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fattee
06-02-2001, 12:04 PM
I heard horror storries about a pro charger set up, of course if you only use the boat once in a while it would be fine, but what about a daily crusier, and skier, wouldn't i be safer just to bulild a 502 with cam, header, carb mod, and or some head work, would i be more relibale, and what about a 454 or 496 with the same mods, I know 502 are getting hard to find,if i could snag one should i grab one now or just wait until the per-fect the 496 I have heard they are still working out the bugs, what are your thoughts, Thank you

Jeff
06-03-2001, 09:01 AM
I just bought a new 502/502 this past winter for $5200 from the local chevy dealer. I don't think you will see a drastic shortage of these performance crate motors for awhile. You just won't see them being installed in new marine applications is all. I would go for the 502 you can buy it from chevy as a assemmbled motor or partly assemmbled or just a short block. The thing to remmember is that to shop around different dealers ask different price on the same part number I found out. So shop around.
Jeff

RIVERTIME
06-03-2001, 07:49 PM
Is there any modifications needed to convert that motor over for marine use? That sounds pretty good considering Mercury charges I think over $15k?

ponponracing
06-03-2001, 08:33 PM
Yes there are. That's why some people make a living of preparing marine engines. Otherwise, everybody would buy those crate engines and run them as they are.

Havasu Hangin'
06-03-2001, 09:47 PM
Originally posted by ponponracing:
Yes there are. That's why some people make a living of preparing marine engines. Otherwise, everybody would buy those crate engines and run them as they are.
Hey ponponracing,
Could you do me favor and outline the specifics of what you are referring to with regard to marine engines?
From what I understand, for many years, Mercury has had a close business relationship with GM, which is why you see very similar products between Mercury and GM's truck division. Correct me if I'm wrong, but GM engineers have even looked to Mercury for recommendations on future product development.
Historically, the GM truck division and Mercury marine engines have had the same goal- to develop torque for engines that are under heavy load (constant load in a marine enviroment- no gear reduction and heavy resistance). Hence, the marine engines had the beefy internals such as forged pistons and crank, etc. as thier truck division counterparts do as well.
However, back to my original question. Aside from the bolt-on Coast Guard approved necessities (marine fuel pump, carb, flame arrestor, fuel filter, steel fuel line, marine alternator, etc.), what separates a GM crate truck engine from a Mercury long block? What do you mean by "preparing" a marine engine?
Just curious. Thanks.

Racing Ray
06-04-2001, 04:45 AM
.
[This message has been edited by Racing Ray (edited March 12, 2002).]

ponponracing
06-04-2001, 05:50 AM
Ray is right. But if you take a stock GM 502 apart, you will be amazed at how those engines are prepared. In a car or truck, how many times will you go really wot, unless you race the thing? So, the way they are set, they will give good service in a normal use.
In a boating day, quite everybody go wot for quite a long period of time, any reason being good to do it. So the engine as to be prepared as a high output engine that will be severly used. Every internal part of it has to be put in place with attention and inspection, not like it is on a production line.
GM crate engines are designed to be use normally, mostly in a car or truck.
You know what they say? "If you want to kill an engine, put it in a boat".

Havasu Hangin'
06-04-2001, 06:33 AM
Hey ponponracing,
I have a couple questions regarding your previous post:
Originally posted by ponponracing:
[B]But if you take a stock GM 502 apart, you will be amazed at how those engines are prepared... So the engine as to be prepared as a high output engine that will be severly used. Every internal part of it has to be put in place with attention and inspection, not like it is on a production line.
[B]
1. Does Mercury take apart the crate engines they get from GM?
2. If so, what specifically do they do with regard to "attention and inspection?"
Perhaps you can share with us some of your experiences regarding "how those (crate) engines are prepared."
Thanks again for your help.
PS- Thanks Racing Ray for the catch on the brass freeze plugs.
[This message has been edited by Havasu Hangin' (edited June 04, 2001).]

