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Waterpipe Block-off

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2GeNTSi

20+ Year Contributor
1,261
6
Mar 1, 2003
South Sac, California
So first off, I did do some searching and didn't find anything pertaining to my particular question. Everything about the block-off relates to running a air cooled turbo, so here we go.

I just took off my waterpipe today and noticed that I might be able to plug off one of the provisions, but I want to make sure it is safe to do so (it probably is but I just want to make sure).

I'm running a 6-bolt on my 2G and I have a waterpipe that has a smaller diameter pipe running perpendicular towards the firewall. From what I recall, this pipe was for the heater core, and also a tee that supplied coolant to the FIAV. I've been running my FIAV blocked off for sometime now and my heater core failed on me about two years ago. I have since left the feed and return line on the heater core venting.

With that said, the pipe that tees off the waterpipe essentially is just looping coolant back to the thermostat housing. I was thinking I could just cut it, weld it up, then replace the lower nipple on the thermostat with a plug (it's threaded). And lastly cut and jb weld the upper nipple.

To address the coupler issue that prompted me to remove it in the first place, I do have another waterpipe that I might use instead after cleaning it up a bit.

Take a look at the diagram I made (it's ghetto), but this is basically how my waterpipe is setup right now.
 

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I have a 6 bolt with 2g head so I'm forced to use a 2g waterpipe as well. I also eliminated my FIAV and have a non water cooled turbo along with a water cooled OFH. I blocked off 3 water nipples by tapping and putting in a bolt with JB weld.

The 2 that were for the FIAV got tapped with 8x1.25 and threaded in a set screw. The water pipe nipple that fed the turbo was tapped with a 10x1.25 (or 1.50) but it was very close and I was getting worried. If you can use a set screw or shored bolt do so. It was also sealed with JB Weld on the threads and none of my 3 plugs leak.
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I wouldn't use just JB Weld by itself, either weld or plug it.
 

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To make this a ton easier I would suggest picking up a N/A water pipe as it doesn't have the provisions for the turbo water return line nor the water return for the oil cooler (helpful if you have the 90 style oil filter housing which I suggest)

Then I would (and have) cut and weld shut at the red arrow as everything towards the firewall is just the heater core and the yellow is for the fiav which is also iliminated.

Pm if you want to pick one up from me ;)
 

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If you have a 2g head then you have to use the 2g water pipe. If you have a full 6bolt swap with 1g head then the NT water pipe is an option to use.
 
^ +1 depends on which head you are using. I also found a pic of the water pipe mod, however I was using a water cooled turbo so that's still there...
 

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If you have a 2g head then you have to use the 2g water pipe. If you have a full 6bolt swap with 1g head then the NT water pipe is an option to use.

Why? I'm running the 1G water pipe and t.stat housing on my 2G, as I hate how the 2G one is set up. You can't, however, use the 2G stuff on a 1G head as it won't seal without modification to the head.
 
^ +1 depends on which head you are using. I also found a pic of the water pipe mod, however I was using a water cooled turbo so that's still there...

Sorry, I forgot to mention I am running a full 6-bolt swap with a 14B turbo so the NT waterpipe wouldn't work as I need the provision for the turbo.

I was thinking maybe I could use one of the nipples on the backside of the thermostat housing for the turbo instead of the provision running off the waterpipe. The lower nipple on the backside of the thermostat housing would probably be the best choice since it is threaded, and I can use a pushlock setup with a SS line to feed the turbo. However, I'm very new to NPT and AN fittings so I would have to do some research on that.

This also would make it easier in the future if I have to remove the turbo again since that one water line going from the front of the turbo under to the waterpipe prevented me from simply unbolting the turbo. I had to instead remove both the manifold and turbo.

I have a 6 bolt with 2g head so I'm forced to use a 2g waterpipe as well. I also eliminated my FIAV and have a non water cooled turbo along with a water cooled OFH. I blocked off 3 water nipples by tapping and putting in a bolt with JB weld.

The 2 that were for the FIAV got tapped with 8x1.25 and threaded in a set screw. The water pipe nipple that fed the turbo was tapped with a 10x1.25 (or 1.50) but it was very close and I was getting worried. If you can use a set screw or shored bolt do so. It was also sealed with JB Weld on the threads and none of my 3 plugs leak.
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I wouldn't use just JB Weld by itself, either weld or plug it.

Did you plug the two nipples on the thermostat in the same way? For the top nipple I think I would have to cut it because it is not threaded like the one below it.
 

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Raising my own thread from the dead...

Well almost two years later and I'm dealing with the waterpipe again. I ended up having the nipple moved from the old waterpipe that was hacked together and brazed (sp?) and jbwelded to one I got off of craigslist. Well all the vibrations eventually loosened it all up and I have a nice leak coming out of there.

My plan is now to:

1. Remove waterpipe and block off the provision to the turbo, and remove then weld shut the nipple to the OFH.
2. Install a Might Max OFH (front-facing)
3. Block-off ports on thermostat housing (or swap with 1G NT if I can find one)

I did some research and I came to the conclusion that I don't need all the extra hoses (areas that can possibly leak!) and I don't push the car enough to warrant needing coolant running through the 14b. Besides, I have a turbo-timer that I've been bypassing lately, so it will actually be performing its job for a change.

