Go ahead...make me cry.

[78SilvAnniv]

It took 6 months to get the 78 back on the road this past winter. I've been enjoying driving her for several weeks, but have noticed something was 'off' (not quite as powerful at lower rpm ranges, sort of lugging) and was also aware that I was losing a lot of oil, but we had no leaks.

The repairs that were done this past winter were:
Replaced the heads with better breathing ones.
Replaced the #4 piston that kissed the intake valve, utilizing previous piston's rings.
Installed double roller timing chain.
Cleaned up hose and wire routings.

Today, I noticed that there was a strong oil smell in the vette while driving. Checked oil and it was a quart low so I put in the quart.
When Kenny came home from work and I explained what I was experiencing, he went behind the vette and stuck his finger in the passenger side tailpipe...and it came out dark and oily.

Should I begin :cry now? Does it mean what I think it means?
Heidi

 

[*89x2*]

ring(s)

 

[Ken]

Replaced the #4 piston ... utilizing previous piston's rings.

Shame on Kenny! :nono

 

[mike weyman]

used parts and the inside of the engine go together like peanut butter and onions. replace the rings before they cause more grief(scored walls)mike

 

[DkBG]

Condolences on this one Heidi but Kenny is going to learn the hard way this time . Thats way too much work to go to , to go cheap on the parts . The oil problem is most likely the rings and the power problem may be too . He might want to do a compression check , just to verify that but as was said , it would be best to fix those rings befor they cause serious damage . Sorry . Cliff

 

[MMM]

I don't know how many miles are on the car, but I too suspect your rings need to be replaced. I learned years ago that it is not wise to do a valve job on a high mileage engine. Ring seal and valve seal are critical to keeping compression in an engine. As the engine wears, both items wear evenly, i.e., ring and valve seal both degrade about the same. If on a high mileage engine, one or the other is made as new (like a valve job), it now overpowers the other and oil burning occurs. I bet I have been asked at least 25 times over the last few years, "why is my car now burning oil since I did a valve job?" The valves are no longer leaking and the compression just blows by the rings.

Mike

 

[Bob Chadwick]

Heidi,

So sorry to hear about this. Do a compression test on this piston. Do it again after adding a small amount of oil, which helps worn rings seal. If the compression goes up, the rings will need to be replaced.

Bob

 

[brusso]

Pull all of the plugs and check and you'll find which one/one's passing oil. If it's number 4, the oil ring may be upside down. Also could be improperly intalled head gasket. Usually it takes a few thousand miles to get the "I just rebuilt the top end and now the lower end is shot" to happen. In either case, it looks like a tear down is in order. Best of luck.

 

[78SilvAnniv]

...it looks like a tear down is in order.

That did it! :cry :cry :cry

I think I knew it would involve another pull and removal of #4 piston.
I don't understand about re-using #4s rings, though. I thought that was acceptable.
My understanding is that by reusing the rings you didn't need to go through the period of time for the rings to seat. I thought this would be doubly ok because they had so few miles on them.
So we should have used new rings... ad

This engine is a 1997 Goodwrench with about 30k on it. We didn't replace all of the pistons/rings, only #4 (which had gotten smacked and dented by the intake valve when they kissed) This bogging and oil smell problem surfaced about 2 days ago.

Darnit...I really don't want to go through the wait of another teardown. Poor Kenny will have no relief...I'll be nagging the whole way.
Is it done yet?
Heidi

 

[Ken]

... peanut butter and onions.

Hey, I like peanut butter and onions! Honest!!

 

[wishuwerehere82]

Heidi,

It makes me sad to see your icons cry.:dance
If your rings are cracked though, a siezed engine will make you cry more. If it is #4, or any other one it doesn't matter, because a teardown is the only way to find out if your cylinder is scored as a result. Unless you have one of those borescopes.
Just curious, how did #4 valve punch out the original piston? Did one of your valves stick, or did you skip the timing chain?
Call it morbid curiousity, but I just love finding/diagnosing engine problems and fixing them so they run like new again.
Good luck

 

[78SilvAnniv]

We believe the timing chain had to much slack in it, allowing for conditions that made it possibe under WOT for #4 and the intake valve to kiss, bending the intake valve, pushrod and denting the top of #4.
Heidi

 

[Bob Chadwick]

Heidi,

If Kenny needs to take the engine apart and will give me a little notice, my weekends are pretty much free between now and mid-August, when football starts. I'd love to help him and learn something to boot.

Bob

 

[JRMaroon]

I'll second what Bob if offering.

I'd be happy to help and wouldn't offer if I didn't want to get my hands dirty.

Jeff

 

[78SilvAnniv]

You guys are the best!
Kenny is planning on pulling it this weekend.
Sat-out
Sun-in
I'll send you both an IM with our phone and address for mapquest directions.
Heidi

 

[KANE]

It took 6 months to get the 78 back on the road this past winter....
The repairs that were done this past winter were:
Replaced the heads with better breathing ones.
Replaced the #4 piston that kissed the intake valve, utilizing previous piston's rings.

Today, I noticed that there was a strong oil smell in the vette while driving.

...and it came out dark and oily.

Should I begin :cry now? Does it mean what I think it means?
Heidi

Uhhhhh.....

Oh, I hate that. I came back from Kuwait in '01 after 5 months of deployment and my fuel lines leaked front and rear. Rubber hoses...eecchhh. Tranny fluid in a pool under the car.... shall I continue????

My heart goes out to you. I understand about making repairs and not feeling the fruits of the financial pain and suffering!!! But it takes more than money to keep an old vette running - you have to be psychic too!!!

