Valve stem seals info needed and is it worth while in my case?

[scrap--metal]

So I've read a lot about whether a guy should run, reuse, or get rid of the original oring style stem seal, and it seems there are a lot of opinions on that, but I figure at high mileage I don't think it could hurt to run both.

I ran both in my Monte Carlo.

 

[SirRobyn0]

Good news bad news morning. I got the starter banged out in the Jeep so that is done. I decided I would gather everything I need to do the valve seal work, and it'll be tomorrow mornings project. I'm doing this on the farm and there is no where under cover for me to work right now so the weather might throw me, but tomorrow morning is the plan. Well I decided to pull #7 plug just to see what it's done in since I changed it last weekend, it's been about 120 miles.

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That's pretty bad for not much mileage, so because of that I think I'll likely be going back to the original plan #7, just do seals on #7 and see if that stops the fouling. if it does, and I still have issues with the mis after a hard run, I can always go back in and do springs later to try to fix that. If not I can send the springs back, put the $40 in my motor fund, and go from there.

 

[Bextreme04]

@75gmck25 I read reviews on the cheaper tool last night and did see that they are not really all that great. I might see if any of the parts stores can loan me a better tool. Look I'm a tight *** and I don't wanna spend $60 on a tool to do two valves, but also since I'm a first timer I don't wanna waste a bunch of time mucking around with a tool that's being difficult, so we'll see what happens.

@Grit dog IDK in which thread I posted this but I have done a full comp test since this all started happening. Without checking my notes I don't recall the specific readings but they were all just fine. Of course a good compression test is a good sign, but it is possible to have a damaged oil control ring, but still have good compression ring, it's not normal but can happen. My bigger concern isn't the plug fouling and misfiring that occurs after it fouls, but the misfire that occurs after a hard pull up hill. What is that from, oil past the guide temporarily causing a mis? could be... A weak spring? maybe.... Seat? possible. IDK I've got to start somewhere, cause it doesn't show on a comp test, and it's not a tune up issue, so maybe it is all just oil control. We shall see.

I did the exact same thing. I was being a cheap-ass and also needed it RIGHT NOW and couldn't wait for it to be shipped. No one had one local to me, so I got the bar one. I've used it on three sets of heads now and it is a total PITA. The more expensive one is MUCH easier to use and faster. Being able to lock it over center to get the valve retainers out and new ones in is a huge plus. Also the bar one tends to not press the valve down evenly and makes it hard to remove and install the retainers. You have to physically hold the bar down the whole time you are finangling the retainers, so it basically requires three hands to do easily. The over center tool fixes all of those problems. Like I said, it is totally doable with the bar one and that's what I have and use... but I regret not getting the more expensive one every time I do.

 

[Bextreme04]

Good news bad news morning. I got the starter banged out in the Jeep so that is done. I decided I would gather everything I need to do the valve seal work, and it'll be tomorrow mornings project. I'm doing this on the farm and there is no where under cover for me to work right now so the weather might throw me, but tomorrow morning is the plan. Well I decided to pull #7 plug just to see what it's done in since I changed it last weekend, it's been about 120 miles.

You must be registered for see images attach

You must be registered for see images attach

That's pretty bad for not much mileage, so because of that I think I'll likely be going back to the original plan #7, just do seals on #7 and see if that stops the fouling. if it does, and I still have issues with the mis after a hard run, I can always go back in and do springs later to try to fix that. If not I can send the springs back, put the $40 in my motor fund, and go from there.

I'm honestly betting with that much fouling in this short time, you probably have broken rings in #7. Mine had the miss and detonation issues and also fouled plugs like that. After the motor blew completely(unrelated), I found the problem cylinder had all the rings broken into many small pieces.

 

[SirRobyn0]

@Bextreme04 thanks for all that. Yea, reading reviews and seeing people complain about the bar style compressor, the biggest complaints were having to hold it and not even pressure on the spring, like you said. That was the point I figured if I was going to do it even if it's only just the two valves, I didn't want to be fighting the tool, my first time. And heck we certainly do enough old rigs at the shop, so I'm betting it will see some use there.

My compression is good, but as we know it's not common for only an oil ring to wear out or break and the compression ring is still ok, but it is possible. I just don't see how enough oil could get past a valve seal to foul a plug in 120 miles. It wasn't fouled out, but looks like it's getting close. The only thing is if the seal isn't good and the drain back passengers in the head are clogged, then maybe. I will be checking for that. It's worth a shot and I feel doing the one cylinder is trouble shooting at this point. If it turns out to be rings that will be the end of the 305.

