Well, I finally got the old pickup running about two months ago. Started up without too much drama and just a few little things that needed attention. It's a 92 Chevy pickup with the TBI 5.7. Not a screamer but is a decent tow rig for my needs. Basically, the work that was done to it was: Valve Job by a supposedly knowledgeable machine shop (I was fairly happy to get the heads back quickly, then the owner asked me if I was using a stock cam because "the old valve springs were pretty weak and it took A LOT of shimming to get the right pressure out of them". He wasn't kidding. I stacked up the shims in one stack. It was just over 2 INCHES TALL! Just for the record, that averages more than .125 of shim for each spring!) New oil pump New Edelbrock Performer cam and lifters Installed suggested Edelbrock valve springs after I got the heads home Cloyes double roller timing set TFS TBI spacer MSD coil Shorty headers Flowmaster Cat-Back system Did the standard cam break-in procedure, started it, ran it at 2k RPM for 20 min then varied the speed from 2k to 3k for another 15 min. Shut it off, checked all the connections and for any small leaks. Changed to fresh oil and filter. For the first 200 miles or so everything was great. Good milage, good power, no smoke from the exhaust, not one drip of anything on the ground. I live fairly high up in the mountains and there is a VERY twisty road to get up here. The other day, I noticed the factory oil pressure gauge dancing up and down depending on how tight a turn was. NOT GOOD! Got it home and checked the oil. 3 Quarts to fill it back up! Now, for about the last 300 miles or so, I've noticed some blue smoke at start up after sitting all night, sitting for about 5 hours before lunch and again when I start it up to leave work. Total miles since starting it back up is about 800. It may be my imagining things but it seems to put out more smoke week to week. Yes it is blue and yes it smells like oil smoke. I'm assuming it needs new valve seals due either to something I did putting it together or the machine shop did when they installed the plastic umbrella valve stem seals. 50/50 chance either way. I can't think of any other reason it would burn oil this way. uzzled: So, my question is this: Since I really only want to have to do this once, is this the correct procedure for installing the plastic umbrella seals? Expose the seal by taking off the valve cover, rocker arm, valve spring and spring retainer, remove the old seal (supporting the valves of course), put a dab of assembly lube on the inside of the seal and press onto the valve stem. Push it down until it sits against the valve guide boss or basically as far as it will go without breaking or cracking the seal. If not, can someone please enlighten me? :Comp: Thanks
What about the rings??? How many miles are on this truck? If the valve springs were that worn out, how do you know the rings are not roached? It seems a lot more likely that you've got ring wear problems rather than something wrong with your NEW valve job. Have you tried a compression check?
Thanks for the response John. Couple of things I should add about the truck. It only has 86k miles on it and yes, those are correct. It never used more than 1/2 quart or less between oil changes and never smoked at all prior to this. It's never been overheated or revved hard. Basically up to now its been my wife's truck and has been well taken care of. The only thing I can think of that causes these symptoms (oil smoke after sitting or during high vacuum situations such as decending steep hills, which I do every single day) is oil getting past the valve seals. Any thoughts on how to properly install new seals? I will probably be pulling it apart next weekend to do the new seals. This is my daily driver so I need to fix it and it can't sit during the week. Thanks! :beer
If it smokes only at start up it is probably valve seals or possibly guides. Ask the machine shop how the guides looked. If they are worn out, they can cause the seals to wear prematurely and leak. Smoke on heavy decel could be caused by a pcv valve not operating properly. Pull the valve out and shake it-it should have a good click type sound. Clean it out with carb cleaner until it is working well. Rings will commonly cause more of a problem on heavy acceleration under load. I would also check for oil leaks at the valve covers and rear of intake. They may be enough to drop the level but not hit the gorund if the oil is burning off on the hot block. You have the right method for replacing the valve seals, but I don't think there is much you could have done to damage them to the point you are saying just by putting in new springs.
Couple of things strike me as odd on this one. First...if the springs were that weak - why didn't he call you before putting it all back together?? o No: Stock springs were VERY marginal at best!! When you start shimming them like that, you run into a very real possibility of coil bind. If there was coil bind, you could have cracked the top of a guide(s). Next...it's also entirely possible, that all those shims were there because he sank the valve seats way too much. Were there shims under every one of them? I'd get some new springs....only $2 a piece or so. THEN, put the new valve seals on. Only bad thing could be if he did sink the valve seats too much - you'll need to know what the current spring height is to make sure you do have the right spring pressure closed.
