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gerritm
06-22-2009, 09:16 AM
I need some help from the experts. Maybe someone has had the same problem or can give me an idea what to look for.

I have staggered 525's in my '05 -- 42 Fountain Ex. When we bought the boat both engines had bad #8 cylinders from detonation and the tops of the pistons were cooked. We had both engines rebuilt. After a short period of time we noticed a fine mist of oil on the starboard saddle tank and some oil floating on the water in the bilge. It seems to come and go and is worst when we run the boat hard at full rpms. If we run easy it doesn't seem to show up. It is directly across from the forward port engine. The mist isfrom the bilge to the bottom of the hatch and all over the saddle tank. My mechanic has gone over every connection, oil plug, distributor seal etc trying to find the leak. It has to be dropping on the driveshaft and getting slung or misting out of something. There are no obvious leaks. Any ideas what it could be?.

Ted
06-22-2009, 09:52 AM
Is it even with the front or the rear of the engine?

gerritm
06-22-2009, 02:20 PM
Is it even with the front or the rear of the engine?


It seems more towards the rear. The mist is concentrated at the back of the saddle tank. We have pulled off all the rear covers and even put dye in the oil but it is so dispersed the black light picks it up all over.

Ted
06-22-2009, 02:44 PM
There are known issues with the rear main seal on 502 blocks misting oil under a load, I think some of it has to do with the loose clearances they run for better oiling and the crank deflecting slightly.

gerritm
06-22-2009, 04:13 PM
There are known issues with the rear main seal on 502 blocks misting oil under a load, I think some of it has to do with the loose clearances they run for better oiling and the crank deflecting slightly.

Kind of had a feeling that was what the problem is. We eliminated most everything else. Hoping it was a little simpler. Any issues with it blowing out the seal and losing all oil pressure? Do you think it is something I can live with until I can pull the motor in the future? It has been going on for about a year and does not seem to be getting much worse.

Chris
06-22-2009, 04:37 PM
The BBC design doesn't ventilate the crankcase very well. Bottom-end windage can cause excessive lower crankcase pressures that don't help these problems. I can't remember who makes it, but I've seen vent plates that bolt to the block in place of the fuel pump- they have an AN fitting in them that you can plumb to a tank.

Ted
06-22-2009, 04:51 PM
I know several people that have run better than 100 hours like that, it doesn't seem to get worse and does not effect the seal as far as anyione can tell.

Offshoredrillin
06-22-2009, 08:05 PM
when the motors were rebuilt, some time the seal will wear a small groove in the crank, there are 2 different seals if I remember correctly as well, you may have one that is a c.h. too big. if the crank was scored from running lean and heat you may find the problem there.

gerritm
06-23-2009, 08:31 AM
The BBC design doesn't ventilate the crankcase very well. Bottom-end windage can cause excessive lower crankcase pressures that don't help these problems. I can't remember who makes it, but I've seen vent plates that bolt to the block in place of the fuel pump- they have an AN fitting in them that you can plumb to a tank.

Chris, I am not sure what you mean. Are these vents plates run to the cooling system or water intake? Do you think it is excessive crankcase pressure due to heat? It does semm to be worse now that the temp is up in the 90's.

Tony
06-23-2009, 08:53 AM
Degrease and scrub the motor and bilge. Go to napa and buy a small bottle of engine oil dye and dump in, run the boat then check the bilge with a UV light in a dark room.

Ive used this method more than once to locate the source of leaks.

Chris
06-23-2009, 09:20 AM
Chris, I am not sure what you mean. Are these vents plates run to the cooling system or water intake? Do you think it is excessive crankcase pressure due to heat? It does semm to be worse now that the temp is up in the 90's.

You get crankcase pressure due to windage and blowby. The vents allow this to vent out to the atmosphere. You can run them to a catch tank. Outside temp shopuldn't have anything to do with it. Typically not a problem until you get into big inches, blowers and high RPM. You may want to look at your existing ventilation to see if there are any issues or obstructions.

ROGUE
06-23-2009, 12:26 PM
Degrease and scrub the motor and bilge. Go to napa and buy a small bottle of engine oil dye and dump in, run the boat then check the bilge with a UV light in a dark room.

Ive used this method more than once to locate the source of leaks.

Or, if you are using a synthetic oil, Fantastic cleaner will turn a bright purple when it hits any synthetic oil I have seen. T

OldSchool
06-23-2009, 12:50 PM
I can run all day @ 4000 rpm's and the bilge will be spotless. A few good minutes above 5800 and it's a mess. Big cubic inch engines will spray a little oil out of the rear main seal when they get the snot run out of 'em.. at least mine do! They're coming up on 100 hours and they've both done it from the get go. I change the oil every 25 hours and I've never seen either engine be even 1/4 of a quart low.


