I am going to install LT4 springs,1.6 LT4 rockres and new lifters in my motor the question that I have is do the springs have to be shimmed a certin way or can I just install them with one shim plate and be done with it or do they need to be shimmed a certine way? Also I was planning on doing the rotate to TDC and drop the valve method, this wont bend the valves will it? Any help is appreciated, thanks!

Brian

 

I asked this same question a while ago, and the only responses I got were, "you're going to need a barrel mic to set the springs up the correct way." Nobody elaborated on this, so I don't know what the barrel mic is used for, I just know I need one. My suggestion is to look for a book or procedure for head rebuilding. I just never got around to it. I'm switching to LS-1 car, instead. Good luck.

 

Based on the lack of responses, I feel pretty sure that a lot of people just throw springs in and never look back. Apparently, it works for the most part. You should actually measure each one with a valve spring height micrometer or another type of mic. Most people don't have these tools and don't want to buy them.

Here is a write-up from Comp Cam's site:L
http://compcams.com/information/Products/ValveSprings/

I have purchased a spring height mic for my upcoming cam and spring install. It is probably going to be a bit of a pain to do it while the heads are on the car, but I am going to give it a try. It will be my first time doing this myself.

 

Thanks, Shoe.

 

::raises hand::

Another "just threw them on" person right here.

Ryan

 

i just threw them on... no problems. also why are you going thru all this and not going on a step further and getting a cam??

 

I did the TDC procedure and it worked fine. Pull out the easy sparkplugs to make rotating the engine easier. No special mic tool required unless your blueprinting your engine. Nothing like that is done at the factory, it would be too labor/time intensive so you don't have to woork about that. You will need an "on the head" valve spring compressor though. You can usually rent them from your local parts store.

 

I agree that the factory may not have been doing exacting measurements, but everything they were putting on was the same in every case. It is a little bit different when changing to something aftermarket and the engine is not coming off the factory floor. More variables, more reason to take steps to be sure. At least that is the way I see it.

I am going to take a little time and maybe spend an extra dollar or two, to do what I can to be sure things are what they are supposed to be.

 

If the installed height of the spring is tall, the correct pressure won't be applied to a seated valve, possible leakage. It will also affect how fast the valve closes when it's coming of a lobe.

 

Thanks for the responses guys. Turbo Z, this is my daily driver and I can't afford too mutch down time even though I would love to put in a cam! The motor has 71000 miles on it and from all of the bad things that I have heard about the stock springs I just decided to up grade them. Plus I am replacing lifters and I figured it looked simple enough so I would replace them while I have the rest of the motor apart.

 

I just through mine in and haven't had any problems...

Aaron

PS..this was with the hotcam also.