YotaBoy83

Hey so I have the block from an 83 that I will be rebuilding here in a month or two and just trying to research everything and start buying parts so I know what to do. My question is should I deck the block and what are the reasons for doing this? Also what things will I run in to if I do this? I will be putting a 20r head on it. The only other head I have is from a 86 22r that would need a rebuild. Any and all input would be great. Thanks

93yota22re

I'm not an expert like some of the guys on here but I don't think decking the block should cause any problems. It is done to ensure the mating surface between the block and the head are perfectly flat so you get a good seal out of the head gasket. Are you planning on borring out the block at all? The only issue I could see is a change in compression from decking the block but this really shouldn't matter and should be very slight and not at all if you are going with oversized cylinders as well. If your sending the block to the machine shop for any reason I would have it decked. At least slightly to resurface

igotit

decking more than 0.12 ths will alter your timming,an adjustable cam gear may be needed.
decking is done for a few reasons.
pitting on sealing surface that would cause a poor seal.
slightly more compression.
warped head/block.

i decked my 22r 0.10 for pitting.remember to take the same amount from the timing cover.

YotaBoy83

so if the block is decked only .10 I should be fine with all my timing and things like that. Is this safe to do when running a 20r head or should I run a thicker head gasket?

YotaBoy83

And yes it will be bored out about not sure how much though i'm still running the motor in my truck. I'm rebuilding it in the spring due to extremely low power.

igotit

not sure on the 20r head swap and decking.

YotaBoy83

Yeah that was my concern I was thinking if I get it decked then run a thicker head gasket like one I saw on lc engineering I would think that I would be fine with timing and compression. This is the only thing I was unsure of. I know I am boring it out getting the rods honed, possibly a new cam and leaving the head alone other than a port and polish and cleaning since it was rebuilt a few thousand miles ago by previous owner.

peow130

You can deck the block, you just need to make sure you deck the tchain cover as well.
If you go over a certain amount, you'll need to look into a copper gasket shim between the head and block and gasket. I know my pickup had one, i tossed it because it got mutilated the first time i tried to re-do my tchain guides.

xxxtreme22r

Mine was decked 10 thous. I can feel the cam timing is off based on my rpm power band. I need to put the adj. cam gear in mine. I didn't use the thicker head gasket, because I wanted to gain back some of the compression I lost by boring it 20 over.

And x2, timing cover must be taken to machine shop to deck along with the block.

YotaBoy83

Alright thank you. I was thinking of going with the head gasket spacer but am leaning more towards the thicker head gasket for better reliability. It will be bored out either 20 or 40 over depending on what the machine shop says. But I also do have a 20r head so my compression will already be higher. And it will be getting a engnbldr cam and my parts I am ordering from them.

YotaBoy83

I did a compression check today I only had time for the number 1 cylinder I did forget to to have the throttle wide open but when I did it the cylinder cam out with 120 I then squirted oil in the cylinder and it brought the compression up to about 140 -150