Replacing Gen 3 Heads (Like a Virgin). Any Recommendation?

[DJPurdue]

Ok, since you've determined to get the heads serviced, that's good, but I'd still like to verify why you didn't have compression. I would pull the rocker arms, and inspect the valves as previously described to determine if #1 and #4 are the cause of the compression loss. You'll want to temporarily re-install the spark plugs of course. I know I seem hung up on this, but you said you wanted to get it running, and that means absolutely verifying the cause of the issue. Why was there no compression on those two cylinders?

I think it would also be a great time to clean/bleed your lifters. This is a time consuming, but not costly procedure. It will allow you to be sure of proper oiling, and no noisy ticking lifters in the engine later. When you go through this procedure, you'll want to look for broken/cracked black plastic rings on the lifters, and replace the lifters that have the broken parts, or won't hold pressure as you pump them with diesel fuel.

Thanks normal_dave. As much as I like to be a DIY-er, yesterday, I dropped off the heads to the machine shop yesterday right as they were closing up. I talked to the guy there and he said he will clean and bleed the lifters, replace the valve seals and the rest of what is needed. He will have it ready for me in a day or so. However, I will definitely experiment this the next time I am at the salvage yard.

As far as cleaning pistons, re-install your crank bolt, use the wrench to rotate each piston to TDC, then use a putty knife/scraper and a wire brush mounted in a drill to clean the scale off of each piston. Don't get too aggressive of course.

Sounds good. Is there any liquid that you recommend using? Can I spray it with gasoline? Another question (maybe a little dumb) when you say TDC I am assuming it means bringing each piston to the top most position? Because the crank rotates 2.5 times or so for each cam rotation, when doing the reinstall, I should get the pistons in the same position as I have them currently, right?

As far as the timing marks, basically yes, you will just re-align everything, but use the factory service manual directions for this. Mitsubishilinks.com I also like the Rock Auto Aisin timing belt kit, It has the Mitsuboshi belt, but it appears it is a high quality timing belt, and oem idler, adjuster, and water pump.

I will order the set today.

Also consider new rear cam seal O-rings, use Mitsubishi genuine, also replace the front cam seals at this time, I used aftermarket National, hopefully the machine shop has included this in their price. You will also want Mitsubishi valve cover gaskets. I use RCHillmitsubishi online parts, and have gotten good service, and the lowest prices that I could find, at least.

Edit: Forgot to add, be sure to inspect, clean, and replace your pcv valve, and piping as this is a potential source of excess oil usage, and your exhaust ports show some extra carbon deposits, this is not unusual.

I replaced the rear cam O-ring (for the G74 there is only 1 on the left bank) about a month ago. It was leaking oil so definitely needed to change that.

Front cam seals are being replaced by the shop. He said he will get it from Mitsubishi. There is a dealership right across from the machine shop. Very convenient.

Valve cover gaskets were changed by the previous owner so does not leak any more. I checked those when I was replacing the spark plugs, wires, etc. I had to replace the spark plug seals so that is good now.

I have replaced the PCV valve while replacing the spark plugs. So I am covered on the regular maintenance.

Can't wait to be back on the road again

Really appreciate your inputs.

 

[normal_dave]

Forgot to answer your questions.

TDC= Top Dead Center, highest point of piston travel for each cylinder. This is just to protect the cylinder walls while housekeeping, and gives better access to the piston top, waste can be brushed aside, keep trash out of oil and coolant passages.

I usually dry clean, then wipe up with some odorless mineral spirits and a clean rag, low-lint. I'll only put gas in the gas tank, although I have on rare occasion used charcoal lighter fluid on damp kindling wood in the outdoor fire pit...

As far as position on re-assembly, follow the factory service manual, since you don't know what position the cams will be in after the engine shop. Set TDC on the crank marks, and align marks on the cam gears to the marks on the timing covers.

 

[DJPurdue]

Forgot to answer your questions.

TDC= Top Dead Center, highest point of piston travel for each cylinder. This is just to protect the cylinder walls while housekeeping, and gives better access to the piston top, waste can be brushed aside, keep trash out of oil and coolant passages.

