The Ford Barn

Bud · 03-05-2017, 08:21 PM

I am working on putting my B engine back together. The block had cracks from the valve seat area to the water jacket. I had these stitched. The engine shop lightly honed the bores to clean them up. Everything has been cleaned up. I am measuring the crank and connection journals, plus have plastigaged all the bearings. I don't have the measurements in front of me, but basically the mains are .0020" and the connections are .0010" diametral clearance. Once I had the crank installed with no pistons it was easy to turn but I would not say it would spin by hand. This engine had about a 1000 miles on it after a rebuild before the cracks became apparent. I have installed a bronze timing gear, a Stipe cam, set all the valves, and cleaned up and installed the pistons.
I did have to install a new connection on #3 because I messed up the thrust surface of the connection babbit--my installation mistake. I re-plastigaged that connection and it had .0010" clearance. Since I have installed that piston assembly and #4 piston assembly, the crank has been very difficult to turn. I plan to go in and investigate #3, but I thought I would ask what I should expect regarding turning effort with all four pistons installed plus cam with valves and springs? The cylinder head is not installed. I think I have in excess of 150 ft-lbs of breakaway torque. That is with everything very well oiled. I would like some idea of what torque I should expect at the stage where it is just the crank, just the crank and cam, and what torque I should pick up by adding each piston assembly. Thanks in advance for any information you are willing to share.

PC/SR · 03-05-2017, 09:02 PM

IMHO, your connecting rod clearance is to tight. Should be .015 minimum. I think torque should be 35-50 max. You can chase this down by loosening the connecting rod caps one at a time and see if one (#3?) gives immediate relief.

MikeK · 03-05-2017, 09:11 PM

Rebabbited or any reused connecting rods need to be carefully checked for absolute pin parallelism. A bend or twist of just a few thousanths may not show up when you plastigauge the big end for clearance, but will make the assembly bind up when the crank rotates.

If you cannot rotate the entire short block assembly with one hand using the hand crank something is wrong.

An extremely tight renewed A engine with new rings on un-run fresh honed cylinders should crank over with less than 50 ft-lbs once it starts moving.

Bud · 03-05-2017, 09:34 PM

Thank you all for your comments, I will investigate to see what the problem is. It may take a few days.
Thanks again.

Mark in MT · 03-06-2017, 10:47 AM

Check to see that the cap is correctly oriented on the rod, if it is reversed it will bind up when torqued. ( Don't ask me how I know.) This is due to slight misalignment of rod when boring so that it is not perfectly symmetric. A .001 offset will be enough to make it tight. Loosen the rod caps one at a time and try to turn the engine. If it turns properly after a certain rod is loosened, that rod is the culprit. Try reversing the cap on the rod and retest. Of course, make sure that the dipper on the cap is facing the camshaft side when you are all done.

Mark

Fullraceflathead · 03-06-2017, 11:38 AM

Sponsored Links (Register now to hide all advertisements)

.0015 not .015, I know this was a typo.

Art Newland · 03-06-2017, 01:18 PM

I just warmed over an engine and was surprised how hard it was to spin-over. While all the pistons are half hay down the bores, it takes a lot of force. Wasn't re-bored but piston clearances were in the .004 range with .004-5 taper at the top. New rings and honing. All bearings with .0015 clearance. Started up on a test stand and she cranked over slow!
https://www.youtube.com/watch?v=4J6xPvcaA68&t=114s

Jim Brierley · 03-06-2017, 02:43 PM

Check the side clearance on the new rod, check them all while you are at it. Minimum clearance should be .003", more is fine. I set my racing engine side clearance at about .010". I also agree with PC/SR and Mike K.

Bud · 03-06-2017, 11:32 PM

I loosened up connecting rod cap #3 and the entire assembly was easy to turn over. As well as I can determine with my poor measurement tools is that I am size-to-size with the crank. I cannot say how I got .001" clearance on the plastigage before, but I am going back over this assy now. I plan to borrow a bore gauge to bring this rod to the proper size. I have a brake cylinder hone that I can use and it has cleaned up the ID of the babbit quite well. I have probably taken out only a couple .0001" so far. Thank you all for your comments--much appreciated.

PC/SR · 03-07-2017, 12:15 AM

Be really really careful with the brake cylinder hone. You can take off too much in an instant, and get an uneven bore. I would strongly recommend shims if you want to increase the clearance. You can sand the shims on a flat plate or glass to get fine adjustments. Or just mix and match shims until you get the clearance you need.

Tom Wesenberg · 03-07-2017, 12:29 AM

I too would increase clearance with shims.
What would happen to the crank if a few grains from the hone get imbedded in the babbit?

ursus · 03-07-2017, 02:40 PM

Ditto the comment by PC/SR. I once heard an older machinist chew out a young apprentice who had announced his intent to line hone the babbitted mains on an old Dodge engine. After a few expletives, he very emphatically stated: "You cannot hone babbitt, it melts!"

My method is to use some Timesaver lapping compound, if you can get it.

