Thread: Newbie has a question

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Hi everyone.....looks like a cool forum, thanks for letting me in. My problem is with a chevy 350 sb, just installed a blazer 294-2h crane cam with matching valve springs. Rocker arm keeps sliding off valve, and head has wear groove in push rod guide. Been brainstorming for three weeks trying to figure out what is going wrong. Help would be much appreciated. Thanks

Stock heads and rockers?
same one keeps coming apart, or more than one or ??
when it is all toghether, does it run OK and for how long till things come unglued? My first thought is that the rockers are not tight - or are missing parts (the little ball type thing) Are the push rods strait? roll them on a pice of house window glass (cause it is flat) to check for bent rods.

By wear in push rod guide of head - do you mean the large-ish hole, intake side, that the push rod passes up through from the lifters to the rockers? The push rods shold not touch anything on the way up at any time.

U could have some real bad valve train geometry goin on lettin the push rod jump out!On further thought if u do its probably what streets said.Will a valve train girdle prevent that?

Wow thanks for the reply guys... to answer your questions, I'm using original 1.5 rockers same pushrods (straight), not always same one that comes off, first time it happened was during cam breakin, and yes the wear is in the head holes for push rods.

I would look at screw in studs and stamped steel guide plates, because that crane cam will have a bit of lift and will / could work those press in studs out. While your at it stick in a set of long slot rockers wind the motor over by hand to with the plugs out and with a straightened paper clip and 1 stick it between the rocker and stud for clearance and 2 between the valve spring coils to check for coil bind as check to insure against catastrophies.

If I remember chebbies correctly, with hi lift cams and stock heads sometimes the pushrod holes in the head have to be enlarged mandating screw in studs and the stamped steel guide plates. If the push rods are hitting the guide holes, it will knock them out of the cup on the rocker arms. As mentioned above, you will probably need the long slot rocker arms also.

JJJ hello,
Welcome to the jungle, I don't have a lot of good to say about the grind on a 292 cam ( too much overlap for me ) but the lift is rather high for stock heads. I have seen a lot of broken springs, and dropped valves from 292's so I am happy to see that you got the right springs for it- this doesn't mean that you don't still have to check for spring bind, as well as seat presure of the spring. It should be 1/8 on your feeler gauge when at full compressed on the head.
Now if you have all of this & it checks out, and it happens again then I agree with streets....the studs are pulling up.
Good Luck, & welcome

This is great input guys, I'm feeling better about my engine...hehe. So I picked up some long slot rockers and thinner spacers for under the prings for extra safety. To put threaded bolts and plates is quit expensive.... I've heard of pinning the stud bolts with roll pins, is that safe or not recomended. Not sure if this has anything to do with my problem but since new cam i have very high oil pressure with stock pump.
Thanks for all your help.

That is what i thought too.... someone told me to get more spring clearance I'd have to put smaller spacers under springs, I wasn't sold on that so i asked you guys. Now I know. The studs you are talking about are better priced compared to 480 bucks for threaded studs!

You gotta quit driving the Jag to the parts store, my friend...Thats WAY outta line for cost. Even if they are pricing the wrong parts ( ie. block studs for heads ) instead of rocker arm studs.
Unless your getting them installed.

That is quite reasonable, the pricing i got did inlcude machineing head lobes, drilling and taping threads, and guide plates. But I hated to spend that much on a hunch. I just ordered those studs... thanks.

Dont dissappear on us now, let us know how you got on.

On what?

your engine repairs

u have sparked curiosity inquiring minds wany to know