No Thermostat and Split Davies Craig water pump = Blown Head Gasket?

Re: No Thermostat and Split Davies Craig water pump. (stuka)

Fri, 06 Jan 2017 19:57:52 GMT

I tried this on my car, I had to give the cam a little shave to get one stud out. If you rotate the motor with the cam cover off you can position the cam in the best rotation position possible to avoid having to do this.

I didnt solve my unusual overheating issue though, and I would imagine the longer you leave a head not torqued right, the more likelihood for headgasket and warpage issues

Re: No Thermostat and Split Davies Craig water pump. (DamMR2T)

Thu, 05 Jan 2017 18:43:20 GMT

These are the 2 threads I've read over and over. Old but so are our engines.

http://www.mr2oc.com/61-3...0?page=1&_k=qgbf04

http://www.toyotanation.c...7?page=1&_k=di407d

Re: No Thermostat and Split Davies Craig water pump. (DamMR2T)

Thu, 05 Jan 2017 18:29:28 GMT

Doing this on the weekend as I misplaced my lube. Plan to follow no shoes ...i have read that post a couple of times before. The point of retorquing is to bottom out stud， and take up any slack after heat cycling. So I had planned to remove a stud at a time (need to loosen them to overcome friction)， to relube both ends and the nut face. Then use hex socket to install stud， followed by torquing the nut to 65nm...5 times per ARP instructions.
I Won't do it in stages 25，50，65 as that is for first time install when the rest of head might flatten further each time and probably helps position head and gasket.
No shoes says do it on cold engine. All the above is based on readings and a little logical (or illogical) thought， I could be wrong. At end of day I could be making it worse if it's already been retorqued， and was retorqued to 70nm and I only do 65nm.

If it's not oil I don't know what else it could be. Felt like oil on my fingers.

Re: No Thermostat and Split Davies Craig water pump. (Mrskylighter)

Thu, 05 Jan 2017 09:49:08 GMT

Here is a detailed reply from noshoes on MR2OC on the procedure he uses.

How to retorque ARP studs after engine break-in
I've been meaning to post this write-up for a while now. I've noticed over the years that MR2 enthusiasts do not take the time to retorque their ARP studs after engine break-in.

During the break-in period, the engine heat cycles, there are many vibrations that move things around, and other things that move the studs in the block. You have to re-torque the studs after this period, mainly to make sure the studs are seated in the block properly. If you do not, the head will eventually lift, and you'll get combustion gasses into the coolant system, overheating the car.

Here's what you do to keep this from happening:

1) Remove the valve cover.

2) Refer to the factory torque sequence (starting in the middle and working your way out in a criss-cross pattern just like you torque your wheels down), and work on one stud at a time. This torque sequence is shown below.

3) Break loose the first stud using a breaker bar.

4) Remove the nut completely. (A magnetic pick up toll works wonders!)

5) Use an allen key socket (A handheld tool just doesn't cut it here.) to bottom out the stud in the block.

6) Make sure the nut is cleaned, and liberally apply ARP moly lube (not oil, not multi purpose grease, but ARP moly lube) to the nut.

7) Torque the nut down to 65 ftlbs. (Not 70, not 75, but 65ftlbs)

8) Move to the next stud/nut combo in the torque sequence.

9) Repeat steps 3-8 in the correct torque sequence until you have done them all.

10) Clean the valve cover gasket mating surface with carb cleaner or brake cleaner. Use a razor blade to remove old silicone from the mating surface.

11) Apply a dab of Toyota FIPG (the black stuff) at each corner (where the semi-circle meets the flat surface of the head) of the 2 cam caps on the timing belt side, and the distributor shaft tunnel on the flywheel side. This will be 6 dabs of silicone total. (I have no idea how many times I have seen the valve cover installed without these dabs of silicone.) This is shown in the picture below.

