I need to know if I am going to have piston/valve clearance issues. I have the TR 230/224 cam. The lift is under .575 I think. The heads that I bought are 5.3 litre trucks from TEA. They have been milled .10. Will I have problems at all? Does anyone know what my compression is going to be?
Thanks, Kaley

 

The "Key" is your LSA. If it's pretty wide 114-116 and you were using LS1/LS6 heads you would probably be Okay. I'm not sure with the 5.3 heads. You should ALWAYS check them to be sure. Post on LS1Tech.com or do a search in their "internal Engine" section. Alot of Guys running TEA 5.3 heads over there. :yesnod: Let us know what you find out. :yesnod:

 

You should be fine, but as they say, its always better to check it now than to find out later. There is an easier way to check it using the "valve drop" method and a few measuring tools instead of messing with clay, solid lifters and a light valve spring.

Here is what I did with my G5X2 Cam and Absolute Speed 5.3L Stage-2 Heads:
LGM told me that the intake valve lift is .120" when the piston is at TDC. You want a minimum of .080" PTV clearance. So take the valve lift @ TDC (.120") + the min. PTV clearance (.080") and this is the min. amount the valve must drop before contacting the piston (.200").

#1 You need to find out from TR what the intake valve lift is when the piston is at TDC.
#2 Remove the valve spring from the #1 cylinder on your head.
#3 Using an indicator, rotate the crank to place the #1 cylinder to TDC.
#4 Install the head (using an old gasket) and tighten it down (no need to torque it).
#5 Lift up on the #1 intake valve and while holding it up, measure the distance from the tip of the valve stem to the spring seat and record this dimension.
#6 Let the valve drop down until it hits the piston and measure the distance again and record this dimension.

Now for the calculation: (Example)
In my case (using the #'s above) I needed a minimum of .200" valve drop.
Distance from the valve tip to the spring seat with the valve up = 1.850"
Distance from the valve tip to the spring seat with the valve down = 1.650"
Subtracting the 2 dimensions you have exactly .200" of drop and you're fine.

Actually in my case I had only .150" of drop and had to fly-cut my pistons .050" to use my G5X2 cam. I hope this makes sense.

Also, with .010" milled off of a 5.3L head you are pretty close to 11:1 compression depending on how much chamber work they did.


[Modified by MTWallet, 11:41 PM 8/5/2003]

 

I have seen 5.3 heads milled .o35 with a 230 .575 110lsa and not have P/N clearance issues

 

TTT

 

Just to give you some reference - I'm running 5.3 heads milled .030" with an MMS 229/229/112 LSA with .578/.578 lift. CR is 11.3:1

:yesnod:



[Modified by Patches, 2:10 PM 8/6/2003]