No Compression On #5 Cylinder

[Hypnotic818]

So finally got my car back together after changing head gaskets. Didn't do a compression test first so I put the heads on and everything and did a compression test and I'm getting less than 100 on every cylinder and #5 gets no compression on wet or dry test. These are stock heads with Ford Racing push rods since one of the push rods on #5 cylinder was bent.

Any ideas if I need new heads or valves or something? I'm at a loss :/

Any help is much appreciated!

 

[Hypnotic818]

BUMP

I've been doing a lot of research and so far I'm thinking either a timing chain or the valves on my heads could be causing this.

With the timing chain they said if jumps teeth it could cause low to no compression on the cylinders? I know that my car ran like crap when I got it running. It had major loss of power, misfiring, timing kept jumping, and rattling noises. Which all of that points to the timing chain from what I've read. But I also read that the valves could be getting stuck open, they aren't seating correctly or the valves are burnt. So I'm trying to figure out which one would cause this to be happening. I don't wanna buy new heads or get my stock ones machined just for it to not fix the problem :/

 

[jozsefsz]

A leakdown test can help you determine what's happening without disassembling or buying new parts. The zero pressure on cylinder 5 with a previously bent pushrod tells me there's mechanical damage at least there. Timing chain might help explain the other cylinders, that's tough to diagnose but may be worth changing if your engine is high-mileage. The rattling, misfiring might point to that too. Hopefully it's not worse - a wiped cam or other issues from coolant in the oil (I imagine there was some as the head gasket needed changing).

 

[Hypnotic818]

A leakdown test can help you determine what's happening without disassembling or buying new parts. The zero pressure on cylinder 5 with a previously bent pushrod tells me there's mechanical damage at least there. Timing chain might help explain the other cylinders, that's tough to diagnose but may be worth changing if your engine is high-mileage. The rattling, misfiring might point to that too. Hopefully it's not worse - a wiped cam or other issues from coolant in the oil (I imagine there was some as the head gasket needed changing).

I'll do a leakdown test and see what I can figure out with that. I'm thinking the heads either need to be machined or I should just get new ones. Right now I'm getting down to the timing chain to check for a jump tooth or slack or anything. It does have over 100k miles on it so I'm guessing that would be causing the low compression and stuff.

I hope its nothing worse than needing heads. I live in an apartment so getting to the cam or getting a new engine is gonna be a pain the butt lol.

 

[a91what]

You would never jump a tooth on a double roller timing chain. I just don't see that happening. Most likely a bent valve

 

[Hypnotic818]

You would never jump a tooth on a double roller timing chain. I just don't see that happening. Most likely a bent valve

Should I check the chain anyways for slack or something? My car does struggle to hold base timing. About once a week or every couple weeks I have to redo the base timing. Also should I get my heads machined with new valves and stuff or should I get a pair of GT40ps? I have the correct headers for it and it'll match my GT40 intake.

 

[a91what]

@A5literMan @hoopty5.0 @jrichker
Thoughts?

 

[A5literMan]

Your base timing changes? Jumps around? Initially a bent pushrod/ valve? And issues on #5 cyl holding pressure...leans me to thinking your cam timing is off. How did you mess the pushrod up in the first place? It definitely sounds like a mechanical issue involving. I've never had a chain "slip" a tooth but have seen(on a previous thread/posting-don't remember details) where the cam thrust bearing went bad and caused similiar issues. Is your cam/chain the stock units?

 

[Hypnotic818]

Your base timing changes? Jumps around? Initially a bent pushrod/ valve? And issues on #5 cyl holding pressure...leans me to thinking your cam timing is off. How did you mess the pushrod up in the first place? It definitely sounds like a mechanical issue involving. I've never had a chain "slip" a tooth but have seen(on a previous thread/posting-don't remember details) where the cam thrust bearing went bad and caused similiar issues. Is your cam/chain the stock units?

