Oil Leak Dart M big blocks
 

Hi guys,

I have two new Dart block engines.

They are running with very high oil pressure ie 100psi.

I am finding oil is coming out of where the oil breathers clip in to the rocker covers. Also, Oil is coming out where the caps go on the rocker covers.

When I first took it out I found the dipsticks had actually blown forward out of the cases.

I emailed the guy I bought it from and he said the oil pressure on Darts is normal that they do run very high, and that I should be getting some better fitting rocker covers with breathers.

Any opinions on this would be very helpful.

Shouldn't be that high. It is not the block. This guy says it is normal because he most likely builds the same way every time. THere will be some good help on this forum. He could be using high pressure pumps, in stead of high volume. He also could have a pug in the wrong spot in the block. I am not sure where though.

Hopefully someone else on the forum can give some better help.

thanks Jeff.

I will see if I can look up in the receipts what was used.

Too much oil pressure, dont know why you would need 100 lbs. holy cow. Probably oil pump. someone else here should be able to help.:violent-smiley-045:

If I use the boat with this pressure am I likely to blow the motors at full speed?

(i'm not that mechanical).

First of all, if you're blowing the dip sticks out of their tubes, that's telling me that you not only might have way too much oil pressure, but you surely have way, way too much blow by in the crankcase. The excessive oil pressure will not blow the dip sticks out of their tubes. You will usually end up washing out the bearings.

The last time I seen a pair of engines blow the dip sticks out of their holders, we did a leakdown test on the engines, and they had over 35-50% leakage in all the cylinders.
Sounds to me that the high oil pressure is the least of your worries. I'd be looking at what's going on in your crankcase, ie/ piston to wall clearance, ring end gap, if you even have any rings at all on the pistons !! Not trying to be a smart azz, but you really need someone that's very knowledgable in doing leakdowns, and have them give those engines a total once over before you seriously hurt them.

Frank

The engine is running 100psi on the port and 95psi on the starboard when warmed up and oil is pouring out of the breather/cap.

I was going to sikaflex the breather down and i've got some new caps to go on the rocker covers to see if that helps.

The dip sticks blew out the first time I took it out (but it hadn't been used for three months or so...not sure if that makes a difference).

Is it a big job to fix these problems?

YES!!!!!!

Like was said, the Dart block won't cause high oil pressures. The wrong springs in the oil pump will. It should have a high volume pump with a low pressure spring.

It can't be fixed without pulling the engines and pulling the oil pans.

If its blowing out the dipstick, it could be "blow by"
Blow by happens when the pistons rings are too loose and air gets past them during combustion and goes into the crank case.
It get fixed by pulling the engines and doing rebuilds.

It could also be related to high oil pressure. If the breathers on the valve covers are so oil saturated that air can't escape.

Man, that is not good news.

Its summer here and i've got a hot date on Saturday and told her i'd take her out in my cigarette!

My mate who was a manager at mercury said "I was once told that for every foot long your cigarette is, is how many chicks you will shag in that boat"...love the theory...and first date on it is this saturday!!!!!
Damn.

I had the breather sturation problem once.

Take your breathers out and see if you are stil blowing the dipsticks out. If not. Change your breathers. You could be presurising the crankcase from bad valve seals. Also some builders use the little O- Ring style seals that really high performance dragsters etc use. THese things move up and down with the valve and allow tremendous blow by.


You are still going to have to pul the engine to get the oil pressure down. The guy may not have enough clearane on the crank and that could be causing high oil pressure.

Are these custom engines that you spent a bunch of money on? I hope not, because you really need to have them torn down and the details checked by a really experienced engine builder.

Don't know what you guys have to work with over there.

Maybe you will get lucky and it will rain saturday and you can just hang out in the marina, rev the motor and shag anyway.

My buddy used to just idle up the the bar on his one good engine early in the day, chicks would see our boat and want to go sit on it, he would then proceed to get really wasted and promis them a ride the next day if he would give them a ride home in there car. Worked every time.

Your oil pressure is WAY too high. The old school rule of thumb on a wet sump chevrolet engine was 7 to 10 psi per thousand RPM. Running the pressure that high is going to cause you additional problems over time.

Way too much oil pressure.

What are some of the specs on your motors? Are they blower motors or N/A. The more info the easier it may be to help you.

Im sure you've looked at the obvious but how much oil is in the motor?

The engine doesn't have blowers on it.

Oil Levels are ok.

I think they are 509ci? about 650hp each. They were custom built motors from a company in Jacksonville.

HEY your Mate was absolutely right for every foot = shaggin a hot chick except you misunderstood him,He said SKATER not cig and with a SKATER its every weekend
Rock on its a SKATER NATION :cool-smiley-027::cool-smiley-027:

Maybe she'll be multi talented, a good shag and just maybe she can fix my boat too!. I'll be married by sunday.

Brent,
Doesn't sound good mate!, if your looking for engine builders to call try Brian at Liberty Speed in Tamworth or Sam and Issy at COME Racing in Melbourne, all stand up guys with a wealth of knowledge around marine engines.
NL

Thanks NL.

Come racing. I've heard of them. YOu say they've had a lot to do with marine engines?

Regards,

Brent

Liberty more so than COME

What the hell are you doing wating good DART Blocks on 509"s for?

For crying out loud?:hitfan:

Jeff, I didn't build them up!. I bought the boat with them. They are brand new. I'll post some pics.

engine pics
 

These are the two engines
nope, cant upload them :(.