Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 03-19-2017, 09:31 AM   #1
kenparker
Senior Member
 
kenparker's Avatar
 
Join Date: May 2010
Location: Van, Texas
Posts: 1,122
Default damaged piston what? why?

I am posting these questions for my friend and fellow Model A'er and FB'er? Hope he doesn't get mad at me.
Couple months ago we tore his engine down to find out why there was a major oil leak - front and rear. Turned out to be bad gaskets and seals. While into the engine we check all the clearances and they were sopt on .0015 to .00175. Replaced all gaskets and reinstalled his engine and adjusted the valves while we were into it. good news NO LEAKS.

Next chapter. On his way home in his A - about 15 miles, His engine started a loud clikcking noise. Like a loud chirping criket. Noise was coming from the center of the block as in # 2 or 3 cyl. Again, his engine came out of the car yesterday and we started tearing it apart to fine the cause of the chirping.

Discovery. Severe scraping on the side of #3 piston. See picture below. Two pictures showing each side of the piston. Also the Oil Ring was stuck - as in it would not rotate in its groove - and had to be puled out with pliers. The scraping had damaged the goove to the point it had wedged the oil ring in its groove.

Question to you engine gurus? What would have caused this damage? The engine was making no unessary noises before the first tear down.

Inquiring minds need to know. ken
Attached Images
File Type: jpg bills piston 1.jpg (44.0 KB, 295 views)
File Type: jpg bills piston 2.jpg (39.8 KB, 270 views)
kenparker is offline   Reply With Quote
Old 03-19-2017, 09:47 AM   #2
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 3,432
Default Re: damaged piston what? why?

I would expect the cylinder walls to have scratches as well. Material / debris broken off of that stuck oil control ring is a likely culprit. I have seen this type of failure in an engine that sat idle for a long time, and was started with dry cylinder walls.
__________________
Bob Bidonde
Bob Bidonde is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 03-19-2017, 09:49 AM   #3
Jacksonlll
Senior Member
 
Jacksonlll's Avatar
 
Join Date: Jul 2012
Location: Michigan-- Member of Oakleaf of MARC
Posts: 1,686
Send a message via ICQ to Jacksonlll
Default Re: damaged piston what? why?

My guess is that something sneaked in through a plug hole and did the damage. I bet the head has some witness marks.
Jacksonlll is offline   Reply With Quote
Old 03-19-2017, 10:20 AM   #4
Mitch//pa
BANNED
 
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
Default Re: damaged piston what? why?

It could have been many things incld a radiator issue. Take everything to a knowledgable place to determine the cause.
Mitch//pa is offline   Reply With Quote
Old 03-19-2017, 10:51 AM   #5
George Miller
Senior Member
 
George Miller's Avatar
 
Join Date: May 2010
Location: NC
Posts: 2,975
Default Re: damaged piston what? why?

I would say to close of a fit in the cylinder or to much slug around bore in the block. It was caused by to much heat. Maybe slow timing.
George Miller is offline   Reply With Quote
Old 03-19-2017, 10:54 AM   #6
Y-Blockhead
Senior Member
 
Y-Blockhead's Avatar
 
Join Date: Jul 2011
Location: Redondo Beach, CA
Posts: 5,817
Default Re: damaged piston what? why?

Sponsored Links (Register now to hide all advertisements)
It appears that it was seizing. Did the engine get hot? Was the piston dry when you pulled it? Did you ensure the pistons were re-installed in the same hole they came out of? Is there any metal transfer to the cylinder wall from the piston?

I can't see anything going down the spark plug hole and getting past the compression rings to do that on both sides of the skirt but who knows??
Y-Blockhead is offline   Reply With Quote
Old 03-19-2017, 10:57 AM   #7
Jim Brierley
Senior Member
 
Join Date: Jun 2010
Location: Temecula, CA
Posts: 4,066
Default Re: damaged piston what? why?

I agree with George Miller. Ford said .002" max clearance, today's pistons and higher speed driving need more. I bore to .003" and hone another .0005" as minimums, more on performance engines.
Jim Brierley is offline   Reply With Quote
Old 03-19-2017, 10:59 AM   #8
George Miller
Senior Member
 
George Miller's Avatar
 
Join Date: May 2010
Location: NC
Posts: 2,975
Default Re: damaged piston what? why?

I bore the same as Jim Says
George Miller is offline   Reply With Quote
Old 03-19-2017, 12:05 PM   #9
aonemarine
Senior Member
 
aonemarine's Avatar
 
Join Date: Dec 2013
Location: Delaware
Posts: 252
Default Re: damaged piston what? why?

