Hot Rods How healthy is my Flathead V8?

Hello everyone! I recently bought a 51 Ford custom with a rebuilt 8BA Flathead engine in it, very low miles as well, under 10,000 since the rebuild to my understanding. This engine starts up from dead cold instantly, idles without choke dead cold without a single miss, sounds like a monster since they have it running through glass packs, and has a surprising amount of power. I am worried however about a couple of issues. This engine sat for several years. The story goes the guy finished the car, drove it for a couple months, and then passed away. The wife didn't know how to drive a stick so there it sat for 4-5 years. It apparently fired right up without a hiccup after sitting for that long, and other than an oil change done by me has had no other maintenance done, it just runs great. But one of the issues that are concerning me is the amount of lifter tick I'm hearing on the passenger side towards the front. When it's cold with the hood open it is pretty darn loud. After driving around a bit it quiets down by about 50% I'd say but it's still noticeable. For reference this car has an electric fuel pump so it's not a fuel pump making the noise. The other issue is oil pressure. When I first start it, it shoots up to 30psi and slowly climbs to around 40 after running for a minute. Going down the road 55-60mph it always holds 60-70psi of pressure never lower than that, never higher. Once it's hot the idle pressure seems inconsistent though. I've seen it drop close to zero before, at least in the single digits according to the gauge, but normally stays in the 15-20psi range. And when I give it a rev at that low pressure it usually will jump back up to at least 10-15. It could be the gauge, not sure I 100% trust the cluster since it's a digital aftermarket job with a busted speedometer, but it shows no signs of the other gauges being a problem. It never gets hotter than 190 degrees even on long drives on hot days, and it doesn't smoke or miss whatsoever and gets 15.5mpg. Think I should mess with it or is it a gem and I should just keep on driving it as is? I'm not experienced with flatheads so this could be perfectly normal for all I know lol. Thanks for any help you can give me! (EDIT, I should also mention that I've probably put 100-150 miles on the car without the ticking getting any worse)

 

Are you running a filter, if so does it have an orifice on the in port of the filter or line

 

Welcome to the HAMB. You might want to do an intro.I also broke your post up into paragraphs for easier reading.
There are standard tests for any engine, flathead or otherwise. It sounds like you want assurance that things are fine. For real peace of mind, do a compression test, and if it's good perform a full tuneup with oil change and check pressure with a mechanical gauge. You can check valve lash, and it might have adjustable lifters to set clearance.
There are vintage books with this information or dive in here and at the Ford Barn for the specifications and procedures.

 

I know next to nothing about flat heads but guessing it has solid lifters, maybe a valve adjustment will get rid of clicking. As long as you don’t have to adjust often I’d run it. Should have 10 psi or so at idle, keep fresh oil in and run it if it was mine.
Good luck
Dan
PS I’m sure some actual flathead experts will chime in. Found a HAMB link
https://www.jalopyjournal.com/forum/threads/flathead-8ba-valve-adjusting-sequence.1005825/

 

Welcome Fennix
Good to see a 22 year old involved!!!
A flat head - coolest engine ever - never owned one but it’s a dream.
Dan

 

Yes it sounds like you have a good engine.
Before tearing into a valve adjustment, run the car for months. Throw some marvel mystery oil in it to lube up and clean the valve train.
If it continues. Then look into an adjustment.
Your oil pressure is good and considered normal. Run 20w-50 valvolene racing oil. yes you have a keeper there. Let’s see some pictures. Engine too.

yes flatheads are the coolest engines ever.

 

I have a '51 Merc in my '51 coupe. The engine runs very well and has lots of power. On starting, it immediately goes to about 30 psi at cold idle and runs at around 55 psi (the published spec) hot or cold at speed (right on the relief spring pressure). Hot idle is 20 to 25 psi. I have stock gauges and they respond immediately. From what I have experienced and what you are telling us, I would suspect your aftermarket gauge cluster. Also, any decent flathead should have more the 10 psi at idle. Sure, when they are worn out they will idle at 0 psi and run at 10 psi and it doesn't seem to hurt them, but that's for an engine near the end of it's life. I'd try a mechanical oil pressure gauge from your FLAPS.