Yeah it jumps around. I'll set it at 10 and within a week or 2 it goes up or down to the point where it takes the maybe 5 secs or a little longer for the car to catch when starting. On cylinder #5 one of the pushrods was bent. I bought it that way but my dad thought at first thought it was the headers since the previous owner never torqued them. I had to keep re tightening 3 or 4 of the bolts every week till I got a torque bar small enough to get in there. And the cam and chain are both stock as far as I know. I bought the car stock with BBK shorties and I added a GT40 intake a couple months ago.

EDIT: I'm not sure if this will help any but every so often when I put the car from R to D it'll stall and vice versa.

 

[90sickfox]

At an apartment your issues are really hard to diag.

The number 5 cylinder could be checked by hooking an air hose up to the hose for the compression check tool. Rotate the engine ( by hand ) until number 5 is bottom dead center right before the compression stroke. If you hear air out of the intake, or exhaust, then crank the engine around slowly back and forth.

If you can still hear air blowing through the intake or exhaust then the valve is bad. If you hear it coming out of the oil filler neck......then its rings or piston. If it blows air out of the radiator....then it's a blown head gasket or cracked block or head.

*** warning ***

If you have the motor at top dead center ( instead of at the bottom ) the motor can move. You'd be surprised how fast air can rotate an engine.

 

[Hypnotic818]

At an apartment your issues are really hard to diag.

The number 5 cylinder could be checked by hooking an air hose up to the hose for the compression check tool. Rotate the engine ( by hand ) until number 5 is bottom dead center right before the compression stroke. If you hear air out of the intake, or exhaust, then crank the engine around slowly back and forth.

If you can still hear air blowing through the intake or exhaust then the valve is bad. If you hear it coming out of the oil filler neck......then its rings or piston. If it blows air out of the radiator....then it's a blown head gasket or cracked block or head.

*** warning ***

If you have the motor at top dead center ( instead of at the bottom ) the motor can move. You'd be surprised how fast air can rotate an engine.

Sorry for the late reply! I had to wait for my dad to get home with the semi truck to use that as a compressor lol and work has been hell. But we did the compressor test and there was nothing. We couldn't hear anywhere at all. So I pulled the heads again. To find the driver side cylinders were full of water. Like a gasket broke again. But I checked the gasket and there was nothing wrong it at all. But the lower intake wasn't seated correctly I think due to there being rust on the front ports of the head and the back port of the head.

So do you guys think the piston rings are good since the water was still in there? I wasn't seeing any air bubbles or anything that would tell me the rings are broken. And also do you guys got any ideas how the water got in there? I know for sure we seated the head gaskets correctly but there was two spots that were bent where bolts go. So maybe that's how it got in?

I checked the driver side head and all the valves have like bumps around the edges. Like if you run your finger across every valve is lifted up. I'm not to sure if that's supposed to be like that or not.

Thanks for the help so far! You guys have been a lot of help Again sorry for the late reply

 

[90sickfox]

Sorry for the late reply! I had to wait for my dad to get home with the semi truck to use that as a compressor lol and work has been hell. But we did the compressor test and there was nothing. We couldn't hear anywhere at all. So I pulled the heads again. To find the driver side cylinders were full of water. Like a gasket broke again. But I checked the gasket and there was nothing wrong it at all. But the lower intake wasn't seated correctly I think due to there being rust on the front ports of the head and the back port of the head.

So do you guys think the piston rings are good since the water was still in there? I wasn't seeing any air bubbles or anything that would tell me the rings are broken. And also do you guys got any ideas how the water got in there? I know for sure we seated the head gaskets correctly but there was two spots that were bent where bolts go. So maybe that's how it got in?

I checked the driver side head and all the valves have like bumps around the edges. Like if you run your finger across every valve is lifted up. I'm not to sure if that's supposed to be like that or not.

Thanks for the help so far! You guys have been a lot of help Again sorry for the late reply

Now that the heads ate off you can turn them upside down and pour water on the valves. The water should pool up and stay there if the valves are sealing. You could also take a flashlight and shine it in the intake and exhaust ports.

