400 blown head gasket - need help identifying cause

I have a blown head gasket on a 400 – S/N 154354 and I need help finding the cause. Here’s the history:

4 years ago I rebuilt this motor with an engine overhaul kit from YT – New sleeves, pistons, rods, bearings, seals, gaskets, etc. The valves didn’t look that great so I had the head rebuilt and checked for cracks at the local machine shop. They found a small crack around one of the exhaust valve guides, repaired it, installed new valves and seats and machined the head flat. This was my first crack at a tractor engine rebuild – I have rebuilt a couple auto engines. It has maybe 100 hours on the rebuild. I use it for moving hay, plowing snow in the winter and road repair in the summer so it doesn’t get a lot of use and sits idle for months at a time.

This summer it started cranking out white smoke and I have just now had a chance to work on it. A compression test showed all cylinders between 100-115 psi, but by the time I got to checking the last cylinder #4 was spraying coolant out the spark plug hole. Since the compression was reasonable, I figured it had to be a cracked head. When I tore it apart last night I found that the head gasket was shot around all of the water ports – see photos. The gasket is a TISCO. I used Permatex Copper Spray-A-Gasket Hi-Temp Adhesive Sealant on it. Coolant was 50/50 with distilled water. Head nuts were evenly torqued to spec.

So I’m stumped, what did I do wrong? Are Tisco gaskets junk? Any ideas and suggestions for the reassembly are greatly appreciated.

Also what is the best way to make sure all the coolant is cleaned out of the engine? Is changing the oil a couple times after it is back together sufficient or is there some type of additive that will help clean the water out?

Thanks.

James

Every failure I see on your picture looks to be
right where the head gasket crosses over from
block to the flange of the sleeve. This would
indicate that the sleeve flange is protruding too
far over the top of the block. Book says something
like .004 max but I personally always felt that
was too much. I have seen an engine with new
sleeves this summer that were .008 above block and
it leaked immediately. A friend of mine was
working on it and He had a couple of choices.
Machine block with sleeves installed for flush
sleeve, cut counter bore for sleeve or machine the
flange of the sleeve down. He did not want to pull
the sleeves out so he had the block machined down.
This method IH always uses of the head gasket
crossing off and back onto the sleeve flange is in
my book not one of their better ideas. Always
questioned it but normally works ok if protrusion
is slight.

that head gskt. sure dont look right. if the fire rings in the gskt. were round to match the cyls. that would not happen. it kinda dont even make sense to have some sleeve protrution if that is the correct gskt?

Also check the running timing. Could be from detonation.

Do you happen to remember what you had the head torqued to? Each of your failures is right where the gasket is the thinnest between the cylinder sealing ring on the gasket, and the water port. All of those failures show heat erosion.

I agree with checking the sleeve height above the deck, but this also looks like a head not propery torqued down.

Thanks for the replies.

I measured the sleeve "stick-out". The most I get is .005 - so maybe that is the issue. Sure would be difficult for me to get the whole block into a shop to machine the top. Anyone have experience with how much I can get away with?

This does seem like a weird gasket design. It would make way more sense if the cylinder holes were round and matched the sleeves. Is there anyway I can verify that I had the correct gasket?

I've checked the timing periodically and it has been OK. I've never noticed it knocking.

The design of the head gasket fits the shape of he combustion chamber in the head and is not round. You find this on most IH gasoline engines. Like I said, never thought it was a good idea.

Head bolts were torqued to 110 ft-lb per the manual. The manual also says the sleeves may project a max of .006 but should not be below the surface.

The .006 is too much for a good seal. The one I was
talking about was a 300 gas and it had .008 and it
leaked immediately. I like it around .002 but don't
always have a choice. I always use Permatex Indian
Head sealer around those questionable spots. I like
it better than copper coat or aluminum paint.

Thanks all for your knowledge. Here's an update.

I borrowed a depth mic and rechecked the sleeve stick-out. Found that the max is .003 - most measurements were in the .001-2 range. Using the end of my old calipers wasn't doing a very good job of measuring. So I should be OK there.

Someone here locally asked if I had retorqued the head. I had not done that - manual didn't say to. Should I have to retorque them? If so, how long should I run it before a retorque?

On the detonation possibility... I pulled apart the distributor and found that the pivots on the advance weights had a lot of slop and the springs looked a bit stretched. Would this be enough to give me detonation issues?

I checked with the IH dealer and they can't get new springs anymore. Steel Wheel Ranch has some used springs, but I have no idea if they would be any better than what I have. Anyone know of a source for NOS springs or a way to verify if mine are OK?

Thanks.

Check with Joe's Farmall, he is Gordon Rice's son from Rice Equipment, and specializes in letter series parts.

on the re-tourque, fairly simple. Install new head gasket and torque to specs. run up to operating temp for a short while, then shut her down and check torque again on all head bolts/nuts.

I agree with the head gasket not being correct for your application. It should match the profile block surface much more closely. Maybe this type is all that is available now.
Any type of sealer wouldn't have prevented this, I also agree possibly not retorqueing the head was possibly the cause.
Liner protrusion is increased or decreased by machining the block surface directly below the liner lip. Determine what IH recommends for liner protrusion above block deck, measure (mike) your new ( or used) liners, then measure top deck of block to bottom surface of liner bore at four spots on each cylinder, this average will give you whether to machine the top deck surface of the block and recut the liner depths to match, or if they are still within limits, and can be used as is. At your measurement of .003 & less I would say this would be acceptable as is.

I think I may have found the cause for my blown gasket. When I cleaned up the block surface, I found that there is a decent size gap between the sleeve and the block. I now recall that the machine shop that rebuilt the head for me 4 years ago also lent me plates to use for pressing the sleeves in. They recommended filing a slight chamfer on the block so that the sleeves would start easier. This is probably fine to do on just about any other motor, but not this one. As Pete noted, the gasket matches the underside of the head and not the sleeves, the cylinder gasses can get into this "v" caused by the chamfer and then work their way under the gasket until they break out into the cooling ports. So looks like I really shot myself in the foot on this one.

I have no way of getting the block into a machine shop to machine it down until the v groove is gone and even if I did it would probably require 50-100 thou to completely get it. I have no idea what this would do to the compression ratio.

Now my question is: is there anything I can use to fill that v groove? JB weld? Devcon? It is .010-.020 wide and .10-.05 deep.

Eventually I suppose I will learn to completely think through what someone recommends.