I recently had a rough cold idle deteriorate into low power, always rough running, lots of smoke and high oil consumption. Lots of oil in the valve cover breather tube and air filter and a dancing loose oil cap confirm the need for at least new valve stem seals. I've never done this before, so I wasn't sure what to expect. Anywho, I got the nuts and spring off the first intake valve and was ready to pull the seal. I had read a few different methods of getting the old seal off and I was anticipating at least some effort would be needed. Well, the entire valve guide with the seal on it just lifted out of the head with my bare fingers - no resistance whatsoever. I go to the exhaust valve and, indeed, I have to pry a bit on it to get it off the guide and over the threads of the valve - and the guide stayed firmly in the head. I compare the two seals (new seals are still in transit) and see that the seal for the intake valve (still on the guide in my hand) is beat to heck - cracked and missing the actual seal component.

My question: How do I deal with the loose valve guide? I'm guessing that the fact that it could move freely in the head lead to the seal failure, but will a new guide fix this?

Thanks for any help,

K.C.

84 300D, 243k

Unless you are stuck out in the middle of the Sahara, you need to remove the head and repair it. Hate to say it but the guide is the least of your problems with the blow by situation.

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87 TDT 286k
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83 SD 201k
83 D 286k
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00 122HP FLSTF
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"Danger takes many forms"

That worn and loose valve guide will cause a huge about of blowby...
so unless you do a leak down test and find that you have excessive blowby from the lower part of your engine.. rings, hole in piston, etc... then taking the head off and fixing the valves and guides and valve guide seals may be all you need.... that sure made taking the head off sound easy ... LOL

It would probably be cheaper to find a good used engine.

How do you guys figure that blow-by is caused by loose guides??? Blow-by is caused by cylinder/piston/ring issues. Blow-by is crankcase pressure created by combustion pressure leakage into the crankcase.

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

Are there air passages which connect the lower inside of the engine and the air in the valve cover ?
How would one who is looking at the indicators which he has mentioned determine that it was only the lower engine situation causing them ?
Would a turbo engine with a loose intake valve stem guide/bad valve stem seal cause excess pressure in the valve cover compartment ?

Save for the rough cold idle, the engine ran very well prior to the rather quick onset of the other symptoms. The other signs of bad valve stem guide/seals really only came on over the last couple of weeks. Though there is no 100% guarantee, I'm working on the assumption that the lower end is OK.

So.... I appreciate the input so far. As with all repairs done by those of us without bottomless pockets or wads of free time, I have to consider those things versus the goodness of the car, future headaches, etc. I understand that the safe and sure route would be to pull the head and have a valve job done (any price estimates on having that done, assuming I did the pulling?). In my mind, further down the list of (read less safe and sure) fixes would be to just tap in the first oversize valve guide with the head in place and move on. I see that they have an OD of 14.2 versus 14.0 for the standard. I have a good machine shop that could take some off the OD if needed. Again, I realize this is not the ideal, but is there anything standing in the way of doing this?

Flame suit is securely on...

K.C.

Metric would charge about $500 to replace the exhaust valves, guides, seals, properly lap the seats, touchup the intake valves, pressure check the head and take a skim cut on the face if necessary.

It's a thorough job and there will be no questions when completed.

At that mileage, Metric will strongly urge you to replace prechambers if you intend to keep the vehicle more than 50K or so. That adds another $300.

I think you should pull the head and have it repaired. Just trying to pound in a new guide with the head on is probably not going to work. Talk to a machinist familiar with these engines and see what he thinks. There may not be a guide large enough to do what you need. Then it is new head time.
Forced has a point, you might find a good engine at a reasonable price and just install that.
The labour to replace a head gasket on that engine according to my labour guide is 12 hours.

I would remove the head and find a really good machine shop at this point! You need to get a professional to go over your head first. Blow by is most often caused by worn piston rings but you need to start with the head first and I would not recommend just pounding another guide into it and expect that to solve your problems! You obviously are concerned about your car and you will make things worse if you nickel and dime it from here! Valve guides that are in this condition get this way for a reason. Find out why with some professional help!

What does a valve guide do ?
If one were so loose that it would come out with finger pressure then what was that allowing to happen to the valve to seat relationship and for how many repetitions ?
I have never heard of putting a new valve guide into a head with the valve right there... and the head still on the engine... access to both sides and a good press and prep man seem to be necessary for this...

Yes. The engine ventilation connects the bottom end to the valve area. Older cars had a road draft tube that vented the crankcase directly. The advent of directing crankcase gasses to the valvecover was to ease access to the gasses to direct them into the intake manafold for re burn.

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

i think leathermang is right. the loose valve guide will allow the valve to assume postitions that are not conducive to sealing properly. the result will be compression leaking around the valve face and into the valve cover. mimicing crankcase blowby perfectly.

my first reaction was the same. blowby is rings, but this is also a way to get excessive pressure coming up from the oil fill opening.

the solution is not cheap, but may not involve the bottom end.

i cannot imagine that this can successfully be repaired with the head on the engine. once the guide is installed the proceedure is to cut in the valve to the seats with the correct angle established by the valve guide.

good thing you decided to fit the new seals. you are possibly minutes away from a total failure of the valve assembly.

finding a good used engine can be a problem. these are all pretty old cars. they are out there though, and if you can get lucky that is probably the best way to go.

i would look for a complete car that can be driven and evaluated that has massive cosmetic issues such as rust, a rear end collision or burnt out interior.

i have bought such cars for from 500 to 1000. much less than you will spend on the labor for a head removal and reinstall.

good luck

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

IMHO, if you tap a os guide into head, you will crack the head and/or guide, not to mention the valve won't seat correctly anymore because the new guide locates the valve stem in a different place. This will only lead to a burned valve and valve seat sooner rather than later.

You could always remove the head and replace only the guide(s) that are loose, and cut the valves and seat on only those valves, instead of replacing all of the guides and valves.

I have an 1985 euro Turbo 300TD with GREAT compression but a few months after i did my compression test i noticed fuel mileage going down hill and lots of oil burning.

Just before the compression test and all this i replaced all the bearings....main and rods with standard as the machine shop said the crank was perfect and still at standard spec.


So ive got alot more blow-by and bad fuel mileage ontop of the oil burning so i was thinking the valves too.

My plan was to pull the head and have the works done on it and check the rings even though i had 400+ psi on all the cylinders.

I was talking to an old buddy whos been working on these motors since they were new and he said i should check out the chain guides as they could be worn and cause the same effect.

What do you guys think?

I honestly think our OP here should pull his head and have it done IF he gets close to decent compression number BUT wont bad valves effect compression?

What do you guys think? am i in the same boat coz i doubt anything happend in a few months to the rings with normal driving.

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