air bleed with plenum coolant bypass
 

I am planning to put on some SAMCO hoses and bypass my plenum coolant as outlined in the April 2007 Heart of the Beast article. I saw a few pictures where it appears others have bypassed the plenum coolant without air bleed hoses as shown in the write up. I like the cleaner look of no top end plumbing, but I am far more concerned about functionality than looks.

Any thoughts on the bleed hoses?

Any advice in general for the job. This is my first attempt at doing anything to the Z, so I am excited and nervous at the same time. I have a 1995 factory service manual from a previous vette, is it worth ordering the 1991 specific manual and the LT5 supplement before I start or is the 1995 manual close enough for this job?

Re: air bleed with plenum coolant bypass
 

I'd suggest having the 91 manual. There were changes throughout the years.

Re: air bleed with plenum coolant bypass
 

Hi Brent,

Give us some more details on your car, colors and number. How many miles and we may be able to help more.

Also check out the following websites for some good tech articles and
reference material before you start.

http://pnwzr1.net Enter the site and on the left find the tech section
www.zr1specialist.com

Do get a service manual for the year you are working on though.

Oh yeah, we like pictures too.

Welcome

Re: air bleed with plenum coolant bypass
 

I plugged my injector housings and removed all the coolant tubing from the plenum but was concerned about air pockets forming (Mark H had some issues with this). I drilled and tapped fittings on the back side of the injector housing and ran the hosing under the plenum and back to the recovery tank. Here's some pics of the finished product.
Rich

Re: air bleed with plenum coolant bypass
 

Rich, that is pretty interesting for the coolant.. I assume it is working out fine.. no air pocket issues

Re: air bleed with plenum coolant bypass
 

My car is black with gray interior and #1164, with ~118K on the clock. Has some port work (Corey Henderson), OBX headers, Borla exhaust and 4:10 gears. It had a small coolant leak from the Tee on the plenum on the passenger side. I removed and epoxied the Tee, but it still leaks, so I figured I'd try the coolant reroute and get rid of the possibility of a leak.

Thanks to everyone for the input, I'll check out all the links and try to post some pics tonight. I am still waiting for my gasket set from Jerry's so I have some more time to read up before I get started, hopefully this weekend!

Re: air bleed with plenum coolant bypass
 

It worked out great, all the air blead out fine, no air pockets. I was concerned because the installed fittings are not at the highest point in the injector housing, but no air pockets. I kept a close watch after start up checking for any hot spots.
Rich

Re: TB Coolant Elimination Completely with NO Air Bleed
 

Opps. Yeah, I mixed that up. You need to check the temp gauge and do a feel test on the coolant tubes and crossover pipe to ensure water is flowing thru them. Marc told me he discovered the air pocket when he saw his temp guage going up but the lower portion of the coolant tubes and the crossover pipe were stone cold, so he shut down the engine.

Rich

Re: air bleed with plenum coolant bypass
 

As gorgeous as that engine looks in the pictures above, it looks even better in person! It is simply AWESOME!

Re: air bleed with plenum coolant bypass
 

Thanks Paul.....it may be all coming off if I can't pass emissions in Nov....We'll see.

Rich

Re: air bleed with plenum coolant bypass
 

Boy I hear you there Rich. That's why i sold everything and went back stock. Well almost anyway. Passed with flying colors here in Idaho even with the Flowmaster Cat-Back.

Re: air bleed with plenum coolant bypass
 

Ada and Canyon (where I live) Counties in Southwest Idaho require smog checks biannually. DEQ Nazis wouldn't give me a waiver for the air injection system and it was just going to cost much to retrofit everything for the AI and cats. Even then no guarantee I would pass, that's why I removed the headers and chip. Now I have Marc's piggyback chip in so I can remove it easily and just have the stock chip in for smog.

Re: air bleed with plenum coolant bypass
 

Well in PA, if you get Classic tags (15 years or older), an emissions test is not required. Another benefit is once you pay the $142, it's good for life, never have to register again. Just get it inspected once a year. The downside is your only suppose to drive the car once a week (no way anyone would know that but you) and the tags are purple.

Re: air bleed with plenum coolant bypass
 

I have the plenum, injectors and the driver's side injectors housings off and had a few quick questions.


