JDP6693

iTrader: (1)

Okay, so my '90 vert blew up on me, and this time around I'm taking some precautions with the emissions, fuel and cooling systems I did not have the time, budget or knowledge to do my first time around. It's going well, and should be done by late August if all goes as planned. This post is specifically related to the throttle body though--I'm in the process of rebuilding mine to assure everything moves and operates as it should, being as meticulous as possible (this is the second fc tb I've torn down to rebuild completely) and have run into an interesting discovery that I was stumped on, and feel as if it may be useful information to have when paired with pictures. So here's what I think I've learned:

The cold start thermowax on the back of the tb, once removed, reveals a cutout on the tb itself where coolant flows throughout the tb. (Knew this already.) Following the excellent restoration/rebuild procedure thread SpiritRE posted a while ago, it states to make sure the hole in this passage is open, and free-flowing (clear of all dirt and buildup). Pics 4/5 of the thread, linked https://www.rx7club.com/2nd-generati...-takes-979364/ here, are what I am referring to about the hole, it being open, and the flow of water.

My issue is that on every single throttle body I have in my possession (all of which are S5 n/a, four are manual trans and one is automatic) that hole is apparently welded/cast closed from the factory. I was tremendously confused and a bit unnerved until the very end of his well written thread, when the last post by visatrade mentioned, "I received the new throttlebody today. There are no coolant passages inside the throttlebody on a S5 N/A. You may want to mention that." I assume he's referring to this thermowax hole I'm discussing now, and hope that I'm right. If so, FINALLY something to confirm I'm not losing my mind, at least entirely:

That hole is not present on S5 throttle body thermowax flanges, and that is intentional.

JDP6693

iTrader: (1)

I'll try to lay the pics out to show what I'm talking about below in case this helps anyone else out like it did for me. If I'm mistaken at any point, please for the love of anything in this world correct me.

Also a question I came to ask (aside from hopefully trying to catalog my frustrations to ease someone else's in the future) and would love input on, is that the thermowax gasket and mating surface itself is different on one of the tb's, third one in the pic set, it has no hole on the backside for the coolant to flow, and a solid gasket with two locating pins on it, compared to a hole for coolant to flow, and a gasket with holes for the location of the pins that are on the thermowax itself. Anyone got any ideas about that?

The tb from my old motor, '90 S5 m/t. Ignore the poor paint lines, it's nowhere near done yet.


Throttle body from the new (to me) motor. '89 S5 vert, m/t.


Donor parts tb, ebay score from (supposedly) a '91 S5, m/t and in rough shape mostly. This is the one with the odd gasket and lack of holes on backside of thermowax itself, also pictured below.







The first tb I rebuilt, off a '90 S5 automatic coupe and mostly for example of what goes where regarding springs, to use in conjunction with the +90 pics of disassembly and the printed binder-style fsm I have for reference (sweet *** graduation gift).



The thermowax from my motor, broken gasket and all.


Side-by-side of all four thermowax valves.

JDP6693

iTrader: (1)

At the end of it all, I'm likely going to restore the thermowax system so that it works properly, as well as the double-throttle system, since I've read vastly more hate posts about "the TB mod" than I have good things about it.

Thanks for reading, sorry for the wall of a post, but hopefully it was entertaining at least!!! Like I said, if anything is wrong that I've listed, please correct me. I just hope I'm not unlucky enough to have stumbled upon four throttle bodies ALL with the thermowax still there, and the holes closed after the factory. That'd be some serious s*** luck.



Also- bonus shots of the printed FSM I mentioned earlier. Love this thing, and it stays far away from the garage where the humidity and car stuff can get onto it, I use my computer and the online fsm out there. May not be as cool to you guys as it is to me, but eh. Here it is anyway.
[IMG]https://cimg8.ibsrv.net/gimg/www.rx7club.com-vbulletin/1632x1224/80-img_3062_a4e9cda2f6ebde157724bd96544f236271b16a8b. jpg[/IMG







Footnote: For some reason, the first post didn't include all the information I had originally typed, luckily I'd copied it and pasted it to a word document for exactly that reason. Sorry for the multi-posts and huge *** pictures!!!