Whats up guys.
So I'm in the process of putting back together my motor and I stumbled upon a few questions.. Now I'm not a pro with RX-7s so these might seem like silly questions, but cut me a break. I provided pictures to cure any confusion.
First question is regarding the Oil Inlet pipe. Shown in the picture. Now I don't know if this hose was rubber at some point or not but mine is hard plastic right now. And I'm concerned about the part where it connects to the metal oil line (which I circled in red) I can rotate this hose and slide it on and off fairly easily. Is this normal? I feel like oil would be leaking through, although it wasn't leaking before I pulled the engine. Is this okay?

Second Question: I'm doing the vacuum hose replacement while I'm at it and had a few questions. I bought a ton of hoses like recommended on the forum, 40ft 3.5mm, 16ft of 6mm, and 5ft of 8mm. Where are there even 6mm hoses to be replaced?.. all i see is those 4mm lines basically...
Picture labeled #1.
Circled in RED: Are these bigger hoses also vacuum hoses? Are these the 8mm hoses that need to be replaced?
Circled in YELLOW: Are these SUPPOSED to be plastic? or do they need to be replaced to silicone? Those 2 lines are dif material than the rest of these hoses and are real hard plastic.. do these get replaced too?
Circled in GREEN: This hose is also really hard, but doesn't seem brittle. Seems like a different type of hose.. Do I replace this hose with the valve on it or let it be?
Picture #2.
What is the reason for the S-Curve? When replacing this hose do I need to cut the same length? and how will I make the S-Curve from straight silicone hose? or is that how it sits in the engine and the s shape will be created?...
Um, yeah... so these are the questions.
Please help me out. My apologies if these are some easy *** questions..

If I have any more questions I will submit them in this post rather than make a new thread.

 

OK, some good questions here.

First off, the hose going to the oil fill neck - it was once, a LONG time ago, nice soft rubber. It has vulcanized over time and is pretty much done. You can replace that with silicone, if it's GOOD silicone it will be OK. But, silicone over time will break down from the oil vapors and get mushy. Viton hose is the "right" hose for the job but is pricey and harder to find. You can run silicone for a LONG time with no problems. here.

The "plastic" vacuum lines may have been replaced in the past with another rubber hose that also vulcanized. They are NOT supposed to look like that. Since you have the car apart, go ahead and replace them with silicone. Pro tip - get a candle lighter and heat the ends with the flame for a few seconds, that makes the hoses soft again so you can actually remove them without breaking the plastic solenoids they're attached to.

ALL those 3.5mm hoses can be replaced with silicone no prob.

The left hose circled in red is a coolant hose. That should be replaced with a new Mazda coolant hose, end of story. Don't use silicone there, it's not reinforced to deal with the pressure of the coolant system and it WILL fail on you.

The hose on the right circled in red is a fuel line - use the stock fuel lines. Mazda did a good job on the stock rubber fuel hoses, if yours are shot, call up Ray at Malloy and get a fuel line recall kit. It comes with all the rubber fuel lines in a pack along with a bunch of other stuff. The stock fuel line is a metric size so it fits just right, it's temperature resistant, and it lasts for a long time. Use the stock spring clamps too.

That S-curve on that one vacuum line is just to go around the throttle body to the metal hardline it attaches to. A silicone line will generally go to the same shape as you route it - if you bought good thick-wall silicone, it will fit good and won't kink. Cut it to the same length as that hose.

And, I really hope you have some of my Viton check valves to replace those stockers. If not, PM me and I'll get you set up .

Dale

 

Hey Dale. Thanks very much for answering all of this. Helped me a bunch.
Yeah since I'm trying to get this put back together fast, I will just use the silicone hose. Is the 8mm okay here?

Should the coolant hose really be replaced or will it hold up for a long time still? Can't I just get some same diameter coolant hose from say Autozone or something? Yeah, I figured those were coolant lines but I didn't think that a coolant line also ran thru the rats nest.

And no I actually don't have the check valves. Had no idea that new ones are needed. Why are new ones needed anyways? I don't remember reading about getting new ones.

Anything else really important that I should switch out now before putting back the engine together?
I read on Rob Robinett's site that the two vacuum hose restrictors need to be changed out but I don't know much else about it and never heard anybody else mention this.

Thanks much, Roman.

 

And where are the 8mm hoses that need to be replaced with silicone? I bought 5ft like it said on here but i don't see where it would go..