Vintage Mustang Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Hi Guys,

I have my 1968 289 intake and heads off...because there was smoke coming out of the tail pipes and coolant overflowing from radiator once thermostat opens. But it never overheats. Opened it up and one head gasket is backwards... one side of intake gasket looked alittle kinked....ports and heads are sooty...intake valve stems in port are more sooty and have some build up...My valve stem seals...Intake guides look original...maybe....but have positive type seas...is that normal? They dont look machined from what I can tell. The exhaust valves have umbrella seals and the exhaust guides look like they were "knurled"...outside diameter of guide is skinnier than intake and the inside of exhaust guide has threads. Does this smoke look like valve leak? Also...the smoke didnt look as bad when i used mobil 1 sythetic...coincidence or does mobil 1 burn clear? Could the overflow in radiator be from backwards head gasket?




Thanks


Ryan
 

·
Registered
Joined
·
35,839 Posts
I have my 1968 289 intake and heads off...because there was smoke coming out of the tail pipes and coolant overflowing from radiator once thermostat opens. But it never overheats. Opened it up and one head gasket is backwards...
Oh, nice. Who assembled the engine?

one side of intake gasket looked alittle kinked....ports and heads are sooty...
Normal.

intake valve stems in port are more sooty and have some build up...
Not normal.

My valve stem seals...Intake guides look original...maybe....but have positive type seas...is that normal?
No.

They dont look machined from what I can tell. The exhaust valves have umbrella seals and the exhaust guides look like they were "knurled"...outside diameter of guide is skinnier than intake and the inside of exhaust guide has threads.
Knurling is an old, cheap way to fix these. Cast-iron guides are the only correct repair.

Does this smoke look like valve leak?
Valves smoke mostly on deceleration, not so much at idle.

Also...the smoke didnt look as bad when i used mobil 1 sythetic...coincidence or does mobil 1 burn clear?
Oil does not burn clear.

Could the overflow in radiator be from backwards head gasket?
No doubt. The back end of the head and block on that side was running blazing hot, lucky it didn't just puke all the coolant as you drove.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #4
So I checked deck and heads for warping and cracks....nothing...everything looks good from what I can tell with a metal straight edge.

All cylinder had around 130-135 psi with flat top pistons with valve reliefs. Normal compression? So I dont "think" it's piston rings....

Also, before I dismantled top end I took the exhaust manifolds off and looked to see which cylinders were shooting out smoke while engine was idling. Well...Cylinders 1,4,6,7 were shooting the most consistant smoke at idle...even some flames from 1 and 6. The other cylinders shot out little to no smoke unless I revved the motor.

Cylinders 1,4,6,7 are provided air/fuel from the same carb/intake port and their exhaust valve faces and spark plugs were sooty.

Cylinders 2,3,5,8 had little to no smoke and exhaust valve faces and spark plugs were redish/greyish/tan.

Do different brand motor oils burn differently?
 
1 - 4 of 4 Posts
Top