Had he called about the springs, I would have brought him a set of good ones to put back in, he just never called. He asked me if I planned to reuse the stock cam because HE was afraid of coil bind also. Kinda made me angry he didn't call first. I would assume that had he machined the seats too far, the chances of coil bind would be much lower but who knows? I guess my biggest question with this is how good a possibility is there, considering the shim issue, that either of us cracked a seal (the ones he installed are the plastic umbrella seals) at original installation by his shop, or possibly when I replaced the springs? The guy mentioned that the original guides were pretty worn and he did replace them with new iron guides. I could see that the guides looked a bit different than the guide boss or whatever one would call it around them so I do believe they were replaced as he said. I replaced the springs right after re-installing the heads. The ones I put in are the ones Edelbrock recommends for the Performer cam. While I am not sure I was able to measure the installed height exactly, it's pretty close. I know, I know. Close only counts with hand grenades and horseshoes. The engine revs to about 4500 RPM with no complaints or valve float so I believe they are REALLY close. The cam and intake really run out of breathing room about that high and, as this is a truck I drive everyday, I haven't built it to be a screamer. Just something with a little extra HP and torque to pull my trailer up the hill when necessary. The springs I installed are supposed to have 125 lbs on the seat and approximately 310 at full lift on the cam. I did check the valve train geometry and everything appears to be ok. I guess maybe I'll have to spring for a true measuring tool so I can be sure the springs are set just the way they are supposed to be. Oh darn, another new tool...... :laugh: Thanks for the help guys. I really do appreciate this. It will be a bit more difficult to do this in the truck than it was on my engine stand. :af: Phil
was gonna' be quiet but.... In my younger days what I and my friends found was that a lot of the local "hack" machine shops did, was exactly (or as little) as you told them to do. So when you went in and had a valve job done and left new springs thats what you got back... No new valve seals... NONE... Had this happen on 3 different sets of small block Chevy heads before we started taking the valve seals along with the new springs to the shop for work. Just a thought as puff of smoke on start-up is most likely dead valve seals... regards
One would think for the $400 I paid this machine shop they could have included new seals. I am sure I have the receipt around somewhere for the work and I could check but I think maybe come payday I'll pop for a new set of seals and valve cover gaskets. :af: What a pain. Thanks again for the help guys. This board rules! :beer
Sounds like you found a real ace machine shop, I wonder if he used the right size guides when he replaced them. Just a thought........... Good luck and how's that 4-4-2 ?????
The 442 seems tobe more like lawn furniture than a project, If you can believe this, my wife talked me into buying a 67 Toronado! I guess I'll have to keep 'em both!!!
Trying Not To Scream!! Somebody please, oh please tell me these things are something I just don't understand. The pic below is what was installed on each valve stem, I can only assume as the seal. New, I am replacing them with Comp cams umbrella seals. Either this is the single worst case of no damn clue what they were doing, or the worst case ever of I have no idea what I am talking about. Please, if it is me not knowing what I am looiking at and talking about, clue in the clueless. Otherwise, I really feel like I got hosed big time by my machinist! :spank: :af: :blast: ou:
Trying Not To Scream!! Somebody please, oh please tell me these things are something I just don't understand. The pic below is what was installed on each valve stem, I can only assume as the seal. New, I am replacing them with Comp cams umbrella seals. Either this is the single worst case of no damn clue what they were doing, or the worst case ever of I have no idea what I am talking about. Please, if it is me not knowing what I am looiking at and talking about, clue in the clueless. Otherwise, I really feel like I got hosed big time by my machinist! :spank: :af: :blast: ou: Well, I can't seem to get the goofy pictures to work. Let me try to describe these. They appear to be small rubber gaskets, similar to an O-ring. The thing that makes these different from an actual O-ring is that these have square shoulders, flat top and bottom and flat sides. They aren't round in cross section. They fit the valve stem about like you would expect an O-ring to fit. Needless to say, rather than stopping any oil from running down the stems and into the chambers, they just rode up and down on the valve. They aren't nearly big enough to stop any oil from running over the top of them and straight down the stem to get sucked into each chamber!
What you are referring to is a stock Chevy setup. Those help seal, IN ADDITION TO the (real) valve seals. Depending on the shop, you could have a variety of different types of seals. Stock Chevy valves come machined with 2 ring grooves at the top side of the valve. The O-ring rides in the lower of the grooves (the valve locks go into the top groove). Some places use regular umbrella seals, some use the Viton style (which are a very good seal), some have a hard plastic seal on the exhaust side only (along with a rubber seal of some type on the intake), and some machine the tops of the guides for a positive locking seal. Believe it or not - some of the old SBC's came ONLY with those little O-rings!! But....they had very thick guides.
Thanks Scott! These were actually quite a ways down the stem of each valve rather than riding in the grooves and there were no other seals on any of the valves. The new umbrella seals I am installing seem to be either a very soft plastic or relatively hard rubber. :laugh: Kind of hard to say which. In any case, I anticipate that I should have my highly embarassing smoker back to a non-smoker status at startup. By the way girls and boys. If you have a gravel driveway, put something under your car (blanket, card board, steel pan, etc.) to catch the elusive little valve keepers that act like Jumping Beans! Take a tip from Uncle Phil. They are HARD to find in gravel, under the car/truck! ou: I guess I won't go down to the machine shop for a little discussion with the guy. Thanks again!
Been there...done that. :laugh: Two words....... "Big Magnet"!!! :TU: Try finding 5mm keepers from some foreign job when they go BOING!!! :eek2: ou:
