head loosening

[Uberoo]

real quick question here.When pulling the heads to change the HG is the loosening procedure the same as the tightening order?

IE: 3 1 6

5 2 4

 

thanks.

this is on a 91 EJ22.

[GeneralDisorder]

It really doesn't matter. The tightening sequence is designed to create proper gasket crush. When loosening (and thus changing the gaskets) you can just zip them out with a gun. I do the two center one's first since they are tighter than the outer's. You should be having the heads resurfaced before installation anyway which will true them up.

 

The bolts are VERY tight and have a long unthreaded shaft on them. They tend to not want to come out unless you have a very large gun because the shaft flexes instead of unthreading them. The way to do it is to lower the engine onto an old tire/rim and then use a breaker bar to get them started - if you don't have any engine stand or aren't doing them in a car that is. I've done a set in the car and I wouldn't do that again. It's too tight trying to manuever the heads into place with the gasket hanging on the block and the 8 head bolts flopping around in the head. The driver's side specifically is a pain. The passenger side is easier but still not as smooth and refined as just pulling the engine. Bending over the engine bay is no fun either.

 

GD

[logic23]

x2 on the breakerbar then gun drill to get them the rest of the way out.

Also get a better quality 12pt 14 ive broken a couple cheap ones.

[nipper]

Yes it does make a difference. You could possibly warp the head if you dont do it, besides it is not going to take any extra time to loosen it in order a little at a time untill you feel the bolts have no more pressure on them.

[GeneralDisorder]

Yes it does make a difference. You could possibly warp the head if you dont do it.

 

I dissagree. You would have to loosen them in stages just as in the tightening sequence if that were the case. There is no good way to do that with any degree of accuracy, and warpage of the head would require more movement than is possible - also one only has to note how the heads are still always stuck to the block from gasket adhesion to see that no warpage of any consequence is taking place durring the removal of the head bolts. Otherwise the head would naturally pull away from the block as it warped from improper bolt removal sequence and would just fall off once all the bolts were removed. That is virtually never the case though - you actually have to smack them or sometimes even pry them loose.

 

Besides all that - if you aren't resurfacing them after removal you are doing it wrong anyway. The resurfacing will take out any slight warpage present - which there usually is some anyway with aluminium heads simply from the heating/cooling cycles they go through. It's been my experience that even slightly warped heads will still bolt down and work just fine in most cases - the aluminium being so soft that the bolts will just force it flat anyway.

 

Just not really a swiss watch type of operation here. Best case you wouldn't be able to tell if the bolt removal sequence caused any warpage present since they might have been warped anyway. They usually are no matter what you do.

 

GD

[Fairtax4me]

With heads this size, I wouldn't worry about it too much. If this was a straight 6 then it might be an issue.

Like GD said, If the heads are warped already, then you can't do any harm. And if they aren't warped they were probably on the threshold and probably SHOULD be resurfaced anyway.

[ShawnW]

The factory manual states that you can warp the block not the heads. I personally think it is silly to argue this point.

 

Honestly why not just remove in the sequence they recommend? It takes no more time than doing it in another order.

 

I disagree on the heads needing to be decked every time. Theres a limit to how much you can take off a set and over a span of 2-400,000 miles you could actually need to buy new heads if you decked them at every HG. I clean them with a 3M rubber nub tool with an orbital, check flatness to .003 and deck if they aren't flat.

If they are flat, if you torque factory spec, if you use factory HG, and have everything clean they should last 100,000 or more.

 

I always deck heads with a rebuild or a full valve job but with just cyl HG I wouldn't necessarily always do it.

[Uberoo]

Im taking the heads down to a machine shop tomorrow to check there flatness.I did a preliminary check by setting them down on a granite countertop.one was flat and didn't move at all.the other one wobbled slightly so I will see if its still in spec...

 

one odd thing on this motor is EVERY nut,bolt,etc seems to be on there with a bajillion more ft-lbs than is what is needed.like someone used an impact wrench to tighten everything...

[Uberoo]

I found a nasty surprise on the passenger side block.it seems that the frontmost/upper bolt was broken off some time ago.Its busted off right at the end of the threads so its broken off about 2- 3" in the block.Any chance of a reverse drill bit being able to pull it out?If I cant get the remainder of the bolt out ,can the other bolts be tightened just a touch more to help seal that corner?

Edited August 9, 2010 by Uberoo

[Fairtax4me]

You'll have to drill it out. Drill it out, tap it, and use a thread repair kit so you can put a new bolt in there. If you try to tighten the others to compensate it will warp the head and the seal will fail if it works at all.

[Uberoo]

The passenger head was warped .008" and the driver's head was warped .006".Subaru spec calls for .002".Im just wondering if in the real world that little bit matters.I know that the bolts will flatten down the head to an extent,and the head gasket itself can take up some.I'm just asking because the machine shop wants $90 to mill them flat.After buying the car for 120 and the HG/intake manifold gaskets for 70 im flat out broke.

 

Ive heard of using a glass plate and some some sandpaper to "mill" it flat,but I don't know how long it would take to take off .008" and .006" respectively.

