MLS question (oozing head gasket )

[spf_lexus]

Just gave my 1uz a valve job and once finished my driver side has a "wetness"
at the front of the block (the only head stud available w/o removing anything). And it's this front corner thats the problem. I drove it 1200 miles from california to colorado and it managed to stop w/ a can of coolant leak stop but now i can see the wetness again. My car has not been going through coolant lately and i know at it's worse it only appears "wet". I can wipe the wetness away at idle and then the wetness at the seal re-appears but won't run/drip.

I used MLS gaskets and torqued as per OEM order and 3-stepped the torquing. I finished at 45 ft/lb using a brand new torque wrench.

I also had the heads machined and they never were scratched and the block was cleaned w/ a wire wheel that wont score the metal.


My issue is that it's all hunky-dory right now and i am waiting on a fuel pump before the 7psi of boost gets bolted back on. I don't know how much of an impact doing this will have. I have heard these steel gaskets are more "temperamental" than oem. Should I go back and re-torque everything maybe 5-10ft/lb higher to ensure an even seat?? I know my ARP head studs are rated to higher than oem tolerances so can this be done safely?

please add to this if you have run into similar problems, Lexus tech said for 1uz it should be ONLY oem and that steel will give problems.


My gut is telling em that since i have stronger than oem gaskets + head studs whats the harm in torquing higher? Also got mixed feelings about the tightness, and that 45ft/lb is way too low but i heard that over 45 is too high, what gives? I was told by an engine builder that 75ft/lb is what he'd do. I feel like torquing higher and see how it turn's out since i don't have to rip the heads out again. I need some real brains on this one lol.

 

[spf_lexus]

Hah! was just cruising some head gasket threads and it looks like a thread from Lex helped me out. He was looking for the same specs i am, the ARP torque specs and from what he found the 29lb + 90 degree is bogus and it should be done 3 stepped like this:

1st-45lb
2nd-55lb
3rd-70lb

re torque-70lb


Looks like ext week when my new garage is available I plan to tear down to the head studs and retorque them another 20ft lb. makes sense to me... having head studs finished at 40ft/lb and showing sign's of leakage when they should have been finalized at 70ft/lb. Anyone have any input they would like to share? :yup:

 

[stevechumo]

I heard about your problem with the head gasket from David. There might be 2 areas where you may look into. The first area is if the gaskets have been flipped-reversed or upside down before, torqued, removed, and repositioned correctly, and torqued again. The big chance is the gasket surfaces are dented and not sealed, doesn't matter how you retorque the studs. You'll need new gaskets if the coolant is leaked. After awhile, oil will be leaked, too. I never rebuilt this V8, but I've done quite some 4 banger engines so that's how I learned. I believe that's the same concept.

If the above isn't your case, the second area is I'm just surprised why ARP recommends such a low torque. Most engines that I know require an initial tq of 25 ft/lb applied evenly to all studs, then a final 1/4 turn, which is about 90 ft/lb if my memory doesn't betray me. My Lexus manual stated 29 ft/lb for an initial tq, then 1/4 turn. Taking the heads out is a PITA. Sorry to hear about your problem, but once you get it going again, you'll be happy. :fingersx:

 

[spf_lexus]

Thanks for the reply steve, been deciding how next week will go w/ school, garage and parts. I admit, I am NO expert on engines... matter of fact this is the only engine i have ever tore apart. I just saw the look on my dad's face 2 weeks before I needed to be moved out when i said " My head gaskets are toast ". I felt bad since we were out of time and it was going to be $3000 for a shop to hustle on. I decided right then and there that I was going to DO this even if i was working on her the day I leave. And you now what? I really was working on her the day I left. U-haul packed and everything and still no running car... i was a stressed out wreck. I learned the basic must-know tips such as marking cams (and locking scissor gears) ETC and actually she fired up when I gave it 1st try but needed to move timing belt 1 tooth.

