Compression Test Readings

[tpenfield]

Were any of the head bolts loose (not fully torqued) when you removed them?

 

[Raggy1071]

To me, some did not break loose as easy as others. But still tight.

 

[tpenfield]

OK . . . a hydrolock can stretch the head bolts, which may act like a blown head gasket.

 

[Lou C]

Before spending more money I’d take a mechanic’s straight edge and measure the block deck surface for flatness (less than .003”). Due to suspicion of a past overheat get the heads checked out by a machine shop. Mine were cracked in the exhaust seats & I just bought a pair of reman 4.3 heads. Heads, gaskets & new head bolts whole works came to only about $750….

 

[stresspoint]

0.60 over . definitely strait edge the engine block to be sure it is in spec,
send the heads and have them re surfaced , because as has been posted , that motor has had an over heat or possibly hydro lock (check riser and manifolds as i mentioned in your other thread)
.
? how did the wet test go on the valve seats and guides.,

FWIW , it sometimes pays to have the shop recondition the heads ratherthan just a resurface , also ,have them crack tested while they are in the machine shop ..

 

[tpenfield]

Generally 060 over is the second rebuild. Maybe this engine is ready to 'retire'

 

[Scott Danforth]

I pulled the heads and here are the gaskets. I do not notice any missing material, but do notice some Dark areas between cylinders.

you have blow-out between cylinders. you lost clamp force along the way.

my guess, the heads were off once prior and someone did not torque correctly, or the motor was overheated.

 

[Scott Danforth]

60 over and an overheat means spending $800 on new blocks

 

[ROY WILLIAMS]

Before spending more money I’d take a mechanic’s straight edge and measure the block deck surface for flatness (less than .003”). Due to suspicion of a past overheat get the heads checked out by a machine shop. Mine were cracked in the exhaust seats & I just bought a pair of reman 4.3 heads. Heads, gaskets & new head bolts whole works came to only about $750….

new head bolts !!!! good ..

 

[Lou C]

Before spending more money I’d take a mechanic’s straight edge and measure the block deck surface for flatness (less than .003”). Due to suspicion of a past overheat get the heads checked out by a machine shop. Mine were cracked in the exhaust seats & I just bought a pair of reman 4.3 heads. Heads, gaskets & new head bolts whole works came to only about $750….

new head bolts !!!! good ..

I used ARP bolts & used a thread chaser to clean the cyl head bolt threads in the block.

 

[Raggy1071]

Thanks for your comments everyone. I am taking the heads to machine shop to be inspected and have any needed work done on them. I do not have a machinist straight edge but run a Long Carpenters square across block this evening and it seemed good, I will see about getting machinist straight edge. I will probably get new head bolts too. I did not spend much on this boat so I am not surprised by what I have found, I was told it needed head gaskets when I bought it. I wanted a mechanics special so I could get into boating with low cost, run next season , see if boating is for me and then spend the money on a nicer turn key boat or sell off this one for cheap with no worries if I don't like boating. Yes I could just rented a boat all next season, but I like to tinker on stuff

 

[Raggy1071]

0.60 over . definitely strait edge the engine block to be sure it is in spec,
send the heads and have them re surfaced , because as has been posted , that motor has had an over heat or possibly hydro lock (check riser and manifolds as i mentioned in your other thread)
.
? how did the wet test go on the valve seats and guides.,

FWIW , it sometimes pays to have the shop recondition the heads ratherthan just a resurface , also ,have them crack tested while they are in the machine shop ..

Thanks for the advice, I will check the riser and manifolds also, at minimum will put all new gaskets.

 

[Scott06]

Thanks for your comments everyone. I am taking the heads to machine shop to be inspected and have any needed work done on them. I do not have a machinist straight edge but run a Long Carpenters square across block this evening and it seemed good, I will see about getting machinist straight edge. I will probably get new head bolts too. I did not spend much on this boat so I am not surprised by what I have found, I was told it needed head gaskets when I bought it. I wanted a mechanics special so I could get into boating with low cost, run next season , see if boating is for me and then spend the money on a nicer turn key boat or sell off this one for cheap with no worries if I don't like boating. Yes I could just rented a boat all next season, but I like to tinker on stuff

at least someone was honest about what was wrong with it. Just make sure the deck and head are flat before you go back in. With a machinist straight edge. Reason being as mentioned above looks like someone was in there doing head gaskets already… prob overheated the **** out of it replaced gaskets and it didnt hold.…

now is the time for complete tear down if needed or get a junkyard 5.7, you just want it to work next spring …

i did the same thing seven years back. Bought one with a cracked block. I spent the money for a new base engine been trouble free and worth the extra $ from my perspective

 

[alldodge]

Carpenters square

Nothing wrong with a carpenters square, works just fine. No need for specific edge so long as its not damaged