351w oil pump |
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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Posted: July-31-2024 at 5:37pm |
Hello everyone, can anyone tell me if rotation matters when replacing an oil pump on a 351w?
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Billy
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11069 |
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The same pump is used no matter which way the engine rotates
The oil pump in both normal rotation and reverse rotation engines turns counter clockwise because of the cut of the cam gear and distributor gear. A Melling M83 or something that cross references to it, is a good stock replacement pump for your engine. A Melling HV83 is a bad replacement for your engine because it's a taller pump that hits the oil pan and keeps the pan from seating on the block which makes for an oily mess You're just fine with a stock volume pump
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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Thanks Keno, I understand now. I was restoring a '78 ski nautique and had the RR engine rebuilt when I found a beautiful '91 sport for 8k. The engine in the sport ran great for a couple hours, but then it stalled and hydro locked. I pulled the heads and one was cracked. Since I had not installed the rebuilt RR engine in the 78, I'm using it in the sport. I'm replacing the cam because the sport is LR with a new upgraded 1:23;1 transmission. That's why I was concerned about the pump. I'll rebuild the leftover engine when I can afford it. Can you think of anything else I should do while I have both engines on stands?
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Billy
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3738 |
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A set of the later GT40 heads can help add a lot of power if it is in the budget.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11069 |
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The first thing you should do is look at the rebuilt 78 engine which if it's the original block will have a 2 piece rear main seal and then look at the 91 which would have a 1 piece rear main seal. If you reverse the rotation of the 78 to make it a normal rotation engine, you're gonna have a rear main seal leak. The 78 uses a crankshaft that has oil control wick lines (AKA helix lines) on the crankshaft in the area of the rear main seal and the lines are backwards on a reverse rotation engine. Here's a picture of the lines. This one is Reverse Rotation This means that instead of helping to keep oil in the engine, the backwards wick lines will help oil leak past the seal if you turn the engine the opposite of what it was meant to turn. It's not just a minor leak either. You'd have to put in a normal rotation crankshaft built for the 2 piece seal or get the lines removed by your machine shop. The crankshafts won't interchange between the earlier 2 piece rear main seal engines and a later 1 piece rear main seal engine without some serious machine work either. The front seal isn't as critical, and it can still be bought for either rotation direction. It has the oil control lines in the seal running on a smooth sealing surface on the harmonic balancer. You might say that nothing is as easy as you'd like it to be. Numerous people here on CCF have run into this rear main seal issue on a rebuild or engine replacement when changing engine rotation.. You mention that you have a new heavy duty 1.23 to 1 transmission for the sport. Is it the later, new and improved PCM 80A or the original style PCM40A? There's a reason I'm asking, so make sure you tell what you have |
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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The mechanic who rebuilt it had a pair of GT40 steel heads on hand and used them in the rebuild.
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Billy
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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The transmission is the 80A and it looks brand new. They used a piece of rubber on top to protect the muffler which seems to work. I haven't pulled the engine block out of the sport yet. I will be pulling the trans out of the way to install a new shaft that came with the boat. Should I use the new plastic cutlass bearings from nautique parts online? The original 78 block had a pin hole in one of the cylinders so my mechanic used another block and I have not pulled the oil pan yet. I do most of the work at night because of the heat in Orlando and I just turned 68. I'm also taking pictures as I go and soon as I pull the oil pan and the engine out of the sport I'll figure out how to add a couple pictures. I really do appreciate your time and expert advice. The sport came with a 2015 boatmate trailer with vault bearings and it sits a little higher. I have a 2 ton cherry picker that has some reach, but it's going to take a minute to get that engine out safely. I will let you know my progress tomorrow.
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Billy
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3738 |
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With the complications of using your RR engine in this boat you might consider just installing the nice heads off the 78 on your 91 and go boating?
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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That was my first thought, but when I dropped the heads off from the sport my mechanic all I need is a cam and the sport would have a new engine. Head gasket and cracked head, it obviously overheated. It had 60 psi oil pressure at idle. The compression test w/oil was 150 across the port side and starboard was 100, 50, 100, 100. I bought a melling marine #24107 cam for the 78 and an edelbrock 2181 intake cause both intakes were rusted pretty bad. I guess I'm still on the fence trying to make an informed decision. That's why I brought it here. I do appreciate all the help and information.
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Billy
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11069 |
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Just to make sure that I understand this whole thing, it sounds like the 78 engine is complete right now and is Reverse Rotation and you went and bought a Melling 24107 normal rotation cam to put into it to make it a normal rotation engine.
You'll need some new unused lifters to go with the new cam. Maybe the 78 has never been run and it has new lifters, otherwise if it has been run, then the used lifters and the new cam aren't a good combination The normal rotation starter from the 90 and the normal rotation rotation distributor from the 90 would swap over to go with the cam swap The PCM 80A only works with a Normal Rotation engine, so you're good there. You can't use it behind a Reverse Rotation engine and do a prop swap unfortunately, otherwise things would be a lot easier. So, you need to figure out the seal configuration situation and get that right in order to prevent a seal leak. The 90 engine sounds like it was overheated and needs new heads as a minimum and maybe a lot more work that you're not sure about yet. That all sound about right?
