Hey Guys,
Just wanted to say thanks again. I replaced the broken valve spring and
tested compression on the cylinder...it was around 150 psi...buttoned
everything back up and she runs like a champ again. You guys saved me
from the expense of a timing chain, sprockets and gaskets.
BTW, out of curiosity, what is the average life of a timing chain on the
4 cylinder 2.5L Daks? It seems to me it should have lasted more than
100,000 miles (thats when it was changed out--supposedly had gone bad).
I guess I could open it up and look at it...but how exactly would I
tell wear on it? Looseness? Oh well, have a good weekend!
Wilbur
Wilbur wrote:
>
> That would be good. :) It would definitely make the job easier. I had
> to order the valve springs...none of the local parts places or the dodge
> dealership had any in stock...So the Dodge dealership is ordering some
> from Dallas, I think.
>
> FYI, when I started taking things apart, I noticed that the CCV vacuum
> tube was broken...so I had the dealership order one of those too...they
> had to order that little item from Detroit. :) I wonder why the 2.5L
> have a CCV (Crank Case Ventilation) vacuum tube instead of a PCV valve
> like the larger engines?
>
> Oh well....supposedly all the parts will be in by next friday so I will
> proceed at that time to replace the valve spring...Thanks for all the
> help guys--Cross your fingers and say a prayer for me. Hopefully this
> will bring my baby back to working order for a bit. You guys are really
> a great bunch of people. :) I'll let you know how it goes. Have a
> great weekend guys!
>
> Wilbur
>
>
>
>
>
> Aaron Wyse wrote:
>
>> at TDC.. maybe 3/4 inch max.. just my ballpark guess.. The cyl head
>> pockets
>> can't be that big.
>> Aaron
>>
>> ----- Original Message ----- From: "Wilbur" <bwgreen@ocean.otr.usm.edu>
>> To: <dakota-truck-moderator@bent.twistedbits.net>
>> Sent: Thursday, January 15, 2004 10:59 PM
>> Subject: Re: DML: replacing timing chain on 1998 dakota 2.5 liter
>>
>>
>>
>>> Yeah I think I will start with replacing the one bad spring and go from
>>> there...I wonder...at TDC, how far would the valve "fall" in if I were
>>> to replace the spring and I was unable to keep hold of the valve stem?
>>> Would it fall far enough in that I could not reach it or would enough of
>>> the valve stem be sticking up to pull it back up? just curious.
>>>
>>> Wilbur
>>>
>>>
>>>
>>> Aaron Wyse wrote:
>>>
>>>> another way to hold the valve up is to fill the cylinder with a rope
>>>> (at
>>>> BDC) and then then give the crank a little bump to compress it a
>>>> little.
>>>>
>>>> Personally.. I would just replace the one bad spring.. then do another
>>>> compression test. If all is well. Drive it another 50K miles or so
>>
>>
>> before
>>
>>>> I worry about anything else. Since a valve spring should not have
>>
>>
>> broken in
>>
>>>> the first place, assume it as more of a fluke break than an actual high
>>>> mileage problem. Make sure you do a couple of oil change fairlu close
>>>> together.. just in case any particles of spring are circulating around
>>
>>
>> in
>>
>>>> there.
>>>> Otherwise.. The valve may have actually damaged something that will
>>
>>
>> require
>>
>>>> more work. And you'll need to go in deeper.
>>>> Also.. glad you found the problem
>>>> Just my opinions.
>>>> Aaron Wyse
>>>>
>>>>
>>>> ----- Original Message ----- From: "Wilbur" <bwgreen@ocean.otr.usm.edu>
>>>> To: <dakota-truck-moderator@bent.twistedbits.net>
>>>> Sent: Thursday, January 15, 2004 4:00 PM
>>>> Subject: Re: DML: replacing timing chain on 1998 dakota 2.5 liter
>>>>
>>>>
>>>>
>>>>
>>>>> You bet I will. :) Ok currently....I put cyl #1 to TDC and injected
>>>>> air into sparkplug opening....heard air hissing in valve cover...So
>>>>> removed valve cover, and wahlah, i see the first valve at the front of
>>>>> the engine (facing the fan and radiator) has a busted spring. I am
>>>>> not
>>>>> sure if that one is the intake or exhaust valve spring, just that
>>>>> it is
>>>>> the first one in line. The valve has not dropped...it is still
>>>>> attached. The valve still could have "kissed" the piston, so to
>>>>> speak.
>>>>> So sounds like i need to replace that spring at the very least...and I
>>>>> suppose I should replace the other one of the pair too? Should I
>>>>> replace all the valve springs and and locks and retainers and valve
>>>>> stem
>>>>> oil seals for all 4 cylinders or just for cyl #1?
>>>>>
>>>>> The push rods looked okay from cyl #1, not bent or anything and I have
>>>>> the rockers, bridge and pivot assembly and bolts (also looked fine)
>>>>> sitting in a box in the correct order to put back on.
>>>>>
>>>>> As for replacing the valve springs...from what i can see online, some
>>>>> peeps recommend using air pressure via the spark plug hole to keep the
>>>>> valve seated while taking off the spring....I don't have an air
>>>>> compressor at all to maintain the recommended pressure (90psi) to keep
>>>>> the valve seated. Any other recommendations to keep the valve seated
>>>>> while I remove the spring? Could I tie some string to the valve stem
>>>>> after I have it compressed to keep it from falling into the cylinder?
>>>>> Oh and do the valve compressors you can get at autozone and O'reillys
>>>>> work for this kind of job? Thanks.
>>>>>
>>>>> Wilbur
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Josh Battles wrote:
>>>>>
>>>>>
>>>>>> ""Rick Barnes"" <barnesrv@comcast.net> wrote in message
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Josh,
>>>>>>>
>>>>>>> You blew a ring for that very reason..once you did the great valve
>>
>>
>> job,
>>
>>>>>> you
>>>>>>
>>>>>>
>>>>>>
>>>>>>> increased the compression in the cylinder and the weakened rings
>>>>>>> could
>>>>
>>>>
>>>> not
>>>>
>>>>
>>>>>>> hold the increased compression..viola, broken rings...common, and
>>>>>>> your
>>>>>>> advice is right on, (in my humble opinion). If you do a valve
>>>>>>> job, at
>>>>>>
>>>>>>
>>>>>> least
>>>>>>
>>>>>>
>>>>>>
>>>>>>> replace the rings too.
>>>>>>>
>>>>>>> Rascal
>>>>>>
>>>>>>
>>>>>>
>>>>>> that's what my uncle told me... (ase master certified mechanic) after
>>>>
>>>>
>>>> the
>>>>
>>>>
>>>>>> fact, and while he was helping me replace the rings and smooth out
>>>>>> the
>>>>>> slight cylinder wall scoring. If I was gonna do it now, I'd do it
>>>>>> all
>>>>
>>>>
>>>> at
>>>>
>>>>
>>>>>> once and save myself the extra headache later on.
>>>>>>
>>>>>> learn from our mistakes Wilbur! If you end up having to have valves
>>>>
>>>>
>>>> done,
>>>>
>>>>
>>>>>> do the rings now too so you don't have to do them later.
>>>>>>
>>>>>
>>
>
This archive was generated by hypermail 2b29 : Sun Feb 01 2004 - 16:29:51 EST