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Engine block prep for rebuild

To: road <datsun-roadsters@autox.team.net>
Subject: Engine block prep for rebuild
From: Thomas Walter <twalter@austin.rr.com>
Date: Thu, 19 Jun 2003 18:20:10 -0500
Scott,

On the Engine Block... I am a stickler for little things. Should
not be surprising to the list.

I have found all sorts of "junk" in every cavity AFTER the engine
came back from the machine shop. Older cleaning methods was to
"hot tank" the block is a vat of degreaser. REALLY OLD degreaser
was lye (nasty stuff, and would eat the camshaft bearings right
up). Newer shops use a "pressure washer" that looks like a oversized
dishwasher.

After hot tanking... best to have the camshaft/jackshaft bearings
replaced. Let the machine shop handle that, but TRIPLE CHECK their
work. Rear bearing for the U20 Jackshaft has three oil holes, same
bearings for a R16 have TWO oil holes... that is the feed hole for
the cylinder head. Nasty stuff happens when the bearings are installed
wrong, covering a hole, or wrong bearings are used.

BEFORE the engine goes in:
Drill out the front oil galley plug. My trick is to drill a 1/4" hole.
I used a long 20" rod (came from a scrapped printer, hardened steel 
rod). Through the front hole, insert rod and knock out the back plug.
Now flip rod around, as there is enough room to catch the edge of the
front plug... knock that galley off.  DO NOT FORGET TO REPLACE THE
PLUGS!!! before final engine assembly.  [I'll tap the ends for a
threaded plug, but if you are not sure about holding a tap straight,
the OEM type plugs are easier to reinstall... ASK the list before you
do for tips on installation]

MAIN BEARING CAPS: Bolt back into place on the block, and torque to
specs. Shop will know they are dealing with a pro! <grin>.

ALL BOLT HOLES: Use a 90 degree chamfering countersink. Just remove the 
top edge of the bolt hole. CHASE all threads. The "metric" headbolts 
will seem to be a really odd size, until you discover they are 7/16" - 
14tpi. With a DENTAL pick I'll scrape the bolt of the bolt holes, 
keeping my shop vac handy. I've done this BEFORE and AFTER machining...
and was shocked to find out how much crud was in the bolt holes.

BOTTLE BRUSHES: You've knocked out the oil galley plug, time to scrub 
the galley with bottle brushes. Ditto on all oil passages. Keep a note
book and record every hole into and out of the camshaft/jackshaft. If 
the shop is going to replace the camshaft bearings, do this BEFORE the
block goes in. Confirm all passages are correct when the block comes 
back with the near bearings installed.

So your nice block is back from the machine shop. Get lots of WD-40 
(hand sprayer, I buy one gallon bottles), tons of PAPER TOWELS, scrub 
brush, heavy duty rubber gloves, TSP (tri-sodium-phosphate) cleaner.
Engine on a wheeled stand.

Roll the engine to the end of the driveway, water hose ready. WD-40 
ready. Bucket of "hot as you can stand it" water, mix in TSP. Start 
scrubbing! Spray WD-40 on all machined surfaces as you go. Never let 
water dry on a machined surface unless sprayed. Just prevents rust. Oh, 
I have my air hose and nozzle to "blow out everything". Yes, goggles in 
place. Have fun. Scrub, rinse, scrub rinse, squirt WD40. That block will
be spotless. Rotate block around on the engine stand to get to every
side. Little more WD40 on the machined surfaces... wheel back into the
garage once fully dried. Block is ready for painting. Odd part, I found 
a LIGHT MIST of primer (sherwin williams) first, then the engine block 
color. Admitted the primer isn't "engine proof hot", but a light mist 
coat helps keep the top coat in place for years to come.

Whew... any questions?

Tom

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