87ROCZ

iTrader: (3)

Hi guys/gals... I have a Edelbrock 3817 Vortec lower intake and from the documentation it isn't clear on what I need to do with the coolant by-pass issue. I know that my Vortec heads do not have the internal coolant bypass as did the older heads and I should bypass the coolant to the water pump from the intake.

My question is how? My stock water pump has a spare inlet that has a bung in it now that, when removed, is basically an open port to the water pump.... do I just plumb in two new fittings (one on the Edelbrock intake and one on the water pump) and connect a rubber hose between the two? Is that the correct thing to do? The install sheet that came with the base doesn't really say what to do, all it says is this..

"NOTE: On 1990 & later engines,only two of the three pipe threaded holes on the front of thebaseplate are used. Plug the extra hole with on of the supplied pipe plugs."

Well that's great advise if I had a 1990 or newer engine but mine is a 87 engine so what should I do? There are 4 threaded holes in the front of the intake.... one is for the heater core hose, one is for the coolant temp sensor, one is for that other square temp sensor, so I am assuming the 4th would be where this coolant by-pass would go either that or be blocked off, and would it go into the hole directly below the thermostat opening?

Anyone with pics or advice that can help would really be appreciated!

Thanks!

Stan

vetteoz

iTrader: (13)

GMPP Ramjet has Vortec heads

GM instructions:

"The RAMJET 350 engine includes a standard rotation water pump. This is a cast iron, long leg water pump; the same pump that is installed on the GM Performance Parts ZZ4 crate engine.
Any small block engine, regardless of year, that uses Vortec heads,
will require an external coolant bypass line from the intake manifold to the 5/8" hose nipple on the water pump (passenger’s side).
Suggested routing is from the 3/8" boss on intake manifold to the water pump."

LilSki

iTrader: (1)

I think you are confusing coolant bypass with exhaust crossover. Vortecs do not have an exhaust crossover so in order for EGR to work properly in a 3rd gen you would need to plum exhaust gases to the rear port of the intake near the distributor.

As for the coolant crossover is works the same as your old intake. It just has an extra hole near the fuel rail so you plug it. Other wise connect everything else exactly like you had it on the old intake.

87ROCZ

iTrader: (3)

Ok... so now I am confused.... block the hole or connect it to the water pump..

BTW: I am not using my EGR (programmed out of my prom) so I will be blocking those holes off with the suppplied plate

vetteoz

iTrader: (13)

No he is not

Wrong

Vortec engines don't have a coolant bypass built into them like the older small blocks.
The reg SBC block had a hole in the pass side of the water pump that routed water through the head to allow water to circulate when the thermostat is closed to prevent hot spots forming.
Vortec blocks and Vortec heads don't have those holes and some sort of bypass is necessary.
Note the GM install instructions for Vortec heads I posted above

A comment from another site
drilled 5 - 1/8" holes in the thermostat. That was not enough bypass for my Vortec heads
I had to run two temperature gauges with one sender in the head and the other in the manifold to verify this.
In my test, before the thermostat opened, I had as much as a 45 degree difference between the two gauges.
When my gauge in the head was reading 140, my gauge in the manifold was 185. Once the thermostat opened, the gauges would sync.
So, my determination is a bypass hose MUST be installed with a Vortec engine.
If anyone doubts me on this, run the test yourself.
However, there would be no way to do it without the use of 2 temperature gauges.

LilSki

iTrader: (1)

EDIT: I apologize as I apparently misunderstood. It seems I basically accomplished this bypass by using the heater core.

On my car which is running a 98 vortec block has one heater core hose connected to the intake via one of those front holes. And the return goes into the top water pump hole.

vetteoz

iTrader: (13)

Follow the GMPP instructions I posted

In any case a quick Google search will bring up exactly the same info as what I have posted

87ROCZ

iTrader: (3)

Thanks vetteoz .... I will use that advice.... so I guess I just use the hole under the thermostat to plumb to the water pump...right?

LilSki

iTrader: (1)

My only problem with the hole they provide is that is it ends up right behind the bracket for the fuel rail. Making it impossible to put any kind of nipple on it without modifying the fuel rail bracket in some fashion. Not saying you can't do it but just be sure to mock up the fuel rail in position before you make any final decisions.

87ROCZ

iTrader: (3)

Good advice... I will definitely size that up as well...

vetteoz

iTrader: (13)

Is it possible to relocate one of the sensors to there so as to free up a hole in a better location?

LilSki

iTrader: (1)

Maybe you could. but just so you can get an idea this is a pic of the extra hole when installed.



As you can see I installed a plug but look how little room there is even with the plug. I doubt you could get a sensor in there either. With my car I only use two holes out of the 4. I use one for coolant sensor and one for the heater hose connection. BUT I run a megasquirt so I don't require the extra sensor for the 9th injector.

