Need help with finding engine noise

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Model T Ford Forum: Forum 2017: Need help with finding engine noise
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Monday, September 25, 2017 - 08:10 pm:

This may take a bit to explain so please bear with me. What I have is a 26 touring that has a knocking noise that sounds like a rod when it is started hot after sitting for about 20 minutes, the noise lasts 10 to 45 seconds, if it cools down it won't make the noise, no noise on cold start or if it sits for 10 minutes. The engine has a high compression head, 280 cam, nylon 7 1/2 degree cam gear, distributor and a KC Warford. It doesn't matter if the trans is in neutral and warford in gear or trans in high and warford in neutral, I have grounded out plugs and it makes no difference in the noise. The noise came on slowly and is getting worse but it goes away completely after a short time and runs and drives great. Also if it doesn't get up to temp it won't do it. If I had hair I would be pulling it out, any help would be greatly appreciated.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Strange - Hillsboro, MO on Monday, September 25, 2017 - 08:42 pm:

Piston slap?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, September 25, 2017 - 09:24 pm:

Piston slap would be more noticeable when starting cold or when pulling hard such as up a steep hill.

Perhaps the noise is related to oil? It takes a few seconds for the oil to be splashed all over the engine after starting. Maybe something is loose and after the oil starts flowing, the knock diminishes.

Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Monday, September 25, 2017 - 11:06 pm:

Things like piston slap and loose wrist pins would make noise when the engine is cold and it only makes the noise when hot and sets for a while. Norm, I agree that it sounds like the noise goes away after it gets oil, but why doesn't it make noise after it sits and cools off?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Vern (Vieux Carre) on Monday, September 25, 2017 - 11:12 pm:

" but it goes away completely after a short time and runs and drives great"

Sticking valve? The question is: Does the engine have full power before the noise goes away?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Davis on Monday, September 25, 2017 - 11:46 pm:

Could it be a flake of carbon in one of the cylinder heads or maybe on one spark plug that glows when the engine is hot causing pre ignition knock in one cylinder. just a shot in the dark.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Davis on Monday, September 25, 2017 - 11:50 pm:

Could it be a flake of carbon in one of the cylinder heads or maybe on one spark plug that glows when the engine is hot causing pre ignition knock in one cylinder. just a shot in the dark.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Tuesday, September 26, 2017 - 02:39 am:

I have heard of model Ts having that in between time kind of symptom when the small cam bearing was used on a cam requiring the larger bearing. Something about the cam floating fine when warm, and sticking slightly when cold. But in that in between temperature wanting to travel back and forth resulting in a knock. The thing about the wrong cam bearing is that there are so many variables on forces pushing the cam forward, and other forces pushing the cam back, that it seems no two exhibit quite the same symptoms. Note, the exact straightness of the cam grind, versus the wear on the cam lobes, pushing against the lifters, and how they do or do not rotate, all changes the cam's desire for forward or back. The timing gears also have both forward and backward pressures depending on speed and load.

Probably not the issue, but something to look for.

I have had two T engines with knocks that proved to be wrist pins. Both traced to a defective clamping bolt or rod end. Both knocked at all kinds of conditions and loads. I never could sort out a good diagnostic "knocks when (?)". One, a speedster, several times, I could have sworn was ready to throw the stinking rod right through the block doing 70 mph in Muncie overdrive. Both speed and load. A few seconds later? Quiet as the proverbial mouse. Didn't even have time to pull off the freeway. Back up to 70, stayed quiet. About a dozen such episodes of that was driving me nuts.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Tuesday, September 26, 2017 - 10:26 am:

Thanks guys, Jim, I have looked in the cylinders with a boroscope and there is little to no carbon and it runs smooth and strong with or without the noise. Wayne, I have been wondering about the cam bearing but my thought is that the screw that locks the bearing into position should hold it in one place. Any idea on how to check for bearing movement without pulling it apart?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cameron Whitaker, Oklahoma City on Tuesday, September 26, 2017 - 11:28 am:

My T had the same problem. I have tired babbitt, so I thought for sure it was a rod. Quite a knock when it sat and idled. Let her warm up and get to speed, and the knock disappeared. I checked the rods, but they were all within tolerance.

Turns out it was excessive camshaft endplay. This is a common problem on worn engines. I installed one of those camshaft endplay kits from Snyders, and the knock was gone!

I don't think that excessive camshaft endplay is really a big problem. It's just annoying as heck.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Wednesday, September 27, 2017 - 12:11 pm:

Looks like the timing cover will have to come off. It will be a week or so before I can do that, I will let you know what I find.