A few people have mentioned that it could be the intake manifold sucking oil from a bad gasket and I did plug the PCV line, fired it up and there is no measurable amount of vacuum in the crankcase which makes that unlikely. As a side note I have hardly any blow by at all. Well I know tomorrow after I do the two seals, and I'll know even more next week when I drive it and can read that plug again.

 

[SirRobyn0]

Well last weekend did not work out. I just never found the time. So I decided on Monday that I'd schedule myself out for part of the day today (Thursday) at shop to get in there and see what happens.

Figured I'd tackle #7 first see how it went and decide if I'd do more. With the rockers off I filled the cylinder with about 100psi of compressed air. The amount of leakage was concerning. Not really a leak down test, just listening to air escaping somewhere. I could not tell if it was going out the intake, exhaust or past the rings. I even had one of the other guys that is pretty sharp take a look. No idea. So I pulled the air line out, put the rockers on and ran a compression test again. 170psi. Exactly what I got last time according to my notes. So I decided at that point I'd only be doing seals on #7 and no springs. Checked the drain back ports which were clear. Intake had a what was left of the factory stem seal no umbrella. Installed umbrella and new factory seal. Exhaust, here's where it gets interesting, it had an old umbrella seal on it and what was left of the factory seal. No one would put an umbrella seal only on the exhaust only so my assumption is the umbrella on the intake disintegrated. Put it back together and installed a new plug on #7

Not to get to far off topic but I'd taken half the day off encase I had trouble or decided to do all the seals, so only doing one gave me time to open up the rear end and find out worn it is and my true gear ratio, plus a number of other smaller tasks.

At one point in the past I'd changed the plug and driven it in to work, and pulled it out. By then it was already starting to turn black (about 20 miles). Tonight I drove home the long way (about 30 miles), hit some traffic on the way out of the city that kept me idling for a bit, and then one good hill pull. I pulled the plug out at 11PM, as I had to know, because I felt I already new what I'd find. Looks about the same. As in it does not appear that the stem seals will make a difference in the fouling on #7.

Naturally I'm a little disappointed and not looking forward to finding the time, this time of year to replace the engine, or the money. Did I mention the transmission pump on my Jeep making noise? So I'll need a tranny for that sooner or later. Yea, so I'm going to need to figure out what I'm going to do. But the deal was, if it wasn't going to be a fix I could do without major surgery I'd get a rebuilt 350.

 

[Goldie Driver]

On the plus side, though,for the least amount of time and money spent, you know what you have.

And, so long as you don't mind adding oil and changing a plug or two quite frequently you could run it fir a while more.

Which is what I have been doing, without the internal experimentation.

 

[scrap--metal]

That's a bummer... Start planning for that 350, either saving money or collecting parts, and just keep running the 305. They are tough little buggers. Be glad you're only replacing fouled plugs and not ones that look like this:

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[SirRobyn0]

On the plus side, though,for the least amount of time and money spent, you know what you have.

And, so long as you don't mind adding oil and changing a plug or two quite frequently you could run it fir a while more.

Which is what I have been doing, without the internal experimentation.

Of course I wanted this to be the fix, but knew that at the very least I came away knowing for sure where the issue lies. And that's good at least when I do replace the engine I will not be wondering if it's unnecessary time and money.

I'm not opposed to managing it. I've managed oil burners in the past, some for several years, my hang up is the missing after pulling a long hill or towing the trailer, it's not that I so much object to the sensation at idle as I think it's doing when on those hills as well, it's just at higher RPM it's hard to feel a weak cylinder, and is more noticed as a lack of power. It's not a severe power loss but it is there.

I think my next thing is going to be playing around with one of those anti-fouler things again. My main goal in doing that would not be to eliminate the fouling but to see what effect it might have on the miss.

I've wondered to myself and I'm going to voice this now and see if anyone else has an opinion. My ESC is not functioning I need to get the knock sensor fixed and the EGR ports in the intake are plugged. As you likely know the base timing is 4BTC. So I'm running basically no advance except mechanical. I've wondered if I had more timing at idle if that would help with the roughness after hill pulling. Or maybe at this point I'd just be playing with fire and should leave it as is.

 

[SirRobyn0]

That's a bummer... Start planning for that 350, either saving money or collecting parts, and just keep running the 305. They are tough little buggers. Be glad you're only replacing fouled plugs and not ones that look like this:

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Yes, I don't have that going on and as much as it irritates me to have problems at least I can still drive it. And I have to admit that I've worked the little 305 pretty hard. I've never abused it, and always taken care of it but I have worked it hard too. It's just wearing out out and on the back side of time....

