Engine Rebuild - Completing the Shortblock - Step 4
By Ryan Ballou
As you may start
noticing, building an engine can be a slow process. There are quite a
few steps to take and multiple trial assemblies or mockups are to be expected.
In this article I'm going to cover the steps that will leave you with
a completed shortblock, sans flywheel.
Even though we already gave the case a thorough once over, there are still
a few areas that will need attention that couldn't be dealt with before
now. First off, you need to have your oil pump ready to go. The way the
oil pump fits in the case is an area of great concern to ensure flawless
oil delivery to the engine.
Since this engine will use a full flow oiling setup, a pump with a plugged
outlet and a full flow cover will be needed. When it comes to choosing
pumps, there's really only two choices as far as I'm concerned when you
the majority of your driving will be on the street, a Schadeck pump with
either 26mm or 30mm gears. My personal favorite are the pumps modified
at Gene Berg Enterprises (GBE) as well as their cast iron full flow covers.
They modify the pumps by porting the intake side to reduce flow restrictions
to the pump. Next the pump bodies are cut for an O-ring to ensure a good
seal with the case bore. Then the pumps are hard anodized to prolong their
life and reduce wear. Finally, the pump bodies are decked to effectively
set the gear end float to zero, not accounting for the gasket. Their pump
covers are cast iron to promote long life and minimal wear, and surfaced
to be perfectly flat. What this all means is that you end up with a pump
that will produce as much flow/pressure as it can and still live a long
Now what you need to check for is that inlet hole in the pump aligns with
the inlet hole in the case. Take the case half that has the oil pickup
tube installed in it. Set the oil pump in place and slide it into position.
You may want to use a couple of nuts and washer (finger tight) to hold
the pump hosing in place. Look down through the gear housing to see if
the holes are lined up. You can also stick a finger in there to feel for
a lip if the holes are off. If there is an alignment problem with the
inlet hole from the case to the oil pump, you can use your Dremel with
a rotary file open up the hole in the pump and/or case and make the holes
Another very important area to check is from the rear of the pump housing.
Some newer cases have their oil supply holes bored so close to the cam
gear area that the pump body cannot sit far enough back in the case to
line up with the hole. This is where having the O-ring on the pump body
is a real nice feature. If it's severe, you can have your machinist take
some meat off the pump body flange to allow it to sit deeper in the case.
If you have to have this done, be sure to recheck cam gear bolt to pump
With the pump squared away, it's time to check your deck height for the
first time. This will require you to do a trial shortblock assembly. That
means set the crank/rods in place, but leave out the cam, lifters and
pump for now. Bolt the case halves together and install your pistons on
the rods. Make sure you remove the piston rings first. Slide the cylinders
over the pistons and you're ready to continue.
You'll need to have your degree pulley and you'll also need a deck height
tool. You can either use one that works with feeler gauges or a dial indicator;
my preference is a dial indicator. Check the deck height on each of the
four cylinders. Usually all the numbers will very close to the same value.
If you want, you can mix and match pistons and cylinders and you'll find
that the numbers change. This is due to slight variations in the manufacturing
process. After a little trial and error you should be able to get all
four numbers to within a couple of thousandths.
The reason you're checking deck height on a trial assembly is so that
you can find out if you need to have your case decked. It turned out that
my deck height with no spacers installed was about .090" and I was
aiming for .050". That meant that my case had to be torn back down
and sent back to the machine shop to be decked .040". If I'd gone
ahead and used sealer and done a final assembly before taking this measurement,
then I'd just have that much more work to do cleaning it up and doing
With your deck height squared away, you're in the clear to assemble your
shortblock. Above and beyond all else, this means CLEAN, CLEAN, CLEAN.
Your crank and rods should already have been cleaned prior to their assembly
and bagged whenever they weren't in use, but your case has been through
quite a bit since you first cleaned it up and inspected it. Clean it to
the point where you could eat off it, and then do some more. Apply assembly
lube to all the lifters and set them in place. Use lifter retaining clips
on the case half that you 'drop' on. Now use the cam break-in lube provided
with your camshaft to all the lifter heads and cam lobes. Set the main
bearings and cam bearings in place and smear them with assembly lube.
Drop the crank in first and then the cam, making sure to line up the timing
gear dots. Now is also a good time to install the distributor drive gear
because if it drops and is a tooth off, it's much easier to remove and
reinstall with the case split. Don't forget the two washers under the
drive gear. Finally, install the O-rings over the six main studs.
