Valve dramas with my 302

[Ross Nicol]

Ok in my last post to this forum I described how I got stones down #1 inlet trumpet and after chipping a valve reduced me to 7 cylinders. I removed the heads and took them off to the machine shop.Plan was to replace the chipped valve and reseat all valves in both heads.Then the bombshell came yesterday with a call from Glenn at the machine shop to tell me I had 4 bent exhaust valves and asked had I been having backfiring and idle problems. I initially said no but when I thought about it a bit more realized that yes it has been popping and banging at throttle release coming in to corners and Idle (what idle) and has been like it for some time. I had put the noise down to
lean mixture. Pistons and valves have been kissing due to valve bounce/float.
A higher quality set of springs is going in and power should be back up to scratch. Looking forward to next race meeting at Phillip Island 9th & 10th June

 

[Doug S.]

I've been following this saga since your first post about the stone. You are so lucky--the last time I lost a bit of a valve I ended up with a hole in the block the size of a piston, and the combustion chamber was so beaten up that the head was unusable from then on. You were very fortunate to catch this early!

Good luck--I bet it runs much better when you get it back together.

You are right about the air cleaner issue--they may cost a small amount of power but may save a large amount of $$!

Doug

 

[Ron Earp]

Ross how much do you rev it and what is your valve train like with respect to lifters, springs, and cam profile?

R

 

[Ross Nicol]

Ron
I've got hydraulic lifters and I rev to 6500 with the limiter set to about 6700.
Glenn reckons the standard X303 springs are a bit weak and is fitting a better
set. He says this will fix the valve float. I have a B303 cam with .480 valve lift, nothing extreme, also .6 rocker ratio. It's amazing that I never noticed the performance drop so I think regular dyno tests may be in order. Definately looking forward to the return of performance. Just amazing how well the old FORD 302 goes even when it's a bit sick

Ross