Head gasket replacement ?

I have a roundtoit project sneaking up on me. 89 Renix, 4.0 head gasket job. I already have the entire gasket kit, but I wondering what studs and nuts, if any, I should replace on the head or manifolds? Also does anyone have the length and thread specs handy on any that I should replace no matter how OK they look?

Do I need any special tools for the head removal if I am leaving the valves intact? I am only replacing the head gasket, not doing any valve or head work.

I may have some more questions after I re-read the haynes how to section on this.

Ecomike said:

I have a roundtoit project sneaking up on me. 89 Renix, 4.0 head gasket job. I already have the entire gasket kit, but I wondering what studs and nuts, if any, I should replace on the head or manifolds? Also does anyone have the length and thread specs handy on any that I should replace no matter how OK they look?

Do I need any special tools for the head removal if I am leaving the valves intact? I am only replacing the head gasket, not doing any valve or head work.

I may have some more questions after I re-read the haynes how to section on this.

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Check your head screws - if they have paint marks on them, you need new ones. OEM head screws are a modified TTY, and are good for two torque cycles.

Manifold screws and nuts should be replaced - I prefer silicon bronze, but any copper alloy should work. If you can't get that, use SAE5 (SAE8 is more sensitive to heat cycling.) Studs for that can be cut from 3/8"-16 threaded rod.

Manifold collector nuts should be replace with brass - makes it easier on you.

Thermostat housing screws should be replaced with brass or CRES.

Sizes should be listed for most of this stuff on my site - if you replace something I don't have listed, please let me know so I can add it.

i'm in the middle of this right now, literally since i'm to the point of putting the gasket in and replacing the head. anyway, i read that if the bolts aren't already painted then they are okay for another use, but you should paint them so they aren't used again. some folks will argue that you should replace them anyway and maybe they're right.

you won't need any "special tools" but a complete set of drivers and sockets plus extensions and a universal were necessary.

i hear that it's common to snap manifold bolts, but i only broke one, which I will have to get removed. the rest were just hand tight, yikes!

even though the haynes is pretty thorough, i recommend writing down everything you do, because there's so many little things that you need to remember when you put it back together.

All i needed that i didnt have was a torque wrench that went to 110 ft #'s. I just borrowed one from a buddy.

There is alot of info on the subject in the thread below:

http://www.naxja.org/forum/showthread.php?t=933960

OK, so I need to remove the head bolts, loosening them in the proper sequence, and remove the manifold bolts, and probably anything that gets in the way of reaching manifold bolts.

But since I am only doing the head gasket (I think) do I need to do anything with the valve train? Do I need to remove the rocker arms, and push rods at least? How far do I need to go for a head gasket replacement only?

Ecomike said:

OK, so I need to remove the head bolts, loosening them in the proper sequence, and remove the manifold bolts, and probably anything that gets in the way of reaching manifold bolts.

But since I am only doing the head gasket (I think) do I need to do anything with the valve train? Do I need to remove the rocker arms, and push rods at least? How far do I need to go for a head gasket replacement only?

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Removing the rockers will allow you to pull pushrods - which is easier than having them fall in (or fall out!) of the engine when you lift the head off. All parts can be reused without incident, just be sure to keep them in the proper order (not as critical as cam/lifter relationship, but why buy trouble when you get enough for free?)

I find it easier to remove the head and manifolds as a unit and service the manifold gasket on the bench, but I'm a good-size fella. Either way, having a 9/16" "flex" socket won't go amiss...

I like to use non-ferrous screws for the manifold and for the thermostat housing. CRES can be used for the thermostat, but I like Si-bronze for the manifold setup (they won't seize on the iron like ferrous screws do.)

Check torque on the manifold screws about once a year - you'll fine one or two loose. This is due to the fact that they're clamping both iron/steel and aluminum - recall that aluminum expands twice as much as iron due to heat. Loctite #272 or nothing on manifold screws.

Yes, you can reuse head screws once. I've had to go burn out screws for people who tried to use them twice (intentionally or no.) Put paint marks on the heads after they're in - or just replace them outright and not worry about it. Torque in stages (50/75/110 pound-feet works well,) with the driver's side front screw getting PTFE paste and torqued to 100 pound-feet.

