Valve guides

[Moonunit 451]

Well, it's a quart every 200 mi. I put in a new PCV no help. I just was able to see and smell oil in the exhaust yesterday on close inspection. So, here's the question. Has anyone ever heard of replacing the guides with "53" studebaker unbrella's. Two different people told me this yesterday. I've never done this before, but I think I'd rather change the oil every 3,000 mi than add a quart every 200.

I did a compression test about a month ago when I changed the plugs and did a full tune. 165 - 175 all around. I didn't do a leak down though. Tomorrow - fuel pump . Then I'll find out which injectors are bad. It never seems to end. I need to find time to mow my yard before August sometime

 

[SPANISHVETTS]

Never heard about the Stud umbrella deal but the valve guide seals are cheap and easy enough to replace.

You need to find a shop with a special tool that puts compressed air through the sparkplug hole to ¨keep the valves from dropping into the cylinder¨. We use this method to change the valve springs on the race cars because we are not allowed to ¨open the motor¨.

 

[mike 1985]

Do your plugs look oily?


i had 2 cylinders that the plugs looked terrible when i got the car, i changed the valve stem seals with some from autozone ant it completly curred the problem. I didn't like the ex. ones so i put intakes on the int and ex. and all seems good.

As for keeping the valves you can also feed nylon rope into the cylinders then turn the motor over by hand till it stops and then the valves will stay up. when your done turn the motor the other way and the pull the rope out. Or get a valve stem remover tool and take the valve out of your compression tester and turn you AC compressor down to 40lbs and use it.


Autozone also will rent you the valve spring compressor for free.

 

[jsinga]

I think you might look a little more. Valve guide seals usually won't suck down that much oil.
Even at 200k miles and 15yrs all mine do is a puff of smoke 1st thing in the morning. I rarely put a quart in, I'm talking over 2000 miles.

JS

 

[Moonunit 451]

Thanks guys for the responses. I replaced the fuel pump and checked the injectors. They each dropped about 4 lbs and did not leak down. The car was still running like crap. Thru the OBD computer on it and there were no codes. It did, however appear that the MAF sensor was not responding as quickly to throttle changes as it should. Also the cycle between lean and rich was WAY slow and irratic.

I had pulled seven out of eight plugs and checked them the night before. They all looked good, only 40 days old (along with the rest of the ignition parts). Guess which plug I had gotten too tired to pull.

Anyway, Iwas told to go ahead and replace the O2 sensor and that there notorious for going out and not setting codes. I did no change, went after the computer tapped it a few times, nothing.

Finally, I decided to pull #8. Well i had forgotten that when I had done the tune that #8 had excessive build up on it but it was crusty and light chocolate brown. It seemed odd, but the car had been running well before and after the tune. By the way I used Bosch Platinums.

Whaen I pulled #8 what I found was unsettling to say the least.

I put a new plug in and the car runs great. I guess I'm going for the valve guides next unless anyone has any other suggestions. Thanks everyone again for your input.

 

[Moonunit 451]

Oh ya, I forgot to mention, when I pulled #8 I thru the compredssion tester back on, turned over till it hit 160 and left it there for over 10 min. Never lost a pound.

Anyone have any further input or similar experience? I'm kinda looking for some reasurance that I'm not looking at rings here:nono .

 

[bradfordsvettes]

valve seals

you really need to do a leak down test to be sure and on the compression test you should have full pressure within 4 strokes of the piston. if you have a lot of oil on top of the piston this could give a false compresion reading. leak down test is the best bet only my 2 cents steve

 

[vets4-2]

you can take the comp. gauge to bed with you and it won't change untill you release the psi! But 1qt. every 200 miles dosn't sound like a valve guide seal. How many mi.on the car? How do you drive it? If you have oil in the exhaust you probabley have a ring or piston problem. why are you checking the inj.? did you have a bad one?

 

[drcorvette]

Valve Seals and Guides

Just a note from my experiences.