There was a thread by a guy on "The Ford Barn" just a day or two ago who had the same problem. He had purchased a '39 with a "rebuilt" engine that had sat a while. He had a problem with "clicking" sounds as well, and ended up pulling the intake and checking the lifters. Sure enough, it had adjustable lifters and some of them had backed off to almost .040" (spec is .012-.014"). There are a couple of things to be aware of here. First current adjustables are not of the quality they used to be and have problems with loose adjusters and being too soft. Because of this, a simple adjustment to spec may turn out to be a short term fix. Second, if it doesn't have aftermarket adjustable lifters, a simple valve adjustment becomes a more complicated job, requiring partial disassembly of the engine.

One of the first things you should do is take a compression check, which will give you an indication of the overall condition of the engine (a fresh rebuild should have something over 100 psi on all 8 cylinders and they should all be between 5 psi of each other). If you do tear into it, take note of the cleanliness of the inside of the engine, which should also be an indication on it's overall condition.

One last thing. A good flathead doesn't need heavy oil. I personally run 10W30 from the Dollar Store. Any currently available oil has an additive package more than required for a flathead. Heavier oil will just make the engine work harder and generate wasted heat. Also, DO NOT fall into the "old wives tale" about using non-detergent oil in your car. All it will do is sludge it up.

 

I run 15W40 T4 Valvoline oil in it, seems to be a great oil for a lot of older cars and it’s cheaper than the racing stuff but still has zinc. I’ll run it for a bit but if it doesn’t get any better or if it gets worse I’ll pull off the intake and give it an adjustment, I know it was upgraded to have adjustable lifters during the rebuild.

 

You want to make sure that any valve adjustments you make are permanent. The usual method is to remove the adjusting bolt from the lifter and squeezing it longitudinally in a vice or press to restore the interference thread in the assembly. Loctite makes a green thread locker (in addition to the regular red and blue) that is for assembled fixtures. Perhaps that would work. Also, when adjusting the valves, spin the engine over a couple of times to ensure the cam and lifters are OK. You shouldn't have a problem, even with minimal zinc in the oil because of the low spring pressures used in flathead, but it's a good idea to check it while it's apart. Zinc additives were not even available in the oil used in these engines for the first 20 or so years.

Running it as is for a while is probably not a bad idea, but I doubt it will clear the noise up. Even though it now has adjustable lifters, they are still solids. The Marvel Mystery Oil and other tricks sometimes work with hydraulics, but rarely on solids.

 

Yeah, I wondered how those fellas thought that running it more would make it quiet down.

 

First, get a mechanical gauge and use it to verify your oil pressure. I've kept one in my "test kit" for years along with a few adapters for installation. As long as you have a verified 5 - 10 psi hot at idle, and it immediately goes up with rpm, I wouldn't worry.

Second, are you sure it is a lifter tick you are hearing. A small exhaust leak sounds very similar and gets better as the engine warms.

 

I would worry, as this is supposed to be a rebuilt engine. I had sort of the same problem with a Speedway Motors oil pump in a fresh rebuilt. Replacing it with a good used tested original Ford pump and a new relief spring brought everything back to factory specifications. Here is the thread : https://www.fordbarn.com/forum/showthread.php?t=244234&highlight=Speedway. If he opens it up and finds it is not rebuilt, well, then he has another issue that he should take up with the seller. And, I still think a compression test should be the first order of business.

I hope you guys are more discerning when you build your own engines.

 

Agreed.

I remember a Ford service manual quote from the 90s. As best as I recall, and the two key words are verbatim;

Power steering pump noise is normal. Unless the noise is extremely objectionable, do not replace components.

I pictured a service writer and a customer out in the drive up area, discussing the noise.

 

Along with a compression test, check vacuum
Compression - Now What?


Result Likely Culprit
Pressure starts low and stays low
Adding 1tbsp of oil does not increase pressure Valves
Pressure builds up, but not high enough
Adding 1tbsp of oil increases pressure Piston Rings
More than one adjacent cylinder show low pressure Headgasket
All pistons show low pressure (<100 psi)
Adding 1tbsp of oil does not increase pressure Timing
No Pressure Piston, Other Engine Damage
High Pressure Carbon Buildup

 

I'm surprised that so many people recommend a compression test. He says it has good power and doesn't miss. His real questions are about the ticking noise and ocassional low oil pressure hot and at idle. That's the first thing I would verify with a mechanical gauge. Do not trust the gauge in the car. If it really drops to zero at low idle, he needs to find out why. If it doesn't then he doesn't have a problem with the oiling system.

