468 w/871 blower
 

I keep tuliping valves in this motor combo, I realize that the blower builds heat and running it for an extended time can be part of my problem..however my water pressure is extremely low all the time, at idle or at speed , but the boat temp never goes above 150..Can boat run that cool on 4 psi or is the water pressure gauge wrong??

Re: 468 w/871 blower
 

4psi is low. Yes it could but check your gauges to be sure.

Tuliped valve is from running lean usually. HEAT is the cause.
1. What manufacture valves are you running? Type and material?
2. What type of valve job are you running. Single angle with a wide seat for cooling the valve. No exotic 3 angle valve grind I hope.
3. How much boost and are you inner cooled?

Sorry for your trouble but blowers can be dependable if not set on KILL. A lot of good resources here just hang on and it will come.

Welcome to the board!!!

Re: 468 w/871 blower
 

3 angle valve job yes---intercooled yes--9 psi boost--manley encanel

Re: 468 w/871 blower
 

Manley valves should be OK. I can not stress a wide single angle seat to help cool the valves though.

You really need more water pressure. Steam pockets are not good but usually you will have detonation problems. Where are you checking pressure from and are you running no thermostat - with a cross over?

Ignition timing retarded will cause exhaust temps to run high. Are you carburetors?

If you do not run pyrometer gauges you might want to even if just for set up.

Which cylinders or all of them. Just throwing some ideas out to look at.

Re: 468 w/871 blower
 

no thermo w/crossover yes--the motor is apart as we speak and the heads are on there way to the machine shop so I can fix the angle job this time, thanks for the heads up....It started with the back cylinders, but it worked on almost all of them...explain pyrometer gauges??? I am unfamiliar...THANKS

Re: 468 w/871 blower
 

Carburetors Yes--

Re: 468 w/871 blower
 

Pyrometers measure the temp of the exhaust gas. It will tell you when you are getting to hot and warn you before you melt a piston or tulip a valve.

Re: 468 w/871 blower
 

"Problems starting with the back cylinders first"...sounds like a clue that water flow was weak there, forming steam pockets. I have also heard people say that your style of blower pushes fuel to the front cylinders. Whipple taps into their intake manifolds at the back to take some of the water out of the block there (for these reasons?) 9 Psi is lots of boost, have you also confirmed good water flow through the intercooler?