
• After letting the engine cool. It re-started easily. After initial warm up, I gave it some gas. It backfired thru the carb and stalled. That was new, never previously happened. I don’t know if the shop last year messed around under the distributor. I certainly have not touched it since Billy first tuned everything.
• Per Dave Bergeron, I have fresh plugs to install once I think I have the carb tuned properly. Per Shelby, I have a new set of NGK R5672A-8 plugs. NGK recommends the gap for those at 0.0315”

So, what should happen next? Moving forward, I know enough about Troubleshooting to change one thing and one thing only at a time. Should I focus on timing before following Holley’s tuning instructions?
All insights welcomed and appreciated. Sorry for the long post, but hoping that this post will serve others in the future facing similar issues as I pledge to update this thread with my progress. Or lack thereof
~ Brian

[rustyrims]

does your distributor have a vacuum advance ? does it hook to manifold or ported vacuum? If the distributor is hooked to manifold vacuum it will affect engine temperature and how fast it warms up. if you could check and post the current timing .

[patrickt]

Originally Posted by rustyrims

does your distributor have a vacuum advance ? does it hook to manifold or ported vacuum? If the distributor is hooked to manifold vacuum it will affect engine temperature and how fast it warms up. if you could check and post the current timing .

Timing is as good as anything to check first. When you do that also pop the distributor cap off and see if either of the springs are broken or if the little ball in the center of the cap is burned up or broken.

Since the engine had been running great, did Billy say he expected the engine to start to have a decline in performance after a few hundred miles? Or was he just going to tweak it a bit after it was nicely broken in?

When you start the diagnosing, don't take anything apart until you find a clue that the part is misbehaving. It's likely something relatively simple.

[DanEC]

I’ll add a vote to look at the distributor setup and timing. What are you running for ignition?

[Morris]

Vaccuum Leak…..Check all ports on Carb & manifold…

[CompFi]

Thank you for the reply.

Originally Posted by rustyrims

does your distributor have a vacuum advance ?

No. At least, I am reasonably convinced that there is no vacuum advance since I could not find any vacuum line from the distributor. Nothing to the carb nor the manifold.

As for timing? I will need to get back to you. I need some adult supervision on that one, which might be a few days before I can entice a knowledgeable buddy to lend a helping hand.

[patrickt]

Originally Posted by CompFi

As for timing? I will need to get back to you. I need some adult supervision on that one, which might be a few days before I can entice a knowledgeable buddy to lend a helping hand.

OK, for now just take the distributor cap off, it lifts right off after you turn the two lock down a half turn each, and look to see if the springs are broken.

[CompFi]

Originally Posted by patrickt

Since the engine had been running great, did Billy say he expected the engine to start to have a decline in performance after a few hundred miles? Or was he just going to tweak it a bit after it was nicely broken in?

Definitely the latter. Some tweaking after broken in as necessary.

I have not yet looked under the distributor. I have a basic understanding of what I should see there. Basic, as in, maintaining an old inboard, marine engine which is about as basic as it gets....

But thanks for the guidance on what I should be looking for under the distributor cap.

[CompFi]

Originally Posted by DanEC

I’ll add a vote to look at the distributor setup and timing. What are you running for ignition?

Thanks Dan.

As for the ignition? I am embarrassed to admit, but I don't know. Overdue for me to learn, so I am playing catch up here and trying to be methodical. Both with my education and troubleshooting.

[patrickt]

And there are two easy ways to check for vacuum leaks. First, just get a mirror and angle it so you can see under the base of the carb and look to see if the port tubes have lost their little black rubber cap. The second way is to have your engine idling and use a butane torch that is not lit to spray gas around the base of the carb while it's idling to see if it revs up by sucking the gas in. But for now, let's just stick with the first way.

[patrickt]

Here's a before and after pic of my distributor after I cleaned it up a bit. Note those two springs and how they are attached. They are attached to weights that spread out from centrifugal force. The strength of the springs control how quickly or not they spread out. Spreading out actually changes the timing, so you want them to spread just right, not too fast and not too slow.

[IMG][/IMG]

[CompFi]

Originally Posted by patrickt

OK, for now just take the distributor cap off, it lifts right off after you turn the two lock down a half turn each, and look to see if the springs are broken.

