Water pump hitting timing cover. Help!

[Fix'em]

Hey guys. I'll give you a quick background to my problem here.

I am replacing the 4.3 block in an 88 Thundercraft. The previous owner made the fatal non-winterizing mistake of not draining the block, and, well.... you know the rest

So I was able to get a very cheap block from a 97 Astro van. I stripped it bare and prepped it, reconditioned the rotating assembly from the original Merc. 4.3, and started to transfer everything into the donor block along with new Merc bearings, pistons and rings. All went very well.

The only small snags I had encountered until last night were the fact that the oil pan and timing covers are different on the newer block and I had to use those from the newer truck application instead. Not a big deal.

However, once almost all back together last night, I went to put the water pump on the front and hit a bigger snag. The newer composite timing cover has a different contour and sticks out further than the original steel cover, so now my water pump wont mount. On the starboard side, the pump outlet hits up against one of the cover bolts and is about 1/2" away from seating on the block.

My current solution to this is to make 2 spacers (one for each side) to space out the pump equally and pull it away from the cover to clear. However, then my belts will not line up, so I will have to also make spacers for the crank pulley and the altenator and power steering pumps.

Can anyone else think of another solution. Is there possibly a different water pump from a newer application that is made to clear the composite 1996 - 2000 timing covers that I could use?

Any help or suggestions would be appreciated guys.

Thanks.

 

[JustJason]

Re: Water pump hitting timing cover. Help!

there are 4.3 gen 1 and gen 2 motors.... and the are a bit different. I don't know what one you have, what one you had, and what one your ordering parts for but it almost sounds like your mixing and matching bolt on's and brackets. I also don't know the year they changed.
Does your new block have a balance shaft? If it does the only way you may be able to get it to work is to order or fabricate all new brackets for a gen 2 motor.

 

[Fix'em]

Re: Water pump hitting timing cover. Help!

Well, unfortunately, it's is already a bit of a mix and match situation. The original engine was already replaced due to a freezing mistake a few years ago. This was apprently the guys second time cracking a block. It was apparently a 95 Vortech engine. Both the engine I took out and the replacement block have a balance shaft.
However, the damaged block had a wider timing cover flange made for the pre-96 metal timing covers. My 97 block has the thinner flange and less bolt holes for the composite timing cover. Had I known, I would have searched for a 95 block, but now it's too late unfortunately. Everything is back together except the water pump.

Does anyone know if a 96 or newer Merc. engine used the composite cover or did they continue to order and use the older style blocks?

 

[Fix'em]

Re: Water pump hitting timing cover. Help!

Well, you could replace the impeller in the water pump that came with the engine and use it. You need to go to either a bronze or a stailess steel impeller to prevent it from corroding away.

I had thought about that as well, but when I compared the water outlet size, the truck pump is MUCH smaller. I don't think it would supply enough volume.

 

[Bondo]

Re: Water pump hitting timing cover. Help!

Does anyone know if a 96 or newer Merc. engine used the composite cover

Ayuh,... Mercruiser buys current production motors,....
But,...
Who knows how much re-engineering they did to make the new 1s work....

 

[Fix'em]

Re: Water pump hitting timing cover. Help!

Yes it will.

I would bet that if you compare the two pumps their Gallon Per Minute rating is not that different.

Dang. Unfortunately that was an exercise in futility. LOL

I got the original pump from the truck engine out of the parts pile, sandblasted it, painted it and mounted it to the fresh engine. Only problem is, the pulleys were not interchangeable from the serpentine to v-belt. The mounting flanges are completely different. And, also, although the pump now clears the timing cover, the pulleys are almost a full 1" out of alignment meaning I'd have to make huge spacers for all the accessories still.

So, looks like it's back to square one. With the Merc original pump, and need ing to make 1/2" spacers for everything including the pump itself.