Saturday, January 31, 2009

Detailing the Engine Bay, Over Time

Addendum July 2012:  Appended pictures of updated engine bay. New AC compressor, new overflow coolant hose, general component cleanup.

Addendum August 2010:  Appended pictures of new engine bay harness, routing details.

Part of the maintenance and upkeep that I perform on this car, has to do with the engine and engine bay look. In this month’s entry, I will outline what I (and others) have done to detail and keep this part of our cars, looking as good as possible, providing some added benefits as well.

Our car came from the previous owner with a well maintained and nicely looking engine and engine bay. However, I noted some room for improvement that I figured I would address over time, and have in fact proceeded to do so over the last two years. My goal was to not deter too much from the stock look, just to refresh it.

My baseline and current progress
This is how the engine bay looked like two years ago, not a bad baseline:

This is how it looks like today:

In some cases the changes are subtle, out of view, and not as apparent as when seen in person, as opposed to in pictures.

The following are discussions of specific areas and/or parts that have been detailed in the engine bay area on this car.

Air inlet pipe
One thing not stock on either of the pictures above is the absence of the air inlet hose which runs between the coolant bottle and the air filter housing. On 2109 this was replaced a while ago, and if not I would have done it myself for cosmetic and performance reasons. Both DMC and sell this, each respectively name it "performance intake" or "performance cold air input" hose. These kits replace the stock soft plumbing, along with the a manifold valve and feed. The removed parts existed to warm the intake air, upon start up, specifically for colder climate conditions. Since this is a car used year round in the Southeast, and most DeLoreans don’t run in the Winter, this is an area for improvement. There may also be advantages to removing the stock assembly, because the original valve assembly tended to restrict a portion of the air flow into the engine.

Cost: Approximately $30 from vendors, or there is something similar available at local parts store, but if you can, support our vendors – our cars need them to be around. This is a simple DIY project.

Coolant Bottle
If you are still running with the original plastic coolant reservoir bottle – change it. Not to improve the look of your engine bay, but as a good preventive measure. Those original bottles were prone to bursting with cooling system issues, the modern bottles are made of stainless steel, and look great in the engine bay.

Cost: Approximately $140. from both DMC and (but the latter includes the mounting brackets).

The “valley of death”(VOD) job.
A VOD job on our cars is a must do if you are not sure how long it as been since something similar was done. Essentially this is a clean up and preventive measure, for the top of the engine block. That area is not normally visible as it is directly covered by our intake system, but underneath there, our block has some deep cavities, that over time collect grime, leaves, twigs, miscellaneous parts that fall in, and in some cases even dead rodents(!). This same area, specifically the cavities, have been known to get eaten away with years of corrosion, and sometimes creating, or contributing to create, block damaging cracks and holes – thus the “valley of death” moniker.

The job is not that difficult if you are handy and comfortable with working on cars, but best left to qualified DeLorean vendors otherwise. There are great documentation topics of VOD jobs on, so I won’t attempt to cover it here, but I did perform this project on 2109, during July 2008 (and with online assistance and support from other owners, enthusiasts, and vendors). I summarized the entire experience in a short youtube video as follows:

As you can see from the video, this project is an opportunity to clean up the area, coat it with a protective paint, and even replace some potentially future trouble parts in that area (sensor, water pump, thermostat, internal hoses and their clamps). Some specific detailing performed were:

Under the intake, the top of the block.
The picture below shows this area cleaned (Simple Green, soft wire brush, dry off, repeat many times) now painted (POR-15), along with several replaced components.

Performing this job is also an excellent opportunity to clean up some parts that need to be moved out of the way, while this job is underway.

Rewired main harness – notice that in the pictures above there in an unobstructed view into the air mixture screws, above the intake W-pipe, or intake horns. This is because the main harness was re-routed to go under the passenger side of the intake. In a stock DeLorean the harness comes across and above the top of the driver’s side of the intake.

Cost: This modified harness (Part #:110185) is available from DMC for just under $200., but other owners have taken their original one apart and reorganized it, to accomplish the same effect.

Clean and paint components
The picture above also shows several brackets that were painted, they were originally black with grime and dirt. The intake manifold is a chrome plated Ebay find, that sat on my shelf for over a year awaiting this project. A good sandblasting and painting of your existing one, will most likely yield a major improvement to this prominent part on your engine bay.

