Recomended oil viscosity for crusader 270 350CI

Can anyone tell me the factor

Can anyone tell me the factory recomendation for the late 80's GM base 350 Crusader 270hp v8 engine?
Anyone have experience with using Mobil 1 in this type of engine? What would the recomended change interval be?

"Crusader's current online

"Crusader's current online maintenance manual recommends 15W-40 service SJ oil for air temps over 50F, 5W-30 service SJ for under 50F. They also specifically recommend not using synthetic oils and not extending the normal oil change interval (every 50 hours or 120 days.)

Even though your engine is an earlier vintage, this is a good guideline. I'd also take operating temp into account. If your engine runs below 160F, 5W-30 should do. Hotter, go with the higher numbers.

I've had success running carbureted 350 GM's using Valvoline DuraBlend (synthetic blend) 5W-30 in the cool months, changing to 10W-40 in the summer and following the 50 hour rule. Try to stay with the lighter oils unless your engine runs hot and hard. Most long term wear comes from cold starts after sitting for days or weeks at a time, not from cruising unless you run wide open.

"

" I'd like to hear a good

" I'd like to hear a good explanation why these engine manufacturers are so down on synthetic oils, Mercruiser has also come out against using synthetics in marine engines. Synthetic oils are vastly superior to petrolium based oils. They essentially don't breakdown with heat and usage which one of the principal reasons you change your oil. The other of course is due to impurity buildup which can be reasonably managed by replacing the oil filter. Mercruiser would like you to use their oil as they get a hefty markup on it. Aside from that the only reason I can think of is that they are worried that something in the synthetic oil might attack the seals in the engine. This I highly doubt since the synthetic manufactures would have addressed this problem over the 15 years that Mobil 1 and others has been on the market.

I had an acquantence several years back who worked for the testing department of STP. They evaluated all sorts of oils from various manufactures. He stated that the lubrication properties and the durability of Mobil 1 were unbelievable. That you could run a synthetic oil for 50,000 miles if not for the problem of it getting dirty.

The impurity problem is also being addressed. Some truck and tractor manufacturers are recommending 1000 hour oil change intervals with synthetics and regular filter replacement. Amsoil makes a special 1/10 micron bypass filter add-on to go with their synthetic which helps extend the change interval by keeping the oil cleaner. By the way Amsoil already states that gasoline marine engines can extend the change interval by up to three times or 12 months when using their special marine synthetic.

So the question remains, "Why don't Crusader and Mercruiser like synthetic oils?" My guess is that saying 'don't use it' is the simple and easy way out. They already know petroleum oils and what they do. So they don't have do any additional testing or go out on a limb if they just say 'stick with petroleum oils and follow the change interval found in the owners manual.' "

"With you all the way on this

"With you all the way on this topic, Bilgeguy. My theory is that mineral oils are a known quantity, predictable and time-proven despite the length of time that synthetics have been on the market. But it goes beyond that.......

Manufacturers look at motor oils with their warranty claim goggles on, opting for whatever will get an engine through its warranty period without problems. Synthetics, despite all their superior qualities introduce a risk factor, especially when extended oil change periods are involved.

That's not to say they're not interested in making their engines more durable, but that pales in comparison to not shelling out for warranty claims. Amsoil's statement sounds very reasonable, but I'll bet they're not willing to contract for reimbursement to Crusader or Mercruiser for oil related warranty claims.

I'll bet the refiner who makes Mercury's branded oil is under contract to pay all or a good part of any oil-related claims, or some similar liability/reimbursement situation. My thinking is that if synthetic oil producers would be willing to do that, you would see an immediate reversal of position by the marine engine manufacturers.

But hey, it's just my guess! ;^)

"

" Hey Coozertoo. I see no rea

" Hey Coozertoo. I see no reason why Crusader would escue synthetics if the change interval isn't extended. But you are probably right. They have contracts with all their suppliers, bearing and seal suppliers in particular, that transfer liability if there is a cronic problem and they probably haven't gotten these agreements extended to cover synthetic oils. But, this is mostly an administrative issue and we the user public should insist that they complete it.

Is there some forum where we can voice our opinion? If the user community can get the word out that capatibility with synthetic oils and extended change intervals are important to us, then this will become an opportunity for an engine manufacturer to distinguish himself against the competition. And this will get the ball rolling. "

" I think you are both right o

" I think you are both right on the mark. Years ago Porsche recommended against Mobil 1 claiming that it would rot the seals in their engines. At some point in the recent past they did a total about-face and began using Mobil 1 as the factory fill and recomended oil for all their engines. I used Mobil 1 in some of these older engines with no trouble and have had great service life out of them, even though some were producing 2hp/CI. I also agree that good filtration is key and can recommend the Mecca filters made by Canton racing products in Branford, CT. These are non-bypass type filters so that at startup or under high oil pressure situations there is no bypass to open and let unfiltered oil thru just when your engine needs clean oil the most. "

"As the saying goes, follow th

"As the saying goes, follow the money. I wish there were a forum that could get the ear of an engine manufacturer, but again, it's $$$$ that gets their attention.

A little story to illustrate how stubborn these guys can be when it comes to the bottom line. My dad was in the automotive parts manufacturing business for over 30 years, starting in the late 1940's. Around the mid-50's (I think!), Michelin took out a patent on radial tires. As we all know by now, they outperformed bias ply tires by a Texas mile and soon most of Europe was riding on radials.

