Ranger's Dec09 motor rebuild thread (lol)

#61

Ranger wrote:

[quote]1) You guys are shitheads. You are either “scanning” instead of “reading”, or, well, you’re just shitheads.
[/quote]

Ranger wrote:

[quote]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.
[/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”…[/quote]

We have to get our entertainment from somewhere…

#62

According to mail logs it has been delivered to your mail server.

#63

Got it and gave Chuck a call thx.

I pulled the rocker arm shafts off and did another drip test. Chambers 1-4 are terrific. No drips at all. #5 of course is stuck upon but fortunately it’s only about half way down so the piston didn’t hit. #6 exhaust has 12 drips/min, well beyond the 3 drips/min standard. It was probably beat up by the heat.

Rocker arms look ok and now that I’ve looked at the cam closer, it looks ok too. Could have been a lot worse. Probably need a new valve and valve guide, and a valve job on 2 chambers. Hardly enough to even involve an expert like Chuck.

Is a shame I pulled the oil pan off. Geeze that was a pita.

All the damage in the rear of the head. The rear. Hmm.

#64

Pic of stuck #5 exhaust

#65

I was gonna quote ilateapex as well because I was confused when he was talking compression test and needing to have it at TDC. I also just thought he had confused leak down and compression test. The needing two people confused me even more as I have done many compression tests by myself as well. You just lay the gauge down and go get in the car and crank it the same amount of times normally 5 or 6.

#66

King Tut wrote:

The hose for my compression tester is pretty short, and at age 47 now, my ability to see a little gauge needle from several feet away isn’t what it used to be. It’d hard for me to do a compression test by myself.

My screwup about TDC, made all the worse because I ignored lateapex trying to point it out to me, is hard to forgive. When I do (or say) something stupid, I beat the shit outta myself about it for weeks.

#67

Just shipped the head out to Chuck Baader.

Since I think we’ve found the cause of the clanking I’m on the fence re. inspecting the rod bearings. I went on line to order some rod bolts, since they aren’t reusable, and found that they cost $6 ea. Christ allmighty, you can get a set of headbolts for $20 but rod bolts are $6 ea? I’m like so out of money. I bought 4, which is kinda pitiful.

I would hate to find that perfectly good rod bearings fail next Summer only because in Dec2009 I couldn’t resist temptation and I had to pull them apart and look at them.

#68

13

#69

kgobey wrote:

[quote]going to edit.

Dave Knaack, Neenah Wisconsin owns a junk yard/Auto Breakers/Salvage yard… He deals in Imports.

He’s an SCCA & MCSCC racer. Tell him you are a racer and need a solid motor for an E30 325.

Fixing this motor has gotten you into all sorts of work that to be honest is not worth the money or time considering the cost of working substitutes. :blink:[/quote]

Thanks, but I have a spare motor and a 2nd spare bottom end. But this is my cherry motor with new 0.020 pistons, new bearings, new head and cam. I decided to fix my monstor 149 horses of fury motor rather then put in the high mileage spare. Besides, putting the head back on once Chuck’s fixed it, is no big deal.

Plus, with my luck, I’d put the spare in and then by the end of it’s first weekend it’s OP would be at 30psi at redline. And I’m sick of bearing problems.

#70

I heard that head bolts are stretch bolts but rod and mains are not and therefore are reuseable…is that true??

Al

#71

FARTBREF wrote:

[quote]I heard that head bolts are stretch bolts but rod and mains are not and therefore are reuseable…is that true??

Al[/quote]

I think that the school solution is that rod bolts are not reusable. That being said…

There is a procedure that (apparently) some experienced mechanics do on their own cars, even if they don’t (so they say) do it on customer cars. It’s something along the lines of instead of using the two stage 14ftlbs + 70deg. they do a two stage to 22ftlbs. It’s something like that. Hopefully I wrote it down somewhere.

As usual, that doesn’t come from personal experience, that’s just something I came across.

#72

Ok, here’s the scoop on water flow in the thermostat. I just spent some time eyeballing the insides of the thing. Here’s how it works…

Thermostat closed. When the motor is cold the return from the radiator is blocked. Therefore water from the front of the head and water from the heater (meaning rear of the head) goes right to the pump. All water that goes to the pump is pumped into the front of the engine block.

Inside the block is a big open cavity with the cylinders inside looking like a submarine’s missile chambers. The block has holes on top that go to the head, so water is free to flow up there. The actual water flow that occurs tho, depends on the locations of the water inlet and outlets. Obviously the water pump is on the front of the block, so water flow in the block and head are entirely a matter of the location of the water outlet.

Thermostat open. When the water is hot the radiator return line opens up and feeds right to the pump. Pump to block to head. The water from the front of the head goes to the radiator. And here’s the fun part…the water from the heater (rear of the block) goes to the pump.

Ok, so what does this mean…

  1. The efficient route for general cooling is heater valve closed (rear of the head blocked off). This means that the only water to hit the pump is cooled water from the radiator. I think that this is what Jim and Chuck were saying, and they are (not surprisingly) right. At least I think they are. I’m sure that they’ll sleep better tonight knowing that Scott thinks that they’re right.

That was sarcasm.

