[Rock Ape]

Yep. Sent Billivista a note on this yesterday. Surge tank should empty out into the forward hole.

I was wondering about that...when I got my surge tank kit from schwanke it came with a hose to go to the front water outlet 3/4" . I called them and they told me yes the front hose.....also part of their kit included the freeze plug to eliminate the t-stat.

 

[patooyee]

Fuck it, I JB'ed it in. Seems to be in real good for now. I welded a small rod to the t-stat cover plate so that if the blockoff plate does come loose it can't flip up and block the inlet passageway.

Remote LS thermostat housing completed along with new inlet neck welded to pump. At first I didn't plan to use the t-stat housing so I cut the neck off to use on the pump. Plans changed and now I need a new t-stat housing but its on the way which is why only the base is bolted on for now.

J. J.

 

[BillaVista]

You're right. I've never looked at the diagram enough to catch that.

Front 3/4" label is return and suction side. The smaller 5/8" label is out to the heater core or the pressure side.

Yep. Sent Billivista a note on this yesterday. Surge tank should empty out into the forward hole.

Wooops That was a bit of a f*%k up! I swear I double-checked those diagrams :homer:. Thanks for the catch. Should be fixed up now.

On a related note - I recently read the follwing:

A large spring-loaded bypass valve rests on the bypass circuit seat when the thermostat main valve is closed, maximizing coolant flow available to the heater core at low engine speeds. The bypass control is calibrated to provide nearly constant pump flow, regardless of thermostat valve position, providing more uniform heat transfer charactristics and temperature control. The coolant returning from the heater circuit is directed at the thermostst wax motor which biases the controlled coolant temperature slightly warmer when the heater core is extracting heat, thereby improving heater performance.

My silly question of the day is - what happens in a stock car with an LS when the heater controls are off? Doesn't this block the flow of coolant through the heater core, and thereby also from returning to the FRONT 3/4" :laughing: port? I think I must be missing something here.

 

[patooyee]

I'm not that familiar wth those specific heater setups but doesn't coolant still flow through the heater core when the heat is off? The vent door is just closed that directs air through it? Its been a while since I worked at Ford but I want to say that that's how most of the heater setups there were. There was no valve that closed that blocked off coolant flow to the core whent he heat was off IIRC.

J. J.

 

[mj]

most dont use a valve in the heater circuit anymore

 

[BillaVista]

OK, so I think I have a theory on why some have troubles when blocking the heater ports and others don't.

The heater inlet port dumps coolant onto the wax motor - i.e. it is the temperature of the coolant returning from the heater circuit that determines when the T-stat opens.

If you have a T-stat like the one 95Geo posted,

where the "block off plate" has some raised reliefs that prevent the plate from completely sealing the heater out and heater in chambers of the water pump, then even if you block the heater ports, some coolant will circulate from the "out chamber" to the "in chamber" and this should function the T-stat just fine.

However, some T-stats (mine for example)

do not have the reliefs, so when the T-stat is closed the 2 chambers are sealed, and so if you have also blocked the heater ports, while the T-stat is closed, you don't have good coolant flow to actuate the wax motor. This would explain the overheating some have experienced - without flow, the engine would have to get really hot before the coolant just sitting in the "in chamber" got hot enough to open the T-stat.

That make any sense?

Now - if the theory is any good - instead of creating a loop between the heater ports - how about drilling 1-3 holes in the plate that blocks the 2 chambers, such that some coolant can flow between the two, allowing the T-stat to be actuated normally?

Geo? Bo?

 

[patooyee]

my stock tstat has 4 small holes in the blockoff plate from the factory.

J. J.

 

[BillaVista]

What's the approx. diameter of the holes JJ?

 

[patooyee]

Maybe 3/16? I can measure them tomorrow for you. You can see them in this picture:

They seem like they would allow A LOT of bypass circulation. It should also be noted though that my engine is from an SSR and SSR's are notorious for overheating. Its generally considered to be an airflow issue around the radiator and all the guys who soup up their engines replace their radiators with aftermarket units which are generally considered to be the solution. I am finding out over time that the SSR was a very odd conglomeration of car and truck parts.

I have also found out that there is a difference between the car and truck thermostats and t-stat housings. I am trying to find out for sure where the break is but from my prelim findings its appearing that the car t-stats have a smaller dia. seal than the truck t-states and the truck t-stat housings have a slightly larger bolt pattern than the cars. Yet if you go to a parts store they pull up the same part numbers for both. This may also be creating issues but I don't know for sure yet.


