oil pressure issues and more after engine rebuild and mod
#1
oil pressure issues and more after engine rebuild and mod
ok well heres what i did
i put a .490 lift flat tappet cam for a 350 (no cam buton) into my roller 305 (had cam button) new comp cam flat tappet lifters for a 350
new clevite 77 main bearings and connecting rod bearings (all clearanced to .15 after install) molly assembly greased everything. vortec heads btw with factory rockers and comp cam springs and valves
also added 3 1/16in thick washers behind the pressure spring in my oil pump (somewhere around .187 in)
running 10w30 motor oil with bosh filter
now it ran great for days then the first time i ran a pas to tune it better my oil pressure problem began.
now as it warms up to 220* oil pressure gradually drops from 40 psi at idle cold to 2psi at idle hot you can watch it drop as temp rises
heres the other odd thing when cold and hit WOT my aftermarket oil pressure gauge which max is 110psi wraps all the way back around to 0 at 5k rpm which from what i can guess by gauge would be between 120-140psi this does not happen when warmed up which id be lucky to hit 60psi wot
im thinking about running seafoam in the oil to clean any debris out
then after a couple days switch to WIX oil filter and VR-1 20w50 motor oil with a bottle of zinc additive
should i replace the oil pump? i checked for play between the gears and everything cam out to under .010 play (oil pump is original with 280k miles) seemed to be fine with only .008-.010
play i dont think i would get 140 psi with bad pump
ANY INPUT WILL HELP... i don't want to blow the engine just yet...not untill i can build my 383 swap for it
i put a .490 lift flat tappet cam for a 350 (no cam buton) into my roller 305 (had cam button) new comp cam flat tappet lifters for a 350
new clevite 77 main bearings and connecting rod bearings (all clearanced to .15 after install) molly assembly greased everything. vortec heads btw with factory rockers and comp cam springs and valves
also added 3 1/16in thick washers behind the pressure spring in my oil pump (somewhere around .187 in)
running 10w30 motor oil with bosh filter
now it ran great for days then the first time i ran a pas to tune it better my oil pressure problem began.
now as it warms up to 220* oil pressure gradually drops from 40 psi at idle cold to 2psi at idle hot you can watch it drop as temp rises
heres the other odd thing when cold and hit WOT my aftermarket oil pressure gauge which max is 110psi wraps all the way back around to 0 at 5k rpm which from what i can guess by gauge would be between 120-140psi this does not happen when warmed up which id be lucky to hit 60psi wot
im thinking about running seafoam in the oil to clean any debris out
then after a couple days switch to WIX oil filter and VR-1 20w50 motor oil with a bottle of zinc additive
should i replace the oil pump? i checked for play between the gears and everything cam out to under .010 play (oil pump is original with 280k miles) seemed to be fine with only .008-.010
play i dont think i would get 140 psi with bad pump
ANY INPUT WILL HELP... i don't want to blow the engine just yet...not untill i can build my 383 swap for it
#2
also runs hotter than it used to ...i have dual electric fans with both on id barely hit 110* (before rebuild) now with both on i run at 220* engine warms up very fast (under 5 min.) im not running a thermostat and i have a high flow water pump
Last edited by 1989_RALLYSPORT; 06-24-2011 at 03:18 PM.
#3
adding the spacer to the spring more than likely over pressureized the oiling system and spun a bearing. with 280k the pump should have been replaced. chances are there are passages blocked off with carbonized oil. did you get the correct push rods to work with the flat tappet cam? also no thermostat and a high flow water pump is the heat issue, the coolant isnt staying in the rad long enough to cool. you need to use a water restrictor if not using a thermostat. could be other issues, but start with that
Last edited by microkid; 06-24-2011 at 06:54 PM.
#6
3/16 of an in shuldnt be any big deal.. ive put up to 1/4 in into some of my old cars which raised my oil psi by 22+psi
at most my normal psi range should have gone up by 10-15psi max
at most my normal psi range should have gone up by 10-15psi max
#9
This sounds crazy to me, at that pressure you would most likely be pusing oil out of the dipstick, intake manifold bolts, probobly split the sending unit in two. On the back of the block behind the dizzy there is a pipe thread plug, try a mechanical gauge there. Something is odd, I would agree with micro that spacers are not necessary. Its like you're screwing with us...
#10
IM NOT SCREWING WITH ANYONE...I have my brand new mechanical autometer oil psi gauge hooked to oil port on front of the block just above the timing cover.
im just as stumped as you guys
i will be replacing oil pump next week if i cannot figure this out.
and yes my oil filter did balloon out
im just as stumped as you guys
i will be replacing oil pump next week if i cannot figure this out.
and yes my oil filter did balloon out