The Ford Barn

700rpm · 06-02-2015, 10:34 PM

I've been struggling with what I perceived as an over-tight engine since the rebuild last spring. Here is the earlier thread on it:
http://fordbarn.com/forum/showthread.php?t=154688

Most theories came down to too tight of a clearance on the rings.

I finally pulled the pistons and checked my ring gap on the top two rings on all four cylinders, and they were all .020 ±, well within mfgr's specs (Hastings, from Snyder's). Piston clearance on all four was .004+, which also seems to be the consensus here and elsewhere on proper piston clearance. Tomorrow or the next day I’ll reassemble and drive it. I don’t know what else can be causing it to seize up when warmed up, except maybe -maybe!- it is still in the break-in phase. But I'm out of options and it's driving season, and since I found no serious damage inside, I'm gonna drive it! If there is a serious problem, I guess it will eventually show up.

Tom Wesenberg · 06-02-2015, 10:40 PM

Are the coolant chambers totally clean, especially the rear two on the drivers side?

That's where I find most of the rust and junk that accumulates.

700rpm · 06-02-2015, 11:33 PM

Quote:

Originally Posted by Tom Wesenberg

Are the coolant chambers totally clean, especially the rear two on the drivers side?

That's where I find most of the rust and junk that accumulates.

Yes. The block was hot tanked before the initial reassembly, and while there is some minor rust accumulating, I have run it only with a rust preventative and a tablespoon of water soluable oil since the rebuild, so the rust is minimal. When I get it running, I may use your vinegar treatment too. But it has shown no signs of overheating since the rebuild; it runs just about where it should, according to temp gun readings I've taken. Even cylinders 3 & 4. It's been a real mystery.

Tom Wesenberg · 06-03-2015, 12:13 AM

I agree, since the ring and piston clearances are fine, I see no reason for it to get tight and stop. If you have a temp gun, the next time it gets tight, I'd immediately take the temp of each spark plug base, and each cylinder just below the water jacket.

pooch · 06-03-2015, 02:25 AM

How is your gas flow?

Even if you are checking the air/gas ratio idling, it may be starving a little on running at high speed and causing the innards to overheat and expand.

I have always been told to make sure of no lean-ness on running in , and err on the side of richness .

Could you fit an exhaust temp probe and then be able to check for overheating while driving ?

James Rogers · 06-03-2015, 05:13 AM

Sponsored Links (Register now to hide all advertisements)

Quote:

Originally Posted by 700rpm

I've been struggling with what I perceived as an over-tight engine since the rebuild last spring. Here is the earlier thread on it:
http://fordbarn.com/forum/showthread.php?t=154688

Most theories came down to too tight of a clearance on the rings.

I finally pulled the pistons and checked my ring gap on the top two rings on all four cylinders, and they were all .020 ±, well within mfgr's specs (Hastings, from Snyder's). Piston clearance on all four was .004+, which also seems to be the consensus here and elsewhere on proper piston clearance. Tomorrow or the next day I’ll reassemble and drive it. I don’t know what else can be causing it to seize up when warmed up, except maybe -maybe!- it is still in the break-in phase. But I'm out of options and it's driving season, and since I found no serious damage inside, I'm gonna drive it! If there is a serious problem, I guess it will eventually show up.

Are the pistons solid skirt or split skirt? This could be the problem. It has been my experience that split skirt pistons will expand more.

Tom Wesenberg · 06-03-2015, 06:45 AM

I don't recall, did you post pictures of the piston skirts?
Show both sides, the thrust side and the opposite side of the skirt.

d.j. moordigian · 06-03-2015, 03:03 PM

Ya...I'd like to see photos of the skirts..

Something is wrong in #4 hole..also some others..
Either it was put together dirty or the pistons are sticking(could be the rings are welding
too the walls), use a magnifying glass on the rings. The holes look out-of-round.
Find someone to truly measure the holes(top and bottom in 2 directions) and the pistons.

Look at the photos from the original post..

700rpm · 06-03-2015, 08:32 PM

Pistons are not split skirt, and there's no indication of damage to the cylinder walls beyond minor scratching, too fine to feel with a fingernail. Engine was sleeved back to standard and honed for final cylinder/piston fit by one of the best engine shops in Portland. Car runs rich, not lean (in spite of new Renner's jets).

old car guy · 06-03-2015, 08:38 PM

This might be a stupid question any chance that the sleeves are moving or expanding with the engine gets to operating temperature. Something has to be binding somewhere .

heneste · 06-03-2015, 10:17 PM

Any chance the oil pump may not be working up to full flow specs?