But not in the good ol' USA, where neither tire makers nor car manufacturers were willing to pay what was then a relatively minor royalty to Michelin in order to make their own radials. My dad was in marketing and saw a tremendous potential demand for radials in this country. He convinced the prez of his company to go to Akron and try to get just one tire maker to pay Michelin and make radials. In turn, my dad's company offered distribution through Sears, Montgomery Ward, Western Auto and other jobbers. They also offered compensation to the tire maker if the venture failed. In return, they would get a percentage of sales.

Everywhere they went they were flatly refused. The explanation went something like, "Americans are happy with bias tires. They don't know about radials and sales numbers are great. Why should we sink capital into a new product - especially one that lasts longer! - when we're selling all we have now? Oh, and by way, we're sure as hell not going to pay a royalty to a foreign company for the privilege!"

It's not exactly like our synthetic oil discussion, but it's darn close. We all know how the story ends. It took an invasion of foreign cars with their Michelin tires to turn the tide. Given that manufacturers like Merc and Crusader will probably sell just as many engines with or without synthetic oil, it's hard to say what would convince them. If one mfgr were to get on board, most others would follow within months, so a competitive advantage would soon disappear.

Frustrating, no?

"

" You certainly have a sad sto

" You certainly have a sad story.

However I don't think that the situation is very similar.
1. Noone is being asked to change their product, only their attitude toward how the customer uses the product.
2. There is little or no retooling cost and it's associated capital investment.
3. They have no vested interest in how often we have to change oil (Mercruiser might have a slight interest due to their lubrication products business).
In short this is a no risk situation and most of the diesel engine manufacturers are already there with their trucking and industrial engines.

But the big diesel guys aren't the issue here. The boat with a couple of 1100 HP MAN's has an oil changing system and a crew or a yard to do it. It's us guys with one or two gas engines who chose that way to keep the boat cost down and who hate loose a Saturday in the middle of the season sucking the oil of the engine(s) and trying not to get any on the salon carpet while we're doing it.

I would think that any boat dealer would love to be able to tell their customers "You can run this little baby all summer long and not worry about the oil until you lay it up for the winter." Maybe we don't have the clout ($$$$) but if runabout manufacturer got together with with an (maybe unknown) engine manufacturer and built a boat which had significantly lower maintenance requirements they could make a big enough splash that even Brunswick would have to take notice.

Any ideas? "

" You guys seem well up on oil

" You guys seem well up on oils, I have a mercruiser 7.4 340hp and I know the recomended oil should be SAE 30 or secondly a multigrade 20W30 but I live on an Island off the beaten track. I can get my hands on shell helix 15W40 or castrol tection 15W40, these are API SJ rated not SE or SF. The only straight 30 that is around is shell gardinia with an API CD rating. Can you help? "

" My 1982 Crusader marine 270/

" My 1982 Crusader marine 270/350's spec 30W oil.

sence I will never use the boat in 20 degree weather I realy do not need a multi vis oil.

HOWEVER I now use AMSOIL 30w synthetic symply because it is better, and to get better fuel economy. My 2 cents.
Original 1982 270 Crusaders never had a valve cover off w/ 1000 hrs. They run @ factory spec RPM's on a 34' Silverton @ original top speed (+ 2 MPH) when launched with a clean bottom. "

" on this same subject, does a

" on this same subject, does anyone know if additives can be used on these engines and if so which ones. My engines are running a little warm 180F and I would like to increase fuel efficiency if that is possible. I was told to use SAE 30 in my 350's. Any comments? "

"Here's my 2 cents on synt

"Here's my 2 cents on synthetics and why engine mfgs may be hesitant to embrace them. They make your engine last longer! Much longer. As stated, they just want to make sure that their engines outlive their warranties. Any longer lives than that and they're losing money on replacement engines and rebuild kits. Planned Obsolescence is the mantra of the automotive industry as well as all major appliances and electronics now. Has anyone bought a new car lately? Have you read the manual or asked the dealer how often oil should be changed? Those nuts say things like every 25K, 50K, I've even heard 100K. We already know the filter can't take that, so what could they possibly have to gain from such ludicrous, unsound advice? New sales baby! If I ever get my Crusader 270s running I plan on stepping up to a better oil. Additives are cool and many do nice things, but my friend the race car engine builder swears by only one of them, Lucas. It is all the rage in all the autoparts stores in my area, and he's not from my area. It sticks to internal engine parts like thick mucous so there is no more startup wear. Some stores have the demo so that you can actually see how thick and viscous it is. They have additives for all systems: fuel, trans, engine, maybe even coolant. I'm just forwarding a recommendation from a very knowledgeable friend. I think they offer a guarantee too."

"Sorry bigdaddy. You ain't

"Sorry bigdaddy. You ain't gunna get significant, if any, improved performance from synthetics in a reciprocating engine. Keeping your oil clean is a tried and true method for longevity. With modern additive packages, conventional oils deliver 30+ years of service when kept changed regularly. I recommend avoiding gimmick oil additives. They can actually hinder the ability of the additive package that is in the oil already. One rare exception is to use a viscosity enhancer ( STP ) in an engine that is severly worn out and on it's last leg to milk a little more life out of it."

Hi all this is a little of the

Hi all this is a little of the oil topic that has come up but i was wondering if anyone new the performance numbers for a 1986 crusader 270. I recently purchased a boat in miami and am getting ready to bring it down to st. croix and am trying to find the fuel burn on the engines to help with trip planning. Any help would be greatly appriciated on the engines or trip planning!