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Old 11-16-2008, 04:27 PM   #21
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My experience coming from the supra world where the 7m's have notorious hg blowing problems, i have to say that it might be the block. every supra that i have done a HG job on with a mhg HAD to get the block machined as well. I am not too sure if you guys ever had composite style gaskets or not, but i guarantee if you used one, it wouldn't leak if the problem was the block itself.
Now coming to your other problematic post with the bracket, that could very well be the cause. The supra timing covers need to be machined with the head or else, just like what you are considering, stay up just ever so much, and back to a BHG again.
Also, if you want to use copper spray, make sure you remove all viton coating on the stock gasket or it will leak as well because the chemicals will react with each other and cause an improper seal.
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Old 11-16-2008, 09:15 PM   #22
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I forgot all about this thread. I attempted a clean start again last weekend, and got another smoke bomb. This time it was coolant from what I could tell. When it first started it was oil smoke, but after about 2 or 3 minutes of idle, the oil smoke went away (which may have just been some of the copper coating burning off, which I wont try to use again) and the coolant smoke started. It runs and I can sort of drive it, though I havent been, but it bogs if I cruise and then give it a little throttle.

I decided last week that if I can find a 99-00 JDM engine I will go that route, just to get it back on the road, since I wanted the 99-00 head anyway, plus a bit more pep with higher compression ratio. If I dont find one soon, I have a set of Mahle/Clevite bearings and rings on the way, and I will bring the block to be machined, have the head checked over once more, redo it all again and hopefully this time have the problem fixed. I havent yet checked the block with a true flat edge, so it very well may be the block, though I cant see how with it being iron. It may be some of my doing, I cleaned the block off with a wire wheel, but I didnt think a brass wheel would take off enough to matter. I guess maximum warp on most 4 cylinder iron blocks with aluminum heads that use MLS gaskets is only like .002 over the full length, or .001 over any given 1'' (I think thats correct anyway). So maybe my wire wheel did take off enough to matter.

This time I WILL NOT cheap out or rush. It took me 3 times to learn this, but I just assumed too many things. Block will be machined, head checked to be 100% sure its still flat and not crooked/out of square from the first machine job. WHile Im pulling the block again, no point in not doing bearings and rings. I also meant to drill and tap the oil pan for near future turbo install, but couldnt find the tap in time and wanted the car running again, so I left it alone. Alot of little things I can take care of this time. I also had some throw out bearing noise that had me wondering. New clutch, flywheel, pilot bearing and throw out bearing, but for some reason it had that usual rattle with the clutch up, when I would rev and let off it would rattle as the rpm's began to drop. I have the increased gear noise from the light weight flywheel, but thats not the same noise.
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Old 11-16-2008, 10:46 PM   #23
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Collectively, how many times have you removed the head and changed the head gasket without checking to see if the deck is warped? And please, tell me why "I cant see how with it being iron".
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Old 11-17-2008, 12:01 AM   #24
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Quote:
Originally Posted by patsmx5 View Post
Collectively, how many times have you removed the head and changed the head gasket without checking to see if the deck is warped? And please, tell me why "I cant see how with it being iron".
Ive lost count actually. 3 I think, this next assembly will be the 4th time. I checked the deck this last time with my straight edge, which isnt a machine shop straight edge, and only saw .001-.002 in some spots, which I passed off as being my straight edge. Why I cant see it being the block is because you rarely or never hear people talk about warped iron blocks. Thats not saying it cant happen, but I just figured with so little talk about warped blocks, how could mine be warped. I know thats not the right thing to do and think when rebuilding an engine, but I learned from it. Wont happen this time for sure. Which is why its being machined. I couldnt find a shop to loan me a straight edge, and if Im going to bring the block to the shop, it may as well be machined wether in spec or not.

It just doesnt make sense to me that a substantial chunk of iron could warp, especially with it having an aluminum head bolted to it. If it were going to warp, surely the head would go long before the block.

