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my compression check :(


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so got bored and thought i would do a compression check on my ea82 carb'ed. it wasnt good. first off i suspect my gauge is low but it should be constant. anyways i got 75 on #1, 95 on #3, 70 on #2, and 90 on #4..... so say the gauge reads 20 or 30 lbs low thats still very bad having them vary that much. so i fired her up pulled the oil cap to dump some seafoam in and sure enough gale force winds came out of there. so bad i killed it to put the seafoam in. anyways drove it maybe 5 miles noticed the dead spot and minor mis i was having fade away and when i got home i pulled the oil cap again and it felt like an asmatic mouse coughing in my crank case.. i love seafoam... going to run some in the carb see if i can clean up the carbon on the valves and see what that does.

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First off - the numbers themselves are completely meaningless. They are only useful in relation to each other.

 

70/95 is ~74% so your highest and lowest cylinders are still within about 24% of each other. It would be nice if that were more like 10% to 15% but 24% on an engine that's nearly 30 years old is not that bad.

 

That said I would guess that your testing method is probably not ideal, your gauge could be wildly innacurate, and both of these are contributing to low numbers and probably to the variation in your results. With the right methods and equipment it's entirely possible that the readings will jump up to normal levels and even might be within the magic 10-15% range.

 

So basically - if the engine runs fine and you did the compression check just for kicks..... put down the cheap-o tools and leave this kind of diagnostic work to the pro's.

 

GD

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well mr Generaldisorder first i would like to say you come across as quite the wongleflute. and for somebody of your stature you are setting a bad example for the nice people trying to learn a bit about there super subies. but i do thank you for your response.

 

now on to my car. well it was running poorly. rough idle due to carbon build up around the valves and also a slight mis at operating RPM's probably attributed to the unbalance in the compression. and i know there is other issues that could cause these symptoms but seeing as the symptoms improved i think i was right.

 

now if you put on your spectacles and read my post you'll notice i say its bad they very that much. also my tools are not harbor freight specials they are probably 40 years which as i am sure you know are usually the best. except in my case... ha

 

l75eya: i love the stuff today was a great example of what it would do. i havent used it in fuel much but ive had good success in oil. its made piston slap in my ej25 go away made valve tick quit from the hydraulic 25

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well mr Generaldisorder first i would like to say you come across as quite the wongleflute.

 

I call it like I see it. I do my very best to be honest in everything I do and to save you, me, and the rest of the members of this fine community valuable time. If I come across as a "wongleflute" it's because it was neccesary to sharpen my point.

 

and for somebody of your stature you are setting a bad example for the nice people trying to learn a bit about there super subies. but i do thank you for your response.

 

You are most welcome. As for examples - well you posted your compression results and seemed concerned - you should be happy that I'm giving you hope by telling you to have the test done with properly calibrated tools and someone that is familar with their use and what the results can/cannot used to determine. Again - you're welcome :rolleyes:.

 

now on to my car. well it was running poorly. rough idle due to carbon build up around the valves

 

Objection - calls for speculation.

 

and also a slight mis at operating RPM's probably attributed to the unbalance in the compression.

 

It's "imbalance".... again though - you have what evidence of this? In my experience that is not likely the cause of a misfire at cruise RPM.

 

and i know there is other issues that could cause these symptoms but seeing as the symptoms improved i think i was right.

 

Improved due to what exactly?

 

now if you put on your spectacles and read my post you'll notice i say its bad they very that much. also my tools are not harbor freight specials they are probably 40 years which as i am sure you know are usually the best. except in my case... ha

 

If you can't trust the tool then how do you know they "vary" and besides that how do you know how much variation is "bad"?

 

GD

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being a "wongleflute" is never necessary. there is better ways to get your point across and very few people respond well to rudeness as im sure you have dealt with the issue.

 

i am a professional. i get paid to work on cars. as for my tools i know there proper usage and procedure. i am aware of the gauges low reading. i continued with the test because i knew the car ran to well to have any serious compression problems but i was curious to see how much variation there was between cylinders.

