This posting is one in a series. If you have not yet read the earlier postings in the series, you’ll need to, as this posting won’t make much sense without having done so! Just do a search using the word “SLURP”.
In my last posting I described that incredible evening when I realized all the expertise and experience I was tapping into.
In this posting, Red’s new salvaged Cadillac LQ9 LS series engine gets paint!
The LS series engines have many alloy parts on them, but the blocks come in two varieties: alloy and cast iron. The alloy ones are used in applications where lighter weight is a requirement or advantage, while the cast iron ones are used where greater strength and / or greater overbore capabilities are desired. Interestingly, at least one performance shop, Livernois, prefers the cast iron blocks for detailed dyno testing, due to the cast iron block’s more consistent temperature under conditions where multiple sequential tests are being run in a dyno setting.
Red is getting a cast iron block, even though I would have preferred an alloy one for this application. Light weight is one of the guiding objectives for the SLURP project, but on the salvage market, the only 6.0 liter version of the LS engines that is alloy is from recent Corvettes, SSRs, and Trailblazer SSs, and commands a price premium because the young inexperienced rodders out there all want it. The cast iron LQ9 (not LQ4) version out of the Cadillac Escalade and the Silverado SS pickup is very desirable to a knowledgeable buyer, and goes for way less money. Since the only differences beyond block material are items I am changing anyway, the cast iron version is an absolute bargain. The weight penalty is 65 pounds.
At any rate, the reason for describing all this is to draw attention to the fact that the block is cast iron, and therefore needs a paint finish to prevent unsightly rusting. GM ships the LQ9 engine with its block painted black. But, that finish was showing some aging on the salvage engine, and I also wanted a bit more pizzaz. So, I decided to repaint it.
Most of the tools and supplies needed are shown in this photo:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Paintingthenewengine001suppliesandt.jpgI needed:
Brakleen: a brake cleaning solvent that leaves absolutely no residue (conventional solvents leave a residue that can later leak out of crevices and can interfere with the paint finish)
Paper towels (lots): To use in conjunction with the Brakleen, and also to roll into small “plugs” that protect orifices (like the dipstick tube mount point) against getting paint inside the engine
Mini wire brushes: To properly remove rust and to condition the metal surface to better hold the paint. Note the two different shapes and sizes, which enable handling all the various contours encountered on the engine block, including very small nooks and crevices
Electric drill: To provide horsepower to drive the wire brushes
3M “blue” masking tape: This 3M tape is used for masking off areas we do not want to get paint onto. It is especially designed for this type of work, and leaves no residue when removed
Scissors: To easily cut the tape to whatever special dimensions and shapes might be needed
Newspapers: To provide coverage against overspray. The newspapers are taped to, and taped by, the 3M tape, and work in conjunction with the tape to provide 100% coverage of areas we don’t want to either spray or overspray
Engine enamel: I used Plasti Kote engine enamel, good to over 500 degrees. Some folks use barbeque paint, which varies but can be good to as much as 1400 degrees. The guys at the auto parts store pointed out that if the EXTERNAL surface of the block gets past 500 degrees, you’ve got much more serious problems to deal with than burnt paint. I needed very close to one full can, but as you can see in the photo, I bought two just to be sure (running out part way through the paint job would be really dumb).
The procedure was tedious but simple:
- Make absolutely sure you have GREAT ventilation. The Brakleen, the mini wire brushing, and the paint spraying all produce vapors and particulates that have no business inside your lungs!
- Remove all accessories (like oil cooling lines, water pump) that prevented clear access to the engine block, or were too hard to protect against overspray
- Plug all orifices with plugs made from rolled up paper towel pieces (this is VITAL as both wirebrushing and painting produce material you don’t want inside the engine!)
- Vacuum the exterior of the engine to remove dust and grit that would interfere with painting
- Pre-clean the block surfaces with Brakleen and paper toweling. This CRITICAL step ensures that all loose dirt, and all grease, is removed before applying the mini wire brushes. Grease would clog the brushes and also be spread and sprayed by the brushes throughout the block surfaces if not removed FIRST! Dirt would be sprayed everywhere, into nooks and crannie where it would be a hazard during later internal work on the engine.
- Use the two different mini wire brushes with the electric drill to thoroughly derust and “etch” the block and old paint. This creates a significant amount of loose residue
- Vacuum the engine surfaces again thoroughly
- Clean again with Brakleen and paper toweling
- Mask off all areas that should not get paint. Use the 3M tape to delineate precisely the cutoff lines, and then use newspapers taped to that tape to cover large adjacent areas. Paint overspray travels much further than most people think, so I basically covered the entire engine and engine stand with tape and newspapers. Here’s what it looked like just before paint spraying:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Paintingthenewengine002enginemasked.jpg- Shake the paint can really well, for two full minutes, and then spray coat the unmasked areas using many thin coats versus one thick one (to prevent runs). Shake the can again every 30 seconds or so during the painting process. Be sure to spray from multiple angles, so that the coating is consistent on tops and bottoms of ribs, and gets properly into tight crevices. Resist the temptation to spray heavily where crevices are resistant to proper paint application. Instead, re-spray OFTEN in THIN targeted applications. It WILL cover.
- Invert the spray can and spray to clear the nozzle, when pausing the painting for more than a few seconds. This keeps the nozzle from clogging.
- This is what my engine looked like at this point:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Paintingthenewengine003paintapplied.jpg- Let the paint dry to the touch (touch an oversprayed area, not the engine block, to test!!)
- Carefully remove all tape and newspapers
- Here is what the end result looks like:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Paintingthenewengine004unmaskedandc.jpgWhich certainly has more pizzaz than how it looked before:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Valueofexpertiseandexperience005eng.jpgHopefully, I did everything correctly, and the paint will prove to be as durable as it now looks!
Jim G
