How to deck a 4 Cylinder Engine Block
 

How to Deck a 4G63 Block



The block is a 7bolt 4G63T

The block was brought in to be prepped for rebuild.

It has been Bored and Honed to .020 over std.

Checking the block I found it had .0025 taper from front to back and has water pitting.

I set the block on the machine fixture; the block is on the main saddles.

I make a .0005 pass, Cyl #1 is shorter than Cyl # 4

https://www.miataturbo.net/attachmen...ine=1332881558
I see I have a good level set up side to side, notice the dark low spots around #1 cylinder.
A MLS head gasket will not have had a good sealing surface.

[https://www.miataturbo.net/attachmen...ine=1332881558

Pass #2 is a .0015 cut
https://www.miataturbo.net/attachmen...ine=1332881558

Still some pitting at the fire ring of the head gasket.
https://www.miataturbo.net/attachmen...ine=1332881558

One more pass of .0015
The block looks good, and has a good head gasket sealing surface.
https://www.miataturbo.net/attachmen...ine=1332881558

Post more of this machining ----. I like it.

This!

Guys... Thanks! Glad you like them!

I am tryin to post 1 a day for a bit.

If there is a specific machine shop procedure you would like to see , let me know and I will see what I can do for you.

Maybe document a complete build? From grimey stock motor, to built block with fancy go-fast parts, with all the steps in between? Hot-tank, cleaning, assembly, boring/honing, head decking, headwork etc. No particular order there though.

+1

Having never been in a machine shop, and having never built a motor, a lot of this is still voodoo to me.

Can you show more how the block is attached to the machine?

I have a deck checking micrometer to check distance from mains to head to be sure the deck is the same end to end. This matters to be sure the cylinder volumes are the same in all cylinders. Keep the compression the same. The line bore has to be correct first of course.

I'm digging that you are showing us the process. In fact, I've been digging a lot of your posts recently. If I had access to this information years ago, it could have saved me about $2k on a 5.0 rebuild that went to ---- due to a shitty machine shop. Keep up the good work!

^^ This. I'd love to build an engine, but I have no idea how to set clearances and crap for pistons and rings and bearings and oil pumps and blah blah blah ghjkasdenu... In my limited experience the machine work is not exactly super pricey, its the assembly that kills you.

Oscar... In my intro to this fourm, a customer pointed me here for his build that I am working on, so from grime to shine will be seen!

Devin &E02K Part of the reson I post this type of info is so the guys that have not built an engine know what to look for in a machine shop in there area. What the machining procedures are for diffrent parts. So then they can do the best build they can.

Soviet.. If I would have seen your post earlier, I would have got a pic so you could have seen how they set up, I just milled blcks today, 3 of them, Mitsu 4G63T, Honda H22A1 and a Mazda 1.8 :D

Alta, you are right, everything is based off the mains, the set up I use for decking a block and boring a block, the machines require that the block is set up on the mains.

Thanks for these threads.

I am in Pcola. Adopt me.

JasonC.. You are welcome, I have more to post, Hope you learn something a new!

Tasty danish..... I might know you, I do a fair amount of work for the Navy guys around here.

I technically live in Milton and have a machine shop up here doing a basic valve job on a VW head. Other than that I haven't taken anything to a shop. Do you have a place or work out of your garage?

Once there are a few more of these, I vote they get their own sub forum. Thank you, Dale, for shining light on this voodoo.

Skidude.. Your Welcome!

I have more than a few more to post!

I prefer these separate threads a lot more than one humongous thread about a full build.
The natural comments about each step in the process would make one complete thread pretty hard to navigate.

With individual threads of the steps one can always make a sticky linking them together.

Keep 'em coming :bigtu:

I agree maybe it can be setup like the megasquirt sticky

Thread with general info... additional info

Process in order

1) Link
2) Link
3) Link
4) Link

Decked the 1.8 BP Block
 

It had a couple areas I was concerned with as far as gasket sealing goes.

You could see where the HG fire ring had dug into the block deck.

i took these picks when i was decking my miata block, im gonna post them over in the engine maching overview thread too.
https://www.miataturbo.net/attachmen...ine=1333889326
https://www.miataturbo.net/attachmen...ine=1333889326
https://www.miataturbo.net/attachmen...ine=1333889326