Engine knock

[Harvey Bergstrom]

Hi everyone,
As I am getting serious about getting my T ready for parades and maybe even a tour this summer, it has to be the best it can be. Started working last summer on it and took the engine to a machine shop for a major overhaul. It was found to be all original. They rebored block, installed new aluminum pistons, new rods, cam bearings, mains were good yet as well as crank & camshafts. New SS valves & seats w/ adjustable lifters. After engine warms up, no knock at slow idle but at moderate idle, knock is there. While I hear knock, I short out one spark plug at a time, and find the noise to stop when no. 3 is shorted. While shorting no. 3, I can rev engine with no unusual sound at all only running on three cylinders. That should tell me the mains are OK. Has anyone had a new rod be bad in a rebuild you have done? I am at my Witt’s end. I know you guys will have some very good thoughts on this for me and am grateful for your responses! Happy Spring and safe driving!
Harvey Bergstrom

[Kerry]

Could be that the rods need to be checked for alignment, it is very easy to twist one when fitting wrist pin bolt if not done correctly.

[Craig Leach]

Hi Harvey,
I would be taking the inspection cover off & looking close at everything. This sounds like its just been rebuilt, could be many things that could
have been overlooked. Not knowing what was done there could have been something missed or not caught in the rebuild. Some have had issues
with wristpins to tight, old rod bolts sretched to the braking point or just something overlooked Sounds like you may have had someone rebuild
it for you. Have you asked them to check it out?
Craig.

[Jerry VanOoteghem]

I would be asking the rebuilder these questions.

[speedytinc]

Could be that the rods need to be checked for alignment, it is very easy to twist one when fitting wrist pin bolt if not done correctly.

Is your re-builder a well versed T guy? here are many special precautions to take, such as mentioned. Even new rods should be checked before installing. T motors require different skill sets than for small block chevys.

[TXGOAT2]

How many hours has the engine run since it was rebuilt?

What break-in procedure was used?

What type and grade oil was used?

Were you present when the engine was first started after the rebuild?

Was the engine provided with water or other coolant when first started?

Was the oil pan properly filled with a suitable oil?

Has the engine been checked for proper oil distribution?

[Les Schubert]

If the “knock” is a bit intermittent (not totally consistent) it is most likely camshaft end play by my experience.

[Mark Nunn]

If the “knock” is a bit intermittent (not totally consistent) it is most likely camshaft end play by my experience.

Les. I have the same knock and also suspect camshaft end play. Do you know of a way to fix or shim the cam bearing without removing the cam?

[speedytinc]

If the “knock” is a bit intermittent (not totally consistent) it is most likely camshaft end play by my experience.

Les. I have the same knock and also suspect camshaft end play. Do you know of a way to fix or shim the cam bearing without removing the cam?

Yes.
Remove the timing cover & put in a front thrust washer kit or make one yourself. Chaffins sells a kit. This kit is suggested/required when putting in a reground cam with an eliminated heel on #1 lobe.

However, shorting out #3 cylinder doesnt remotely point to this being OP's problem. I cured such a cam bearing knock once.
The knocking grew progressively louder over time. (constant)
The front lobe, via the natural forward pressure of a cam(non straight cut gears), moves forward. The lobe shaves the loose half of the cam bearing.
Creating a knock every revolution.

BTW the condition can be confirmed thru the inspection cover visually.

[Craig Leach]

Hi Harvey,
A quick word of caution you stated this was a recent engine rebuild? If the crank was fitted with a modern seal this could be a real can of
worms so be real sure that is the issue first. The modern seal will not like removing the timing cover & may have to be replaced with a rope
seal that is not always a fun thing to install. I spent 2 days on a relatives T to install the cam shim kit & the engine still knocks! We have
eliminated everything we could think of? Years later it's still running great just noisey? Checked everything to make sure rods, mains,
wristpins, gears, crank endplay. It still sounds like a cam noise?
Good Luck.
Craig.

[TXGOAT2]

A very slightly tapered crankpin might cause a knock that would respond to pulling the plug wire on that cylinder.

Could it be something back in the transmission?

[got10carz]

I drove to Harvey's place today, 190 miles round trip. What he said was true, #3 made a big difference, but #2 also made a slight difference in the knock. Without pulling the motor out and checking everything I went after the center main. 1 bolt had no torque to it, the other was tight. We removed. 006 of shim and are hoping for good results. We were short of gaskets so answer will come next week.
For payment I recieved the best ever. A 6 song melody on the concertina. Due to my Czech heritage and the only thing I can dance to is a polka or waltz that was worth way more than money.
Harvey Is a EXCELLENT concertina musician.
A wonderful day.