The manifold collector stud nuts are 3/8"-16 - replace them with brass. Sam reason as Si-bronze screws on the manifold-to-head join.

Ecomike said:

OK, so I need to remove the head bolts, loosening them in the proper sequence, and remove the manifold bolts, and probably anything that gets in the way of reaching manifold bolts.

But since I am only doing the head gasket (I think) do I need to do anything with the valve train? Do I need to remove the rocker arms, and push rods at least? How far do I need to go for a head gasket replacement only?

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Are you not planing on removing the head with the exhaust and intake manifolds still attached? I would recommend doing it this way as its way way easier to get to, and get the proper torque on those intake/exhaust nuts and bolts.

Here is a basic "write-up" on how to remove the head.

Disconnect everything from the head, intake, and exhaust manifolds that will prevent it from being removed. Remove all the wiring from on top the intake manifold (to the injectors, TPS, IAC, Knock Sensor, 02 Sensor, CTS etc) and move them to the side along the firewall. Use a zip tie to hold it if it wont stay. Disconnect the supply and return lines to the fuel rail. Disconnect the top two bolts for the AC bracket. They should be pretty obvious to see as they are the only ones that go to the head. Look around and imagine that your pulling this head straight up into the air. Is anything going to prevent you from doing this? (wires bolts etc) If so remove them and move them out of the way.

Remove the valve cover.

Remove the rocker's and associated hardware (bridges etc) Set them down on something that will be out of the way and keep them EXACTLY in the order that you removed them. This will aid you in putting them back in the same place where you took each of them off.

Pull out the pushrods. Do the same thing as you did to the rockers. Keep them in something that will aid you in putting them back in the same place. I have found a long peice of cardboard (idealy a shoebox) works well for this.

Remove the head bolts. You shouldnt have to remove them in any particular order. Just unbolt them and remove them. (remembering where they went of course). Check for paint marks .. if painted they have already been re-used once and need to be replaced (TTY bolts)

The head is now ready for removal. I just picked it up and slid it out of the engine bay, but im sure you will find a way that works for you.

Start cleaning. Clean clean clean. (remove gasket material sludge buildup etc)

If you want to replace the intake and exhaust manifold gasket... (you should).. Remove the intake and exhaust manifolds from the head now that its removed. Clean clean clean some more.

Re-assemble the intake and exhaust manifolds to the head with a new gasket. I used copper silicone around the exhaust and intake ports (on each side of the gasket). I would also recommend this. Use your FSM for this procedure. (torque and sequence). Also, if your not replacing the studs, or if you are and you are using peices of threaded rod (instead of OEM) use head bolts as a "stop" for the rod, as the studs in these locations end up going into where the head bolts should be. If you put the head bolts into these three locations as a sort of "stop" then when tight, they will not interfer with your head bolts when it comes time to install them.

Cut 4 3" peices out of your 3/8 x 16 threaded rod. Cut a notch at one end of these peices that you can use a standard screwdriver to turn. Use these peices as "dowels" to help you to line up the head, and head gasket to the block. I put my "rods" at the two spots at the front of the block, and the two spots almost at the other end of the block. I made sure about 1 1/2 to 2" of the 3" rod was protruding from the top of the block.
Put the head gasket on, and then get ready to put the head (that now have the intake/ exhaust manifolds attached and torqued correctly) back onto the block. I had a helper, and it took some time to heef that heavy crap into the right position. If you have a hoist, that will help extremely.

Once you have the head on the block, you can remove the stud "dowels" that we used to line everything up with a standard screwdriver. Once they are loose, you use a magnetic pick up tool to retreive them from the head bolt holes.

Now re-assembly should be fairly straightfoward and easy. Follow the FSM procedure for torque sequence and toraue amount. IIRC, the head bolt that drops down into the water jacket above the water pump does not get tightened as much. It also needs some high temperature thread sealant.

I hope all this information helps.

