88 rocco:No compression cyl#4!??

Most likely a valve spring broke or the retainer that holds the valve
to the spring let go. The tapping noise might be the piston hitting
the valve. A friend of mine had this kind of thing happen with his
'68 Datsun. Since the engine was already not 100%, he elected to
replace it with another crated engine he had had in the backyard for
many years, although he did not finish the install, since other stuff
came up. In your case, you can probably fix whatever is broken with
the valve assembly.

On Dec 4, 8:03 pm, one out of many daves
<NOSPAMvwd....DeleteThis@hotmail.comPLEASE> wrote:
> 16V or 8V engine?
>
> Do the spark plugs still look fine?
>
> Might want to do a Leak Down Test to find out where the compression is
> going to. Also might want to pull the valve cover to peak at the
> lifters/followers and camshaft(s).
>
> Not sure here! <
>
>
>
> Regal953 wrote:
> > Maybe Dave has an idea, engine was running fine, all of a sudden I feel
> > a heavy miss after hearing lifter-like tapping noise. Pulled plugs and
> > compression is zero in cyl # 4. What could have caused valves to stick
> > open? Cyls 1,2,3 are fine at 170psig. Timing belt is fine in synch. ???- Hide quoted text -
>
> - Show quoted text -
 >> Stay informed about: 88 rocco:No compression cyl#4!?? 

Chuck wrote:
> Most likely a valve spring broke or the retainer that holds the valve
> to the spring let go. The tapping noise might be the piston hitting
> the valve. A friend of mine had this kind of thing happen with his
> '68 Datsun. Since the engine was already not 100%, he elected to
> replace it with another crated engine he had had in the backyard for
> many years, although he did not finish the install, since other stuff
> came up. In your case, you can probably fix whatever is broken with
> the valve assembly.
>
> On Dec 4, 8:03 pm, one out of many daves
> <NOSPAMvwd... RemoveThis @hotmail.comPLEASE> wrote:
>> 16V or 8V engine?
>>
>> Do the spark plugs still look fine?
>>
>> Might want to do a Leak Down Test to find out where the compression is
>> going to. Also might want to pull the valve cover to peak at the
>> lifters/followers and camshaft(s).
>>
>> Not sure here! <
>>
>>
>>
>> Regal953 wrote:
>>> Maybe Dave has an idea, engine was running fine, all of a sudden I feel
>>> a heavy miss after hearing lifter-like tapping noise. Pulled plugs and
>>> compression is zero in cyl # 4. What could have caused valves to stick
>>> open? Cyls 1,2,3 are fine at 170psig. Timing belt is fine in synch. ???- Hide quoted text -
>> - Show quoted text -
>
Hey thanks a lot guys, I'll go along with Chuck's idea, it makes
complete sense. I saw a 16v 944 got a broken spring and it had a
variable miss, lucky thing the inner valve apring kept it all together
and valves never got mashed, just replaced the spring and that was OK
 >> Stay informed about: 88 rocco:No compression cyl#4!?? 

Regal953 wrote:
> Chuck wrote:
>> Most likely a valve spring broke or the retainer that holds the valve
>> to the spring let go. The tapping noise might be the piston hitting
>> the valve. A friend of mine had this kind of thing happen with his
>> '68 Datsun. Since the engine was already not 100%, he elected to
>> replace it with another crated engine he had had in the backyard for
>> many years, although he did not finish the install, since other stuff
>> came up. In your case, you can probably fix whatever is broken with
>> the valve assembly.
>>
>> On Dec 4, 8:03 pm, one out of many daves
>> <NOSPAMvwd... RemoveThis @hotmail.comPLEASE> wrote:
>>> 16V or 8V engine?
>>>
>>> Do the spark plugs still look fine?
>>>
>>> Might want to do a Leak Down Test to find out where the compression is
>>> going to. Also might want to pull the valve cover to peak at the
>>> lifters/followers and camshaft(s).
>>>
>>> Not sure here! <
>>>
>>>
>>>
>>> Regal953 wrote:
>>>> Maybe Dave has an idea, engine was running fine, all of a sudden I feel
>>>> a heavy miss after hearing lifter-like tapping noise. Pulled plugs and
>>>> compression is zero in cyl # 4. What could have caused valves to stick
>>>> open? Cyls 1,2,3 are fine at 170psig. Timing belt is fine in synch.
>>>> ???- Hide quoted text -
>>> - Show quoted text -
>>
> Hey thanks a lot guys, I'll go along with Chuck's idea, it makes
> complete sense. I saw a 16v 944 got a broken spring and it had a
> variable miss, lucky thing the inner valve apring kept it all together
> and valves never got mashed, just replaced the spring and that was OK
Update: Finally decided to pull that head out, and I gotta say CHUCK
YOU"RE RIGHT!!! upon removing the valve cover, i pushed on the 2 exhaust
lifters and found the rear one went down under slight pressure. Took the
head down and yes sir bent valve enough to see light thru the seat.
Orser my parts and she will be fine again. THANKS CHUCK!!
 >> Stay informed about: 88 rocco:No compression cyl#4!?? 

