WhiteLX
New Member
- Joined
- Sep 17, 2007
- Messages
- 44
- Reaction score
- 0
- Points
- 0
- Age
- 46
- Location
- So Cal
- Vehicle Year
- 1989
- Make / Model
- Ford
- Engine Size
- 2.9L
- Transmission
- Automatic
I performed a compression test on my 89 Ranger with a 2.9L this evening. I bought the truck back from the fellow I sold it to 9 months ago because it developed a horrible miss.
I pulled the plugs and every single one of them were black, except #2. The previous owner replaced all of the plugs when it developed the miss, so they were not in but maybe a week. The one he pulled out of #2 when he changed plugs looked bad, really bad. I couldn't tell from the image if it were damaged or just horribly oil fouled. So back to the plugs I pulled out. #2 smelled like gasoline. I changed all of the plugs and found the vacuum hose unplugged from the fuel pressure regulator. I figured it was just dumping a bunch of fuel in. Not the case, still a dead cylinder.
Time for a compression test...
The engine was run idle for about 5-10 minutes to get a little heat into the engine. Today was in the 80s, so it wasn't terribly cold. I propped the throttle open and let the engine rotate until pressure stopped increasing. This was probably about 10 revolutions.
#1 = 190psi
#2 = 0
#3 = 190psi
#4 = 185psi
#5 = 185psi
#6 = 185psi
Obviously a problem with #2. Other than the obvious, how do the rest of the numbers look? They are remarkably even across the board, which I guess confirms the engine was rebuilt at some point in it's life. The chassis has 300K on it now. What is the typical compression numbers from a stock 2.9L in good health?
There was a slight tick coming from the top end on the left bank when the engine was running. I figured maybe a broken valve spring or rocker issue. I pulled the valve cover and everything looks normal. I rotated the engine and nothing out of the ordinary.
So I connected the air hose to #2 and took a listen. I only had about 80 PSI available to me as it was past 10PM and I didn't want to disturb the neighbors with a loud compressor. Nothing from the dipstick tube, so rings seem to be OK. Nothing from the intake manifold either. I did seem to hear and feel some air coming from the exhaust. I want to up the air pressure to 120psi tomorrow and perform the check to verify. It seems like the exhaust valve could be bent or broken on #2. While performing the compression test, I covered the spark plug hole on #2 to make sure 0 was correct. I noticed it was sucking in through the spark plug hole fairly well, but hardly any air was pushed out during the compression stroke.
With the compression of the other cylinders, would it be worthwhile to pull the head off and have it repaired? No milkshake in the oil, so I think the heads and head gaskets are good. I'll have to inspect the bore on #2 to make sure nothing scored it. I was considering swapping to a 4.0L as they typically run $300-500 from the junkyards, but an engine swap is a bit more of an undertaking and this is just a daily driver.
I'm thinking I'll repair the head, put my JBA headers on finally, install the free-floating rocker shaft spacers, and port the intake manifold. It would probably be a good time to have the injectors cleaned too.
Are there any upgraded valve springs for the 2.9L? Should I have the other head inspected as well? It's going to be torn apart down to the head anyway.
What about head bolts? Are they re-useable?
I pulled the plugs and every single one of them were black, except #2. The previous owner replaced all of the plugs when it developed the miss, so they were not in but maybe a week. The one he pulled out of #2 when he changed plugs looked bad, really bad. I couldn't tell from the image if it were damaged or just horribly oil fouled. So back to the plugs I pulled out. #2 smelled like gasoline. I changed all of the plugs and found the vacuum hose unplugged from the fuel pressure regulator. I figured it was just dumping a bunch of fuel in. Not the case, still a dead cylinder.
Time for a compression test...
The engine was run idle for about 5-10 minutes to get a little heat into the engine. Today was in the 80s, so it wasn't terribly cold. I propped the throttle open and let the engine rotate until pressure stopped increasing. This was probably about 10 revolutions.
#1 = 190psi
#2 = 0
#3 = 190psi
#4 = 185psi
#5 = 185psi
#6 = 185psi
Obviously a problem with #2. Other than the obvious, how do the rest of the numbers look? They are remarkably even across the board, which I guess confirms the engine was rebuilt at some point in it's life. The chassis has 300K on it now. What is the typical compression numbers from a stock 2.9L in good health?
There was a slight tick coming from the top end on the left bank when the engine was running. I figured maybe a broken valve spring or rocker issue. I pulled the valve cover and everything looks normal. I rotated the engine and nothing out of the ordinary.
So I connected the air hose to #2 and took a listen. I only had about 80 PSI available to me as it was past 10PM and I didn't want to disturb the neighbors with a loud compressor. Nothing from the dipstick tube, so rings seem to be OK. Nothing from the intake manifold either. I did seem to hear and feel some air coming from the exhaust. I want to up the air pressure to 120psi tomorrow and perform the check to verify. It seems like the exhaust valve could be bent or broken on #2. While performing the compression test, I covered the spark plug hole on #2 to make sure 0 was correct. I noticed it was sucking in through the spark plug hole fairly well, but hardly any air was pushed out during the compression stroke.
With the compression of the other cylinders, would it be worthwhile to pull the head off and have it repaired? No milkshake in the oil, so I think the heads and head gaskets are good. I'll have to inspect the bore on #2 to make sure nothing scored it. I was considering swapping to a 4.0L as they typically run $300-500 from the junkyards, but an engine swap is a bit more of an undertaking and this is just a daily driver.
I'm thinking I'll repair the head, put my JBA headers on finally, install the free-floating rocker shaft spacers, and port the intake manifold. It would probably be a good time to have the injectors cleaned too.
Are there any upgraded valve springs for the 2.9L? Should I have the other head inspected as well? It's going to be torn apart down to the head anyway.
What about head bolts? Are they re-useable?