When my seals and guides needed replacement I experienced very little oil consumption. My symptoms were that infamous puff of smoke and spark plug fouling approximately every 500 miles.

Got tired of cleaning and changing spark plugs so started with the cheapest thing and that was seals. This didn't cure the problem so off with the heads and did the guides. Then just went crazy from there. Down this far so did some mods to the bottom end.

But I really don't think you should be using that much oil because of a seal or guide problem.

Gary:confused

 

[BigRed]

Are you leaking anywhere?? Im mean have you actually been able to get under the car and take a look at things? You said you PCV was exhanged (assuming the old one was shot) perhaps it pressured up your seals therefore the leak. Try looking behind the bellhousing dust cover for a rear seal leak. Also have you checked your coolant? Perhaps this could be head gasket. (Oil into exhaust or coolant)

These signs are a better indication of 500 Mile 1 quart fills. I also had to redo my valve seals (Used the Hat or umbrella type) but I sure didn't use that much oil and my car a puking blue pretty bad.

 

[Moonunit 451]

Now we're getting somewhere guys. Thanks. I think . Initially I was checking my injectors cause the car was taking way to long to start. I ended up replacing the fuel pump after determining that it was leaking back. The car was still running like crap and I only had 40 days on the last tune, so it was easy to check the injectors.

When I did the tune I did a full compression test with all the plugs out. 165-180 around. # 8 was 180. I did 5 strokes each. I don't really drive the car way hard most of the time cause of traffic and cops, but when I can I romp for speed. No burnouts or racing yet, but I regularly run up to 80- 90 and have been up to 125 a few times. The engine has 114000 mi. #8 was a mess but still burning when I changed plugs. I did not do a leak down (don't really know what that is) when I did the compression test.

I have NO leakes of oil. I changed the PCV to rule out cheaply that that might be causing unusual oil consumption on the advice of a mechanic.

I'm a backyard dood, but have access to lots of equipment and advice beyond my own rather extensive tool collection. I'm talkin' to you guys cause I'm lookin' for good Vette experience vs. general mechanics. I'm not bad for general stuff into the early 70's, but now there's all the computers and on and on.

My best freind has a shop and a lot of updated knowledge with plenty of GM training and computer stuff but he's mostly into general maintnance and doesn't know everything, but tons more than me. Consequently, I also hear opinions of other ? savvy people. Sometimes I think they have good advice, (thus the original question about the Studebaker umbrellas) and sometimes not, but most of them have good expeience and thats why I consider what they say.

Cooling system is OK for the most part. I've had the car on a lift more times in the last week than most people will as long as they own one. I'm very meticulous with my vehicles and I notice any small imperfections
as far as dirt and leaks.

I'm NOT puking blue. I had to REALY pay attention in the shop to see any smoke and smell the oil during revving. You can't see it driving down the road from the driver point of view at all, nothing on start that I can see.

Sorry to ramble, but I'm trying to answer all points. Guides would seem to be the next step I guess, although I've never done any. I have access to the equipment to do them in the car, I guess without too much trouble.

Thanks agian for the responses and keep your thoughts comming please;worship

 

[vets4-2]

It sounds like you might have a bad guide. try doing a comp.test on #8 about ten times. and see if one of the times you get a bad reading. That would indicate a bad guide. Also try shorting out #8 with the car running and see if you get a change.Check the valve train for proper operation. ie bad cam,bent push rod,worn or loose rocker. on #8

 

[Moonunit 451]

Do you mean a compression test with all the plugs out? Short out # 8 for what reason? The car ran smoothly after replacing the plug. So' I know if I short it out it'll get rough. It may be a few days till I can work on it again, so I'm still open to all thoughts to consider for my next go - round. Thanks

 

[vets4-2]

ok if it ran good after you changed #8 than still do the multipule comp. test you know the problem is there,now it's just a matter of whats causing it. (CAUTION 119,000Mi) don't spend much money(over $300.) on ANY repair. the engine need's to be rebuilt!Don't despair there cheep to rebuild. What you don't wan't to do is through $300. here $300 there and come up with the same thing! (rebuild) Best of luck.

