My truck never gets over 190 with my thermostat. I would think anything over 220-230. What temp stat are you using?
My truck never gets over 190 with my thermostat. I would think anything over 220-230. What temp stat are you using?
From GM performance parts:
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 NPSF boss on intake manifold to the water pump.
What intake are you using? It sounds like your gonna need the bypass hose. Read through the beginning of this post. Lots of info
https://ck5.com/forums/threads/vorte...i-need.298868/
Last edited by Stokes1114; 06-17-2017 at 07:15 AM.
Getting late but excited about digging into the cooling issues and the timing tables tomorrow. I did open the zip file right quick and noticed a few things. Oh yea, I am running 16168625 and $E6.
As far as screenshots in the jpeg file - what program is this?
What is the equivalent table name for the PE/COT spark advance correction and is the equivalence ratio going to be something I have in my tune/BIN (this doesn't look familiar at all)?
Same question for PE EQ ratio - I know I have PE but this table and the EQ ratio are not something in my BIN as best as I can tell.
I am running the GMPP TBI to Vortec intake. Expensive but I needed EGR to pass emissions (glad that's over). After reading through some other posts and various other internet sources I decided to try the holes in the thermostat. It seemed simple enough and besides, I don't think my pump has the external provision for the bypass. I remember buying a new pump for a 1993 truck during the rebuild (looks like I should have bought a 1996-1998 pump).Originally Posted by Stokes1114
Stokes, if you don't mind checking the orientation of your heater core hoses I sure would appreciate it.
There is some good info here on the Vortec coolant bypass
http://www.gearhead-efi.com/Fuel-Inj...Manifold/page2
I run a 94 water pump because the factory coolant bypass passage now works with the hole I drilled in the Vortec head.
Last edited by Kitch; 06-18-2017 at 01:13 AM.
Dude! What a great thread. Thanks for this!!
Just have a sec to reply, I looked at your pic and your heater core setup is identical to mine. From the back of intake it goes to the core then from core to the radiator, just below the cap. Ill have more time in a bit so Ill be back with some more info for you.
Maybe you could look at temporarily bypassing your heater core so the return goes straight back to your radiator and see if that makes any difference?
More updates:
1) What is considered the normal range for ECT? No consensus. Probably 190-205 depending on your thermostat rating.
2) At what point would you stop the truck and wait for it to cool down? No consensus. I have set my personal number at 229 or greater - as long as there was no audible boiling or overflow. If there was boiling or overflow I would immediately stop the truck.
3) Could this be caused by me having the heater core hoses hooked up backwards? No. It does not matter how the heater core is connected on a 1993 TBI truck. There is not a heater control valve and there is no flow restriction in the heater core. My particular problem was that vortec heads were blocking internal coolant passages that allowed for coolant to bypass around the thermostat. The small amount of bypass flow is needed to prevent local hot spots in the cylinder heads.
Even more updates:
1) Logging knock counts continuously but no knock retard: I was not logging knock counts continuously. The knock counter is cumulative - like your odometer. Jim and steveo explained this well (see above)
3) Computer blips: No answer yet.
4) Block learn cells jumping and causing some drive-ability issues: This can be tuned out. Once I resolve this issue for my setup I will come back and post it here.
Thanks,
AC
People call it a bypass but it's not a bypass for the thermostat to let coolant flow past the thermostat into the radiator. It is a path that allows coolant to circulate in the block and heads with the thermostat closed.
In a typical installation the heater hoses are connected to the intake beside the thermostat and to the port on the side of the water pump. This allows coolant to circulate in the block just fine with the thermostat closed. The water path is from the pump into the block, up into the heads, forward into the front intake coolant crossover, out to the heater core and then back into the pump.
I don't know the heater configuration on your application though. Is it one hose to the intake and the other hose to the radiator? That configuration should still cause flow in this path - pump to block to heads to intake to heater to radiator to pump.
In both cases, the heater hose is likely connected to the passenger side of the intake but this just means the coolant flows from the drivers head to the hose passing by the thermostat so it detects the coolant temperature.
If the heater is configured so the hoses go to the water pump port and the radiator then that would not allow coolant to circulate in the block. I can't see the heater working very well either though since it would be using coolant from the radiator and not right from the engine.
Your description of the internal block passageway is wrong. The coolant flows down from the head into the block and then into the pump, not the other way around. When the pump pushes the coolant into the block then heads and finally up to the intake, the passage lets some of that coolant flow back to the pump.
In your particular engine you might have been getting a little air at the thermostat when cold so it wasn't detecting the hot coolant as quickly when the engine was started.
Last edited by lionelhutz; 06-23-2017 at 07:57 AM.
The stat is whatever is stock. I can't remember but either 190 or 195.
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