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Questions on HG's


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For starters, I am going to be replacing my intake manifold gaskets on my 92 SPFI Loyale PB 4x4. I have a known coolant leak there which is causing annoying isssues. Since I am also having subtle symptoms of HG issues, I was considering changing those at the same time along with valve cover gaskets. My symptoms are immediate pressure in coolant reservoir, disappearing coolant, rough idle, a very small (hardly noticeable) amount of oil in coolant and milkshake under oil fill cap (oil still looks brand new after 1000 miles though). So I should probably do a compression test to find out for sure, but I really don't want to have to take the intake stuff off and fix that to find out later that I have to do it again plus HG's. I also feel that it would almost be better to just do them since I will have done just about every other seal on the car. What do you think? I have never done HG's before, but I think it would be fun just to learn. I do not plan on taking the engine out to do it nor do I plan on resurfacing the heads. Any pointers on how to do this are much appreciated. I believe in learn by doing and sometimes that is the hard way, but he who learns from his mistakes is a wise man.:rolleyes:

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You can do the HG's in the car, it's not that bad. The trickiest part is getting the lifters to stay in place while you mate the cam carrier to the head during installation. They fall off because there isn't much holding them on. If you are going to try it with the engine in the car, assembly lube works pretty good to hold them in place. You can jack one side of the car up (the side that you are working on) so the lifters can 'rest' instead of 'hang' in place. Alternately you can easily undo the two motor mounts, and the two tranny mounts (all 4 are 14mm) and jack the engine up bit to get more clearance if you like (watch the O2 sensor wire if you do). Make sure to clean off the heads and block really well. A nice wire brush, maybe a couple of them with some acetone (or solovent of choice) works good to get the little pieces.

 

Other tips...

 

- Make sure you have a reliable torque wrench.

- Clean the bolt holes.

- Check all of the bolt torque specs so you don't over tighten and break any bolts.

- Clean and oil the head bolts before they go back in (wire wheel on a drill works nice here).

- Felpro permatorque gaskets work nicely and only need to be torqued once to about 5-10 ft/lbs over spec.

- Use permatex ultra-grey for cam carrier to head sealant.

- When reinstalling the cams turn them so the timing hole on the sprockets go to 12 o-clock - that way the cam is in a neutral position, and you will be able to put the cams back on without scattering your lifters.

- Might as well do the cam seals since the heads are off (on that note a valve job now could also be to your benefit).

- New cam carrier o-rings are a must - part number 13089AA010 from the dealer for about 2 bucks each or so. You will need two.

- Depending on the last time you did your exhaust gaskets you might want to replace them as well since the pipes are coming off.

- Timing belts are coming off...how are yours lookin?

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I just did the water pump, camshaft seals and o-rings, crankshaft seals, oil pump seals, and timing belt kit about a month ago. I think I may have done something else too, but I can't remember...it wasn't anything big. Thanks for the awesome info. A valve job? what's that? Are there any procedures for head gasket replacement on here? Miles, do you have anything like one of those videos?

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Today I tried an old trick to recognise left or right head gasket is blown. Gave 6 bar pressure from a garage compressor in cylinder thru spark plugs hole when piston is in TDC and both valves closed. Then turned next cyl. and next. To hold crankshaft from rotating under pressure put into 1st gear. There were bubbles in radiator doing this job with cyl #1.

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  • 2 weeks later...

hey I'm going to bump this up. I got some great info here, but I am still not sure about the whole valve thing. Will it be too much of an issue for me to just slap (properly, not a crap job) the head gaskets on and call it good? I assume there is a possibility that low compression could be due to the valves, but it it really that important to do?

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valves are not likely. Put on the head gaskets and go!

 

I have done ountless HG's with no machining. I will use razor blades and brass wire to clean, sometimes some wet sandpaper for carbon deposits.

 

Subaru heads are not too picky to install(my opinion), and it is also of my opinion that machining them down will make them not seat the same, as the heads should probably be machined on a toque plate. The heads have a little bit of concavity with no torque on them.

 

You would have to cook your engine a lot harder to warrant any machining.

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do I need new head bolts? I know they are generally recommended. Also since this is my first time, what should I expect with the cams and lifters, etc? It sounds like they can easily make this job a PITA. Oh, and valve stem seals?? I feel like i waqnt to replace these since I am in there already..opinions? Any tips other than noting positions and using assembly grease for reassembly?

Edited by The FNG
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Nope no need for new headbolts, just reuse them. A few people on here will tell me thats a stupid idea BUT this isn't a turbo'd car and it appears to be totally stock. So reuse them, torque them down through the proper procedure and call it a day. I'm in the process of doing a complete reseal on my XT6 and the only thing I had done to the heads were milled flat as the driver side was a hair out of spec.

 

Clean off the headgasket surfaces real good on both the heads and block, then use a straight edge and a .002" feeler gauge to check the heads for warping. I had to have .0035" and .0065" taken off of my heads.

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do I need new head bolts? I know they are generally recommended. Also since this is my first time, what should I expect with the cams and lifters, etc? It sounds like they can easily make this job a PITA. Oh, and valve stem seals?? I feel like i waqnt to replace these since I am in there already..opinions? Any tips other than noting positions and using assembly grease for reassembly?

 

Nope. These are not stretch bolts in iron blocks. usually the valve stem seals come with an upper end rebuild gasket set. YOu would have to reomove the valve keepers and use some valve lapping paste since you have it apart.

 

i usually forgo the valve stem seals as i am not trying to do that much labor/if the work is not needed/mileage

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  • 3 weeks later...

So I have not had time to work on the car for a while, but I finally got around to doing a compression test. I got the engine hot, pulled the plugs, pulled the fuel pump fuse, propped the throttle open, and cycled the engine at least 4 times if not more. These are the results I got (Correct me if I'm wrong, but cylinder 1 is passenger side front, 3 is passenger side rear, 2 is driver side front, and 4 is driver side rear):

 

1)130

3)110

2)120

4)120

 

My gauge does not have a detailed scale, so these are close, but not exact. I know the numbers are supposed to be within 10% of each other, but how is this defined? Also, are these numbers acceptable? Cylinder 3 seems low, but I really don't know. I'm hoping these numbers tell me I don't have a head gasket issue. Just want to make sure before I start to work on the car this weekend.

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