Dropping Valves

I always use BAE Ti retainers and keepers. I don't know who makes them for BAE. I have heard that it is Trick Titanium. They never seem to fail. I still check them on a routine basis. Also double check that you are using the correct keepers for the groove shape in the top of the valve and that the keeper is the correct degree angle for the retainer.

If you drop an intake valve in the run then the supercharger may get airborne.

 

Urban legend. Most Ti comes from Russia. We do get some from Canada and some from Georgia. There are other places but they are just small amounts.

 

Good point Richard. If the springs are going into coil bind it can pop the keepers in the retainer and cause the retainer to break.

 

parts

If you're only running 350 lbs of seat pressure, that may be your problem. You also might be running into coil bind.

400 lbs should be a bare minimum for just about any blown/boost application. 425-450 is better. It is very hard for the intake valve spring because it is closing against boost. It also has pressure against the backside of the valve when closed, effectively lowering your actual seat pressure. I don't know the formula, but if you figured it up, with 350 lbs at the seat, your effective seat pressure with boost is probably 250 or less.

If it is tuliping the valve, you may want to double check and make sure you have the right valve for the application. I've seen valves that weren't beefy enough tulip.

We are talking about Ti valves, right?

Most of the big CID stuff isn't really designed to work in boost applications.

Hope that helps.

If you want to talk to some experts, here are the numbers to some of the smartest people in the biz:

Noel Manton Manton Engineering: 951-415-7348
Ken Jusczcyk PAC Springs 216-390-4561

 

When you are saying 400 lbs plus of spring pressures then I don't think you are talking about BBC or Ford BB motors. You may require that on a Chrysler hemi because of the valve geometry but not on all motors.

 

valve

Not to come off as a smart ass reply, but how does the valve know what engine it's in? I wouldn't think it's going to have much smaller than a 2.400 intake valve? Even with a smaller valve, sure you reduce weight and you reduce surface area, but more pressure is going to control the valve better in a boost situation almost every time. 425-450 lbs should be well within the operating range of any rocker gear. I can almost guarantee you'll pick up more hp controlling the valve better than what marginal losses you'll run into with increased spring pressure.

Pressure is just one theory. Sounds like the springs could be too close to bind as well, which will cause all kinds of problems. Too close to bind and not enough pressure could be at play here. In my opinion, if spring pressure isn't the problem, it could be a problem for sure.

You mentioned the heads were assembled, did you disassemble them and check pressure on a bench unit like a rimac? Sometimes on the head testers can be off +/- 100 lbs.

Just do your homework and see what's different with your combination than other turbo cars.

 

I believe it has to do with valve train geometry. There is no way we run 400+ lbs of spring pressure on a BBF and I have never heard of it being required on a BBC. Some guys may do it because it is done on the Chrysler hemi so they think it needs to be done on theirs. It probably doesn't hurt to do it but not required. Also I don't think Billy (Promod83) is going over 10,000 rpm probably not even 9000 rpm if that. Since the heads were set up by Sonny's I would assume that they know what they are doing with spring pressures.

 

geometry

Maybe its because I'm not an engineer, but I don't know how geometry is going to make the valve close better against boost? Most of the work is changing direction, then closing the valve against the pressure in the runner and moving the weight of the valvetrain. Sure a rigid, properly aligned valve train should be somewhat easier to close, but I can't see it being a major factor on a boost motor.

Again, it's my belief on a boosted motor you'll gain more HP by controlling the valvetrain than residual losses due to spring pressure. I think geometry helps more in controlling the valvetrain, and making your valvetrain do what your cam is trying to tell it to do more accurately. You still have to close that valve effectively and control it.

Higher seat pressures and springs with high open pressures like Ti Springs, the PAC 1320 dual, the new Manley duals, etc., are relatively new in the grand scheme of things. I've ran into a number of guys in Europe with hemi's that still run spring pressures in the 300's on a Top Alcohol car.

I may have just shown my ignorance in valvetrain...like I said, I'm no engineer, just a practical application specialist...

OH, and Mike 8973's suck