The picture below shows a before and after of 2109's air mixture unit, cleaned as discussed above, and painted with Duplicolor Gold and Aluminum colors.

…and before and afters of the throttle assembly:

Cost: I suppose if you have this done, this could easily run well over $1000. in labor alone. As a DIY project, it cost me about $480 in parts and 75 hours (by myself, with some minor complications (seen in video), and I don’t work fast as I took plenty of breaks, and took lots of pictures, done on weeknights and weekends over a 6 week period. Others have done the basic work in much, much less time.

Valve Covers
They are very prominent in the engine bay, so these are on the top of a list for cosmetic improvements. The driver’s side is the most tricky to take out, because you have to temporarily relocate the bulky compressor with its lines attached, but overall this is just an unbolt, paint, bolt back on procedure. The picture below shows the passenger side cover after it was painted and reinstalled, unfortunately the air intake covers a large portion of this one.

Cost: I can only comment on a DIY solution and it was less than $20 for one can of spray paint, and some replaced bolts.

Ignition Resistors
Because of their location and its color, a cleaned up ignition resistor adds a nice tidy detail to the overall look of the engine bay.

Cost: Your time to scrub away, I used Simple Clean and a soft-ish wire brush to work off the grime.

Vinyl Caps
This is a relatively simple one, the AutoParts store sell a pack of PVC caps for about $5.00. These caps can be used on your door plungers, and also to cover up those two bolts on the left side of the bay (pictured below) and even the ground lug on the opposite side.

A/C Compressor
Another prominent part in your engine bay, is the A/C compressor. This is a tricky component to clean up or exchange, because it entails extracting and recoveing all the Freon, before you can disconnect the compressor. As I am doing, unless there is some major A/C service to be done I will leave mine as is - but this is definately another prominent part of your engine bay so it is definately an area to clean up.

A/C Idler Bracket and Pulleys
This one you can argue is both a cosmetic and an upkeep item. If you are running the original pulleys and bracket, chances are they can use a good clean up and your bearing may not be at their best. Replacing the bearings on the pulleys also yields a slightly quieter running engine.

Cost: You can do all this work yourself, but can send you the bracket and pulley as shown above, for about $50 plus shipping and a $100 core charge, which is refundable when you send him back your old bracket/pulleys. SpecialAuto's pulleys with new bearings, are definately not as noisy as my original 27 year old pulleys.

Engine Bay Light
Here's a quick project, how about replacing that old yellowed engine bay light? The merits of that light are debatable; however, since it's there may as well update it with a newer one.

Below is a before and after shot:

It's a subtle change, but it does overall contribute to a clean up.

Since I was going to replace this light, I decided to also incorporate a simple mod. I often find myself wanting to be able to turn off this light (daytime, engine lid up), and to do so, I'd have to unplug it at the switch (by the lid hinge) and remember to re-plug it. A better solution would be for the light to have a switch. The picture below shows a comparison of the orignal and the new housing with the light switch mod (also note comparative condition of conductive internal brackets).

Cost: New old stock lights are available from DMC (or your local DMC Dealer) as part number 100439, the current price is about $27.

Painting the Engine Bay
This is best done with the engine out of the bay, however, very impressive results have been achieved by a local Florida owner without removing the engine.
He documented the experience and results here:

Although not in my sights nor current plans, there are custom components available that can be integrated into your engine bay, for that different look. A short list of those are:
Stainless air cleaner unit (
Braided stainless fuel lines (, and DMC-CA)
Different color vacuum lines (cut to size as a kit, at
Nology kit, with beefier spark plug wires (DMC)
Custom stainless throttle cover (

So that’s it, as you can see with time, and a little elbow grease every now and then, you can make some visual improvements to your car’s engine bay. Many of these improvments are also good preventive measures, which will contribute to provide you with many more enjoyable DeLorean miles ahead.

Addendum 08/12/2010
There are often questions, and I had a bunch, of how to route the new engine bay harness.  Below you will find 4 pictures, the first my questions about routing prior to installing the new harness.  The next three pictures, address most of the questions of the first picture, as they are pictures after the harness was installed.  (You can click on the pictures for a larger view.)

Questions, questions, questions, I had....

How it turned out/answers...

------ If you have a few minutes, be sure to check out the "Best of" postings. Thanks.------