1.8l head gasket removal and install

[Coder24]

I need a link to a guide to installing and removing a 1.8l head and replacing the head gasket. i searched and only found 2.0 models. Thanks

 

[JayRolla]

2.0 head is the same.

 

[Coder24]

isnt the 2.0 head DOHC? I believe it is. The 1.8l is SOHC.

 

[danny7481]

get a haynes or chiltons manual.
the 1.8L head is easier than a 2.0 since it SOHC, instead of DOHC.

and ofcoarse the 1.8 has a distributor instead of coil pack.

 

[JayRolla]

isnt the 2.0 head DOHC? I believe it is. The 1.8l is SOHC.

Ohh sorry, I though you had the 1.8l DOHC. Ive used these heads on turbo dsms. And its not easier, its just a lighter head.

 

[danny7481]

Ohh sorry, I though you had the 1.8l DOHC. Ive used these heads on turbo dsms. And its not easier, its just a lighter head.

to me, its easier because if your just replacing the head gasket, you dont have to remove the camshaft, like you do on the 2.0. and ofcorse on a 1G dsm with a 1.8 you have more room under the hood to get to stuff.

 

[JayRolla]

to me, its easier because if your just replacing the head gasket, you dont have to remove the camshaft, like you do on the 2.0. and ofcorse on a 1G dsm with a 1.8 you have more room under the hood to get to stuff.

Why would you remove the cams when doing a head gasket.

 

[danny7481]

no, im saying you dont have to remove the camshaft on the 1.8 to do a headgasket.
but you do on the 2.0, casue you cant get to the headbolts with the camshafts in.

 

[Bohrn]

I don't know where to find one but I can give you some pointers for sure.

drain coolant.disconnect downpipe from exhaust manifold. disconnect wiring from injectors and other things. disconnect fuel lines. Remove and disconnect any other things that will physically hold the head back. Remove only what needs to be removed tho. Extra stuff is just extra time, plus you raise the risk of damaging something while removing it. Leave the manifolds on. Saves lots of time and you don't have to replace those gaskets(if they are good)

Remove the upper timing belt cover. put the engine to top dead center. You will have to look up the marks for this. There will be a mark for the cam gear and put the crank pulley timing mark on the "T" mark.

work the timing belt off the cam pulley. It will be fairly tight but can be done and saves you lots of time.

remove the valve cover. break loose the head bolts in the same order that you would tighten them. Starting in the middle, criss-crossing, sortof like a set of lug nuts. If you can find a pattern on-line follow that. Any 4 cylinder OHC engine should be similar. when the bolts are all off, break the head loose. It may require some prying or a sharp smack with a hammer. Don't pry on the mating surface of the head, but put the bar on something that is just a lump of metal. Sometimes applying the prying force at the same time as a sharp smack will do it.

place the head on a work bench. Using a good flat sharp scraper, carefully scrap the old gasket off both the head and the block. Be careful not to gouge the head as its soft aluminum. Get all the old gasket material. both surfaces have to be smooth and clean. If the head is warped, you need to have it milled anyway. when its all cleaned up, you will have to blow out any coolant or oil in the bolt holes in the block or the torquing process can break the block due to hydraulic pressure. It may not, but it definately can, so be safe. Make sure the dowels are in the block, not the head.

set the head gasket correct side up and facing the right way on the block, with the dowels in the block. have an assistant help you lower the head and manifolds back onto the block, and be careful here. If you are using new head bolts, put them back into the holes. If you are reusing them, clean up any rust or crap from the threads and lightly oil them. Finger tighten them. Then torque to spec. Do it in 2 steps, eg, if the final torque is 55 ft/lbs, go 25 in sequence and then repeat to final torque. You will have to find the torque specs for that, very important. do that exactly as written, and pay attention to the angle as well. Eg 45ft/lbs +90 deg.

With the help of an assistant, refit the timing belt. Make sure its all still in time, and don't move any pulleys. This will be fairly hard, but you can do it.

Install a new valve cover gasket unless the old one is very new. Use a little silicone at any sharp corners, not too much and only at the corners. clean the surfaces first.

once thats done, its all just bolting up the other stuff.

**disclaimer** this is just from memory from the Mitsu single cam engines I have done at work on customers cars. Also it will vary from factory manual because I have told you to leave the manifolds on and not pull the whole timing belt setup. This will save you alot of time, but make sure you take your time and do it carefully. I may have forgotten something, and I may be telling you to do it in a way that is not what most people will suggest, but it works well and will save you lots of time with no ill effects providing everything goes well.

 

[Coder24]

no, im saying you dont have to remove the camshaft on the 1.8 to do a headgasket.
but you do on the 2.0, casue you cant get to the headbolts with the camshafts in.

Uhh....No. My old mechanic and I did my headgasket on the turbo car and i didnt have to remove the cams at all. Not even the gears. I just dont know how to do a 1.8 or do the timing at all.

 

[JayRolla]

Yea never had to remove cams.

Also when putting the head bolts in be sure to blow all material out of the stud holes in the block. Oil will get in there and it will cause a false reading on your tq wrench. 10 miles down the road boom blown head gasket.

 

[danny7481]

i dont know about a turbo but on the 420a, i couldnt get to the head bolts without removeing the cams unless i wanted to go at an angle and risk stripping the bolt head, which i didnt want to do that.

 

[Bohrn]

just to clear things up here, the 1.8 single cam Mitsu engine in question is alot different than the 1.6, 1.8, 2.0 or 2.4 twin cam engines and completely different from the 420a Chrysler engine.

 

[JayRolla]

Yea that was cleared up on the third post, I didnt know he had a SOHC head.