big block valve problems

[bajabob]

had this motor built 2 times the vale bent 2 time broke the vale. has one spring on the vale !should it have 2 or 3 springs ?? myold motor had 2 springs . this is a marine motor


4340 Forged Steel

10.0:1 Forged Pistons
Moly
Race Series
Race Series
ARP
Balance customers Flywheel to Internal
Internal Balancer



Marine Yellow Chromite 345cc Heads
Full Roller Customer Supplied

ARP Complete Set


Race Series
Retro Roller Kit
Double Row Billet / Torrington Bearing
Pro 3/8
Roller 242IN 254 EX / 566IN 575EX


High Volume
Pick up Screen
Performance Shaft Steel Coupler


Install Kit
Marine
Rear Crank Seal


9 qt
Large Windage Tray
Small Windage Tray
Tray Bolts
Chrome
Poweder Coated and Engrave
Chrome


Customer supplied
Customer supplied
Customer supplied


Pro Billet Marine Dist
Marine Box with Rev Liimit


Assembly
Test and Tune


Block Hone
Dynamically Balanced dyno 600hp at 5800rpm

[want-a-be]

Sounds like you are running a roller cam. If so,..sounds like you're running the wrong springs.
How much piston to valve clearance did this thing have?

Don

[bajabob]

yes it is a comp roller cam i do not no clearance . ihad the motor built

[want-a-be]

I have to say that the single spring being used as a valve spring kinda throws up a red flag. Valve could be slinging over the toe of the cam and hitting the piston due to low spring pressure. JMO though.

Don

[bajabob]

don you are rigth on that there are marks on the pistons now my timing is 36 the boat ran good but top speed was not the same all the time 78 was best then go to 75 to72 .the vale broke at 75.6 at 4900rpm the motor redline is 5800

[Awesome Bill]

this valve was broken becasue lack of installed and open pressure. The spring would be fine with a single if the single was good enough for the application. This is what happens when the valve is lofted off the cam and then slams back into the lobe. Some times it even does it on opening!. Your machinest done you no favors when he set this up. This is under 100 lbs of seat pressure and under 300 open that does this. We use a minimum of 150 on the seat and 400 or better open for camshaft lift used. Titanium, titanium, titanium titanium! Stainless valves are very heavy. You had no piston to valve problems here. That would be silly to think this with a small hyd roller like this. Your other pistons show none of this.

If you want this repaired and set up like we do it on ours, ship them to me. We build a ton of Marine Monster 540-565ci engines with hyd rollers and have never had this happen.

[bajabob]

thanks bill the motor is a one year warrntty . so i dont no wt to do ? i hoping it is fix rigth . thank you for your info .i will have to see wt they did to fix it ??? i will post the fine then take it from there to see if i have to make changes :confused:

[want-a-be]

is this a hyd roller or solid roller?

Don

[Awesome Bill]

I would suggest getting some weight off those heavy intake valves and maybe the retainers. Comp Cams make some Tool Steel retainers that are within 1 gram of Tit and half the cost.

[bajabob]

is this a hyd roller or solid roller?

Don hyd roller comp cam