Unidentified knock

[Toid]

I got the news nobody wants. Changed the oil and got a knock for my trouble.
After reading 45 dozen posts, articles... All I am is more confused. Diagnosis is not my forte.
Knock at idle, disappears at 1500 or so, can barely hear it come back maybe 2500 or so as a light tapping... If you let go of the throttle.
Oil pressure is rock solid at 50/35-40 (power/idle) when warm & 50 cold.
Read that a complaining rod will disappear if you unplug the cooresponding plug wire at idle. Zero effect. The sound radiates from pass side only... Haven't checked bolts on flexplate yet, but will in a while.
You fellers have proven to be useful, so I shall not destroy this planet as long as you prove valuable.
Rev. Toid

[brianj]

What did you use for oil and a filter? (Brand and viscosity ) What motor and mileage are we talking? I can't remember your specs, although I know you posted them elsewhere.

[Toid]

It's a 90s era roller motor less than 70k. PO says went through it less than 5k ago. Checked tolerances on Bearings, etc. Absolutely wasn't knocking before oil change. Went with FL1a, conventional mobile one 10w40 & Lucas. Anything else I need to tell you?

[cb84capri]

Don't freak out, it may be a lifter. I have a lifter in my truck that likes to make noise if I move the truck around driveway and stuff and don't let it get up to operating temp. The next startup it continues until it gets to temp and I drive it about 5 minutes after. I suggest letting it warm up to temp at idle and drive it easily a bit and see if it disappears. I always try to put as much oil into my oil filter at oil changes as I can without spilling to minimize the amount of time it takes for the oil to get to the bearings. Also make sure you put the right amount of oil in - with a stock oil pan it's around 5 quarts.

A mechanics stethoscope can be purchased pretty cheaply. They are very useful for helping to pinpoint these kinds of things, better than trying to listen through a long screwdriver.

Cale

[Toid]

I have a policy of filling it up & just letting it spill... Would changing from a synthetic to conventional do this? It has been said, but I don't know...
Is there a solution for a lifter... Other than offing the intake and swapping them?

[brianj]

I'm not a believer in oil additives - the Lucas bit makes me wonder. I'm actually leaning towards a lifter as well. I have seen overly thin oils cause this, and I've also seen defective oil filters cause it as well. Having used good brand parts, i doubt that is it. Unfortunately, it's hard to tell through the computer. Any chance you could post up a video?

[Toid]

In a Ford, I pretty much stick to Mobile 1 and Motorcraft filters.
I can do this, likely on the morrow.
I got her up on jackstands right now, checking the Flywheel for cracks and looking at the TC bolts to see if, for whatever reason, they started whacking the shield behind the engine. I don't like to run em tilted back like that. I'll set her down tomorrow after work perhaps, and see how the Droid sounds on a video..
I've rebuilt a clutch of engines, mostly SBCs, but a Ford or two also, never had a lifter go bad, so I dunno how to check, except to guess it'll show in the tolerance at the rocker arm. It's not going to be VERY aggravating to pop off the intake, it's almost clean as a pin under there. No grease/oil at all and minimal dust. Like I said, hasn't been long gone through... the silicone around the gasket areas is still nice and pretty.
I'm not absolutely sure about the specs on the motor... I guess it matters not, as long as I got lifters for an early 90s roller cam 302, right?

[erratic50]

My old 86 HO has over 440K miles on the clock and counting. It hasn't been torn down or gone through, etc. Mine developed a tap at around 230K miles. I trace it to a roller lifter also on the passenger side.

I double checked rocker arms and push rods on mine by visual inspection because I needed valve cover gaskets anyway. That allowed me to see one lifter that visually looked gunked up and shoot brake cleaner straight down to the lifter with a straw. This may have helped my efforts- not sure. The car sat overnight as I didn't put it back together until the next morning.

Before I started it the first time again I drained out oil until the add line.

I ran the motor at idle until it was warmed up

I adjusted the idle so it ran at 500 and rigged a tach under hood.

