I have my car at Speed inc and they are assembling my 383/TFS head combo. They said they are having an issue that they have never seen before. They are unable to lash my valvetrain because some of the rockers will not properly line up with the tips of the valves. Some rockers they are able to lash but others will not sit flat on the valve or are barely touching the valve stem tip at all. Here is how they described it via email.

"Please get me # to speak to your engine/head guy. I have an issue we have not seen and want to talk with him. The issue is the rockers…comp or Crower will not roll a flat pattern on the tip of the valve. The roller is more on it’s side and maybe contacting 40%. There are few good and others that are not good.We had our machine shop guy look I over and suggested valve guides or rockers stud holes are not all true… this is a very uncommon issue.
I do not know what to do at this point."

He did also say he tried different guide plates also. Do you have any idea what could be causing this with TFS heads? They were fully ported by Lloyd and I am going to be pissed if they are junk casting. The block was built by CMS. 383 with custom cam by Lloyd. Could it be a problem with the block?
Thanks in advance,
Randy

 

Nope not a problem with the block. It sounds like they are describing a rocker roller tip that is not parallel to the valve tip. There are a couple of possible causes -

1. The guide bores were mis-drilled at the factory and the valves are now canted
2. Same situation with the rocker stud holes and pad, it was mismachined and now the rocker is being canted at an angle not matching the valves.

Those would assume some problem in the machining process, which is all computer controlled, if the setup was bad, all the rockers would not line up correctly, so the above two are possible but doubtfull

3. couple of the rocker arms are messed up, either the trunions are mis-drilled or the body is tweaked

I would think that with only a couple effected, that it is a rocker issue or something else that doesnt come to mind right now.....

 

It cant be a probelm with the block. It has to be with the head or rockers.... I would think you could check the head fairly easily with a set of calipers by measuring the distance between the top and bottom of the rocker studs between cylinders and comparing numbers.

But as already stated I would highly doubt there is a problem with the head since they are all drilled with precision machines.

Rockers could be a problem but if the roller was not sitting perfectly parralel to the rocker body I would think they would bind. Easy way to test is to swap a rocker that is sitting properly and one thats not. If the problem stays with the rocker your have a rocker problem. If the problem stays with the cyl you have a head/valve problem.

Another place to check is the valve itself. The valve stem could be bad if they are used valves or they were cut worng if they are new. Again swaping valved to a different cyl should proove this but not easy to do since you already have the heads on the engine...

I'd look at swaping rockers around and measuring the rocker studs/ valve stem distances first.

 

I know your situation stinks, but at least Speed informed you of the problem and is looking out for your best interest. Some of the other shops out there wouldn't have found the problem and or bothered to fix it. Good luck with your project.

 

My only addition is that your builder should have figured out the problem and then contacted you, made the measurements himself and then inform the customer what needs to be done to correct it, never contact a customer with a "something is wrong and we dont know why"

 

I was thinking the same thing actually...

If my engine builder told me he had no clue why something was wrong I would be out looking for a new builder.

 

I noticed the problem when trying to determine proper pushrod length.

The rocker tip is not parallel to the valve, and that means either the guides or rocker pads, or rocker arms were machined incorrectly. (as machinistone explained).


This is the case on every valve, some more pronounced than others. I tried both Crower and Comp rockers with the same results.

Since Randy supplied us with both the shortblock and cylinder heads, I suggested to Tom and Larry that they find out if the person who did the cylinder heads would correct the situation or if it was something our machinist would need to look at.

It's not a case of we're incapable of correcting the problem, but it would be at an extra cost to Randy for us to disassemble the cylinder heads to find and correct the problem. Instead of taking that route I suggested we contact the person who did the cylinder head work, as we did not sell him the heads, machine them, or assemble them. If they are new castings and original guides than I believe TFS would be responsible for correcting the situation. If the guides have been replaced, than maybe not, but I do not know the history behind these particular heads.

 

Got the whole story now. Really crappy part of that situation is that nobody would catch it before the step that you were doing, unless you are looking at that as a common thing from TFS, in which case I would not use their castings anymore. It's not like TFS is going to pay for your porting on a new set....so the next step is to find out whether it is the guides that are canted or if it is the rocker pads and studs.

 

This is the response from my head guy. AKA Lloyd Elliot.
I would like to make it very clear to everyone here that SPEED Inc is not responsible for the assembly of my heads or block machine work. They were just doing the basic engine assembly and noticed the problem. Here is what Lloyd has to say. He seems pretty certain this is the issue.
I would buy some TFS guide plates and see what that looks like.

Things will look "goofy" until these are installed.

As mentioned, I can't see two heads being off" from TFS and you just
happened to get the 2 bad ones. The pushrods probably can not travel the
path they like and are hitting the pushrod tubes making it look even worse.

$25 TFS guie plates from Summit will do a worls of good. Once you see them,
you will see the intake PR is offset from the stud. I do not even know if
the studs are in the stock location, they might be positioned in different
place than others. The stud will need to be in like from the valve stem and
the new pushrod location. I would not start worrying until you get these
guide plates and then things do not look right.

More people would have noticed something as severe as they are claiming and
your heads were bought a whole back so "if" this was a common problem, more
would have posted up or a recall would have even happened as replacing a few
heads would be cheeper than buying engines from law suites doe to idiots
just running them with rockers half way on valves and destryiong
parts/engines.

Lloyd Elliott
972-617-5671
Eportworks.com

 

Jim,
Lloyd was very adament about the TFS guideplates being the only ones that would work on the TFS heads. He told me he tried almost every other kind and only the TFS guideplates provided the right geometry for the heads. Please give these a try. If the problem is with the casting TFS has to be made aware of this issue. I did have some of the first castings out there. If your machinist has to remedy the situation that is fine. I have way to much money in this combo to not fix it. If TFS is at fault with the castings then they should be responsible for the tear down/gaskets/porting that went into these castings. I do understand that there was no way to see the issue in advance. What I do not understand is why the 2 cylinders I tested produced a clean sweep across the center of the valve. This is odd. I did try comp plates at first and it was clear as day they would not work. Then I tried the GMPP plates and they looked MUCH better. Maybe the TFS ones will remedy the entire issue.
I am sure if Lloyd sees this he will chime in his thoughts.

 

Yep, the TFS plates are what you should be using or Isky Adjustables. I run those on about EVERY set of anything that I do anymore since the Iskys let you get everything correct. Isky PN AGP-200

Bret

 

Thanks for the advice Bret. Its one of your cams in there!

 

Well we can certainly try a set of TFS guideplates. I wasn't assembling the engine so I was unaware that the guideplates were not matching pieces, though I fail to see how guideplates will correct this problem as the rollers are laterally aligned to the valve, but not parallel to the valve.

 

Yeah - That would be my opinion too. Rockers fit pretty tight over the stud, and that determines their ability to be parallel with the valve.

 

Get us a picture of them.... have you tried setting them up without plates at all to see if that helps?

Bret