HurstOlds1775

Ok all, this is a strange one! No compression in one cylinder of a stock 1969 L-32 hi-comp 455 with 68,000 miles. I think the heads were off it once before years ago, before I got the car. It idles with a VERY slight skip like a small vac leak. Still drives smooth with lots of torque and power (I know it's an Olds and their great!) without any smoke from tail pipe until I rev it over 3,600+ RPMs then it has a small to medium trail of oil smoke, once I let off it goes away. All other cylinders have 125+- comp in each except #1 it is 0 during dry and wet compression test. I do not have a leak down tester so I used an air hose fitting in the plug hole and returned all other plugs to their cylinders. Applied air at top dead center and air leaks from push rod channels in head, also a small amount lower block inside somewhere, (can't tell where) so it must be in the valley coming thru push rod holes anyway, I think. Very small champane bubbles in radiator with very light brown traces of foam and using a little coolant when driving a few 100 miles. No coolant in oil but getting dirty fast and pressure dropped slightly according to rally gauge. Both valves are moving up and down during turn over and with exhaust valve open air goes to exhaust manifold and with intake valve open air comes out to carb. Head is clean and draining at both end channels. Oh yea, the plug in that cylinder #1 is oil fouled but is firing. Is it a Head gasket, Intake problem, or a MASSIVE hole in the piston? I know what your going to say "Take it apart and find out" It runs so well and keeps me from abusing it I want it to last a few hundred miles to get me thru the summer then I can tear it down. I guess I'm greedy! I have never seen this before on any engine and wanted readers opinions. I say head gasket at the valley pan area had a massive blow out, just a guess.

oldsmobum

Get a little bit of oil (preferably gear oil) and give a little shot of it in the spark plug hole. Then turn the engine over and check the compression. If it is a ring, sometimes the oil is enough to seal it and give you SOME compression.

I would check your valves- I have an old chevy c10 with a 350 that had no compression at #4. It turned out one of the lifters has had it so one of the valves was always stuck a little open. All I did for that was back off the adjustment on the rocker arm and it was good for 60 psi- enough to get combustion. It might even be better now because there could have been nasty stuff built up on the open valve. I now have a little lifter chatter there but I intend to just run it until it explodes.

It could very well be worse, like a burnt up valve or head gasket. Unfortunately if none of that works you'll have to pull a head.

442scotty

You dont want to here this but....

Take it apart


Or...keep driving it and maybe you can blow the engine up because you didnt pay attention to the warning signs... Your engine is giving you a msg...you are catching a lucky break...shut her down and open her up

72 cutlass455

If you are lucky when you pull the valve cover and hopefully you have a eureka moment have seen broken or weaken springs that cant seal correctly.

HurstOlds1775

OK 442Scotty I took your advice and pulled it apart! Here's the update. Pulled the intake off to check all gaskets. The turkey tray was fine and appeared to seal without leaks. Pulled valve cover and checked springs for #1 cylinder. They looked fine. Pulled off all the rocker brackets and #3 bracket was broken, but a fresh break without dirt in the crack so I may have cracked it by mistake. But that was not the cylinder that had the issue it's #1 with 0 yes ZERO compression dry and wet tested for compression 0 both ways! So then I pulled the push rods out, they looked fine. Unbolted the head and was expecting a LARGE hole in my piston but to my surprise no damage at all just a light amount of carbon and unburned stuff. Next I removed the head gasket (It was not an original metal type) it it appeared to be in good shape but I can't tell if it was blown! One small water jacket hole had a piece of old RTV sealer that must have got trapped one time. Now I check the head, no visible damage to the head and the valves appeared to be seated without damage. Springs are ok. The head had one oil port clogged with carbon at the top right outside corner near #1 cylinder. Not sure if this was the issue, I doubt it since I have 0 compression!!!! Now what? I have no clue what to look for now! The #1 cylinder is at top dead center so I can't see down the cylinder wall. This is a real weird one!! The car ran good enough to drive around town I am BAFFLED I need some sound advice at this point.

