If the entire row of rockers moved up and that was the problem; it seems to me that ALL of the rockers would impact ALL of the retainers. Since only one retainer has the scratch marks, I bet you have a rocker on the way out. Or, less likely, one spring that was not installed at the correct height/pre-load.

 

The guide moved up on a angle. All of rockers were not aligned correctly.
We disassembled and reinstalled with the correct procedure and torque specs and we will see what happens.

 

That is why i posted.
Someone made a reference "you need to talk to your pro".
I racked my brain trying to think of cause and needed some assistance.
We checked the wipe and all rocker tolerances and everything is fine.
Rockers are not worn out.
Thank you to all who replied
Regards
B

 

Maybe I misunderstood your thread. It seemed to me you were quick to throw down at Dart but unwilling to look else where.

BTW even "pros" make mistakes. Don't be so quick to get offended unless your the pro.

 

The post was to information rather than blame any manufacturer or vendor. The heads are new to market and wanted everyone to be aware of a issue.
It could be install or set up related who knows. I tried to get assistance from Dart they never called to date. Talked to the head porter and he was at a loss on how something like this happened. We re installed the rocker inspecting the valve train no issues were found. We were even able to understand the movement.
But without hard evidence you cannot point you finger at any given part.
So we did the best thing, set up everything again with the correct procedure and we will see if it happens again.
I drive my car daily so it will not be hard to detect when and if it happens again.

Thanks for all who posted.
Regards
B

 

Not to hi jack. What is the "correct prcedure" that you are talking about? I have a set of Darts and I want to be sure to install the rockers correctly. Thanks

 

The Darts should bolt on like the stock heads, therefore the procedure from the service manual should work fine. It calls for tightening certain rockers with the #1 piston at TDC, rotating the crankshaft 360* and tightening the rest of them. I can't remember the specific rockers that are tightened on each pass, but the service manual spells that all out.

 

Ill try and get the procedure posted?

 

Thanx

 

I dont know if dart is selling these bare without machine work as in the wholes not drilled for the rockers but I have seen personally on sbc heads If I bought a set directly from dart 230cc cnc'd by them all valvetrain would bolt up and have room to adjust with the guide plates. BUT when I bought two different sets that were bought from outside machine shops that built and machines the heads both sets needed alot of mods to get everything right. Also going to swap meets that have auctions held ive seen blocks heads etc, that were blems from dart being sold and when these guys were buying them they all had intentions of reselling so I think dart has a good quality control with someone looking over each piece. those heads are being seen on more and more cars dailly without these issues I would look else where for your problem.

 

They are sold bare but all holes are drilled and tapped.
They are not blems!!!!
Yes they are showing up on cars.
The heads were bought directly from dart.
Ported and assembled by a forum vendor.
Do you have a set of these exact heads?
We were looking at other parts as you can see in my posts.
Most sets that dart sent to shops on a prototype basis we never bolted on cars.
They didn't even know about the rocker guide issue till they were in full production and shipping.

 

I am still not clear specifically on what you found. Were the rockers loose?

Did you do the original installation? Do you know how the rockers were tightened down, more specifically were they tightened when the lifter was on the base circle. Inaccurate torque readings will be obtained if they are not and I am wondering if this might be the source of the problem you encountered.

Guess I am still puzzled by this, since I still don't think the tabs on the rocker stands are the cause of the issue you had. The Lingenfelter rocker stands, which are high strength steel, do not have the tabs and they have never had any problems with them shifting on the head.

 

PM me the forum vendor, I purchased a set too, and just want to see if it's the same vendor.

 

I didnt bother reading through the rest of the thread but this right here says it all. The plate that aligns the rockers keeps the rockers straight on teh top of the valve stem and the only way it could affect the contact of the tip of the rocker and the valve stem is if the bar got twisted. To me it looks like a loose rocker problem. I did the same thing as you on the alignment bar I have 2K miles on my heads with no alignment issues. Its something you did IMO double check everything use loc tite and tq to 22 ft-lbs again.

 

The rockers were not loose. I had a shop do the install.

 

VN
Are you sure this is the correct procedure for stock rockers. LS1 how has;

Insert all 16 pushrods (7.400" is probably needed unless you have highly milled heads or a small cam, in which 7.350" might be needed), place pedestal back on the head, apply locktite to all the rocker center bolts and reinstall all the rockers. Torque the rockers to 22lbft.
Now, using your 24mm socket wrench, turn the motor over by hand (should be difficult as you are now building compression) and make sure the motor turns over by hand a full 720 degrees, then turn it another 360 (doesnt have to be exact or anything).

Go over all the rockers again with your wrench just to make sure they are all at 22-24'ish lbft.

I torqued all of mine at the same time.

 

This rocker guide issue you spoke of like they have admited to you that this is their problem, I was only suggesting to you that it is probably not their mistake. If you dont want advise then dont ask for it and if your not the forum vendor dont take it so personally. I didnt mean to offend you but I think if you bought a set of heads completely assembled by them you wouldnt be in this situation right now.

 

Smart *** dude was on vacation, I dont **** up threads I tell people the answers to their questions. It is smart asses like you though that have kept me off of these boards, I dont have time to waste arguing with some dickwad about this and that. Dont want my answers dont want our help fine, those that do however have gladly emailed and private messaged me.. Now to not waste anymore of my time dealing with your ignorance i will post in regards to this problem.

 

The "pros" know but Dart who has been building heads for 25 years, and Dick Maskin who runs this place and owns it was furnace brazing heads together for Pro Stock racing back in the 70's doesnt? Thats exactly why I have stayed off this board as of late, you try to give FREE advice and people jump all over you. I am sure NOT MEE that I was the one they wanted you to talk to, I was on a much needed and first in 9 years vacation. I just returned today. I agree with Kurt at Wheel to Wheel the tabs you need to grind off are not there to keep the rocker bridge from moving it is a locater from GM for plant assembly, end of story, Kurt if people are not familiar does extensive work for GM development, if he said this it is true. He also has been using the Dart heads in their shop and on their crate engines, without any problems. If the tabs were required than aftermarket shafts would also have them and they do not. Assembled to Dart specs? How is that the case, they are not even the same parts we use?? I think it is funny that everyone is so quick to always blame something without finding out the information. Dont bash companies, that is why companies like Dart and several others I have spoke to recently dont and wont particpate on these boards, then you guys cant get good help from people at the companies who make these parts.. Watch how you ask questions choose your wording better and maybe you will get better answers.

John
Dart

 

Welcome to the internet John Dont get too bitter about it, after a while you will get used to it if you stick around..

I'll just say I am very happy with my heads, car runs OK with them too and its not smoking nor are the rocker arms falling off.. I didnt even follow any 'procedure' for tightening the rockers, torqued them down, spun the motor over and checked them all again - just like I have done 500 times before.