Titanium Valve Runs

We run a blown alcohol 526 Hemi old AJ stage 2 fuel heads in a Two wheel drive pulling truck turning it 7500 to 8500 rpm average. Whats the life of the valves? How many runs before installing new ones? Never leaned out the motor or have to adjust the valves and always checks out good with about 60 to 70 runs on them.

 

Need engine builder input on the exact measurement - but replace when the margin is too thin....
I also look for any movement in the lock to the valve stem (we use radial groove locks) - if there is any slop in the lock to valve stem then pitch the valve...

 

Depends on rpm and seat psi. I change mine at 70 runs with my hemi. 10,000 rpm and 540 lbs on seat . You can also measure against a new one of same manufacture.

 

Thanks for the info

 

70 runs seems like the go to number in a drag car if you take care of your stuff. If you have a tuneup issue and the head of the valve looks like it may be sinking, by all means chuck that sucker in the trash, it’ll save you lots of money in the long run. It’s a good idea to measure the valves before you stick them in and check them periodically.

Keep an eye or your retainers and keepers, I have heard of some top teams having retainer failure issues and some have started changing retainers every other set of rods, which when you think about it, really it’s cheap insurance. Both instances that I know of broke the retainers in the 50-70 range.

I personally would never straighten a titanium valve either. I know there are guys out there who do, but for the cost of a new valve it’s a good piece of mind vs dropping a valve and head / block repair. Good luck!

 

No one mention flaking of the coating in the stem/head transition area.

We had two valves with 40 runs do that and that is a no go for me. Any marks, scratchs, lock area problem we discard them.

An old timer once told me "the only expensive valve is a broken valve" I keep repeating that to myself over and over when servicing heads

 

We replace our retainers when the installed height is .005" higher compared to a new retainer....meaning there is wear or spreading in the lock area...