parnelli(rc)jones

I had a Procharger installed on my 2005 496 Ho last year, I set it up with 5 psi. of boost. I couldn't get the stock pcm and fuel to supply enough fuel to run the boat. I spent the hole summer trying to tune with different injectors and playing with different fuel presures. I couldn't get the motor past 3 to 3.5 psi of boost with out the gardian going off shutting down the power. I bought Arizona Speed & Marines wiring harness and the MEFI 4 computer. I got one run at the end of the season the motor ran great and got 5psi. of boost, but now I'm getting alot of presure in the crankcase. Does anyone know if there is some sort of ventilation like a pvc on this motor? It seem like that the procharger is pumping air into the crankcase from somewhere and I can't seem to find out where. When I run the engine at 1500 rpms and take the oil filler cap off I can feel cool air blowing out and if I put my hand over the the filler tube to block the air the engine jumps up to 2500 rpms, Any thoughts? The engine runs really good and doesn't have any missing going on so I don't think there's any internal damage. Has anyone put some sort of crankcase evacuation system on marine engines? If so how should I go about doing it. Any thoughts would be greatly appreciated for the guy that installed the system is of no help and I just want get on the water and have some fun. Thanks Stu

800XCR

iTrader: (2)

You most likely have detonated it causing "blow by" - (Internal damage) and will be looking for pistons very soon. I suggest a leakdown test to verify engine integrity and pull it apart before it really breaks if so indicated.

There are a couple of guys that can help with the stock calibration as well as the mefi 4, but you need to spend the money to put it on a dyno and have it done. Best wishes and let us know.

articfriends

iTrader: (1)

I second xcr800-before you waste any time doing anything else get a leakdown test done to see if you have a hurt piston or rings. With "Blowby" as bad as your describing I wouldn't be surprized if a ring land is missing down to a ring or something,cast pistons can't take but a few seconds of detonation,Smitty

LAKESIDE RESTORATIONS

I am a distrtibutor for procharger. The 2004 & up 496 engines are not supposed to be procharged. There are Too many mods to do to the fuel system, Ecm, pistons, etc...

A Procharger could be done on it if you were willing to do all of the mods & conversions required to currently make it boost properly. The thing is it is not currently very cheap. To do it properly from a Pro shop you could probably expect a bill considerably more than the current Procharger 496 kit. Mainly because you would end up replacing expensive fuel system components, pistons, etc.. etc.... As well as the labor by someone educated on what they are installing.

Btw.. One of the reasons I know this is I have an 06 Mag Ho in my Donzi as well as a few clients with newer models also that are also willing to do it. However I'm not currently planning on moving forward with it yet until I can find a "good" way for this to be done reasonably & properly..

Jamie / Lakeside

Turbojack

Does not sound good. Do a leakdown test or at least a compression test. I can not explain why your rpms go up when you put your hand over the oil filler.

Cobra1

I learned the hard way that you must change your pistons and fuel management. I blew mine up with 3 lbs of boost. Its only a matter of time before it happens to you.

BadDog

You guys are a buzz killer for his first post! Good advice and likley sound. Bad news is never easy to take.

LAKESIDE RESTORATIONS

Your right... I'm sorry I had to be one of the bearers of bad news.. I just dont want to se the guy get further misled or have more problems than he already has.

To the individual with the 496 procharger problems feel free to call me during our business hrs. I may be able to give you some Ideas and answers.

Jamie / Lakeside 570-639-2628

Raylar

Just from our expierence I can say that supercharging a stock 496 will in most cases eventually lead to stock piston failure. Pro-Charger seems to be ahead of Whipple in the race to see who can grenade the most stock 496 motors.
My forged piston sales have never been better!
There is a reason Whipple superchargers grenade less 496's than Pro-Charger. The reason is Whipple reprograms the ECM which is an absolute must and Pro-Charger does not. However, even with ECM reprogramming the stock 496 cast piston was designed and built by GM for emmissions compliance. To get the big bore long stroke motor to meet stricter emisson standards the piston is designed and built with only a .090" top area over the top ring. Couple this thin area with a intake valve pocket that extends all the way to the outer edge of the piston top deck and you have an inherently weaker area in the top of a cast (brittle) piston that when fuel and spark delivery aren't just perfect under boost conditions, some detonation occurs that is sometimes exaggerated because of lean fueling and WHOLA! piston top breakage that leads to serious and sometimes catistrophic engine destruction. Whipple and Pro-Charger both make excellent parts and supercharger systems. The problem here is not the superchargers or boost, the problem is boosting on top of a piston that won't hold up in the marine high load use! This piston was designed for a naturally sspirated use and holds up quite well in those uses!
If one were to refit the block with forged SUPERCHARGER pistons, rework the fuel system to deliver the proper amount of fuel at all conditions under load and re-program the ECM accordingly with measured air fuel ratios, the superchargers will work very nicely. There are many boaters who have supercharged 496's with good internals and are making over 800HP with decent reliability.
You also need to keep in mind that a supercharged big block motor will generally not run the long hours like an equivalent size normally aspirated motor. Just remember that big power added to any motor is not going to be cheap or easy!
There is really nothing wrong with STOCK block 496's, they just should not be supercharged or have their components pushed harder than their design maximum, just like any other stock block motor!
Hope our direct expierence here helps educate more OSO'ers that supercharging is a high performance science that requires careful setup, very strong parts and quality engine building techniques.

Ray @ Raylar

Lab

Parnelli, -some years ago I had the same problem with a procharged 496, - the boost entered the crankcase.
It showed up that the that the intake had a ventilation tube (steel insert) between the plenum and the crankcase.
Blocking off (welding) the passage the solved the problem.