[DML] Performance Engine Rebuild

[Jim Reeve <dmc6960@xxxxxxxxx>]

Hello there DML folks.  Been a long time.  For those of you not on
DMCTalk, I thought I'd let you in on what I've been up to the past
year.

Back in 2006, I spent all spring rebuilding the entire A/C system.
That ended up being way more adventurous than it should have, but
thats another story.  It ends with me getting everything back together
less than a week before DCS '06.  Unfortunately for me, an exhaust
manifold stud broke off on its own sometime over the previous winter,
and thus a quite loud and annoying exhaust leak developed within a day
of driving the car again in '06.  Not wanting this for the drive to
Chicago for DCS, I implemented a quick and dirty patch with high-temp
epoxy surrounding the exhaust gasket at the leaky port.  This was
sufficient for the trip, as it was nice and silent up until returning
home.  Now with the exhaust leak prevalent again, I lost enthusiasm
over driving the car, and it only sporadically was on the road
throughout the next 2 years.

Fast forward to spring of '08, and I decide to tackle the process of
repairing the manifold leak.  Due to only sporadic opportunities to
work on it, it as well takes all spring to accomplish.  Again, a week
before DCS '08, I get the car up and running.  Nice and quiet now, I'm
excited to take it on its next cross-country trip.  I go to change the
oil on the car, and to my surprise the oil is accompanied by a large
quantity of coolant!  Not good.  Not sure when that started happening.
 My previous oil change was early spring of '07, so anytime in between
is fair game.  Towards fall of '07, I was getting some engine
temperature fluctuations in which I discovered I needed to add
coolant.  That is my best guess to when the leak started.  However now
very depressed that I cannot drive the car to DCS, I decide to cancel
the trip as I really didn't want to show up not in a DeLorean.  That
is a decision I still kinda regret, as I've been to every DCS except
Cleveland '98, and now Gettysburg '08 can join that list.

This spring, in April of '09, I pulled the engine out of the car.
Throughout May I disassembled and began cleaning the engine
components.  I discovered the leak point being the cylinder liner
seal/shim where the liner sits in the block.  Part # 102614-102617.
This is a paper-thin gasket that seals pressurized coolant from
non-pressurized oil.  I had a large leak in cylinder #6, and a slight
one in #3.  Now knowing that I have no actual bad components, I toss
and turn in my head if I want to rebuild a stock engine, or use this
opportunity to build it up a little.  Well I chose the latter, way
latter, and built it up a LOT.

Here is the lowdown of all new parts/mods....

Higher compression pistons (9.8:1) from DMC Europe.
Milled heads by 1mm to bring total compression to about 10.7:1.
Entire rotating assembly rebalanced.  (Pistons were lighter, so the
crankshaft is now too).
Fast Cams from DMC Europe (these are milled to actually re-time them
for a 1mm head shave!)
Porting of the heads, this included filling in and removing the EGR
lump, and overall opening of the intake and exhaust ports.  It was
done with a flowbench.
Lightened the flywheel by a little over 3lbs.
Removed the deceleration valves on the throttle plates and soldered shut/smooth.
DMC Stage I Stainless Exhaust with Nology ignition system, new coil,
K&N air filter, and cold air intake tube.

I got it up and running last weekend.  And run it does!  Its like (and
practically is) a whole new engine!  Idles nice, revs nice, drives
nice.  Gets good mileage too, first approximation is around 27.4mpg.
I drove the car down to Chicago this past weekend and it worked great.
 Car rolled over 100k miles, so my odometer is approximate for the new
engine now!  Stopped at DMC Midwest, Dave checked out the engine,
likes it.  Stopped in the Dells on the way home and Dennis checked it
out as well, he wants to do this to his car now.  I have not dyno'd it
yet, and probably wont this year.  It *should* be getting between
170hp and 180hp at the wheels, which would equate to somewhere around
200-220 at the crank.  Thats more than a DMC Stage II.  This is still
a 2.8 odd-fire PRV.  I'm contemplating installing an EFI system in it
over the winter to complete the rebuild.  But for now I'm driving it
with K-Jet and enjoying it.  The total cost was less than a Stage II
crate engine, but not by too much.

The complete saga of the rebuild, along with photo goodness, can be
found on the DMCTalk thread located at...
http://www.dmctalk.com/showthread.php?t=12997

Just want everyone to know I'm BAAAAACK!!!!!!!!!!!!!
---
Jim Reeve
DMC6960
MNDMC - Minnesota DeLorean Club


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