@Muad-Dib - Correct, save that you'll cut manifold studs from 3/8"-16 threaded rod. Use 1/2"-13 for the alignment pins on the cylinder head - 3/8"-16 will just fall through the hole (may as well use old pushrods for that. I have, from time to time...)

5-90 said:

@Muad-Dib - Correct, save that you'll cut manifold studs from 3/8"-16 threaded rod. Use 1/2"-13 for the alignment pins on the cylinder head - 3/8"-16 will just fall through the hole (may as well use old pushrods for that. I have, from time to time...)

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Yes thank you .. i must have been typing too fast and said 3/8 x 16 when i meant 1/2 -13. Thanks again.

Muad'Dib said:

Yes thank you .. i must have been typing too fast and said 3/8 x 16 when i meant 1/2 -13. Thanks again.

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No worries - but I've got to correct you one more time. You damn sure do have to remove the head screws in a particular order - at least, to break torque on them! Standing on the driver's side, you start with the passenger rear of the head and work in an anticlockwise spiral.

If there is a torquing order to installing the screws, you need to break torque on them in the reverse of that order... Warped heads suck.

Hmm .. i didnt do that maybe i was lucky!

5-90 said:

No worries - but I've got to correct you one more time. You damn sure do have to remove the head screws in a particular order - at least, to break torque on them! Standing on the driver's side, you start with the passenger rear of the head and work in an anticlockwise spiral.

If there is a torquing order to installing the screws, you need to break torque on them in the reverse of that order... Warped heads suck.

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It sounds contradictory up above, i.e. the spiral anticlockwise. Haynes and the FSM show a torque sequence and IIRC from reading 2 weeks ago, one of them says to do the reverse of the torquing sequence for loosening and removing the head bolts. Did I miss something, maybe the spiral term is confusing me?

Never mind, I just rechecked and it was the 4 banger I was looking at, page 2C-6 of my edition of Haynes (by the way, we recently discovered variations in the Haynes books year to year, different copywrite dates for the same book), shows a nice picture of the opening spiral for tightening the head bolts, so your right on with the anticlockwise spiral ( I just missed it before somehow), just hard to picture from the words. Haynes does say the last bolt is the rear drivers side, so it seems the rear drivers side bolt should be first, not the passenger side. For anyone who is having trouble picturing this it starts as a large spiral from the outside and winds its way in slowly to the center bolts, the reverse of the clockwise spiral for tightening new bolts.

I am planning to pull just the head. Is that a mistake???

I will be doing this one in my driveway, no hoist or lift.

I was hoping to leave the rockers alone, guess 5-90 does not think much of that idea, sounds like he is mentioning hard knocks lessons from trying that himself? :laugh3: Something about droppping push rods somewhere, LOL.

Ecomike said:

I am planning to pull just the head. Is that a mistake???

I will be doing this one in my driveway, no hoist or lift.

I was hoping to leave the rockers alone, guess 5-90 does not think much of that idea, sounds like he is mentioning hard knocks lessons from trying that himself? :laugh3: Something about droppping push rods somewhere, LOL.

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I just like to be thorough and put things back where I found them (if I'm going to reuse them - even if it's not critical that I do so.) I don't think you can really drop the pushrods down into the sump - but I've not looked at that area in a bit, so the drainback holes may be large enough to allow it.

Ideally, I'll dig out my drilled wooden block (it's got holes for pushrod sorting, lifter sorting, and rocker arm/bridge/pivot/screw sorting) and put the pushrods in it. The rockers, bridges, and suchlike go back into the head, finger-tight. That way, I don't have any loose bits to worry about.

When I put it back together, I'll also trot out the assembly lube and put a generous dollop on the underside of the rocker pivots when I put them all back together, just to save trouble (I don't think the FSM sez to do so, but it certainly won't harm anything. Never has. Probably never will.) Assembly lube is oil-soluble, so it will rinse out and drain with the oil change anyhow.