12) Secure the valve cover with bolts or the 2SRUS allen key bolts using the factory grommets and you're good. Just DON'T use the stupid phillips head screws.

I hope this helps folks with rebuilt engines. If you do this properly, made sure your block and head were machined properly, and prevent detonation the best you can, you should not have a head gasket problem.

Happy motoring everyone!

hope it helps

Re: No Thermostat and Split Davies Craig water pump. (Mrskylighter)

Thu, 05 Jan 2017 09:41:22 GMT

tiff_lee
That picture isn't too clear but you are certain that's oil? I would of expected it to emulsify if the oil and water was mixing.

Mrskylighter
You probably already know this but just in case. Make sure you loosen off each nut before you retorque it up again (instead of just tightening them as they are now). I think arp recommend torquing them up in three stages also (one pass at xx, then slightly tighter and then final go at xx)

Wait what? surely you can't be suggesting the OP actually loosens all the nuts and re-torques from scratch? The OP has done over 400kms on that headgasket to merely undo the nuts and re-torque would IMO be a terrible idea given the situation who knows what lies between the sealing faces of the gasket and it could only get worse if you loosen it, not to mention the gasket has already been compressed (unless its a re-usable MLS gasket).

Not sure what ARP recommends for their torque sequence but if the final setting is a plain torque wrench setting with no additional angle for example 85N.m I would just check each of the studs at that setting, if it's an angle as well say 45N.m plus 90 degrees and you are going to loosen it I would be taking the head off personally.

I am suggesting that he loosens off one nut at a time and then retorques it back up.

Re: No Thermostat and Split Davies Craig water pump. (5SGTE)

Thu, 05 Jan 2017 09:01:50 GMT

dasic1
Make sure to only do one stud at a time. Put a mark on the bolt/nut and head, back it off then retorque it and see if the marks line back up or is pulled a little tighter. Then move onto the next one

I warm the engine first then drain the coolant before doing this

I have always done mine like this. If you don't loosen them, one at a time, your torque reading won't be true as you need to overcome the friction between the stud and nut. On something already torqued the force needed will be greater than the desired torque.

This is my understanding anyway.

Re: No Thermostat and Split Davies Craig water pump. (Admin)

Thu, 05 Jan 2017 08:42:51 GMT

Only retorque them - do not loosen!

Re: No Thermostat and Split Davies Craig water pump. (dasic1)

Thu, 05 Jan 2017 08:33:25 GMT

Make sure to only do one stud at a time. Put a mark on the bolt/nut and head, back it off then retorque it and see if the marks line back up or is pulled a little tighter. Then move onto the next one

I warm the engine first then drain the coolant before doing this

Re: No Thermostat and Split Davies Craig water pump. (tiff_lee)

Thu, 05 Jan 2017 06:08:09 GMT

That picture isn't too clear but you are certain that's oil? I would of expected it to emulsify if the oil and water was mixing.

Mrskylighter
You probably already know this but just in case. Make sure you loosen off each nut before you retorque it up again (instead of just tightening them as they are now). I think arp recommend torquing them up in three stages also (one pass at xx, then slightly tighter and then final go at xx)

Wait what? surely you can't be suggesting the OP actually loosens all the nuts and re-torques from scratch? The OP has done over 400kms on that headgasket to merely undo the nuts and re-torque would IMO be a terrible idea given the situation who knows what lies between the sealing faces of the gasket and it could only get worse if you loosen it, not to mention the gasket has already been compressed (unless its a re-usable MLS gasket).

Not sure what ARP recommends for their torque sequence but if the final setting is a plain torque wrench setting with no additional angle for example 85N.m I would just check each of the studs at that setting, if it's an angle as well say 45N.m plus 90 degrees and you are going to loosen it I would be taking the head off personally.