J. J.

 

[patooyee]

Those holes measure .196".

J. J.

 

[95geo]

Geo? Bo?

I think there are too many variables in peoples individual setup to really pin point the main issue. It could very well have something to do with not enough bleed through to the wax pellet or maybe people have put a thermostat in without the restrictor plate and blamed it on having a thermostat all together..... I'm not sure really, your theory has merrit but I dont think the cases are consistent or common enough to name that as the sole issue.

Maybe with the huge popularity these engines are getting, we'll be able to narrow down the good setups from the bad. The more people that run them the better off we all are.

 

[mcutler1]

i would like to bring this back to see if there have been any new results or attempts on everyones problem.
my cooling system is as Randy and KUla have mentioned below; 06' LS2 from vette-20,000 miles, blocked heater ports, steam lines to low pressure side of rad, temp sensor in 5/8 port, 180* tstat, -16an rad lines, yet runs hot in garage at idle-235, when revved over 2000 it comes down to 205 and no less,

I believe that this system in not a viable solution. As mentioned by Kula you have to have some sort of loop for the heater ports when running a t-stat to make this system work.

has this been tested and thought to be the culprit? i haven't pulled my tstat yet and not sure of the second plungers seal surface but sounds very likely to be similar to billa's theory here. any new thoughts on the sublect? everyone still going the freeze plug route?

OK, so I think I have a theory on why some have troubles when blocking the heater ports and others don't.

The heater inlet port dumps coolant onto the wax motor - i.e. it is the temperature of the coolant returning from the heater circuit that determines when the T-stat opens.

If you have a T-stat like the one 95Geo posted,

where the "block off plate" has some raised reliefs that prevent the plate from completely sealing the heater out and heater in chambers of the water pump, then even if you block the heater ports, some coolant will circulate from the "out chamber" to the "in chamber" and this should function the T-stat just fine.

However, some T-stats (mine for example)

do not have the reliefs, so when the T-stat is closed the 2 chambers are sealed, and so if you have also blocked the heater ports, while the T-stat is closed, you don't have good coolant flow to actuate the wax motor. This would explain the overheating some have experienced - without flow, the engine would have to get really hot before the coolant just sitting in the "in chamber" got hot enough to open the T-stat.

That make any sense?

Now - if the theory is any good - instead of creating a loop between the heater ports - how about drilling 1-3 holes in the plate that blocks the 2 chambers, such that some coolant can flow between the two, allowing the T-stat to be actuated normally?

Geo? Bo?

 

[patooyee]

I'm not sure if this helps anyone but possibly some research into Hondas could help here. Honda engines have used this bypass cooling system for decades now and people have been modifying, blocking of heater ports, and swapping those engines long before Chevy even put the first pencil to paper on these LS engines. Draggbody deleted his heater core in a Civic build he is doing right now and is having some of the same issues we have with the LS engines as a result. He is slowing working through it all on his own.

J. J.

 

[mcutler1]

Did alil testing today based on info in earlier post that randy and billa put in. Rather than drill holes in secondary tstat plate, mine was attached with an e-ring, so I just removed it. Seems to have done the trick, runs 200 @ low rpm or high, and at idle drops to 190. Under constant throttle also drops to 190. Full on testing at harlan ky this weekend.

Sent from my PB99400 using Tapatalk

 

[WideJ]

Bringing this back from the dead again. Is the freeze plug diameter required the same for truck water pumps as car pumps? 31mm? Rockauto has every conceivable diameter in stock, just reference a Dorman part number and BINGO.

 

[patooyee]

My truck pump was not 31mm. It was an oddball size that I couldn't find locally.

J. J.

 

[WideJ]

My truck pump was not 31mm. It was an oddball size that I couldn't find locally.

J. J.

Any idea what it was?

 

[patooyee]

No, sorry. It was a long time ago.

J. J.

 

[zebrajeep]

Called Turn Key today. They say Shannon Campbell, Loren Healey and all the guys who use their engines in KOH use the block plate with a hole in it, plugs in the heater hose openings and NO thermostat.

I have the block plate, heater hose plugs and a single stage thermostat 190 degree. Mine heats up to 236 before the thermostat opens, then runs at 210 to 220. I believe this is because in my setup the thermostat is seeing only the coldest water in the system! I either need to connect a bypass to the heater hose openings or remove the thermostat or use a much cooler temp (160) thermostat. If i reconnect a hose connecting the heater openings it will dump the hottest water on the wax motor.

I could also remove the thermostat and rely on the fan thermostat to cycle.

Thanks to all for helping me understand how the system works.