87ROCZ

iTrader: (3)

Yup...you're right... I just popped on my fuel rail and I can definitely see what you are talking about... no way to get a nipple fitting in there for sure and I doubt either of the two sensors will fit in there as is....

Now... I am not running the 9th cold start injector... it's been programmed out of my ECM and although it's still connected to my fuel rail (never got around to properly blocking it off) it is definitely disabled..

Could I just remove that square coolant sensor altogether and plumb a fitting in it's hole, then just plug off the one under the thermostat/ fuel rail?

87ROCZ

iTrader: (3)

Hold on... according to my shop manual this coolant switch isn't connected to the PCM at all... it's basically a relay with the coil side being energized when the car is in crank mode, the other side is a bi-metal switch which is tied to the ground leg of the cold start injector circuit. I think that if I disconnected the conector to this coolant switch/relay it wouldn't make any difference at all since my cold start valve is not operational anyway? A disconnected connector would basically disable the cold start injector.

Or would this throw a code or something like that?

LilSki

iTrader: (1)

I doubt it would throw a code since you have it programmed out of your ECM. I would plug the one hole like I did and ditch the 9th injector sender and route that hole to the water pump.

Tuned Performance

iTrader: (92)

the 9th injector is in no way hooked up too the ecm acc power goes to the cold start switch then onto the ninth injector. Since this was programed out more than likely you are using $6e definition. You can fix the long cranking time the $6e programing has it expects too see 8 drp before cold start injector pulses are sent.

87ROCZ

iTrader: (3)

Cool... then this is what I am going to do.. the less things plugged in the better, I hate clutter under the hood!

As for the Bin....I had my car dyno tuned a few years ago and the Programmer dude basically programmed me a new Memcal for the best performance and while at it I told him to program out the 9th cold start injector and the EGR valve. He did compensate for the start up fuel demand by tweaking the fuel tables (I guess that's what you call them, I'm not up on the PCM program lingo)

Tuned Performance

iTrader: (92)

$32B would be crank pulse width vs coolant temp.

87ROCZ

iTrader: (3)

I ended up putting a bung in that really tight fitting hole and fabricated a fitting for the other hole that the cold start sensor/switch was in... so I should be good now... the water pump I am using is one that came off of a 88 GTA and thinking about it now, it's kind of weird that the pump had that extra hole in the top of the pump, the one that was originally on my 87 IROC did not have the hole.... but I guess it will work out OK...

Tuned Performance

iTrader: (92)

the pump must have been a reman one, the 87-92 c and k chevy trucks had the fitting npt hole in the pump

vetteoz

iTrader: (13)

Brilliant design work from Edlebrock.
They make these for TPI's ; the vast majority are going to be 3rd gens with the fuel lines crossing to the drv side
( not straight out like Vettes ) and then position the hole so you can't use it

87ROCZ

iTrader: (3)

Cool... lucky break for me then, I have a buddy that uses a water pump off a 4.3L Vortec engine on his 1970 350 block with Vortec heads but his pump has two fittings on it and he uses both, one goes back to his heater core and the other is a short hose into his lower intake. He is running an Edelbrock performer intake and carb...

87ROCZ

iTrader: (3)

I thought the same thing!!! Someone obviously didn't actually sit a 3rd Gen fuel rail on top of it that's for sure!

vetteoz

iTrader: (13)

Worst case , one could always T the bypass hose into the heater return line anywhere that suits / fits if having a waterpump with only one port

LilSki

iTrader: (1)

Hey 87ROCZ are you running the heater diverter valve that stops flow to the heater core when you're not using heat?

If you are not why don't you just hook it up like I did mine and use the heater core as the bypass?

EDIT: here is a picture how I set mine up. I used a 90 deg out of the intake and returned right to the water pump.

87ROCZ

iTrader: (3)

Hey.... I made a quick sketch on what my coolant routing was before I put on the Vortec heads (this was how it was stock, or at least when I bought the car 11 years ago) and added that dotted line to indicate what I plan to do for the coolant by-pass, basically a coolant hose between the base of the intake and that extra top hole in my water pump.

Can you guys have a look and tell me if what I have is correct and will work

LilSki

iTrader: (1)

As long as your heater core circulates all the time leave it as is and you shouldn't need the added bypass. The only point of the bypass is to circulate some coolant when the thermostat is closed. And as long as you heater core circulates all the time it will serve that purpose even though it is returning to the radiator and not the water pump.

BUT if you still have the factory heater valve that stops flow to the heater core unless heat is called for then you would need to add the bypass.

EDIT: This is the valve I am talking about.

