97 expo dont run right

[strokin393]

READ POST #46 AGAIN I EXPLAINED IT ALL IN THAT POST. I TOLD YOU IN THAT POST THAT YOU DO NOT NEED TO GET THE LEAK DOWN TESTER KIT, AND THAT ALL YOU NEED TO DO IS USE THE COMPRESSION TESTER HOSE BUT TO MAKE SURE THAT YOU PULL THE SHRADER VALVE OUT OF THE BOTTOM FIRST! THEN HOOK IT TO AN AIR COMPRESSOR AND LISTEN FOR WHERE THE AIR IS COMING FROM.

As for the amount of air use the regulator on the compressor and turn it down to about 75PSI. That will be more than enough so that you can hear / feel where the air is going.

Yeah, I remember you saying I could use that, but I didn't know about how much air. I guess I'll try this out and see what happens. Thanks

 

[markanthony]

1. Pick up the compression tester. Their should be a little valve. it looks like the inside of the tire valve. You will need to remove that valve.. A bike shop has a tool for that, or the local parts store. Go to the isle that has tire related things (or ask the guy at the counter) Their may be a kit that has replacement valves plus tire valve caps etc. Some of these kits have the valve remover. Hear is a link for suck a goodie from my local store.. This will give you an idea of what I am talking bout.

2. Pull the off and set aside.
3. Remove the spark plug.
4. Find a socket that fits the harmonic dampener pulley. It's a big bolt. The pulley is the very bottom on the engine. The bolt could be as big as 20mm up to 1 1/4 inch.
5. screw in the compression tester hose into the hole.
6 Hold your thumb on the other end, and turn the socket. By doing this. You will feel pressure build up. This lets you know that valves are closed. You should also feel the socket on the pulley bolt turn hard, then real easy. AT THIS POINT. STOP TURNING THE SOCKET.
7. Now remove the compression hose.
8. insert a long flat blade screw driver in the hole. You should be able to feel the piston. if the screw driver falls in with out stopping. You will need to move the piston up more.. SEE STEP 8a
8a. turn the socket on the pulley till you see/feel the screw driver move up.. YOU DO NOT NEED TO TURN THE CRANK FAST. BY DOING THIS FAST WILL DAMAGE TOP OF PISTON. When the screw driver stops moving up and starts done. STOP. YOU ARE NOW TOP DEAD CENTER.
10. reinstall compression hose. attach air hose..
11. make sure air tanks are set to 75 to 100 psi and far enough away. This will give you quite time to hear air leaks.
12. start compressor. let air build up in the cylinder (bout 5 min should be more then enough)
12. listen for air leaks..
13. open oil fill cap. listen. ( possible bad piston rings. Rebuild motor)
14. open coolant over flow and listen. (warped head, head gasket, bad valve)
15. take apart intake hoses.
16. Pull throttle and listen. (warped head, bad valve, head gasket.)
17. write down Cylinder number and were you heard the air. (oil, TB, water.)
18 repeat proses for all cylinders.


If you hear air from coolant over flow, or TB. You need to have the head fixed up. You will need to pull the top end of the engine apart to get to heads. Take the heads to a machine shop and have them worked on..

If you hear air from the oil fill tube. You will need to rebuild the engine or buy another one. This is an indication of bad rings, or scored cylinder wall.



DISCLAIMER. YOU WILL NEED BOTH HEADS DONE. WHEN THE HEAD COMES OFF. THEY WILL NOT FIT BACK ON CORRECTLY UNTIL THEY ARE "DECK" OR "MILLED". THIS IS DONE BY THE MACHINE SHOP..

 

[markanthony]

Heads.
When a machine shop works them. They should remove all the parts to them (see note A) They attach the head to a machine, that will plain the head to a flat level surface. This is called "deck" or "milled" my local shop will use both terms.
When the install the parts back in. Most of the time. When they install valves. most of the time they will install new valve guides. (at least my local guy will if they are bad)
IMO, This is what makes a good shop..

note A. parts to a head. there may be different little parts not listed hear. this is to give an idea. there is the rocker Assembly, studs, springs, valves, valve guides.

 

[strokin393]

Thanks for all the info. Can someone give me stap by step instructions on taking the pass side head off and on? Thanks

 

[strokin393]

You do not need much, a cap full should be more than enough.

If the numbers did not go up considerably, then I would deffinatly say " do the leak down test ".

The leak down test will tell you where the lost compression is going that way you know what you are up against.

The easiest way to do the leak down test is to use the same hose you used for the compression test, BUT MAKE SURE YOU REMOVE THE SHRADER VALVE FROM THE END ( if you do not do this, no air will travel into the cylinder ).

You really do not need any special gauge to do the test, just put the compression tester line into the spark plug hole ( after removing the valve in the end ) and conect it to an air compressor ( make sure that the cylinder you are testing is at TDC and also make sure the compresser is far enough away that you can hear the air moving thru the motor ). Listen to your Exhaust, take the air intake off and open the throttle body and listen, also take off the oil filler cap and listen, and lastly take off the coolant tank cap and listen.

Air coming from Exhaust = Burnt or damaged Exhaust valves
Air coming from Intake = Burnt or damaged Intake valves
Air coming from oil fill = Bad rings, blown head gasket between cylinders, or warped head
Air coming from coolant tank = blown head gasket or warped head

Basically from the info you are giving I would say that the " short block " ( pistons, rings, bearings, block, ETC. ) is ok, but it does sound like the truck may have been severly overheated and either took out a head gasket or warped a head.

Usually if you have just one or two cylinders with lower numbers I would say bad valves, but to have a full bank with low numbers I am leaning towards a warped head.

If you do have a warped head you have a couple of options. You can take both heads to a machine shop and have them " deck " the head surface ( make it level again ) and while they are at it full vavle job ( roughly $200 per head ).

You can find a set of heads out of a wrecking yard. You can get the heads used from a wrecking yard off of any 5.4L from the same year ( Expy, F150, Super Duty ) as they are all the same ( roughly $ 200 ).


You can buy NEW heads ( this would be the most expensive route around $400 each for after market replacements which are usually remanufactured but come with a 1 yr waranty )

Or if you would like to up the power a little bit you could get a set of heads from a 2000 - 2002 wich are the PI heads. These heads will give you a +/- increase of 30 HP. If you do decide to go this route, you will need the intake off of the same year as well, becuase yours will not line up. If you go this route make sure to get the valve covers as well because in these years they had the Windsor and the Romero ( head mounting is all the same but the valve cover mounting is different ).

I just did number 1 had no way of keeping motor from turning so I let it turn and kept air going in and hear it coming out the oil filler neck.

 

[strokin393]

Number 2 air coming out tb without being on tdc. I'm just putting air in without trying to put on tdc because it moves anyway and I have no one to help me. So what could it be? How can I tell if its a valve or head gasket?

 

[strokin393]

Ok, I tested number 1, 2, and 3. Number 1 and 3 sounds like its coming from oil filler but not much and when I unhook the air its got a lot of air built up like its not leaking and when I unhook number 3, no air comes out so its leaking in motor and that's the one that's letting air come out throttle body. I don't know what to do.

 

[strokin393]

I wasn't thinking about the valves being open.

 

[strokin393]

When I get someone here to help me, I'm going to do the leak down test and post the outcome.