It's amazing how much of a mess just a an ounce or two of oil can make!!!:puke::puke::banghead::cheers2:

gerritm
06-23-2009, 02:09 PM
Degrease and scrub the motor and bilge. Go to napa and buy a small bottle of engine oil dye and dump in, run the boat then check the bilge with a UV light in a dark room.

Ive used this method more than once to locate the source of leaks.

We have done this a couple of times. The leak is a mist and it goes everywhere. There is no way to pinpoint one spot or leak. It looks like a light show in the engine compartment with the black light.

gerritm
06-23-2009, 02:14 PM
I can run all day @ 4000 rpm's and the bilge will be spotless. A few good minutes above 5800 and it's a mess. Big cubic inch engines will spray a little oil out of the rear main seal when they get the snot run out of 'em.. at least mine do! They're coming up on 100 hours and they've both done it from the get go. I change the oil every 25 hours and I've never seen either engine be even 1/4 of a quart low.


It's amazing how much of a mess just a an ounce or two of oil can make!!!:puke::puke::banghead::cheers2:

This sounds just like my engine. Run it at 4K rpm and almost nothing. Run it hard like we did this weekend in our Topps poker run and the couple of ounces of oil make a big mess. I squirt down the bilge and engine compartment with Purple Power and spray it off to keep it clean. I feel better that only 1 engine does it. I put a quart in every couple of times out and change the oil every 25 hours or so.

Blue Thunder
06-28-2009, 07:08 PM
Plug up all the crankcase openings and figure out a way to put compressed air in the crankcase. 15psi is good. Then listen for the leak and/or use soapy water solution to spray the soapy water around the area and look for bubbles. I found a pesky leak just today after having the engine out twice looking for this leak and everything looked perfect. It turns out it was a valve cover gasket that visually I have no idea why it would no seal. This was an elevated rpm thing too.

BT

Geronimo36
06-28-2009, 08:27 PM
I can run all day @ 4000 rpm's and the bilge will be spotless. A few good minutes above 5800 and it's a mess. Big cubic inch engines will spray a little oil out of the rear main seal when they get the snot run out of 'em.. at least mine do! They're coming up on 100 hours and they've both done it from the get go. I change the oil every 25 hours and I've never seen either engine be even 1/4 of a quart low.


It's amazing how much of a mess just a an ounce or two of oil can make!!!:puke::puke::banghead::cheers2:

Mine do the same thing under boost.... My other buddie has the same issue.

Was thinking it was a JC thing but then realized you had yours re-done by MGD.

OldSchool
07-01-2009, 11:11 AM
Was thinking it was a JC thing but then realized you had yours re-done by MGD.

One redone..One complete new engine.

Ratickle
07-01-2009, 11:19 AM
Do you have a picture of your engines for the ventilation review? My 540's on the Scorpion are terrible at it, if I run with the breathers only, I have to wipe it up a lot.

gerritm
07-31-2009, 01:38 PM
Plug up all the crankcase openings and figure out a way to put compressed air in the crankcase. 15psi is good. Then listen for the leak and/or use soapy water solution to spray the soapy water around the area and look for bubbles. I found a pesky leak just today after having the engine out twice looking for this leak and everything looked perfect. It turns out it was a valve cover gasket that visually I have no idea why it would no seal. This was an elevated rpm thing too.

BT

The leak is getting worse. When you say plug up the crankcase openings and put compressed air in, other than making sure the oil fill caps are on tight, what else do you plug? I can make a fitting to screw on to the dipstick/oil drain hose connection to add air. Is this going to work?

gerritm
09-16-2009, 09:34 AM
I am beginning to think it may be an over pressure problem. We have found oil puddling on top of the fuel filter in the little recesses. It still is only happening at max rpm (5K plus). Can it be blowing out of the dipstick? What are the causes. I know there is a pcv valve somewhere down below the intake. Could that be plugged? I covered the dipstick and tied a rag around it to see if this is the source. Next good run may tell.

DAREDEVIL
09-16-2009, 09:38 AM
I am beginning to think it may be an over pressure problem. We have found oil puddling on top of the fuel filter in the little recesses. It still is only happening at max rpm (5K plus). Can it be blowing out of the dipstick? What are the causes. I know there is a pcv valve somewhere down below the intake. Could that be plugged? I covered the dipstick and tied a rag around it to see if this is the source. Next good run may tell.

