Noise in my new 29 a engin
 

ok guys I am new at this, but hear we go! I have done a complete rebuild of my 1929 ford model a engine! it runs great sounds real good until I get it warmed up & on the highway in third gear at what I am going to call a cruse, 35 mph or so. not giving it any gas & not letting off of it either! I get a noise I don't like & don't think is normal! at this point I can retard the spark lever & it almost goes away! can't think it is spark knock ! it sounds too much like something mechanical! tried removing the plug wires one at a time & it makes no difference in the sound of the engine, so don't think it is rod,main, or piston! it has been bored 100 over new pistons, rings & valves have been re done. Babbitt is good & crank has been replaced. oil pressure is good, I would like more, but that is what they say it should have, thought pistons might be touching the head, so I scoped the cylinders & find no evidence of this happening! this thing has me barking at the moon! has any body got any ideas? I need help

Re: Noise in my ney 29 a engin
 

Can you only hear the noise while in 3rd gear and going down the road after warm up or does it continue to make the noise while stopped after it is warmed up?
If the noise persists while stopped have you tried listening to the motor with a mechanics stethoscope to narrow the location down?

Re: Noise in my ney 29 a engin
 

How new is the engine, is it stock, or modified, retarding the spark is a way to quiet a loose bearing, did it always have the noise, or is it new and getting louder
louder cold or after hot?

Re: Noise in my ney 29 a engin
 

Now you've done it! :) Welcome to the Barn!

Re: Noise in my ney 29 a engin
 

X-2 wecome! It would help to know you location as someone could listen and guide you on the noise! Clubs in your area would be helpful also.

Re: Noise in my ney 29 a engin
 

It's really easy to forget to put in the plunger and spring in the timing gear cover.

Re: Noise in my ney 29 a engin
 

When you are running at 35mph where is the spark lever set?

Bob

Re: Noise in my ney 29 a engin
 

it is the loudest in 3 rd gear on the cruse! it will do it after it is warm at idle but not as bad! it gets quitter even at idle when you retard the timing

Re: Noise in my ney 29 a engin
 

I typically run it at full advance when at road speed, but when you retard the advance the noise quiets down, almost gone

Re: Noise in my ney 29 a engin
 

I put a new plunger & spring in to keep pressure on the cam!

Re: Noise in my ney 29 a engin
 

"Possibly" loose flywheel bolts?
Pop off the starter & with a screwdriver in the flywheel teeth, see if it rotates back & forth an 1/8" or so.
Bill W.

Re: Noise in my ney 29 a engin
 

maybe 100 miles! it is stock other than being bored 100 over, plastic gaged all the bearings & they run from 1.5 too 2 ish, Babbitt is in real good condition. as I Sayed earlier, removing the plug wires one at a time makes no change in the sound of the engine. if it was a rod or piston I think it would show up on removing plug wires one at a time!

Re: Noise in my ney 29 a engin
 

Get on a slight incline so the engine has to work in 3rd gear.

Retard spark lever until you feel a loss in power.

Advance it slightly, this is where you should be running at on the flat.

All you do with over advance is pound the babbit out.

The full window of advance is 40 degrees, dunno why Henry put that much in fer....

The engine sure don't like all of it.

Re: Noise in my ney 29 a engin
 

Bill I thought of that but I tightened them my self & put the safety wire in my self. I will look at this again because I am planning to remove the transmission & replace all the bearings & stop it from dripping oil this winter. this thing is about to get the best of me!

Re: Noise in my ney 29 a engin
 

Did you check rods for twist, Bend, and Off Set?

How much does the wrist pins have, for clearance.

Herm.

Re: Noise in my ney 29 a engin
 

Did you check the end play on your crankshaft? Did you check the backlash on your cam gear? Check the backlash on your rotor when the distributor is in the hole? What about the intermediate shaft between the oil pump drive and the distributor? Distributor shaft and sleeve? Check for wear in those areas. Take pictures.

Re: Noise in my ney 29 a engin
 

Pooch I will try that! what is the general thought on the automatic timing device that just does away with the spark control lever! timing is adjusted in accordance with engine rpm

Re: Noise in my ney 29 a engin
 

They seem to have good results with a stock low compression head, have heard it does not work that well with a high compression head. You shouldn't ever need to go full advance on your spark lever.

Re: Noise in my ney 29 a engin
 

Kohnke did not check for twisted or bent rod, generally they all looked the same, laid out flat, but that is about as far as I went there. as for wrist pin clearance, the machine shop took care of all that I presume when they put in the new wrist pin bushings, they are supposed to be good & I trust them!

Re: Noise in my ney 29 a engin
 

denniskliesen! they are a bit pricy but I was wondering if it would be worth the investment? I am running pretty much stock

Re: Noise in my ney 29 a engin
 

dennisklisen cam & crank gears are in real good shape & seem to mash together real nice & not much if any slack. the distributer gear is in real good shape & I replaced the intermediate gear that runs oil pump & distributer. I actually did not check end play on crank shaft because the main had good Babbitt on the thrust washer, seems as though I had just a bit of end play in the crankshaft as I was messing with the fly wheal, not much as I can remember!

Re: Noise in my ney 29 a engin
 

hay guys how do I post a picture on hear? I like you guys to see what I have been working on!

Re: Noise in my ney 29 a engin
 

will get back at this tomorrow ! I just noticed it is past my bed time! thanks guys! later

Re: Noise in my ney 29 a engin
 

Kohnke! just reading your post again & got too wondering? is there offset built into the rods? or is this just something too look for that could be wrong?

