The Ford Barn

Pete Fl/Wi · 01-07-2014, 02:04 PM

Tearing down an 8BA I bought for a spare engine. Hard to see in the picture but a small screw was dancing around on this piston. The screw was gone but left it's mark. I dont see it as a problem.
Pete

50flathead · 01-07-2014, 02:15 PM

Polish it out and go. Something got sucked in from who knows where.

50fordbob · 01-07-2014, 02:40 PM

I had a simular problem with my fathers 2000 Buick LeSabre. I took in to the dealer after it had cracked intake manifold replaced and was leaking again. They replaced a second manifold underneath the new one. Upon restart the engine knocked and was shut down. They pulled the head and found a small piece of metal that looked like a beat up roll pin. I went over and looked at it, the bore was fine and the piston looked better than the one in the picture. I agreed to putting it back together and thought it would be fine. Upon restart it still knocked. They pulled the piston and found a crack. With a new piston, rings,rod and bearings it was fine and still good when it was traded five years later. The 30 year GM line mechanic told me this was the second time he had run into this problem. Bob

deuce_roadster · 01-07-2014, 04:57 PM

I had identical marks on one of my pistons. I KNOW what caused it because it freaked me out to hear the sudden banging and I shut it down and took the head off. A wise friend said "look down your carb throat and see if the screws that hold the butterflies on the shaft are still there." Yep, one was missing, got blown out the exhaust. No real damage to the piston in my case, still running strong.

Mart · 01-07-2014, 06:21 PM

As you are tearing it down you will be able to inspect the piston from all angles. I had a really nice German flatty low mileage motor that swallowed something and made a sudden loud noise. The piston was more heavily indented than that one and when taken out was found to be cracked.

Yours looks like it is probably ok, but it would be good to inspect it properly.

Mart.

uncle max · 01-07-2014, 06:26 PM

Sponsored Links (Register now to hide all advertisements)

This is exactly why I use a special anvil to stake the choke and throttleshaft screws!

01-07-2014, 02:15 PM	#2
50flathead Member Join Date: Jul 2010 Posts: 54	Re: Someone lost a screw Polish it out and go. Something got sucked in from who knows where.

01-07-2014, 02:40 PM	#3
50fordbob Junior Member Join Date: Nov 2010 Location: Greenfield. In. Posts: 13	Re: Someone lost a screw I had a simular problem with my fathers 2000 Buick LeSabre. I took in to the dealer after it had cracked intake manifold replaced and was leaking again. They replaced a second manifold underneath the new one. Upon restart the engine knocked and was shut down. They pulled the head and found a small piece of metal that looked like a beat up roll pin. I went over and looked at it, the bore was fine and the piston looked better than the one in the picture. I agreed to putting it back together and thought it would be fine. Upon restart it still knocked. They pulled the piston and found a crack. With a new piston, rings,rod and bearings it was fine and still good when it was traded five years later. The 30 year GM line mechanic told me this was the second time he had run into this problem. Bob

01-07-2014, 04:57 PM	#4
deuce_roadster Senior Member Join Date: Oct 2011 Location: Shelton, WA Posts: 3,799	Re: Someone lost a screw I had identical marks on one of my pistons. I KNOW what caused it because it freaked me out to hear the sudden banging and I shut it down and took the head off. A wise friend said "look down your carb throat and see if the screws that hold the butterflies on the shaft are still there." Yep, one was missing, got blown out the exhaust. No real damage to the piston in my case, still running strong.

01-07-2014, 06:21 PM	#5
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,745	Re: Someone lost a screw As you are tearing it down you will be able to inspect the piston from all angles. I had a really nice German flatty low mileage motor that swallowed something and made a sudden loud noise. The piston was more heavily indented than that one and when taken out was found to be cracked. Yours looks like it is probably ok, but it would be good to inspect it properly. Mart.

01-07-2014, 06:26 PM	#6
uncle max Senior Member Join Date: May 2010 Location: SLC Utah Posts: 798	Re: Someone lost a screw Sponsored Links (Register now to hide all advertisements) This is exactly why I use a special anvil to stake the choke and throttleshaft screws! __________________ RIP Tyler... My Son, Helper & Best Friend. Feb '78 to Father's Day '10. www.97-express.com ~ [email protected]