442scotty

How does the #1 piston look in comparison to the others on that bank...same goes for the valves...coloration differences?...any scratches in the cylinder walls ? If you can, post some pics so we can have a look

HurstOlds1775

I have a few pictures that I took after the tear down. They are in order and show the parts that would have affected cylinder #1. Hope this works! They are stored in Hotmail and here is the page to see them:

https://skydrive.live.com/?wa=wsigni...!124&sc=photos

442scotty

Easy enough to see which one wasnt firing. looks like #3 beside it was heading down the same path...I cant see the flip side of the head gasket but it looks like its been leaking in 1 and 3

442scotty

Might be time for an overhaul..if you get lucky you might get away with just a re-ring, hone, bearings, cam yada yada..The old girl could use a freshen up after 40 yrs...I think Thats about where Im gonna be with my 50K mile engine...Preventive maint. Especially with head gaskets after all this time.

TripDeuces

http://www.classictruckshop.com/club...ts/vac/uum.htm

A vacuum gauge and the above chart might help you nail it down. It's obvious you have a leak but is it the rings or a valve. The fact that you tried oil and nothing changed points to a valve. Unless of course like you said the piston is holed but I think that's unlikely.

MDchanic

Unfortunately, in your pictures, you've got some strobe flare right on the sealing surfaces of both the heads and the block, so it's impossible to know whether there are any signs of leakage there.
As for the gasket, it does look a bit hairy to me, and I'd go for that as the cause.
The question must be asked, since that's an aftermarket gasket, whether there was a head gasket problem in the past, perhaps caused by slight head warpage (not very common with cast iron heads), which was not fixed, and which caused the current problem as well as the original problem.
Is the other side an aftermarket gasket or an original one (plain steel shim- you should be able to tell without removing the head)?

You pistons and cylinders look great.

I'd pull the valves on that #1 cylinder, just to be sure they're fine, and install new valve guide seals on that head, just because it's easy with the head off, then bolt 'er on and see what happens. I would not mess with anything else, unless you've been looking for an excuse to rebuild it. If it runs great on seven cylinders, you'll be happy as a pig in poop with how it runs on eight! (... and they WILL run well on seven - I had a buddy years ago who drove a '67 Newport from NY to Cali towing a heavy trailer, and noticed when he got there that one spark plug wire had been off the whole time. Said he never noticed a problem, but it did run better with that extra cylinder .)

- Eric

442scotty

And while you have the one head off you may as well take the other off to give it a fresh head gasket...and valve seals...

Nilsson

Pour liquid such as kerosene for example in the intake and exhaust ports. Look for leakage at the valves.

gearheads78

Look at the cam and lifters on that cly. I bet you have a intake valve not opening.

edit: I went back and re -read the first post so that can't be it either.

MDchanic

I like that idea as well. Definitely rotate through and make sure your pushrods are going up (or rockers are going down) the same on that cylinder as on the rest of them. If you're lucky, it would just be a bad lifter (well it would just be a clogged lifter, that you could take apart and clean).

I should have thought of that .

- Eric

HurstOlds1775

Tonite I will put the distributer back in and rotate the crank so #1 is at intake stroke and check the wall of that cylinder. I wil also do the valve check with Kerosene in both exit ports of the head to see if there is leak by. If so I will remove both valves from that head and check them out. I hope it's just the head!! If not I have no clue what it could be! (MDchanic) Would you like me to take a few more pictures just to clear things up to see if the gasket blew out?) All of your thoughts from everyone have been very helpful!! That's why this is such a great site. I was a Chevy guy about 35 years ago then I got educated to Oldsmobile. I thought even back then to have 0 compression you must have a catastrophic problem, but I guess I'm very wrong. I just seems real weird how this so tough to figure out. I would understand if the compression was like 40 or 50 then it would make sense not finding anything obvious, but ZERO is just plain nuts!! That's my 2-cents. I will keep you all posted and please keep the ideas coming so it will save me time and aggravation!

gearheads78

I went through the same senerio last year but this is not your problem since you said the rockers are all moving.