ponponracing
06-04-2001, 08:52 AM
Havasu,
on this forum, I try to help people who need help by sharing info. from my past experiences. I won't get involved in topics where people want to save money by working on their rig to save a few bucks.
There are also things I can say and others I won't say. I feel I'm lucky to be able to speak with nice people from different enterprises, and I know they help me because I ask them and they know what they tell me stay in my brain.
I'm a professional engine builder and there are things I can tell and others that don't need to be told. If I start telling people what I do on 502 to make them give performance and last,I'm better start writing books to try to make money. From a stock crate 502, I did a couple of nice combinations that surprised me with torque, horsepower and reliability.
So, my answer to your question is that I don't know if Merc take those crate engines apart and if they do, what work they do to them.
That's my best with your question.

Racing Ray
06-04-2001, 09:45 AM
.
[This message has been edited by Racing Ray (edited March 12, 2002).]

Havasu Hangin'
06-04-2001, 11:16 AM
Thanks, Ray. That's what I was looking for. I suspected the deck and bores were questionable. In my opinion, head work is always a necessity as well, as heads and flow are soooo important.
Bottom line, Jeff, you would be wise to consider blueprinting and balancing on any crate motor. Still cheaper than the Merc long block.
The 496 is a complete re-engineer. Do I have to re-learn 1-8-4-3-6-5-7-2?
PonPon- I apologize if you took my questions as trying to pry trade secrets out of you. As you pointed out, this forum is about sharing information and experiences. Who has better information and experiences with motors than a professional engine builder? In fact, if you look at my questions closely, they give you the opportunity to share your experiences without sharing your horsepower or reliability recipes.
I don't think anyone would be on this forum if they had an unlmited budget. I myself often "try to save a few bucks." Yes, I do work on my own rig. However, I do rely on a professional engine builder for my horsepower needs. Although price is important, credibility goes a long way toward my decision.
Thanks!

ponponracing
06-04-2001, 12:56 PM
Havasu,
I didn't feel "invaded", and I'm sure you didn't mean to sneak into my secret engine formulas (!!!!!). I just meant that there are things you can't tell everyone. I don't know you, you don't know me.
I simply felt you were asking a little too much for a public forum. And if I talk about what is going on in companies like Merc or GM, I'm not sure they will appreciate....
Also, I didn't mean that people working on their own rig are cheap, some people simply exagerate in their request.
Ray is right again. There is good torque and power in 502s. And they stay together for a pretty long time if they are put together the right way. The combination I sold the most the past few years is crate 502s (short block), unleaded gas, single carb, normally aspirated, cast iron heads, 650hp, 628pds of torque. Those engines work good, idle good, shift good and look good. I'm not in love with everything in those short block, but it does the job.
Dyno sheets on request, no cheating.

boatnam1
06-04-2001, 01:05 PM
hey havasu hanging,i dont know if your looking for a complete motor or just a long block.but i can tell you from experience to spend a little extra money.have a engine builder build it that knows what he's doing.iv'e been through three motors.i wont mention any names but two advertise in hot boat.the motors i thought were built good were junk.i didn't really get to see exactly was i was getting because i trusted the builders and never really bothered to go take a look at the motors while they were being assembled.but after the second one blew,i took it to clay smith in anaheim and gorge the owner disasembled the motor in front of me and showed me what junk looked like and what one of his motors looked like.whew what a difference!the care he takes in building a motor really made me feel comfortable.the boat is blown running 13 pounds boost.this is the second summer on the motor and it runs so good.i just wish i would of taken this route from the beginging.this is kinda a long explanation about building a motor but if it saves one person from going thru the trouble and money i went through it's
worth it.so instead of a 502 chevy crate motor.get a block take it to someone that knows what there doing and you can build a nice motor with all the hard parts for just about what you can buy a crate motor for.you will be so much happier that you did especially if you plan on srewing the motor really hard.good luck boatnam1

