Hi all,
My first post, so here goes.
My experience with engines etc is a back yard mechanic. Very mechanically inclined. I have swapped out many engines, cars, trucks and boats. Lots of my own trouble shooting, replaced or swapped out intakes, heads, cams. But I have never taken the time to do a full rebuild or even dismantle crank, rods, pistons etc. So bear with me. And there is no offense taken, so please school me.
I'm in the middle of re-powering my boat, I bought a used engine that had about 80hrs on it when it was pulled from the owners boat, then it sat in storage for about two years. Some back story on this motor, I bought this complete from a guy that has had a marine surplus business for the last 35 yrs. Him and his son built the engine for there personal boat and decided to part out the boat. So the engine had about 60-80 hrs then sat in storage for a couple years and its obvious they did not prep it for storage. I have tried to get as much info as I could on the build but his aging memory seems to be failing him. So I have had to do some research on the engine. He says they put about 11k into this thing.
The engine specs are: 350 chevy, bored .060 over, I'm assuming 400 crank, heads are World Products S/R TORQUER Iron 202 Heads, but I can't tell if the chamber size is 67 or 76cc, they offer both in this head. (see attached images for casting id's and specs). Edlebrock performer rpm cam and intake. And a closed cooling system, (raw water dumps out risers).
I brought the engine home and started to check compression, engine would not turn over, almost like the pistons were froze. I managed to take a screw driver and move the flywheel back and forth a bit then all started moving freely. So I started checking compression, some cylinders went straight to 170 and some wouldn't budge past 60, but after a couple hours of checking all cylinders over and over again it seemed the compression slowly build up, but some never made it past 120. And during the process of turning over the engine with all plugs out, some debris that looked like rust would shoot out of a few cylinders. So I pulled the exhaust manifolds and there was lots of flaking rusting debris falling out of the ports. Then I decided to pull the heads and cylinders # 2 and 6 had so much build-up of dirt, rust, not really sure. And once I scraped the pistons clean I noticed the heavy pitting. All the other pistons show normal carbon build-up but #5 shows a bit of rust looking build-up. See the attached images.
1. What was the cause of the engine not initially turning over?
2. What would cause the compression to slowly rise in some cylinders over a period of an hour of back and forth checking (while letting the started cool down)?
3. What is the cause of the pitting, detonation possibly, or could there have been salt water sitting in the cylindera during storage that could have caused the build-up and pitting? And are the pitted pistons ok to use or should they be replaced?
Also the the engine has a closed cooling system including the manifolds, risers are raw water. So if the problem is water intrusion, could it be from sucking in raw water through exhaust? Seems to be the only explanation if there was water in the cylinders. I would assume that any coolant sitting in the cylinders would not do that kind of damage/corrosion to the piston as opposed to salt water.
So I need figure out if I can salvage this motor. If this engine has such low hours, can I use the short block (they used a good block 3970010) just as it sits and just replace pistons and rings. I guess I would have to find out what crank, rods, etc it has and condition (assuming its all good with such low hours). And I'm also assuming I would have to replace cam (as I mentioned before it was built with the performer rpm cam and intake) package.
I tried to give as much info as possible. I'm looking for some guidance and direction. I appreciate your time.
Thanks,
Jim
My first post, so here goes.
My experience with engines etc is a back yard mechanic. Very mechanically inclined. I have swapped out many engines, cars, trucks and boats. Lots of my own trouble shooting, replaced or swapped out intakes, heads, cams. But I have never taken the time to do a full rebuild or even dismantle crank, rods, pistons etc. So bear with me. And there is no offense taken, so please school me.
I'm in the middle of re-powering my boat, I bought a used engine that had about 80hrs on it when it was pulled from the owners boat, then it sat in storage for about two years. Some back story on this motor, I bought this complete from a guy that has had a marine surplus business for the last 35 yrs. Him and his son built the engine for there personal boat and decided to part out the boat. So the engine had about 60-80 hrs then sat in storage for a couple years and its obvious they did not prep it for storage. I have tried to get as much info as I could on the build but his aging memory seems to be failing him. So I have had to do some research on the engine. He says they put about 11k into this thing.
The engine specs are: 350 chevy, bored .060 over, I'm assuming 400 crank, heads are World Products S/R TORQUER Iron 202 Heads, but I can't tell if the chamber size is 67 or 76cc, they offer both in this head. (see attached images for casting id's and specs). Edlebrock performer rpm cam and intake. And a closed cooling system, (raw water dumps out risers).
I brought the engine home and started to check compression, engine would not turn over, almost like the pistons were froze. I managed to take a screw driver and move the flywheel back and forth a bit then all started moving freely. So I started checking compression, some cylinders went straight to 170 and some wouldn't budge past 60, but after a couple hours of checking all cylinders over and over again it seemed the compression slowly build up, but some never made it past 120. And during the process of turning over the engine with all plugs out, some debris that looked like rust would shoot out of a few cylinders. So I pulled the exhaust manifolds and there was lots of flaking rusting debris falling out of the ports. Then I decided to pull the heads and cylinders # 2 and 6 had so much build-up of dirt, rust, not really sure. And once I scraped the pistons clean I noticed the heavy pitting. All the other pistons show normal carbon build-up but #5 shows a bit of rust looking build-up. See the attached images.
1. What was the cause of the engine not initially turning over?
2. What would cause the compression to slowly rise in some cylinders over a period of an hour of back and forth checking (while letting the started cool down)?
3. What is the cause of the pitting, detonation possibly, or could there have been salt water sitting in the cylindera during storage that could have caused the build-up and pitting? And are the pitted pistons ok to use or should they be replaced?
Also the the engine has a closed cooling system including the manifolds, risers are raw water. So if the problem is water intrusion, could it be from sucking in raw water through exhaust? Seems to be the only explanation if there was water in the cylinders. I would assume that any coolant sitting in the cylinders would not do that kind of damage/corrosion to the piston as opposed to salt water.
So I need figure out if I can salvage this motor. If this engine has such low hours, can I use the short block (they used a good block 3970010) just as it sits and just replace pistons and rings. I guess I would have to find out what crank, rods, etc it has and condition (assuming its all good with such low hours). And I'm also assuming I would have to replace cam (as I mentioned before it was built with the performer rpm cam and intake) package.
I tried to give as much info as possible. I'm looking for some guidance and direction. I appreciate your time.
Thanks,
Jim