I added a small bottle of engine desludge and part of a bottle of marvel mystery oil and ran it for 5 minutes. I varied RPM between 500 and 1200 while running.

I turned it off and drained it.

I installed a puralator oil filter- don't get cheap crap like fram - they flow poorly and bypass frequently.

i put two 100 lb pull cup magnets on each part of the oil pan which I now remove every time before I drain the change oil. Any my oil has had metal shine to it every change for at least 200K miles but it's been OK.

I filled it with high detergent oil 4 quarts conventional Mobile 10W40 and 1 quart slick50. I started it back up and ran it for 30 miles in 5th varying speed between 45 and 65. I had 2.73:1 gears and .68:1 OD T5 at the time. 1000-1500 RPM

I perminately set my idle up to 1000 RPM.

Knock on wood it's been fine ever since. It even saw the 6250 rev limiter, etc, a few times this past weekend while I was running it hard for fun.

Not sure about the advantages of synthetic vs conventional for this operation. I used conventional but it was 15 years ago so what's available has changed.

I was always told NEVER - EVER run synthetic in an old pushrod engine during breakin as it makes them use oil from day one and never stop. Don't know if that's true but I've always lived by that rule until a newly built combo has at least 10K on it.

My dad built a lot of engines when I was little. Old flat tappet cams, etc. First 20 minutes held at 2000. Then He would always run slow and change oil at 50 miles, 250 miles, 500 miles, 1000 miles, 2000 miles, then every 2000 until 10K then space out to 3000. Inspecting for metal all the while. You would vary speed between 30 and 45 and never go over that for the first 500 miles. Never over 60 until 1000 miles. The theory behind it was engine harmonics related and was old school hot rod stuff, but I will say his motors never burned oil and I've seen them stay together for a very long time under severe abuse. A few of them ended up on the track race track after the car body deteriorating to nothing around the drive train and they hung in there through it.

Good luck, God bless.

[Toid]

I've always been nervous about internal degreasers... Have read all the stories from Marvel Mystery oil to ATF in the crank case and idle it for 5 minutes, etc.
I guess it can't HURT any more than it already has, huh?
I thunk about going bananas... if the lifter theory is founded. Every story I've read of rod/main noise was accompanied by low or fluctuating OP.
Mine is solid, stoic, and like Brady after half time. I watch OP and temp like a hawk, after my 84 Capri RS threw an oil pump at 90mph between Ft. Devens and Fitchburg, MA.
From what I've read tonight, I can pop the valve covers and tell pretty quick. If I can depress the lifter with my bare hand without too much effort... or if my pushrod is just not pushed up, I guess I've found the culprit. I need to go get a set and soak em. Prolly wouldn't hurt to go ahead and do the pushrods too... Especially that one, if not all.
I can say, I've never pushed a rocker arm to see how "tight" a lifter is supposed to be. I just bolt down the rockers and check the lash with feeler gauges on solids, or go with the book with hydraulics. never "rested" them. My mentor, mechanic and racer for 40 years, always said, "just tighten them down until the engine skips, then back them off til it stops and call them "adjusted"." lol. Always worked!

[erratic50]

I've always heard make sure the rocker tip is centered. Get the correct length pushrods using a measurement tool. Go to zero lash plus 1/4 turn and lock it down.

But a desludge isn't going to hurt anything. And it might help.

On a cheap refresh a lot of guys will reuse the stock lifters and even the cam. If they did a bad job of cleaning it could very-well be the problem.

As for the oil pressure, are you looking at a manual directly connected gauge or an electronic one?

Stethoscope is still a great idea to find this tap.

[Toid]

It's a manual... I wouldn't trust a stock oil gauge even if it was digital! It got an E cam, and intake, so I'm ASSUMING the guy put new lifters in...

[Toid]

I haven't pulled the back off the gauge to see if it's a tuber or all electronic. It's an autometer.

[cb84capri]

You can take the Ford lifters apart pretty easily and clean them out. There really isn't much to them.