You can also order a machinist's straight edge from amazon. You can use that to make sure the head and block surface is flat.

 

[Hypnotic818]

Now that the heads ate off you can turn them upside down and pour water on the valves. The water should pool up and stay there if the valves are sealing. You could also take a flashlight and shine it in the intake and exhaust ports.

You can also order a machinist's straight edge from amazon. You can use that to make sure the head and block surface is flat.

I was gonna do the water trick but there is a hole behind the the valves. Its in a spot where I can't really make a pool of water for them. And I did look inside the exhaust ports at the exhaust valves. I don't know what they are supposed to look like. I can upload pics if that would help out.

I'm gonna order a straight edge today but I have no idea how I check if the head and block are flat. Like do I just it down and check the numbers or something? Or do I move it around or something lol?

 

[90sickfox]

No light should shine past the valves...water is pit in the chamber with a spark plug installed ( head up side down ). With the flat bar measure across the corners in an x pattern and front to back.

At this point you may want to send the heads for checking at a machine shop. Just to clean and check them isn't expensive.

That water jacket, at the front and rear, shouldn't have put water in the cylinders.

 

[Hypnotic818]

No light should shine past the valves...water is pit in the chamber with a spark plug installed ( head up side down ). With the flat bar measure across the corners in an x pattern and front to back.

At this point you may want to send the heads for checking at a machine shop. Just to clean and check them isn't expensive.

That water jacket, at the front and rear, shouldn't have put water in the cylinders.

I did the water test. When I put the water in no bubbles nothing. But right when I put air into the holes they started bubbling on different spots of each valve. I'm thinking the valves aren't seating correctly and that I didn't put the lower intake on correctly

I was gonna take them to a machine shop to be checked out but I'm also trying to determine from at home if they are bad so I can just order GT40s lol

 

[90sickfox]

I did the water test. When I put the water in no bubbles nothing. But right when I put air into the holes they started bubbling on different spots of each valve. I'm thinking the valves aren't seating correctly and that I didn't put the lower intake on correctly

I was gonna take them to a machine shop to be checked out but I'm also trying to determine from at home if they are bad so I can just order GT40s lol

Why not just get gt40 heads ? Might as well....the motor is apart anyway [emoji106]

 

[Hypnotic818]

Why not just get gt40 heads ? Might as well....the motor is apart anyway [emoji106]

I wanna so bad but I don't want it to not fix my problem

 

[a91what]

I wanna so bad but I don't want it to not fix my problem

Just have a machine shop check your heads out. If they determine that they need a full rebuild then score a set of heads off an explorer and have those rebuild instead

 

[jozsefsz]

If those pistons hydro-locked from the pooled water the valves might well be bent up. It's not hard to remove them, inspect them, and lap them by hand to see if you can get them to seat properly. As it previously damaged a pushrod it's reasonable to assume the whole valvetrain needs inspection. If the lower intake was improperly installed, that could absolutely have caused the water to enter the combusion chambers.

 

[Hypnotic818]

Just have a machine shop check your heads out. If they determine that they need a full rebuild then score a set of heads off an explorer and have those rebuild instead

Yeah I'm probably gonna take them to my local machine shop to get checked out.

If those pistons hydro-locked from the pooled water the valves might well be bent up. It's not hard to remove them, inspect them, and lap them by hand to see if you can get them to seat properly. As it previously damaged a pushrod it's reasonable to assume the whole valvetrain needs inspection. If the lower intake was improperly installed, that could absolutely have caused the water to enter the combusion chambers.

I removed the ones on cylinder #5 and they aren't bent or anything. They look burnt or something. They have a white residue all over them. But I've ran the motor with the new pushrods and none of them are bent or anything. I think the previous owner over torqued them. When I pulled rocker arms I was having to pull hard to loosen the bolts :|. I know the lower intake wasn't on right because like I said above the front and back ports had rust in them like they weren't being used at all.