  1. But here’s the kicker. If there’s no way for water to flow out the rear of the head, water flow in the back half of the motor is going to suck. And the only way you are going to improve water flow in the rear of the motor is with the throttle body hose and the heater hose at the back of the head.

It’s not perfect. Introducing that hot water to the cooled stream from the radiator just before it hits the pump is not ideal. That will affect overall cooling efficiency. But it will result in better cooling of the rear of the head.

So I think that the choices are along these lines…

  1. Block off the back of the head so water can’t flow around the rear of the engine. Front of the engine runs at 200deg and rear of the engine runs at 240deg. I’m pulling these temps out of my butt of course.

  2. Entire motor runs at 210deg. Not 220deg because the higher the temp delta the more efficient cooling is. And if your engine is running hot, just put some tape around your radiator to trap more air.

Thermostat open (hot)

|–<--Radiator–<—<–|
|–>Pump–>Block–>Head–>Heater–>-|
|-----<-------<------------<--------<----------|

#73

One other thing to consider…the block and head are a pressure vessel pressurized by the water pump. As such, all points in the vessel have the same pressure. Water flows to the cylinders first, and then it is a regulated flow to the head because of the size of the holes in the head. Theoretically, all points in the vessel should receive the same amount of water. Remember, also, that flow increases with rpm…so cooling does take effect at the rear of the head. I really don’t think there is a significant delta T over the length of the head. If there were, we would be killing motors regularly by racing and we are not.

As a side note, I run a double pass Ron Davis radiator with a 160 degree thermostat. My water temp gauge is in the upper radiator hose between the thermostat housing and the radiator. Hot days usually see 170 degrees F at that point, even with the 160 degree thermostat. Also note, cooler engines make more power. YRMV…CB

#74

It’s perilous to disagree with a master. But if I’m wrong about this, which won’t shock anyone, I still don’t see what I’m missing.

I agree that the block water jacket and head water passages will be the same pressure. If the sum of the holes in the head were the same or less then the size of the thermostat opening, then all holes in the head would flow water in order to fill the hole to the thermostat. That would take care of water flow for block and head.

But the holes, at least where they are visible at the head/block interface, are pretty big. Certainly the sum of those holes is bigger then the thermostat hole. On the otherhand if those holes are choked down in diameter inside the block, then regulated flow idea works. But are those holes choked down?

Delta T over the head and killing motors. Ya, that’s a great point. Those BMW engineers were no dummies. It makes no sense for them to design engine cooling such that the heater has to be on for the motor to be cooled evenly. Especially since the heater would have been off during the most stresful temp conditions, idling in line at the Tijuana border in Aug. or something.

Because it just makes no sense of engine cooling to be hosed up like this, I’ve been assuming that I’m just missing something. So maybe that answer to this all is just that the holes are choked down inside the head.

But would you agree that engine failures tend to be in the rear of the engine?

I wonder if it would be useful to put in some big-ass T in the hose from thermostat to the top of the radiator and then pipe the rear of the head to that. I’d hate to dick around with the BMW engineers design an accomplish no more then the demise of engine #4.

And of course Chuck Taylor might not be impressed with it either.

Someone needs to go marry some German chick and discover that her dad helped design the M20. ScottM’s chickless right now, isn’t he? Or Bill could just add one more to his harem.

#75

One thing’s for sure…you have to have a thermostat. I’m not sure how water would flow in the absence of a thermostat but it’d certainly be a goatscrew. Darn little water go thru the radiator.

#76

cwbaader wrote:

Makes sense to me. Even though water flow may be greater at the front of the head than the rear, isn’t water a good enough conductor of heat that the “hot” won’t just stay at the back of the head? Both the metal of the engine and the water cooling it would tend to disperse that heat pretty effectively, no?

#77

I’m not sure if Scott McMcmcmcmcany is chickless or not, but assuming he was isn’t hard to understand…is it? Doesn’t he date that hard charging manly man Jones? :wink:

#78

I am pretty sure that the holes in the head gasket are the regulating factor to water flow from the block to the head. Like Chuck said, the system is under pressure, not just a pump pumping fluid along a path where the end and begining are open to the atmosphere.

Also, When doing compression check jump pins 11 and 14 to turn the starter. I figured everyone know this but seeing how some of you have guys in the car with the key turned I guess not. When you do this make sure the key is off and the car out of gear. I purchased a momentary switch from Radio Shack and hooked it to two wires that get stuck in the diagnostic connector. I just push the button when I want to turn over the motor. All this does is turn the starter. So you don’t need to disable anything else. Just make sure the key is off.

#79

ilateapex wrote:

[quote]
Also, When doing compression check jump pins 11 and 14 to turn the starter. I figured everyone know this but seeing how some of you have guys in the car with the key turned I guess not. When you do this make sure the key is off and the car out of gear. I purchased a momentary switch from Radio Shack and hooked it to two wires that get stuck in the diagnostic connector. I just push the button when I want to turn over the motor. All this does is turn the starter. So you don’t need to disable anything else. Just make sure the key is off.[/quote]

Hey, this would prime the oil pump w/o having to remove the fuel pump relay too. Nice.

#80

Or you could just prime the pump the easy way with an electric drill. CB