Havasu Hangin'
06-04-2001, 01:34 PM
Hey boatnam1,
Thanks for the heads up, but you're preaching to the chior- I've been down that road (or river)- maybe someone else can learn by our mistakes and save some money in the long run.
Last year my old motor quit- I thought it needed a tune up. When I pulled the #3 plug, it was shredded. Oops, broke a piston.
It was the first three posts that were motor shopping.
I am familiar with Clay Smith- great reputation. I actually spoke with George awhile ago as I was shopping for a cam. Very down to earth and helpful.
13 pounds? Brutal!

dcraig
06-04-2001, 02:23 PM
From a block standpoint, is it better to start with a 454 or a 502 in term of reliability in a blown application? Do the siamese cylinders of the 502 present any problems?

fattee
06-04-2001, 04:38 PM
Originally posted by fattee:
I heard horror storries about a pro charger set up, of course if you only use the boat once in a while it would be fine, but what about a daily crusier, and skier, wouldn't i be safer just to bulild a 502 with cam, header, carb mod, and or some head work, would i be more relibale, and what about a 454 or 496 with the same mods, I know 502 are getting hard to find,if i could snag one should i grab one now or just wait until the per-fect the 496 I have heard they are still working out the bugs, what are your thoughts, Thank you
I am still waiting for an answer to my question, it looks like everyone got side tracked... and no one responed about the 502 vs the 496.. And what about availbilty in a jet application... Lets try again.. THank you

fattee
06-04-2001, 04:39 PM
Originally posted by fattee:
I heard horror storries about a pro charger set up, of course if you only use the boat once in a while it would be fine, but what about a daily crusier, and skier, wouldn't i be safer just to bulild a 502 with cam, header, carb mod, and or some head work, would i be more relibale, and what about a 454 or 496 with the same mods, I know 502 are getting hard to find,if i could snag one should i grab one now or just wait until the per-fect the 496 I have heard they are still working out the bugs, what are your thoughts, Thank you
I am still waiting for an answer to my question, it looks like everyone got side tracked... and no one responed about the 502 vs the 496.. And what about availbilty in a jet application... Lets try again.. THank you

Havasu Hangin'
06-04-2001, 05:54 PM
Sorry about getting sidetracked- my bad. I kinda instigated the whole crate vs race prep vs Merc topic. Your answer is in there, it's just buried a little.
In my opinion (I'm not a professional marine mechanic), a Procharger setup can be used as a "daily driver" if you keep the boost down (5 pounds or so) and get a good oil cooler. You will probably only get so far (with a good idle and being reliable) with a naturally aspirated motor. A blower can be used to take you to the next level, but there's a price.
Jeff is right on the track on the 502. Lot's of good aftermarket goodies available. Not sure that's the case with the new (re-engineered) 496. The firing order was changed for a smoother idle.
dcraig- I'm not sure about the siamese cylinders- good question. I remember that used to be a concern, but I don't hear about it much anymore. Perhaps there is a mechanic out there who can address it. boatnam1 is running a 502 with 13 pounds of boost- lot's of testasterone in that boat.
My advice would be to ask yourself the following questions
1.What speed and function do I want? Skier?
2.How many ponies and ft/lbs to get there?
3.How much I have in the budget (AKA how much will my wife let me spend)?
Those are the factors I would look at if I were considering to Procharge or not to Procharge. Ray's experience shows you can probably squeeze 600 ponies and ft/lbs out of that 502 without supercharging, and still be fairly reliable. PonPon also was getting over 650 horses and 628 ft/lbs with his 502s. Those are with iron heads. Still need more? Then a blower is probably in your future.
My friend Procharged his 454 MPI, and that thing became a rocket. Of course, he spent over $9,000 (steeering and drive upgrades too) as he was now near triple digits, with 8 pounds of boost in a 22' cat. Idles nice, but a little fast with the 30' prop. Your case is a little different, as I am assuming you have a clean sheet to start with (no short block?).
I can't help you with the jet application- I have an egg beater.
There's my 10 cents- good luck!
PS- we really just wanted to get the "flaming folder" icon.
[This message has been edited by Havasu Hangin' (edited June 04, 2001).]