Re: No Thermostat and Split Davies Craig water pump. (Mrskylighter)

Sun, 01 Jan 2017 14:59:41 GMT

You probably already know this but just in case. Make sure you loosen off each nut before you retorque it up again (instead of just tightening them as they are now). I think arp recommend torquing them up in three stages also (one pass at xx, then slightly tighter and then final go at xx)

Re: No Thermostat and Split Davies Craig water pump. (Admin)

Sun, 01 Jan 2017 13:30:44 GMT

I wouldn't pull the studs out. I would just re-torque them in the same order as stated in the factory manual. Apologies if you said it earlier in the thread, though do you have the standard bolts, or ARP studs and nuts?
I would worry about causing undue stress on the metal of the head by removing bolts/studs one by one whilst the others are still fully torqued, and as you said, it may affect the seal of the head gasket and cause more problems.

Re: No Thermostat and Split Davies Craig water pump. (DamMR2T)

Sun, 01 Jan 2017 13:06:19 GMT

Thanks Guys.

The puddle under the car is quite possibly be overfilling of the overflow bottle as I was using a wrong meaurement on the pickup tube (It wasn't much coolant). I will be pulling the top off the engine and retorqing the head in next couple days. I'm just hoping I can undo the intake cam and tilt it to get to the hard to get to head stud, without having to take off the timing belt and tensioner. Anyone know what camshaft should be torqued to after reinstall?

I'm not going to have time to flush the whole system so won't know whether the oil in coolant is pre-existing or after the head stud retighten. Do you really remove the whole stud, to relube and tighten further into the block? Wouldn't this release previous pressure applied to the head gasket, and potentially end up with less pressure on the head gasket, even though stud bolt torque is correct?

Blocking the engine bypass pipes sounds like an option as I also have an external oil cooler. Got me wondering how pipes are currently setup. I will take a look at yours Admin at MR2WPC. I've also been considering putting a thermostat back in, as car can be a daily driver too.

Re: No Thermostat and Split Davies Craig water pump. (Admin)

Wed, 28 Dec 2016 09:43:34 GMT

I noticed that the diagrams had broken links. Sorry.
This one should help. I found it with Google though edited it.
I have an external oil cooler so have blocked the stock one. I have shown which ones are blocked in the diagram using a red circle. The one that isn't blocked is green.
Basically - the only one that passes coolant is the line from the coolant outlet near the distributor to the turbo, and then to the back of the water pump.

Re: No Thermostat and Split Davies Craig water pump. (Admin)

Wed, 28 Dec 2016 09:17:35 GMT

There is some good discussion about the cooling bypass pipes here - https://www.mr2australia.com/mr2play/FindPost/60243

Re: No Thermostat and Split Davies Craig water pump. (Admin)

Wed, 28 Dec 2016 08:59:51 GMT

Mrskylighter
I would definitely try re-Torquing the app headstuds. They may not have been checked after the engine was originally assembled with them.

I would just keep driving the car for every trip you need to make so the problem eventually becomes obvious.

I agree. Don't panic yet.
Keep driving it and continue to check the look of the oil and the coolant.
You may find that the puddle underneath the car could just be from too much coolant in the overflow bottle.
I did this once in my Commodore (filled the bottle too much) and when my wife drove it the parked, it overflowed onto the ground. She wasn't able to contact me, so she called the NRMA and they towed it home! There was nothing wrong with it.
Let us know how you go.

FYI I used to have a lot of cooling system issues and they went away after I bought the oversized Mishimoto radiator.
https://www.mishimoto.com/mishimoto-toyota-mr2-90-x-line-radiator.html
Seeing how you have no thermostat, you may want to block the engine bypass pipes to ensure that you have maximum coolant flow through the engine. I can show you exactly what I have done on my car at MR2WPC.
All of mine are blocked/disconnected except for the pipes that go to/from the turbo.

For others reading this that have a thermostat - this is not recommended unless you drill 6 x 2mm holes in the thermostat, otherwise you will find that the thermostat will not open early enough due to no hot coolant flowing to the back of the thermostat to tell it to open.