Was it just gasket replacement or did you pop in a fresh set or rings while you were in there?
aonemarine is offline   Reply With Quote
Old 03-19-2017, 12:06 PM   #10
H. L. Chauvin
Senior Member
 
Join Date: May 2010
Posts: 4,179
Default Re: damaged piston what? why?

Per part of comment in reply #6:

"Did you ensure the pistons were re-installed in the same hole they came out of?"

Whether this was the primary cause or not, in re-installing pistons and connecting rods, we are involved with measurements in thousandths of an inch; former engine cylinder/ring wear; and human beings performing the initial re-bore of the block where all cylinders may not be 100% "exactly" alike.

FWIW: Always a good idea to provide small marks on tops of pistons and sides of connecting rods, e.g., from I thru IV on piston tops, and small l, ll, lll, llll, vee marks on sides of connecting rods.

Mechanical failures always occur for a definite reason:

If you would have had several "shop" spy cameras rigged up in your shop, you could re-play the video and possibly "see" the actual cause of the wear ..... maybe not enough water replaced in radiator or whatever ..... "hint", "hint" .... we might have to wait until next year for Model A parts suppliers to offer "shop" spy cameras for after-the-fact mechanical investigation.
H. L. Chauvin is offline   Reply With Quote
Old 03-19-2017, 01:39 PM   #11
Tom Wesenberg
Senior Member
 
Tom Wesenberg's Avatar
 
Join Date: May 2010
Location: Mpls, MN
Posts: 27,582
Default Re: damaged piston what? why?

As Mitch said, it could be any number of things.
I've seen identical damage from timing too advanced, and causing the engine to ping.
Of course the ping caused the piston to overheat and do the damage.
Tom Wesenberg is offline   Reply With Quote
Old 03-19-2017, 07:23 PM   #12
Kohnke Rebabbitting
Senior Member
 
Join Date: May 2010
Location: 60615,330th Ave.,Clare, Iowa, 50524
Posts: 1,457
Default Re: damaged piston what? why?

Jim and George are right. The only time you get piston galling like that is to tight of fit.

Never go by the instructions that come with the set of pistons !

Never under a .001 per inch. Just like main and rod bearings when new.

Herm.
Kohnke Rebabbitting is offline   Reply With Quote
Old 03-19-2017, 07:52 PM   #13
BillLee/Chandler, TX
Senior Member
 
BillLee/Chandler, TX's Avatar
 
Join Date: May 2010
Location: The sticks of east Texas
Posts: 474
Default Re: damaged piston what? why?

Engine is mine.

Quote:
Originally Posted by Bob Bidonde View Post
I would expect the cylinder walls to have scratches as well. Material / debris broken off of that stuck oil control ring is a likely culprit. I have seen this type of failure in an engine that sat idle for a long time, and was started with dry cylinder walls.
There is NO cylinder wall damage. Pictures below.

Quote:
Originally Posted by Jacksonlll View Post
My guess is that something sneaked in through a plug hole and did the damage. I bet the head has some witness marks.
No damage above oil ring. no damage on top of piston. No damage in head.

Quote:
Originally Posted by Mitch//pa View Post
It could have been many things incld a radiator issue. Take everything to a knowledgable place to determine the cause.
I suspect Ken is sufficiently "knowledgable".

Quote:
Originally Posted by George Miller View Post
I would say to close of a fit in the cylinder or to much slug around bore in the block. It was caused by to much heat. Maybe slow timing.
This engine was built by Berts in 1986. It has just under 6,000 miles. It has been hot in the past, but that has been solved for the past couple of years I have owned it. The other three pistons are perfect, and all four cylinders as well. No apparent problems before this showed up on my drive home from Ken's. The engine ran well and was at normal temperature all of that time.

Quote:
Originally Posted by Y-Blockhead View Post
It appears that it was seizing. Did the engine get hot? Was the piston dry when you pulled it? Did you ensure the pistons were re-installed in the same hole they came out of? Is there any metal transfer to the cylinder wall from the piston?

No, it did not get hot. No, the piston was not dry when removed. The first tear-down that Ken mentioned was only to replace gaskets and main bearing seals. The pistons were not removed at any time, hence could not have been put back improperly. As noted above, there is NO damage to the cylinder walls.

Quote:
Originally Posted by Y-Blockhead View Post
I can't see anything going down the spark plug hole and getting past the compression rings to do that on both sides of the skirt but who knows??


Agreed.

Quote:
Originally Posted by aonemarine View Post
Was it just gasket replacement or did you pop in a fresh set or rings while you were in there?
Only gaskets.

One suggestion from another of my local knowledgeable friends was a possible stuck wrist pin. We were looking closely at that when we removed the pistons and found no indication that that was the cause. The rod moved easily on the pin as well as the pin moving in the piston, completely equivalent to the other three pistons. There was no excess movement.