ponponracing
06-04-2001, 06:14 PM
I'll try this answer. To me, if you build a 502 with all the parts you mentioned, you can get between 500 and 600 horses. If that's enough for you, there is no doubt in my mind that it will be the simpliest thing to do.
By putting a Pro-Charger, you help filling the cylinders with a compressor. If the engine is build for boost, it should give you good service. If you start from a stock 502, with no modification, severe usage can be touchy. The P-C is supposed to be installed on a stock engine to give you instant power. And that works. A stock 502 has a stock compression ratio of 8.8 to 1. Meaning that it is O.K. on regular gas. When you use boost, the main effect is that you put more in the cylinders, increasing the comp. ratio. With a normal blower, you would be in trouble with almost no boost. The P.C comes with a chiller, the gas is also cooled, and that's why the motor can take more boost without breaking. If you start with a smaller 502, your chances of not hurting your engine are better than if you start with a 502-502, because the 502-502 already use components (heads, intake manifold, camshaft)working to fill up the cylinders more than the stock low output 502. In this way of thinking, the nice components of the 502-502 act like a blower: they help filling cylinders.
If you want your engine to develop more power, then according to me, it should be prepared for that purpose. P-C sale different power options, and with the smallest (the one that give less boost), you will probably have fun, as long as you didn't start with the biggest 502.
It is for sure that you will have to tune the motor according to P-C's recommendations.
If you spend the whole day on maximum boost, I'm not sure your engine will last for a long time. If you occasionally use all the power the blower can give, it will probably last longer than you expected. The problem with longer period of use is the heat involved. If you are always on boost and the engines components are not prepared to receive that extra heat, you might see parts breaking or detonation. If you stay on boost for shorter period of time, heat doesn't accumulate as much and by going back on non boost situation, you let the internal parts come back to a normal temp.
You can also help the motor by using better gas.
So you have my opinion about what you asked. Before you take a decision, evaluate what power you want from your engine and evaluate yourself as a boat user. More power involve usually more money. A system like Pro-Charger or whatever the brand can give you good power numbers for a lot less money than what's involved in a non-supercharged, non- turboed,or non-nitrous engine. But you have to use it with your head.
I keep saying that the only thing that stop people from acting dumb with their engine is what it cost to fix them. I can't help you with the new 496 since a never touched one. A 454 will give you less power than the 502 and the internal parts being of the same quality, it should last longer than a more powerfull engine. Of course we are not talking about the old 454-330 that I wouldn't really considere for high-perf.
This is just my opinion. I won't be offended at all if you read other people's opinion before taking a decision.

ponponracing
06-04-2001, 06:20 PM
fattee,
why don't you read the next topic in the same page of discussions?

ponponracing
06-04-2001, 06:33 PM
Sorry to write again. It takes me so much time on the keyboard that when I'm done with my text, I see other discussions.
I built and rebuilt many siamese BigBlock Chevy and there was never any problem with the cylinders being siamese. Doesn't mean there wasn't any problem with those blocks.

Jeff
06-05-2001, 03:14 AM
The ZZ 502 does come with marine head gaskets (they are stamped on the gasket) it does come with brass freeze plugs. I did remove the stainless street & stip valves and replaced them with inconel valves. My aluminum heads were cnc machined new, plus I had alittle extra head work done. This motor was bought for the intention to be blown. I have spoken to Bob Endress (bad spelling I know) he told me that 4lbs without a cooler would be no problem as the aluminum heads dissapate heat so well over iron heads. More with a intercooler. An engines life span depends on how hard you run it and how high you spinn it. I think we all know that. I also have a Indmar 350 and so far their are no trick parts (marine) in that engine. It looks like a 350 goodwrench engine inside to me with stock GM shelf parts. Huuuuummmm!
Roosters To Ya
Jeff