Yes I know, shame on me, I should have my wrenches taken away for being stupid so many times. Im still not even sure its the block, but it is the only thing left really. I also havent checked the head for square, but Im not sure that a .010 or less drop on one side would make it crooked enough to not seal. If it is crooked though, it will be fixed, either by remachining it, or by purchasing a 99-00 head.
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Old 11-17-2008, 08:19 AM   #25
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when the aluminum is overheated, the metal properties of aluminum will twist, and therefore lifting up one side of the head. When this happens, it pulls the hot cast iron block with it. Although it is stronger it shall still warp.
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Old 12-28-2008, 10:40 PM   #26
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This is the third post I have seen on this issue but nobody has found the solution. I have pretty much the same problem and I can't figure it out either. The car is a 94 1.8L with approx 110K on the clock. The car started to smoke this past summer but would quit after a few min running. The oils stayed clean so I did not think much of it till last month when it started to smoke all the time. The oil was still fine and clean, no signs of water mixing in it. I did a compression test and all cylinders were around 185. The cylinder leak down test revieled that cylinder 3 had the coolant leak as I could hear the pressure loss thru the radiator. The rest of the cylinders appeared to be fine. Off came the head. I pulled the head with both manifolds on. I could not tell where the leak was as the head came off a few weeks it ran last. I cleaned up both surfaces and did not see anything wrong. No cracks that were visible. The gasket surface checked out ok with my straight edge. I put the head on and did a cylinder leak test on all the cylinders. Everything appeared to be good as all were around 20-30%. I put the rest of the engine together and the car still smokes. I let it run for over an hour in the driveway hoping that there was still residual coolant in the exhaust and CAT. The smoke did not appear to get better. Back in the garage, I did another cylinder leak down test. When I pulled the plugs, there was steam coming out of cylinders 2 and 3. The valves were open on 2 and 3 when the plugs were pulled. The cylinder leak down test was the same after the hour run. All cylinders were around 20-30% leakage which is supposedly good. I then pressureized the radiator to 15 PSI and found a leak due to a loose hose clamp at the Throttle body. After tightening the clamp some more I pressured the radiatior again and it lost about 2 PSI in about 10 min.

I am at a loss here.... Since the cylinder leak down test was good, I have to believe the headgasket is sealed. There could be a crack but why is the cooling system holding pressure?

Are there any coolant ports in the intake manifold?

There was a thread on this site where someone replaced a throttle body and the engine started to pour out white smoke. I think I may check mine.
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Old 12-28-2008, 11:19 PM   #27
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Sorry to hear your having the same problems I was having. I still havent found my problem for sure, but Im hoping this rebuild has fixed it. There is a thing on the bottom of the throttle body that has coolant passing through it, with a gasket. It could cause a coolant leak into the intake manifold. Have you run it and shut off the car and looked through the t/b to see if any coolant is left standing in the plenum from the hole in the floor that goes to the thing that for some reason escapes my mind right now.
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Old 12-29-2008, 01:01 PM   #28
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FYI - It is very common to "deck" a block to ensure trueness. Ask any machine shop.

Iron blocks are under mechanical stress from the moment the casting is poured. Repeated heating and cooling from 100k+ miles of use will sometimes cause the casting to "relax" a bit from when it was first machined as a fresh casting.

Castings have a granular structure created as iron flows into the mold (much lile a piece of lumber has a ring structure) which can add resiliancy in one direction more than another.

Also think about the differences in thickness of the various parts of the top of the block. Different thicknesses being heated the same amount will expand differentialy. This is why we must cut the flanges on the cast iron turbo manifolds (yes, that is a more extreme heating and cooling, but the principle is transferrable). Notice that the little cut in the manifold flange becomes larger or less uniform (twists slightly) after several heat cyclings. This is why a "seasoned" block is often decked or at least checked for true.

All of this being said, your block may be just fine. Did you account for the fact that decking the head means that the head bolts plunge deeper into the block? They might be tightening to where they had stopped for the previous 100k miles and no further. Always chase the threads with a tap and clean shavings, debris, and gasket scrapings out of the bottoms of the holes.

