Ranger's Dec09 motor rebuild thread (lol)

#21

Ranger wrote:

Those are locking nuts and are one time use. Just order up a bunch of them and replace them each time you take them off and this problem won’t occur.

#22

Re. nuts. Ya, that’s probably the right idea. I’ll order some nuts.

Re. Steve’s WP switch. Where did you put it in the system?

Re. AKG block-off kit. I checked out the site. AKG seems to have some cool stuff, especially for chassis reinforcement. I think that block off kit is the wrong thing tho. It looks to me like that blocks off the heater hose at the back of the head and also at the thermostat. I’d fabricated block-offs for those last Spring. The hose that failed is the little one that goes from the block (near the starter) to the throttle body.

#23

Ranger wrote:

:laugh:
“I” think “I” put it in one of the rad hoses using an in-line adapter with NPT fitting.

Since “I” was only concerned about pressure once the temp was high enough to open the t-stat, “I” didn’t care where in the system the switch was located.

#24

Why does it take 2 people to do a compression test? And why does it have to be at TDC? are we talking leak down? still, why 2 people.

I don’t think loss of coolant or pressure is an automatic overheat. Maybe sitting still but not moving.

Michael

36

Great Lakes Region

#25

Steve D wrote:

[quote]Ranger wrote:

:laugh:
“I” think “I” put it in one of the rad hoses using an in-line adapter with NPT fitting.

Since “I” was only concerned about pressure once the temp was high enough to open the t-stat, “I” didn’t care where in the system the switch was located.[/quote]

You’re quote key stuck or are you perceiving ill treatment that was, I assure you, unintended? Maybe I should get a Gasman winky.

Reason I asked about the location of the pressure switch is that 6psi isn’t much. I was thinking that it might be possible for there to be pressure variations in the coolant system such that some locations might be better then others. I don’t know anything about pressure behavior in the coolant system and if a person doesn’t ask they don’t learn.

#26

ilateapex wrote:

[quote]Why does it take 2 people to do a compression test? And why does it have to be at TDC? are we talking leak down? still, why 2 people.

I don’t think loss of coolant or pressure is an automatic overheat. Maybe sitting still but not moving.
[/quote]

Re. compression test. One person runs the starter and the other reads the gauge. Often a 3rd person is useful too. 3rd person can stand there and say “Hey, you forgot to turn the crank and move that piston to TDC”.

Re. loss of coolant is automatic overheat. Depends on how long it runs without coolant I suppose. But whether or not the car is moving doesn’t matter. Sure, the radiator gets lots of air if the car is moving, but as soon as the water level drops below the water pump, then water stops flowing. And running the motor hard on the track creates a helova lot more heat then idling sitting still.

Heat production is roughly proportional to power. Power required to idle is what, 3hp? That means WOT generates ~50X as much heat as idling.

The oil temp gauge hit 270deg. My perception is that the upper safe limit is around 250deg. Sure, oil provides some cooling, but not a helova lot. I have temp sensors before and after my big aftermarket oil cooler. At normal operating temps it seems to be good for ~17deg of cooling. Oil just isn’t as good of a heat transfer medium as water because oil has a lousy heat xfer coefficient.

#27

steve’s using the royal “I” - with all due respect of course :laugh:

#28

Ranger wrote:

[quote]Steve D wrote:

[quote]Ranger wrote:

:laugh:
“I” think “I” put it in…[/quote]
… quote key stuck or are you perceiving ill treatment …[/quote]
Not stuck, no perceived ill treatment. Just a weak attempt at humor since I didn’t install the switch so I can’t say for sure where it is located.

My rudimentary understanding is that pressure in the system is equal throughout - equal enough for our purposes, that is (assuming an open or gutted thermostat). If the pressure drops to atmospheric you have a leak. If you don’t have a leak, the pressure is well above the switch’s activation point (when at operating temp).

#29

[file name=coolant_path960.jpg size=177827]http://spece30.com/media/kunena/attachments/legacy/files/coolant_path960.jpg[/file]

Take a look a this and tell me what I’m missing. I submit that by blocking off the coolant hoses in the rear that go to the heater core, we cause coolant circulation problems.

My hoses #11 and #12 are blocked off. Those hoses are just flat-ass gone. I checked with some of y’all before I did that, so it wasn’t just my own wild-ass idea. But now look at the coolant flow diagram. The critical water flow is 2 --> 4. It is only that coolant that cools the block and head. There are only 3 ways for coolant to go from 2 --> 4. The first way can be discounted because it’s the silly throttle body loop. The second is 2->3->4 that goes thru the thermostat housing where it connects to the block. There’s no real “hose” in that route. This coolant route would not flow any water to the rear of the engine.

