Ford 861 Blows Head Gasket

Anyone know or hear of history of Ford 861 blowing head gasket between 2 and 3 Cylinder? Has happened to mine 3 times and the third time is following a milling of head and confirmation block is within spec of clearance. So, I have talked to one mechanic that works on old Fords and he said this was a design flaw by Ford and there is really no fix other than retarding timing and using higher octane gasoline. I was thinking using a metal head gasket might be a temporary fix. Anyone know where metal head gasket for an 861 with 1/2" head bolts and 172 CI exist? Thanks very much.
 
I have never heard of such and I run an 841 which is the same series as the 861 is. I have blown one head gasket on it in all the years we have had it. One big thing is that you NEED to do is after you get the new head gasket on you run it till warm then shut it down let it cool for a little bit then re-torque the head bolts or you will in fact blow the head gasket again
 

Yes, I have heard of it, but this was on a Ford that had been "tweaked" a bit. They had milled quite a bit off of the head to increase the compression. It really woke up that Ford, but they did have to replace the head gasket occasionally.
 
Thanks Tractor Guru. You are absolutely correct on the torqueing process and yes for sure that is what I do (even though my tractor repair manual from Ford does not discuss the retorquing of the head bolts).
 
What kind of torque wrench you using? Might want to look into having yours calibrated.
My personal dislike is a clicker. Prefer a bending beam or electronic.
 
Having replaced mine once (4 cylinder 4000, same engine I believe) I warmed it up in the shop before I put too much tin back on and then re-torqued. I fully meant to re-torque them again (re-re-torque?) at the end of the season, and think I probably did (I'll have to check).

If not, does it make any sense to periodically re-torque or is it best left alone after the first re-torquing?

Bob
 
Thanks, Earnie. The torque wrench I use, and I am not a mechanic, is a manual one with an advancing arrow that points to the degree of torque when right amount of force applied to the arm. Not sure what you call it but that is best description I can give and not sure I can be calibrated.
 
Correction on spelling Ernie (sorry I spelled it Earnie) and meant to say at end of my response "don't think "it" can be calibrated not "I can be calibrated".....
 
(quoted from post at 08:09:58 04/24/17) Anyone know or hear of history of Ford 861 blowing head gasket between 2 and 3 Cylinder? Has happened to mine 3 times and the third time is following a milling of head and confirmation block is within spec of clearance. So, I have talked to one mechanic that works on old Fords and he said this was a design flaw by Ford and there is really no fix other than retarding timing and using higher octane gasoline. I was thinking using a metal head gasket might be a temporary fix. Anyone know where metal head gasket for an 861 with 1/2" head bolts and 172 CI exist? Thanks very much.


Most any engine will blow a head gasket eventually but it's unusual on that engine.If the head or deck hasn't been milled too much,a quality gasket used and proper torque applied it won't happen regularly.As to retarding the ignition timing and useing hitest-I'm 2 * ahead of spec. and have been running 87 octane for 20 years.There's not a design flaw either.
 
Thanks, Bob in SD for your comment. I am not a mechanic so just a comment to your question but I have not heard anyone say retorque after the initial retorque. I have always heard that when replacing the head, start tractor and let it run until warm (one person said let it run minimum 30 min) then let it cool and retorque. As I have mentioned a few minutes go on this thread, my Ford Tractor Repair Manual specifically for Ford 800 series does not mention retorquing at all but surely it should be done at least once.
 
Years ago when I worked for a dealer, there was an Oliver 770 and an 800 series Ford that would blow a head
gasket about once a year. I was told to use Permatex Hylomar. After about ten years, I lost track of the
Ford but, until then, it didn't blow a gasket and the Oliver is still running with the same gasket.
 
You'll want to stay with a good quality, name brand, composition head gasket. If the "metal" gasket you are looking for is a sandwich type, steel, stainless, or copper on the outside with a compressible core in between, that is a good combination. If you are looking for a single layer, embossed steel gasket, no that likely won't work for your application.

Most head gasket failures are the result of poor preparation. The surfaces must be absolutely free of old gasket sealer, carbon, rust, clean down to shinny metal. Also be sure all the passages between the head and block are clear of rust, scale, and old sealer. The threaded holes in the block need to be chased with a tap. Go back with factory new head bolts. If the bolts have flanged heads, built in washers below the hex, all the better. If not, use grade 8 hardened washers to prevent the heads from biting into the head as they are torqued. Bolts in blind holes need oil on the threads, bolts into the water jacket need non hardening sealer.

Do retorque the bolts! I do it with the engine hot. One trick to getting a good retorque is to very slightly back the bolt off, not much, just enough to feel it turn but not relieve the pressure, then take to the recommended torque.
 
Once you re-torque them the 2nd time there should be no reason to do it again or your likely to have problems
 
You have a bending beam torque wrench. The one I have has a set screw holding the pointer and the pointer is tapered so it will move the point as it is turned. All in all they seldom go out of calibration. Start in the middle of the head and work your way out; go up to first torque in 2 or 3 stages. Set valve clearances a little loose, start engine and get it to operating temperature and retorque and set final valve clearance. When you torque sneak up on final slowly; you will feel the fastener creep to the end point. As others have mentioned chase the stud holes with a tap and wire brush the bolt threads. Had a 172 blow a head gasket between 2+3 because it was running on 2 cylinders (every other one in the firing order). I surmise the uneven heat took out the gasket. I would make sure the ignition timing was right on; retarded timing will push BTU's out the exhaust and water jacket. Ditto for running carb lean. Check the head and block with a framing square for flatness. Check for sedimentation or casting sand in the block with a probe.
 
(quoted from post at 19:32:08 04/24/17) You'll want to stay with a good quality, name brand, composition head gasket. If the "metal" gasket you are looking for is a sandwich type, steel, stainless, or copper on the outside with a compressible core in between, that is a good combination. If you are looking for a single layer, embossed steel gasket, no that likely won't work for your application.

Most head gasket failures are the result of poor preparation. The surfaces must be absolutely free of old gasket sealer, carbon, rust, clean down to shinny metal. Also be sure all the passages between the head and block are clear of rust, scale, and old sealer. The threaded holes in the block need to be chased with a tap. Go back with factory new head bolts. If the bolts have flanged heads, built in washers below the hex, all the better. If not, use grade 8 hardened washers to prevent the heads from biting into the head as they are torqued. Bolts in blind holes need oil on the threads, bolts into the water jacket need non hardening sealer.

Do retorque the bolts! I do it with the engine hot. One trick to getting a good retorque is to very slightly back the bolt off, not much, just enough to feel it turn but not relieve the pressure, then take to the recommended torque.

Thanks Steve for the tips....all very informative!
 

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