George Miller · 03-07-2017, 03:34 PM

Brake hone is not a good idea. Take it from a old machinist.

Bud · 03-07-2017, 10:14 PM

I see your point regarding the hone. At this point I only cleaned up the surface finish in the connection. I doubt I have removed more than .0002". I will cease using the hone. Unfortunately I am still basically at size to size with the crank. I can make a couple of .0015 or .0020" shims, but that only takes care of the dimension in the vertical plane. The sides of the connection are still size-to-size with the crank. I do have bearing scrapers and could hand scrape the sides out, but I've never done that. I have Prussian blue and could work on it. I am reluctant to send this connection back to where it was originally bored. To set it up and accurately take out .0015" and actually hit the dimension seems like a long shot to me. I don't want to make this someone else's problem either (I know some machinists but they should not have to be responsible for someone else's work).
Any other suggestions would be appreciated before I decide what to do. Thanks.

George Miller · 03-08-2017, 07:22 AM

Why not try putting a .001 shim on both sides. That would give you .001 more clearance. It will also give you a little more on the sides. If the bearing was size to size it would lock up the crank and it would not turn at all.

PC/SR · 03-08-2017, 11:57 AM

Like Ursus, I like Timesaver. It will give you a round bore. But calling it Timesaver is a misnomer. It takes time because you are doing a lot of disassembling for measurements until you get a feel for it. Google it and sources come up.
Or start out with .001 shim per George above. Lot quicker and easier.

03-05-2017, 08:21 PM	#1
Bud Senior Member Join Date: May 2010 Location: Ohio Posts: 819	Turning Torque of B Engine I am working on putting my B engine back together. The block had cracks from the valve seat area to the water jacket. I had these stitched. The engine shop lightly honed the bores to clean them up. Everything has been cleaned up. I am measuring the crank and connection journals, plus have plastigaged all the bearings. I don't have the measurements in front of me, but basically the mains are .0020" and the connections are .0010" diametral clearance. Once I had the crank installed with no pistons it was easy to turn but I would not say it would spin by hand. This engine had about a 1000 miles on it after a rebuild before the cracks became apparent. I have installed a bronze timing gear, a Stipe cam, set all the valves, and cleaned up and installed the pistons. I did have to install a new connection on #3 because I messed up the thrust surface of the connection babbit--my installation mistake. I re-plastigaged that connection and it had .0010" clearance. Since I have installed that piston assembly and #4 piston assembly, the crank has been very difficult to turn. I plan to go in and investigate #3, but I thought I would ask what I should expect regarding turning effort with all four pistons installed plus cam with valves and springs? The cylinder head is not installed. I think I have in excess of 150 ft-lbs of breakaway torque. That is with everything very well oiled. I would like some idea of what torque I should expect at the stage where it is just the crank, just the crank and cam, and what torque I should pick up by adding each piston assembly. Thanks in advance for any information you are willing to share.

03-05-2017, 09:02 PM	#2
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Turning Torque of B Engine IMHO, your connecting rod clearance is to tight. Should be .015 minimum. I think torque should be 35-50 max. You can chase this down by loosening the connecting rod caps one at a time and see if one (#3?) gives immediate relief.

03-06-2017, 10:47 AM	#5
Mark in MT Senior Member Join Date: May 2010 Location: Western MT Posts: 218	Re: Turning Torque of B Engine Check to see that the cap is correctly oriented on the rod, if it is reversed it will bind up when torqued. ( Don't ask me how I know.) This is due to slight misalignment of rod when boring so that it is not perfectly symmetric. A .001 offset will be enough to make it tight. Loosen the rod caps one at a time and try to turn the engine. If it turns properly after a certain rod is loosened, that rod is the culprit. Try reversing the cap on the rod and retest. Of course, make sure that the dipper on the cap is facing the camshaft side when you are all done. Mark __________________ Mark in MT Always looking for another opportunity to be wrong.

03-06-2017, 11:38 AM	#6
Fullraceflathead Senior Member Join Date: May 2012 Location: Chillicothe, Missouri Posts: 1,176	Re: Turning Torque of B Engine Sponsored Links (Register now to hide all advertisements) .0015 not .015, I know this was a typo. __________________ "If I asked people what they wanted they would have said faster horses." -Henry Ford "Primitive technology is not a design flaw" 1928 Ford Model A Roadster Pickup 1930 Gordon Smith Air Compressor 1941 Willy's Pickup 1960 Thunderbird-For Sale 1964 Buick Riviera 2x4 425 1965 Pontiac GTO, 455 Super Duty 2004 Dodge Ram SRT-10, V-10 Viper 1977 Charger Jet Boat,460 Ford,Jacuzzi Jet Front Engine Nostalgia Dragster,Supercharged 296 "Fullrace Flathead" Ford Engine Build up on DVD ask

