Repowering 33 Outlaw
01-26-2003, 09:14 AM
#31
I spent a few hours in the GIL shop just before they were purchased by Corsa.
They could prove the gils were outperforming (ever so little) the CMI.
Merc put a fair amount of $ into CMI. Let's face it they look better. The problem is the tube length is not long enough nor matched!!! They do not out perform the GILs
As for a taller riser, the cam profile and length of riser before the water enters are a direct correlation on reversion. Overlap of the cam (where the intake and exhaust are both open) cause a sucking effect in the exhaust that brings water back into the engine at idle and therefore rust. If the engine idles most likely it is OK.
Yes there are other factors as far as engine attitude and taking waves in the aft where water flows back through the exhaust pipe to the engines. Good flappers take care of the later. These are really just secondary items.
What this effect has to do with weak valve springs I'll never know.
The HP 500 is a great engine. Valve springs can be replaced in a matter of a few hours.
Merc is great at correcting problems in subsequent versions, but they will not take care of the mistakes they have already made. Lots of older 454 Mags out there with solid cams. I tore a lobe off after 200 hours. I also noticed 2 partially broken springs. A few years later model a roller cam was standard and different valve springs. Imagine that!!!!!
They could prove the gils were outperforming (ever so little) the CMI.
Merc put a fair amount of $ into CMI. Let's face it they look better. The problem is the tube length is not long enough nor matched!!! They do not out perform the GILs
As for a taller riser, the cam profile and length of riser before the water enters are a direct correlation on reversion. Overlap of the cam (where the intake and exhaust are both open) cause a sucking effect in the exhaust that brings water back into the engine at idle and therefore rust. If the engine idles most likely it is OK.
Yes there are other factors as far as engine attitude and taking waves in the aft where water flows back through the exhaust pipe to the engines. Good flappers take care of the later. These are really just secondary items.
What this effect has to do with weak valve springs I'll never know.
The HP 500 is a great engine. Valve springs can be replaced in a matter of a few hours.
Merc is great at correcting problems in subsequent versions, but they will not take care of the mistakes they have already made. Lots of older 454 Mags out there with solid cams. I tore a lobe off after 200 hours. I also noticed 2 partially broken springs. A few years later model a roller cam was standard and different valve springs. Imagine that!!!!!
