Mountain vs. Mole Hill - Zinc Oils

TRBenj wrote: I believe the recent SBC's (Excalibur, and maybe the Apex and 5.0 HO base motor) are rollers. The 6.0 ZR6 is surely roller as well.

Does anyone know if my SBC Excalibur is a roller motor and what oil should be used or if the Zinc is required? The manual indicates SAE 15W-40 "SM".

quinner wrote: TRBenj wrote: I believe the recent SBC's (Excalibur, and maybe the Apex and 5.0 HO base motor) are rollers. The 6.0 ZR6 is surely roller as well. Does anyone know if my SBC Excalibur is a roller motor and what oil should be used or if the Zinc is required? The manual indicates SAE 15W-40 "SM".

The SBC went roller in '88 for GM cars, and '96 in GM trucks. Im assuming that has trickled down to the marine stuff by now- but it might not hurt to put a call into PCM.

If thats the case, then the extra zinc isnt required (but it wouldnt hurt either).

BuffaloBFN wrote: wish mine had been taken care of like that all its life! what marinization is the '95?

Buffalo, Malibu used Mercruiser marinization up to production year 1997. After 97 they switched to Indmar.

nuttyskier2002 wrote: BuffaloBFN wrote: wish mine had been taken care of like that all its life! what marinization is the '95? Buffalo, Malibu used Mercruiser marinization up to production year 1997. After 97 they switched to Indmar.

They certainly weren't using Mercruiser exclusively in 97. I've been in a 97 Response with the Monsoon.

I switched my boats to Valvoline Racing 20W50 as of late 2005. I did a lot of reading to make that decision.

In my '63 I had already moved to 20W50 conventional as I found that with 10W30 my oil pressure dropped at idle. With the 20W50 it holds at around 25-30 lbs. which is fine for that engine.

I prefer running the multi weight to strait 30 or 40. Better flow at startup, more protection at high rpm's run in a boat.

Just my opinions.

M3Fan wrote: I had a friend with a 1993 Jimmy with the 4.3 V6 and Vortech heads, all stock.

Yes, the GM 4.3 engine had Vortec heads heads prior to '96 but the V8's did not. 96 was the year GM started putting Vortec heads on the V8.

TRBenj wrote: 81nautique wrote: . Im afraid im uneducated on the pitfalls of high oil pressure- what are the drawbacks? Can you blow a seal or make the oil frothy/airy?

I don't really have an answer for you onthat Tim. Back when I was shopping for parts there was a thread that argued the High Pressure pumps build more heat. I talked to my engine builder and he contended the HV pump help draw heat away from internal engine components because of the higher flow of oil. He also said that was his opinion and unsubstantialed but he's been building engines for a long time. He and I selected most of the internals together, so far so good.

racintj wrote: TRBenj, I don't want to beat a dead horse, but does it bother you running the oil pressure with the 20-50. I just hate seeing that needle so high all the time, especially when 30psi is plenty anytime.

I dont know enough for it to bother me. I need to read up more on the subject to find out the drawbacks of high oil pressure. For now, if thats what Cam Research recommends, thats what I'll run.

BuffaloBFN wrote: Thanks Nutty and 90 Nutty, you said that GM went to roller in '96...does that mean that the '95 Tull mentioned is essentially the same motor I have in my '88 or did mercruiser match up different parts inside? Thanks again

Actually I can't take credit for saying that the trucks didn't get the roller 'til '96 (which is true for the most part). You can thank TRBenj and racinj for that bit a factual information. I did some research last night and this morning to verify and sure enough they are right. Except for a few exceptions, trucks didn't get roller cams til '96. Car engines started getting rollers in '87. The engine Tull mentioned is a big block so I don't know when they got them. Since the car engines had rollers and trucks not, I would assume they come from different assembly lines. So which one of those lines are the marine engines pulled from? I've always thought truck but I could be wrong. Or maybe there's a dedicated assembly line for marine engines. I called the Mercruiser Headquarters in Oklahoma. The tech I talked to gave me a part number for a cam for a 95 Mercruiser 5.7 Magnum Skier (which is the engine I have in my boat) but he couldn't tell me if it is a roller camshaft. I will make a few calls to dealership service departments and find out what I can and post the results.

Okay, I have made several phone calls to verious places including Mercury Marine, Summit and several other places that deal in marine engine parts. Here's what I've found out. If you want to be sure of what your engine came with (roller or flat tappet), right down your engine serial number and call the local dealership service dept. Give them all your information. In any given year from 88 to 97 (and maybe beyond) your marine engine (depending on model and serial #) could have either a flat or roller cam. Don't trust anyone who says that all of any particular model has a factory roller cam. Especially if it falls below a 97 year model.

nuttyskier2002 wrote: Part of the reason for the boat Tull mentioned being able to achieve 3000 hours was due to the electronic fuel injection. FI engines last longer due to better fuel atomization and more precise control of fuel and ignition.

I'm certain, but along those lines, I can add we've been skiing regularly behind a carburated indmar 351 powered 88 MC PS with 2900 hard hours, and no symptoms, tranny and engine have never been opened. There are always fliers in the distribution.

Munday wrote: My answer is yes,flat cam one lobe down another going when pulled apart.Mobil 1 1000 hour motor changed to Mobil at about 750 hours

Munday;

What weight Mobil 1 were you running at the time? I only ask because I'm a Mobil 1 freak. I've used nothing but Mobil 1 since the mid eighties in literally everything I've owned that is a four stoke. That includes lawn mowers and pressure washers. Never a problem of any kind. Mobil 1 website specifically states that the 15W-50 Mobil 1 is reformulated to include even more of the ZDDP additives for race and high performance engines that would require the extra lubrication. FWIW, I've run that 15W-50 M1 in my boat since I've owned it. That was at 450 HR's and now approaching 1300. Pressure is 40 PSI idle and never seen higher than 60. I also run probably 75-80% of the time at 4000 RPM or higher for my barefooting so I by no means baby this thing.

I plan on calling Mobil next week to talk to somebody to confirm and find out about the lesser weight oils. I'll post the results.

M3Fan wrote: I just ran my boat on 20W50 for the first time yesterday. Oil pressure was certainly high, between 60 and 80 psi the whole time. When the motor was completely warmed up, it would back down to around 45-50 psi at idle.

Thats about what I see right now with the 15w40. Glad to hear the 20w50 isnt much different. I swung by NAPA last week to pick some up- they didnt have any in stock but could order it... price was $5.70/qt! Did you find it any cheaper?

Yep, Autozone. Just over 3.00/qt.

Just happen to have a quart of VR1 20W50 here in front of me.

"Ashless anti-wear additives and ZDDP provide ultimate wear protection"

"API Services SM/SL/CD"

It does not say off road only. It may be the single weight oils that are marked off road, not sure.