It’s the 2->3->11->12->4 loop that cools the rear of the engine. And mine’s blocked off, and it’s blocked off on some of y’all’s motors too. In the absence of that loop water would not flow, it would just sit there. And cooling is all about flow.

Ok, that’s my theory. What am I missing?

Credit to Steve for the diagram.

#30

The heater hose circulation path isn’t important. Unless the heater is in use, that path is blocked by the heater valve. So eliminating that circuit is a non-issue. I doubt that it really matters, but the hoses that connect to the throttle body heater always have circulation. It would best (and safest, I suspect) to loop those.

You won’t have cooling system failures if the the rubber and plastic parts are replaced on a timely basis. The first thing I do with an E30 is to replace the radiator, expansion tank, cap, thermostat, water pump, and all hoses. The only exception to that is if I have proof that all, or part, has been replaced in the last year or so.

#31

jlevie wrote:

[quote]The heater hose circulation path isn’t important. Unless the heater is in use, that path is blocked by the heater valve. So eliminating that circuit is a non-issue. I doubt that it really matters, but the hoses that connect to the throttle body heater always have circulation. It would best (and safest, I suspect) to loop those.
[/quote]

You make a good point about the heater valve, but the way my hoses were set up origonally, there was a T in hose that went to the heater. That T allowed water to go directly from the rear of the head to the thermostat cluster regardless of the heater valve.

My parts car was the same, but I don’t know about others.

#32

That would be a late model (from 9/87) cooling system. The stem of that tee hose goes to the reservoir. One end of the bar goes to the thermostat housing and the other end of the bar to the heater core. There would have been a short hose from the back of the block to the other heater core connection. If you eliminate the heater, you can use a block off plate on the rear of the head and either plug the end of the tee hose that would connect to the heater core, or substitute a plain hose for the portion that ran between the reservoir and the thermostat housing.

#33

jlevie wrote:

Rightly or wrongly, the stem of my T’s went to the heater.

If you block off the hose at the rear of the head, which I did, how does coolant coolant flow out of the block/head at the rear of the motor?

#34

I’d take a picture of how that hose is supposed to be installed, but with the intake in place you can’t see hardly anything. If I get inspired, I’ll put a hose on one of my spare engines and take a picture of that.

Coolant only flows out of the rear of the head when the heater is in use. When the heater isn’t used coolant flows into the head from the block, then through the head and and out to the radiator. Heater and throttle body heater circulation are before the thermostat so that heat is available before the thermostat opens and so that full heat is available in cold weather when the thermostat is only partially open.

#35

jlevie wrote:

[quote]
Coolant only flows out of the rear of the head when the heater is in use. When the heater isn’t used coolant flows into the head from the block, then through the head and and out to the radiator. Heater and throttle body heater circulation are before the thermostat so that heat is available before the thermostat opens and so that full heat is available in cold weather when the thermostat is only partially open.[/quote]

Well, ok, but my point is that the diagram seems to indicate that the hose connection at the back of the head is critical to cooling flow at the rear of the motor. And if that is blocked off then I can’t figure out how water would flow at the back of the engine.

#36

The diagram doesn’t indicate flow with and without the heater being in operation, thus it is a little confusing. Coolant flows from the block up into the head, then along the head to the front and out.

#37

jlevie wrote:

Agreed, except for the “along” part. The coolant flows into the front of the block. And in the absence of the hose at the rear of the head, the only path for the coolant seems to be out of the front of the head into the thermostat. In at the front and out at the front. Therefore, so my theory goes, the water at the rear of the block and head would be fairly stagnent.

#38

Ranger…plug the damn hoses. My motor ran 15 degrees cooler after plugging…before mine were looped. Also, if you loop them, you are bypassing water that should be going through the thermostat. Study the thermostat housing. CB

#39

I started this topic by saying “tell me what I’m missing”. And I still don’t understand what I’m missing. Looking at the diagram the water flow would seem to be completely stagnent without the hose at the rear of the head. I’m fine with being wrong, but I’d like to understand why I’m wrong.

What if your motor only seemed to run cooler because the coolant was no longer extracting as much heat from the rear of the engine? Possible?

When the M20 fails in one way or another, isn’t it usually a failure in the rear of the motor?

#40

As I said, look at the thermostat housing. The thermostat actually blocks one path and opens another. The water flows to #1 cylinder back and up through the head and out the thermostat housing. The thermostat stays closed directs and water to recirculate through the motor until temp is reached…then it opens and allows water to the top of the radiator for cooling. Some of the water is also run through the heater. That water bypasses the radiator…that is why you want the hoses plugged as opposed to looped. Jim put me on to that. CB