It was funny going through my tool box last night and I found the following-
3 rolls of primary wire
4 spare AN fittings
Header, hex (intake), screws, misc fasteners
Zip strips
Solder
Voltmeter
Vacuum gauge
Tefon tape
T-top weatherstrip
T-top spacers
Spare inside door lock pull
Bullet, butt, crimp connectors
Spark plug wire sections
Spare MAP sensor
Spare IAT sensor
Interior screws
Four boxes of glass fuses

Its wild because with my 1978 really needed all of those things at any given time to keep it running!!! Ughhhhh!!!!

 

[Bill75]

You didn't mention if you had the piston rod checked in #4 but depending on how hard it "Kissed" the valve, I would have it checked to make sure it was still straight if I was going thru all that work. Best of luck.

 

[Jack]

Heidi & Kenny:
Sounds like a ring to me. But the cause may be something to look into. Let's not be so quick to slam Kenny. Simply reusing rings is not altogether taboo ... its done quite often in racing ... and in 3'rd world countries ... anywhere someone's in a pinch. Done correctly, reusing old rings can be successful.

If/when you pull #4 ... verify (via machinist) that #4 ROD is absolutely straight ... it did get leaned on when piston got kissed. If ROD ain't perfectly straight & true ... it can easily shove the piston AND RING pack to one side ... causing rings to leak and possibly crack. Also check the piston for cracks/damage. Also check that the wrist pin is firmly locked AND centered ... if it slips to one side it can score a cylinder in a heartbeat ... a bent rod can push a pin to the side.

Most oil rings have 3 pieces ... a center expander with one thin rail both above and below expander ... most 3 piece oil rings can be installed either side up ... because there ain't an up or down with most 3 piece oil rings ... but pay close attention to its expander. Ensure expander ends are not overlapping one another.

When there's been a re-ring job that failed ... The second compression ring is where there's often an oil-pumping problem. They usually do have a specific top and bottom orientation. They sometimes have a barely-perceptable taper on outside diameter (taper's larger diameter toward crank)... some even have a bevel on inside diameter (bevel faces crank). Yours probably has both taper and bevel. Some second rings have a dot near gap .... this dot usually faces head. An upside down second ring can and usually will cause oil pumping.

The top compression ring sometimes has a bevel on inside diameter ... and that bevel almost always should face toward the head. Yours probably does not have that bevel. Some top rings have a dot near gap .... this dot usually faces head. An upside down top ring can cause oil pumping but not usually ... its usually accompanied by a lot of blowby back into the crankcase.

If you're gonna pull #4, I do suggest new ring pack. Believe it or not, the replacement type rings generally seat quicker than the more expensive high performance sets. Do check ring end gaps with feeler gage ... ALWAYS do it with new rings ... to little gap & rings will crack and score cylinder ... too much and it'll smoke.

If you're just doing #4 ... scour the cylinder walls with some 3M scotchbrite DARK RED ... but first lay a rag down in hole and on top of crank throws to collect grit. Better yet ... If you can find a "ball-hone" ... looks like a big (a little over 4" diameter) bottle brush but has balls of hard abrasive on bristle tips ... drop in the rag ... chuck the ball hone in a drill and spin-hone #4 cylinder ... that's better than scotchbrite. I've used both methods ... done it with motor in car several times.

If I had to toss a coin ... I'd guess that either the second comp ring is upside down or the expander is overlapped ... or a ring's cracked.
JACK:gap

 

[sherry_ridgeway]

Geee heidi
Im sorry to hear about that, however it's always a good thing to replace the rings and rehone the cylinders when ya have the heads off ..It seems that a lot of vettes of that year have the same problem..78-82 etc..Please save yourself a bit more heartache and be sure to check the drivetrain afterwards, and regrease all the rear end fittings and universal joints etc..It's very dissconcerting to have the motor running great and have somenthing go wrong in the rear end or drive train or wheel bearings ,etc..as stated many times in this forum Pm=preventavie maintence is always a good thing and somenthing to keep an eye on, of course theirs always the chance that some oil or somenthing got spilled during the rebuild and thats the cause of the smoke or oil discharge.."check the oil send unit" and lines to be sure before taking the engine apart again, I hope you find a remedy to the problem without another total engine rebuild, ..If you find that the rings are truly the problem..by all means change them and hone the cylinders a bit and install a higher compression "high domes" piston that will cause less maintence in future....Im sure I'll catch hell for this responce LOLOL.but I bielive even the "high rollers" will agree that if its got blue smoke its a ring problem or somenthing of that nature..Heck mine smokes a lil bit when i start it.."if i kept my big foot out of it then it wouldnt do that" now would it?"...LOLOL!!!..Im sure you'll get it going
keep us informed
Sherry

 

[AUSSIEVETTEMAN]

...I don't know how many miles are on the car, but I too suspect your rings need to be replaced. I learned years ago that it is not wise to do a valve job on a high mileage engine. Ring seal and valve seal are critical to keeping compression in an engine. As the engine wears, both items wear evenly, i.e., ring and valve seal both degrade about the same. If on a high mileage engine, one or the other is made as new (like a valve job), it now overpowers the other and oil burning occurs. I bet I have been asked at least 25 times over the last few years, "why is my car now burning oil since I did a valve job?" The valves are no longer leaking and the compression just blows by the rings...Mike

Mike, I agree with what you are saying. I have to do the valve stem seals on our unmolested 350. Some say just do the top end, but I say once the top end is done, the bottom end will just let it down!
Ours goes in today to have the engine pulled, should be a big day. In three weeks, I will have her back with added extra.

Sorry to hear about your Vette Heidi, especially now that your weather has improved and is now Vette-weather!
It is getting colder here in Oz, so it is time to do some major work on the old girl. Mind you our cold weather is only 20 degrees celcius!


Tony