BILL WILLIAMSON · 06-03-2015, 10:21 PM

Quote:

Originally Posted by d.j. moordigian

Ya...I'd like to see photos of the skirts..

Something is wrong in #4 hole..also some others..
Either it was put together dirty or the pistons are sticking(could be the rings are welding
too the walls), use a magnifying glass on the rings. The holes look out-of-round.
Find someone to truly measure the holes(top and bottom in 2 directions) and the pistons.

Look at the photos from the original post..

700,
PLEASE listen & follow up with d. j, he is an EXPERT in this field. TRUST me, I've known him for about 38 FINE years!
Bro Bill W.

d.j. moordigian · 06-05-2015, 09:38 AM

Look at the bottom side of the rings,.....are they still dark or are they shinny?
Make sure the second ring is installed correctly, it's an oil control ring!

What does the "tops" of the rod bearings look like..photo?

Ya...it does have a lot of carbon and it's also rich..

katy · 06-05-2015, 11:20 AM

Quote:

checked my ring gap on the top two rings on all four cylinders

What about the end gap on the other rings?

Kahuna · 06-05-2015, 12:03 PM

Pull the pistons. Any scuffing will be noticed on them, and maybe not on the bore surface.

700rpm · 06-05-2015, 06:22 PM

Oil rings were gapped at .010. I pulled the pistons. No scuffing apparent.

colin1928 · 06-06-2015, 01:54 AM

I personally would keep inspecting the rest of the engine somewhere there is something with to little clearance if not piston and rings must be deeper in the engine

40 Deluxe · 06-06-2015, 11:34 AM

Maybe a defective sleeve is moving round at operating temperature and pinching a piston (or several) just enough to seize the warmed-up engine before the oil film is lost-thus no scoring. Stranger things have happened! If you just keep running it, as it breaks in, it may keep running long enough to wipe off the oil film and then score the pistons and walls.

1931 flamingo · 06-06-2015, 02:35 PM

Have you checked brg clearances??
Evidently you've got the pistons out, how hard is it to turn over with the pistons out??
With one in? with two in, etc??
Paul in CT

Wilbur · 06-06-2015, 02:52 PM

Be sure to look at the piston wrist pins. One of my Model T engines locked up due to the wrist pin seizing within the piston. This was a newly rebuilt motor with about 1500 miles on it. We pulled the engine apart and saw nothing wrong until it was noticed that one of the rods was "stiff". Had to cut the piston apart to salvage the rod. It's odd, but given the quality of our "new" parts nowadays, you have to look deep.

06-02-2015, 10:34 PM	#1
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,906	Update on ring clearances I've been struggling with what I perceived as an over-tight engine since the rebuild last spring. Here is the earlier thread on it: http://fordbarn.com/forum/showthread.php?t=154688 Most theories came down to too tight of a clearance on the rings. I finally pulled the pistons and checked my ring gap on the top two rings on all four cylinders, and they were all .020 ±, well within mfgr's specs (Hastings, from Snyder's). Piston clearance on all four was .004+, which also seems to be the consensus here and elsewhere on proper piston clearance. Tomorrow or the next day I’ll reassemble and drive it. I don’t know what else can be causing it to seize up when warmed up, except maybe -maybe!- it is still in the break-in phase. But I'm out of options and it's driving season, and since I found no serious damage inside, I'm gonna drive it! If there is a serious problem, I guess it will eventually show up. __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

06-02-2015, 10:40 PM	#2
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Update on ring clearances Are the coolant chambers totally clean, especially the rear two on the drivers side? That's where I find most of the rust and junk that accumulates.

06-03-2015, 02:25 AM	#5
pooch Senior Member Join Date: Sep 2010 Location: South Coast NSW Australia Posts: 2,596	Re: Update on ring clearances How is your gas flow? Even if you are checking the air/gas ratio idling, it may be starving a little on running at high speed and causing the innards to overheat and expand. I have always been told to make sure of no lean-ness on running in , and err on the side of richness . Could you fit an exhaust temp probe and then be able to check for overheating while driving ?

