454 valve questions

[kschnebly]

Pulled my head on my 454 after having the crankcase fill with water. In the process I ran a compression test and found that the #5 cylinder was 0 psi. All others were goo . The valves is sitting much deeper and the tension on the spring is much less. Did lose the valve seat? If so wouldn't I expect some piston damage?

 

[Scott Danforth]

take the heads into a shop

the rust indicates your cylinder has been wet for some time, which would have caused rust on the seat, which then in turn you ran it for a while and fire-sloted the seat a bit. then you let it sit, the water that continued to come in would rust the seat/valve and you eroded the seat away.

they may not be able to repair that

also, look at your manifolds on that side, I bet the joint where the elbow meets is either bad (rusted away), or the manifold has a crack.

the water in the crank case is the water leaking past the valve and ultimately past the rings.

 

[alldodge]

crankcase fill with water.

With the crankcase filled with water, you may have rust on the crank and cam shaft journal's. If cylinder walls have rust it can damage the rings

 

[kschnebly]

Cylinder walls are clean. Crankcase doesnt seem to be bad. Water was drained same day that it got into the motor. That was 2 seasons ago. Thoughts?

 

[alldodge]

Guess I don't understand the time line

Pulled my head on my 454 after having the crankcase fill with water.

Only one cylinder head shows rust

That was 2 seasons ago

But asking the question now :noidea:

 

[kschnebly]

take the heads into a shop

the rust indicates your cylinder has been wet for some time, which would have caused rust on the seat, which then in turn you ran it for a while and fire-sloted the seat a bit. then you let it sit, the water that continued to come in would rust the seat/valve and you eroded the seat away.

they may not be able to repair that

also, look at your manifolds on that side, I bet the joint where the elbow meets is either bad (rusted away), or the manifold has a crack.

the water in the crank case is the water leaking past the valve and ultimately past the rings.

Thanks, the water is from a cracked intake manifold just under the tstat. I'd like to avoid a total teardown. I'm taking the head in this week to see if its serviceable. Where is the joint your talking about? On the intake or exhaust manifold?

 

[Scott Danforth]

Exhaust

 

[kschnebly]

Guess I don't understand the time line



Only one cylinder head shows rust



But asking the question now :noidea:

Labor day 2016 overheated my motor after hitting a sandbar. Spent the winter 2016/2017 flushing the motor and did a lot of out drive work. Took the boat out spring 2017 and after 30 minutes on the muffs I noticed water in the oil. Boat was put away, bad oil drained, pressure tested water side (failed), performed compression test which showed #5 cylinder was 0.

Started tear down early June 2019 and just got the intake and port side head removed. Seems like the water came from a cracked intake and the 0 compression came from a valve. Now I'm just trying to piece together the best next steps.

 

[kschnebly]

[No message]

 

[Scott Danforth]

bore #5 is rusty

goes hand-in-hand with your bad valve.

your exhaust manifold to elbow joint is leaking or you have a crack.

if this is a salt water boat, going with exhaust rusted thru

the intake manifold failure just happened about the same time.

 

[kschnebly]

I'm going to be smart about it and just do a full teardown of the motor. I hope to have the engine out of the boat by the middle of July. This way I can hone the cylinders, replace the rings, and make sure the crank and the cam aren't pitted. Also lets me check the water jacket for any additional rot. This also will give me a chance to reconfigure my engine compartment layout without having to work around the motor. Since the intake manifold, head and exhaust manifold are off the port side of the motor, can I bolt a lifting plate to the block via the head bolt locations? On the Starboard side I still have the head and exhaust manifold in place. Can I mount a plate to the intake manifold bolt locations? I'd like to avoid the manifold and head removal while in the boat since it is much easier to do it on a stand.

 

[Scott Danforth]

I would get a core motor from a salvage yard for $400 or less and have that rebuilt, then when you pull the bad motor, you spend a few hours swapping a few parts over and install the new motor right away.

as far as lifting, pull the other head and manifold to balance the motor. that 85# chunk of iron head and the 65# chunk of manifold are a lot of weight up high without a similar weight on the other side. the motor will want to twist as you lift it and someone may get injured

 

[kschnebly]

take the heads into a shop



also, look at your manifolds on that side, I bet the joint where the elbow meets is either bad (rusted away), or the manifold has a crack.

Pulled cleaned and tested the port side manifold. It is in fact cracked and when pressurized to 25 psi it gurgle . Add that to my parts list.

 

[Scott Danforth]

starboard side may not be far behind.