Valve Guides

[84CAB]

Another noobie question - What are the symptoms of a bad valve guide? I have been having a "miss" for the last several weeks, a couple of posts here regarding this and a trip to two mechanics. Now one of the shops is saying they have ruled out everything and it is a bad valve guide in cyl. 6... I say that is BS, the car has never smoked or used any oil in the 9 months/3,000 miles I have owned it. These things show signs of wear/failure that worsens over time, correct?? THANKS

[RoninLB]

what is the measurement on the valve guide test ?

so your spark plug is oil fouling ?

[84CAB]

what is the measurement on the valve guide test ?

didn't realize there was a test.. as far as I know they didn't do a test either. Yes there is oil on the plug.

[RoninLB]

Originally posted by 84CAB
.. as far as I know they didn't do a test either.

Yes there is oil on the plug.

if it was my car I'd start testing all valve guides till I found a worn one and either do a valve job or change all the valve stem seals. The seals can be done without pulling the heads. It's a kinda brainless time consuming job.

ps: meaning the seals only if the guides were ok.

[84CAB]

Ronin- would a problem with the valves not show up gradually over time? The car went from running perfect to running like #@$$ overnight. After changing out some ignition components.

[RoninLB]

I've only seen a gradual build up to an oil fouling plug. Maybe the stem seal crashed? I've never seen that happen so it's only a maybe from me.

btw how many miles? Has the engine ever been rebuilt?

[84CAB]

130,00 miles, don't know about the rebuild. when I bought the car I never heard of a PPI, Pelican or buying a documented car. I felt good about the car because it looked clean and had no oil leaks, and it didn't smoke at all. Until now the thing has ran as well as my wifes '04 Honda Accord.

[RoninLB]

hopefully it's only the stem seals and if you do the mindless job it'll cost you less than $50. Removing the rockers and doing the valve adjustment is the most complicated part of the job.

[JeremyD]

if it's fouling your plug - that's what causing your missing - but you know that. And valve guides - especially one one cylinder won't use much oil...

[johnsjmc]

If the shop has done a compression test on #6 , a low reading can explain a miss. If they haven,t then a leakdown or compression test is necessary.A valve needing adjustment,a bad injector or an ignition fault can also cause a miss If the exhaust valve guide is loose and is allowing the valve to wobble it could result in low compression without much oil loss. The intake valve guides and seals are usually the culprit (because they are operating under suction) if excess oil smoke is one of the symptoms. The best way to examine valve guides is to remove the spring and seal and measure the side to side movement in the guide. At 130000 you should expect to replace most of your guides and likely all the exhaust valves on teardown . If you are paying labour it gets expensive really quickly. It is possible to partially dismantle the engine and repair just one head if needed but the others are not far behind.

[jmohn]

Actually, you still don't know what's causing the "miss". with respect to "Ronin", I wouldn't start replacing seals just yet. I think you need to do a little investigating. When were the plugs, wires, cap, rotor last changed? Was any other work done on the car just prior to the "miss" developing? Could someone have "bumped" a wire unknowingly (check the injector wire connections). Verify plug wires are correctly routed and connected (even mechanics can make a mistake here). Pull the plug on number 6, if it's fouled, put in a new one (see if the miss goes away), now determine how long before the miss reappears. Is the plug fouled again? If it is, most likely a bad seal. If the miss reappears almost immediately, the problem is something other than a bad valve seal (a bad seal would take some time to re-foul the plug and cause a miss).

Good luck,

Jerry M
'78 SC

[84CAB]

Jerry - All this started when i replaced the cap and rotor, since then i have replaced the ignition wires(twice) changed the cap and rotor(again) and the mechanics have changed/checked everything imaginable.Now they say they have ruled out everything except the valves. I guess I am in denial as well as just plain stupid, because as I said earlier - before I changed the cap and rotor the car ran fine. It did not smoke before and still does not.

[JeremyD]

Elvis - do you have the catalytic converter installed? Also I would recommend you follow your car - driven by someone else - or have someone follow you with a video camera. Try downshifting from 4th to 3rd and look for puff os smoke - take up to high revs in 3rd and let the engine brake the car - that will suck oil into a bad exhaust guide and produce some smoke out the exhaust - usually difficult to see from the driver's seat.

[JeremyD]

Sure the distributor cap isn't cracked?

[84CAB]

Jeremy - yes the Cat is installed. I haven't followed my car yet. I will try that and see what happens.

Sure the distributor cap isn't cracked?

It has been changed twice. The first time I changed it was due to age. Thats when this whole thing began. I replaced it with another new one just to see if that might be the problem

[84CAB]

UNBELIEVABLE!! I picked the car up at lunch today. The shop owner said they never diagnosed the problem 100% and suggested they do a valve job in the near future do to the symptoms and the tech hearing a noise he couldn't explain... They charged me $349.00 for time spent troubleshooting and removing/cleaning the fuel injectors. Drove the car home and the miss was much better. Once home gave it the "once over" and found the rubber elbow at the AFM loose, and a hole in what looks to be a vacuum line going to a valve near the oil tank. Drove it more, MUCH BETTER. Returned home and put another rotor button on (the third time). PROBLEM FIXED!! THANKS for the help guys.

[RoninLB]

Originally posted by 84CAB

Yes there is oil on the plug.

so what happened to the oil fouled plug ?

[84CAB]

so what happened to the oil fouled plug ?

not sure, either the shop was wrong (ummm lied) or it was two faulty new rotor buttons. Probably a combination of both. Time to find a new shop either way.

[patkeefe]

either the shop was wrong (ummm lied)

Michael:
This sounds like the PM I sent you. One of the reasons I do everything myself, the other being I'm thrifty.
Pat