Technical New to Flatheads.... Engine noise ? Normal?

Hello Again....In the 40 years I have been working on cars..I have owned and rebuilt two flatheads..(1) a 1945 Willy's MB Jeep and (2) Harley 45 WL..Everything else has been OHV GM products..Yesterday was a decent day here for January and I was able to get her car outside and running...It has headers and straight pipe and its pretty loud inside of the garage and my hearing is not all that great..I noticed that if the throttle is slightly opened from an approximate 600-700 RPM idle there is a heavy rattle at first and then goes away..It doesn't persist when held at a higher rpm nor at idle....It's just when the initial RPM starts to increase off the idle..It has a wrist pin or rod sound. The seller stated the engine was rebuilt by a reputable shop in his area...I also noticed what looks to be a large amount of ventilation coming from the manifold breather after the engine had been shut down and had been running for 20 minutes or so...There is no smoke from the exhaust..I do know the car/engine has been sitting for a long period of time without use....I removed the belts and the noise is still there and it's not a tick like a lifter...Thanks Eric

 

Forged pistons sized incorrectly??


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Could be a valve sticking a bit . Try some M. M. O. in the fuel. Post this on the Ford Barn; all flathead guys there.

 

Rock the crank, check for timing gear play

 

Where does the knock seem to be coming from? The back of motor?

If so, take it for a ride and try to get it under load in 2nd gear. If the knock is there, could be incorrect advance setting..

Does it still use the stock Load-a-Matic dizzy? If do, you need to address that for it barely worked in stock form. Add two carbs and other mods with it, forget it.

 

Using the old 2x4 stethoscope..I can hear it the most between 1 & 2 cylinder on the driver side..The distributor is a Hunt magneto style..Idles perfect quiet as new car...But when the linkage is pulled slightly to raise the rpm...Rattle/Rattle...There is no mechanical fuel pump either....It does seem to get better when the engine reaches higher temp. Thanks

 

Don't really think its the issue but check the
linkages of the carbs including the choke.
Also check your water pumps and definitely check your pulleys.

 

Are you sure it's not a rocker arm hitting the valve cover?

 

It's just for a moment that sounds like my old Cummins diesel..I just didn't know if some internal noise is a characteristic of a Flathead Ford...People say a leaking Harley Davidson is normal....Some is and some isn't...They can be made leak free with the right amount of money...

 

" rocker arm hitting the valve cover?"

That's a joke, right?

 

Had a motorcycle with loose throttle slide. Quiet on the idle stop but loud rattle when opened due to pulses.

 

What's the oil pressure doing when the rattling starts and stops?
If you pull one spark plug wire at a time does this change the noise any?
Just because it's been rebuilt by a reputable shop doesn't mean they are familiar with flatheads.
Probably wrong, but I'm thinking something might be amiss in the oiling system / rod bearings.
Just a guess and hope it's much simpler.
-Dave

 

On the other hand, I had an 8BA with a similar rattle. Looked for it for a while and couldn't find it. It seemed to be getting worse, so I thought it might be the throwout bearing. I had a fresh Merc ready to go into the car anyway, so I pulled the engine. To do the swap, I had to put the original Ford oil pan on the Merc. In cleaning and preparing the Ford oil pan for use, I discovered a large chunk of the main bearing thrust surface laying in the bottom of the pan. I'm not sure that it was causing the noise, but I sure am glad I pulled the engine.

Bottom line? It could be anything. Hopefully you find it easier than I did.

 

Pull plug on suspect cylinder. Miss / knock difference. Youvprobably already checked..Verify.....wires and firing order are correct,

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Does your distributor have mechanical and/or vacuum advances? Are they working properly? How much initial timing are you running?

 

Being a rebuilt engine, maybe a piston has been fitted the wrong way round on the rod, struck it once on a fully rebuilt engine that I bought years ago, had a knock just like you describe..
Or, you say ''A long period of time without use'' Maybe a piston wrist pin has semi seized, causing the piston to slap??