As for my "flip-flopepd" gasket... well, thats just me being a noooooob haha. I bought another new gasket from David and decided re-using was not a good idea because i felt the same way. i figured the top layer is stamped, and stamped for a reason and adding a creased line across the whole gasket has got to cause some problems. IDuring the learning process I had more bloody knuckles than i thought possible. It took a whole weekend to take the heads out and by the time I had to do it the 3rd time it was down to half a day. The 1uz is an amazing engine, pretty easy IMO after it's been ripped apart and analyzed.

In the end it took 3 tries and i finally had everything put back and I noticed this "oozing" corner 1 hour before I was scheduled to leave. I threw a bottle of STP coolant sealer in, drover hard for 25min and the leak stopped. 20 min later i had started a 1200 mile straight-shot to colorado.

Steve- thanks for your experience w/ gaskets. I never added the 90 degree turn at the end of the 29ft/lb torque. I just opted for 45ft/lb. I now learned that the 90 degrees constitutes some considerable torque and IMO much higher than 45. I am learning more and more thats just telling me I should have torqued higher.


Any idea of the total estimated torque with 29ft/lb + 90 degrees?

I am planning for the 70ft/lb idea in a few days and from the strength of the bolts/gaskets it can only help?

 

[XR8tt]

By turning 90* you get 100% even torque. No matter the thread..
Sounds to me you havn't torqued them enough...
Being studs ?? With finer thread on top stud. They should pull down hard..

 

[spf_lexus]

Haha such easy mistakes you can make your 1st time! Yeah I just made sure all 10 studs were evenly torqued but i never went past 45ft/lb and thats a fact. No way I added a partial turn after the torquing but I understand why. That 45 degree turn has got to 2x the torque.

Haha I wonder what the odds were to it leaking during a 1200 mile driver through the 105 degree desert w/ only half the head torque!!! haha well I guess I had the "evenly torqued" part right eh? Any less and they would be spewing everywhere like a blown u-boat bulkhead.

Thanks xr8tt-thats what i wanted to hear... re-torquing is much easier than new gaskets.

 

[cjsupra90]

Finer thread gets less pull down per degree of rotation, but is far less likely to back off on its own... An example of this if your familiar with them are the piston and adjuster assembly on a rear brake caliper that has the parking brake built into it.. They use a very course thread this allows the piston to retract easily on its own. The whole point here is that the steeper the thread inclination is, the more likelyhood that the bolted assembly could come undone where as the finer the thread, the less inclination that it has and a greater binding effect that is created and thus less likely it is that it will come undone.... There is a down side though, this binding becomes more and more as the clamp load increases so a small increase in clamp load has a far greater increase in bind and thus a clamp load does not increase as fast as torque, thus requiering more torque to gain a little bit in clamp load... This is why Moly lube is highly recommended and is also what ARP stated a far different toque if using motor oil insted of moly lube.

Here is a chart form ARP with for there standard 8740 alloy studs.

 

[cjsupra90]

Torque w/30-Wt Oil // Torque w/ARP Moly-Lube
1/4in. stud 12-15 // 10-12
5/16in. stud 25-32 // 20-25
3/8in. stud 45-56 // 35-44
7/16in. stud 71-89 // 56-70
1/2in. stud 108-135 // 84-105
9/16in. stud 156-195 // 122-152
5/8in. stud 214-268 // 167-208
6mm stud 10 // 9
8mm stud 25-32 // 20-25
10mm stud 54-68 // 42-53
11mm stud 80-100 // 63-79
12mm stud 97-122 // 77-96

 

[cjsupra90]

Damn-it, if I hit the space bar, it should leave the space!!! Why does the damn server or what ever take it upon itself to remove the spaces that i put in??????????? (Total BS!!!)

