BarryK

Hi guys

i know basically nothing about the valve train as it's an area I haven't had to deal with .....yet, but that's about to change so I could really use a quick education and some info.

heres the deal:

on my 100% stock '78 L82 (only 10,000 original mile car) I've been noticing two issues.
1. on first starting the car when it is cold i get a big cloud of blue smoke out of the exhaust that clears up within 30 seconds. After that it seems fine - it's only in the first start when cold.
2. If I listen carefully under the hood I can hear a faint ticking sound from the drivers side valves.

i suspected and a very knowledgable fried who has been buiding motors for 40 years kinda confirmed that the blue smoke is typical of a valve guide leakage.
he also told me that the ticking noise could be a couple of things such as a lifter not working correctly due to sludge build up or carbon build up on the backside of the intake valve from oil leaking past the valve seal keeping the valve from fully closing.

I will be taking the car to a local guy evenually for a leakdown test to confirm the valve guide issue but i'm already resigned to the bad news I'm expecting to hear.

A few questions for you now please:

1. if the valve guide(s) are bad do the heads need to come off to replace them or can this be done with the heads still on the car/

2. do i only need to replace whatever valve guide(s) are bad or do I need to do them all at once and does anyone have a clue what a job like this typically runs costwise - at lease a general ballpark figure as I realize it will vary from shop to shop.

3. if the lifter(s) are bad and need to be replaced my friend tells me he prefers the Comp Cams roller tip rockers mainly because they limit the side loading of the valve stem and this is what causes the valve guides to wear on Chevy motors. If I went with the roller tip rockers do I also replace the springs at the same time and will the different rockers fit under the stock aluminum L82 valve covers?

any other pertinent info you can fill me in on that is important please add that also since I don't know enough about the valve train to even know what questions I should be asking.

i'm NOT looking to replace the heads at all with higher performance aftermarket heads, I just need to get these heads and the valve train stuff working properly again and need to know what i'm getting myself into, what kind of costs to expect, and what items I should be looking to purchase to get the job done.

thanks for any help you can give me!

Gordonm

1. If it is the valve guides yes the heads need to come off. If it is just the valve seals they can be done with the heads on the car.

2. I would do them all. If a few are bad the rest are probably worn. I doubt with a 10,000 mile motor the guides are bad. Most likely just the seals have dried out.

3. The lifters and rocker arms really have nothing to do with each other. If you are replacing the lifters obviosly the rockers have to come off. I ran a set of roller tips on my car and they worked very well. A nice upgrade. The stock rockers are not a true 1.5 more like 1.47 and the Comps are a 1.52. This will give you a little more lift. Guide wear is still out to school on this. I have never seen any proof on this but it does make sense. I would get a set of them for the extra lift they offer. They fit under my stock covers. I did mill down the drippers in mine and use thick valve cover gaskets. I have a set of Comps SS full roller rockers under my stock covers running a .544 lift and they fit. Hope this helps out a little.

BarryK

thanks Gordon.
the car sat for a number of years unused before I got i so the idea of dried out seals is very possible. I guess no way to really tell if it's the guides or seals until i have something that knows about it look at the car though. I'm assuming a leak down test would probably show the same symptoms on either the seals or the guides so it would need to be a visually test to confirm one or the other?
Obviously I'd now prefer the problem be the seals rather than the guides costwise but with my luck.........

between the lifters, rockers, etc I'm clueless, I just related what he told me........
you mentioned the roller tip models give extra lift compared to the stock ones. On a completely stock motor with the stock cam what advantages or disadvantages would this make?

Gordonm

A leakdown test will not show if the seals are bad. It just shows if your cylinder is not sealing properly, bad guides or rings. I can bet the seals are bad if it sat for a long time. They are quite easy to replace and I would do this before looking into the valve guides. It is rare for a 10,000 mile motor to need valve guides. The seals will probably break off as you are removing them. Not a hard job just time consuming because there are 16 of them and you have to remove the valve spring on each cylinder. Couple of hours should be enough.

Advantges: You will see a little more HP with a set of 1.52 rockers. How much on a stock engine? maybe 5 to 10 HP.
Daiadvantages: None. Just lighten your wallet a few $$$

stingr69

Valve SEALS are shot if they have not been changed before They are little tiny rubber O-rings that fit against the valve retainer. They have rotted away by now. The heads can stay on for this.

Valve GUIDES are serviced as part of a valve job and involves a lot more work as the entire top end of the motor comes apart for that. I doubt you need that with the low mileage.

I would also advise the Comp 1.52 cast steel roller tip rockers. They are about $145 or so. I have them on my L-82 and on my DZ-302 and they are all I would use anymore. They will fit under the stock rocker covers even with the drippers in my experience.

Replace the valve stem seals, rocker arms and pushrods and see if that takes care of the issues. I would do the job myself so I have no idea what the labor would be. The parts come to about $250 bucks so maybe $500-550 for the whole job(?)

-Mark.

-Mark.

Paul L

Barry,
I had both o-ring and umbrella seals on my 1979. They only lasted about six years. When we replaced them (compressor method) the umbrellas were so brittle that they shattered into pieces on handling. We used Crane seals (~$25.00 a set) that snap over the top of the valve guides. They are held in place via a circular spring and no machining was required. I believe they were a viton compound. It's been a couple of years now and the car is just fine. Oil consumption went from about a quart every 300 miles to a quart every 1,500 miles.

I doubt that you need guides.