As a little bonus, I'll be able to finally install the oil return line kit I bought sometime ago. I couldn't install if because of the hard coolant line that looped under the turbo to the waterpipe.

EXTREME PSI : Your #1 Source for In Stock Performance Parts
 
A couple weeks back I got everything back on, but while tightening one of the plugs on the thermostat housing, I cracked the housing and it started leaking bad. Good news is the car ran fine with the Mighty Max OFH on.

Fast forward to now and I just got my new OEM thermostat housing back that I had modified by the same weld shop. I had the three nipples removed and welded shut. I also have OEM plugs that I will make sure I don't over-tighten, new outlet neck, rad cap, gasket...hopefully nothing leaks this time around.

I'll be working on it this weekend, so I'll keep my fingers crossed. Probably won't drive it back to Sac since it is still waaay to hot, but I'll probably drive it around town. I haven't driven a manual for more than a month now, and I miss it so bad!
 
If you have a 2g head then you have to use the 2g water pipe. If you have a full 6bolt swap with 1g head then the NT water pipe is an option to use.

Wiseman doesn't know you can use a 1g thermostat housing and 1g pipe on a 2g head? :nono:


Why? I'm running the 1G water pipe and t.stat housing on my 2G, as I hate how the 2G one is set up. You can't, however, use the 2G stuff on a 1G head as it won't seal without modification to the head.

+1 Same setup here.
 
I thought the thermostat housing from a 1G wouldn't fit on a 2G head? Or is that the other way around? I think it has something to do with mounting holes not lining up.

Someone mentioned it above, but also there is a thread on it with pictures somewhere out there.
 
1g thermostat housing and water pipe bolt onto both 1g and 2g heads.

2g 4g63 thermostat housing and water pipe bolts only on a 2g head.

How ever if you make an adapter plate you can run the 2g housing and pipe on a 1g head like I am.
 
Wiseman doesn't know you can use a 1g thermostat housing and 1g pipe on a 2g head? :nono:

Hmmm, no need for that comment. But whatever, everyone makes mistakes.


I was misinformed whenever that post was made. Here is the correct info.

The 1g housing will fit the 2g head, but the 2g housing will not fit the 1g head.
 
Hmmm, no need for that comment. But whatever, everyone makes mistakes.


I was misinformed whenever that post was made. Here is the correct info.

The 1g housing will fit the 2g head, but the 2g housing will not fit the 1g head.

Its all cool man we all learn something everyday, that comment was more of a sarcasm thing no pun intended. :thumb:
 
So I had a chance to swing by home this weekend. I went ahead and threw on the new thermostat housing I modified (no heater or provision for water-cooling). I purchased all of the OEM parts through JNZTuning.

Here are a few few pics I took before I completed assembling it.

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Also had the waterpipe modified. Running the 14B without water-cooling.

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Annnnd what it used to look like before I removed the thermostat housing that had a hairline crack...

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Out with the old:

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Side by side picture. Notice the step-down portion on the mounting surface, I was nervous the coolant would leak past this, so I made sure I filled it with RTV.

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New thermostat housing installed. Drove it around and leak free so far! I don't know if the plugs were supposed to sit flush, but with the sealant on, it was pretty hard to tighten. Plus, I was afraid it would crack again.

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Those are tapered plugs, so they seal good. No need for them to be flush. Either way it looks very professional

Thanks, good to know! It was the first time I've seen that kind of sealant, it flaked off as I threaded it in.

I never though I would miss driving the DSM given all the issues it has had over the years. But it was definitely fun driving it around briefly once I was done working on it. It was down for nearly a month, trying to gather parts and having them modified, then finding a weekend to head home.
 
one thing to consider is by eliminating the fiav and the heater core hoses it can cause pressure issues in the cooling system until the thermostat opens because the coolant pushed by the water pump cant go anywhere.

I did a simple bypass that isnt really noticeable and releases the pressure by allowing the water pump to pull coolant out of the thermostat housing as well as the radiator.

http://www.dsmtuners.com/forums/articles-engine-fuel/441066-how-bypass-thermostat-when-eliminating-heater-core.html
 
That's interesting, I didn't realize that deleting all that would cause any issues. Would this cause premature failing of the waterpump over time if left like this? Also, would a lower temp thermostat help at all? I have a 180 installed.

I've already modified the water-pipe and removed all provisions on it. Also, the OFH oil cooler is gone too. I could always get a 3/8" barb fitting, but then I would have to modify the water-pipe again.

Off topic, I like the cap screws you used on the outlet neck, do you happen to recall the bolt size?
 
cant say for sure it it would kill the water pump but it does put more strain on it since the water cant go anywhere untill the thermostat opens. since the pressure will increase also it will change the cooling capacity and warm up time of the coolant.

the plugs are from home depot. i think they were 3/8 and 1/8 for the smaller holes. issue is stock thermostat holes are bspt so you need to run a npt tap to allow them to fit. it only breaks the edge off the stock threads so it isnt a major retap.
 
Call up jnz and they have the 1/8 plugs from the head that are bspt and fit perfect and then they have the 3/8 plugs from the oil filter housing that are bspt and fit perfect as well.
 
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