Z24E (slow but steady build)

[frankendat]

Quick point: There are a number of sound reasons against building a Z24, or any decades old motor, but that ship has sailed. The build is moving forward.

 

Some of the used parts acquired, for this conversion attempt, come from a 30 year old KA24E, other parts come from a 35 year old Z24. The parts are dirty, oily, and covered with a layer of fine black soot that gets everywhere and is hard to abate. 

 

Since I will be coating the engine and internals with ceramic performance coatings, parts must be clean. I was tempted to media blast them as-is, but am budget conscious and last time I blasted an oily part, the media had to be discarded, the blast cabinet, hoses and gun throughly cleaned. 

 

The majority grease and oil came off easily, after an overnight gasoline soak, and a dish soap scrub. There are a number of bolts and sensors on the manifolds and plenum. it took two evenings of penetrating oil soak and home style impact driver (I hold the wrench on the nut and Dad hits it with a hammer) to get some of the plenum bolts.

 

Today, I started with brushing on phosphoric acid on the manifold, diluted 1 to 3 with water, without good results. I considered attempting full strength, but worry about etching the parts. So, I used acetone, wire brush and rags, to go over the manifold, then I put it in the oven for 1 hour at 200 degrees. Once the manifold cooled, I wiped it again with acetone and put it back in the over for 2 hours at 200 degrees.

 

It is late, next step will be a final acetone wipe and media blast. For those who are curious, the reasoning behind the heat ups, and cool downs is attempt to draw out any oils in the metal. Oils play hell on ceramic coatings

 

 

[frankendat]

I went through too many steps, in this process. Played it safe and took far too much time. Media blast removed 99% of the carbon deposits. It would be 100%, but the glass in the cabinet is scratched and it is hard to see fine details. Fun fact, to prep this for coating, all threaded holes must be plugged. There are 48 plugs of varying size needed to fill the manifold. It was nice handling the manifold, without getting black soot, on gloves, on clothes on me. Since I haven't encountered this carbon soot stuff on other engines, my theory is that it is a by product of the pollution controls on the Z24 and KA24E.

[wayno]

A good thing to do in blast cabinets is put plastic wrap on the glass on the inside, about 5 to ten layers being careful to not have any air bubbles, that stuff is clear so it's almost like it is not even there, then every time it starts getting hard to see remove one layer and it is clear again.

[frankendat]

Good call Wayno, I'll give that a shot, when I get new glass.

[frankendat]

23 hours ago, wayno said:

A good thing to do in blast cabinets is put plastic wrap on the glass on the inside, about 5 to ten layers being careful to not have any air bubbles, that stuff is clear so it's almost like it is not even there, then every time it starts getting hard to see remove one layer and it is clear again.

What kind of plastic wrap? The kind used for sandwiches? I have been checking it out and the saran wrap (sp?) and it looks flimsy.

[frankendat]

The intake turned out decent. For the plenum, II only performed one preheat and did not use dish soap to wash (It seems the dish soap was leaving the film I kept acetoning off. I still used acetone before coating. The pre coating process was still effective and took about half the time. The heat dissipating coating is only offered in one color.

 

 

 

Edited July 12, 2020 by frankendat
forgot something

[datzenmike]

Are you coating? What about how the KA injectors? and how they will be fitted to the intake?

 

The 4 holes on the underside 3 small one larger... was there a bolt on manifold covering and joining them?

[frankendat]

43 minutes ago, datzenmike said:

Are you coating? What about how the KA injectors? and how they will be fitted to the intake?

 

The 4 holes on the underside 3 small one larger... was there a bolt on manifold covering and joining them?

Good day datzenmike, the last two pics (against the red background) are coated parts. The color is close to the original aluminum, but the ceramic coating claims to transfer heat away. I removed most of the bolts and sensors, because of the heat required before the coating is applied. This particular coating can be air dried. Next steps are cleaning and coating the throttle body, top of the head, fuel rail, and top of the valve cover, then swap products and do the combustion chamber. I am a little concerned abut the Thottle body, because if I disassemble it to coat, I want to make sure I can assemble it.

 

I like the ceramic coatings and believe they work as advertised, but if I didn't have a place to do it, then with my budget, I would probably skip it. All and all it is a good excuse to deep clean the engine.

[wayno]

On 7/11/2020 at 7:47 PM, frankendat said:

What kind of plastic wrap? The kind used for sandwiches? I have been checking it out and the saran wrap (sp?) and it looks flimsy.