I was working on a 400 Pontiac with 155-165 on 7 clys and 0 on the other. I was pulling my hair out even after taking the head off. I then finally saw the intake lobe was gone and the lifter was 1/4" shorter than it started out as and a nice concave pattern ground out of the face of it.

HurstOlds1775

Here is the latest update. Used denatured alcohol and filled the valve tub where they seat and it did not leak out thru the seats. So I tipped heads on the side and fulled the intake chamber with the alcohol, no leak out. Flipped over and did the same to the exhaust chamber, no leak out. Wrenched the crank pulley so #1 was at bottom dead center and there a no scores at all in the cylinder walls, same as all the other ones on that bank. I am perplexed at this point! I checked the head gasket again and does appear to have a dark area exiting the cylinder and going to a coolant chamber but I don't know what I'm looking for! I still feel it it the head gasket at this point. Would the gasket give ZERO compression? Here are the photos. Let know what you think now!!!!

https://skydrive.live.com/servererro...2A1B58B329!137

HurstOlds1775

(joesw31) That sounds like a very easy test for the broken rings and I wish I knew that before I ripped into this. Any other ideas before I just bolt this back together and sell it since I'm getting sick of it! This is real neat car that I want to enjoy this year!

HurstOlds1775

joesw31, Do you think my piston would break like that and not score the cylinder wall at all? If that's it, I'm one LUCKY S.O.B. When I filled the cylinder with air when the engine was together it came out as fast as it went in! At 125 PSI. That had to be a big leak-by and rings would make sense but..........no damage or debris? I will go out and start with the cam shaft. When I turned it over before I tore it down both valves springs and valves compressed about 3/4 of an inch, do you still think it could be cam or am I wasting my time and just dig into the lower end? Thanx for all your advice!!

HurstOlds1775

Ok lets say that's the problem. Will this be a problem in the future with the other cylinders, like will they break too? Can I still get a stock 455 high comp piston from GM and If not then where do I go or do I have to replace them all? Is there anyway to check without ripping down the pan. I'm thinking a feeler gauge around the piston to see if there is damage. It has to be the top ring groove right? Since it had no compression, if it is lower on the piston then the top ring would have sealed with the oil during compression test. Or am I way out of whack here!! I just didn't want to break down the bottom end cause then I feel I should just do the whole thing over and that's a BIG money issue right now. What would you do if it was your car and it had low miles 68,000? Keep me focused on the issue cause I'm loosing my mind with this!

Lady72nRob71

How about take a PVC pipe cap big enough to cover the cylinder, and a small sheet of rubber (available as gasket material int he plumbing section), drill a small hole in the center of BOTH just big enough for your air gun nozzle, hold the cap over the cyl with rubber in the middle, blow air in and see where the air goes. IF it does not try to exit hard around the cap, then the it is something with the rings.

Strange idea I know, but I would have a hard time pulling the motor and pistons just to check.

BTW, you said you checked compression with oil iin the cylinder. How much oil? Was there any left in there when you pulled the head? Fill'er up and see how fast it drains?

You seem to have my kind of luck. A seemingly easy probllem to see is invisible. At this point, my luck would have had the issue beieg a defective compression gauge.............

I wish you luck!

MDchanic

Sometimes the piston and rings break and look like shattered glass along the side when you get them out. You'd be amazed.

