454 gen v

[PlayDate]

If you could shoot a few pictures down the intake and exhaust ports on the heads.....that will show the condition of the valve seals.

Based on what I see.....almost all the combustion chambers look like oil is getting in. My money is on the valve seals but once you clean up the cylinders.....you can see how the cylinder walls look.

 

[Saverio]

I felt them the walls were very slippery and smooth no ridges

 

[Saverio]

 

[Saverio]

View attachment 62102 View attachment 62102 View attachment 62103 View attachment 62104 View attachment 62105

 

[PlayDate]

Thanks for the pictures.

The exhaust port on the left in this picture definitely has what looks like to be oil in it. The pictures of the head gaskets just look old. I'm not sure they tell a story other than carbon beyond the compression ring would indicate poor sealing and a loss of cylinder pressure. Getting the heads done will really help. I would also rebuild the carb at the same time. It seems as though it is running a bit rich.

You do want to clean up the cylinders. Debris from pulling the heads will find its way in between the piston and the cylinder wall. Most debris will get cooked but metal from the head gasket can score the cylinder walls. How do the cylinder walls look?

 

[Saverio]

Thanks. Play date

The carb is a Weber. It was just replaced when I got the boat has less than 80 hours on it.

 

[Saverio]

Well I started to put back together and it just doesn’t look right???

 

[310sundancer]

Does gaskets to not look right. What brand are they?

 

[ttmott]

View attachment 62637 View attachment 62635 View attachment 62635 View attachment 62634 Well I started to put back together and it just doesn’t look right???

Those look right; Make sure the right gasket P/N for the coolant passages.

 

[Saverio]

Felpro

 

[techmitch]

Felpro

Glad to see you got "Marine" gaskets. Not a GM guy, but how do they match up to the heads?

 

[PlayDate]

The easiest way is to match them to the old gaskets if you still have them. The earlier head gasket pictures have the same passages.

 

[techmitch]

The easiest way is to match them to the old gaskets if you still have them. The earlier head gasket pictures have the same passages.

I agree, but we don't know if it's ever been apart before and you never know if the correct gaskets were used. I think I have seen that gasket/head/combustion chamber pattern on GM's before so he is probably ok, but always good to check the mating surfaces.

 

[Saverio]

I’m just concerned on how the cylinders holes are not round but like oval.

 

[techmitch]

I’m just concerned on how the cylinders holes are not round but like oval.

If the sealing rings on the gaskets match the cylinder heads you should be good. Pics?

 

[Saverio]

If the sealing rings on the gaskets match the cylinder heads you should be good. Pics?

This what doesn’t seem right.

 

[ttmott]

This what doesn’t seem right.

Normal gasket for standard rebuild. Relief for cylinder notching / valve clearance / gas flow. Some open chamber heads require the tops of the cylinders to be notched or "eyebrowed" for valve clearance; some notch the cylinders to match the head chamber for better flow. Looks like your cylinder heads are oval port so they appear to be small valve open chamber heads. Round cylinder gaskets can be obtained but they are specialty copper /MLS.

 

[Saverio]

I just looked at the pictures on page one and it does look like my heads have that notch, ok I feel some what better but if you look at my old gaskets they really don't look like that. the shop that rebuilt them said the gaskets were blown due to u can see combustion on both side of the gaskets he thinks it was blowing back and forth

 

[ttmott]

I just looked at the pictures on page one and it does look like my heads have that notch, ok I feel some what better but if you look at my old gaskets they really don't look like that. the shop that rebuilt them said the gaskets were blown due to u can see combustion on both side of the gaskets he thinks it was blowing back and forth

Gasket burn through is rare in low compression engines and when it does occur usually the coolant gets blown out of the engine due to the high pressure gasses venting into the coolant passages; It appears the block deck or head to block surfaces possibly were not true and/or the clamping force was incorrect or not sequenced correctly. Have the heads checked and if required surfaced. Also have the block deck checked for warpage but significant warpage is rare in these blocks. And, it goes without saying new bolts and washers.

 

[techmitch]

Looking at your heads in post #20 and your old gaskets in post #24 it looks as if you do have the heads with the oval shaped combustion chambers and the old gaskets match your heads and your new gaskets. As Tom said make sure the heads and block checked for flatness. This is imperative!