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Used Engine

High compression of the IDI diesels is so they start in cold weather with the low pressure "primitive" injection systems. The Precup and chamber take a lot of the heat away so compression was increased to make up for it. Lower compression means white smoke and misfire while the engine coughs to life on a cold morning.

You are building stock so there is no reason to mess with it. However by the stamps on the connecting rods indicating a rebuild you do need to check and see if the block was decked and actually requires the thicker head gasket. Did the old gasket have any part numbers on it to make it easy to track down?
 
Until a couple years ago, I was always a fan of the highest compression ratio possible for easier starting and what seemed to me like a longer theoretical life because of ring wear and compression losses. Also higher compression meant less boost pressure needed from turbo.

A lot of reading and talking to folks brighter than me showed me the err of my theory.

The older engines were 21.5:1 optimizers are 18.5:1 (maybe 18:-?). So does that mean the optimizers are that much harder to start or die sooner as the rings wear when the compression ratio hits that magic “too low” number?

By the time the rings and cylider walls get enough wear to drop the compression- 1 single time of getting hot does way more damage. The lower compression means less fight with every revolution. Letting the turbo work harder is better and cheaper than making the lower end work harder.

If you do new rings, properly fitted, especially gapless, the compression gains from that would exceed the thicker gasket long term.

As for stock running the thicker gaskets, there is a theory that thicker gasket is greater cross section giving more area for the ignition fire to do damage and blow out easier- but with fire rings as high quality as they are nowdays- no concern at all. The extra ten thousandth is no bigger imo.

There is the thought of the valves not opening a touch as far, but being stock your not fighting for every last ounce of power anyways. You’ll never notice the difference of the valves not going open that last touch.

I would say run the thicker ones if not sure.
 
WarWagon said:
High compression of the IDI diesels is so they start in cold weather with the low pressure "primitive" injection systems. The Precup and chamber take a lot of the heat away so compression was increased to make up for it. Lower compression means white smoke and misfire while the engine coughs to life on a cold morning.

You are building stock so there is no reason to mess with it. However by the stamps on the connecting rods indicating a rebuild you do need to check and see if the block was decked and actually requires the thicker head gasket. Did the old gasket have any part numbers on it to make it easy to track down?
Click to expand...

I haven't pulled the heads yet. Planning to do it this weekend.
 
Will L. said:
Until a couple years ago, I was always a fan of the highest compression ratio possible for easier starting and what seemed to me like a longer theoretical life because of ring wear and compression losses. Also higher compression meant less boost pressure needed from turbo.

A lot of reading and talking to folks brighter than me showed me the err of my theory.

The older engines were 21.5:1 optimizers are 18.5:1 (maybe 18:-?). So does that mean the optimizers are that much harder to start or die sooner as the rings wear when the compression ratio hits that magic “too low” number?

By the time the rings and cylider walls get enough wear to drop the compression- 1 single time of getting hot does way more damage. The lower compression means less fight with every revolution. Letting the turbo work harder is better and cheaper than making the lower end work harder.

If you do new rings, properly fitted, especially gapless, the compression gains from that would exceed the thicker gasket long term.

As for stock running the thicker gaskets, there is a theory that thicker gasket is greater cross section giving more area for the ignition fire to do damage and blow out easier- but with fire rings as high quality as they are nowdays- no concern at all. The extra ten thousandth is no bigger imo.

There is the thought of the valves not opening a touch as far, but being stock your not fighting for every last ounce of power anyways. You’ll never notice the difference of the valves not going open that last touch.

I would say run the thicker ones if not sure.
Click to expand...

I am going to do gapless. So from what you're saying if I can't find the part number for the existing HG I should just go with the larger HG.
 
Without the information of if your block and or heads were machined- YES use the thicker gaskets.
You could get to the measuring and determine if the heads or block was cut but since there are no real drawbacks imo to running the thicker ones, do it.
 
Will L. said:
Without the information of if your block and or heads were machined- YES use the thicker gaskets.
You could get to the measuring and determine if the heads or block was cut but since there are no real drawbacks imo to running the thicker ones, do it.
Click to expand...
Thanks Will! that is what I was thinking.
 
Will L. said:
Yes. Same location and which side is up

What I do is paint marker top side and just stick all 16 in a piece of cardboard and mark which end is front of engine.
Click to expand...

I don't think I have that many different colors. I'm thinking of using some masking tape and mark the cylinder and a/b that they came out of.
 
Cardboard box closed up. Put 16 holes in the box top. Mark box front of engine and then put pushrods in order into holes and make sure you keep top and bottom unF'd. The top is hardened and the bottom isn't so upside down wears out fast on the rocker. Pushrods can be full of oil so you may need to drain then a min. Rags in box to catch drips.

2nd box mark front of engine and take rocker assemblies out and keep in order in box. Work on one at a time to replace buttons then put on engine.
 
F5A4BF98-86F4-402A-A1C6-9C47ACE3C2FC.png
Something like this is what you are imitating. A shoe box works good. Just label which is front of engine and stab 8 holes on left and 8 on right.

You only
Need one color to mark top of pushrods. Oh you’re identifying is top from bottom. If you clean oit good enough,
Tape works.
Keeping the lifters in exact spot is common practice but not as important on roller rockers.
 
Thanks guys! I just wiped them down good and blew the oil out. Put tape at the top and labeled. Where are the plastic retainers located. I don't see any.
 
I got the heads off. What is the easiest and safest way to get the residual head gasket off?
Also There is a little carbon on the cylinder head. I know I can clean it off with carb cleaner but if there are a couple of stubborn spots can I use a wire brush or a media blaster?
 
Fairly coarse. You don't want to polish the surface. Also don't get to carried away trying to get every last bit off. You can make the surface uneven if you grind in one spot to much. I'd start with a razor blade and then use the disc after that
 
ak diesel driver said:
Fairly coarse. You don't want to polish the surface. Also don't get to carried away trying to get every last bit off. You can make the surface uneven if you grind in one spot to much. I'd start with a razor blade and then use the disc after that
Click to expand...

When you say fairly coarse, 40 and 80 grit sand paper is considered coarse. I don't want to screw them up.
 
I don't think you can get the roloc disc that coarse but I'd consider it if they did. The surface on the head and block is actually pretty rough. I believe there's actually a spec on the surface that most surfacing machines meet to aid in gasket sealing
 
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