Bad Valve Seal #6

[Timbuck]

Thanks OP. This is a very helpful thread.

“Mine is 2017 mustang“

I have a fresh , sleeved forged rods/piston coyote. ever since I put it back together I’ve been burning oil. Way more than your average coyote or fords factory allowances etc.
about 1L per 1000kms Or around 1 quart , per 600 Or so miles.
I’ve done 20,000kms or 12k miles on the new engine , now and everything with the engine tests out perfect , no blow buy etc , cross hatching is perfect in each cylinder and engine runs like a clock and pretty much oil consumption stays the same As it’s alway been.
The wierd thing is cilinder 5 , 6, 7 seem to be a little oily. cylinder 6 probably the worst.
1 2 3 4 are bone dry with zero oil. So maybe one of the 4 packets I brought from ford had wrong sizes in it When I put the heads and put it back together.
one thing to note in resent weeks it has blown a small puff of smoke but only on 2 occasions. On morning start up. I drive it every day so it’s not a common thing.

as far as I can tell , this seems like it is probably my issue ??? I’ll get the valve cover off and inspect valve stem area for any problems.

Then I guess order a tool and some seals And get them set to australia.

cheers

Tim

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[ice445]

Thanks OP. This is a very helpful thread.

“Mine is 2017 mustang“

I have a fresh , sleeved forged rods/piston coyote. ever since I put it back together I’ve been burning oil. Way more than your average coyote or fords factory allowances etc.
about 1L per 1000kms Or around 1 quart , per 600 Or so miles.
I’ve done 20,000kms or 12k miles on the new engine , now and everything with the engine tests out perfect , no blow buy etc , cross hatching is perfect in each cylinder and engine runs like a clock and pretty much oil consumption stays the same As it’s alway been.
The wierd thing is cilinder 5 , 6, 7 seem to be a little oily. cylinder 6 probably the worst.
1 2 3 4 are bone dry with zero oil. So maybe one of the 4 packets I brought from ford had wrong sizes in it When I put the heads and put it back together.
one thing to note in resent weeks it has blown a small puff of smoke but only on 2 occasions. On morning start up. I drive it every day so it’s not a common thing.

as far as I can tell , this seems like it is probably my issue ??? I’ll get the valve cover off and inspect valve stem area for any problems.

Then I guess order a tool and some seals And get them set to australia.

cheers

Tim

If its fresh after a build it could be bad machine work. A youtuber i watch Chris Sullivan battled this with a 4v motor. Turned out the boring wasn't done correctly and it was wider lower in the bore and out of spec but fine up top where you'd usually measure.

 

[Timbuck]

If its fresh after a build it could be bad machine work. A youtuber i watch Chris Sullivan battled this with a 4v motor. Turned out the boring wasn't done correctly and it was wider lower in the bore and out of spec but fine up top where you'd usually measure.

wow thats a very weird , and not sure how that’s possible with modern machines ??

for my engine its possible but not probable….

bottom end was sleeved and built by arguably one of the best and most pedantic engine builders in Australia ( a friend) , I also supplied aluminium block for a custom cnc machined torque plate
And as stated has no blowby or compression issues.

so kind of leaning towards the most logical explanation and valve stem seems like a good place to start.

 

[ice445]

wow thats a very weird , and not sure how that’s possible with modern machines ??

for my engine its possible but not probable….

bottom end was sleeved and built by arguably one of the best and most pedantic engine builders in Australia ( a friend) , I also supplied aluminium block for a custom cnc machined torque plate
And as stated has no blowby or compression issues.

so kind of leaning towards the most logical explanation and valve stem seems like a good place to start.

Were the heads reused from a previous engine or new? Im not saying it can't be valve seals, its not a bad place to start (check guides too), but the fact you have several problem cylinders stood out to me after seeing that other guy's issues is all (he had oil pooling like that as well). Im not saying your friend is a bad engine builder or something, just that weird stuff can happen and parts quality these days is problematic, so dont rule it out if you dont find any obviously bad seals.

 

[Timbuck]

only 10,000 miles on engine Before it broke a piston on start up. ( no idea why)

Yep. Original heads where use , I re-did all the valves with diamond paste made sure they Where all sealing well and bubble pressure tested. Guides and valves had no wear at all that could be seen So where used again. so new set of ford OEM valve stem seals and Away we go.

rev the engine it doesn’t smoke , hold at medium rpm it doesn’t smoke , even on the back off down a hill doesn’t smoke As you get back on it. Has zero blow by At all , I mean put a piece of paper over the oil cap hole. Also Nothing in PCV system

so I end up at the stem seals. I figured maybe I had a bad pack of 8 and I used some of them in those 3 cylinders.
or
something I did on assembly?? I don’t really know what you can do wrong ?? Lubed up and put in. The spring does the work holding them in.

I see that other thread where a guy had some wear out and leave rubber type residue on the valve stem itself ? Maybe some of mine have just failed.

anyway I’ll dig a little deeper tomorrow

 

[Timbuck]

Further deep dive.

using a bore scope I tried to see if I could visually pick up any issues with the stem seal , like abnormal wear or marks on the valve stem but all looked good. But very hard to see.

so brought a new cylinder tester and all cylinders tested perfect 180psi , cold , dry , with no fuel as I pulled injector fuse.

So unfortunately I must of got a bad batch or some wrong size OEM valve seals.

 

[8915GT]

OP, there is no way that's this wouldn't be covered under the power train warranty. I am shocked that you let them say it's not covered unless your mods voided the warranty.

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