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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Yes, that is all correct and there is still some lingering moisture in the crankcase of the 91 after 4 oil changes. That's why I decided to pull the engine in the 91. I pulled the oil pan from the 78 and looks like I need to remove the rear main cap to view crankshaft lines. I'll do that and report what I see.
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Billy
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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Also, the 78 engine has not been started so I should be able to use the same lifters etc.
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Billy
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3738 |
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Most engine overheats only damage the heads and head gaskets. Unless someone really got stupid and heated the block till it scuffed pistons, if you see any dark verticle marks on the thrust side of the cylinders the block needs a rebuild. If the cylinders are clean with good cross hatch still showing it should be good.
In extreme overheats I have seen the cam bearings melt but in 30 years I only saw that twice. In one case a customer fired up a brand new engine, his phone rang, in those days you had to run to the office to answer. The engine ran till it froze up. When he came back off his phone call he realized he fired up the brand new engine without filling the radiator. He was on the phone about 30 minutes. The brand new Paint on the engine had burned black from heat. It happens and things get hot and melt. I have seen new starts without Oil installed also but they stop and lock up much faster. Most overheats kill the head gaskets first, in many cases that is where the damage stops. After the overheat with a crushed head gasket you will lose compression in cylinders and get coolant into the chamber or the oil possibly.
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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The more I look at it (91) the more I realize it needs a rebuild. Also, when I changed the plugs, the #2 spark plug was missing some of the L on top. The top of #2 piston is pitted badly. The heads are ready for pick up so at least that's out of the way. I tried to save it, but it just wasn't in the cards. I will be replacing the prop shaft because of rust and I have one still in the crate that came with the boat. Those new $57.00 plastic strut bearings look like the way to go. Have you heard anything about them? I've had the 78 ski nautique since 05 and the engine finally wore out. I'll keep the sport and sell the 78, but I want it to be right so the next owner won't have to go through what I've been dealing with.
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Billy
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3738 |
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I installed the plastic strut bearings in my 95, no issues but I only have 125 hours on them so far. There is very little drag in the shaft with the plastic bushings. I think they are made of Delryn same stuff used in human hip replacements and in ball joints on cars.
If you have pitting on the piston and the missing electrode on the spark plug that cylinder was detonating. Usually caused by a lean burn/ High Combustion heat. On modern engines one cylinder being damaged usually means one injector was not working proper. On the old carb engines one cylinder detonating was either an air leak leaning out that one cylinder or plug wires routed wrong or mis firing, maybe cross firing from one plug wire to another. Detonation creates huge cylinder pressures and can blow out head gaskets. Figure that out before starting your new engine or the problem may go from the old engine to the new one. |
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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Thanks for the info on the cutlass bearings. I will give them a try with a new shaft.
I went to Corpus Christy tx from Orlando to pick up this sport nautique. I gave it a once over and let it run in the driveway for about 15 minutes. No leaks, good oil pressure, 145°. Went to the lake and eased it around till warm up. Pushing the throttle at higher rpm produced a backfire. I found #6 and #8 plug wires switched. I fixed that with new wires and plugs. That's when I found #2 cylinder spark plug damaged. Back to the lake and it pulled pretty good until I brought it to idle and it stalled. That's when it hydrolocked. Head gasket at #2 crushed. Still not sure what happened, but with the piston pitted and water in the crankcase I've decided to pull it and go with the 78 engine if I can. I'm pulling the rear main cap off the 78 to look for those helix lines tonight. |
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Billy
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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You were right about the helix lines and their direction. Looks like that's the only thing holding me back. Tomorrow I will try to get the engine out of the sport. I want to make sure it's a newer engine and has a 1 piece rear seal b4 I buy another crankshaft or have it machined. If I have it machined, will that require a different set of seals if they even make a seal for that application?
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Billy
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3738 |
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The Reverse rotation Crankshaft has value just like it sits. A 351W standard rotation crank core should be available at any crank grinder for not much money. A lot of those engines are not being built anymore.
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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I'm trying to convert the 78 engine to standard rotation and put it in the 91 sport nautique. I have the cam, lots of break in lube, all the premium gaskets, new exhaust man's, ect. The wick or helix lines are my only issue.
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Billy
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3738 |
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You can’t fix the Helix or wick lines in the block without removing the crankshaft from the block. Since it has to come out why not see if a standard rotation crank is available to bolt in. You would need to check your bearings for size. They are all stamped for size on the back of the bearing. Rods and Main bearings may be different sizes after a rebuild.
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Hellerides
Newbie Joined: June-01-2024 Location: Orlando Status: Offline Points: 20 |
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I understand I can't use the crankshaft from the 91 because it has a 1 piece rear main seal. I'm still going to try to pull the engine out of the 91 sport nautique today just in case it's an older motor. My mechanic is looking for a standard crankshaft in case I need it. Thanks so much for all your help. It's great that you all take the time to help us make a more informed decision. I'm retired so I'm able to focus all my efforts on this project. I would also like to wakeboard at least on more time b4 it's too late. I have 6 grandkids that love to wakeboard too!
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Billy
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