two engines or one

[Hammond Eve]

Gulfstar 36, 2 perkins engines, going from New Orleans to Brunswick, 1200 mi, 19 days, 1973 boat, engines burning, each 1.5 qts of 10 w oil per hour, at onset, threatened to scuttle the trip, not enough oil avail for this. started running only one engine and swithing every few hours. running both engines at 3400 rpm got 8.3 mph. running one engine at 3400 rpm got 7mph or a bit better occasionally. steering generally OK but somewhat cockeyed. used both eng only for exquisite maneuvering. first marina i came to bought 2 cases 40 wt oil and between that and single engine motoring saved the trip. by the time i got to GA the engines had reduced oil consumption to about a quart every 4 hours.

 

[rslifkin]

It sounds like those engines either have something seriously wrong, or they're just worn out. A quart in 4 hours is a serious amount of oil consumption.

 

[Hammond Eve]

they are worn out, long abused by previous owners. i am 81 and worn out sort of too, so we will just keep on keeping on.

 

[Gdavid]

What engines?, I ask because for that vintage of boat and engine, I would expect it to have a max engine speed of 2300 or 2600.

 

[Irish Rover]

On my 34' power catamaran I only use one engine apart from manoeuvring. I get 7mph @2,200 rpm on one engine and 8mph on 2 engines at the same revs. No issue steering and auto pilot works just fine on one engine.

 

[Hammond Eve]

perkins about 90 hp. could be the tac is off. most instruments on this boat are off or out. i put some massey ferguson stuff in it trying get some useful info.

 

[2savage]

10W oil doesn't sound right. WAY too thin. IMO you are losing oil from the sump past the control rings of each piston into the combustion chamber. I heavier grade of oil would reduce this. Check the engine specs again.

I have a Detroit Diesel 671 that uses 40W, which is the recommended grade. Even a multigrade 15W40 is considered a bad move. I don't have any consumption stats because I haven't owned the boat very long but looking at the two engines together leads me to believe your grade is wrong.

3400 rpm? Should be half of that.

 

[SteveK]

10W oil doesn't sound right. WAY too thin. IMO you are losing oil from the sump past the control rings of each piston into the combustion chamber. I heavier grade of oil would reduce this. Check the engine specs again.

I have a Detroit Diesel 671 that uses 40W, which is the recommended grade. Even a multigrade 15W40 is considered a bad move. I don't have any consumption stats because I haven't owned the boat very long but looking at the two engines together leads me to believe your grade is wrong.

3400 rpm? Should be half of that.

+2
15-40 keeps popping up in general search. If it burns rings or valve stem wear. Look for high millage oil or an additive . Especially for long hour runs where it will thin out as it gets hot.

 

[Lepke]

10w is the equivalent of hydraulic oil. Way to light for an engine. Older, worn engines do better on heavy weight oil, 40w or 50w. In really cold weather a multi grade. Probably not needed in Georgia.

 

[Hammond Eve]

Previous owners used 10w 30. Your response is quite helpful. I am going to switch to 50w.

 

[rslifkin]

10W-30 is definitely a bit thin for most diesels. I'd go up to a 15W-40 and see what that gets you, as it's a commonly available diesel oil. 20W-50 diesel oil is not common, so I'd only go there if it proves necessary.

 

[Bugaboo]

Gulfstar 36, 2 perkins engines, going from New Orleans to Brunswick, 1200 mi, 19 days, 1973 boat, engines burning, each 1.5 qts of 10 w oil per hour, at onset, threatened to scuttle the trip, not enough oil avail for this. started running only one engine and swithing every few hours. running both engines at 3400 rpm got 8.3 mph. running one engine at 3400 rpm got 7mph or a bit better occasionally. steering generally OK but somewhat cockeyed. used both eng only for exquisite maneuvering. first marina i came to bought 2 cases 40 wt oil and between that and single engine motoring saved the trip. by the time i got to GA the engines had reduced oil consumption to about a quart every 4 hours.

Where is the oil going do you have smoke how does the engine start when cold.If it starts well when cold your rings are probably good.If you have a Lotta smoke then you’re burning it , oil in the water I would look for another cause I’m assuming you’re oil not in your bilge . 3400 RPMs is way way too fast . it’s not a crime to know Nothing about engines you need to get somebody that does soon

 

[Hammond Eve]

engines start after about 3 revolutions, when cold. mild white smoke exhaust for several minutes when started cold, clearing up after 5 min. After 1200 miles,mild thin blackening on transom. oil not in bilge. I am stuck with this situation, I and boat too old to mess with rebuilding engines. So, whats wrong with running it at 3400 rpm, assuming that is accurate, which is questionable considering that one tac does not work at all. About the oil, thicker proves to be better with regard to oil consumption, so would that not rule out getting a multiviscosity oil, where viscosity seems to be reflected in the lower number?

 

[rslifkin]

For multiviscosity, a 15W-40 is a 40 weight when warm, but it doesn't thicken as much as a straight 40 when cold, so at low temperatures it's similar in thickness to a cold 15 weight.

 

[Hammond Eve]

very helpful, thank you. the 15w turns into a 40 when it warms, which is when the engine gets warmed up. i not think most people on earth know this.

 

[RT Firefly]

Greetings,
Warning: Slight thread drift...Re: Post #7. Mr. 2s. "I have a Detroit Diesel 671..." Gonna be tough to figure actual oil consumption on a "Screamin' Jimmy". They're notorious leakers. It's said if you have a picture of a Jimmy on the wall, you have to put an oil diaper underneath it...


