The Ford Barn

Bascomanny · 09-07-2015, 09:14 AM

Pre ignition knock

I have a completely rebuilt engine, everything new. It sounds great but when I put a load on it, it starts pinging, like a desel engine. I have changed the distributor, the timing, put high octane fuel. I still have the knock. Does anyone have a suggestion. Please help. Thank you

marc hildebrant · 09-07-2015, 09:23 AM

Is the head a standard Model A ? If so, then the ignition timing must be wrong and much to advanced.

How did you time the ignition ?

Marc

mrtexas · 09-07-2015, 09:29 AM

check timing with timing light

Patrick L. · 09-07-2015, 09:52 AM

Do you think the noise is pre-ignition or detonation[ spark knock] ? They are 2 different animals.
What cylinder head are you using ?
What are you using to set the ignition timing ?
Where do you keep the spark lever ?
Do you retard the spark when it starts making this noise ?

I'm wondering if there is something else wrong with it.

katy · 09-07-2015, 10:06 AM

Quote:

Do you think the noise is pre-ignition or detonation[ spark knock] ? They are 2 different animals.

Patrick, can you explain the difference.
Tnx, Ken

Mitch//pa · 09-07-2015, 10:19 AM

Sponsored Links (Register now to hide all advertisements)

https://en.m.wikipedia.org/wiki/Engine_knocking

BILL WILLIAMSON · 09-07-2015, 11:20 AM

Pre-ignition is like when Leaded Gas went away & Yo' Car would "DIESEL" & you couldn't get the dang thing stopped!
I had a '68 Datsun P.U, with a 2800 Mustang V-6 & C-4 automatic. Ran out of gas, poured in a gallon of Coleman Fuel to get to the station, PINGED, RATTLED, beyond belief. Couldn't get it SHUT OFF! As a last resort, plugged the tail pipe with a red shop rag & a screwdriver & held it there.
Almost finished mowing my lawn, once, & PFFFFT!--Did you know that a BRIGGS would run on ENERGINE CLEANING FLUID???
Bill W.

Tom Wesenberg · 09-07-2015, 11:40 AM

In the 60's I ran out of gas and only had some Coleman lantern fuel in the trunk. I used a quart to make it to the gas station, and as Bill said that engine sounded like a popcorn machine on steroids.

My 28 Phaeton had a very bad pinging problem with the slightest push of the gas pedal. This was on a completely stock engine, and with proper timing. I finally learned that it was caused by just and crud packed into the rear of the cooling chamber, which caused a hot spot on the cylinder. This was a good lesson to remove the head on an unknown engine and make sure it's clean inside. The engine had newer green paint and looked clean on the outside, so I pulled the pan to check for sludge and checked the bearings for play. It was good, so I just assumed the cooling system was also clean. BIG mistake!

09-07-2015, 09:14 AM	#1
Bascomanny Junior Member Join Date: Aug 2015 Location: Coos Bay, Oregon Posts: 3	Pre ignition knock Pre ignition knock I have a completely rebuilt engine, everything new. It sounds great but when I put a load on it, it starts pinging, like a desel engine. I have changed the distributor, the timing, put high octane fuel. I still have the knock. Does anyone have a suggestion. Please help. Thank you

09-07-2015, 09:23 AM	#2
marc hildebrant Senior Member Join Date: May 2010 Location: Cape Cod Posts: 1,128	Re: Pre ignition knock Is the head a standard Model A ? If so, then the ignition timing must be wrong and much to advanced. How did you time the ignition ? Marc

09-07-2015, 09:29 AM	#3
mrtexas Senior Member Join Date: May 2010 Location: Sugar Land, TX Posts: 4,395	Re: Pre ignition knock check timing with timing light

09-07-2015, 09:52 AM	#4
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Pre ignition knock Do you think the noise is pre-ignition or detonation[ spark knock] ? They are 2 different animals. What cylinder head are you using ? What are you using to set the ignition timing ? Where do you keep the spark lever ? Do you retard the spark when it starts making this noise ? I'm wondering if there is something else wrong with it.

09-07-2015, 10:19 AM	#6
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: Pre ignition knock Sponsored Links (Register now to hide all advertisements) https://en.m.wikipedia.org/wiki/Engine_knocking

09-07-2015, 11:20 AM	#7
BILL WILLIAMSON Senior Member Join Date: Dec 2010 Location: FRESNO, CA Posts: 12,560	Re: Pre ignition knock Pre-ignition is like when Leaded Gas went away & Yo' Car would "DIESEL" & you couldn't get the dang thing stopped! I had a '68 Datsun P.U, with a 2800 Mustang V-6 & C-4 automatic. Ran out of gas, poured in a gallon of Coleman Fuel to get to the station, PINGED, RATTLED, beyond belief. Couldn't get it SHUT OFF! As a last resort, plugged the tail pipe with a red shop rag & a screwdriver & held it there. Almost finished mowing my lawn, once, & PFFFFT!--Did you know that a BRIGGS would run on ENERGINE CLEANING FLUID??? Bill W. __________________ "THE ASSISTANT GURU OF STUFF" Last edited by BILL WILLIAMSON; 09-07-2015 at 01:12 PM.

09-07-2015, 11:40 AM	#8
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Pre ignition knock In the 60's I ran out of gas and only had some Coleman lantern fuel in the trunk. I used a quart to make it to the gas station, and as Bill said that engine sounded like a popcorn machine on steroids. My 28 Phaeton had a very bad pinging problem with the slightest push of the gas pedal. This was on a completely stock engine, and with proper timing. I finally learned that it was caused by just and crud packed into the rear of the cooling chamber, which caused a hot spot on the cylinder. This was a good lesson to remove the head on an unknown engine and make sure it's clean inside. The engine had newer green paint and looked clean on the outside, so I pulled the pan to check for sludge and checked the bearings for play. It was good, so I just assumed the cooling system was also clean. BIG mistake!