For those who missed it earlier, I've been chasing a cooling system leak for a while now, thinking it was the water pump weeping. Due to the very slow nature of the coolant loss (and being the poor college student that I am) I wanted to let it go for as long as I could get away with. The coolant wasn't bubbling up when the engine was running, the tailpipe was relatively clean, the engine ran great, the coolant temp changed at slow rates (never running hot at all)...the only sign of a possible head gasket issue was the ever so slightly steamcleaned appearance of the #1 plug and the rusty color in the coolant. BUT, I've been running straight water for a while, so I attributed the rusty color to the block. Wednesday night, I was "exercising the car" after leaving Luvmy92's house, when the engine all of a sudden began to stumble, sputter, heat up, and lose coolant. :cuss

Ok, so over thursday night and friday morning I tear down my motor to repair the blown head gasket. Fortunately, the engine was in good enough shape to drive the 3 miles from my apartment to the engine research lab (very convenient place to tear down a motor...)

So thursday night, the intake gets torn down to the base intake before beer call arrives and I leave. When putting away the car thursday, the coolant level in the base intake is level with the mounting surface of the T-stat. I get out there friday morning and open the hood....and the base intake is almost dry.... :cuss

So I begin to tear it down further....I get the base intake off (after having drained the entire block) and there is 1/2" of standing water in the lifter valley. :cuss <--- there was a lot of this going on today

So, before I can pull the heads, I have to yank the headers. Well, my driver's side header comes out the top a whole lot easier than it does out of the bottom, but I have to pull the O2 sensor. Well, in the process of doing this, I rip 3/4 of the threads off of the O2 sensor because it was RUSTED to the header! The O2 sensor is only ~1 year old, but apparently the coolant loss has been a slow head gasket leak the whole time.

Ok, so now it's time to break all the head bolts loose so I can pull them. Well, the passenger side head seems all in order, no bolts too tight or too loose. Good deal. Then I go to the driver's side and hit the bolts on #1 (BTW, I'm breaking them with an old bend-style torque wrench to see what torque the bolts were actually at). The front upper and two lower head bolts on #1 come loose at 28 lb-ft. :cuss Ok, so on to cylinder 3. Well, the head bolts between 3 and 5 didn't break until 94 lb-ft (way above spec) WTF?!?!?! So I check the bolts, and they appear to have been installed using anti-sieze, so they weren't bound in the holes. The remainder of the head bolts were normal.

Ok, so I pull the heads, and all cylinders 2-8 were dry, but BLACK!!! I'm talking obvious oil leakage problems....far beyond any rich condition, or even excessive PCV...enough to have flakes of carbon sitting in the crevice volume (oh, forgot to mention the engine's been using oil ever since I bought the car, but the engine only has ~55k on it so I attributed the oil loss to my leaking oil pan gasket and the dirty rear bumper cover to a rich fuel mixture). I'll get to this in a sec. So I look in the 1 hole....um....the piston top is clean (for an engine that's been using oil). That would have been my first clue that it was #1 that was leaking IF 1) the bolts hadn't been at 28 lb-ft, 2) the #1 plug was cleaner by far than all the others, and 3) there were 3" of standing water in the cylinder!!!

Ok, so the mystery of the missing coolant and power loss is now solved. Now on the oil consumption....I disassemble the heads (I'm cleaning them, flowing them, and starting to port them tomorrow) and....um....not only are the retaining clips for the valve seals missing on all 16 valves, but the seals did't even fit the valve guide boss! They were LOOSE AND BOUNCING AROUND!! That and they appeared to be plastic...I myself have never seen a plastic valve seal. Ok, so now that issue is solved.

Now, the main problem. There appears to be relatively significant errosion on the #1 piston around the top ring land, I'm assuming due to the leak. Fortunately, it appears as though the remainder of the bottom end is safe from a rebuild, but by all rights, given the condition of this motor, I really SHOULD do a complete rebuild. Unfortunately, this all happened about a month too soon....my financial aid money comes in a month, but I can't wait because this is my only car. :banghead: :banghead:


[Modified by CorvetteZ51Racer, 8:48 AM 1/11/2003]

 

Could be a bad water pump. It needs either a small amount of anti-freeze for lubrication and anti-rust properties or a water pump lubricant added to the water. The bearings probably are shot in the WP and weeping from rust particles and lack of lube. My guess.