Thanks again for the step by step guidance. Greatly appreciated!!

To my untrained eye, everything looks good. Springs are NOT broken. And cap looks good. If I can decipher how to post pix, I will do so next.

Also, shout out to Brett Lykins for this very helpful vid on recurve of MSD distributor for FE: https://www.youtube.com/watch?v=gVKIAdbzT4I

[CompFi]

pix of cap, rotor and springs:

[patrickt]

That looks new, and fine. Proceed to looking with a mirror to see if you lost a vacuum tube cap.

[CompFi]

Originally Posted by patrickt

And there are two easy ways to check for vacuum leaks. First, just get a mirror and angle it so you can see under the base of the carb and look to see if the port tubes have lost their little black rubber cap. The second way is to have your engine idling and use a butane torch that is not lit to spray gas around the base of the carb while it's idling to see if it revs up by sucking the gas in. But for now, let's just stick with the first way.

Ugg. Checking the vacuum tube ports under the base of the carb would have been a LOT easier before I installed the turkey pan. I just tried to squeeze my phone in there to snap a few pix, but no joy.

In an attempt to eliminate the carb as the likely culprit here, I sent the carb out earlier this Spring to be rebuilt by Dave Bergeron. Just re-installed it this past weekend. Which of course does not guarantee that the ports are plugged as they should be.

But then again, do I want to try the butane approach when I had a backfire in the carb?

If I need to pull the carb to confirm the ports are plugged as they should be, then so be it.

[patrickt]

Google some pics of your carb so you know exactly what you're looking for. There's a pretty big vacuum tube towards the rear that is for the brake booster. Maybe you have that hooked up to your PCV. If that was just unplugged and completely open it would be a monster vacuum leak. Then you're going to have a smaller vacuum tube, mine is on the front base of the carb slightly towards the passenger side. When I put a vacuum gauge on it I have to use a tool, I can't do it with my fat fingers. Then there will be another tube, maybe on the primary metering block. Once you get the hang of looking for them they'll jump right out at you.

[Grubby]

Some of the High Performance 850-950 Holley style carbs have NO vacuum fittings.

I suspect the shop that worked on it may have changed some carb settings or jets/bleeds.

If the timing is right - roughly 16 degrees at idle and 34-36 degrees at 3000 RPMs, I would bet for lean condition.

I would go thru the Holley dial in procedure step by step.

John

[eschaider]

What you have is a tuning problem and perhaps some parts that need replacement/adjustment, Brian.

Using a remove-and-replace strategy/approach to resolving the problem is going to be the long way home to an incomplete solution; although you might get lucky — you probably won't. When you are done, you will either still have the driveability problems or you might be modestly better off.

The one-shot fix is going to be challenging. You will need to find a tuner with a dyno who actually knows how to tune Holley carburetors. These are increasingly rare birds because most shops are geared to tuning EFI with a laptop.

When you find him, the ante at the poker table is likely a half-day on the dyno, some jets, air bleeds and other Holley-related paraphernalia, potentially an ignition clean-up, and a fair amount of money to pay for the dyno time and the tuning job. My guess, and it is only a guess, is you are around $800, depending on how the dyno time and tuning knowledge are priced. For the most part, the parts will be incidentals.

When you are done, you will have a very driveable engine with good street manners. Maintaining that engine personality over time should be relatively easy.

BTW if you have anything in the distributor that needs replacing you should throw out your distributor and buy one of these => https://progressionignition.com.

In addition to being infinitely tunable, it also has an electronic engine disabling capability that is activated from your cell phone and is impossible to override without replacing the distributor. The Progression toy will set you back another $570 or so, but it will work flawlessly and outlast you and the engine.

[CompFi]

Originally Posted by Grubby

Some of the High Performance 850-950 Holley style carbs have NO vacuum fittings.

John - thanks for the tip here. As I would like to avoid pulling the carb if at all possible.

Here is a pic of the underside of my carb that I pulled from the Holley website.

Problem is that I have no idea whether this pic depicts any vacuum fittings

[Grubby]

No vacuum connections in the carb shown in the photo.

John