7.4 bravo Oil line confusion

J

jere1972

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think I need some help I removed my engine to rebuild the transom, I figured since the engine was out I would strip it down clean and repaint, problem I may have is the engines oil lines to the filter relocation adapter, not certain I have them correct, off the engines GM factory filter location, there is a a short line that runs to the oil cooler then there is a line off the rear on a 90 i have the line that comes off the oil cooler going to the IN port on the filter adapter then the OUT goes to the rear 90 deg on the engine original filter location, anyone know if this is correct, I can't seem to find any info on this, also should the area under the valve covers be saturated with oil while the engine is running, I can see signs of oil when the oil fill plug is removed but not a lot, the oil pressure is @ 38-40
 
Don S

Don S

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Re: 7.4 bravo Oil line confusion

Which 7.4 do you have? Got an engine serial number handy?
 
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jere1972

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Re: 7.4 bravo Oil line confusion

no serial # I can't get to the ID plate to read it, the engine is in a 91 boat and is original, and reinstalled it is carburated, has the thunderbolt ignition if that helps any
 
A

Another retired guy

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Re: 7.4 bravo Oil line confusion

To answer your last question - yes, you should see oil under the covers. If you didn't, that would be the time to worry!
 
Don S

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Re: 7.4 bravo Oil line confusion

Nothing in the manual about it, but here is from a part lookup program, it might help sort them out.

Untitled3.jpg
 
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jere1972

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Re: 7.4 bravo Oil line confusion

I was not certain if there should be alot of oil slushing around under the covers, I know on overhead cam motors there is, not certain on these older engines, the oil was minimal, but there,
I am concered I do not have the engine oil lines IN/OUT correct, never paid attention to them when I took them off and all fittings are the same size unlike the power steering lines which were a no brainer
 
A

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Re: 7.4 bravo Oil line confusion

jere1972 said:
I was not certain if there should be alot of oil slushing around under the covers, I know on overhead cam motors there is, not certain on these older engines, the oil was minimal, but there,
Click to expand...

The rocker arms are up there and they need lubrication. There will be oil leakage all along the assembly. Not a lot, but there has to be some.
 
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TilliamWe

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Re: 7.4 bravo Oil line confusion

jere1972 said:
...also should the area under the valve covers be saturated with oil while the engine is running, I can see signs of oil when the oil fill plug is removed but not a lot...
Click to expand...

I wouldn't use the word "saturated", but there should be a little. But I have also adjusted valves with the the engine running, and it's not "spraying" all over the place, either. When you take the oil fill cap off a GM V6 car engine, oil doesn't come flying out, and you can't see pools of it in the top of the head.
 
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jere1972

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Re: 7.4 bravo Oil line confusion

thanks for the info guys, any further thought on the oil lines?
 
picklenjim

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Re: 7.4 bravo Oil line confusion

jere1972 said:
think I need some help I removed my engine to rebuild the transom, I figured since the engine was out I would strip it down clean and repaint, problem I may have is the engines oil lines to the filter relocation adapter, not certain I have them correct, off the engines GM factory filter location, there is a a short line that runs to the oil cooler then there is a line off the rear on a 90 i have the line that comes off the oil cooler going to the IN port on the filter adapter then the OUT goes to the rear 90 deg on the engine original filter location, anyone know if this is correct, I can't seem to find any info on this, also should the area under the valve covers be saturated with oil while the engine is running, I can see signs of oil when the oil fill plug is removed but not a lot, the oil pressure is @ 38-40
Click to expand...
Kind of hard to understand exactly about the adapter on the block. Is the short line going to the cooler coming out of the CENTER of the adapter on the block and is the 90* fitting more to the outter part of the adapter on the block. If so you have then wrong. Clean oil returning into the engine from the filter goes into the center. If necessary pull off the adapter and see which hole goes into the center where you would normally screw on a filter. What would be happening is you would be running the oil through the remote filter backwards. Here's a diagram that may help.
http://teaguecustommarine.com//media/drawings/oij_piping.pdf

Notice in the diagram how the oil flows out of the filter center where it screws on. It must do the same thing on the block adapter flowing in the center. Hope this makes sence to ya.
 
tpenfield

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Re: 7.4 bravo Oil line confusion

I have a bunch of pictures from my 1991 Mercruiser 7.4 rebuild that may show you the correct hose connections. I can post them when I get home tonight.

also, I have a video of what the engine looks like running with the valve covers off . . . Some oil squirting, but not exactly torrential.

i can post a link to that too, later this evening . . Or just search Formula242ss on youtube, and you should get to my videos.
 
tpenfield

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Re: 7.4 bravo Oil line confusion

Here are a few photos from my rebuild that may help figure out the oil lines . . .

100_0746.jpg


100_0737.jpg


100_0738.jpg


100_0732.jpg


Here is a video showing the valve covers off . . .


I hope this stuff helps
 
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jere1972

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Re: 7.4 bravo Oil line confusion

thanks the pics help, looks like in the pics the line running to the filter output port goes to the cooler, in that case mine is wrong
 
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jere1972

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Re: 7.4 bravo Oil line confusion

well after looking @ picklenjims diagram, which looks like the way I have mine, I'm back to be uncertain, I know that the hose from from the block adapter to the oil cooler is correct, that is the short line from the front adaptor port to the cooler, then from the cooler the line runs up to the in port on the filter relocation plate, then the out runs to the port on the block near the side rear,
 
picklenjim

picklenjim

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Re: 7.4 bravo Oil line confusion

OK here is how you can figure it out easy. We know the hoses are all correct at the bottom so if anything the 2 connecting to the remote filter base MAY or MAY NOT be correct. Disconnect the IN hose at the filter. Now disconnect the coil wire or unplug the distributor so the engine won't start. Hold the end of the hose in a cup and have someone crank the engine for a few seconds. If oil comes out of the hose then the hose connects to the IN so they are correct. If oil comes out of the filter mount base when cranking then the hoses are backwards at the filter base.
 
picklenjim

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Re: 7.4 bravo Oil line confusion

jere1972 said:
thanks the pics help, looks like in the pics the line running to the filter output port goes to the cooler, in that case mine is wrong
Click to expand...

I looked through some merc parts diagrams (couldn't find one exactly like yours) but they did show the flow going through the filter first and then the cooler. Therefore it may be correct that the filter out port goes to the cooler. It really doesn't matter if it goes through the filter or oil cooler first, it's just the diagram I posted showed the cooler first. It's a generic high performance set up diagram, sorry if I added to the confusion. Still I would check it like I explained in post #15. You know the bottom lines are correct, you just want to be sure your flowing through the filter the right direction.
 
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