1. When I pulled the injectors off the passengers side I noticed every other injector had two o-rings on it and all but one of these also had a blue plastic cap. I presume the other blue plastic cap is in the injector housing, but I haven't fished it out yet. Does this mean I have a bad injector or can I just replace the cap assuming I can find it once I get the other injector out? I believe they are relatively new (<1yr) FIC injectors if that makes a difference.

http://www.zr1.net/forum/picture.php...pictureid=1377

2. The gaskets I pulled off were cut to match the porting, so I plan to cut my new ones similarly. I also had to scrape off a ton of permatex from the existing gaskets. Is it advisable use permatex when putting the new plenum, IH housing and IH coolant tube gaskets on?

http://www.zr1.net/forum/picture.php...pictureid=1378

Note: I also noticed that the gasket was incorrectly installed on the passengers side blocking off the hole to the IH coolant pipes.

Other than this everything is going OK - thanks to all the pointers I've received from the experts!

Re: air bleed with plenum coolant bypass
 

I have done several injector replacements and I have never see injectors with 2 O rings on any of the injectors, primary or secondary. Also, those blue caps are put on when the injectors were shipped, I believe they should have been removed before installation. I went with the FIC stainless injectors and they have performed flawlessly.

I did not use any permetex on my gaskets, the gasket should seal fine by itself. If you ever need to put the plenum in the future, it will make plenum removal easier and no need to replace the gasket.

Rich

Re: air bleed with plenum coolant bypass
 

I was kind of afraid someone was going to say that about the plastic caps :).

I didn't find the "missing" cap in the injector housing or on top of the intake valve, so I assume it was never put on in the first place or it fell off and was vaporized at some point. The previous owner swapped out the injectors right before I bought it, so I presume he just neglected to take off the caps. Hmm wonder how the injectors even worked????

Re: IH and Injector Installation
 

I found the picture below of my injectors at FICs website with the blue plastic caps and double O-rings. Just to be safe I emailed FIC to get their input. I'll update the thread once I hear form them.

http://www.zr1.net/forum/picture.php...pictureid=1379

Re: air bleed with plenum coolant bypass
 

I spoke with the techs at FIC. The blue caps on the tip of my injectors are called "Pintle Caps". Their only purpose is to allow you to remove the injector without dropping the O-rings in the manifold. They are going to send me a few at no charge and I should be able to pop it on without much effort. They said I could put it back together as is without the cap, but since it's apart anyway might as well put them back on.

Re: air bleed with plenum coolant bypass
 

That's 'cause you got RC's, you rich *******. :bootyshak

Re: air bleed with plenum coolant bypass
 

They are sending me a few new Pintle Caps ( I only need 1, but it won't hurt to have a spare) that I should be able to pop on, then reinstall the injector. The purpose of the pintle cap is to retain the 2 O-rings on the secondary injector when you remove the injector from the injector housing. You do in fact install the injectors with these blue caps on. It is worth noting that these caps do not cover the injector O-ring, just the very end of the injector. They do not interfere with the operation of the injector.

Hopefully that clears it up, if not let me know. I wanted to make sure it was captured for the sake of posterity (AKA the next poor sucker that has the same question :) )

Re: air bleed with plenum coolant bypass
 

I have all my parts ready to go back in and I'm off all day tomorrow! Anyone have the torque values and sequence for the injector housing bolts and coolant pipe bolts? I found the info for the plenum, but can't seem to find the injector housing info in my service manual or on line.

Re: air bleed with plenum coolant bypass
 

Got it all put back together and it runs great with no leaks. I took a few pictures (not very good ones) below. Wanted to say thanks to everyone for all the help! Couldn't have done it without it!

http://www.zr1.net/forum/picture.php...pictureid=1447

http://www.zr1.net/forum/picture.php...pictureid=1437

Re: air bleed with plenum coolant bypass
 

I may be wrong, but it appears to me that the crossover hose set is only brought up to circulate hot water around the throttle body. THAT I bypassed when I bought the car new. I just ran a rubber hose under the plenum to connect back to the tank. I like the look of plugging the water ports. It looks to me that the large coolant return tubes carry coolant back to the upper radiator hoses from the same place as the TB heating hoses. There would be no air pocket as the main returns are located in the same place. I would rather cool down the plenum and ram tubes as much as possible.

Re: air bleed with plenum coolant bypass
 

I had bypassed the coolant from around the throttle body on mine back in 1990, as I had done on both my 1985 and 1989 cars. I actually showed that trick to Guldstrand when he was at my shop in 1985.
I DO like, since I'm not using hot coolant around the throttle blades, to eliminate that hose system that returns back to the overflow system. I will be powdercoated the entire top side of the engine in Silver miniflake soon. It seems to me that with the water returns just under the plenum, that there could not be any air trapped there.
IF there was an inch of trapped air in the plenum ports, all the better. I don't want any added heat into the plenum.