Ford 8N Rebuild engine or not?

hammer_guy35 · Sep 15, 2013

I have a ford 8n that was running pretty good but just blew a head gasket. I took the head off and found the gasket problem. My question is, what should I look for now with the rest of the engine to decide if I should change the pistons and valves since I have most of the engine apart. The only obvious thing is see is some black carbon build up and pits in the top of some pistons. The valves have carbon buildup on them but they are not cracked or broken and seem to open and close when I crank the engine. The cylinder walls appear to be smooth and shiny with a little ridge built up at the top. Any advice would be greatly appreciated.

Bob · Sep 15, 2013

Based on the info you wrote, clean it up, and install new head gasket. My favorite is the laminated-type, sprayed with a coat of CopperKote on both sides, correctly torqued, then re-torqued when warm. Pits in the top of the pistons are insignificant.

Ultradog MN · Sep 16, 2013

You could go ahead and do $1500 of engine work on a tractor that's worth maybe $2000 when you are done. But I wouldn't.
I would do as Bob suggests and just put a $25 head gasket in it.

Dachshund · Sep 16, 2013

Depends - how long has it been since it was rebuilt? How good is "running pretty good"? If you have the engine torn down, go ahead and do a rebuild. Better now then having to do it all again in the near future. If you do most of the work (depending on what it needs) - it won't cost near $1500, and the tractor is worth more then that, just to have it running in tip-top shape.

ericlb · Sep 16, 2013

if it was running good just replace the head gasket and go, no need to do a rebuild untill it needs it. head gaskets are a common problem on the N series and not a big deal to replace

teddy52food · Sep 16, 2013

Make sure the head is straight. It may need planning before you put it back on. If it wasn't using a lot of oil , I would not overhaul it yet.

DaninKansas · Sep 16, 2013

I'd check out the cost of having the valves ground - usually that's a cheap process once you've done the labor. I wouldn't consider doing a complete overhaul on a good running tractor.

fixerupper · Sep 16, 2013

Have the head checked out. If it's cracked a new head doesn't cost all that much. As far as what it's worth, dollar figures don't depict what it's worth to you as a keeper. Jim

mkirsch · Sep 16, 2013

There's nothing you can "see" just by "looking" at this stage to indicate that the engine needs to be rebuilt or not.

The way you tell if an engine needs to be overhauled is when it is RUNNING. Hard to start even after ignition and carburetor tune-ups, blowing blue smoke, knocking... Those are things that indicate the need for arebuild. Carbon only indicates that you have an engine that has run at some point in its lifetime, not that anything is wrong.

Compression check. You're looking for consistent numbers. Don't know what an 8N needs but I'd expect anything above 90PSI, and again consistent, would be adequate.

If the tractor is doing what you want it to do, and isn't hard to start, blowing smoke, or knocking, fix the head gasket and leave the rest alone.

JRSutton · Sep 16, 2013

Kind of depends on how much you use the tractor.

If you rely on it daily, and it's been 10+ years since a rebuild, I think I'd just bite the bullet and do it.

But if it only gets light, occasional use, I'd just get the new head gasket in and call it a day. The thing will probably run fine for another 20 years.

If somewhere in between, I think I'd get the valves done - IF you know somebody's who's both good and cheap.

Then I'd put the head back on - and before going too much further - check the compression. If it's good enough, button everything up and be done with it.

all assuming of course there's nothing obvious like a 1/4" gouge from in a cylinder from something like a broken ring - etc.

hammer_guy35 · Sep 16, 2013

JR, Thanks for the reply, I will put the head back on and do a compression test and see what it shows. I use the tractor occasionally and plow my driveway with it in the winter. Its sounds like the overall advice is to change the head gasket and keep it running as is. It used to be a hard starting tractor until I put in an Electronic Ignition conversion and it was starting great. The new ignition was the best upgrade I have ever purchased just in case somebody else is thinking about doing it to their older machines.

Mike M · Sep 16, 2013

If it were mine or in my shop based on what you said I'd have the head checked for flatness and cracks,grind the valves since I have access to a valve grinder and put it back together with a NEW head gasket.

Ford 8N Rebuild engine or not?

hammer_guy35

New User

Bob

Well-known Member

Ultradog MN

Well-known Member

Dachshund

Member

ericlb

Well-known Member

teddy52food

Well-known Member

DaninKansas

Member

fixerupper

Well-known Member

mkirsch

Well-known Member

JRSutton

Well-known Member

hammer_guy35

New User

Mike M

Well-known Member

Similar threads