 

I just ran the engine pulling plug wires. There seemed to be no change with wires disconnected However twice when I put spark back to the #1 cylinder. It made the knock. Also it was less pronounced as it reached normal operating temperature

 

What usually causes a knock,,,?
I know what it sounds like to me,,,but I hope you come out alright on it.
Good luck.

Tommy

By the way,,,,it’s looks like an awesome engine,,,beautiful !

 

I’m hoping someone tells me different. But my money says. When I put the juice back to that cylinder and it knocked = Rod. Screwed Again

 

tear it apart, measure, look for any abnormalities, fix and put it back together. Drive

 

I'm sure you've got fresh oil? And enough , I use oil with zinc? Don't think it's a must but been told a little more protection ? It's been sitting think I'd drive it a little more might need a good cleaning out ,not hard just normal speeds let the temp get up to normal see if anything changes , don't think the worst yet !!!

 

I just purchased the car less than a month ago. I did some transmission work to it seals service etc. and also working on the interior. We haven’t actually driven the car yet. Was in the process of doing some things needed to get it ready for spring. Honestly it had only been started since in my possession to move into garage and then moved to another stall. I removed the hood to do some paint work and noticed this issue during the transmission refill. The oil level is full. According to the seller there was less than 200 miles since the build. The car had been for sale for a while. And I felt for what we were getting it was a fair price. I was excited that what repairs I could see that needed done were cosmetic only. I did not plan on an engine rebuild. Especially when we just went through a 3 year total rebuild of an already over invested eBay purchase that was totally my fault for buying a car on someone’s word that was over 2000 miles away from my location. Having good luck is not something that runs in this family

 

Eric,
At least you got it for a good price.
Can you remove the pan easy ?
All you would be out is a gasket,,,,and if that’s it,,,,it’s got to come off anyway.
Since you are not new to this,,,,,sometimes you just get a feeling about these things.
Also,,,,,#1 and #5 are the last rods in the oiling system .
Keep us posted .

Tommy

 

Eric,
It sure sounds like you will have to do some investigating. I wouldn’t trust the rebuild. Sorry about your luck. Looks like your being baptized into the flathead world. That oil pan may remove without having to disconnect the engine from the tranny.
Good
Luck.

 

Do you have any idea what state of tune it's in? Is the distributor clamped down properly or was it left loose? Have you done a compression test or checked the manifold vacuum at idle. It probably won't make any difference but you might try "un-bundling" the plug wires and rerouting them, at least temporarily, so they don't run closely, side-by-side, over any great distance. While you're at it check the firing order and make sure the wires are going to the proper cylinders.

 

One thing that I failed to mention was that I had replaced the plugs...Reason for this was they were very rusted from the vehicle sitting outside and I was concerned they were possibly seized in the aluminum heads...I had pulled a couple and noticed they were carbon fouled from what I thought was idling and not being run...When I fired the engine to refill the transmission fluid...There was a bad arc from the #1 plug and we all noticed the knock...I assumed I had cracked it on removal due to them being rusted and tight....I had not installed the new plugs yet but had them on hand.I wanted to clean the heads/intake etc with cleaner before I installed . I replaced that plug and the arc was eliminated
The next day I replaced the other 7 plugs..The replacements are a higher heat range than what was in the car NGKB4L/3112 replaced Autolites...As I said I've never owned a flathead Ford but never had issue with using a hotter plug in a sbc I haven't checked the timing as the way it starts and idles I felt it was better to leave it alone...I plan to check compression and I also ordered a replacement oil pressure gauge this morning,,I believe the one currently in the car to be giving a false reading ...Going from electric to mechanical ..Thank you all again for the information

 

IMHO: I would dump the oil & see if there is any metal or any other noticeable contamination there. Oil is cheap.

 

Like he said, drain the oil in a clean pan. Then take the oil filter apart and watch closely for metal

 

Pull the new sparkplugs and see if any have the electrodes pounded flat. I've done that before.

 

To me that indicates spark knock. You even mentioned that you went to hotter plugs. Anything in the combustion chamber that can induce ignition before the spark will cause that knock, including a hot plug.