Regards,

Bill Lee

Photos show one of the other pistons, and the #3 cylinder. Very hard to get a decent picture of the cylinder, and it does not show well that there is NO damage in that cylinder.
Attached Images
File Type: jpg DSC_7942A.jpg (34.8 KB, 190 views)
File Type: jpg DSC_7933A.jpg (80.5 KB, 189 views)
__________________
Bill Lee
http://www.CedarCreekAs.org
BillLee/Chandler, TX is offline   Reply With Quote
Old 03-19-2017, 07:58 PM   #14
Mitch//pa
BANNED
 
Join Date: May 2010
Location: Bucks County, PA
Posts: 11,454
Default Re: damaged piston what? why?

Quote--It has been hot in the past, but that has been solved for the past couple of years I have owned it---quote


A hot running engine is a slow death.... very possibly it was not corrected soon enough
Mitch//pa is offline   Reply With Quote
Old 03-19-2017, 08:13 PM   #15
BillLee/Chandler, TX
Senior Member
 
BillLee/Chandler, TX's Avatar
 
Join Date: May 2010
Location: The sticks of east Texas
Posts: 474
Default Re: damaged piston what? why?

Quote:
Originally Posted by Mitch//pa View Post
Quote--It has been hot in the past, but that has been solved for the past couple of years I have owned it---quote


A hot running engine is a slow death.... very possibly it was not corrected soon enough
Agreed.

What is puzzling Ken and me is the COMPLETE lack of any damage to the cylinder itself. I would think that if this piston damage had been going on for a longer time than the last 15 miles I would have 1) heard it long before now, and 2)had significant evidence in the cylinder.

Really strange.
__________________
Bill Lee
http://www.CedarCreekAs.org
BillLee/Chandler, TX is offline   Reply With Quote
Old 03-19-2017, 08:42 PM   #16
H. L. Chauvin
Senior Member
 
Join Date: May 2010
Posts: 4,179
Default Re: damaged piston what? why?

Ken & Bill,

If you try a very accurate bore gauge to measure the top and bottom diameters of each of the four (4) individual cylinders, and accurately measure the external diameters of the four (4) pistons, these measurements may give a clue as to what happened.

Aluminum pistons will wear quicker than cylinder walls.

Takes a tight fit to cause wear like this whether caused by heat expansion or not.
H. L. Chauvin is offline   Reply With Quote
Old 03-19-2017, 09:30 PM   #17
George Miller
Senior Member
 
George Miller's Avatar
 
Join Date: May 2010
Location: NC
Posts: 2,975
Default Re: damaged piston what? why?

It was caused by heat, but that does not mean it was hot on the temp gauge. It means it was hot on that cylinder wall. I have seen it many times. Number 3 runs hotter than 1,2 any way. It could happen if you were running it faster than normal on a hot day, or pulling a long hill, spark retarded to much, or to lean which will make it run hot inside the engine. Or all of the above.
George Miller is offline   Reply With Quote
Old 03-19-2017, 09:47 PM   #18
George Miller
Senior Member
 
George Miller's Avatar
 
Join Date: May 2010
Location: NC
Posts: 2,975
Default Re: damaged piston what? why?

Quote:
Originally Posted by BillLee/Chandler, TX View Post
Agreed.

What is puzzling Ken and me is the COMPLETE lack of any damage to the cylinder itself. I would think that if this piston damage had been going on for a longer time than the last 15 miles I would have 1) heard it long before now, and 2)had significant evidence in the cylinder.

Really strange.
That kind piston damage does not hurt the cylinder wall most of the time. Some times a little of alum from the piston sticks on the cylinder wall, but you can hone it off. This is a common problem with the model a now days.

Last edited by George Miller; 03-20-2017 at 01:43 PM. Reason: spelling
George Miller is offline   Reply With Quote
Old 03-20-2017, 08:07 AM   #19
Jacksonlll
Senior Member
 
Jacksonlll's Avatar
 
Join Date: Jul 2012
Location: Michigan-- Member of Oakleaf of MARC
Posts: 1,686
Send a message via ICQ to Jacksonlll
Default Re: damaged piston what? why?

I think Miller and Blockhead have it. Just suppose there was no water in it by mistake? The temp gage would not show hot. Just hot air in there if no water. Then it ran for 15 min. Sounds possible.
Jacksonlll is offline   Reply With Quote
Old 03-20-2017, 08:42 AM   #20
Smurkey
Senior Member
 
Smurkey's Avatar
 
Join Date: Nov 2011
Location: Esko, MN
Posts: 257
Default Re: damaged piston what? why?

It would be coincidental, but maybe the dipper tray developed a hole. The oil would just run out of the tray as fast as the pump replaced it.

Just a thought...
Smurkey is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 02:30 AM.