06-03-2015, 06:45 AM	#7
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Update on ring clearances I don't recall, did you post pictures of the piston skirts? Show both sides, the thrust side and the opposite side of the skirt.

06-03-2015, 03:03 PM	#8
d.j. moordigian Senior Member Join Date: May 2010 Location: Fresno, Ca. Posts: 3,636	Re: Update on ring clearances Ya...I'd like to see photos of the skirts.. Something is wrong in #4 hole..also some others.. Either it was put together dirty or the pistons are sticking(could be the rings are welding too the walls), use a magnifying glass on the rings. The holes look out-of-round. Find someone to truly measure the holes(top and bottom in 2 directions) and the pistons. Look at the photos from the original post..

06-03-2015, 12:13 AM	#4
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Update on ring clearances I agree, since the ring and piston clearances are fine, I see no reason for it to get tight and stop. If you have a temp gun, the next time it gets tight, I'd immediately take the temp of each spark plug base, and each cylinder just below the water jacket.

06-03-2015, 08:32 PM	#9
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,906	Re: Update on ring clearances Pistons are not split skirt, and there's no indication of damage to the cylinder walls beyond minor scratching, too fine to feel with a fingernail. Engine was sleeved back to standard and honed for final cylinder/piston fit by one of the best engine shops in Portland. Car runs rich, not lean (in spite of new Renner's jets). __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

06-03-2015, 08:38 PM	#10
old car guy Senior Member Join Date: May 2010 Location: tampa fl Posts: 194	Re: Update on ring clearances This might be a stupid question any chance that the sleeves are moving or expanding with the engine gets to operating temperature. Something has to be binding somewhere . __________________ old car guy

06-03-2015, 10:17 PM	#11
heneste Senior Member Join Date: Nov 2010 Location: Ottawa,Ontario, Canada Posts: 271	Re: Update on ring clearances Any chance the oil pump may not be working up to full flow specs?

06-05-2015, 09:38 AM	#13
d.j. moordigian Senior Member Join Date: May 2010 Location: Fresno, Ca. Posts: 3,636	Re: Update on ring clearances Look at the bottom side of the rings,.....are they still dark or are they shinny? Make sure the second ring is installed correctly, it's an oil control ring! What does the "tops" of the rod bearings look like..photo? Ya...it does have a lot of carbon and it's also rich..

06-05-2015, 12:03 PM	#15
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: Update on ring clearances Pull the pistons. Any scuffing will be noticed on them, and maybe not on the bore surface.

06-05-2015, 06:22 PM	#16
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,906	Re: Update on ring clearances Oil rings were gapped at .010. I pulled the pistons. No scuffing apparent. __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

06-06-2015, 01:54 AM	#17
colin1928 Senior Member Join Date: Mar 2013 Location: Australa Melbourne Posts: 878	Re: Update on ring clearances I personally would keep inspecting the rest of the engine somewhere there is something with to little clearance if not piston and rings must be deeper in the engine

06-06-2015, 11:34 AM	#18
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,779	Re: Update on ring clearances Maybe a defective sleeve is moving round at operating temperature and pinching a piston (or several) just enough to seize the warmed-up engine before the oil film is lost-thus no scoring. Stranger things have happened! If you just keep running it, as it breaks in, it may keep running long enough to wipe off the oil film and then score the pistons and walls.

06-06-2015, 02:35 PM	#19
1931 flamingo Senior Member Join Date: May 2010 Location: new britain,ct 06052 Posts: 9,390	Re: Update on ring clearances Have you checked brg clearances?? Evidently you've got the pistons out, how hard is it to turn over with the pistons out?? With one in? with two in, etc?? Paul in CT

06-06-2015, 02:52 PM	#20
Wilbur Senior Member Join Date: Nov 2012 Location: Mays Landing, NJ Posts: 113	Re: Update on ring clearances Be sure to look at the piston wrist pins. One of my Model T engines locked up due to the wrist pin seizing within the piston. This was a newly rebuilt motor with about 1500 miles on it. We pulled the engine apart and saw nothing wrong until it was noticed that one of the rods was "stiff". Had to cut the piston apart to salvage the rod. It's odd, but given the quality of our "new" parts nowadays, you have to look deep.