 

[Rusty Nail]

@SirRobyn0
Don’t recall if you posted this, but have you checked compression on #7?
If it’s fouling plugs due to low compression and oil getting by the rings, replacing valve seals seems an effort of diminishing returns.
If I’m thinking right, anyway.

I started wondering about the intake manifold. #7 is a great leaker of many various fluids...after sustained high rpm operation..when was the last time you had the intake manifold at a close look?

 

[SirRobyn0]

I started wondering about the intake manifold. #7 is a great leaker of many various fluids...after sustained high rpm operation..when was the last time you had the intake manifold at a close look?

Funny you should mention that. Today I was doing some fence work on the farm and thinking about intake. A number of people have mentioned the intake thing and I have said it seems unlikely because with the pcv plugeed off and the engine running there is not even the smallest bit of vacuum at the breather. IDK if you know about this but the magnum Chrysler engines had, for lack of a better term a belly pan on the bottom of the intake manifold in the valley, and the test we used for those was to fire them up and run them for a few minutes with the PCV plugged off and see if even the smallest bit of suction / vacuum developed.

Of course the thing about that test everything else in the engine has to seal up properly, including dipstick, and fill cap. So it's certainly possible that the test simply did not show it. BTW in the 4 years I've owned the truck I've never had the manifold off.

I will think about it some. If I decide to pull the manifold, that would be an opportunity to clear out the EGR passages as well.

 

[Rusty Nail]

The egr passages need cleaning he says.
Hold on.
After "sustained high rpm operation" - you let off the throttle and the plug fouls when the egr should be flowing. I dont believe in coincidence but only because there is no such thing.




One time, in a good shop I worked at, I ended up fixing the lead tech's infamous "comeback queen" he couldnt figure out.
A six cylinder Ford van.
Long story short he'd "fix" it again and it always came back misfiring...

I insisted he let me have a go at it one time it came in and I messed around and fixed it after owner agreed to order the updated part.

See Ford recalled the intake manifold and issued a TSB , turns out reading was for the win. It had moving flaps inside of it...egr flaps?

Eww. I know, gross!

I understand the differences of a 300 ford v6 and your sbc but I think the baseline principals set forth in that story may hold water here as well.
I hereby forward the notion that perhaps resealing the intake manifold would yield better results than changing even one valve guide seal...Irrespective if its' assigned cylinder.

Mmm hmm.




That guy's name was Mickey

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[SirRobyn0]

The egr passages need cleaning he says.
Hold on.
After "sustained high rpm operation" - you let off the throttle and the plug fouls when the egr should be flowing. I dont believe in coincidence but only because there is no such thing.




One time, in a good shop I worked at, I ended up fixing the lead tech's infamous "comeback queen" he couldnt figure out.
A six cylinder Ford van.
Long story short he'd "fix" it again and it always came back misfiring...

I insisted he let me have a go at it one time it came in and I messed around and fixed it after owner agreed to order the updated part.

See Ford recalled the intake manifold and issued a TSB , turns out reading was for the win. It had moving flaps inside of it...egr flaps?

Eww. I know, gross!

I understand the differences of a 300 ford v6 and your sbc but I think the baseline principals set forth in that story may hold water here as well.
I hereby forward the notion that perhaps resealing the intake manifold would yield better results than changing even one valve guide seal...Irrespective if its' assigned cylinder.

Mmm hmm.




That guy's name was Mickey

For the record I have no evidence that the misfire after sustained high RPM operation is the same cylinder as #7, which is the one fouling. Of course it very well could be. The misfire after high RPM, clears after a few minutes of idling or lower RPM operation. When #7 fouls out it's a steady mis at all RPM, now of course it could be that if #7 is seeing enough oil during or right after high RPM it might clear it a few times without fouling.

Well if I do pull the intake I'd at least end with cleared EGR ports.

 

[Rusty Nail]

but 5 and 7 are next to each other
A guy can switch those wires on the cap and not notice.
Coincidentally 5 and 7 are next to each other at the intake manifold and there aint much gasket separating them...wasnt much 40 years ago anyway..
Does the EGR even work?
Didja test it with a vacuum pump?
Didja try re-introducing the crankcase gas via the pcv valve? The carburetor needs that vapor mannnn...

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Remember Smokey Yunick made that fancy manifold?

I think we're barking up the right tree but i'm starting to wonder if you havent made these troubles for yourself , dude.

Was it 5 and 7 or 4 and 7?