The steam-cleaned plug is an enigma without the other symtoms of a bad head-gasket.

BIG JIM




[Modified by BIG JIM 54, 1:19 PM 1/11/2003]

 

Nice detailed story :thumbs: How about throwing the rebuild on plastic and paying off the plastic when your financial add arrives. Good luck to ya

 

Using financial aid for your car habit... :rolleyes:

I do wish you good luck on the fix...

:)

 

So, what did the HEAD GASKET look like??? That will tell you volumes about the problem.
The valve stem seals are not a surprise; over time, heat can harden them to the point where they will not seal properly, although they should stay in place on the guide (am I misinterpreting your discription here?)
The wildly varying headbolt torque is troubling. No matter what caused it, it isn't good and could easily explain the HG problem. Usually, a HG that leaks water into the combustion chamber will reveal itself by blowing large amounts of white 'smoke' (steam, actually)out the tailpipes at start-up. The starter will also have difficulty in initially turning the engine over. You did not notice this?
Good luck with the rebuild. The bottom end may be okay if you caught it early enough, but the oil is most certainly contaminated with water (does it look like chocolate milk?)
The 'anti-sieze' on the headbolts may be sealant, since some small-block head bolts actually thread into the water jacket. (I can't remember exactly which ones....)
Wish I had a solution to your financial delema but all I can offer is moral support! (Since money is tight for you, I'd do a top-end rebuild and hope for the best)

Larry :seeya

 

Biggest problem I see is using your financial aid money for the car.....

I would get a part-time job close to the campus or something, and by a bike!

The best advise for Corvette owners is to have a good job, spare time, and dispensible income!!!!

Thats the formula for maximum enjoyment!!!!

Good luck!

 

With the engine apart, I can see that it is not the water pump...it's not leaking at all. There was a slow leak from the hose that goes from the base intake to the TB.

The engine is apart and it WAS a headgasket, which I had determined to definitely be the problem before I tore into it (I had used a bore scope to look into the cylinders and had seen a little water in the 1 hole anyway...I guess my writing it so late at night I forgot to mention that). The WP actually looks pretty good.

As far as the financial aid for the repair goes, I need to clarify that....I get a partial tuition waiver for being a research assistant. The money I'm waiting on is a refund on the excess money. The refund is somewhere in the vicinity of $3000 AFTER I pay my rent for the rest of the semester. And I do have a job as a research assistant for the school, I just don't get my first paycheck for 2 weeks. It's not that I don't have any income...I just don't have any income NOW, when I need it.

 

The head gasket looked like it was in decent shape, except for the coating of water and oil on both sides of it for about half of the circumference of the #1 cylinder. It just looks as though it was never properly torqued.

On the valveseals, I know valveseals go out. I know what heat does to rubber. But, I wouldn't expect valve seals to go out after 3-1/2 years and 55k miles. They simply should not go out that quickly. The steam was never really obvious, but then again, the Ford 302 I rebuilt in august had a smooth idle, no smoke or steam out of the tailpipe, and it had a cracked piston and a leaking head gasket (the latter causing the former). I know that 99% of the time, you should see a lot of steam, etc, etc, etc....the way this whole mess has acted, it may just be that 1% case.

Also, I have checked the bottom end, and yes, there was *some* water in the oil....very little milkshaking going on. Like I said, the car was driven 3 miles after I figured out for sure what the problem was, and that was to get it from my apt to the lab. Also, it's not like the car was guzzling down water and spitting it out all over the place like you'd expect in a catastrophic HG failure. However, it did only take about 10-15 minutes to loose about 2 inches of coolant out of the top of the radiator.

 

s/b 350 are known for getting hair line cracks around the lifter bosses in the block.When the engine warms up the cracks open up more and then leak into valley.I would definitely check for small cracks in block where the lifters go in.

 

Thanks for clearing that up about the aid- I feel much better now!

Good Luck

 

I have 7 good piston and rods from my original 1987 L98 if you end up needing one. The car threw a rod bearing on #6 at 176k miles. If your rings are good you could install them on another piston and keep them orientated the same way that they came out.

 

if you have access to the equipment it might be worth tearing the bottom end apart & checking the bearing clearances & the cylinder bore diameter. a set of file fit rings could bring everything back in spec pretty ecnomically if your worried about ring condition. in the mean time you can clean up the pistons and give your combustion chambers a good polish. also how old are your injectors? i've witnessed one engine that was rich in one cyl & lean in another from 140k mile injectors.

 

I most definitely have access to the equipment. We're waiting on parts to rebuild a Jeff Gordon motor that we blew up on the dyno. The issue is time and money.

If I pull the bottom apart, I will replace all wear items down there...bearings seals, etc, etc. The problem is (from a time standpoint) that I'm almost **** about things like bearing clearances. When I'm doing a motor, it's not enough for them to be within spec, they have to be (for my satisfaction) within about 0.0002-0.0003" of each other before I'm happy. In order to do that takes a lot of time. I also have a problem with half doing jobs. I know you might say that I'm half doing it now by not tearing out the bottom end, but the motor is still in the car. If I pull it and open it up, I won't let myself put it back together without doing a full bottom end job. But by my twisted logic, if I don't pull the block, it's not as bad as me pulling and not doing a complete bottom end job. I know the rings are fine (I checked them) so I'm not worried about their condition. The combustion chambers are getting a "polish" ;-) while the heads get ported (found 30 cfm on average across the entire lift range on the exhaust side today with 30 minutes of grinding...that was :cool: ) My injectors are ~2 or so years old...roughly 20k miles on them.

 

It's always gotta be something with us college enthusiasts :nonod: Right now, looking at things optimistically, my car will need to be off the road for at least 4 months. The Bursar just slapped me up nicely on Saturday, so I gotta see just what all the good is going to bring me when classes start up on Monday. Pretty disappointing final year--I have somewhere around 18 credit hours of non-MET electives I gotta get out of the way. Maybe I'll finally get to find out why the color wheel works like it does or just how the price of beans in China affects the price of my ink-jet refills :D

Sounds like you have a good grasp on what you need to get done to patch it all back up. Just do the usual, but take out the knock sensor. When I tore down my engine over the summer, I didn't have a problem ith any rust in the coolant--but there was a plethora of rust inbetween the cyl wall coolant passageways. Took out the knock sensor and had solid rust from the opening to the cyl wall.

Getting a set of 3M nylon-like scrubbing disks (not scrub pads but the ones that look like a bunch of nails through a board) will be about the best way to treat all the mating surfaces if nothing is getting hottanked.

Good luck, keep your beer off campus ;) and above all, calibrate your torque wrenches! She'll be back together in no time. -Matt-

 

:iagree:

 

Ah, the joys of college budgets combined with cars like Vettes.

As far as cleaning the deck of the block, piston tops, and removing the ridge at the top of the bore (which is entirely carbon right now, not a metal ridge), we have air-powered die grinders with Scotch-brite pads that I can use for that....it'll just be fun to do that while leaning over the tires and other assorted crap.

You know, I wouldn't be so strapped for cash on this motor project if my ZF swap hadn't gone ~$1000 over budget :( Oh well, such is life.

 

well,

i do not want to be mr. know it all, but in your situation i would do the following:
clean the heads and do a valve job on them (check for cracks first!)
check the block for cracks as mentioned above
buy a new O2 sensor, retap the thread and use anti seize
clean the threads on the head bolts (im not sure on your engine, but on the lt1 you have to use thread sealant!)
but her back together and use new antifreeze.

cheap and effective solution.

but that is just my personal opinion....

good luck anyways. keep us posted

 

I used a bunch of 3M roloc disks and a 90 degree die grinder. They worked like a charm getting the nastyness off from the original gasket and cleaning the tops of the pistons even though there was no need. I ran the Flepro 1010 gaskets and they leave nothing on the deck at all when you remove them the next time around.