Cylinder Head

So its finally time to work on the Cylinder Head.  The main work will be farmed out to a machine shop, but I did start to pull the studs out.  Stay tuned for a set of  "after" pictures.

 








After about a week, I got my cylinder head back from the machine shop.  It looks great and I can't wait to get it back on the car.  Full valve job, machined surfaces, new valve seals, and new intake valve seats (hardened steel).  The guys at Per Race Engines (http://per-race-engines.com) did a great job.

 

 

Block cleanup and preparation for assembly

So after dealing with all of the nasty gunk within the engine, finally I'm able to take some pride in getting ready for rebuilding the L24.  I decided to go with Pontiac Blue, which is a very very close match for the original Datsun block.  I also picked up some high heat primer and top coat for the exhaust manifold.

Here is the block being primed and final coat painted.  Please note that I did tape off everything very well that I did not want paint getting on.  For any overspray, I was able to easily clean it up with mineral spirits.

 

The exhaust manifold was quite a mess, and after a thorough cleaning, priming, and painting it was ready for its high-temp curing process on the BBQ. 20 minutes at 200 degrees, 30 minutes to cool, 20 minutes at 400 degrees, 20 minutes to cool.

Next came the freeze plugs.  I chose to go with the brass plugs and not paint them, I've seen this look before and liked it. While I was at it, I tapped & cleaned all of the threads on the block to get ready for reassembly

Some may say I did it backwards, but I left the deglazing of the cylinder walls for last.  I picked up a Flex-Hone which worked very well to take off a very minimal amount of cylinder wall glaze.  I feel I did achieve the 45 degree cross-hatching required to allow the new rings to seat properly.  Following the 20-30 seconds per cylinder, I washed the block thoroughly with water & soap, and then dried it with compressed air.  Lastly, I treated the unpainted surfaces of the block with ATF which also aided in the removal of the fine dust created during the deglazing process. Check out this YouTube video for more info on the Flex Hone: <<LINK>>

Next up will be rebuilding the bottom end with the new toys I received the other day...

Degreasing & Cleanup

So the messiest job is of course degreasing all of these parts that I've removed.  I thought the block was bad, and then I moved onto the oil pan, and the pistons were definitely the toughest with all of the carbon build ups.  I've been using Simple Green, WD-40, Mineral Spirits, and Gasoline as solvents.  Pretty good results, just takes time.

  

Engine Rebuild: Part 2: Engine Tear Down

Thanks to my wonderful core leave, I was able to tear down the engine to nothing.

First the head came off.  I did break one head bolt off into the block, but after some heat and elbow grease I was able to get it out.  After further investigation, the crud around the broken off bolt was actually fried coolant, which points to one of the places I was loosing coolant through.

   

Next came the bottom end.  I was greated with a nice sluggy mess, including the oil pump pickup

 

I removed the crank retainers and piston retainers, including bearings to fully disassemble the bottom end.  I did store these in order & they need to go back to the proper cylinder.

 

The pistons are in great shape, although the rings certainly have seen better days.

 

While the engine is apart, I decided to extract the freeze plugs and fully clean the inner water passages of the block.  Glad I did, look at all of the crud in there!

 

Tucked within the bottom of the engine I was able to pull out the PCV filter, which I didn't even realize was in there.  It was fully caked in solid grease which I'm sure prevented it from performing its job.

 

I then degreased the block by hand with the help of biodegradable Simple Green, followed by a full power washing of the interior and exterior. To prevent rust, I then used some Water Displacement spray (WD-40), of which I sourced a full gallon.

 

Next up will be cleaning up all of the other parts from the engine & then rebuilding!

Engine Rebuild: Part 1: Disassembly

After careful consideration, I've decided the next journey to take with making the 240z a reliable vehicle is to fully rebuild the engine.  Main reason is its burning oil (bad valve seals & rings), and I believe the head gasket is blown as its drinking coolant pretty regularly.

I'll be pulling the engine out, rebuilding the bottom end myself and sending the head out to a machine shop to have new seals & seats installed after a pressure test and reconditioning/cleanup.  I do plan to clean up all of the parts, and possibly paint the engine bay while everything is out.

First order of business, hood removal & radiator removal.

 

Next, removal of the intake manifold (and carb's) followed by the removal of the exhaust manifold.  I did break off one of the exhaust manifold studs, but I do plan on replacing all of them, so its no big deal.

 

I've decided that I'll be removing the air galley from the exhaust manifold as its been capped off following the removal of the air pump and other vintage emissions equipment.  I never realized the air tubes were inserted so far into the head.  These will be capped off with screws as the thread on the maifold are still in real good shape.

 

Electrical connection removal comes next.  The most important thing is to label everything & take lots of photos.  In places where multiple wires connected to a single device, I used a yellow zip-tie to identify which wire goes to which connector, thanks to the photos I've taken.

  

I've started to degrease many of the parts as I'll be cleaning them up so they look nice -- not show quality, but clean.  My next major step is pulling the actual engine out & attaching it to my engine stand.

Miata seat speakers

After upgrading my seats to early Miata Seats (Click Here), I finally decided to open up the headrests and install speakers.  The nice thing that Mazda did was they carved out the foam and had it all ready for the speakers to go in, highly recommended for anyone who's swapped seats.  I ended up using some leftover speakers (~2.5 inches) that I was getting ready to donate.  After a bit of fishing wire through the seats and connecting them to the speaker feed in the driver's rear corner of the trunk, I was quite pleased with the results.  As I'm still using the Datsun OEM radio, which is mono, all speakers sound the same, but when wiring I chose to make the connections and wiring an easy switch to stereo if I ever upgrade the head unit.

For anyone looking to but a complete retrofit kit, check this website out -- http://www.3rdstrategy.com/

Here's a great write up from a Triuph guy -- http://tr6.danielsonfamily.org/MiataSpeakers.htm