Re: ZJ Engine overhaul questions
 

DougW wrote:
> J. Clarke wrote:
>> DougW wrote:
>>> J. Clarke wrote:
>>>> My 97 ZJ needs an engine overhaul--has a cracked ring (or worse).
>>>> I'm debating my options. Pulling the engine, overhauling it
>>>> myself,
>>>> and putting it back is out--with the engine out of the Jeep I
>>>> wouldn't have any way to get the block to the machine shop. So I'm
>>>> debating whether to
>>> what makes you think it has a cracked ring? Just wondering because
>>> the valve springs on that year had some failure issues.
>> Symptoms are (1) one and only one plug is getting oil-fouled
>> regularly, (2) low compression on that cylinder, (3) engine is using a
>> lot of oil, (4) blows small amount of blue smoke.
>
> To me that sounds like a worn valve guide allowing oil to get sucked down
> in from above.
>
> Have you tried a squirt(teaspoon) of 30W oil into the low one?
> If the compression goes up, it's rings. If the compression
> stayes the same, it's valve or possibly head gasket. But if
> it was the gasket you would have other symptoms.
>
> Also if you have a vac gauge, see if it matches any of the problems
> shown here: http://www.iwemalpg.com/Vacuum_gauge.htm
>
>
BUT is he has a busted oil ring but the compression ring is OK that test
won't show it... although if it's lost compression because of a busted
compression ring scoring the cylinder the test would show that.

How about a cylinder leak down test? Then you can hear if the air is
escaping into the crankcase or into the intake or exhaust.

Jeff DeWitt

Re: Re: ZJ Engine overhaul questions
 

On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt <JeffDeWitt@nc.rr.com>
wrote:

>BUT is he has a busted oil ring but the compression ring is OK that test
>won't show it... although if it's lost compression because of a busted
>compression ring scoring the cylinder the test would show that.
>
>How about a cylinder leak down test? Then you can hear if the air is
>escaping into the crankcase or into the intake or exhaust.


Actually it would show if you read data right. if oil ring is busted
(very unlikely) there would not be much diffence in wet/dry readings.
Something else to consider here is a stuck ring. I have seen this in a
lot of cars especailly some GM models. Extended, infrequent oil
changes or wrong oil grade is the main cause of stuck ring issues. If
engine has not been serviced often I would consider this and if so
this is curable without a teardown.
-----------------
TheSnoMan.com

Re: Re: ZJ Engine overhaul questions
 

On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt <JeffDeWitt@nc.rr.com>
wrote:

>BUT is he has a busted oil ring but the compression ring is OK that test
>won't show it... although if it's lost compression because of a busted
>compression ring scoring the cylinder the test would show that.
>
>How about a cylinder leak down test? Then you can hear if the air is
>escaping into the crankcase or into the intake or exhaust.


Actually it would show if you read data right. if oil ring is busted
(very unlikely) there would not be much diffence in wet/dry readings.
Something else to consider here is a stuck ring. I have seen this in a
lot of cars especailly some GM models. Extended, infrequent oil
changes or wrong oil grade is the main cause of stuck ring issues. If
engine has not been serviced often I would consider this and if so
this is curable without a teardown.
-----------------
TheSnoMan.com

Re: Re: ZJ Engine overhaul questions
 

On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt <JeffDeWitt@nc.rr.com>
wrote:

>BUT is he has a busted oil ring but the compression ring is OK that test
>won't show it... although if it's lost compression because of a busted
>compression ring scoring the cylinder the test would show that.
>
>How about a cylinder leak down test? Then you can hear if the air is
>escaping into the crankcase or into the intake or exhaust.


Actually it would show if you read data right. if oil ring is busted
(very unlikely) there would not be much diffence in wet/dry readings.
Something else to consider here is a stuck ring. I have seen this in a
lot of cars especailly some GM models. Extended, infrequent oil
changes or wrong oil grade is the main cause of stuck ring issues. If
engine has not been serviced often I would consider this and if so
this is curable without a teardown.
-----------------
TheSnoMan.com

Re: Re: ZJ Engine overhaul questions
 

On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt <JeffDeWitt@nc.rr.com>
wrote:

>BUT is he has a busted oil ring but the compression ring is OK that test
>won't show it... although if it's lost compression because of a busted
>compression ring scoring the cylinder the test would show that.
>
>How about a cylinder leak down test? Then you can hear if the air is
>escaping into the crankcase or into the intake or exhaust.