Top of pagePrevious messageNext messageBottom of page Link to this message  By gene french on Wednesday, September 27, 2017 - 02:57 pm:

Dennis:
you may want to check to see if a piston(s) is hitting the cylinder head or head gasket ...you did not state which type high compression head you have ...I have seen 4 instances where pistons hit the middle 2 cylinder chambers on the Z head ...this occurred after the engine heated and went away when cool ...always an optimist...gene french


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Wednesday, September 27, 2017 - 04:51 pm:

Gene F's idea is a good one. Such a knock would sound different than some other types knocks. The problem with not hearing it first hand becomes apparent.

As for the possible idea of a floating cam knock, a couple more things.
Essentially, Ford used two different camshafts, with matching front bearings through all the years. The middle bearing stayed the same throughout. Here, I may show very well how I am not always as smart as I sometimes like to think I am. Some of these details, I am not sure of.
I think the first (except for a few extremely early maybe?) style was the longer bearing which ran against the shorter front cam lobe. On these, the front cam lobe is roughly the same size as the other seven lobes. Somewhere in the '20s (I have heard about '24, but do not know), and for reasons I have not heard, Ford changed both the front cam lobe and the bearing. The bearing became shorter, and the cam lobe became longer. In this newer variation, the front lobe still runs against the back of the bearing in order to establish front to back placement. But the lobe has to be longer in order to establish that position.
If I understand all of this as well as I think I do, it should not be possible to use the earlier bearing on the later cam because the longer bearing would never fit in the shorter space between the gear and the front lobe. The problem comes along when an earlier cam with the longer space is used with a later shorter bearing. That goes together just fine. However, with the shorter bearing, and not having the longer cam lobe, it allows the camshaft to float forward. The cam gear can in that process hit the front cover, push back and then hit against the bearing. It also may find imperfections in the cover itself and hit those while rotating, that it otherwise should not be able to reach had it been held back by the bearing like it was supposed to be.
Those forces I previously mentioned, that some push forward, others backward, can (at some rpms) cause the camshaft to knock continuously for awhile making a noise very similar to a loose rod bearing.
It is a bit awkward, but you may be able to tell if you have a short bearing on a long-bearing camshaft by looking up through the pan inspection cover. I don't have any pictures available, but the front bearing and the front lobe need to almost touch each other. The space allowed by having the mismatched bearing is only about a quarter inch. That is all it takes make a pretty good knock. You may also need to check in the timer and check its position. (You probably cannot grab the end of the shaft and move it without a lot of grip. Not rotating, there would be a lot of resistance to movement by a few springs pushing down.) IF the camshaft is back where it should be, you may be able to tell through the inspection cover by sticking your index finger between the cam lobe and bearing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Wednesday, September 27, 2017 - 05:28 pm:

Just sitting here thinking about it. The camshaft floating forward could perhaps also contribute to some of those common mysterious ignition misfires, also known as "sometimes" running rough. The roller would also move forward with the camshaft. Years ago, I had an original after-market roller timer that ran the roller offset back from the Ford and most after-market timers. I had not noticed this minor difference. I used the best most perfect roller I had, not realizing that it was the common wrong one (I didn't have the right one anyway). That silly thing drove me nuts for a couple years. Sometimes, it ran perfectly. Other times, it would dead miss on one, and sometimes two, cylinders. Which cylinders were missing? Kept changing. Drove me nuts (repeated for effect). I checked everything again and again and again. Everything except that roller versus track position. One day, I pulled the timer (for about the fifteenth time), and noticed in the fresh (from just a few days earlier) white grease, that the roller was only running on the edge of the track. Careful measuring showed the problem. THAT timer was different. The roller running just on the edge did not make a reliable contact causing the coils to misfire.
If a camshaft floated forward nearly a quarter inch? It could have a similar effect by moving the roller forward. With a New Day timer, it could make the wear and destruction of the timer and'or brush much worse. With those, the plastic timer would be trying to do the job of the front cam bearing to hold the camshaft back.

Now back to the "what is this knock" theme of the thread. But odd ignition issues could maybe help with diagnostics.

Good luck!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Monday, October 02, 2017 - 09:28 pm:

Update- So I had time to drop the pan and pull the head, everything looks great. I found nothing that even remotely looked like a problem, the cam has about 5 to 8 thousands end play and the spec is 4 thou but 4 thou clearance end play couldn't make the kind of thump that it has and the clearance would get smaller with heat not larger. Any ideas? It also has slingers where the magnets use to be and they are tight and not cracked or damaged in any way, I also put the head on with no gasket and turned it over with no interference. If I had any wits I would be at the end. Thanks, Dennis


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Matthiesen on Tuesday, October 03, 2017 - 02:44 am:

