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

Headlight wiring harness with relays

After reading horror stories about the headlight/wiper combo switch melting due to the full amperage of the headlight beams going through the switch, I decided to install a wiring harness with a set of relays.  MSA sells a great plug-and-play unit which is built by an avid Datsun Electrician, although I decided to save some money and build my own.  At the end, I invested about $40 and have much better low and high beam headlights, and will save the combo switch.

I started off with a cheapo pre-made relay wiring harness which I acquired from Amazon for pretty cheap (Amico Car 30A Fuse 2 H4 HID Headlight) and a set of harness plugs and some wire/shrink wrap.

 

I next needed to extend the wiring harness and include the correct harness plugs to allow me to plug directly into the Datsun wiring harness as a feeder and then into the headlights directly.

 

Then it was as simple as unplugging the existing headlights and plugging in my new harness, including connecting it to the battery to power the relays.

As reference, here's the best diagram/explanation I can find.  Thanks go out to the original author.

Door weather seals

After 42+ years of service, I decided it was time to seal up the doors better so if I get caught out in the rain I wouldn't be sitting in water.  What was left of the old seals was quite a mess

   

When I purchased the car, I was excited because it came with what appeared to be a full set of rubber weather seals for the doors, hatch, etc.  The seals that came with the car were made for the 240z, although as many have experienced they were from a company called Precision, the doors would not close, even with a hip slam.  And it was more than adjusting the door striker plate would resolve.  Luckily I did not glue these in place so they came off very easily.

Upon further investigation, I decided to look for other vehicle weather seals that would fit the 240z.  The best option would have been an early 2000's Kia Sportage, which my local junk yard (Victory Auto Wreckers) said they had.  After a pilgrimage to Victory on my way home from work one day I was unable to find the Sportage.  I did however start looking at all of the other cars that they had.  The next best option appeared to be a late 90's POS Chevy Cavilier.

After removing and then finally cleaning up the weather seals, I was quite happy with what I had obtained for $5.00

 

Once installed (without glue for the first try), I found that I needed to cut about 8" off and then bend the straight seal around the 90 degree corner of the 240z's door.   I do plan to glue these in place eventually, but the wealting appears to hold it on very well.

   

Throttle Jerk Fix

So my 42 year old car has always had a very jerky accelerator pedal, which is a common issue for early Datsun Z-Cars with the mechanical linkage.  After looking at my options, I decided to change over to a throttle cable (similar to modern cars) which should deliver a silky smooth pedal and acceleration.

First, I decided on a Mr. Gasket steel braided throttle cable kit from Amazon for  (#5657)  and an aluminum throttle arm from Speedway Motors for (## 91018400)

In addition, I needed to figure out a way to hold the cable housing at the carburetor.  For this I chose a hardened L bracket that I had laying around & mounted it to the exhaust manifold heat shield.  As there's not much pressure being put on this, it should hold up well.

 

I next had to modify the accelerator pedal, including bending it & then determining the best way to mount the cable end.  I chose to not drill it, rather use an "S" connector.  Longer term I may drill it out, but for now this works.

 

I think needed to hook everything up and adjust for the proper amount of slack.  I also greased the cable very well, although it probably could use some more.  Please note that I did change the L bracket that was used as I needed it to be in a better position over the carburetor linkage.  

 

Overall, I'm very satisfied with the outcome.  I'm now able to accelerate from a stop very smoothly!  The only downside that I've identified thus far is that I needed to replumb the breather from the valve cover as the throttle arm blocks the path of the original hose.  I also need to change the color of the linkage arm as they sent me a purple one...probably some sandpaper and it'll brush right off.

Here's some additional info that I've run across throughout my travels: