My son helped me get all the exhaust parts off the starboard engine (port engine in a few days)..DAMN they are heavy!!! Risers that I cleaned out last year were in worse shape, so they definitely need replacing. The exhaust manifolds were full of carbon and the coolant passages looked a little gunky. I noticed that the very end of the inside of the exhaust log was a little rusty. Like some moisture had seeped through the riser gasket that I replaced last year. Which may also explain some of the high temps. And in removing the end cap I sheered a bolt off...Not an issue I want to deal with and I really don't want to replace the entire log, so hopefully, I can get it out!!!
Checked out the valves with the exhaust manifolds off..All carboned up except one was oily. First thing I thought was blow by! But I checked my compression records for last year and it was great. Then I realized I saturated the chambers with fogging oil and that valve was open lol.
Going to call a machine shop next town over that a buddy used and drop off the exhaust manifolds to be cleaned down to the bare metal (and remove that sheared bolt). Then bring the Heat Exchangers hopefully to a radiator shop to be boiled out and pressure tested. They do need to be repaired. But coolant side drain plugs are damaged (one was ground out and was sealed with a bolt and 2 rubber washers, and the other is leaking hard). Going to braze on two flanged copper nuts to make the repair and allow for some Zincs to be added. So Hopefully I'll just need to purchase new risers, hoses and hardware/gaskets and I can save all the other parts. Then I will be one step closer to getting another season under my belt!
Ouch... These bolts were rusted into the endcap and no amount of heat/fluid would un-seize this one.
Just my two cents worth but with bolts rusted so bad you cannot get them out, hairline cracks and water intrusion into the engine already I'd go the $1500 and replace everything. I had water in at my valves and ended up with far more in repairs than new manifolds and risers. Manifolds, risers, heads refurbished, starter rebuilt, flywheel.and I got lucky as there was no piston or cylinder damage when I dropped the valve. If it goes it will probably go at the most inopportune time. Mine went on the 3rd of July with a boat full of people for the holiday. Pay now or pay later but pay you will.
I guess I'm gonna be having to pull the intakes and heads to get in there..ug not really what I expected to be doing. And thr very least I'll have to raise the engines to replace the engine bed. I might as well remove them both, get them scrubbed down and repainted and get into the bilge and clean that disgusting mess up and paint that too...
Mike, what is a channel type mount?
At this point...I think at the very least, the engines would have to be lifted to replace that engine bed, and to replace all the mounts and wedges.At this point they are cracked or severely rusted. Wouldn't even be possible to align them this way.
The oily valve may have a bad valve stem seal. Lift the valve cover and check it, Located inside the valve spring and is umbrella shaped. That can be replaced on the engine with the right technique. It involves pressurized air to hold the valve up and a valve spring tool. Replace one? Replace all. Lee
Looks like I found the culprit now that I have all 3 risers separated from the exhaust manifolds. On the one with the rusted exhaust the pic below was the worst, but it's the same issue on the other engine where I found rust inside the exhaust manifold where it meets the riser. Looks like the gaskets failed and allowed coolant into the end of the manifold.
this one was the worst and is fairly obvious. There was a mixture of metal gaskets and copious amounts of orange rtv used and not to mention some of these risers are 25 years old. The risers I attempted to fix last year where I used paper gaskets and black rtv held up real tight.
So the question remains, to I go all in and remove the heads and have them cleaned back up since 4 of the valves aren't in the greatest of shape. The seals seems to be holding since compression tests done at the beginning and and of last season were great. I already know that at a minimum I need to raise the engines to repair the mounts and beds, I might as well go all in with my resto now. lol
Get the heads redone, new manifolds where needed (I would just replace all of them and not mess around), new risers, and you'll still be lots of dollars ahead of new motors.
The manifolds won't need to be replaced. They are originals from 1969, but they are coolant cooled and in amazing shape. At most, when I have the machine shop boil them out, I'll make sure the gasket mating surfaces are perfect. Will save me about $1,000 right there..