87ROCZ

iTrader: (3)

Hey ... nope I definitely don't have that valve, my hose goes from the firewall (heater core) straight to the lower intake, it used to go through the throttle body but I by-passed that years ago..

Soooo... I guess I don't need to run the by-pass to the water pump after all?

But I am sort of wondering how the coolant will by-pass through the heater core if the thermostat is closed?? From how I see it and following the path of the coolant to the heater core.....

1. Water pump pulls coolant from the drivers side of the block
2. Pushes the water to the lower passenger side of the rad.
3. Up and through the rad and out the top side on the drivers side of the rad
4. Into the thermostat in the intake
5. Leaves the intake (if the thermostat is opened) and goes into the heater core
6. Comes out of the heater core and into the upper port on the passenger side of the rad.

So if I am looking at this right, with the t-stat closed the coolant stops, with the L98 heads there is a passage through them to let a small amount of coolant to flow... but with the Vortec's there isn't....

Unless I am not looking at this correctly or assuming something wrong with the flow?

LilSki

iTrader: (1)

You are backwards on the flow. The water pump pulls from the lower rad hose and pushes coolant into the block. Then when the T-stat opens it flows back to the top of the radiator and cycles through.

So that means there is always positive pressure in the engine block which allows it to flow through the heater core and return to the radiator. This flow allows circulation when the t-stat is still closed preventing hot spots and wild temperature swings before and after the t-stat opens. It allows the engine to warm up evenly.

Again if you were running that heater valve you would need the bypass as unless you were using the heat the coolant would not flow through the heater core. Without that valve you are good to go as you are.

87ROCZ

iTrader: (3)

Hey Kevin.... thanks for sticking with me on this.. I want to get this right before I go and fill the engine up with coolant only to find out I need to put something in or take something out.... I don't want any surprises when it comes to "Engine Fire Up Day"

You don't have the heater diverter valve just like me so I want to set mine up like yours... you said above "I used a 90 deg out of the intake and returned right to the water pump. "

So here is how I think you have it setup... correct me if I am wrong..

LilSki

iTrader: (1)

That is correct. If you set it up that way you would eliminate that long line running back to the radiator. But you would have to plug the port in the radiator somehow.

Here is how it looks with my heater hose routing. One is a little on the long side but they both go along the valve cover straight back to the firewall.



EDIT: This is a better angle


EDIT #2 just for the heck of it here is what my engine bay looked like not long after I got it. Those are the original hoses. This was right after i removed all the emissions junk.

87ROCZ

iTrader: (3)

Awesome! That's how I am going to be routing it then...

So was the before picture with or without Vortec heads? Have you ever had it dyno'ed or to the track?

LilSki

iTrader: (1)

The old pic is of the original LG4 305. The new motor is a true vortec 350 out of a 98 2500 GMC. I have never had it to the track or dyno as there are none around here. I didn't build it to be anything crazy but I estimate it to be in the area of 300 HP. A far cry from the 150HP the original 305 put out.

87ROCZ

iTrader: (3)

Cool man...

Is your car MAF? I like what you have done with the cold air intake... I am wanting to do something like this on my Camaro to get away from the dual snorkel intake....

LilSki

iTrader: (1)

My car is not MAF as the megasquirt uses SD. But there is a similar kit with extra rubber couplings for the MAF sensor.

darbysan

I used a heater control valve from a '96-'99 truck with the vortec engine. It is set up to continually flow water back to the radiator/water pump ( whichever one you connect to), and has the vacuum control for heat to the cabin. $15 at your local auto parts store. I tried plumbing the short hose from the intake to the water pump, but is is a very tight turn, and if the hose is not a formed hose, it will collapse.

Nathaniel92

So you have the heater control valve off a l31 fitted to the 3817/3816 intake? And ran a formed hose down to the water pump? Old thread I know.. At work atm. Just trying to get a plan together before tomorrow! My SDPC 3816 is sitting on my bench next to the stock one. I have that valve in a bin, came off a 97 GMC. This is a fantastic topic I just don't see a solution unless I mess with my EMC, 9th injector, etc. lol. Anyone just modify the fuel rail bracket? If so pics pls? Thanks! ... Almost forgot my specific details. The l98 in my 90 Formula 350 spun the bearings. I stripped it down and put everything on a 97 running, low miles l31 Tahoe block with 906 heads. Only aftermarket parts are Hooker Ceramic 2460's and this intake. Does it matter my stuffs off a 90? The generic instructions say it does?!? Thanks again guys!

darbysan

I ran mine from intake to control valve, and from control valve back to radiator ( i have the F-body radiator with heater hose input on the passenger side. If you don't have this connection on the radiator, then you can go directly to the water pump from the valve.

This eliminates the need for a short ( 3") secdion of hose form the intake to the water pump. Just plug the extra hole in the intake, or use it for a switch for your fans?