For cleaning gasket residue, I find that the Scotch-Brite Roloc wheels (or similar) work best - they'll strip the old crud right off, not remove any metal, and will leave the "slightly rough" finish that encourages head gasket sealing. Use a "medium" abrasive grade or finer. (I'll use brass wire wheels just about everywhere else, but Scotch-Brite gets used on the deck and manifold surfaces.) A Nylon "bristle wheel" impregnated with fine or extra fine abrasive works neatly for cleaning piston heads and combustion chambers, if you want to give them a touch (make sure the pistons are at TDC before you clean them using power tools, so you don't score the bore. Use light pressure. Rinse with carburettor cleaner to blow out all the loose crud after you're done, before you move the piston down.)

Removing/replacing the rocker arms is largely trivial - there is no installation adjustment (torque to 19-21 pound-feet, and you're done) as there is on, say, SBChevvy or SBFord engines. A bit of assembly lube on both ends of the pushrod and on the rocker tip/valve tip won't go amiss, either.

(Can you tell I haven't had to concentrate on this job in a while? I keep thinking of stuff I did last time, but hadn't mentioned before...:twak: :twak: :twak: )

Ecomike said:

I am planning to pull just the head. Is that a mistake???

I will be doing this one in my driveway, no hoist or lift.

I was hoping to leave the rockers alone, guess 5-90 does not think much of that idea, sounds like he is mentioning hard knocks lessons from trying that himself? :laugh3: Something about droppping push rods somewhere, LOL.

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I did it in my friends garage without a hoist or lift... but i DID have his help. You should be able to remove the head as an assembly with the manifolds attached by yourself. Getting it all back on correctly by yourself is a different story. If i didnt have my friend help me for that little bit, i would have been screwed. Trust me, doing it this way is much much easier then trying to attach the manifolds to the head AFTER the head is back on the block. Its not a "mistake" if you dont do it that way, its just what we have found to be an easier way to do the whole process.

You definetly want to remove those rockers to remove the pushrods. ..why did you not want to mess with them? Its not like they have to be set a certain way or anything, just unbolt them .. set them aside (hopefully in a order that helps you remember which set went where) and then when you have the head back on and the pushrods in place, put the rockers back on to the specified torque. Its a very simple step in this whole procedure comparitivly.

Is it my imagination, or do I not need to remove the power steering pump and hardware to get the head off?

I got a goood start on it, valve cover off, and lots of other hardware removed and disconnected, and I found huge 1/4" thick pieces of hard carbon laying on the top of the head. Scary site indead. I will try and post pictures tonight, one look is better than a good horror flick.

So, like I said, doesn't the power sterring pump and hardware need to come off, along with the two A/C compressor bolts?

I am starting to lean towards pulling all the rest of that mess at once as I am having troubling figuring out how to get to the bottom bolts. Looks like a tight fit going in and out

Also did you guys pull the hood, for easier manuvering or leave it on?

Ecomike said:

Is it my imagination, or do I not need to remove the power steering pump and hardware to get the head off?

I got a goood start on it, valve cover off, and lots of other hardware removed and disconnected, and I found huge 1/4" thick pieces of hard carbon laying on the top of the head. Scary site indead. I will try and post pictures tonight, one look is better than a good horror flick.

So, like I said, doesn't the power sterring pump and hardware need to come off, along with the two A/C compressor bolts?

I am starting to lean towards pulling all the rest of that mess at once as I am having troubling figuring out how to get to the bottom bolts. Looks like a tight fit going in and out

Also did you guys pull the hood, for easier manuvering or leave it on?

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Yes. Remove the ancillary hardware so you can pull the head and manifolds as a unit, or so you can manoeuvre everything out of the way. If you just remove the two screws from the aircon compressor bracket to the cylinder head, be sure to loosen the bottom screw (at least!) so you have some wiggle room to get the thing the rest of the way out of the way, and give you some position allowance when you're putting it back on.

I did not pull the hood - but, as I said, I was doing the job lone-handed, and putting a hood back on yourself is a pain. If you're using a hoist, you may find it useful to remove the hood - else, you can work around the thing while it's in place.

