Vortec heads- cold weather issues?

[MikeB]

Yeah, as mentioned above, this may be an inexpensive way to get heat into the carb and plenum:

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In order to pass a visual emissions equipment check many years ago, I made a "heat stove" from sheet metal that sat my headers. Air cleaners of this type must be a dime a dozen. And the hose is a part Dorman sells.

Also, a radiator fan blowing cold air (for the first several minutes after start-up) at an open element air cleaner isn't helping your situation. And in the summer you have the fan blowing probably 150-180 degree air into the carb after warm-up. If you don't go to a stock type air cleaner housing, I'd suggest at least fabricating a thin piece of sheet metal that sits inside the filter element on the front 90 degrees of the filter housing.

 

[Daveo91Burb]

There are factory heat stoves for the rams horn manifolds that the OP said he's running. I still run the original rams horns on my Vette and there's a heat stove on the passenger side. They're available new in Vette catalogs, but probably spendy.

I didn't know the part about the factory BBC TBI adapters. So when the BBC went to TBI did they just continue to use a q-jet spread bore manifold instead of a dedicated TBI manifold like that on the SBC? Was the plumbing there for warming the mixture? Hmmm...could be an intriguing solution.

 

[68post]

I didn't know the part about the factory BBC TBI adapters. So when the BBC went to TBI did they just continue to use a q-jet spread bore manifold instead of a dedicated TBI manifold like that on the SBC? Was the plumbing there for warming the mixture? Hmmm...could be an intriguing solution.

Yes, a stock iron Qjet intake.(early versions did)
There are fittings on the adapter specifically for warming. I don't remember exactly how they're setup , and my '90 3+3 is gone - so I don't have a reference here.

 

[77 K20]

Well it has been slow going for me to swap out the manifold... but finally got it in.

I had to get a taller neck on the thermostat housing to make room underneath for a 90* elbow to send coolant back to a 45* fitting next to the TBI. It then flows under the TBI, then up and out of another 45* fitting and then back to the water pump.

I also have a regular fitting on the other side of the intake manifold that goes to the heater core and then back to the radiator.

Also shown in this picture is the new improved throttle cable bracket. I couldn't find one of these last year. The one I was using was too flimsy.

Don't know how well it works yet- all I had time to do was start it up (it was 70 degrees here today) and check for leaks and set the timing. I need to fix a wheel bearing before I can drive it. (and 5 out of 6 of the allen bolts for my manual hub are seized).

 

[Daveo91Burb]

Looks pretty good! Will be interested to see if it solves your problem. Think you'll have to wait till next winter to find out?


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[77 K20]

I drove it around today- but we seem to be having a heat wave right now. It was 80 degrees today. One thing that is better is my coolant temperature sensor in the head now just gets up to 180 degrees and stays there. No more going up to 190 then back to 170 every 12 seconds or so. I don't know if this is from a secondary coolant bypass or because of the Stant thermostat I installed...

I also noticed with the new intake manifold my vacuum at idle is even higher. It is 21" to 21.5" now. Never seen an engine with vacuum that high.

Weather is going to turn cooler and rainy this weekend. Supposedly the low on Sunday night will be 36 degrees. I have to work Sunday night so I will see what happens at 3 am.

On a slightly different note- I ended up buying silicone heater hose for the external water plenum under the TBI. Gotta say I'm real impressed with the stuff. Normal heater hose isn't nearly that flexible. It can flex and bend without kinking.

 

[77 K20]

The low last night was 40 degrees.. a little warmer than I was hoping. The cloud cover from all the rain held some of the heat in. But after work at 3am the truck fired right up, I let it idle for about 30 seconds and drove out of the parking lot at work. Not a single pop, chug, missfire.
So I have high hopes next winter when it gets into the negatives that things will be much much better.

 

[crazy4offroad]

Glad you followed up on this. I'm wondering if it may have just been an intake manifold gasket not sealed 100%. I have some chaos with mine I haven't been able to line out and it has me wondering about how good of a seal the intake is getting. The bolts (and as few of them there are) for the intake seem to leave a lot to be desired.

 

[77 K20]

I'd like to think that the manifold was sealed- as it was a complete crate motor from GM. In my previous troubleshooting I did spray all the edges of it with carb cleaner to see if it changed idle at all. It didn't.

 

[4WDKC]

Any update on this after the frigid temps we just had?

 

[77 K20]

I thought I updated this thread- but apparently not. So after changing to this manifold I found that for every 3-4 trips of me driving to and from work I would have to add coolant. I had the intake manifold gaskets changed. Still used coolant.
I bypassed the coolant plenum under the TBI and the problem went away. Edelbrock had NEVER heard of such a thing! (of course).
So due to lack of options I bought a SECOND intake manifold and had it installed (I was too busy at work to do it). And things were great- for about 2 months. Opened the hood one day to find I'm a bit low on coolant. I removed the TBI and looked down into the intake manifold and there was my coolant. Little drops of it in the waffle hatch pattern in the intake.
Called Edelbrock AGAIN and they were really no help at all.
So out of desperation I had a tube of alumniseal lying around. I drained out a few inches in the radiator and warmed up the truck. Slowly added it so it wouldn't clump. Then I swapped out my 16 psi radiator cap for a 7 psi cap. It has been about 2 months and so far no coolant loss.

This manifold can be used with exhaust thru that passage. That would probably be the best option.

As far as the cold snap... It got to -21 degrees here. I found the truck would start then immediately die once. Then it would start and say running the second time. After 15 seconds of idling you could hear it misfire (pop, pop..) out the exhaust a bit. This is from fuel puddling in the cold intake. I'd let it idle for a few minutes then slowly start driving away. After driving a mile only doing about 35 mph then there is some heat in the manifold and the misfire and popping was almost completely gone away.

Exhaust would get the manifold temp up much quicker. The downside would be summertime you wouldn't need it. Maybe a way to have a shut off valve to block it off for the summer?

The coolant going thru it does do its job after 5 minutes or so- just am not impressed with the casting of the coolant passage.

 

[jwgreen]

Hi guys,
New to the forum and was just browsing when I read this thread. I did a little research and found a possible solution that might work better as it appears you can turn it on and off whenever you like. I know nothing about cold weather problems as I live in the south. Take a look and see what you think. http://www.walkerproducts.com/products/efe-heater-gaskets/

 

[77 K20]

Interesting. Wonder how well that would work. I had thought about using a diesel air heater or the VW coolant glowplugs but figured it would be more trouble than it was worth.

 

[crazy4offroad]

The image shows a V-8 and 4 barrel but the drop-down menus seem to only allow for newer model scooters?? A search in their search bar didn't help either.

 

[crazy4offroad]

https://www.summitracing.com/search...5&SortBy=BestKeywordMatch&SortOrder=Ascending

Many of these things look like they may restrict airflow unless it was used in a partial airflow warmer capacity on a stock snorkel-style air can, except the sensor-looking doohicky with the large heater coil on it. None seem like a great solution though really.