With the crank/rods, cam, lifters and distributor drive gear in place,
you're ready to go. Apply sealer to the case halves sparingly. My favorite
is called Aviation Form-A-Gasket and is marketed by Permatex. Sealer should
be applied sparingly and only where needed. The only purpose it serves
is to fill the small voids, scratches, etc. in the mating surface, so
don't over do it. Keep it away from main bearing saddles and be careful
around the cam bearing halves near the end plug. Sealer can squish out
and actually get into this bearing if you use too much or get it too close
to the saddle. I also use a little sealer on the cam plug regardless of
what type it is, i.e. grooved or smooth (rubber).
You have some working time with this sealer, but still try to work quickly.
Carefully drop the case half over the main studs and have a helper work
the number one and two rods into their respective bores. When everything
is good, the case half should drop right into place leaving 1/8"
to 1/4" gap around the parting seam. Hand-tighten the six main studs
and slowly pull the case halves together. Stop frequently and make sure
the crank still moves freely. Don't actually spin the crank or you can
damage the distributor drive gear, but rock it back a forth a little.
If you feel any binding, stop and check for a pinched dowel on a main
bearing. Once the halves are pulled together completely and you're sure
the crank is moving freely, you can torque the six main studs and the
two 8mm main studs at the nose of the crank.
Now before tightening the rest of the case studs, install the oil pump
housing. It's much easier to install now before you tighten the case nuts.
I use the same sealer I used on the case to do the oil pump and omit the
gasket. Set the oil pump gears in place and pack the cavity with some
assembly lube to help prime the oil system quickly. Use a very, very light
smear of sealer on the face of the pump body outside the groove making
sure to keep the groove clean and clear of sealer. Set the thin gasket
in place and smear a little more sealer on the gasket before installing
the pump cover. Install the nuts only hand tight for now.
Return to the case and begin by tightening the nuts on the two long studs
at the cam bearing nearest the flywheel. Then work your way around the
perimeter of the case. Now go back to the main studs and re-torque them,
then do the same for the case nuts. Repeat one more time and you're done.
Finish by tightening the oil pump cover nuts. The reason you check the
torque three different times is because as the sealer is squished out,
the tension on the case studs diminishes, essentially loosening them up.
With the exception of the flywheel, what you have now is a shortblock,
the heart of your engine. It's a good idea to drop in a distributor right
now to prevent the drive gear from trying walk out and getting damaged
if and when you spin the crank. Since you still have large open hole in
the case where the cylinders go, it's a good idea to use a large trash
bag and wrap the engine up whenever you're not working on it. I will also
use some masking tape on the smaller holes to keep things clean. This
will help to keep and debris from entering the engine.
1-It's the alignment
of these holes that's so important. Make sure there are no restrictions
to flow here. If they don't line up, make them.
2-Checking the deck height is quite easy with the right tools.
It's good practice to write down your numbers so you don't have to
remember them. In this case, the piston made a good notepad. Also
take note that I numbered the cylinders, this is because once you
get the pistons and cylinders matched up, you don't want them to be
accidentally separated. Finally, this is the time to verify your degree
pulley is accurate. Use the dial indicator to find top dead center
(instant the piston stop traveling upwards) and check to see if the
degree ring on the pulley is true.
3-Bearings and lifters are in, lubed and ready to go. The sealer is
dark brown in it's container, yet here it looks yellow. It's because
of thinly it's been applied, don't over do it. Also take note how
I avoid the area around the number one main bearing. Any sealer there
could keep the case from applying proper 'crush' to the bearings.
The few dark spots visible in the sealer were wiped down before continuing.
Careful with this stuff, it ruins clothes and only cleans up with
4-Everything installed and ready to go. Some argue that you only need
sealer on one case half, not both. I prefer using it on both sides,
but making sure to keep it thin. Don't forget to install the bevel
washer and woodruff key at the nose of the crank.
5-This is what happens if you use too much sealer, assembly lube,
or both. A little lube squeezed out into the case halves. This could
have caused a leak. If too much sealer is used, it can also ooze into
the bearings, even worse than a leak.
6-Unfortunately my oil pump wasn't ready in time for this picture,
but here we have the completed shortblock. A little tape over any
openings and caps on the oil fittings will help keep things clean
until the next step.
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