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Reptoid Overlords

Valve stem replacement w/ head in car

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I have a puff of blue smoke at cold start.  Been that way for about a year.  The car goes through approximately 1 quart of oil in  3.000 miles(10W30).  Per a friend following in another vehicle, there is no smoke under heavy load, and no smoke after high engine vacuum(3500+RPM downhill followed by acceleration).  Oil consumption goes down to about half a quart if i use 20W50 instead of 10W30(conventional).  High mileage oil with seal conditioners seem to have no effect on cold start smoke or oil consumption.  Compression reads in the low 170's evenly across all 6 cylinders with a good tester(high 150's with the Harbor Freight tester, but still even across all 6). Did not perform wet compression test.  Gas mileage with EGR delete is around 19 to 20MPG with "normal" acceleration. 

I have a freshly built L28 on a stand.  The head is getting shaved, and I still need to get a few things such as oil pump,water pump etc.  But most importantly I have a few big purchases to complete that engine how I want it.  Mainly Headers, lightened flywheel, more clutch etc.  In other words, It'll be a good while before that engine is ready to go into any car. 

So I'm faced with making the decision to replace the valve stem seals in the running engine.  I could just live with it, and wait for the other engine to be ready, or go ahead and replace the seals.  I have a set sitting in the garage i didn't use for the other head.  I havent quite made up my mind yet.  I don't like knowing it smokes, even a little, but the fact that it's not too bad might just be ok with me.  If i decide to replace the seals, what is the proper valve spring compressor tool, and how can I tell if the springs need to be replaced while they are out? Should I just get a set with new retainers and springs and all that just to be safe?  I'll admit, removing the cam scares me a bit.  But I'm not afraid to do it. 

 

 

 

 

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This is the one that most people use with the head on the car.  If it were mine I'd check with a machine shop and see what they would charge before I bought the tool.

Somebody that has one may loan you theirs?

Image result for ohc valve removal tool

Edited by siteunseen

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Maybe the best course of action is to take the head to the machine shop if the price is right? I'll look into it for sure.

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I was messing around with one of those tools, you need to stuff the cylinder with rope to hold the valve up. FYI I tried compressed air and it keep breaking the seal when I tried to depress the spring. I tried rapping on the top of the valve to jar it loose, but no joy. There is a good video out on you tube of a guy using the tool and the rope trick.

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I was messing around with one of those tools, you need to stuff the cylinder with rope to hold the valve up. FYI I tried compressed air and it keep breaking the seal when I tried to depress the spring. I tried rapping on the top of the valve to jar it loose, but no joy. There is a good video out on you tube of a guy using the tool and the rope trick.
I've watched a video of a guy do one on a Miata DOHC 4cyl. Seems legit, but I expect the procedure to be a bit more problematic for lack of a better term.

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You can also use vinyl tubing  instead of cotton rope to keep the valve seated.

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that's the tool i have - pretty cheap for the amount of use i got out of it (did several heads, including replacing valve stem seals for other folks).

it works well enough, a little tricky on the ends where there is tight clearance at the cam towers. 

+1 on the vinyl tubing - i think it was 1/4" or so, you just need to push up the valve so it doesn't fall down when keepers are removed.

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3 hours ago, Reptoid Overlords said:

I have a puff of blue smoke at cold start.  Been that way for about a year.  The car goes through approximately 1 quart of oil in  3.000 miles(10W30).  Per a friend following in another vehicle, there is no smoke under heavy load, and no smoke after high engine vacuum(3500+RPM downhill followed by acceleration).   Oil consumption goes down to about half a quart if i use 20W50 instead of 10W30(conventional). 

I have a freshly built L28 on a stand.  The head is getting shaved, and I still need to get a few things such as oil pump,water pump etc.  But most importantly I have a few big purchases to complete that engine how I want it.  Mainly Headers, lightened flywheel, more clutch etc.  In other words, It'll be a good while before that engine is ready to go into any car. 

So I'm faced with making the decision to replace the valve stem seals in the running engine.  I could just live with it, and wait for the other engine to be ready, or go ahead and replace the seals.

Seems like asking for problems.  One mistake and your small project turns in to a big one.  Plus time spent on the valve seals is time that could be spent on the engine you really want.

Nothing wrong with using higher weight oil on a worn engine.

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I'm sort of with Zed on this one. If it ain't broke; don't break it. I would run the heavier weight oil and save up for parts. That is unless there is some risk of being ticketed for some kind of violation. Otherwise I would just run it.

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it's actually a pretty straightforward job, costs less than dinner at a nice restaurant, no huge skills needed and rather satisfying when done. the bonus is it forces you to adjust your valves - always a good thing to do on an older motor...

i think it's around an hour or so to do the whole thing and the valve guide seals are cheap. the only things that could cause you drama are:

  • dropping something into the hole of doom (cam chain area) so be sure to stuff it w/rags as soon as you take off the valve cover and you'll be fine.
  • loosing a valve keeper - they can fly when they break loose, so do it in your shop vs. out in the gravel driveway (don't ask me how i know this) also see bullet #1 for flying valve keepers
  • damaging the valve cover gasket - should be able to re-use, but if the cover's not been pulled in a long time they can stick and tear, but they're pretty cheap anyway.

that's really all there is to it for "danger/warnings" otherwise i wouldn't shy away from it at all if you want a fun little saturday afternoon project.

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I have the tool (KD-3087) siteunseen showed and I have used both rope and rubber hose to hold the valves closed.  I like rope better as it doesn't have as much give as the rubber hose.  The valves will stay completely closed with the rope.  That said, the tool went out of production quite a few years ago, but you can probably find a used one.  It works okay with stock valve springs, but I found that performance springs and retainers make it difficult to use.  The tool doesn't fit well on the springs close to the towers and stiffer springs cause the tool to flex and slip off the valve retainers.

Edited by Jeff G 78
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This is all great information, and I will definitely take it all into consideration. I'm honestly leaning towards letting it be for now, but if I do, I'll keep an eye on oil consumption to determine weather or not it's time, and move ahead on my engine build.

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4 hours ago, rossiz said:

it's actually a pretty straightforward job, costs less than dinner at a nice restaurant, no huge skills needed and rather satisfying when done. the bonus is it forces you to adjust your valves - always a good thing to do on an older motor...

i think it's around an hour or so to do the whole thing and the valve guide seals are cheap. the only things that could cause you drama are:

  • dropping something into the hole of doom (cam chain area) so be sure to stuff it w/rags as soon as you take off the valve cover and you'll be fine.
  • loosing a valve keeper - they can fly when they break loose, so do it in your shop vs. out in the gravel driveway (don't ask me how i know this) also see bullet #1 for flying valve keepers
  • damaging the valve cover gasket - should be able to re-use, but if the cover's not been pulled in a long time they can stick and tear, but they're pretty cheap anyway.

that's really all there is to it for "danger/warnings" otherwise i wouldn't shy away from it at all if you want a fun little saturday afternoon project.

An hour or sooooooooooooooooooooooo

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