Additionally, if you believe the resurfacing that was done might not be square, have another machine shop measure it. Taking off .015 is a but much to get it true unless it was really far out. And machine shops have trouble finding good help just like everybody else.
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Old 01-01-2009, 02:35 AM   #29
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Yeah, this was taken care of a while ago. Im starting to think now after seeing how my rings looked that my head gasket may have been fine the last 3 times. The first time it was probably from the staple stuck between the head gasket layers. The last 3 times it was oil smoke, and I found all 4 of my oil control rings stuck in their grooves. Still cant understand how this would cause the car to run rough and try to die under load, but I guess with all 4 rings stuck, thats a pretty nice 1.8L oil pump.

The block deck was machined true, and the head will be going back to the machine shop either friday or this weekend to have one of the dowels pulled, and another few thousandths taken off to remove some minor scratches that are bugging me. Should be no excuse for a gasket leak now. Bolts still have 5 or 6 full turns before they bottom out, so thats not an issue.
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Old 01-01-2009, 02:44 AM   #30
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I recommend getting some new bolts/studs. I had phantom HG leak problems that took me a year to diagnose. Turned out that the head bolts were stretching. I put in ARP studs and haven't had a problem for 3 years and 50K miles with a cheap ebay HG.
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Old 01-01-2009, 02:54 AM   #31
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Anybody know the factory bolt length? I dont quite grasp how a stretched bolt would cause a loss of torque though, unless its stretched enough to be weakened and stretches each time its torqued. Mine, as far as I know, are original, and the head was never pulled before I pulled it. Never really heard of anyone having issues with the bolts. Not saying that wasnt your problem, or its not possible. Id hate to pony up for studs this far into the "build", and on a stock bottom end. But at the cost of new bolts, if I did need new ones, studs would probably even be cheaper. Actually, wonder what bolts go for?
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Old 01-01-2009, 02:57 AM   #32
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it was much cheaper to get studs than bolts last I looked. it's apparently a fairly common problem amongst people who swap heads regularly (spec miata, etc).
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Old 01-01-2009, 03:00 AM   #33
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Damn you, now you have me worried again. I was so sure, now I doubt. Hmm, I see some ARP's for $125... just have to wait probably a damn week on them.
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Old 01-01-2009, 08:30 PM   #34
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arp for everything is a standard rule in engine modification.
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Old 01-03-2009, 03:37 PM   #35
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Son of a bitch. Well, now that you guys have thoroughly scared me, Im going to be ordering some studs. I just know this is going to turn into one of those deals where the studs end up being a special order item and take 3 weeks to get here, when I will be ready to bolt the head back onto the block Tuesday. Anybody recommend any certain place to order from? I was looking at Alamo in east florida, since thats not too far from me, and they have a good price at $120, vs FLyin Miata at $170. Id guess Flyin Miata would be more likely to have some in stock, but I cant pay $50 for that.
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Old 01-03-2009, 10:02 PM   #36
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Last I checked the factory bolts are about ten dollars each. The head shop told me the Mazda factory bolts were good for 3 R&R. At this point I'd replace them with ARP. And check the head and block, and install a new HG, and do a visual inspection for staples.
No actually I would have put another motor in 2 head removals ago. Thats why I have 1car and 3 motors. Good luck.
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Old 01-03-2009, 11:35 PM   #37
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just don't order them from Titan racing... those ******* gave me the run around for 6 weeks before I finally canceled my order and bought from FM.
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Old 01-04-2009, 12:25 AM   #38
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****, Ill just order from FM, though more $, at least maybe they will have some in stock for immediate ship out. Still probably end up having to wait on them since my other stuff will be ready mid next week. Oh well, what can you do.

How "reusable" are the ARP's? Im guessing you can get quite a few uses out of them as far as removing and re-torquing.

EDIT:

$194, that wasnt too bad, and with 2 day shipping. Maybe they will process it first thing Monday and it will get here before friday.
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