On Feb 5, 4:28 pm, Regal953 <regal... DeleteThis @comcast.net> wrote:
> Regal953 wrote:
> > Chuck wrote:
> >> Most likely a valve spring broke or the retainer that holds the valve
> >> to the spring let go.  The tapping noise might be the piston hitting
> >> the valve.  A friend of mine had this kind of thing happen with his
> >> '68 Datsun.  Since the engine was already not 100%, he elected to
> >> replace it with another crated engine he had had in the backyard for
> >> many years, although he did not finish the install, since other stuff
> >> came up.  In your case, you can probably fix whatever is broken with
> >> the valve assembly.
>
> >> On Dec 4, 8:03 pm, one out of many daves
> >> <NOSPAMvwd... DeleteThis @hotmail.comPLEASE> wrote:
> >>> 16V or 8V engine?
>
> >>> Do the spark plugs still look fine?
>
> >>> Might want to do a Leak Down Test to find out where the compression is
> >>> going to.  Also might want to pull the valve cover to peak at the
> >>> lifters/followers and camshaft(s).
>
> >>> Not sure here!  <
>
> >>> Regal953 wrote:
> >>>> Maybe Dave has an idea, engine was running fine, all of a sudden I feel
> >>>> a heavy miss after hearing lifter-like tapping noise. Pulled plugs and
> >>>> compression is zero in cyl # 4. What could have caused valves to stick
> >>>> open? Cyls 1,2,3 are fine at 170psig. Timing belt is fine in synch.
> >>>> ???- Hide quoted text -
> >>> - Show quoted text -
>
> > Hey thanks a lot guys, I'll go along with Chuck's idea, it makes
> > complete sense. I saw a 16v 944 got a broken spring and it had a
> > variable miss, lucky thing the inner valve apring kept it all together
> > and valves never got mashed, just replaced the spring and that was OK
>
> Update: Finally decided to pull that head out, and I gotta say CHUCK
> YOU"RE RIGHT!!! upon removing the valve cover, i pushed on the 2 exhaust
> lifters and found the rear one went down under slight pressure. Took the
>   head down and yes sir bent valve enough to see light thru the seat.
> Orser my parts and she will be fine again. THANKS CHUCK!!- Hide quoted text -
>
> - Show quoted text -

So hopefully the top of the piston is ok, and no other damage
occurred. If you haven't done so, check it out before you order parts.
 >> Stay informed about: 88 rocco:No compression cyl#4!?? 

Chuck wrote:
> On Feb 5, 4:28 pm, Regal953 <regal....TakeThisOut@comcast.net> wrote:
>> Regal953 wrote:
>>> Chuck wrote:
>>>> Most likely a valve spring broke or the retainer that holds the valve
>>>> to the spring let go. The tapping noise might be the piston hitting
>>>> the valve. A friend of mine had this kind of thing happen with his
>>>> '68 Datsun. Since the engine was already not 100%, he elected to
>>>> replace it with another crated engine he had had in the backyard for
>>>> many years, although he did not finish the install, since other stuff
>>>> came up. In your case, you can probably fix whatever is broken with
>>>> the valve assembly.
>>>> On Dec 4, 8:03 pm, one out of many daves
>>>> <NOSPAMvwd....TakeThisOut@hotmail.comPLEASE> wrote:
>>>>> 16V or 8V engine?
>>>>> Do the spark plugs still look fine?
>>>>> Might want to do a Leak Down Test to find out where the compression is
>>>>> going to. Also might want to pull the valve cover to peak at the
>>>>> lifters/followers and camshaft(s).
>>>>> Not sure here! <
>>>>> Regal953 wrote:
>>>>>> Maybe Dave has an idea, engine was running fine, all of a sudden I feel
>>>>>> a heavy miss after hearing lifter-like tapping noise. Pulled plugs and
>>>>>> compression is zero in cyl # 4. What could have caused valves to stick
>>>>>> open? Cyls 1,2,3 are fine at 170psig. Timing belt is fine in synch.
>>>>>> ???- Hide quoted text -
>>>>> - Show quoted text -
>>> Hey thanks a lot guys, I'll go along with Chuck's idea, it makes
>>> complete sense. I saw a 16v 944 got a broken spring and it had a
>>> variable miss, lucky thing the inner valve apring kept it all together
>>> and valves never got mashed, just replaced the spring and that was OK
>> Update: Finally decided to pull that head out, and I gotta say CHUCK
>> YOU"RE RIGHT!!! upon removing the valve cover, i pushed on the 2 exhaust
>> lifters and found the rear one went down under slight pressure. Took the
>> head down and yes sir bent valve enough to see light thru the seat.
>> Orser my parts and she will be fine again. THANKS CHUCK!!- Hide quoted text -
>>
>> - Show quoted text -
>
> So hopefully the top of the piston is ok, and no other damage
> occurred. If you haven't done so, check it out before you order parts.
Checked it right away, piston crown fine, parts ordered, first batch
came in today, great stuff. Valve's slightly bent. I'm removing the
headers and collector and going back to stock exhaust manifold and
downpipe, already bought on ebay. Headers anyone?
 >> Stay informed about: 88 rocco:No compression cyl#4!??