Piston Rings?

[93LaserRSBham]

I had a compression test done, and I have 0 in #4 cylinder. When I changed spark plugs, there was about a shot glass or less worth of oil in the plug well. My exhaust smells gassy, but no smoke at all. The car runs ok I guess, but the engine vibrates at idle (shaking back and forth). My gas mileage was great, around 400 miles to a tank (or about 25 mpg) and now I'm getting about 17-18 mpg. The car does well over 3,000 RPM, but anything under that it lugs the engine. It's been running this way for a while now, maybe over 6 months, but it's not getting any worse. Someone (a mechanic who seems kind of shady) told me it was my piston ring(s) and that I shouldn't even drive it, that I should have it towed to his "buddy's" garage. He also told me this before when he claimed that I had a head gasket leak and he would be "scared" to drive it any further and that was about 30,000 miles ago, . Any other opinions, or is he right this time?

 

[oldman]

Who did the test and under what conditions? Do the compression test again and make sure it was done right. http://www.geocities.com/dsmgrrrl/FAQs/compression.htm Do it dry then wet and post back both sets of numbers.

 

[huafist]

If it's not burning anything but you still have 0 compression in #4 after both wet & dry tests, you may have a bent valve.

 

[93LaserRSBham]

So...if I have a bent valve, is there a possibility that my rings are ok? And if the rings are ok, is a bent valve something that's equally as bad as far as cost of repair is concerned?Thanks for the advice guys, I don't know how he did my compression test because I was at work at the time. The only reason I took it to this mechanic is because his shop is directly across the street from my work, so it was convenient for me to leave it with him for a few hours. I'll do the test myself this time around, and I'll be sure to post back the results. Thanks again!

 

[oldman]

Bent valves = pullin head
bad rings = pulling block

 

[huafist]

So...if I have a bent valve, is there a possibility that my rings are ok? And if the rings are ok, is a bent valve something that's equally as bad as far as cost of repair is concerned?Thanks for the advice guys, I don't know how he did my compression test because I was at work at the time. The only reason I took it to this mechanic is because his shop is directly across the street from my work, so it was convenient for me to leave it with him for a few hours. I'll do the test myself this time around, and I'll be sure to post back the results. Thanks again!

I doubt seriously there's anything wrong with your rings. I'm betting a bent valve or two.

 

[93LaserRSBham]

Well, the previous owner was a good friend of mine and he did have his timing belt snap around 70-80k miles, I can't remember when exactly. Anyway, he did bend half his valves and paid out the ass for the repairs. I think the car could still be suffering from that now that you guys say it might be bent valves. The car has 160k on it now, but I changed my timing belt a while back, maybe a year or two ago, and the mechanic there told me he "fixed" my timing. He said my intake timing was forward a couple of degrees and that my exhaust timing was retarded a little bit too. It might have been the other way around, I can't remember. I think that was about 30,000 miles ago, and the car did run extremely better after he worked on it, so I'll take it to him again.

 

[93LaserRSBham]

Well, I'm planning on doing the compression test this weekend when I finally get some off time, but I talked to a friend of mine who really knows cars, and he said it might be a valve guide, any thoughts?

 

[halligoo]

I think that it would be an excellent idea to park it until you get the '0' compression issue resolved. It isn't worth the risk of causing more damage. The Valve cover gasket is probably leaking causing the oil in the plug well. Probably not related to the compression issue.

 

[gurrmanator]

when you bend a valve it usually takes the guide with it.I think your are going to end up pulling the head...its not tough to do it yourself and way cheaper...get a manual and read up

 

[93LaserRSBham]

Thanks for the advice, I'm just starting to get my hands dirty with this car, any and all help is appreciated! I guess I've got some homework to do....

 

[luv2rallye]

Does your oil look discolored? Bad rings will do that. It sounds more like either a bent valve or one that is not seating properly (not unusual after 80k) - need valve job. Remove head and take it to a reputable engine machine shop - they will fix it right up for ya. You'll need a new head gasket and probably intake and exhaust ones too. You can get all gaskets in a kit from the shop. Give yourself lots of time and make sure you have a manual and torque the head bolts properly.

 

[93LaserRSBham]

The oil's not discolored really, but it gets kind of dark after a while if that's what you mean. I've been putting Mobil 1 Synthetic in it for the last couple of years. Isn't it normal for the oil to get a little darker after a lenght of time?

 

[luv2rallye]

Yes. By discolored I meant looking like mixed with fuel or foaming, etc.

 

[95gstHRCsuper20]

Redo the compession check, make sure all plugs are out the whole time and unplug the ignition modules. If you have an adjustable CAS with a plug disconnect it. This will keep the fuel from entering to decrease variables. If your #4 is still showing low or 0 add about a teaspoon of oil directly in the plug hole. If the compreesion comes up you will have a ring situation but I believe you will have a bent valve a bad hydraulic lifter. If that is the case and you do send it to a reputable machine shop take advantage of the fact that you have the head off. Have the shop port and polish the head intake and exhaust. If you have a little more money the same shop should be able to properly turn your cams to give longer duration. The machine shop should know what will be more benificial for your driving habits. If you need specs look at aftermarket cam specs bullfrog cams are good quality and any website should list the durations. If you want to experience changing valves yourself, remember to check all spring free lengths lap and seat ald and new valves AND LUBE LUBE LUBE TORQUE SPECS ARE VERY IMPORTANT I can get just about any specs via ALLDATA most auto shops use either this or mitchell on demand.
Victor J. Bozzelle

 

[BigBoizGS]

Well, the previous owner was a good friend of mine and he did have his timing belt snap around 70-80k miles, I can't remember when exactly. Anyway, he did bend half his valves and paid out the ass for the repairs. I think the car could still be suffering from that now that you guys say it might be bent valves. The car has 160k on it now, but I changed my timing belt a while back, maybe a year or two ago, and the mechanic there told me he "fixed" my timing. He said my intake timing was forward a couple of degrees and that my exhaust timing was retarded a little bit too. It might have been the other way around, I can't remember. I think that was about 30,000 miles ago, and the car did run extremely better after he worked on it, so I'll take it to him again.

How mush was it to replace your timing belt mine is jumping and causing no compression so im needing to get it and the tensinor replaced if you can tell me howm uch it would that would help alot thanks!

 

[93LaserRSBham]

Well, the last time I got the timing belt replaced was when I had my mechanic put a new water pump on, and I think it was around $400...I just went ahead and put a new belt on while he had the old one off while doing the water pump since you have to take it off anyway.

 

[BigBoizGS]

Well, the last time I got the timing belt replaced was when I had my mechanic put a new water pump on, and I think it was around $400...I just went ahead and put a new belt on while he had the old one off while doing the water pump since you have to take it off anyway.

Ok thanks, so it will hopefulyl be even less, my DMS goes int othe shop tommorw morning yeaaa! it turns over but wont start stupid thing and the timing is jumped so yea ill update you when the guy tells me whats wrong and how much it will be to fix thanks!

 

[BUCK]

I did Rings, Front Case Seals & Water Pump, Rod & Crank Bearings & BSE with Block in car on 4 Jack Stands - I wouldn't pull Motor if I had to do it again.