engine cranks like its got a busted timing chain

[williambavila]

I have came across 2 engines lately that seem to crank like a busted timing chain or broken timing gears. They turn over like there is no compression and clacking. I have removed 1 and disassembled it looking at each piece carefully. I cannot see anything damaged. The only 2 possibilities that pop into my head are 1) the engine lost its prime and lifters are not pushing the pushrods up but it should not rotate as freely as possible. 2) the lifters are stuck up causing the valves to hang open regardless of position. I recently heard someone say it could be caused by the little plunger in the oil pump hosing being stuck. Has anyone had this issue or ran across it?

 

[RmvBfrFlght]

On a NA Regal 3.8 had a piece of the plastic upper gear teeth hold open the oil pump pressure regulator valve. No power and the valve train was noisy as hell.

RemoveBeforeFlight

 

[williambavila]

On a NA Regal 3.8 had a piece of the plastic upper gear teeth hold open the oil pump pressure regulator valve. No power and the valve train was noisy as hell.

RemoveBeforeFlight

Yeah these were both turbo cars
they wont start sounds like the chains busted but they are fine I removed the timing cover

 

[RmvBfrFlght]

They both use the same oil pump and plastic upper cam gear.

RemoveBeforeFlight

 

[williambavila]

They both use the same oil pump and plastic upper cam gear.

RemoveBeforeFlight

yes but both have been changed to steel gears at some point

 

[williambavila]

like I said they both should fire up, they had been running at some point but they sat and this happened. 1 was on a car in illinois and one here in okc.

 

[Pronto]

Did you pull the valve covers to see what's going on when you crank it?

 

[williambavila]

yes the rockers seem to move very little, like the lifters are collapsing while pushing up

 

[evolved]

what were you seeing for compression out of the cylinders?

 

[Turbo6inKY]

Cam lobes could be wiped out.

 

[Pronto]

Sounds like at a minimum you're going to have to pull the manifold.

 

[bpman1234]

check the cam sensor maybe the pin that holds the cam gear in place broke.

 

[williambavila]

check the cam sensor maybe the pin that holds the cam gear in place broke.

the cam sensors are fine. If you read the post the engine is torn completely down to find the issue, the only 2 options I can think of were listed above I wanted to see if anyone has ran into it

 

[williambavila]

what were you seeing for compression out of the cylinders?

some times it would turn over as if it was a normal starting situation others it would turn over as if there was no compression thats why I pulled the timing cover to see if the cam gear was bad. it was not which then pointed me to look at the lifters and the travel there. the cams in both engines are not flat the one engine is on a stand disassembled and there is no damage to anything.

 

[williambavila]

Guys I am no rookie with these engines. I have only encountered this 2 times in 10+ years of building these. I am asking if anyone has seen a plunger stick in the oil pump gear set cover or if they have seen lifters cause a issue like this. I do not need to look for a flat cam it is perfect,timing chain and gears are perfect there is no damage or broken parts. It just acts as if there is no compression at time and others it sounds normal while cranking.

 

[forcefed3.8's]

There is a guy in OK that helps everyone that asks. Maybe call him

 

[psycho6cyl]

This site has been pretty slow lately. You maybe better off hitting up facebook groups grand national tech or tirbo farm or even house wives of turbo buick....

 

[michael evans]

the cam sensors are fine. If you read the post the engine is torn completely down to find the issue, the only 2 options I can think of were listed above I wanted to see if anyone has ran into it

While you have it apart, I would have the valves checked.

 

[Pronto]

Have you manually pushed the lifter pocket down to see if it pushes back up? How is the rest of the engine? Does it show signs that junk went through it? I suppose some gunk could be messing up the lifters and allowing them to stick.

 

[williambavila]

Have you manually pushed the lifter pocket down to see if it pushes back up? How is the rest of the engine? Does it show signs that junk went through it? I suppose some gunk could be messing up the lifters and allowing them to stick.

the lifters seem to have no pressure like a "new" lifter. I am assuming that is the issue like the car lost the prime. I was curious to see if this has been anyone else issue. I have never seen one that has lost its prime. now 2