Rather than continue with my other thread re my "second" BIG engine problem, I just want to fill you in on the latest (this is not confirmed yet, but just the same)...

At first glance, my shortblock may be OK, even after the swallowed valve.

The one head was removed and delivered to a machinist by my "new" mechanic. Heresay has it that the machinist just laughed when he saw what had been done to the head (it was supposed to have had extensive porting and fitment with bigger valves) apparently the machinist believes I got screwed. So the first lesson here is "don't take it as gospel that the people who do your heads are telling you the truth."

The second thing I got so far out of this is: just because the RRs you buy are supposedly self aligning, that it might not be a bad idea to go with guide plates and hardened pushrods. The only reason I say this is because both banks experienced a RR coming off the valve stem: the one on the drivers side just beat up the RR a bit. The one on the Pass side really got beat up as the keepers came off and the valve dropped into the cylinder.

Don't know what happened for sure, but it looks like I am going to have my heads done "again" and I will be getting guide plates along with springs that for sure will be strong enough for my baby cam (210/224) BTW, my mechanic doesn't believe that I have that cam in there because of his initial measurements at the valves (don't know how that works). I did, however assure him that I did have that cam and delivered it personally to the mechanic.

In the end, I might just be full of it, but I just wanted to keep you on top of what is happening to me so that you might avoid the same problem. BTW, the "new" mechanic said that I probably have 30+ hp laying on the table just because those who are supposed to be doing what they are paid to do; asked to do: and are supposedly experts at doing, are not...JMHO

 

Only way a SA RR would come off is if it isn't lashed right or something else in the valvetrain let go.

 

On the rockers, you use NSA with guideplates or SA without guideplates. Don't use SA with guideplates.

 

I've heard that LT1 or maybe L98 corvettes came originally equiped with guide plates, and both of these engines had sa rockers.

 

Be careful of what you "hear". I have never seen this.

 

Sucks to hear man, but on a side not, but just because you gave the cam to the builder, doesn't mean that's the cam that went into your engine.

Good luck with it and keep us posted!

 

I've also found it's not uncommon for one mechanic to bad mouth the previous one, so take it with a grain of salt. Definitely pays to shop around and get references beforehand. Good luck getting it fixed...

 

Ok, but why can't you use guide plates with SA RRs? Seems to me that it would not present a problem. As a matter of fact, when I ordered the SA RRs from Crower back in 97, the catalog specified that "if runnning in excess of 5500 on a V8 Dodge Magnum ." So if they will work with the Magnum, why wouldn;t they work with the LT1? Just asking.

As far as "'badmouthing" other mechanics, I am sure that it goes on, however, when you have TWO brand new engines go to hell after a particular shop works on them..."if it looks like a duck...

As an non-mechanic, I would say that using guide plates along with SA RRs would only serve to enhance the ability of the valve train to do its job in an efficient and stable manner. I am going to give Crower a call this am and see what they have to say.

The whole game of modding can be a crap shoot, especially if you are not doing your own work or if you are a DIY person, but not an expert mechanic.

So you are really at the mercy of others, most of the time. JMHO

 

Reason being the SA rockers have small lips or keepers on the end of the rocker tip that is supposed to keep it from sliding off the valve. And a common problem with the NSA rockers on LT1s is that, even with the GM LT1 guide plates, the tip of the rocker is not always centered perfectly on the top of the valve... anything but the GM LT1 specific guide plates and the problem is really exaggerated! So if you were to use guide plates, that puts stress on those keepers which could cause any number of problems from metal shavings in your motor to the rocker falling off the valve.

 

OK, but just got off the phone with Mr. Crower. He said that he advises that I have guide plates even with the SA RRs since they already came off once and dropping a valve because of whatever reason: weak springs, over reving, etc., putting guide plates on only makes sense.

So even if your logic is sound, I find myself yet in another situation where some say yes and some say no. That is exactly my point.

 

The 2 methods of rocker alignment are at different ends of the rocker arm movement.

Guideplates corrects the alignment before the action even gets to the rocker arm.
[edit]SA (not NSA-sorry) rockers do the aligning at the very last place it can be done-at the valve tip.

IMO, you don't want one trying to override the other. If the guideplate skews what the tips on the rocker are trying to do (or vice-versa), then there is going to be some unwanted action. One method of alignment is enough.

With your luck, I don't know if I would push the matter.

 

Shoe: Don't you mean that the SAs align at the very last, and not the NSAs?

I'm confused enough.

 

I'm also kinda confused on why you can't use guide plates with SA rockers. Seems like to me it would only give extra assurance that the rockers won't come off the valve. The guide plates keep the pushrods straight, correct? The SA rockers have the extra lip on the roller tip to keep them on the valve. I don't see how one would interfere with the other because on a SA rocker setup the pushrods should already be straight but in case the roller tip gave way it would only keep it there anyways instead of falling off. Maybe those that believe the guide plates would get in the way could explain why.

 

I had the same sort of problem...a sa rocker slipped off of the tip and it only knocked out 1 keeper...thank you, But all of this was just a result of not having my rocker tight enough. Make sure you get those polylocks good and tight so that the rockers dont fall off.

 

Exactly. Up til now we've been talking and talking about how important it is to have the correct lash, etc., but mostly we talked about its importance to get the most power, quietness, etc. It is not til now, that I recall, that we talked about how a loose RR, esp. a SA RR could come off the valve stem, take the keepers with it and allow the valve to drop into the cylinder (with the real possiblility of ruining the engine.

Well, I experienced just that. I won't know til sometime today whether I will need yet another shortblock rebuild. And probably because of the bad combination of too weak a spring; too high a rev; too loose a RR, etc.

Since I don't know which of those (perhaps all three or more) caused the problem, I plan on having the Guide plates $35.00 worth installed if my mechanic and Mr. Crower advises same. I don't want to take the chance that the RR will go to hell again. Or next time I'll just have to push the sucker into the river and flee to Mexico.