 

[Moonunit 451]

vets4-2,

Just found your e-mail. I was aware of that. I just didn't know how to do the leak down. I'm still not sure if I need to pull all the plugs to do this, and if I'm just spinning four cycles and waiting for one to come up much lower than the rest in that hole. My understanding is that in order to do a compression test properly you should have all the plugs out. I understand what you meant about taking the guage to bed with me. I hadn't considered that before. Like I say, I'm backyard.

I know that it's not neccesarily that expensive to rebuild the engine, but it is a PITA and this is my daily driver. I have had to rebuild or replace the engines in the last 3 cars I've bought with in a few thousand Mi and a few mos. of purchase. Frankly, I don't like the trend and I'm kinda sick of doing it. In no instance was there any indication of a problem when I bought the vehcles. They were all pretty thoroughly checked out before purchase and had records and yadayadayada. It's just my luck it seems. I know whats next if the guide valve seals don't do the trick.

I am kinda curious though. I have the full history on this car, confirmed by carfax. I have inadvertantly stumbled across another post you replied to that someone with 135,000 mi. was do for rebuild. I've seen several people post with a lot higher milage than that who have run their cars hard without major overhauls that I'm aware of. What do you base this advice on? And to anyone else meandering thru here would you agree that well maintained engines in this milage range are just living on borrowed time? Thanks.

 

[SPANISHVETTS]

Hi Moonunit,
Many years of operating a fleet of vehicles taught me little about predicting an average life expectancy for the SBC but I have seen the following patterns:
Major rebuild under 100,000 = abuse and/or poor maintenance.
No problems after 200,000 = excellent maintenance + damn good luck.
I do not have access to all of the old records anymore however memory tells me that the average mileage to rebuild was somewhere over 200,000. See this post.

Since this is your daily driver your cheapest way out might be to just swap out the motor . If you get everything lined up in advance you should be able to do the swap in one day for less than $1500 in parts. Look at the price of long-block engines here.

Another thought, Sell your car and buy 69MyWay´s 90 before he pulls the engine out.

 

[drcorvette]

The Mighty L98

The L98 is a work horse and a great engine. If you say the car has had regular maintanence and you had the car checked out before you bought it for major flaws then IMHO 119,000 miles is nothing!!!

The L98 is notorious for valve seals and valve guide problems. Get the seals done and take it from there. The seals are not a big expensive job. Now the guides are pretty much a top end job.

These cars are nothing but a PITA sometimes. Guess thats why we love them!!!!

Gary

:J

 

[oldace84]

Those umberella seals where a stock item on the Vega's......remember the vega's?????
Any way I use to always put them on my smal block chev's.....
they work great....don't know if they are still available though?????
FYI
tony

 

[Dave C. '04 Z06]

valve stem seals>>

If your valve stem seals are bad you may be able to check by running these tests:

1. Bring the car up to temp and let it idle for a couple of minutes. Then have someone blip the throttle. If you see a puff of blue smoke out the exhaust, the valve stem seals may be bad.

2. Have someone follow your car (or drive it if you trust someone) and put it in first (1) (if you have an auto) or whatever gear if you have a stick shift and get the rpms up to about 3000-4000rpms and then let off the gas and let the engine slow the car back down. If you get blue smoke out the tail pipe when you're decelerating then there's a good bet you have worm valve stem seals.

These symptoms can also mean worn rings, but since you did a compression check and it looked okay then the valve stem seals are one of the last paths for oil to get in there.

Another way to check for worn rings is to let the engine idle and take off the oil filler cap. Put your hand over the opening. If your engine has the "chug of death" (IE. puffing up at your hand) then you have blowby and your rings are worn.

And remember: BLACK smoke is GAS. BLUE smoke is OIL.


Good luck
-Dave C. '97 Z28
1997 Camaro Z28 w/ 454cid big block
1995 Corvette LT-1 6-speed (stock)

 

[Daryllawman]

125 a few times