Usually its the dipstick.

gerritm
09-17-2009, 05:07 PM
Usually its the dipstick.

What do you think would cause this?

PARADOX
09-19-2009, 05:51 PM
Gerr.

Not a motor head here, but try one more thing. It may be as simple as a leak at the fuel pump. (I had one on a nother boat. only at high RPMs.) The seal may leak a little and air flow from the motor housing vents and the front engine pooleys, serpentne belts, alternator etc will push the oil everywhere. Took me for ever to find it.
Don't recommend this, but I was in the bilge at FT while some one else was driving and I was looking for the leak. I did find it, $3 part and I was good.
Good luck.

MERPerformance
09-19-2009, 08:13 PM
I need some help from the experts. Maybe someone has had the same problem or can give me an idea what to look for.

I have staggered 525's in my '05 -- 42 Fountain Ex. When we bought the boat both engines had bad #8 cylinders from detonation and the tops of the pistons were cooked. We had both engines rebuilt. After a short period of time we noticed a fine mist of oil on the starboard saddle tank and some oil floating on the water in the bilge. It seems to come and go and is worst when we run the boat hard at full rpms. If we run easy it doesn't seem to show up. It is directly across from the forward port engine. The mist isfrom the bilge to the bottom of the hatch and all over the saddle tank. My mechanic has gone over every connection, oil plug, distributor seal etc trying to find the leak. It has to be dropping on the driveshaft and getting slung or misting out of something. There are no obvious leaks. Any ideas what it could be?.Check the harmonic balancer, groove from seal. You can get a sleeve for it. Or maybe the timing cover, it has a o-ring all around it.

gerritm
09-21-2009, 05:09 PM
Gerr.

Not a motor head here, but try one more thing. It may be as simple as a leak at the fuel pump. (I had one on a nother boat. only at high RPMs.) The seal may leak a little and air flow from the motor housing vents and the front engine pooleys, serpentne belts, alternator etc will push the oil everywhere. Took me for ever to find it.
Don't recommend this, but I was in the bilge at FT while some one else was driving and I was looking for the leak. I did find it, $3 part and I was good.
Good luck.


One of the 2 metal fuel lines going to the back of the fuel filter had oil dripping from it. It was the one closest to the block. Almost looked as if the line was leaking, but it was oil not fuel. The fuel pump is right below the filter housing.When you say the seal, are you talking about the seal that goes between the pump and the block. Is there oil at that point where the fuel pump seals against the block?

We were thinking of the riding in the bilge to check it out. If it wasn't at full throttle, I would be too nervous, but don't want to hurt anyone bouncing around or lose my engine hatches. My luck is they would blow off.

Ratickle
09-21-2009, 05:13 PM
Is there oil at that point where the fuel pump seals against the block?



Yes.

gerritm
09-23-2009, 08:53 AM
Yes.

Thanks, I will check it out.

DAREDEVIL
09-23-2009, 09:01 AM
What do you think would cause this?

Damn,,,they said it all. It could be all of the above.
+ if you have a edelbrok fuel pump ,,it has 2 little holes in the side on the housing,if the inner seal goes bad that is where the oil comes out.

That is what they are for . to see oil ,,so u know its bad. Not kidding either.
A friend of mine just had exactly that 2 days ago.

PARADOX
09-23-2009, 09:24 AM
One of the 2 metal fuel lines going to the back of the fuel filter had oil dripping from it. It was the one closest to the block. Almost looked as if the line was leaking, but it was oil not fuel. The fuel pump is right below the filter housing.When you say the seal, are you talking about the seal that goes between the pump and the block. Is there oil at that point where the fuel pump seals against the block?

We were thinking of the riding in the bilge to check it out. If it wasn't at full throttle, I would be too nervous, but don't want to hurt anyone bouncing around or lose my engine hatches. My luck is they would blow off.

I don't reccomend the bilge riding either. :leaving:

There is a gasket/seal at the fuel pump and block. Try to wrap paper towels around the area and tape it down so it won't blow around. Drive and see where you might get oil. YOu can try towels different areas on the engine. THis will stop from "spraying" and you can pin point the source better.

Geronimo36
09-23-2009, 11:08 AM
You may also want to check the RTV seal below your intake manifold at the front/back in the lifter valley area. They have a high tendancy to leak and the oil can usually make its way down the front/back of the block and even down the side of the block where the head/block meet. When it leaks out the back you can ususally see a little oil near the bell housing area and/or on the spark plug wires as they wrap underneath the engine.