Justin McDonald

Hello, I'm hoping for some sort of advise, I'm just stumped...

I just rebuilt the 5.4l dohc 32v in my 2000 lincoln navigator, and it has no compression. It feels almost as if the spark plugs aren't in it or the valves are not opening and closing. not one of the cylinders has any compression. The timing was set right, the single color links at 6 o'clock on the bottom, and the double color links at 11 o'clock passenger side and 12 o'clock driver side. it turns over smooth and has no problems turning and doesn't/didn't make noise. do the lifters need to be primed?

history:

I bought the truck with the engine already slightly disassembled and it had sat for over a year, so I had the engine bored .030 over and the crank ground .010 over. the new bearings and pistons/rings all fit perfect!

The guy at the machine shop said the heads looked fine, and that I shouldn't need any valves or anything other than a resurface. Now I know one head was rebuilt, as the valves looked brand new and one piston from that side did have valve scars.

I have already installed the engine back into the truck and I'm hoping I just need to do something stupid like keep priming oil to the lifters or maybe the plugs I got just aren't all the way in. any tips? any advise on what I should check or what my next move should be?

bubbabud

1st remove plug run a compression test if no compression then it is a valve or timing problem. I must assume the pistons and rings were sized and installed properly.
No disrespect but I actually run into a case where an engine was bored oversize and assembled with the stock pistons and rings. so if the bottom end is correct then the problem has to be in the heads. Good luck sorting it out.

PerryB

From the basic description it sure sounds like valve timing.

Justin McDonald

ok, so i couldn't find a timing description online for the dohc that showed which way the smaller cam gears markers should be (i assumed they would always line up with the larger gear since they are mated together) could they be out of adjustment? i only checked where the marks on the larger cam gears that connect the chain to the crankshaft? the car is at my father in laws 60 miles away so i cant go out and look for sure, but i called my father in law last night and we both agreed that it was either the HLA's are not primed with oil, he said i should've soaked them in oil over night, or the cam gears were out of sync. is there more than one way to install the larger cam gears? because the machine shop did have the cam gears off too, maybe they installed them upside down?

sorry for the poor grammar and all the questions, but i do appreciate the advice. thanks

PerryB

I THINK even with collapsed lifters you'd have enough valve opening that it would run.

papa tiger

I would pull the covers and bore scope it to find out if the valves are out of time. All valves in each front cylinder should be closed during the compression stroke. If not than you have to figure out your timing snafu. Also check to see if throttle body plate opens. Open it an put something to hold it open or take it loose and hand crank to check compression again on compression stroke. also you should feel vacuum on intake stroke. No vacuum engine can't run. Usually if your parts are right and your timing off a little cause you messed up it will back fire. If all chain timing is right then you messed up the parts.

U will need to retime and do it right this time probably

Justin McDonald

so i tore it back down, and the timing was all set right, the cams were synced right, and the cams to crank were also correct. #1 at tdc all valves were closed, #2 at tdc all valves were closed and so on, funny thing is, when i crank it over by hand i can hear compression seeping out, but the compression tester doesnt even move when cranking it with the starter... i also tried 2 different testers in case one wasnt working...

maybe my rings havent seated? if so how would i go about seating them? i was told pour some oil into the cylinders and i tried it with the #1 piston and had no change.

i pulled the cams off and i am soaking the lifters in oil (they were firm but just in case), will update when i go down on saturday and put it back together.

bubbabud

Set number 1 at TDC on compression stroke buy or make a fitting to apply compressed air to that cylinder through spark plug hole and listen for the escaping air. If it is escaping into the crank case its rings if it is escaping from the exhaust or intake it is valves.

papa tiger

Does the engine have vacuum when cranking it ? No vacuum = little or no compression and again back to valve timing or damaged parts or wrong piston/ring set.