5-90 said:

Yes. Remove the ancillary hardware so you can pull the head and manifolds as a unit, or so you can manoeuvre everything out of the way. If you just remove the two screws from the aircon compressor bracket to the cylinder head, be sure to loosen the bottom screw (at least!) so you have some wiggle room to get the thing the rest of the way out of the way, and give you some position allowance when you're putting it back on.

I did not pull the hood - but, as I said, I was doing the job lone-handed, and putting a hood back on yourself is a pain. If you're using a hoist, you may find it useful to remove the hood - else, you can work around the thing while it's in place.

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Thanks, that is what I was afraid of.

There is something purely SADISTIC and demonic about needing to remove 10,000 things just to get to a part or parts you need to work on. :laugh3:

I remeber stories about pulling the engine to change the #8 plug or pulling the bumper and radiator off to change the water pump belt on old Chevy Corvettes, so I guees it could always be worse, LOL. Still I hate all the extra work.

It would be interesting to see a vehicle designed just by lazy mechanics someday who knew they would be the ones fixing anything that broke.

Ecomike said:

Thanks, that is what I was afraid of.

There is something purely SADISTIC and demonic about needing to remove 10,000 things just to get to a part or parts you need to work on. :laugh3:

I remeber stories about pulling the engine to change the #8 plug or pulling the bumper and radiator off to change the water pump belt on old Chevy Corvettes, so I guees it could always be worse, LOL. Still I hate all the extra work.

It would be interesting to see a vehicle designed just by lazy mechanics someday who knew they would be the ones fixing anything that broke.

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I've said it before and I'll say it again - an engineer is, by nature and education, lazy. If vehicles were purely designed from an engineering standpoint, a full tune-up, filters, and oil change would take about fifteen minutes, and require no hand tools (or maybe a pair of pliers.)

Then you get designers, accountants, and lawyers involved - most of whom know little to nothing about engineering, and even less about mechanics. Computer-aided design has made things even worse - when you were drawing lines manually with pencil and pen, you still thought about where they went, and you could spot most problems. When it's done with a click of the mouse (and the computer just checks your maths, and not your design,) you don't think anymore.

I used to work for a guy who had a 30th anniversary Camaro RS - the #3 and #7 plugs could just be changed with the engine in place, but you could forget about the #4 and #8 plugs.

On the Saturn coupe, you have to unbolt the engine and lift it about a foot to R&R the alternator.

Manufacturing doesn't help, either. Ever see how a Benz is built lately? They put the frame on a conveyor, and robots build it back to front. I had to change the rear main on a 450SEL once upon a time (mid-1990's or so, car was about 1985 vintage,) and I had to shoot the top two bellhousing screws from overtop of the axle, using about seven feet of extensions. I checked carefully - that was the only way to get to the thing! Easy enough for a robot that was purpose-built (the engine and transmission are dropped in as an assembly anyhow,) but a pain for the mechanic. I found out that charging the guy $3,000 to do the job was massively underbilling (of course, I found out after the job was done, not before I bid on it. Dealer wanted about $10K.)

Everything is built for "ease of manufacture," not "ease of service." Problem is, any mechanism with one or more moving parts requires service sooner or later...

Ecomike said:

Is it my imagination, or do I not need to remove the power steering pump and hardware to get the head off?

I got a goood start on it, valve cover off, and lots of other hardware removed and disconnected, and I found huge 1/4" thick pieces of hard carbon laying on the top of the head. Scary site indead. I will try and post pictures tonight, one look is better than a good horror flick.

So, like I said, doesn't the power sterring pump and hardware need to come off, along with the two A/C compressor bolts?

I am starting to lean towards pulling all the rest of that mess at once as I am having troubling figuring out how to get to the bottom bolts. Looks like a tight fit going in and out

Also did you guys pull the hood, for easier manuvering or leave it on?

Click to expand...

As i stated in my post on the previous page, i removed the top two A/C bracket bolts that go into the head. I didnt need to loosen or remove the bottom, and the head came out and back in without any issues from that bracket area.

I unbolted the PS pump from the intake, and just rotated it out of the way. I didnt remove the fluid or anything.. and i had no problem with spillage.

By any means comparitively speaking ... i dont think this job was all that hard. The XJ is just so easy to work on.