BarryK

awesome, thanks guys, that's a big help and quite a relief to hear that it's quite possibly the seals rather than the guides in both cost factor and labor factor in not having to remove the heads.

i'd remove the heads myself if it was the guides and take them to a shop but still, after putting the motor back together in the spring I wouldn't relish the thought of having to take everything all apart again - way too much crap to deal with on these later model cars with all the A.I.R and other emission crap and vacuum lines compared to me '65.

Sounds like I found another winter project i'll need to dig into and something new to learn how to do.......

it's always something!

noonie

You will get contraversy about using the viton positive seals vs the umbrella seals. Some people insist that the viton promote valve guide wear, others swear by them. Your choice, but go with at least quality umbrellas.

With that mileage the engine would have to have been run without oil to wear the guides.

As far as the lifters being noisy, you can put a cleaning additive in the oil for a minimum amount of miles to remove sludge and then change oil a couple of times quickly. Follow product directions closely. The lifters should also not be worn at this mileage.

You probably would enjoy oing this yourself

Paul L

Noonie is correct. Some people argue that the positive seals wipe the valve stems too clean of oil and this leaves the inner guide surfaces inadequately lubricated. I am not technically competent to say that this is correct or not but the 1979 has been going strong since the install three years ago. Perhaps some folks who build engines can comment.

simpson36

I second the dried out seal disgnosis. Guides aren't worn at 10k.

Something to try is 'high mileage' oil. If the seals are not broken, but just hard, the special additives in 'high mileage' oil . . I use Valvoline . . . will soften the rubber and the seal MIGHT start to work again.

Worst case is you're out 12 bucks.

jackson

28 yrs, 10K miles, blue smoke on start, faint ticking.

UNlikely guides/valve stems are bad ... if so, pull heads & have "thin-wall bronze liners" installed ... not full guides, not coiled inserts, not knurled.

Likely seals are bad ... suggest replace them.

Springs go bad with either OR time / mileage ... they'll take a set and get weak ... that MAY be source of ticking ... suggest replace them with inexpensive set of either stock or "Z28" springs. Even a brand new spring will tend to take a set & go bad if it sits for a long time while compressed ... when motor not running, many springs are compressed to some degree. Bad spring(s) can be source of ticking.

UNlikely pushrods are bad at such low mileage ... but closely inspect each end for collapse/fine fracture & overall for straightness. Bad pushrod(s) can be source of ticking.

If lifters are bad ... they MAY be cleaned .. or replace them ... you can put new lifters on an old cam but not vice versa. Breakin-in new lifters as though cam was new too. Bad lifter(s) can be source of ticking.

UNlikely rocker arms are bad at such low mileage. I am not a fan of roller tips ... I like "shoe" as in stock or full roller ... my bet's on stock for this application. Bad RA(s) can be source of ticking.

Also, it's not uncommon for an exhaust manifold leak to be mistaken as valve train noise (ticking).

BarryK

ok, first on seals......... are they hard to replace?
where can I dig up step-by-step instructions on replacing the seals and do I need any special tools?

same questions on springs and removing and cleaning or removing and replacing valves.

thanks in advance. This is very helpful so far since like I mentioned, I have ZERO knowledge and experience in the valvetrain area yet

Gordonm

I have the tool for removing the springs on the head. I also have a hose fitting to stick in the spark plug hole and hook up your compressor and this way the valve will not fall into the cylinder. The spring compressor fits over the spring and you turn a big thumbwheel and it compresses the spring. Remove the valve keepers and the spring will come off. This gives you full access to the valve seal. There is more to it than tha tbut you are welcome to the tool if you need it. I'll see if I can find a pic of the tool so you know what it looks like.

Here is one on Ebay like I have. This works for stock size springs but when you go to a larger spring it does not fit over them. This should work good on your heads. http://cgi.ebay.com/ebaymotors/K-D-2...34075608QQrdZ1

BarryK

thanks Gordaon but it looks as if that tool isn't very expensive so when I'm ready to tackle this thing i might as well pick up one to have and add to the toolbox. Between both cars I may need it again in the future.

I don't have an air compressor so I guess i'll need to figure something else out to keep the valve from falling in or i'll have to get an inexpensive compressor also

Gordonm

What you can do is shove nylon rope in the cylinder hole and then slowly rotate the engine over and compress the rope up against the valve. Then remove the spring. This will also not allow the valve to drop into the cylinder. I prefer to do compressed air but if this is all you have it will work.

Paul L

Barry,
The nylon rope trick does work. Just be advised that if you drop a valve, the heads come off. So be careful.

BarryK

Paul
you know what? I would have been fine but now that you had to say that you just about guaranteed that I'll drop the valve down now.....

Paul L

Barry,
I was not trying to jinx you! If you are going to try the valve spring change I recommend that you get a magnetic rod tool (about $5.00). The little keepers that keep the spring retainers in place have a habit of getting into places they shouldn't be (e.g. oil return passages). Of course it is prudent to use rags to prevent that. But when you compress the spring it is much more convenient to snag the keepers with the magnetic rod than have them drop...somewhere....

http://cgi.ebay.com/ebaymotors/Teles...QQcmdZViewItem

BarryK

cool, good idea Paul.

i'm not prepared to start the project yet - probably in a month or two when the car is parked for winter storage (right now Linda is enjoying driving it too much now that she finally gets to enjoy the car ).
At that point I'll probably post back and ask for what "shopping list" I need to work up in regards to tools I'll need, good replacement parts, etc so I can get everything all at once.

Paul L

You had to mention that W word! I have tried not to think about it but it was 34F this morning. Looks like one or two more drives this year and then storage time. The summer passed so quickly. I probably logged only about 600-700 miles.