Help! doing the 4.0 head swap on a 258!
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
Have you made sure the timing chain is on right? If the chain is not
installed correectly, there is no telling where the cam is going to be. the
chain must be installed with the crank in the right spot. Actually, the
crank and cam are keyed, you can be off by half because the crank goes
around twice for each rotation of the cam. It sounds like #1 isn't in the
front anymore.
And, I think you probably should be using the 4.0 rockers, etc. I am not
sure on that though.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> Folks, I'm in a pickle!
> Hope you can help me. I'm in the process of doing the head swap on my '86
> CJ7. Got the head installed no problem. Here's my catch, when I went to
put
> the 258 stock rockers and pushrods back in, my valves were opened on #1
cyl
> when its at TDC. AS we all know this is not good for compression.
Apparently
> either my pushrods are too long or something in the rockers is amiss. Got
> any ideas? Should I be using 4.0l rockers, pivot assemblies, and pushrods
> instead of the old 258 engine parts?
> Thanks for your help.
> Rich Harris
>
>
installed correectly, there is no telling where the cam is going to be. the
chain must be installed with the crank in the right spot. Actually, the
crank and cam are keyed, you can be off by half because the crank goes
around twice for each rotation of the cam. It sounds like #1 isn't in the
front anymore.
And, I think you probably should be using the 4.0 rockers, etc. I am not
sure on that though.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> Folks, I'm in a pickle!
> Hope you can help me. I'm in the process of doing the head swap on my '86
> CJ7. Got the head installed no problem. Here's my catch, when I went to
put
> the 258 stock rockers and pushrods back in, my valves were opened on #1
cyl
> when its at TDC. AS we all know this is not good for compression.
Apparently
> either my pushrods are too long or something in the rockers is amiss. Got
> any ideas? Should I be using 4.0l rockers, pivot assemblies, and pushrods
> instead of the old 258 engine parts?
> Thanks for your help.
> Rich Harris
>
>
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
Spin the crank one full rotation.
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
Spin the crank one full rotation.
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
Spin the crank one full rotation.
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
Spin the crank one full rotation.
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
the crank goes around twice for every rotation of the cam, so the crank can
be at the top on one rotation, and the valves are in transition between
exhaust open and intake open. You would have troubles putting the pushrods
in if this were the case.
Having said that, the rockers and pushrods on the 4.0 could easily be
different than on the 4.2.
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> The distributor position is irrelevant in this case. The valves are open
> because either the pushrods are too long or the rockers are of an
incorrect
> design for this head. I never removed the distributor during this whole
> operation. All I did was pull the old head and bolt on the new.
> "Jo Bo" <jromas@columbus.rr.com> wrote in message
> news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > Maybe a dumb question but have you checked the position of the
distributor
> > rotor for pointing to #1 cylinder? If not try turning the crank 360
> degrees.
> >
> > JoBo
> >
> > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > Folks, I'm in a pickle!
> > > Hope you can help me. I'm in the process of doing the head swap on my
> '86
> > > CJ7. Got the head installed no problem. Here's my catch, when I went
to
> put
> > > the 258 stock rockers and pushrods back in, my valves were opened on
#1
> cyl
> > > when its at TDC. AS we all know this is not good for compression.
> Apparently
> > > either my pushrods are too long or something in the rockers is amiss.
> Got
> > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> pushrods
> > > instead of the old 258 engine parts?
> > > Thanks for your help.
> > > Rich Harris
> > >
> > >
> >
> >
>
>
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
You use the 4.2 ones.
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
You use the 4.2 ones.
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
You use the 4.2 ones.
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
You use the 4.2 ones.
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Mike
CRWLR wrote:
>
> Spin the crank one full rotation.
>
> the crank goes around twice for every rotation of the cam, so the crank can
> be at the top on one rotation, and the valves are in transition between
> exhaust open and intake open. You would have troubles putting the pushrods
> in if this were the case.
>
> Having said that, the rockers and pushrods on the 4.0 could easily be
> different than on the 4.2.
>
> "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> news:xLoSc.1431$aB1.1397@twister.socal.rr.com...
> > The distributor position is irrelevant in this case. The valves are open
> > because either the pushrods are too long or the rockers are of an
> incorrect
> > design for this head. I never removed the distributor during this whole
> > operation. All I did was pull the old head and bolt on the new.
> > "Jo Bo" <jromas@columbus.rr.com> wrote in message
> > news:08mSc.11877$Nl1.1300@fe1.columbus.rr.com...
> > > Maybe a dumb question but have you checked the position of the
> distributor
> > > rotor for pointing to #1 cylinder? If not try turning the crank 360
> > degrees.
> > >
> > > JoBo
> > >
> > > "Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
> > > news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> > > > Folks, I'm in a pickle!
> > > > Hope you can help me. I'm in the process of doing the head swap on my
> > '86
> > > > CJ7. Got the head installed no problem. Here's my catch, when I went
> to
> > put
> > > > the 258 stock rockers and pushrods back in, my valves were opened on
> #1
> > cyl
> > > > when its at TDC. AS we all know this is not good for compression.
> > Apparently
> > > > either my pushrods are too long or something in the rockers is amiss.
> > Got
> > > > any ideas? Should I be using 4.0l rockers, pivot assemblies, and
> > pushrods
> > > > instead of the old 258 engine parts?
> > > > Thanks for your help.
> > > > Rich Harris
> > > >
> > > >
> > >
> > >
> >
> >
Guest
Posts: n/a
Re: Help! doing the 4.0 head swap on a 258!
See following article:
http://monsterslayer.com/jeep/40Head/40Head.htm
The way I read it, use all 4.0L parts regarding the head and 4.2L parts from
the pushrods down.
Bill
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> Folks, I'm in a pickle!
> Hope you can help me. I'm in the process of doing the head swap on my '86
> CJ7. Got the head installed no problem. Here's my catch, when I went to
put
> the 258 stock rockers and pushrods back in, my valves were opened on #1
cyl
> when its at TDC. AS we all know this is not good for compression.
Apparently
> either my pushrods are too long or something in the rockers is amiss. Got
> any ideas? Should I be using 4.0l rockers, pivot assemblies, and pushrods
> instead of the old 258 engine parts?
> Thanks for your help.
> Rich Harris
>
>
http://monsterslayer.com/jeep/40Head/40Head.htm
The way I read it, use all 4.0L parts regarding the head and 4.2L parts from
the pushrods down.
Bill
"Harris Family" <SHARRIS11nospam@san.rr.com> wrote in message
news:gJeSc.3870$Qa4.538@twister.socal.rr.com...
> Folks, I'm in a pickle!
> Hope you can help me. I'm in the process of doing the head swap on my '86
> CJ7. Got the head installed no problem. Here's my catch, when I went to
put
> the 258 stock rockers and pushrods back in, my valves were opened on #1
cyl
> when its at TDC. AS we all know this is not good for compression.
Apparently
> either my pushrods are too long or something in the rockers is amiss. Got
> any ideas? Should I be using 4.0l rockers, pivot assemblies, and pushrods
> instead of the old 258 engine parts?
> Thanks for your help.
> Rich Harris
>
>