It's just plastic wrap, it is the stuff that easily sticks to itself, I made a blast cabinet and put about 8/10 layers on the inside glass, it stuck to the layer below it without any other products, I would blast for a while till I could not see, lift the top and peal off a layer and continue blasting till I could not see again, it was a very long time ago so I don't recall much about it anymore except it was a plastic wrap which was very thin, likely used to wrap food normally, maybe sandwiches.

[frankendat]

23 hours ago, wayno said:

It's just plastic wrap, it is the stuff that easily sticks to itself, I made a blast cabinet and put about 8/10 layers on the inside glass, it stuck to the layer below it without any other products, I would blast for a while till I could not see, lift the top and peal off a layer and continue blasting till I could not see again, it was a very long time ago so I don't recall much about it anymore except it was a plastic wrap which was very thin, likely used to wrap food normally, maybe sandwiches.

Excellent, I will give it a try

[frankendat]

The coating continues.... the valve cover. As I am sure all of you know, there are two stickers on the valve cover, one Nissan and one with some spark plug info. I used a heat gun and a razor to remove. After the bulk was removed I went over the area with the three products picture below. The cover looked clean, but after spraying, li

ttle  balls of bullshit, popped up. I cussed it, media blasted it and tried again, used the same three cleaners, had the same problem. The finished valve cover in the last picture, still has a small "balls" patch, but it's good enough for the girls I know. I think a factory Nissan sticker would contrast well and cover the bad spot, since now I know their adhesive is damn resilient. 

[frankendat]

Pictures got a wonky in that last post. Anyway performed some backyard science testing on the performance coating: With the valve cover media blasted and clean, I used an infra red heat temperature gun and the temp of the valve cover was 83 degrees. 

I placed the valve cover in the oven at 275 degrees for 10 minutes, removed the valve cover and checked temp 224 degrees. Waited 10 minutes checked temp again 135 degrees. 

The next day, after coating, the temp of the valve cover, sitting on the bench was 80 degrees; after 10 minutes in the oven at 275 degrees, valve cover temp was 230 degrees; 10 minutes later the valve cover temp was 109 degrees.

The heat dissipation without coating was 89 degrees in 10 min.

The heat dissipation with coating was 121 degrees in 10 min.

According to my uncertified backyard test, the coated parts dissipate heat approx 25% faster with the Cerakote heat transfer coating. (if my math is right) 

[frankendat]

 

It has been a time suck, the last couple days. Plugging all the holes with either high temp tape or a cork,  takes time. Coated the perimeter of the head with heat transfer and added today combustion chamber coated with heat retention coating (like the heat transfer, the heat retention is only offered in one color.) the heat retention coating will also be applied to the top of the pistons and the bottom of the valves.

[datzenmike]

That head... looks familiar somehow.

 

Isn't this coating like a ceramic and reflects heat. Like shuttle tiles. Less heat absorbed the more is available for expansion and pushing on the pistons.

[frankendat]

23 minutes ago, datzenmike said:

hat head... looks familiar somehow.

 

Isn't this coating like a ceramic and reflects heat. Like shuttle tiles. Less heat absorbed the more is available for expansion and pushing on the pistons.

 

You might be noticing the exceptional work a skilled craftsman performed on the head.

 

Yes, the reddish coating keeps heat in (shuttle tiles) and the gray coating forces heat out. I have a third coating that reduces friction that will be applied to some of the internals. 

[Spiff]

I'll say the performance of a fuel injected z24 is a good reason to build it. Are you bumping up the compression any? I think flat top ka pistons are the way to go. 

What engine management system are you using? 

[frankendat]

Howdy, I went down the rabbit hole on the pistons. The flat top KA24E pistons are an excellent choice and I may regret not going that route. I purchased Mazda/Mitsubishi pistons that require  91.1mm and raise the compression into the 10's. The pistons require some modification to work. I have been trying to run down the 3 (known) people who have built with this combination, but they have been unresponsive. I  will work it out, but takes more time.

 

As far as engine management, I like the Ford EDIS with Megajolt, but there is much work to be done before that decision is necessary

[Spiff]

Haven't heard about fitting Mazda pistons before, I'm using forged ka pistons but with a 8.5:1 compression since I'm turbocharged. But I think with the flat top ka pistons you'll be in the 9 or 10:1 range. Regardless, it makes good power.  I'm running a maxxecu, ran a megasquirt before that