I agree that if you saw good movement of both rockers before, then the cam or lifter are not likely culprits, but it's not hard to pull the lifters and check all that, so you might as well while it's apart.
The valves sound good, and the head gasket looked iffy, but not terrible, so that's not conclusive at all.
That definitely leaves the piston as a possible cause, so, sorry to say, I'd jack up the motor a bit in the front, drop the pan, pull the #1 rod cap, and take out that piston.
Is there much of a ridge at the top of that cylinder? If so, you'll probably need to reduce it to get the piston out, but other than that, once the oil pan is out, it's a 1-2-3 job to pull the piston out for a look. Be careful not to touch the bearing surface with the rod bolts as you push out the piston.
Once it's out, you'll know the whole story.

- Eric

442scotty

From the pics the head gasket for sure is done and looks like it could have crossed over to the next cylinder a bit. But you probaby have ring issues I would think..If your compression was up you should have seen lots of bubbles in the rad...the rings could be stuck in the land from all the gunk. Like joesw31 says...pop it out and cross your fingers...

Money is always tough these days...If you have the time and money you could probably freshen up the engine as I mentioned earlier but at least do the one piston and change both head gaskets.

MDchanic

Not to be contradictory, but my advice would be to just change the one head gasket.

If the car is a driver, then my philosophy would be to avoid looking for trouble. The last thing you want is to be pulling the head to change a non-leaking head gasket "just because it's a good idea" and bust off an exhaust manifold bolt or two, thus creating a new problem, and turning a quick, easy job into a slow, ugly one...

...just my 2¢.

- Eric

rustyroger

Going back to the beginning, if you get zero compression it points to a valve sticking open, even with broken rings a wet test would yield SOME compression, maybe only 20 or so but you should get something. You have taken the head off so a holed piston can be rulled out - you would have blowby symptoms anyway.
You have the head off now so pull the valves and check for a bent stem, I suspect you may have a lifter pumping up and hanging the valve out.
Good luck!.
Roger.

442scotty

You now have enough advice to make your head swim

HurstOlds1775

I like the idea of getting air in the cylinder to check for leak by with the piston. I think I can make something up that may work. When I tested for compression the first time I used a little bit of 30 weight in the cylinder, zero, then I tried 80 weight and used a tube to get it on top of the piston, still ZERO. I ran the car after that so I don't know if it leaked by or bunt out. What about the denautred alcohol test in the cylinder now, to see if it leaks down. Would that indicate I should tear it down? Another quick question, can the valve be bent or hung up and not be leaking off the engine? I did notice that both lifters were cleaner at the push rod area (top) than the rest and one push rod was full of oil that did not drain right out, I had to blow it out with my mouth to clear it. I just thought it was gunked up from the blow-by. And I did hear a slight lifter tap before this started but it was very slight. Also the head bolt at the outside top of the bad cylinder did not make that braking sound when I removed it like all the others. The car only smoked at high RPMs under a load, other than that it ran better than you would think with this problem!!! I forgot to mention that the car sat for 3 years before this and was started a few times, but not driven. Very low miles on the car so taking down the other head should be easy. Nothing is rusted on the car which makes working on it very easy.
Oh yea, there are ridges in all four cylinders at the top that my finger nail rides over. Will honing reduce this without taking doen the cylinder wall in that area?

1) So my next steps are to do a leak by with the Alcohol.
2) Then a Compression test with the PVC cap.
3) If that checks out I will pull both valves in the head.
4) I will also check the lifters on that cylinder, but I don't know what I'm looking for with them! I have heard of a stuck ball inside that can keep the valve open just a little bit. Is this true?

Sorry for the VERY LONG posts but this has been a weird repair and I have learned ALOT from all of you! I'm sure your all wondering what the hell it is like me!

HurstOlds1775

442scotty I do have alot of advice but it's all very helpful! And the biggest thing of all!! I don't feel like I'm in this alone, everyone is helping me and that makes it easier for me!!!

Lady72nRob71

Not sure about filling the cyl with alky... Tranny fluid would mix well with the oil and can be easily drained out with it. It is very thin, too.
I thought I was the only one getting baffling issues like this!

HurstOlds1775

Tranny fluid it is! Will it leak by with a broken piston?