 

carbon build up can cause poor idle. ive seen it before on the identical engine with similar mileage. and yes there is other causes but seafoam in the fuel and oil would lead me to believe it was carbon and/or variation or compression. (seafoam did not pass thru the carb eliminating that as a variable)

 

i could be wrong. but if one cylinder has low compression you wouldnt get as much power from that cylinder cause more of a studder. when under a load it wouldnt be noticeable.

 

im sure you agree leading cause of low compression is rings. that and valve guides. but if the rings became gummed up probably due to poor maintenance throughout its life and just being over 25 years old. seafoam breaks down sludge and sticky oil deposits. wouldnt it be reasonable to assume the rings were gummed up and the seafoam loosened them up.

 

well over all im sure you have experienced similar symptoms with different diagnosis but in MY case they do not apply. all ive said is correct now maybe my logic behind it is wrong but if you look at the facts. my car ran poorly with blow by and a variation in compression after seafoam was used symptoms where greatly reduced or eliminated completely. im sorry but there is no arguing with that.

 

with 19,000 post im sure you have learned a lot and know most your stuff but i would appreciate it if you did not respond to mine. not because you're unintelligent or ill informed but because your rude and i would like to distance myself from you. thanks from your "help" and good luck with your cars.

 

stubies subie: GD seems well informed and it wouldnt surprise me he is usually correct but nobody appreciated being demeaned. im glad we could bring you some entertainment tonight

Edited by kyle234
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stubies subie: GD seems well informed and it wouldnt surprise me he is usually correct but nobody appreciated being demeaned. im glad we could bring you some entertainment tonight

 

GD is one of them guys you would really need to meet, he may come across harsh on here, but in all honesty, he's the type of person that would give you the shirt off his back if he thought it would help you out.

 

he's saved my neck more then once, and like you, I even got mad at him one time and went to his house to let him know, and I walked away humbled, and had to go back later and apoligze for the way I chewed him out.

 

ok, with that said, I had some problems with my car that were a lot like yours, and I seafoamed everything, I soaked the cylinders for close to a week, my compression was all over the place before the seafoam treatment, I filled the cylinders up with it to get a good soaking, I put a can on it in the oil and drove it about 200 miles, and I ran 2 cans of it through the gas tank with a full tank of gas.

 

I went through at least 50 bucks worth of seafoam, and there seemed to be some skeptical people that didn't think it would work .....my car now runs like a fine swiss watch, the compression is now even across all 4 cylinders, and there's no miss or hesatation at any RPM

 

I swear by seafoam ...if you research it out through a search engine like google, you will find those that swear by it, and those that swear at it, and if you look a little closer, you'll find that the ones that are swearing at it are generally the ones that have never tried it.

 

I find that to be the case on a lot of different ideas, the ones that are generally aginst it, have never tried it.

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there is no doubt in my mind GD is very informative. i know i dont have all the answers and i know i could learn plenty from GD but there is some doubt he is as nice as you say he is ;)

 

now maybe gd misunderstood myself or the symptoms i was trying to describe but with my experience and your testimonial it seems as if my diagnosis was for the most part correct.

 

its great stuff maybe there is some long term side-affects but i know i'll sell the car long before i see them. ive noticed that! when i told my buddy i used seafoam he told me my car was going to implode turns out he has never used it. ha

 

correction: i worked as a subaru mechanic at an established and trusted shop as well as a general maintenance shop and spent some time as a mine mechanic. not just some redneck who works on their friends cars haha

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being a "wongleflute" is never necessary. there is better ways to get your point across and very few people respond well to rudeness as im sure you have dealt with the issue.

 

My purpose was not to be rude. My purpose was to call into question your tools and your ability to use them. Think it rude if you wish but to discuss the results of a compression test over the internet without first determining if the test was conducted properly and with the right equipment would be a silly waste of time would it not? I do not know you or your qualifications. Thus I must assume that they are a source of potential error. Whether you like that I do this or not is of little concern to me - be as thin skinned as you like about it. I am only here to solve the problem. I just don't assume that the problem isn't human error. If I did then I wouldn't be the guy people ask to solve their problems :rolleyes:.

