602 cooling lines question.

[DaveBauerSS6]

Helping a friend and both new to crates, bought used 602 and didn't have the bypass hose at the front of intake to water pump.
What's it for?
Will it work on the top of the pump; the side inlet is covered by the alternator?

[rubbinsracin]

I'm not sure I'm understanding what you are talking about exactly, but if you are talking about the two holes in the front top part of the intake, that is where people put water temp, pressure, dummy lights, that kinda stuff.

[brad hibbard]

there is no provision for installing water lines on a 602

like the last poster said the 2 ports on the front are for temperature senders

there are none in the back of a 602 for circulating the hot water from the heads

the two in the middle should NOT be used for racing purposes----they are to heat the air/fuel mixture on a street car in cold weather------we actually want to cool that area, I usually leave that passage open to air it helps to prevent carb boiling and vapor lock

Brad

[DaveBauerSS6]

The port is on the drivers side between the head and the thermo housing. Its a 3/8 pipe plug with a hole about 3/16 to 1/4 size behind it to the water jacket. You can see the port thru the thermo mount. Several guys that have bought new 602s say it is in the info that comes with the motor. We are looking for a copy. GM recommends it be plumbed to the lower hose area of the water pump?
Sorry about the vagueness of the question.
Thanks for any help.

[brad hibbard]

are you talking about the very front of the intake?----not top but front

[DaveBauerSS6]

are you talking about the very front of the intake?----not top but front

Yes, the hole faces forward.

[brad hibbard]

OK---now I know what you are talking about

that hole is in both 602 and 604 intakes and we have never used it in either---we simply plug it with a 3/8 pipe plug

I will try to find an information pack that is sent with a 602 engine and read closer than I have because i don't remember reading anything about that

If you find some actual lterature about plumbing it please post it so we can all learn from it

Brad

[DaveBauerSS6]

OK---now I know what you are talking about

that hole is in both 602 and 604 intakes and we have never used it in either---we simply plug it with a 3/8 pipe plug

I will try to find an information pack that is sent with a 602 engine and read closer than I have because i don't remember reading anything about that

If you find some actual lterature about plumbing it please post it so we can all learn from it

Brad

OK working on it.

[JAMESGANGRACING]

Brad, you say you just remove the 2 center plugs and leave them open?

[DaveBauerSS6]

Have the manual that comes with a 602 purchase.

Quote.
Title: CT350 Circle Track Engine 19258602- specifications
Rev 19ja10
Part # 8896057
Page 2 of 33
Cylinder heads: Last paragraph - 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 side). Suggested routing is from the 3/8 NPSF boss on intake manifold to the water pump.
End Quote.


Some guys read this and have the bypass and others don't. Will call GM hot line Tuesday and question the purpose and the placement.

[sj valley dave]

Hey Dave, are you helping out a LLM or a Sport Mod with the 602? Who's car? Hope to see you guys next week...Going to try and get the DLM down to Bako, unless Johnny's wife has different plans for his Birthday next Saturday...LOL

[brad hibbard]

Brad, you say you just remove the 2 center plugs and leave them open?

yep----anything to cool that area of the intake will help HP

[DaveBauerSS6]

The question was from Loren DeArmond, IMCA Northern Sport Mod. But since we started talking there is more questions on why and where. Some motors are on 40 plus nites without the bypass and running fine?? Not questioning GM , just want to understand.
Might come watch, been busy at work and 2 motors to finish.

[DaveBauerSS6]

GM Tech Hotline 866-453-4123 Press 2 then 4 for performance tech.

The bypass is to release air from the block to the intake via the thermostat passage. The air is trapped by the Vortec head design. In order for this to work the water pump you run must have the passage drilled just below the pass side lower water pump bolt. A lot of the cheap pumps have this blocked. Recommended port on the pump is the side next to the lower rad hose, but he said the top port on the pump would work.
Hope this helps, the tech line was great, no waiting. They also give you a case # and the followup call goes quick.

[DaveBauerSS6]

Those are both top end companies that know cooling. It would be a good question for them also.