 

[spf_lexus]

lol it's all good... maybe more people will see the replies and jump into this one. As far as the moly grease goes I used it on al threads. i didn't "slather" them but made sure they had enough before they started getting grease everywhere. The finer threads are a good thing in my case because I know I torqued them correctly and that in itself held true for the duration of the trip so i got to the 5 yard line but just couldn't get it there. It's seeping coolant basically and so slow at this rate it might take a month or so to even detect a drop in level. I also NEVER get smoke out of the tails and thats good because it should be very white if any coolant was seeping into the chambers so in a nutshell it sounds like it just needs a tighter bond between the metal layers... possibly the stamped upper layer not quite mashed flat?

 

[stevechumo]

....Any idea of the total estimated torque with 29ft/lb + 90 degrees?

You're welcome. I'll try to retorque the head tomorrow or within 1 week and measure it for you. I'll try my best for tomorrow. I also have to change out my engine heads so that's a good coincidence. How soon do you need to know?

Actually, if you could completely take out the engine & tranny as 1 piece, that'll help you a lot quicker to work on it. The turn-around time will be quicker than bending over the car and try to reach to horrible spots such as the exhaust manifolds, rear water bridge..etc.

Or if you're willing to spend an approximately extra $200 to hire a mechanic who can go to your place to just remove the engine and put it back in, you'll save so much time. A good mechanic can move the engine & tranny at once in about 2 hours, plus your free labor...LOL. Pay him $50/hour cash and I'm sure some mechanic will be happy to do it. But make sure he knows about Toyota/Lexus engines. You can leave the tranny intact with the engine and work on the engine. After the engine & tranny are out, you may put them on a set of used tires. Trust me, you'll love how easy it'll get to work like this, and save your backache.

 

[spf_lexus]

I hear ya steve, i need a crane and stand but no bigie. What makes it hard is a have a single car garage and no other mode of transpo. I pln on trying your plan when I decide to buy the 4.7 block, and install will be a simple, in-and-out.

I have been driving this under-torqued engine for about 2000 miles and the leak hasn't gotten any worse which is telling me i evenly torqued, but did not use enough torque to begin with. I get my garage rented tomorrow so I will start, but I plan on just taking off the covers + cams to re-torque. I learned a nice trick from Lex, take one intake cam off at a time while keeping good pressure on the belt, hold the belt tight to the gear as you pull the cam out, and lay it to the side zip-typed tightly to keep tension so you won't skip teeth. i ever need to touch my timing when i redo valvetrain. I plan on just re-torquing to 45ft/lb and then 3-stepping after that to 55ft/lb and then to 65ft/lb and then 70ft/lb. I figure I won't have to rip the heads out.. no real reason, nothing has been tighten where they annot be re-used so i just want to "add" to what i have torque-wise.


Steve- any issues associated w/ taking off the nuts one at a time? ( i have ARP remember ) adding more moly grease to ensure even amount on all the nuts would make me sleep better but I only want to do one at a time so i dont have the whole head loose. basically my evenly torqued studs might loos some of their moly and I want to take 1 nut off, slather the threads and then re-torque that one. Then now that the whole head is torqued properly to the original 45ft/lb i will move to the next opposite olt and do the same thing. Ay issues w/ removing one at a time and re-torquing one at a time?

 

[stevechumo]

..Steve- any issues associated w/ taking off the nuts one at a time? ( i have ARP remember ) adding more moly grease to ensure even amount on all the nuts would make me sleep better but I only want to do one at a time so i dont have the whole head loose. basically my evenly torqued studs might loos some of their moly and I want to take 1 nut off, slather the threads and then re-torque that one. Then now that the whole head is torqued properly to the original 45ft/lb i will move to the next opposite olt and do the same thing. Ay issues w/ removing one at a time and re-torquing one at a time?

Well, I personally don't want to take 1 stud completely out one at a time. I'd do every stud evenly. I never tried to retorque while the studs are still in at 45 ft/lb like you said, but I guess you can try that because the heads are still tight but not loose. The grease or oil is still around the studs when you put it in before so it should still be there. But if you take the studs out, then you should regrease them.

I tried to torque 29 ft/lb initially, then 1/4 turn and guess what, it's around 75 ft/lb. You're very close when you said 70 ft/lb. Good luck.