 

i am a professional. i get paid to work on cars.

 

Yep. You and everyone else on here :cool:

 

as for my tools i know there proper usage and procedure. i am aware of the gauges low reading. i continued with the test because i knew the car ran to well to have any serious compression problems but i was curious to see how much variation there was between cylinders.

 

You assert that the gauge is inaccurate yet you rely on it's results to determine variation.... that is not compatible logic. If the gauge were off by a percentage then this logic would hold - but you have NO EVIDENCE that the error space of the gauge is linear with respect to the correct readings from a working gauge. Thus you cannot assert that variation percentages will be the same in it's current, damaged state.

 

carbon build up can cause poor idle. ive seen it before on the identical engine with similar mileage. and yes there is other causes but seafoam in the fuel and oil would lead me to believe it was carbon and/or variation or compression. (seafoam did not pass thru the carb eliminating that as a variable)

 

Carbon build-up *where* in the engine will cause poor idle? Generally speaking - carbon build-up will cause a compression problem (if it's around the compression rings or around valve stems causing the valves to stick) - which in turn can cause poor idle. But you have not performed an accurate compression test so you don't really know anything at all.

 

i could be wrong.

 

So could I and everyone else in the world. Non sequitur.

 

but if one cylinder has low compression you wouldnt get as much power from that cylinder cause more of a studder. when under a load it wouldnt be noticeable.

 

Low compression only really shows up at idle. Even on engines with exhaust valves burned all to hell and 150 psi lower compression in a single cylinder you can't even tell when the engine is above 3k RPM.

 

im sure you agree leading cause of low compression is rings. that and valve guides.

 

No I don't agree with you at all. Valve *guides* have nothing whatsoever to do with compression. The valve seat and face are what do the sealing. Bad guides can contribute to oil burning but not generally to compression problems.

 

but if the rings became gummed up probably due to poor maintenance throughout its life and just being over 25 years old. seafoam breaks down sludge and sticky oil deposits. wouldnt it be reasonable to assume the rings were gummed up and the seafoam loosened them up.

 

In my shop it is never reasonable to "assume". You theorize - then you test - and then you KNOW. I will agree that it's a possibility. But I will not assume that it's the only one. Seafoam has worked for me in the past but not usually a single can in the oil as you have done. As Stubies Subie posted above - it can help under certain circumstance and when used WITH science.

 

well over all im sure you have experienced similar symptoms with different diagnosis but in MY case they do not apply. all ive said is correct now maybe my logic behind it is wrong but if you look at the facts. my car ran poorly with blow by and a variation in compression after seafoam was used symptoms where greatly reduced or eliminated completely. im sorry but there is no arguing with that.

 

You have not tested the compression to determine if anything *really* changed. That's not science so YES there is plenty of arguing with it. Which is what I'm doing.

 

with 19,000 post im sure you have learned a lot and know most your stuff but i would appreciate it if you did not respond to mine. not because you're unintelligent or ill informed but because your rude and i would like to distance myself from you. thanks from your "help" and good luck with your cars.

 

You see rude. I see ignorance. Just words. You are here in this forum and so am I. I'm here to learn and so are you - you will have to answer the skeptic's challenges though or no one will take your posts seriously. I have questioned your logic and if it can't stand up to my questions then it's not very good logic and it needed to be questioned didn't it?

 

GD

Edited by GeneralDisorder
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70/95 is ~74% so your highest and lowest cylinders are still within about 24% of each other. It would be nice if that were more like 10% to 15% but 24% on an engine that's nearly 30 years old is not that bad.

 

poor GD, it seems like he always get's scolded for saying it the way he sees it, scold him all you want, the truth is, out of 18,000 plus posts, I'll bet you can't find one where he was wrong ....

 

Does a math error count? :banana:

 

Jacob

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