gofastpilot

I wouldn't come down too hard on the guys up on the hill in Fond Du Lac. I had the pleasure of meeting 2 of their engineers during the Milwaukee APBA races. The amount of R&D that they claim to put into their power-plants is astonishing. Before they certify and market an engine for public use it gets a 50 point test which is extremal vigorous. They were very educated and would answer any question I would throw at them.

I am not an engine builder by trade but an enthusiast just like most of us on this forum and I do build my own engines. I felt kind of privileged to buy these guys a cold one!..............gofastpilot

John B

Dennis,
I am an engineer, and have worked for GM fuel systems, and have been in high performance motors most of my life, I tend to agree with you. Mercury reps are very nice people but they don't seem to have the expertise I had expected.
I have never owned a motor that looked like it burned coal until a bought 500 efi's and then my 525 efi's were worse. The 525 may finally have a service manual out almost one year after being introduced. The new Bravo sportmaster under performs the stock Bravo lower. And on and on, and nobody knows nothing.
How about 25 hour oil changes. You should never have to add oil because there is so much fuel in the crankcase and the oil is black after 10 hours. What about the 900sc, that needs a valve train overhaul after 75 hours for $10000 or more? What happened to the NEW 1050 sc?

Dennis Moore

Formulafasttech

If Mercruiser had a competitor like the American car manufacturers have the Japanese and European car manufacturers you would be singing a different tune.
The innovations and technology would be light years ahead of what we have now.

It must be a real challenge for Mercruiser products to win an offshore race! The guys at Lake X must have to really bust there butt to keep up with the competition! How much better would the Lake X guys be if they had the Germans or Japanese at Lake Y performing the same service and competing against them at every race? (probably not much better, but everyone would be going to Lake Y for their race products!)
Have you ever checked out the fierce competition between Ford, Chevrolet and Dodge in Winston Cup racing? How about the innovations and technology advances made every year between the motorcycle manufacturers when they race motocross against each other or the snowmobile manufacturers when they race snocross against each other?

You must be blind to think that Mercruiser technology is advancing at anything other than a snails pace. If there were any competition in this industry we wouldn't be paying $40,000.00 for boats with engines made from cast iron, with two valves per cylinder and camshaft-in-block technology. We would have aluminum engines with four valves per cylinder and overhead camshafts.

Dennis Moore

Dennis Moore

I get a kick out of people defending Mercruiser. Look at the way they are constantly trying to patch together a 15 year old design (Bravo) to work with 500 or 600 horsepower engines.

The Bravo uses Timken thrust bearings and needle roller bearings to control the forward and reverse gear thrust in the Bravo drive shaft housing. Even Volvos first drives used large ball bearings to stabilize the forward and reverse gear thrust. Volvo sets gears up by measuring gear backlash and checking tooth contact pattern. Ever here of a spec for measuring backlash on a Bravo drive shaft housing gearset? Tooth contact pattern checks?

Volvo isn't the answer either, but even THEY have motivated Mercruiser to change a little. Would we even have the outdated Bravo if Volvo hadn't shown the world the cone clutch drive? Lets not even get into the technology behind the Alpha drives.

None of the modifications to the Bravo have come from Mercruisers leadership in the sterndrive business but have come from the aftermarket. The Bravo still wouldn't be any different today if the aftermarket drive parts manufacturers like IMCO and B-Max hadn't started to improve the product. Mercruiser has copied them step for step. No leadership there!

There is no doubt in my mind that if anyone, with a little financial backing, started to build a production drive for high horsepower engines, (it wouldn't be difficult to build a better drive than the Bravo for the same price). most people, including myself, would switch to the new drive in a heartbeat and never look back.

Mercruiser has the resources to build their own engine, remember the four cylinder 470? What a joke that was!
They manufactured the sophisticated Corvette engine from casting and machining to assembly all in the Stillwater plant. They could manufacture a fine marine engine if they had the engineering and motivation.

Dennis Moore

Adivanman

Dennis,

You obviously have an issue with Mercury that has left you more than just a little bit bitter...perhaps they shunned your advances or balked at you informed suggestions in the past.

It is a relief, however, that you can rationalize (at least in your own mind) your criticisms. The fact that you are profiting from doling out advice on how to build the big and small block chevrolet engines while lamenting on their obscelence is hypocritical at best...In your own words:

"If there were any competition in this industry we wouldn't be paying...for boats with engines made from cast iron, with two valves per cylinder and camshaft-in-block technology." DM

Now, I have not read your books (nor do I plan to) but I would assume that you do not offer anything which is earthshatteringly different.

Moving beyond what appears (on the surface) to be a combination of adolescent penis envy and sour grapes from the mechanic to the engineer, perhaps you would like to enlighten us on why there is no competition for Mercury in North America (or elsewhere) in technology if not in brand name. In terms of gasoline powered end products, large block GM engines dominate - regardless or color or name brand - Merc, GM, Volvo, etc. No-one else has developed (or expressed an interest in developing) an alternative gasoline burning marine engine in recent history.

Your analogy to modern automobile technology aptly demonstrates your limited point of view. You criticized the 900SC - please enighten us as to how many all aluminum, overhead cam, multi-valve engines it takes to produce 1000 foot pounds of torque on 87 octane pump gas...that's alot of drives!

After being called on your criticisms with respect to engines (and not being able to counter the specific point made by HT and FF) you complain about drives. The same arguement applies. Who has (successfully) stepped up with a viable alternative? Mercury has many drives capable of handeling higher HP applications, it is the boat manufacturers that continue to mate high HP with borderline drive packages. This is not a fault of Mercury...what does this have to do with Mercury?

I could go on and on but I don't see the point. You make money, you earn your living saying that you are a Mercury Master Technician (don't get me started on that) yet you offer nothing positive - regardless of the facts. If it's not engines, it's drives. If it's not drives, it will be props.

You have an axe to grind, grind away - just try to keep the hypocritism to a minimum...

Just my 2 cents.

Adivanman

Formulafastech,

Thank you for the link to the ZR1 article. I think that everyone would benefit from reading it, as it provides a unique insite into the work that Mercury puts into building their engines.

35/25

RickR,
looks like you started a war here. To get back on the original topic:

Yes, the 168731 cam card states a 107 intake centerline.
This cam is ground on a 112 degree lobe separation angle. However, if you install it using a conventional timing set and align the timing marks on the two gears (ie; installing it "straight up"), the cam would end up with the intake centerline at 107 degrees. This is because Crane grinds most of their cams with 5 degrees of advance. Without the built-in advance, a straight up intallation would put the intake centerline at 112 degrees.
The same holds true for the 611 cam. It is ground on a 110 LSA and with the 5 degrees of built-in advance, the intake centerline is 105.
You didn't mention what size motor you were thinking of putting the 611 cam in.

Rich

RickR

35/25
611 cam is for a 502 built similar to Merc's HP500 but with appx 9.5 compression. Max RPM 5500

I was asking if a 109 Intake lobe centerline would build more power in the high end. Low end torque is no problem (engine is going in a 22 Classic Donzi)

35/25

I would think it should make more top end power at 109 than at 105. How much more is hard to determine. My guess is probably not more than 8 to 10 horsepower either way.
But with iron heads and 9.5 CR, it might be safer to run it at 109 anyway. This will keep the cyl pressure lower and minimize the chance of detonation. Unless you already have the 611 cam, if you are more interested in top end and don't need a bunch of low end, a slightly bigger cam with a 112 LSA installed at 109 or 110 might work better for you.

ursus

Mercruiser Master Technician ,,,I guess that would mean your qualifications are what,,, you got an A+ in them courses taught by the forklift drivers and warehouse workers