[GeneralDisorder]

How are you measureing that? If you aren't useing a machinists straight edge then you can't trust your measurements. I've run into this before - things we take for being "flat and straight" in normal daily life are almost never actually flat enough. A metal ruler or square is not even close. I've seen them warped .010" and that will throw off any measurements enough that they can't be used.

 

GD

[Uberoo]

machinist layed a metal bar "straight edge" over the heads and measured it with a feeler gauge.then I balked at the price.

[GeneralDisorder]

machinist layed a metal bar "straight edge" over the heads and measured it with a feeler gauge.then I balked at the price.

 

Ah I see. What was the price? I pay $40 a head for resurfacing. Used to be $35 but it's gone up with the poor economy.

 

I've done the glass and paper bit and it's not horrible - tricky and takes hours but it's doable. 8 thou would come off pretty quick most likely. You just go till there aren't any low spots left. 120 grit is a good starting point and then finish with 180. WD-40 is used as a cutting fluid and to clean the paper - it's important that you use the WD-40 to clean the paper or you will damage the paper. Use wet-dry paper of course.

 

It's a budget thing - I don't do it because it's time consuming. But I have done it. Recently I did it on an EA82 because it was Sunday and my friend didn't have the coin to pay the shop anyway. He's a special case though and has helped me a ton with stuff so I return the favor when I can. It's not something I would do on any of my paying jobs though as it's not cost effective unless you are just dirt poor

 

GD

[Uberoo]

$90 to do both,but I AM dirt poor.

 

why would it go UP with bad economy?then more people can't afford it and will do alternatives..

 

How to make the wet/dry stick to glass plate?What to use to find high/low spots?

[GeneralDisorder]

Less business overall is really the reason. People don't have jobs so aren't fixing things or are only doing the bare essentials (instead of an $80 valve job/resurfance they will only do the $40 resurface). Also these guys do a lot of race engines, port&polish, etc. That stuff isn't being done because there's no one with the expendable income. So they have to increase the prices of the jobs that people can't do without even in a bad economy to offset the other work they aren't getting.

 

You'll be able to see the low spots as you go. Just wipe off the head and visually look for places where there is still gasket material or the metal isn't shiny and there are not sanding marks.

 

You can use spray adhesive to keep the paper on the glass, or you can cut the glass in such a way that you can bend the paper over the edges and hold it that way. Depends on if you want to move the glass/paper across the head or move the head across the glass/paper. Both can work but typically it is better to leave the glass/paper stationary and let the weight of the head insure the sanding process proceedes evenly.

 

The ideal process would be to have a sheet of paper that was 2' x 2' and adheared to the glass with a very thin layer of spray adhesive. Then you could run the head over the surface in a figure-8 pattern.

 

You have to use THICK glass to insure there is no flexing and back it up with thick plywood, etc. I wouldn't use any less than 3/8" thick glass and 1/2" would be better.

 

But by the time you buy all the materials you would probably be pretty close to paying the shop. Call around and see if you can find a better price. Like I said I pay $80 for two heads and I know there are places that are cheaper. I had a friend that found a place that did his for $25 a head. I wasn't impressed with the surface finish but it worked fine. These aren't swiss watches and often I am too picky about that sort of thing.

 

GD

[Uberoo]

how about some thinish glass on top of a granite counter top?

[GeneralDisorder]

You can try it . I've seen crazier things.

 

GD

[Uberoo]

I wonder if spray copper coat would be a good thing to use?

[GeneralDisorder]

No - always install the HG's dry with clean, oil free surfaces. You should clean the surfaces with an evaporating degreaser. I use Laquor Thinner personally.

 

GD

[Fairtax4me]

I wonder if spray copper coat would be a good thing to use?

 

That stuff works great on head gaskets for about ten minutes. Then it burns out and blows away, and leaves you with a huge mess on the heads and block. And that stuff's no fun to clean off. I've watched that happen more than once. Even after being told exactly what would happen the doofus' still did it, and had to replace their gaskets a second time.

 

Clean and dry like GD said.

[Uberoo]

As far as the bolt goes will 7/16 fine thread hold?I was thinking drilling the bolt out down to original thread depth, then re tapping it for 7/16 fine thread.Then find a long bolt.Will grade 5 hold or grade 8 be better?

Edited August 10, 2010 by Uberoo

[Fairtax4me]

I really couldn't say one way or another. I don't know much about bolt strengths, but I'm pretty sure grade 5 will be too weak for a head bolt.

I'd strongly suggest drilling the whole thing out and retapping for a real replacement Subaru head bolt.

[Fuzpile]

Ubaroo. The odd bolt (7/16x20 0r x22?) is going to be harder to find than the Subie bolt and will react different to the heating. Some may wonder if its breakage caused some of this tbl. The setup for drilling out is important in alignment. A plate or bushing so the pilot size goes absolutely straight. Then at a larger size a LH bit can be employed and sometimes the old thread core will wind out without cutting into the threads.

[GeneralDisorder]

DO NOT change the bolt to a larger size. This will throw off the torque value and make it near impossible to properly install the heads. Besides that as mentioned if you don't know the proper composition (grade) of the bolt you shouldn't be messing with it. That is way beyond your pay grade .

 

Heli-coil it.

 

GD