Dennis, You said that you have distributor on you 26 T engine. I would check the distributor drive gears for odd wear patterns to see if they might be binding a little when hot. Also check the distributor shaft to see if it runs true in the distributor housing and the bearings are OK, if bearing equipped, instead of bushings.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Tuesday, October 03, 2017 - 02:54 am:

The worst knock I ever heard, turned out to be a small dent in the engine pan (not a model T). A connecting rod was hitting the dent every time it went around.
Loose rods and main bearings are what they are, and progress quickly to major disaster.
Other things include loose iron timing gears (I used to be almost famous for ignoring those once I figured that was all it was).
I did see an inside oil tube that was being hit by a connecting rod. Made a lot more noise than one would expect. I have also heard of a connecting rod hitting a long pan inspection cover bolt.
Another one that drives people crazy. The crank handle sliding back and allowing the ratchet to hit the crank pulley pin. Very common if the little spring that is supposed to be holding the handle forward when not engaged is not properly installed.
And, of course, the wrist pin is still in play.

Really listening to an engine seems to be becoming a lost art. And, it is not without certain risks (like sticking your ear into the fan while trying to hear a cam bearing, or your elbow onto a firing spark plug). It helps if you can have someone used to doing this walk you through it a few times. There are strange noises to be heard that are quite normal. Knowing what is or is not normal, is the hard part.
The two primary approaches to this, are the medical, and the mechanical. If you can get your hands on an old stethoscope, that should work great. The old mechanic's trick is a long screwdriver, or steel rod. I use the old early Ford V8 radiator screwdriver my dad had used for a decade before I was born (he never had an early Ford V8, just the screwdriver, and only for this purpose). I like it because it was what I learned on, it works well, and the handle is somehow comfortable pressed against my ear. I have used steel rods (I cushion the rod with my thumb between the rod and my ear), or a piece of tubing (like fuel line rubber hose), in a pinch. By the way, the tubing works better for locating exhaust and sometimes even intake leaks.

Very important warnings! Poking around a running engine, heavily distracted by trying to sort out a dozen different noises, trying to think what they all mean, is a recipe for disaster! BE VERY CAREFUL with every move you make. A tube stuck in the wrong place with the other end stuck in your ear could suck, or blow your eardrum out! Steel rods or long screwdrivers can get caught in fan-belts, hit by spinning fans, launched into your ear, or the car's radiator. And unexpectedly touching the ignition wire can be quite unpleasant (although, it generally will not harm you, and I have been known to touch them deliberately as a joke a few times).

Any internal combustion engine, with all its attending accoutrements, is a cacophony of noises. Whirring, banging, clanging, vibrations, sucking noises, explosions, all transmitting throughout the various blocks, castings, and brackets. However, the loudness dissipates as it travels, getting more quiet by the inch. However, those castings also try to fool you. some types of castings carry sound better than others. Harmonic intersections alter the noise. Still, one can narrow down what you hear to where it comes from, and with practice, if it sounds right.
The detonating charge in the cylinder sounds like a minor knock. That is normal. Different kinds of bearings (ball bearings, Babbitt, brass bushings) usually make a whirring sound. Sometimes with a ticking sound added in, usually depending on a shifting load with each turn or two.
Not many things should sound like a hammer hitting a heavy block. At least not good things.

Good luck! And please, be careful.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Wednesday, October 04, 2017 - 01:50 pm:

I may have found my noise. The cam gear was a little loose, I can't see how a nylon gear can make a rod knock sound but I will find out when I get the parts to put it back together if that was my noise. I will let you know what happens.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger - Wyoming on Wednesday, October 04, 2017 - 05:06 pm:

I will bet you found it...and good thing you did


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Wednesday, October 04, 2017 - 06:09 pm:

Fingers crossed!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Friday, October 06, 2017 - 12:49 pm:

Well it seemed like a good idea at the time but the loose timing gear was not my noise, as a matter of fact I think it may be worse. At this point all I can think of is possibly a cracked or broken piston, so when I have the time it will have to come apart (might be a little while before I get to it). I will let you know what I find. Thanks for your help and ideas.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Prince Madras, Oregon on Saturday, October 21, 2017 - 11:20 pm:

I had some time today and I pulled the pistons, there is some scuffing on the pistons and they feel like there is not enough clearance ( haven't measured yet) and the piston pins are tight. I know that these are an issue but I don't see how that could cause the noise that I have. I hope to have time to do some measuring next week. Any ideas? Thanks, Dennis


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevada Bob Middleton on Sunday, October 22, 2017 - 12:20 am:

Got a model A doese the same thing
Been that way for 20 years runs just fine
I figured Im gonna leave it alone runs to darn good


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem S.E. Michigan on Monday, October 23, 2017 - 10:57 am:

Dennis,

A tight wrist pin can definitely make that noise. It can even lock up your engine if it totally seizes.


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