Mule89
OBS Enthusiast
So what should have been a simple swap has kinda turned in to a huge head ache dealing with ignition. This is a 99 vortec block with stock cam lifters and heads the rotating assembly is from an 89 TBI engine (extremely low budget rebuild) all new bearings and also has a big block chevy oil pump because I was tired of screwing with the low oil pressure that kill 3 of the 4 engines. When you crank it over it sounds like only 4 cylinders are hitting but it also blows out the throttle body like it has a intake valve not closing all the way, and it is getting plenty of fuel. I have already confirmed it's not 180° out of time. My thought is the rat pump is pumping up the lifters so much that it opens the valves a bit. Usually my dad or my Automotive Shop teacher know what is possibly going on but when I explain and and showed everything to my dad he said "I have no idea" and we are on spring break so can't really get a hold of my shop teacher on tips to eliminate the possible problems because he used to be a GM dealer tech that worked on these trucks brand new and he also has OBD1 scan tool that with live display. I'm trying to figure it out but I'm only 18 I don't have the experience to know what I need to do. I should also note that I'm using 10w-30 should I run a thiner oil like 0w-20 so that the lifters are not being pumped up so quickly or am I way off and sound like a mad man? I'm just really wanting to hear it run because it is my favorite truck. I do not have a compression tester but might be able to come up with something.
This engine is going to eventually have a turbo on it but I just want to get it running good with out it before I do that also another reason I used the big block oil pump. If anyone can help me out with this it would be greatly appreciated.
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This engine is going to eventually have a turbo on it but I just want to get it running good with out it before I do that also another reason I used the big block oil pump. If anyone can help me out with this it would be greatly appreciated.