The Ford Barn

ModAfan · 06-26-2016, 10:56 AM

My ’28 Tudor developed a knock of some kind recently. There is no knock on startup or until I am into a ride for five or ten minutes. The knock starts slowly, then it gets worse as the engine gets hotter. The knock happens only on acceleration. If I retard the spark (until the lever is about 1/4” from the retard stop) the knock goes completely away. If I advance the lever, the knock get’s really pronounced. There is no knock at idle, either on startup or when the engine is hot after a trip.

Any ideas? Thanks.

Patrick L. · 06-26-2016, 11:06 AM

Can you get this knock while sitting still with the hood open ? I'm wondering if you could try to locate it.

George Miller · 06-26-2016, 11:12 AM

Quote:

Originally Posted by ModAfan

My ’28 Tudor developed a knock of some kind recently. There is no knock on startup or until I am into a ride for five or ten minutes. The knock starts slowly, then it gets worse as the engine gets hotter. The knock happens only on acceleration. If I retard the spark (until the lever is about 1/4” from the retard stop) the knock goes completely away. If I advance the lever, the knock get’s really pronounced. There is no knock at idle, either on startup or when the engine is hot after a trip.

Any ideas? Thanks.

My guise loose center main. You should be able to get the knock, by speeding up the engine with the spark lever down. Short out number 2,3 cylinder and see if that changes the sound.

PC/SR · 06-26-2016, 12:16 PM

What George said. Center main getting loose. Do the tests. Adjust it early and all will be well.

Tom Wesenberg · 06-26-2016, 02:08 PM

Center main was also my first guess.
If you need to take the engine apart it would be wise to add a counterweighted crankshaft, or have weights added to your crankshaft.

jfreddie · 06-27-2016, 09:47 PM

Sponsored Links (Register now to hide all advertisements)

Amen, Tom!

ModAfan · 06-28-2016, 09:00 AM

Many thanks for all of your comments.

Patrick L., The noise seemed to come from everywhere when I idled the engine with the spark advanced.

I am going to try to drop the oil pan this week to see what I can see.

George Miller · 06-28-2016, 09:13 AM

Quote:

Originally Posted by ModAfan

Many thanks for all of your comments.

Patrick L., The noise seemed to come from everywhere when I idled the engine with the spark advanced.

I am going to try to drop the oil pan this week to see what I can see.

Just try shorting out 2,3 plugs then you will know for sure.

06-26-2016, 10:56 AM	#1
ModAfan Senior Member Join Date: Jul 2014 Location: Near Boston Posts: 135	Odd knock My ’28 Tudor developed a knock of some kind recently. There is no knock on startup or until I am into a ride for five or ten minutes. The knock starts slowly, then it gets worse as the engine gets hotter. The knock happens only on acceleration. If I retard the spark (until the lever is about 1/4” from the retard stop) the knock goes completely away. If I advance the lever, the knock get’s really pronounced. There is no knock at idle, either on startup or when the engine is hot after a trip. Any ideas? Thanks.

06-26-2016, 11:06 AM	#2
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Odd knock Can you get this knock while sitting still with the hood open ? I'm wondering if you could try to locate it.

06-26-2016, 12:16 PM	#4
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,285	Re: Odd knock What George said. Center main getting loose. Do the tests. Adjust it early and all will be well.

06-26-2016, 02:08 PM	#5
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Odd knock Center main was also my first guess. If you need to take the engine apart it would be wise to add a counterweighted crankshaft, or have weights added to your crankshaft.

06-27-2016, 09:47 PM	#6
jfreddie Senior Member Join Date: Jan 2015 Location: anchorage, alaska Posts: 119	Re: Odd knock Sponsored Links (Register now to hide all advertisements) Amen, Tom!

06-28-2016, 09:00 AM	#7
ModAfan Senior Member Join Date: Jul 2014 Location: Near Boston Posts: 135	Re: Odd knock Many thanks for all of your comments. Patrick L., The noise seemed to come from everywhere when I idled the engine with the spark advanced. I am going to try to drop the oil pan this week to see what I can see.