 

[spf_lexus]

I ended up having to re-do my head gaskets but I never took the studs out of the block... I ended up taking the nut + washer out about 3 times total and I know some of the grease has got to be twisted off the threads so thats why. I want to torque all 10 studs evenly and then after that take a single nut off to add grease and then re-torque that one to match the other 9... see what i mean? Not the stud but the nut/washer above the head. Figure if i take my time and make sure after the nut has been re-greased that it's torqued exactly as i removed it. When i get to the next one i don't have to worry about uneven seat. I haven't tried yet but it's sound from what I can think of.

 

[XR8tt]

The torque is to stretch stud so it acts like a spring when heads expand contract etc.. Yes the studs still need to be tight enough to seal in the first place..
ARP's can be tightened alittle more than OEM engine specs in most cases.. What most people don't realise is these bolts / studs get tightened which "seems" very close to brealing point..

 

[spf_lexus]

XR8tt What are your feelings about finished torque at 70ft/lb? This is 3-stepped using MLS and ARP.

 

[XR8tt]

XR8tt What are your feelings about finished torque at 70ft/lb? This is 3-stepped using MLS and ARP.

70 Lb is much better than 45Lb ..
Keep in mind the studs go into alloy block, the last thing you want to happen is to pull threads in block!!
Atleast with studs the threads are ALL the way into block...
On my Dart Windsor with 1/2 inch ARP's it was torqued to 120 Lb..
It has O ring heads and copper head gaskets for good seal. Tricky to assemble and seal oil, coolant passages..
Double check machining surface ?? It has to be 100% smooth with NO machining grooves.. If there is some on block then some copper spray can be applied.. There is a laquar type sealing agent on [MLS] head gaskets that helps seal..
70 to 80Lb would do the job..

 

[stevechumo]

Sean,

I'm running into the same problem with the leaked head gaskets as you did. I use Cometic MSL head gaskets. Although I torqued everything to 73 ft/lb from the beginning. I didn't check the heads' flatness because I assumed they're flat when they're fairly new. I then had to retorque to about 78 ft/lb. I think the OEM gaskets should seal from the beginning, but the disadvantage are they're not strong enough and not thick.

I'd like to ask a question that how long or distance that your car took to completely burn/vaporize the coolant that was strapped in the engine from the previous leak. Are you still having any leak after re-surfacing the heads and using new gaskets? What gasket are you using now? After 134 miles of driving mildly, my car exhaust still smells some stinky coolant, but its tips are dry. I didn't check for the white smoke coming out of it yet. Thanks.

 

[spf_lexus]

I had my heads resurfaced by a local machine shop and they did my valve job too. I keep wondering if they used the right type of surface texture, MLS neds mirror finish and I never really check before cranking down my studs.

As for my trip I had them tq'ed to 45ft/lb and they lasted 1500 miles w/o a single drop in level but the left side corner would appear "wet" but no visible drip or anything. I get a weird smell too at startup but I can't find any low fluids now at all. I have boosted to redline more than 20x and my coolant level never says low. I keep thinking like you are, that I have residuals in my exhaust but it took a few weeks for me to fully burn all of it out. I was sort of afraid to open her up as I had made a few small mistakes and needed my car!


How many times have you opened her up since the rebuild Steve?

 

[stevechumo]

I just opened the engine up only once after the rebuild. Well, I didn't drive that much after the rebuild. :18:

I just put every thing back this morning and drove for 134 miles. During the driving, I saw some white smoke from the rear view mirror coming from the exhaust tips whenever I stopped at the red lights. But I didn't check for the white smoke again when I got home. I just wiped up the old coolant on the exhaust tips in the mid distance (67 miles) and they're still dry when I got home, which is another 67 miles. It's very hard to determine if the white smoke is regular moisture or the coolant during this winter. All cars have white smoke now in winter.

Before, the coolant leaked so bad that it stayed blue on the exhaust tips.