Re: Noise in my ney 29 a engin
 

The scoops on the rod caps need to have the open side face the camshaft. The caps should be matched to the rod by the stamped number, then the arrow on the piston, if there is one, points forward.

Re: Noise in my ney 29 a engin
 

To post pictures, click on the Go advanced box, then click on the paper clip icon and you're in business. Simple.

Re: Noise in my ney 29 a engin
 

100ih! the pistons came from Snyder's & they had no marking on tem & the machine shop said that they would work either way! as for the rods & caps, I kept them together so I know that they match & I do have the dipper the right direction! I really think the GREMLINS have got me!

Re: Noise in my new 29 a engin
 

Post number 10 reminded me of when I bought a new plunger and spring I had a knock as you do and found the new spring was very weak. Put an original spring in and the knock was gone. Just a thought as the new springs may be stronger today.

Re: Noise in my new 29 a engin
 

With no arrow indicating front, it might not matter. On the mod. A, many were slotted on one skirt, those had to have the skirt oriented correctly. I don't remember which way, but if the machinist installed the rings and piston and rod assemblies he no doubt was familiar with the issue. I must add that I agree with the post about not advancing the spark to the full stop position. I go with just enough advance to get satisfactory performance, more is not better, just hard on the crank & bearings.

Re: Noise in my new 29 a engin
 

pinball,

I see you're in northerm Missouri from your avarta. I'm down St. Louis way and I do Model A work. As Herm said it could be anything from a wrist pin to rod.... or something else internal. If there's someone near you that did the engine I would have them listen to it and see what their diagnosis was. Did they do the babbitt?
If you need additional help and diagnosis drop me a PM. We can chat and go from there.

Key at this point is carefull diagnosis without doing any further damage. Stuff happens so even with new pistons, etc things can go wrong. Good news is it can be fixed one way or another!
Larry Shepard

Re: Noise in my new 29 a engin
 

Do not run with your spark fully advanced. You do not need an auto advance. Find the sweet spot for your engine and learn to drive it as it was designed. Most times, if the car is timed right, your spark lever at about 9:00 should be fine for cruising.

Re: Noise in my ney 29 a engin
 

That could be it.

Re: Noise in my new 29 a engin
 

I've got a few questions...

how does a higher compression head alter the operation of a gyro style advance on the distributor shaft?


How can you effectively measure the optimum 10 degrees of timing for each 1000 rpm with a quadrant lever?

If too much timing advance causes center main bearing failure and the highest load on the engine is during acceleration how can you effectively advance the spark manually during acceleration without going into the 'danger' zone?

why did Ford immediately use mechanical flyweight timing advance in model B distributor along with the host of other design revisions with the model B?

Re: Noise in my ney 29 a engin
 

No Mr. Pinball, there should be NO off set in the Rods.

Wrist pins should not have less then .000-03 to not over .000-50 tenths of a thousandths clearance.

Herm.

Re: Noise in my new 29 a engin
 

I had one of those, after rebuilding everything sounded great but after 1000 miles it started to overheat going through the mountains then that little noise started , it seemed to go away under slight power and was most noticeable under no power or float. I changed a lot of stuff but never really found the source, I was left with the belief that it was the cam gear, had the engine apart and could see that the tops of a couple pistons had hit the gasket but after getting it back together the noise was still there, however the noise only started after the engine ran a mile or so so I left well enough alone and it never got any worse.

Re: Noise in my new 29 a engin
 

Barry B. if you ever find out what the problem is, please let me know! it sounds as though we have just about the same problem! the part that gets me is when I retard the spark the noise quiets down, almost goes away, not completely, but almost I get a bit of noise when I rev the engine, but not as loud as when at road speed

Re: Noise in my ney 29 a engin
 

Kohnke wrist pins came new with pistons! put new wrist pin bushings in the rods & they were honed to very snug fit, I double checked the pin keepers to make certain they were locked in place!

Re: Noise in my ney 29 a engin
 

From all the threads I've read the automatic timing advance works nicely.the only caveat is the curve isn't broad enough, easily solved by keeping your manual spark control hooked up but limited in travel to move the entire curve up and down with the lever.To set it up correctly requires peak advance timing,basically running the engine at high rpm and using a timing light and pointer to check that max advance does not exceed 30 degrees, then setting your lever limit to stop at that point..this allows you to retard the spark by hand if the condition requires it, yet never allow you to exceed max advance.

the benefit to automatic advance is correct timing during acceleration, a key to long center main bearing life...and instead of not being recommended, its a must for using a high compression head, due to the compression increase,the 'hammer effect' on the center main bearing during detonation caused by improper timing being greater than stock compression,higher compression accentuates the detonation effect.

Re: Noise in my new 29 a engin
 

Railcarmover, The head doesn't change the timing. The head changes the engine's need for certain timing. Generally, higher compression causes higher peak temp on compression just before ignition. This causes a faster burn, so the engine needs less ignition advance. A similar effect can happen with a cam, manifold, or exhaust change. Different cylinder filling at different rpm's makes the burn rate different, so different ignition timing may be needed.

The only way I know to measure a bob weight type advance at different rpm's is with a tachometer and a timing light.

Re: Noise in my new 29 a engin
 

I don't know if anybody mentioned it but it could be a loose timing gear--loose on the cam. I once had a knock that was driving me crazy and even though I was sure the timing gear was tight when I checked it I found it loose. When I tightened it and center punched the nut to make sure it wouldn't loosen the knock was gone. And in my case it only knocked after the engine had warmed.