I usually dry clean, then wipe up with some odorless mineral spirits and a clean rag, low-lint.

Got it. I will make sure to just dry clean while moving from piston to piston and making it TDC. Then move it all back to how I took the head off. Taking a picture would be best.

I'll only put gas in the gas tank, although I have on rare occasion used charcoal lighter fluid on damp kindling wood in the outdoor fire pit...

That's funny!

As far as position on re-assembly, follow the factory service manual, since you don't know what position the cams will be in after the engine shop. Set TDC on the crank marks, and align marks on the cam gears to the marks on the timing covers.

Noted. I asked the shop to position them back to the cam gears on the timing marks. I also gave them the valve covers just for this reason. Also printed the FSM for reassembly. Just need to wait to get everything now.

Thanks normal_dave. And "waytoomuchwritinginposts" is a good thing for people like me with little or no knowledge of engine internals.

 

[RyanY]

Because the crank rotates 2.5 times or so for each cam rotation, when doing the reinstall, I should get the pistons in the same position as I have them currently, right?

The crankshaft goes through exactly 2 revolutions per camshaft revolution.

Before you reassemble the heads, set the #1 piston to TDC and align the timing mark on the crank pulley with the mark on the timing cover. Since the shop is going to assemble the cams for you before you install the heads (typically you would install the cams after the heads are already reinstalled), check that the camshaft gear timing marks are as close as possible to the timing marks on the heads - otherwise installing them with the cams not timed could bend the valves. This needs to be double or triple checked before assembly.

 

[DJPurdue]

Thanks RyanY.

check that the camshaft gear timing marks are as close as possible to the timing marks on the heads - otherwise installing them with the cams not timed could bend the valves. This needs to be double or triple checked before assembly.

This is the problem I am facing at the moment. On the cylinder head on the driver side

, I was able to line it up after I had set the #1 piston TDC by moving the crank pulley. It perfectly lined up. However, cylinder head on passenger side

I am unable to line up to the timing mark. When I turn it by using the 17mm socket on the cam gear it jumps to 3 positions except for the timing mark on the valve cover. My understanding is that the cam gear cannot be installed in reverse because there is a pin that it has to line up to to be able to tighten down the nut.

I wanted to check here before I run back to the machine shop which is an hour and a half away (making the whole trip about 3.5 hours) which is not possible on a work day.

Let me know your thoughts. Thanks.


EDIT - SOLVED. Took the head to a shop and the guy told me to not use a ratchet but a box wrench or regular socket wrench to hold the gear from spinning too much and also can move the gear anti-clockwise. Did that and its set at timing now. Put the heads back on. Like the FSM says, torqued them once backed out and re-torqued them to spec.​

 

[normal_dave]

Not sure if you saw this discussion on another post, but it proved very informative regarding getting the timing belt right, and in your case aligning the cams.
http://www.justanswer.com/mitsubishi/8sxbg-mitsubishi-pajero-nl-just-done-timing-belt-change.html

Another good discussion from Doug C regarding timing marks...
http://www.justanswer.com/mitsubishi/4ore2-1999-montero-sport-set-timing-marks-passenger-side.html

 

[RyanY]

However, cylinder head on passenger side

I am unable to line up to the timing mark. When I turn it by using the 17mm socket on the cam gear it jumps to 3 positions except for the timing mark on the valve cover..​

You're fighting against valve spring pressure that's wanting to turn the camshaft. You'll have to devise a way to hold the camshaft in place while you get the timing belt on.​

 

[DJPurdue]

Good morning all,

Good news! I have the car up and running for about a week now. All is good. I was literally scared out of my pants when cranking it the first time but it fired right up. Have changed the oil after running it for 2 days and flushed the radiator. Seems to be great.

I did notice a bit of squeal from the accessory belt when I rev the engine. I believe that may go away or I might have to change the belt.

Thank you every one for your really useful advice. I would not have been able to do it without you.

Normaldave - your words were my biggest inspiration "stay strong, you will be back on the road soon"

 

[nwoods]

This was inspiring. Great job DJ