Cale

[Toid]

Took off the valve cover, not even "set in" well yet. It was cork, anyway, so I was glad to put a good felpro rubber one in.
I checked the rockers, nothing out of place... pushrods seated in the rockers well. The rockers bolted down tightly. I checked the pushrods & reinstalled them & torqued rockers back down and attempted to manually depress the lifters (platforms) to no avail. So they're not squishy at least. I'm caught between flushing it or leaving it be & swapping motors. Only issue with flushing it is IF it's not an issue of a hydraulic nature that the flush will cure, I'm only worsening the condition of the crank/camshaft(if it's in the valve train and wearing on a lobe).

[Walking-Tall]

Did you check each pair of rockers at quarter-turn intervals (following the firing order), at each cylinder's TDC positions for pushrod/rocker slack? ... though I imagine slack anywhere in that department would have been there prior to an oil change... This a knock that continued/s after maybe the first few seconds of firing it up after the oil change? How thick did the oil you dumped out of it appear to be? As nasty and underhanded a stunt that it is, it wouldn't be unheard of for somebody to have put 50W in it to temporarily mask a crank/bearing issue...

[erratic50]

Could always dump in a bottle of STP and see if the knock stops or what it does.

id likely try Slick50.

Its not a cure all, but I was really impressed at the effectiveness of Teflon additives like Slick50 or Duralube, etc. impressed at the problem I caused for myself. 20+ years ago my car had 150K on the clock and I had been using western autos equivalent that carried the same chemical codes as slick50. It was only $8.00 per quart so I ran it every other oil change for a couple years. Eventually it got the bores so slick that the rings came unsealed/seated. I had to use borax slowly sucked in the PCV valve vacuum line to treat the ring problem. Borax cured it and compression went back to levels expected from a pushrod 86 5.0 when new. Lucky for sure, but my point is that Teflon additives do really work in certain instances.

Other than the heavy treatment with Slick50 and regular oil changes and, lets face it -- just keeping oil in it a there aren't any great explanations for why my motor is still running and making good power. Forged pistons and chrome rings and a roller can I guess.

[Toid]

I put Lucas in it. I typically use Lucas or STP. Ain't never tried both, though. Superfluity rears up to mock me. Ive not experimented much with additives... I did commute 160 miles a day for a while in an Infiniti G20. I put over 280k on it and when I parked it, it literally purred. I got it with 66K, used Valvoline & stp. At 100k, a guy I trust mentioned Restore additive. I used it every 3rd oil change. I kept the fluids right, but never did a thing to the drivetrain 'cept change the NGKs. Got 34mpg with the AC on, didn't use a discernable drop of oil, and that SR20 engine pulled as hard as it did the first time I drove it.
I guess I trust that Restore stuff, for high mileage stuff.
Got a guy I church with jumped on me (for not coming to him first). Runs a pretty modern shop in town (I can't usually afford them)... He's coming to get the 'Stang Monday on the rollback. Gonna scope it, diagnose it and repair it for me. We'll work it out, he says. He's got lots of upholstery work for me to do, anyway. Fine young man... Really blessed me. I wasn't looking at a big mechanical endeavor with this car. I was banking on primarily a cosmetic & custom project. God Bless Him.

[brianj]

I'm really thinking (hopefully ) it's something simple. I keep coming back to it starting after the oil change, and i can't help but think it is something along the lines of a bypassing oil filter or a collapsed lifter from ingesting a blob of Lucas.

[erratic50]

I just realized - have you tried removing the dip stick? I've had mine make contact.

[Toid]

I did not remove the dipstick while running.
That'd be a first for me to come across that. A day where you learn a new thing is not wasted.
But ... The "knock" is not instant. It manifests less than a minute after startup. An obstructive cause, such as a dipstick, bent pushrod, maybe even a broken skirt would be instant, I'd think, with the first rotation.
Maybe I'm thinking wrong.

[erratic50]

Agreed. Not the likely suspect.