Ford 6.8L V10

[Nuggets]

I've been seeing alot of Ford V10s coming into the shop with bad main and/ or rod bearings. The 4.6 and 5.4 motors seem just about indestructable but this v10 is just not cutting it. Since the v10 is just like the v8 with 2 more cylinders I'm confused. I have two hypothysis: 1) The longer crankshaft is developing a harmonic frequency at certain rpms and it's damaging the bearings. 2) This engine is "under engineered" for its application and it is coming apart due to excessive wear/abuse. I see this engine in alot of F/E 350-550 trucks so it may just not be suitable for these heavier applications.

What are your thoughts? Any references dealing the cause or conditions of this probem would be greatly appreciated.

[Nuggets]

No takers? Love some info.

[bogginboy]

not sure but i can do a quite motor swap on them now

[MuddyPaws]

I see just the opposite. The v8's crapping out. I have one in my shop right now that I can't get the bearings off the crankshaft. Damn things are junk. Either they blow the head gasket or they take out the crank.

[Nuggets]

Originally Posted by MuddyPaws

I see just the opposite. The v8's crapping out. I have one in my shop right now that I can't get the bearings off the crankshaft. Damn things are junk. Either they blow the head gasket or they take out the crank.

That's interesting. I haven't seen alot of v8s give up the ghost. The only 4.6and 5.4 motors I've seen with issues are the ones that have not been maintained or have been overheated. I used to do alot of work on Bay County Sheriff's cars and the engines seem to hold up very well. These cars were cycled out after 100 to 120k miles on them and I think I've only seen an internal engine problem with one of them.

[MuddyPaws]

Wow, when I was working at the ford dealer we put head gaskets on them almost as much as we did the first gen 3.8's in the taurus'.

Now that I think about it...they were always trucks.

[Nuggets]

Originally Posted by MuddyPaws

Wow, when I was working at the ford dealer we put head gaskets on them almost as much as we did the first gen 3.8's in the taurus'.

Now that I think about it...they were always trucks.

I guess I've been lucky enough not to have to deal with head gasket issues with these motors. From what I understand, the machining process is critical for good head gasket sealing. My local machine shop said that nobody in the area has equipment that can resurface the cylinder heads to Ford's specs.

[chris1044]

Theory: This is going off what I've learned, and what i've heard......the V10 has a fucked up firing order (meaning it doesn't have the simple fire once every 45* rotation thing that the V8 has going for it). I could have sworn that this makes the v10 a rod/crank bearing pounding engine....but I can't remember where I read/heard it. I think that the firing time along with the firing order makes that motor combo very hard on lower end bearings.....I think that it's also a case of the engine being under engineered....

But, honestly I can say I haven't seen a whole ton of the V-10 motors


As far as the 4.6's and 5.4's go, the main problem I've seen is the timing chain issue...that and exhaust manifolds like to rott big time up here in the rust belt.....

[Nuggets]

Originally Posted by chris1044

Theory: This is going off what I've learned, and what i've heard......the V10 has a fucked up firing order (meaning it doesn't have the simple fire once every 45* rotation thing that the V8 has going for it). I could have sworn that this makes the v10 a rod/crank bearing pounding engine....but I can't remember where I read/heard it. I think that the firing time along with the firing order makes that motor combo very hard on lower end bearings.....I think that it's also a case of the engine being under engineered....

But, honestly I can say I haven't seen a whole ton of the V-10 motors


As far as the 4.6's and 5.4's go, the main problem I've seen is the timing chain issue...that and exhaust manifolds like to rott big time up here in the rust belt.....

It should be firing every 36 degrees if I remember right. When they run good they seem like a pretty smooth engine.

[chris1044]

I know, they do seem smooth, but for some reason I want to say I've heard that it's an issue....i'll try to find out more if I can over the course of the week.....as now I'm interested in it as well

[MuddyPaws]

Originally Posted by Nuggets

I guess I've been lucky enough not to have to deal with head gasket issues with these motors. From what I understand, the machining process is critical for good head gasket sealing. My local machine shop said that nobody in the area has equipment that can resurface the cylinder heads to Ford's specs.

:tonka: :tonka: :tonka:

Even Ford didn't have the equipment I guess. They sent a service message out about faulty sealing surfaces and some crap about a speck of dirt getting on there during the assembly process that causes the head gasket failures.:chiefwoohaw: I thought at the time that it should be able to tollerate a speck of dirt.

I'll upload a pic tonight of that bearing.

[MuddyPaws]

I think this is the second to the last bearing in the rear of a v8. The bearing is fused to the crank.