grahamtwatson
NAXJA Forum User
- Location
- Woodinville
I'll be replacing the Cylinder Head on my 90 4.0L this weekend, and was wondering if anyone has any suggestions as to what to look for whilst the head is off - I'm considering also replacing the rings, big ends and the oil pump at the same time -the engine has done over 200k miles and the oil pressure is somewhat low - 10~15 psi at hot idle, there is a definite knock from the bottom (louder when cold and especially when the engine first starts) and the compressions are on the low side but OK.
Any suggestions as to whether this is a good idea or not would be appreciated - I've searched and seen all sorts of opinions, and I'm in two minds myself as to what to do - I could replace the rings with the engine in the car, but would this improve compression necessarily - the old rings should be nicely bedded in by now ;-) - same thing applies to the big ends - replacing the bearings *may* actually be a bad move, given that the current bearings will be the same general shape as the crank, just bigger....
So ... replace rings, big ends and oil pump at the same time as the head, or just throw the new head on and step away? Anything in particular I can look for whilst the head is off to help make my mind up one way or the other?
Thanks everyone....
Graham
Any suggestions as to whether this is a good idea or not would be appreciated - I've searched and seen all sorts of opinions, and I'm in two minds myself as to what to do - I could replace the rings with the engine in the car, but would this improve compression necessarily - the old rings should be nicely bedded in by now ;-) - same thing applies to the big ends - replacing the bearings *may* actually be a bad move, given that the current bearings will be the same general shape as the crank, just bigger....
So ... replace rings, big ends and oil pump at the same time as the head, or just throw the new head on and step away? Anything in particular I can look for whilst the head is off to help make my mind up one way or the other?
Thanks everyone....
Graham