I also mentioned that I wouldn't worry about 5-10 psi at idle with the engine hot. Someone mentioned "factory spec". I don't believe there is a factory spec for idle. Everyone I've ever looked up specify at least 1000 rpm and do not give an idle spec.

 

A compression and vacuum test will verify ring, and valve health, valves that need adjustment won’t show up unless severely out of adjustment

 

I would think about dropping the oil pan if feasible and cleaning it out. Your oil
Pressure issue could just be some old gunk in the pan getting into the pump screen I would think.

 

I’ve experienced a “ticking” noise coming from up front and it was the fiber cam gear on an 8ba. Replaced it with an aluminum one and all was good.

 

Remember, this is supposed to be a fresh rebuild. We have to know what we're working with before we start offering suggestions.

 

[QUOTE="jaracer, post: 15289438, member: 64860"]I'm surprised that so many people recommend a compression test. He says it has good power and doesn't miss. His real questions are about the ticking noise and ocassional low oil pressure hot and at idle. That's the first thing I would verify with a mechanical gauge. Do not trust the gauge in the car. If it really drops to zero at low idle, he needs to find out why. If it doesn't then he doesn't have a problem with the oiling system.

I also mentioned that I wouldn't worry about 5-10 psi at idle with the engine hot. Someone mentioned "factory spec". I don't believe there is a factory spec for idle. Everyone I've ever looked up specify at least 1000 rpm and do not give an idle spec.[/QUOTE]

Are you serious? We need to know if this engine has really been rebuilt before we start offering suggestions.

Knowledge is power.

 

Ive had the tube up to the pressure gauge get plugged cause panic... lol

 

Toss the digital gauges
Old solid lift engines make noises.
solid timing gears make noises
Adjust the valves? Who knows if it even has adjustable lifters.
I’d check/confirm oil pressure.
Go from there.

 

Quote from the O/P ", I know it was upgraded to have adjustable lifters during the rebuild."

Let's face it; people lie when selling cars. The FIRST thing he should do is find out what he really has : a fresh (<10K miles) rebuild or an old worn out boiler. It sure sounds like the former, but the stated oil pressure says no. Let's hope that's the digital gauges.

 

Are you serious? We need to know if this engine has really been rebuilt before we start offering suggestions.

Knowledge is power.[/QUOTE]
I don't see how a compression test will tell you if an engine that runs good and has good power has been rebuilt. Engines with these attributes have good compression. If it didn't, it would either miss or be down on power; or both. I don't care if it has been rebuilt or not, I can offer suggestions. The potentially serious problem is the oil pressure. Troubleshoot that first.

With that said, running a compression test is okay, it just won't tell you much.

 

I have seen many flatheads that run just fine with 85-90 psi of compression. They are not freshly rebuilt. If you see 105-110 psi, you can be pretty sure it's rebuilt; 85-90, not so much.

 

Since it has adjustable lifters, remove the intake and adjust the valves.
That will solve the ticking noise.

 

I’ve had very good luck buying rides with “rebuilt” engines.
Sometimes the things hooked to em are the issues. Sending units, wiring ……..
Check the oil with a real gauge

vacuum and comp tests are nice to diagnose with
The clicking noise is hard to tell without hearing it. Every solid lift engine I’ve had had a little.
Same with solid timing gears.

 

As Anthony said above, hook up a real gauge and check oil pressure at hot idle. Flatheads often idle at 5-15# hot at idle speeds that are fairly low, like 500-600 rpm. No sweat, it'll be fine there. Your pressure on the road sounds great! If the gauge says hot oil pressure is good, pull the intake and adjust the valves. It'll quiet it down I'll bet. Then drive it...and don't worry...

 

Again, not a properly fresh rebuilt engine. This engine is supposed to be just that. Engine building is a precision task. Expecting less than optimum results is not the way to go You really have to know what you are working with. I suggest that you review my post on "The Ford Barn" about the Speedway Motors oil pump to see how it should be done.

 

There is possibility that some of the valves could be hanging up in the guides, if only momentarily, causing the ticking sound. It wouldn’t hurt to add some Marvel to the fuel to lube the guides. Then you could pull the intake a check the lash.