How to take care of this...

[achapman89]

I have an 88 t-bird block and a 90 mustang block. Which block should I have machined... The t-bird block is a little rough on the outside but it still has the crosshatching on the cylinder wall. The 90 block is all clean hatching still there. So I was talking with my Dad, we are thinking about the t-bird block and single plug head but swapping in the roller cam.

What does everyone think I should do, what combo of items should I do. DIS or EDIS? 1 plug, 2 plug? I know to take the roller.

 

[Dave R]

Is the '90 Mustang DIS?

Personally, after some minor experience with it, I'm leaning towards EDIS for my next toy. I definitely won't be using a distributor no matter what path I take.

 

[AllanD]

if the crosshatching is still clear and "brite" in the Turbo block why mess with it?

Run it as is....

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[achapman89]

Well the block is on a stand all cleaned up and bored .20 over. Got most of the parts to start putting this one together, but more questions are popping into my head (this being my first full rebuild) Do I have to make any changes with the balance shaft or is it just a gyroscopic thing?

 

[anupaum]

Well the block is on a stand all cleaned up and bored .20 over. Got most of the parts to start putting this one together, but more questions are popping into my head (this being my first full rebuild) Do I have to make any changes with the balance shaft or is it just a gyroscopic thing?

Balancing internal parts isn't always necessary, but I've always done it. If your budget's not too tight, I'd recommend having it done.

 

[Dave R]

Do I have to make any changes with the balance shaft or is it just a gyroscopic thing?

Balance shaft? Gyroscopic thing?

If you haven't made any significant change to any of the rotating (i.e. lightened the crank or flywheel) or repicrocating (i.e. changed to different rods) assembly then there is no need to re-balance anything.

 

[D94R]

That is not a balance shaft, it's an auxiliary shaft used to drive the distributor and oil pump, and later on it was used only to drive the oil pump. (unless its a Cali engine, then it served as place for the cam position sensor as well)

You shouldn't have to worry about re-balancing any of the bottom end until your quest for high HP comes into vision. Even though you are going with new pistons you should be OK for a stock to mild build up to 300HP or so.


If you can get EDIS setup on your engine, then I'd suggest that, however the base timing will not be adjustable without some way of tuning it. It will also require VERY PRECISE installation of the front seal cover on either block.

 

[AllanD]

On a 4cyl inline there is NO "bobweight" balancing like there is on a V-engine.

the important thing to remember is that the pairs of cylinders counterbalance
each other.

So if the #1 rod and piston assembly weighs nearly the same as
the #2 piston and rod assembly
AND the #3 & #4 assemblies weigh the same as each other
It doesn't actually matter if the #1-#2 set is the same weight
as the #3-#4 set weigh.

The piston and rod assembiles must be balanced in pairs
and the actually pairs can be different weights without
upsetting the balance of the engine as an assembly.

On an inline 6cyl the assemblies must be balanced in sets of three.

On a V-engine ALL must be the same weight AND must be properly matched with the crank counterweights and even then the engine might not be actually "Balanced" for smooth operation at all rpm! In other words a Vengint will usually have SOME rpm where it will vibrate even if the balancing is right on.

The trick is setting up the engine so that the vibration occours at an rpm where the engine won't be used "steady state" at that rpm.

Anyone familiar with the "cologne drone"? the tendency of Ford "Cologne"
V6 engines(particularly the 2.8 and 2.9) to vibrate at between 2800 and 3100rpm?

(Just for illustration purposes)
5.0 fords tend to vibrate themselves apart if run for any length of time
at above 6000rpm
This is particularly devestating because it coincides with the natural
harmonic frquency of the "Duracast" crankshaft, which leads to a progressively
increasing "index distorsion" which feeds the vibration further and
eventually crank flex tries to pull the main webs out of the block
OR breaks the crank. the problem can be ELIMINATED by running
a steel crankshaft, OR running an early "mexican" (thicker walled)
engine block rather than the later "lightweight" blocks.

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