Hello all. I have what should be a very basic question to ask. I just bought a pair 1967 marine 327 motors. One of these underwent $1200 in work at a shop before it was stored for the last 16 years next to its twin. I took off the heads and found new trw.030 flat tops in the cyls. I pulled the 10 quart cast iron oil pan and found a forged steel crank.Then I was looking at the rods and they look to me like they are installed wrong. I thought that the thicker part of the big end always faced outside towards the crank, and the thinner side went against the other rod. These are all installed with the thicker parts touching eachother. also the #2 rod has a #8 cap on it, all the others are not marked, but it looks to me as thou the rods were resized so I'm not sure that that makes a difference. I took off one of the caps and found what looks like an oil spurt groove and hole machined into it but the bearing does not have the cut out notch in it to let oil get to it. I may be nuts, but I dont think something is rite with this. I will post some pictures if I can figure out your posting protocall.
If they are a pair for the same boat one will rotate the opposite of the other (reverse ground camshaft) Most marine engines have marine camshafts designed for a specific rpm range. You should check both engines very carefully to determine exactly what you have. KK
Thank you. I understand. This is the reverse rotation motor that I am looking at now. But I dont think that changes how the the rods are installed in the block.
It has been a long time since I have put a sbc together and I have never done a reverse rotation marine motor so that is why I am hoping to get set straight. Thanks for any help.
On a right hand rotation [opposite automotive ] pistons are mounted notch toward the flywheel end , rods mount in their normal manner .
If I were you I would have those blocks pressure checked.Once a marine engine has been run in salt water if it has a raw water cooling system the block starts to rust internally and does not stop.
Thanks justold. These pistons are all installed with the f mark towards the front ( water pump/cam gear end) I think that the rods were pressed on backwords in relationship to to the pistons. This motor was run only long enough to set valve lash, then the original owner got sick(cancer or somthing) the boat was scraped and the other motor pulled out and they have sat for the last 16 years. A time capsul of sorts. There has to be a sbc builder on here that can look at those pictures and tell if they are installed rite or wrong.
DDDeny. I have a pic of the windage tray and oil pump with the extended pick up but not of the pan. I will take one and get it on here for you. I also have all of the other cast iron parts that made this a marine moter x2.
I was told that the motors came from a 36 foot fishing boat that spent its life on the great lakes,(fresh water) The block looks clean except for sitting for the past 16 years at a body shop. I have not taken apart the other one yet.
Damn, that engine sure is clean. Never done a marine engine because of the reverse thing. I'd screw it up for sure. Good luck.
Wow, that windage tray is the longest I've ever seen, looks like the front end of it is about ready to break off.
If you look at the rod bearings, they normally are offset towards the center, so there is room for the fillet at the edge of the journal. They sure look backwards here. And the oil hole should point "up", not "down" (ie it should go towards the cam shaft).
If the arrows on the pistons are facing to the front then by removing each rod and piston assembly and turning it so the arrow faces to the rear you will have the rods installed correctly, as well as having the pistons in the bores properly since the major thrust surface has switched sides with the CCW rotation. It looks as though whoever assembled the shortblock was only concerned with the " front " arrows and was not aware the rods and pistons had been assembled for a reverse rotation engine. In addition the crank snout and rear main seals will be different for a reverse rotation engine, there is a very fine helix molded on the seal surface that is opposite the standard (CW) engine. Another thing that needs mentioning is that many modern twin screw boat drives do not require a reverse rotation engine.
I am thinking the same thing squirrel. This motor was put together at a shop not in someones back yard. Never put in service, only long enough to set valve lash. I think there wrong. DDDeny they tray is cracked in the front on both sides and needs to be repaired if it was going to be used again.
Thanks fordors. I am not going to use this in a twin screw boat again. It will be in a boat but it will be installed just like it would be in an old chevy truck, flywheel back,transmission at the back prop at the back.I was only wondering about the thick part of the rods touching each other in stead of fascing out towards the crank.
If I am understanding... The pistons still need to face with the f mark towards the front(water pump end) and the rods all need to be changed to face the other way to use this as you would in any other car.
switch all the pistons/rods from one side of the engine to the other. Leave them pointed the same (to the front) as they are now.
Bearing companies kept the squirt hole in bearings for years but GM quit notching the rod caps. I feel they did it to "cause" problems making work for their service techs by having cams go flat. Just an opinion. Currently all the bearings we use no longer have the split hole but we give the rods a lot more side clearance and don't loose the cams. We are pretty tough on our circle track engines as they spend 20-30 laps between 4800to 7200, corners and straightaways. I'd take both completely a part and check every thing... They sound like a good deal,to me.
In all honesty I don't know much about boats, I based my comment on the major and minor thrust surfaces from my experience with Electro-Motive Diesel engines. But if I understand your comment you want to use this in a single engine boat, wouldn't that require a standard, CW, rotation engine? Your first photo shows a crank gear with a helix angle and that matches the GM two gear drive for the reverse rotation cam. Again, I don't know boats but if you need a CW engine your rods are installed wrong as you believe but then you will also need a different cam and crank gear, a timing chain, camshaft and a starter. Or I'm all wet. Boating pun intended.
Still would pressure check the blocks as straight water with no rust inhibitor was used to cool those motors. I have seen salt water big blocks rust through the bores and the cylinder heads.
Usually NOT many HOURS on --them there boat motors--- so if serviced regularly they stay purty CLEAN.
If boat engines are run with an heat exchanger and antifreeze they live fine. BUT raw water cooling in coastal areas SUCK. Rust and blown head gaskets in 4 to 5 years is my experience with Mercruisers. You need to inspect old boat motors VERY carefully if you are buying them. I would not buy one with raw water cooling period. I would look at an heat exchanger motor if I could take the heads and pan off for a look. 99% of the time the water passages are rusted solid. The engine over heats and blows the head gasket. The cylinders get saltwater in them. The boat is put up for years. Then everything is a solid rusted mess. On TOP of being warped from over heating in the first place.
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