C_Spray

iTrader: (2)

I'm considering upgrading my Innovation 600's this winter, including new valvetrain and AFR heads. That being said, I'd be looking to sell the used take-out parts. My question is how hours affect the life of these components versus the RPM they are used at. When Volvo Penta commissioned these engines from Innovation, the goal was for an engine life of around 700 hours between major overhauls. Innovation tells me that they have a set in the field with over 700 hours, and I have heard of almost no failures with these engines. At the moment, the engines run flawlessly and sound great, but I'm just getting a little nervous about the hours on them.

I've got 570 hours on two sets of these components:

1. GM BowTie iron heads with Innovation porting and bowl blending
2. Morel hydraulic roller lifters
3. Crane gold 1.7 aluminum rockers
4. Pushrods (unknown spec)

And 200 hours on Isky 8005-SP valve springs and seals. (When I replaced the originals at 350 hours, non of them were broken.) The heads were off to replace the springs, at which time all the seats were touched up. Only 3 out of the 32 required a very light cut; the other 29 lapped right back into spec. The photos below are from when I pulled the heads at 350 hours. I would provide current hot and cold leakdown and compression numbers for everything.

These engines have never seen over 5200 rpm, 99% of my cruising has been between 3700-4000 rpm, and 25% of the hours are at idle speed.

Given that history, are these components at risk of failure, and is there any market value for them?

Budman II

iTrader: (1)

I would think that the profile of the cam would play into this, especially in regards to gross lift and how aggressive the lift rates are on the cam. Some grinds concentrate on really getting the valve off of its seat in a hurry and keeping it open as long as possible, and some are set up to be gentler on valvetrain components. From the comments that you made in regards to Innovation setting these engines up for the long haul, I would think the latter scenario, but it would be good to know.

It all comes down to your personal comfort level. Think risk / reward. How much money are you saving by waiting until the 700 hour mark, versus the potential disastrous consequences of a valvetrain failure. Unfortunately, there is not any easy way to tell if metal fatigue is starting to set in with these parts until something happens.

As far as market value, I'm sure someone out there would buy them for the right price. I wouldn't run 500+ hour valvetrain components on my boat motor, but there are people out there who would. Maybe a weekend hobbyist drag racer would want to take a chance on them, or someone slapping together a motor for a boat they are getting ready to sell (although I wouldn't advocate that).

C_Spray

iTrader: (2)

Cam is essentially a 741, about .690" lift.

In some ways, I would think that the stressed induced on the moving parts at 3800 would be about half of what they would be at 5200. At the same time, stress cycles are stress cycles...

I can see the value of the lifters, pushrods, rockers, springs and valves being a crapshoot, but I would hope that the bare heads alone would be worth at least $800 a pair.

blue thunder

The lower the rpm the cooler the valve train runs. More seat time for the valves to cool. Heat is what takes life away. So you're 3800 vs 5200rpm would show a lot less wear. That being said, 3800 is not running easy in my book, 31-3200 would be.

Budman II

iTrader: (1)

I agree with what Blue Thunder said - 3800 is leaning on it a bit in my book. Far from an easy cruise. I like to cruise right at about 3200 just before the secondaries start to open.

Bob Madara told me that a lot of guys don't realize that running at 3800 - 4200 RPM for long periods of time puts a lot of stress on valvetrain components - especially exhaust valves. They get HOT! Which is why he thinks even non - supercharged performance applications should be running them.

The 741 Cam is pretty stout. That is a lot of lift to be cycling those springs and other components for 500+ hours.

I see no reason to replace the heads themselves. Just the components.

C_Spray

iTrader: (2)

Correction - valve lift is more like .610"/.632", not .690...

Considering AFR 305 partial CNC or 315 full CNC heads for a quick hp gain (50 or so?) and to take a bunch of weight out.