[Jerry VanOoteghem]

I drove to Harvey's place today, 190 miles round trip. What he said was true, #3 made a big difference, but #2 also made a slight difference in the knock. Without pulling the motor out and checking everything I went after the center main. 1 bolt had no torque to it, the other was tight. We removed. 006 of shim and are hoping for good results. We were short of gaskets so answer will come next week.
For payment I recieved the best ever. A 6 song melody on the concertina. Due to my Czech heritage and the only thing I can dance to is a polka or waltz that was worth way more than money.
Harvey Is a EXCELLENT concertina musician.
A wonderful day.

What a great experience!

[Scott_Conger]

whether it was a top-flight "T" shop or a sawdust-floor butcher shop that did the engine, I'd think that letting the shop diagnose and rectify a new rebuild is the right thing to do. Even finding a grievous error in the rebuild and then self-remedying it without express consent from the original shop would/should void any warrantee that it came with. That's a big and costly burden to bear if you find yourself on your own trying to get this right.

Don't get me wrong...I'm not maligning anyone involved in this project, but how much work can be done before the builder justifiably washes his hands of this thing and tells you that you now own the problem?

Please consider letting the guy make it right and get the biggest bang for your buck at this point.

[rickd]

Steve is the best Model T guy in our neck of the woods. Good job Steve.

[Harvey Bergstrom]

I think Steve got to the bottom of my issue with knock. I am surely blessed with so many thoughts and help with Model T related problems. Being new to the hobby, one needs all the advice he can scare up. I talked to the machine shop who did the rebuild and he said bring it in and he would look at it. No guarantee as time because of much work coming in there. I am thinking it was an error or oversight of there’s. As Steve stated, once I get Henry’s gaskets, will be anxious to hear what he sounds like. I’ll bet 99 dollars to 1 Steve resolved the issue. I’ll keep you posted.

[Harvey Bergstrom]

Another thought on the rebuilder. This guy is getting up there in years and has run a reputable business for 55 years and recently sold out but still works there full time. Another oversight that cost me to take the engine back out the day after I put the it back in, was when as I’m pouring coolant into radiator see dripping on the floor. Investigated only to find crack on manifold side of block. The first thing I told him to do before anything magnaflux the block. If that was overlooked, I can see another oversight on this center main as well.

[speedytinc]

I think Steve got to the bottom of my issue with knock. I am surely blessed with so many thoughts and help with Model T related problems. Being new to the hobby, one needs all the advice he can scare up. I talked to the machine shop who did the rebuild and he said bring it in and he would look at it. No guarantee as time because of much work coming in there. I am thinking it was an error or oversight of there’s. As Steve stated, once I get Henry’s gaskets, will be anxious to hear what he sounds like. I’ll bet 99 dollars to 1 Steve resolved the issue. I’ll keep you posted.

Debbie Downer here. Ill take that bet.
Finding a loose bearing cap is bad, but what caused the need for .006" shim in a new motor??
I ask myself: are the mains in alignment? Is the crank bent? What else was "neglected"?
Were this mine, I would tear it down & reassemble inspecting with a fine tooth comb.
This, in my mind, would eliminate future issues that are bound to come up.
Sorry, but Murphy & I are old acquaintances.

[NoelChico]

I've spoken to Harvey several times regarding this engine and car, and hope to finally meet him on tour this summer. He mentioned to me that the crank was removed for the cylinder boring, but he didn't believe new babbit was poured or bored as the original crankshaft was put back in. I expressed concern that tightening up the middle main would put a bow in the crank on every revolution and perhaps earn him membership in the 2 piece crank club. He told me that a single shim was removed from each side of the bearing but Steve was there. I was thinking that gives only .003 tightening. I also wondered how tight the other crankshaft bolts are that he cannot access. I agree that the original rebuilder should look at this engine before it's run again.

[Jerry VanOoteghem]

I sometimes have mixed emotions about taking something back to the place where it was rebuilt/repaired. On the face of it, it's the best route to take. However, I think you have to consider the severity of the problem and what led to it in the first place. If I sense an honest mistake in something that was otherwise sound, I'll take it back. But, if it's a series of problems that demonstrate incompetence, why give them another chance to mess it up. I'm not suggesting that either situation applies here. I'm speaking in generalities.

[ElGranadaT]

just had a very similar problem with my no. 1 piston - ended up being the piston wrist pin - as the aluminum piston heated up the hole got larger and the wrist pin knocked more -

[Harvey Bergstrom]

Hi everyone,
Today I got the gaskets on the pan & tapper covers and buttoned back up. Started Henry up and no more knocking like it was before. Found out Ford had a couple different cranks in 1924, and appears I have the lighter of the two. Bad news - I don’t know. This crank has run nearly 100 years in this engine ands hasn’t broke yet! My plan is to run with what it is, and if and when it breaks, put in a Scat or maybe another tear down next winter to keep me busy.
Thank you guys for your input!