circ pump or crossover's
 

building two new big block's should i keep the circulating pump's or go with crossovers. :cool-smiley-027:

Circulating pumps are good for stock engines- in fact, it allows them to run better and last longer since you get them up to a proper operating temp- no chance on running cold and scuffing parts thru tight clearances. Blower motors need lots of water volume to stay cool so the circ pumps will hinder you. The systems with crossovers and stats are a good compromise.

Remember, removing the water pump removes one more mechanical piece that can fail & strand you.

If you do alot of idling and not going over 400 horse, I'd keep the pumps.

crossovers
 

i removed the circulating pump on my older boat w/525sc type motor and pput a crossover on it and it works well,keeps the temps down.i wanted to put the same crossover on another boat i own w/502mpi mag and was told not to.my engine guy said the engine will run cooler and mess up the engine or would not run right because of the motor is computor controled.hope this helps.

circ pumps

Yes, EFI is much more sensitive to engine operating temp.

I'm going Back to Circulating Pumps, I've been told numerous times that you can get hot spots with cross overs.

And you can prevent that with Circulating Pumps.
Down side is they may not look as cool, but I did find some nice Billet ones. Check the link out.


http://www.meziere.com/displaycatego...32,232,397,175

Jon

thanks, i will stay with the circ. pump's. i shouid be at 450-500 hp on these 468's and my engine builder said use circ. pump's

I have choosen to stay with a recir pump setup on my motor builds. I will use the Meziere billet mechnical pump. CAUTION: If you stay with the timing chain, your timing cover will fit OK. BUT, if you chose to use the Jesel belt, the belt pulley has a clearance issue with the pump. I had to use the pump spacers from CV Products. I had them machined for O-ring sealing. Pic shows the pump install before the Jesel belt drive was installed.

I use the cross over set up and run 2 #4 hoses from the water bosses at the back of the intake manifold and dump them overboard. This system works great for me.

I ran circ water pumps on my 600 NA motors with raw water cooling. Still do but have closed loop cooling now. Merc uses circ water pump on their 1200 SCi motor. I guess there is something to keeping block at temp but there are lots of people who run crossovers successfully. I would like to see some knowledgeable members weigh in.

We all boat in relatively warm water during the summer, maybe Merc is looking at more varied water temp conditions with the circ water pump, tstat and the rest of the water system they run.

BTW ran the supplied crossover on my old procharged 502EFI and did fine. No issues.

Meziere, also sell's the spacer's already machined for an O-ring :D Your engine is looking nice!

Jon

Thanks Jon. Yes, Meziere does sell the spacers. But, correct me if I am wrong. The shortest spacer Meziere sells is the .500? CV makes a .375 I believe.

IM currently chasing issues with the crossover on my engine, with the bypass from the crossover to the thermostat housing installed the stat will not open so I went to flow restrictors but the temp will only get to 130. then you need to worry about how much raw water pressure your system is generating. my advice is to stay with the circ pump, the crossover has too many issues compared to the benifits.

I think you may be right, and then .900 is the next size.

Jon