jsblendorio
06-05-2001, 04:33 AM
I had one of the 502 HO crate engines with iron heads (450hp). Changed the freeze plugs to brass major $15 upgrage. Added a marine carb, flame arrestor, MSD marine box with a pro billet distributor. I upgraded to roller rockers, but left everything else as is. It ran like a charm for the last three years. I just sold the boat, and would swear by it as a budget motor for under $5K.
I know the engineers ar mercruiser, and they buy the same long blocks. They change the cam, freeze plugs, valves and intake, (MPI of course). The only complaint I had was that it burns oil, but when I checked the Mercruiser service manual, it states that "it is not uncommon for big block high performance engines to use up to 1 quart of oil in 1-5 hours if the engine is operated continously at the upper end of the RPM range". So I just kept oil with me and checked it each time I took the boat out. Not a bad habit to get into anyway.
John
[This message has been edited by jsblendorio (edited June 05, 2001).]

fat rat
06-05-2001, 05:39 AM
I also had a 502 Gen v crate with the same upgrades, plus a lunati cam part# 00024...but ran it in a jet boat for 4 years never left me stranded and a solid 75 mph (gps) @ around 4900 rpm. It got excellant fuel economy compared to my 330hp 454, I quess you attribute that to a more efficient motor. The motor cost me $3900. plus upgradesand sold my 7year old Hardin Marine to an I/O guy for $2000, the math isn't diffacult on this one. Just my $.02..Happy Boating!!!!

fat rat
06-05-2001, 05:57 AM
Sorry for the double post....But I got a 510 BBC (502 mark iv) going in a new 21' Daytona Jet. The motor was proffessionally built and dynoed, equipped with the following 2 Nick 750 holleys, 8-71 Littlefield, alum bow tie heads worked by Total Flow, JE 7:8-1 and so on.....when I read about all the problems and the horror stories, I get the jitters when I just think about launching this thing for the first time. I'll let you all know how it goes when I get it....should be soon.

froggystyle
06-05-2001, 09:36 PM
Fat Rat. I hope you launch it soon, because summer is starting, and you will have one hell of a ride! I just did a very similar setup in my 19' Daytona and am totally in love with it. I am such a big supercharger fan now it is barely believeable. Talk about horsepower per dollar ratio! Very few dollar increases are involved with building a blower motor over a stout non-huffer, and the payoffs are huge. Run of the mill Rect. Bowtie heads, forged everything, a solid fuel system with two 750's and a cam setup for the job have given me close to 900 hp on an AV gas mix with great manners. I'm obviously downplaying the effort that went into the setup by my builder, but how the hell else are you going to build over 750 on pump gas and reliable. Basically, it was $3K for the BDS blower, and an extra $400 to set up the holleys. Money well spent. Have a great summer!

ponponracing
06-09-2001, 03:47 AM
Froggystyle,
how many cubes and how much boost in your motor?

froggystyle
06-11-2001, 12:01 PM
468 and 10#. 781 Heads with big stainless valves with Crower springs, retainers, rockers and pushrods. Don't get me wrong, it's a good solid combo, but most of the expensive parts you would have added to any high performance engine, that they are just different, not more expensive was my point.
The only thing I really had to suck up over a "normal" motor was the fuel system. I ended up running a BG 400 with all the assorted bells and whistles that require upgrading with such a large pump, but I feel that it may have ended up being overkill...

fat rat
06-11-2001, 04:13 PM
Hey froggy, thanx for the positve responce....I'll let you know when I get it out for the first time...can"t wait. If you get a chance for a Duty Station change to the right coast.......come on over, and bring your boat.

sea buddy
07-19-2001, 04:23 PM
merc does not openup a chevy motor. Changes are done by chevy, except stroker 6.2, see the price they have to charge per hp to cover their costs. Crate motor is different in head gaskets, etc. You can not buy the merc spec engine from chevy, at least that is my knowlege.