Actually it would show if you read data right. if oil ring is busted
(very unlikely) there would not be much diffence in wet/dry readings.
Something else to consider here is a stuck ring. I have seen this in a
lot of cars especailly some GM models. Extended, infrequent oil
changes or wrong oil grade is the main cause of stuck ring issues. If
engine has not been serviced often I would consider this and if so
this is curable without a teardown.
-----------------
TheSnoMan.com

Re: Re: ZJ Engine overhaul questions
 

SnoMan wrote:
> On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt
> <JeffDeWitt@nc.rr.com>
> wrote:
>
>> BUT is he has a busted oil ring but the compression ring is OK that
>> test won't show it... although if it's lost compression because of
>> a
>> busted compression ring scoring the cylinder the test would show
>> that.
>>
>> How about a cylinder leak down test? Then you can hear if the air
>> is
>> escaping into the crankcase or into the intake or exhaust.
>
>
> Actually it would show if you read data right. if oil ring is busted
> (very unlikely) there would not be much diffence in wet/dry
> readings.
> Something else to consider here is a stuck ring. I have seen this in
> a
> lot of cars especailly some GM models. Extended, infrequent oil
> changes or wrong oil grade is the main cause of stuck ring issues.
> If
> engine has not been serviced often I would consider this and if so
> this is curable without a teardown.

I am curious as to how one would cure a stuck ring without a teardown.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Re: Re: ZJ Engine overhaul questions
 

SnoMan wrote:
> On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt
> <JeffDeWitt@nc.rr.com>
> wrote:
>
>> BUT is he has a busted oil ring but the compression ring is OK that
>> test won't show it... although if it's lost compression because of
>> a
>> busted compression ring scoring the cylinder the test would show
>> that.
>>
>> How about a cylinder leak down test? Then you can hear if the air
>> is
>> escaping into the crankcase or into the intake or exhaust.
>
>
> Actually it would show if you read data right. if oil ring is busted
> (very unlikely) there would not be much diffence in wet/dry
> readings.
> Something else to consider here is a stuck ring. I have seen this in
> a
> lot of cars especailly some GM models. Extended, infrequent oil
> changes or wrong oil grade is the main cause of stuck ring issues.
> If
> engine has not been serviced often I would consider this and if so
> this is curable without a teardown.

I am curious as to how one would cure a stuck ring without a teardown.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Re: Re: ZJ Engine overhaul questions
 

SnoMan wrote:
> On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt
> <JeffDeWitt@nc.rr.com>
> wrote:
>
>> BUT is he has a busted oil ring but the compression ring is OK that
>> test won't show it... although if it's lost compression because of
>> a
>> busted compression ring scoring the cylinder the test would show
>> that.
>>
>> How about a cylinder leak down test? Then you can hear if the air
>> is
>> escaping into the crankcase or into the intake or exhaust.
>
>
> Actually it would show if you read data right. if oil ring is busted
> (very unlikely) there would not be much diffence in wet/dry
> readings.
> Something else to consider here is a stuck ring. I have seen this in
> a
> lot of cars especailly some GM models. Extended, infrequent oil
> changes or wrong oil grade is the main cause of stuck ring issues.
> If
> engine has not been serviced often I would consider this and if so
> this is curable without a teardown.

I am curious as to how one would cure a stuck ring without a teardown.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Re: Re: ZJ Engine overhaul questions
 

SnoMan wrote:
> On Sun, 07 Oct 2007 19:33:30 -0400, Jeff DeWitt
> <JeffDeWitt@nc.rr.com>
> wrote:
>
>> BUT is he has a busted oil ring but the compression ring is OK that
>> test won't show it... although if it's lost compression because of
>> a
>> busted compression ring scoring the cylinder the test would show
>> that.
>>
>> How about a cylinder leak down test? Then you can hear if the air
>> is
>> escaping into the crankcase or into the intake or exhaust.
>
>
> Actually it would show if you read data right. if oil ring is busted
> (very unlikely) there would not be much diffence in wet/dry
> readings.
> Something else to consider here is a stuck ring. I have seen this in
> a
> lot of cars especailly some GM models. Extended, infrequent oil
> changes or wrong oil grade is the main cause of stuck ring issues.
> If
> engine has not been serviced often I would consider this and if so
> this is curable without a teardown.

I am curious as to how one would cure a stuck ring without a teardown.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Re: ZJ Engine overhaul questions
 

J. Clarke wrote:

>
> I am curious as to how one would cure a stuck ring without a teardown.
>

You can remove the spark plug and pour a solvent into the cylinder and
let is soak for a few hours or overnight, then pour some more, wait a
bit and run it. I have had good luck using carb cleaner, penetrating
oil and have heard a soak in kerosene will also loosen it.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
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