I'm currently doing a teardown on a 455. The timing cover has near perfect mating surfaces and all passages and ports. The problem is behind the water pump where there is some pitting and a circular gouge, obviously from a bad pump at one time. Is this going to cause a problem with flow? Any experiences with this problem? Am I going to have to put this on my Christmas wish list?
What you most likely see there is erosion mostly brought on from cavitation behind the water pump. The rotational forces the impeller places on the fluid cause bubbles to form in the fluid. Same thing happens behind a propeller on a boat or a ship. After thousands of miles and maybe some week antifreeze that cover starts to erode from the bubbles. I have two covers - one has about (guessing) 180k miles on it that I'm currently using - has some of this erosion. My other cover (saving for a later day) has only 40k miles (confirmed) and has no erosion on it. Cavitation is also promoted by low system pressure so a weak radiator cap can also accelerate this process. Submarines can go faster and remain quieter the deeper they submerge. The increased water pressure inhibits cavitation, and therefore, noise from all those bubbles. If the cover gets too thin or gets a hole in it behind the pump you do have to ask yourself where the coolant will go.
Cavitation! That's the word I couldn't think of. The cover has quite a bit of metal still left behind the pump so I'm goint to use it as is for the time being. If it gives me problems, I'll change it down the road. Thanks.
Just keep in mind that if it ever wears through that all the coolant ends up in the oil pan. EEEEEEWWWWWWW!!!!!!!
when my water pump died it ate into my timing cover on my 350 (simmilar design) 2 months before it was nearly perfect there with no rubbing at all. isnt there room on the back side to weld some new material? Nate
The cover behind the pump has a lot of contours that are cast in and would be hard to duplicate. I imagine if someone had the patience and expertise, it could be built back up and ground. With the price of a new cover, it may be worth it.