GREAT engines in spite of that.


Back to our regular programming.


Mr. HE. Agree with other members. Simply go with a higher viscosity single grade oil and I also agree with your philosophy-if it ain't broke, don't fiddle with it.

 

[jgwinks]

The ten weight probably did a good job of flushing the gunk out of the engines, my dad did that with his delivery trucks back in the '60's. Filled with 10 wgt, ran for 20 minutes then changed again with 30. That's about all it's good for. Downside is sometimes the gunk is all that keeps the oil from leaking out. Try 40 or 50 wgt, should do much better. Do they make "high milage" oil for diesels? I've never seen it, but I use high milage gas engine oil in my older cars.

 

[Hammond Eve]

this has all been most helpful. thanks to every one of you.

 

[backinblue]

very helpful, thank you. the 15w turns into a 40 when it warms, which is when the engine gets warmed up. i not think most people on earth know this.

Hmmm, I thought most everyone knows this. No disrespect, but it's one of the most basic properties of oil.

 

[SteveK]

engines start after about 3 revolutions, when cold. mild white smoke exhaust for several minutes when started cold, clearing up after 5 min. After 1200 miles,mild thin blackening on transom. oil not in bilge. I am stuck with this situation, I and boat too old to mess with rebuilding engines. So, whats wrong with running it at 3400 rpm, assuming that is accurate, which is questionable considering that one tac does not work at all. About the oil, thicker proves to be better with regard to oil consumption, so would that not rule out getting a multiviscosity oil, where viscosity seems to be reflected in the lower number?

So are you pulling our legs with 3400 rpm?
Is this your engine rated to run at up to 2400, may not burn as much running at 2000
View attachment C10550628.pdf

 

[Hammond Eve]

that graphic is most informative. thank you for attending to this so well. I would not presume to be so offensive as to waste anyone's time and good will on this. One tac is defunct, the other says I have been running at 3400 rpm. Is it correct to infer from that graph that the engine will not turn much over 2400 rpm regardless? If so, tac is inaccurate. That being the case, what to do about it. I got to that point by looking for a sweet spot, how does it sound, smooth? overloaded? comfortable?, and 3400 is the max it seemed to be purring along with. So in actuality it was probable something below 2400.

 

[rslifkin]

Easiest way to sort out the tach situation is to buy an inexpensive optical tach. You then put a white mark on the crank pulley and use the optical tach to take an RPM reading. Most dash tachs have a calibration adjustment, so assuming the dash tach isn't broken, you can calibrate it and make it accurate.

 

[Bugaboo]

How much throttle do you have left do you have the throttles pegged or about halfway if you are running at 34 3600 RPM the only reason that engine hasn’t blown up is because it’s a Perkins if it is a 4–236 one of the best engines ever made if it was a Ford You would’ve blown it up guaranteed Need to know what engine you have and if turbo charged if it is I need to know that

 

[SteveK]

I suggest see what WOT rpm is and then pull back about 5-600 for cruise. That is a start.
Get tach's fixed is the end solution and maybe will also reduce oil loss.

 

[Nomad Willy]

What engines?, I ask because for that vintage of boat and engine, I would expect it to have a max engine speed of 2300 or 2600.

The Perkins 4-107 or 4-108 usta be a London taxi cab engine and they ran up to 4000rpm. 3400 shouldn’t be a broblem in itself so there must be some problem. Like no dip stick … ??

 

[SteveK]

................Like no dip stick … ??

I spent an hour looking for one on the wife BMW, there is none!

 

[Nomad Willy]

I spent an hour looking for one on the wife BMW, there is none!

Yup w a 2013 or 2014 Jetta I couldn’t find the oil filter .. assuming it was a “spin-on”. The dealer had to point it out.

 

[backinblue]

Correct, BMWs have no dipstick, just electronic sensors. Also many cars have gone back to canister oil filters, BMW and VW being 2 that I know of. Not sure why, maybe to make it more difficult for DIY maintenance. My BMW engine lends very little for the owner to see under the hood. I had to watch a youtbe video to find the brake fluid resevoir. Maybe it's just German engineering but certanly not maintenance friendly. You'd think a cabin air filter should be 2 minutes, it's a big job on my car. Seems unnecessarily so, but German's have their reasons for everything!

 

[rslifkin]

Correct, BMWs have no dipstick, just electronic sensors. Also many cars have gone back to canister oil filters, BMW and VW being 2 that I know of. Not sure why, maybe to make it more difficult for DIY maintenance. My BMW engine lends very little for the owner to see under the hood. I had to watch a youtbe video to find the brake fluid resevoir. Maybe it's just German engineering but certanly not maintenance friendly. You'd think a cabin air filter should be 2 minutes, it's a big job on my car. Seems unnecessarily so, but German's have their reasons for everything!

Seems like a great contrast from my 20 year old BMW. Easiest car I've ever done an oil change on (cartridge filter is front and center, takes seconds to change and not messy). And the cabin air filters take 2 minutes to change (although the recirculation filters are a pain).

 

[SteveK]

Yup w a 2013 or 2014 Jetta I couldn’t find the oil filter .. assuming it was a “spin-on”. The dealer had to point it out.

Let me guess, a drop into canister up top like my camaro