HurstOlds1775

I pressed a plastic container with an elastic around it to seal the cylinder in the cylinder and applied 70 PSI. It kept poping out and leaking around the sides of the container at the top of the cylinder. So I think that sealed up Ok and that would tell me that the rings are sealing up. Then I filled the cylinder to the top of the lower lip with tranny fluid. After a 1/2 hour it leaked by just over an 1/8 of an inch lower from the top. Is that good or bad? Should I still pull the piston? Hate to be a nag but I just don't want to ruin the bearings while pulling the piston out, I know that can be tricky with the engine in the car. My next step is up to you all, so let me have it!

compedgemarine

you could remove the rings completely and you would have at least some compression so I dont think the bottom end is the issue. as was suggested it sounds like a valve stuck open. if you have the heads off and the valves are closing and sealing then it is more likely a lifter that is either stuck and is now acting like a solid lifter or is sticking in the bore and not letting the valve close. I would pull the lifters one at a time and check the bore and also pull the clip out and take the lifter apart to make sure it is able to compress.

Lady72nRob71

X2 - need to have a comparison...
So air did not pass through the rings like it was escaping before - this is getting interesting.

rustyroger

If the engine has been sitting for 3 years I think you almost certainly have a valvetrain problem, maybe a sticking valve, or a lifter pumping up and/or sticking.
If you have a wear ridge in the bores you won't fix anything by honing the bores, the bores are worn and no longer perfectly round, more than around .005" and it needs a rebore.
Sorry to be a wet blanket but you will never get a worn engine running great.
Roger.

HurstOlds1775

This is today's update: This FINAL test will cost me about $28.00 and a hour and a half of labor. I have decided to bolt the head back on with a new ($28.00) head gasket, just the head. I will then do another compression test since I pulled both valves today and they are in nice shape, seats are too. This way if I have good compression then I don't have to take down the lower end. If I don't get any compression then I know my piston is junk and if that's the case then I should just do the whole lower end over. If compression is good I will take it from there to find my problem! All of you guided me in the right direction with this headache, Thanx!

MDchanic

When you do, get a rough measurement of the rocker arm movement in comparison to the adjacent cylinder, to be sure that the valves are opening and closing all the way.

I'd also pull those two lifters, take them apart, and clean them while it's all opened up, just to be sure.

- Eric

HurstOlds1775

OK all here it is. I bolted the head gasket on and inserted all the push rods and bolted down rockers and began a compression test on the other cylinders first!! Results are..................these are quick tests: #2=130 #4=120 #6=140 #8=130 other side #7=125 #5=115/125 with little oil #3=135 and the big problem cylinder is..............ZERO wet and dry!!!! Also zero with valve train disconnected! So all of you that said "The piston is broken, shot, cracked, etc" were RIGHT! WAS WRONG! Now my direction is what? I have to think about this long and hard. Do I rebuild or just fix the problem and pray for years of a 1,000 miles a year for a while.

So I am asking, if any member out there reading this post has a 1969 or 1968 455 with high compression engine if they would unload it to a fellow member for a reasonable price? It is going into a neat old car with very little restoration other than a paint job and some minor paint to the engine compartment.

Looking forward to your new posts on this and what direction I should go in.

What sucks the most is, it ran fine!!! I should have kept my dirty paws of it!!

MDchanic

Naaaah. It ran fine FOR NOW, but something BAD was going to happen fairly soon, like a hole in that piston, or deep, unfixable scoring to that cylinder.

Look at all the work you did already. At this point, I'd say, drop the pan, pull the piston, see what you've got, and fix it if it's fixable. It's not THAT much, compared to what you've already done, and you've done a lot of the work already.

But first, sit down, have a beer, let it sit for a few days or a week, and don't think about it.

- Eric

HurstOlds1775

Eric,
You my friend are a very wise man! Having a beer as I post this!! I think I am heading in that direction but I would hate to do it again next YEAR!