Suggestions for Chrysler V8 - M360

[Bjorn]

I would very much apreciate input/suggestions as to which oil to use in my Coronet Playmate 21 DC - the engine is a Chrysler V8
Model M 360 5,9 liter - It is an engine from 1989 - so it is well used. Fresh water cooled -
What do u guys suggest : Synthetic - semi-synthetic ? Viscosity ?
I am also curious if anyone knows more abt. this particular engine ?
It is a rare engine in Europe....
Kind regards and thanks for your input in advance...

Bjorn / Sweden

 

[Crashbox]

The 360 will probably be happy on any 10W-30 synthetic, semi-synthetic or dino oil- your choice.

This particular engine is a descendant of the 273 engine from 1964 and is a good low-to-midrange RPM performer. Keep an eye on the timing chain, they tend to get real sloppy after about 120,000 miles (I don't know the equivalent number of hours). Also the cranks are cast instead of forgings so not good to wind it up to 20,000 RPM

In sum, a good, reliable "daily driver" engine.

 

[Bjorn]

Thanks very much Crashbox for yr reply.
Just bought this boat and have only used it a couple of times last autumn som my experience is very limited. No high rpms at all, say approx. 3.200 at 35-38 knots.

 

[Crashbox]

You're welcome, Bjorn.

The 360 should be very comfortable running at 3200 RPM, no doubt. I'm not sure of the redline on the marine engines but I do know the 360 was never intended to be a high-RPM engine like, say, a 327 Chevrolet.

One other thing about the 360 crankshaft: the main bearing journals are larger than the ones used in the 273/318/340 engines and so are not interchangeable should you decide to swap it out for whatever reason.

Also, you may want to consider doing an Auto-Rx treatment or two of them if it has a lot of hours.

Have lots of fun with your boat!!!

 

[lars11]

Hi. RPM are not extremely high on boats but they are constantly under very high load compared to an automobile. It's like constantly running uphill, close to full throttle with a car. In a car you would experience heat problems in that situation, in a boat the heat problems are covered by the water to water cooling.
But, locally in the engine there are high temps. Thats why other engine manuals recommend 20w50 dino or stratight 30 synthetic.
If you have a separate oil cooler you may step down in viscosity a bit.

 

[hemitom]

I have used quicksilver 25W40 in my inboard its a excellent oil for your application. This oil is blended with no V.I improvers so it will not shear as quick. It may not be available to you though. I think its made by shell for mercury marine. In my boat it performed better than a straight 30 and the 15w40 semi syn i had used before. Hope this helps you.

 

[Volvohead]

An '89 . . . it's probably carbureted. If so, fuel dilution is a much greater concern, even with FWC.

I would stick with a straight weight 30 or 40, or an HDEO 15w-40 conventional. If you want to feel better and poorer running a synthetic, do so. But I don't think your engine in that craft will generate loads that demand a full syn.

 

[Bjorn]

To Volvohead - Thanks for your input.
Yes the engine has a carburettor ( no injection)
I agree fuel dilution is a concern....

I would also like to thank Hemitom and Lars 11 for their input.

 

[Bjorn]

Guys...what about an oil with an " extra Zinc package " - since this is a flat tappet engine ?

 

[Volvohead]

If you can find ZDDP, use it.

Flat tappets are just one more reason to steer clear of lighter vis PCMOs in this particular application.

 

[Brett Miller]

Any HD 15W-40 would be my choice.

 

[alreadygone]

Is 3,500 actual max, or just where you prefer to run? If it won't turn any higher (say 4,200 or so) it's probably over proped and may experience burnt valves, holes in pistons, etc. While running continous WOT isn't a good idea, if engine won't turn up to factory recomendations isn't either.

Straight 30 or 40 wt would be my choice, as inboards will never be exposed to below freezing temps (more than once).

Bob

 

[Bjorn]

Yes approx 3.500 rpms is max.
What about oil pressure when starting up the engine with a single grade? Cool engine and oil...?

 

[lars11]

Hmm, I know the volvo 12w50 recommendation but now theres a huge sale on Valvoline Allfleet Extra 15w40 and Mobil Delvac MX 15w40. Would that do for shorter OCI of like 35 hrs in my 5.0Gi?

 

[oilboy123]

Originally Posted By: alreadygone
Is 3,500 actual max, or just where you prefer to run? If it won't turn any higher (say 4,200 or so) it's probably over proped and may experience burnt valves, holes in pistons, etc. While running continous WOT isn't a good idea, if engine won't turn up to factory recomendations isn't either.

Straight 30 or 40 wt would be my choice, as inboards will never be exposed to below freezing temps (more than once).

Bob



I have to agree with the over propped. RPM is too low for the speed. Is this a 18 ft range boat? I would think the max RPM would be in the 3800-4500 rpm range. If you can't get the engine to go higher rpm I would say over propped.

 

[james1]

I have a '73 Chrysler 340 marine engine. Max recommended RPM per the engine specs is 4000.

 

[Bjorn]

Even if this is an old thread- I would like to come back with some feed-back...
After digging into this I have realized that it is " over propped" and therefore decided to change - it now runs at 3.800-4.000 rpms and the result is much better....the boat is 21 ft. So many thanks " alreadygone" and " oilboy 123 "...!

 

[oilboy123]

Glad you got it set up correct for your app. You are fortunate to have a boat. I need to get one myself. Happy boating

 

[meep]

I've known a couple of chysler 318s in a 32' marinette. They readlined somewhere in the 3k range...3400-3500?

They were stroked compared to the automotive application and had a butt-ton of torque. Required high-torque starters... auto starters would fail within a year.

_They_Sounded_Amazing_ and were a pleasure to run.

Mike

 

[Pequod]

I have a 1999 Mercruiser Horizon 5.7l FWC and broke the engine on mercruiser 25w-40 oil for the first 50 hours and have been running Mobil 1 15w-50 synthetic for the past 10 seasons with great results...........No problems.