noise repetative like a tappet but NOT a tappet 1963 thunderbird 390

445

Asked by neilwillis Feb 14, 2020 at 02:03 PM about the 1963 Ford Thunderbird

Question type: Maintenance & Repair

ford 390 sounds like a noisy tappet but I've tried everything that would
suggest a tappet noise. , there's no feeling when I touch/press on each
rocker, there's no space between the rocker arm and the spring valve end,
the pushrods seem tight on all the cylinders. , the noise is repetitive in time
with the engine. it does go off when the engine runs faster suggesting a
tappet noise, it appears to be possibly from the rear of the block and i think
on one side only on the passenger side (US vehicle). I've done the washing,
changed oil, several flush things. one thing you may help me with, years ago
we would have put in  thicker oil I ( but that was before lifters were used)
so some outside the box thinking on this one.  thanks.   Neil

18 Answers

291,965

Exhaust leak?

1 people found this helpful.
217,005

Well the 390 uses hydraulic lifters and as the sound disappears as the rpms rise I would start by checking the actual oil pressure, if that is good then you may have a weak lifter or a slightly worn cam lobe on that one cylinder.

1 people found this helpful.
445

Thanks, F_O_R The problem is I can't identify where the sound is coming from, I've had earphones on each rocker/push rod, etc but even when it's running slow and the noise is quite loud I can't identify where. you mentioned the exhaust can you explain a little further? I've looked online about changing lifters but I can't see how they would pull up through the small pushrod holes, is that accurate, 1 remove rocker tube and rockers, 2 pull out the pushrods then the lifters? I'm reluctant to take off the centre manifold and repair it that way any suggestions

445

Thanks, GA I'm retired and have done most things like yourself, although I'm not a mechanic, I'm stuck with this one there should be an obvious answer, the problem is that here in England there aren't too many garages with experience of us cars I'm going to try some classic motor oil to see if that helps, Q How can I test the oil pressure? anyway thanks for your previous help Neil Willis

217,005

To test the oil pressure you can install an analog gauge in place of the existing oil pressure sender as this is just temporary don't damage anything during the install. Now the lifters do send oil up through the push rods to lube the rockers contact points. On these old engines you really need to replace the cam as well as the lifters as a set then run a cam break in session. Now you can take a chance and replace the lifters by themselves but you run a chance of ruining the old camshaft, plus you will need to remove the intake manifold to gain access to the lifters as the holes in the heads will not allow the lifters to be pulled all the way out and they will fall into the valley, now if any of the lifters have and convex wear in them then you must replace the cam, timing chain and gears. As the cam has to come out of the front everything forward of the engine has to be taking out of the way. A big messy job.

Best Answer Mark helpful
445

Thanks, GA if I could only find out which lifter is tapping, the manual says to place your finger on each one at a time ( doesn't say if running or not} I'm wondering if checking the rockers arms will tell me anything, someone said it could be worn, but unless its a real groove how can I tell which is worn. anyway ill just keep at it fr now. if I took both heads off then the manifold is that it to get access to the lifters ( as I cant pull them through the pushrod holes ( even though there is a youtube apparently showing this). any suggestions I've also changed the oil several times and filter. thanks, guys

217,005

I’ve always used a mechanics stethoscope with the engine running and put it right on each valve rocker stem and listen for the noisy one. You can cut a piece of cardboard up to keep the oil from slashing onto the exhaust temporarily. You will not need to remove the heads just the intake to get to the lifters. Check each pushrod carefully and if you see and chipping or uneven wear replace the pushrod. Don’t forget to check each lifter for dishing on the cam side, if you find any then I would advise you to replace the cam and lifters. I probably already stated that but it bears repeating.

1 people found this helpful.
445

Thanks, I've taken the car to a garage and they say changing the lifters will not stop the problem, as I've got 16 new ones from Rockauto am I correct in saying that changing them won't do any damage, they are going to change them but the mechanic says they need adjuting from the TOP on this motor FE 390 1963 I thought that the rockers ere not adjustable, is that correct or is he talking about something else?? thanks

217,005

There is an initial lash adjustment but once that is set the lifters should remain quiet, if the noise comes back then you need to dig deeper like the camshaft, cam bearings etc. I really don't like putting new lifters on an old cam cause if the hardening material has an spots that has been worn trough new lifters will aggravate that condition and cause cam failure. I hope the shop you have it at knows about Ford lifters and what too look for during the teardown.

445

GA Thanks again, I've replaced the lifters. plugs, plug cables, and the tappet sound stops WHEN I advance the timing but I can tell that the motor is running on 7 and a bit cylinders if you can check my most recent question, titled "tappet noise and timing problem \\\\\\\\\\\\\\\\\\\\\\\\\\2 thanks anyway GA

217,005

If it only running on 7 cylinders then they messed something up going back together, a compression test will isolate what cylinder it is that dropped out. It is not uncommon for a pushrod to bend after lifter replacement, compression test will really help.

445

Again thanks GA I can stop the tappet noise by advancing the timing a bit, ill check that actual timing as I'm not sure the garage put it back to normal, but when I retard the timing it taps again although not as loud as before, ill follow your suggestions but first ill check the rocker arms, I've got two for what I'm sure is the faulty cylinder ( number 3), the garage said it's number 3 and demonstrated by pulling the plug lead off number 3 cylinder, naturally the motor carried on but the tapping stopped altogether. if it stops with a small amount of advance presumably that should be temporarily ok but as you said there is still probably a cam worn problem,

445

Thanks, GA, when I pull off the plug, leads from no 3 and 4 cylinders there is a very very small speed slow down change, ( all other cylinders show a clear speed change ), I've changed the lifters, plugs, cables, and no 2 rocker arms, the sound went a little but can still be heard but faintly, I've advanced the timing which nearly stops the tapping noise altogether when I high rev the tapping stops but letting go the accelerator quickly makes it tap for a few seconds then goes fairly quiet, could it be faulty valves or valves needing ground into the head to seal better??? You've answered many times and i appreciate that but I am aware you now probably need to move onto other topics, clients' problems. etc so thanks for the help.

217,005

I would run a compression test, both dry and wet, then compare the two, if he compression on the two that are running poorly stay the same then its a valve problem, if the compression readings climb on the wet test then its rings or piston trouble but don't rule out cylinder or head cracking. Sorry your having so much trouble nailing this down.

445

GA oil pressure test and a compression test wet and dry on its way thankfully this coronavirus allows me time to spend in the garage

217,005

At least you can work on stuff. It's been 1 month and a day after my rotator cuff and bicep repair, still got my right arm in a sling and will see my Dr. at the end of April I hope.

445

keep fit and look after yourself GA Arne

217,005

Thanks. At least having the sling makes stay isolated and I can go out on my back deck and get some sun when we have it. Take care of yourself over there.

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