Been about a year since it last ran and I'm testing the psi before I get any further. Front timing cover is off still and I was curious if I need to oil specifically anywhere. No oil is in it atm but it will most likely spurt out the front engine when I try to turn it over when testing. Cams are on the engine heads but not being held down tight, the bolts that hold them in place are just a few threads deep so the cams aren't putting any pressure on the valves. I was thinking about putting a little oil down inside the actual cylinders and maybe just put a little in the crankcase. Is there anything I'm missing here

 

First off what was done to the heads. Next don't crank the motor. Your best bet would be to do a leak down test to see if everything is good. I dont know if you have the chains on yet but if you do and the cams are loose you could strip the threads in the cam caps. I would think you dont have the chains on because I don't know how you would time it with them loose. If you try to crank it without the cam and chains on there is no way for air to get in or out of the cylinders.

 

Well one of the valves got bent due to timing issues so I rebuilt the heads after inspecting all the cylinders and finding it was salvageable. The chains are off and nothing is connected to the cams. I'm using a psi test kit, the particular extension that I'd be using in this case doesn't screw in so some air would be able to pass through. Its rubber on the end.

 

 

I ended up buying a leak down tester. All of it was good except for one valve, it was the intake valve that was replaced by the machine shop. It leaks air out of it. Could the valve have dirt in it or could it be blocked by something? I don't think it's closed properly and if I can't figure this out I'm going to have to take that engine head off, will the seals and engine head bolts still be good? They are torqued to yield.

 

The time to check compression is when everything is torqued up and you've got it to the point of running. The time honored way.
Pull the fuel pump relay and add the correct amount of engine oil, then dry crank so it gains oil pressure and lubricates everywhere.
Without oil the crank could pick up a bearing then you've way bigger problems.

 

I recently had my engine heads rebuilt and had them replace one of the intake valve stems because it was damaged. Engine was still salvageable so I went ahead and took the engine heads to a machine shop. I finished torquing the engine heads back on last week. Today I did a leak down test on all the cylinders and I get to the area where the valve stem was replaced and it leaks. Could this be a bad valve spring? If so is there any way to replace this spring without having to take the engine head back off? I'm going to call the machine shop Monday and ask them what's going on. Maybe there is dirt down in there. Atm I cannot turn the engine over because I have the timing chains off and the covers off, so I decided to try a leak down test and I found this leak. Please let me know your opinion, I've spent a lot of time on this car and I don't want it wasted.

 

IMHO you don't need a compression test. If you failed the leak down test you going to have a low compression in that cylinder. How do you know it is the intake valve. When you adjusted your valves, I assumed you adjusted the clearances, that valve would have a bigger clearance than the rest. Are you sure the piston wasn't damaged.

 

Did you look at the combustion chamber side of the head prior to putting it back on the engine?

 

Pull the camshaft out and remove the lifter(s). Using a wood dowel or brass punch you can smack the valve stem and watch the pressure gauge.

There are the piston rings to consider. Just because the cylinder leaks it might not be the valves.
I would pull all the cams and put a little oil down all the spark plug holes and crank the engine over to distribute the oil.

No valve will open so no valve will be damaged with the cams OUT.

bob

 

Dupe:

https://www.jaguarforums.com/forum/x...0/#post1666521

 

I know it's the intake valve because I have the intake manifold loose and I stuck my finger down in there and during the test that's the only place I felt air escaping

 

I answered your other thread. 1 thread for a problem please.

Can you hear where the air is leaking. Intake, exhaust, or crankcase. Take Bob's advice and oil the cylinder and test again. If you cleaned the clylinder there may not be enough oil to seal the cylinder. I oil down all cylinders before installing the heads.

 

The cylinder doesn't leak, I have the intake manifold loose and during the leak down test I stuck my finger down the intake and that was the only valve that I felt air escaping from

 

I oiled the walls of the cylinder before installing the heads

 

Did you have a machine shop do the work? If so exactly what did they do? The valve seat may have damage. When I do valves I will turn the head upside down and put clean solvent in each cylinder and let it set for a coiple hours to find leaks.

 

I had a machine shop do the work, they cleaned up both engine heads and made sure no cracks or anything was involved and then they replaced one valve stem on the passenger side head, which is the one that is leaking currently. Originally, I assume from what I inspected before the rebuilt occurred, that the timing slipped a cog and this valve got damaged, I made 100% sure that the cylinder was ok before proceeding. It had some Carbon buildup but nothing was cracked. So I took it to the machine shop and they did their work on it, I ordered the valve directly from the jaguar dealership. This machine shop is pretty reputable, they do some of the cars that are in the barret Jackson auction, but I'm definitely calling them on Monday when they open to ask exactly what they did

 

You have the cams partially installed. Is it possible the lobe is compressing the valve a little?

 

I took the intake cam off earlier and tested it again, still was leaking air. I even tried compressing it to see if it was just dirt or something stuck on the valve and nothing happened. However, the first time I tested it, I heard a pop, idk if that means anything but I took the bucket off with a magnet and the one next to it, I saw a difference, there is some white grease around it and on the one that is leaking I see some grease kinda splatter around it. It could just be because it wont close on the bottom but I thought I'd mention it

 

Call your machine shop and let them know whats happening. Let them decide how to proceed.