03-06-2017, 01:18 PM	#7
Art Newland Senior Member Join Date: Mar 2016 Location: Lynden, WA Posts: 1,564	Re: Turning Torque of B Engine I just warmed over an engine and was surprised how hard it was to spin-over. While all the pistons are half hay down the bores, it takes a lot of force. Wasn't re-bored but piston clearances were in the .004 range with .004-5 taper at the top. New rings and honing. All bearings with .0015 clearance. Started up on a test stand and she cranked over slow! https://www.youtube.com/watch?v=4J6xPvcaA68&t=114s

03-05-2017, 09:11 PM	#3
MikeK Senior Member Join Date: May 2010 Location: Windy City Posts: 2,919	Re: Turning Torque of B Engine Rebabbited or any reused connecting rods need to be carefully checked for absolute pin parallelism. A bend or twist of just a few thousanths may not show up when you plastigauge the big end for clearance, but will make the assembly bind up when the crank rotates. If you cannot rotate the entire short block assembly with one hand using the hand crank something is wrong. An extremely tight renewed A engine with new rings on un-run fresh honed cylinders should crank over with less than 50 ft-lbs once it starts moving.

03-05-2017, 09:34 PM	#4
Bud Senior Member Join Date: May 2010 Location: Ohio Posts: 819	Re: Turning Torque of B Engine Thank you all for your comments, I will investigate to see what the problem is. It may take a few days. Thanks again.

03-06-2017, 02:43 PM	#8
Jim Brierley Senior Member Join Date: Jun 2010 Location: Temecula, CA Posts: 4,088	Re: Turning Torque of B Engine Check the side clearance on the new rod, check them all while you are at it. Minimum clearance should be .003", more is fine. I set my racing engine side clearance at about .010". I also agree with PC/SR and Mike K.

03-06-2017, 11:32 PM	#9
Bud Senior Member Join Date: May 2010 Location: Ohio Posts: 819	Re: Turning Torque of B Engine I loosened up connecting rod cap #3 and the entire assembly was easy to turn over. As well as I can determine with my poor measurement tools is that I am size-to-size with the crank. I cannot say how I got .001" clearance on the plastigage before, but I am going back over this assy now. I plan to borrow a bore gauge to bring this rod to the proper size. I have a brake cylinder hone that I can use and it has cleaned up the ID of the babbit quite well. I have probably taken out only a couple .0001" so far. Thank you all for your comments--much appreciated.

03-07-2017, 12:15 AM	#10
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Turning Torque of B Engine Be really really careful with the brake cylinder hone. You can take off too much in an instant, and get an uneven bore. I would strongly recommend shims if you want to increase the clearance. You can sand the shims on a flat plate or glass to get fine adjustments. Or just mix and match shims until you get the clearance you need.

03-07-2017, 12:29 AM	#11
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: Turning Torque of B Engine I too would increase clearance with shims. What would happen to the crank if a few grains from the hone get imbedded in the babbit?

03-07-2017, 02:40 PM	#12
ursus Senior Member Join Date: May 2010 Location: Oregon Posts: 1,375	Re: Turning Torque of B Engine Ditto the comment by PC/SR. I once heard an older machinist chew out a young apprentice who had announced his intent to line hone the babbitted mains on an old Dodge engine. After a few expletives, he very emphatically stated: "You cannot hone babbitt, it melts!" My method is to use some Timesaver lapping compound, if you can get it.

03-07-2017, 03:34 PM	#13
George Miller Senior Member Join Date: May 2010 Location: NC Posts: 2,975	Re: Turning Torque of B Engine Brake hone is not a good idea. Take it from a old machinist.

03-07-2017, 10:14 PM	#14
Bud Senior Member Join Date: May 2010 Location: Ohio Posts: 819	Re: Turning Torque of B Engine I see your point regarding the hone. At this point I only cleaned up the surface finish in the connection. I doubt I have removed more than .0002". I will cease using the hone. Unfortunately I am still basically at size to size with the crank. I can make a couple of .0015 or .0020" shims, but that only takes care of the dimension in the vertical plane. The sides of the connection are still size-to-size with the crank. I do have bearing scrapers and could hand scrape the sides out, but I've never done that. I have Prussian blue and could work on it. I am reluctant to send this connection back to where it was originally bored. To set it up and accurately take out .0015" and actually hit the dimension seems like a long shot to me. I don't want to make this someone else's problem either (I know some machinists but they should not have to be responsible for someone else's work). Any other suggestions would be appreciated before I decide what to do. Thanks.

03-08-2017, 07:22 AM	#15
George Miller Senior Member Join Date: May 2010 Location: NC Posts: 2,975	Re: Turning Torque of B Engine Why not try putting a .001 shim on both sides. That would give you .001 more clearance. It will also give you a little more on the sides. If the bearing was size to size it would lock up the crank and it would not turn at all.

03-08-2017, 11:57 AM	#16
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Turning Torque of B Engine Like Ursus, I like Timesaver. It will give you a round bore. But calling it Timesaver is a misnomer. It takes time because you are doing a lot of disassembling for measurements until you get a feel for it. Google it and sources come up. Or start out with .001 shim per George above. Lot quicker and easier.