Valve stem wiggles in the guide? Guide out of round. See pic please

reweb67

Well-known member
1967 Mustang with stock 200 six. Car oil fouls 2 plugs in about 5 miles of driving. Cylinders look wet if I look inside the plug hole with a flashlight. Others cylinders are dry. Have done full tune up and rebuilt carb. Compression is 180 to 190 all.

I used the rope trick and pulled the valve spring on one of the oil fouling cylinders. Guide looks out of round and valve stem wiggles a bit on the guide. Here is a picture. Time to pull the head? :banghead:
 

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Pull the head & have a qualified machine shop replace all the valve guides & install vitron valve guide seals. While you have the valves out back-cut the intake valves with a 30 degree cut after lapping in the valves. This may add 5-10 HP because of increased intake flow.
 
reweb67":2fyncmce said:
1967 Mustang with stock 200 six. Car oil fouls 2 plugs in about 5 miles of driving. Cylinders look wet if I look inside the plug hole with a flashlight. Others cylinders are dry. Have done full tune up and rebuilt carb. Compression is 180 to 190 all.

I used the rope trick and pulled the valve spring on one of the oil fouling cylinders. Guide looks out of round and valve stem wiggles a bit on the guide. Here is a picture. Time to pull the head? :banghead:

If you can wiggle the valve much then yes it's time to pull the head and have the guides replaced. Good luck :nod:
 
Thanks for the replies.

I spun the engine by hand and lowered the rope down so the the valve would drop a 1/2 inch. Wiggling is worse like that. Has a nice solid clunk clunk noise as the valve stem hits either side of the guide walls.

Sounds like I will have to pull the head. Here is my question. If the valve seal is in fair shape (still complete and relatively flexible) Is it possible for a ton of oil to drip down the guide? My rubber valve seals do look ok.

If I understand umbrella type valve seal right, they only ride tight down on the guide when a car is at speed right? I noticed when I pulled the valve cover that some were up off the guides and some were sitting over the guides.

Maybe oil is dripping through the guide at idle enough to foul out my plugs in the cylinders with bad guides? Is this likely?
 
If you can wiggle them like that, then yes that is a big source of your oil fouling problems. The umbrella seals only marginally help, and they don't stay down. That's why Bill recommended the vitron valve guide seals in your rebuild, they are attached much more positively to the head (that's why machining is necessary) and help control the oil better.
 
Hi, in the 60s and 70s the valve job was normal after 100,000 to 125,000 miles. You did the work or got another car, and sold the oil burner as a mechanics special. Your car already had a valve job because I see spring shims in the picture. If you love the car and the hobby get it done right. There are many machine shops that are happy to work on vintage engines, and the parts are easy to find. Good luck
 
yes, as part of a good machinist job that area would B machined so 'umbrellas' R never used again.
Just 1 of the 'moderization' operations done on head wrk. Plez learn ALL of them & specific 1s
needed for ur application/end use of the vehicle - so U can point them out to the machinist when
dropping off the head.
 
The valve stems can also have wear on them, keep in mind that when two parts rub together they both wear out. So this could end up being a multi-wear situation and the valve stems needs to be checked for wear and the valves may need to be replaced as well, so don't assume its just the guides.
 
Appreciate all the info.

The plan is to suck it up and pull the head. Not happy about it though. I only have 25 or 30,000 on the engine since it had a full rebuild. Guessing they only knurled the guides then so that is why I'm having to do this :devilish: .

I do want it fixed right. Will have the new guides milled so viton seals can be used and check the valves etc to be sure they are ok.

After I get the head off I will ask here what else you guys may suggest I have done while it is off. Thanks again! :beer:
 
"...what else ... may suggest..."
C above referenced Handbook'n Tech Archive -
(a Level III machining as seen in Tech Archive under 1 of the "Hopping Up")
 
I would not sink any money in that dog log unless I could not find a late model with larger log, valves and hardened seats to freshen up.
Unfortunately it would need to be milled to keep the compression up and a larger carb.
 
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