Montero Engine Rebuild

[DanielDD]

Haven't been here in a long time. I pulled the engine back in January of this year and have been slowly putting it back together. The engine suffered a blown head gasket at 250K miles, which necessitated the rebuild. I took the block to the machine shop and had them do a .020 overbore and had both heads rebuilt. New .020 pistons installed, new bearings, the whole works.

The last couple of weeks I pretty much finished everything up and placed the engine back in the vehicle. The only things left are hooking everything back up. I sent out my injectors to be refurbished, so I'm awaiting them, plus I need to clean up the plenum and then I'll be ready to perform the initial start.

The latest task involved cleaning out the oil cooler as the whole engine had the familiar milkshake consistency due to mixing of the oil and the coolant. I used a pump to force mineral spirits and denatured alcohol thru the cooler. I had to order new o-rings for the oil cooler lines, which will be here mid week and then I can fill the oil cooler with oil and hook it up to the engine.

The weather is starting to turn cold here and I need to get this vehicle out of my shop. I bought a Mercedes SL500 last month and I need to get in in my shop so I can get it on the lift.

My wife has taken to calling my Montero as "Dan's Folly". I originally bought this vehicle as an off road rig, but truth be told - it was a passing fancy. It remains to be seen what the future holds for the Montero.


I will add more pictures later on this week...

 

[Salonika]

You're in too deep to stop now!

 

[offthepath]

Looks really good! If you get tired of it let me know!

 

[The Viper]

That looks awesome! How much additional horsepower will the overbore give you?

 

[DanielDD]

Looks really good! If you get tired of it let me know!

I'm already tired!

 

[DanielDD]

That looks awesome! How much additional horsepower will the overbore give you?

100 extra horsepower! :Wow1:

Actually, I have no clue. I guess I could do the math, but its not worth it. Biggest increase is going to be a newly built motor with better sealing and compression, with a slight bump in HP/TQ due to the overbore.

 

[normal_dave]

Let's not get too hasty, while the SL500 Merc is a fine work of German engineering and art, it won't take too kindly to fording the local stream, and I doubt it will work as well as the Monty pulling the "young'uns" around the yard on a trash can lid in the snow...:sombrero: (It will work lots better than "The Mazdie" with mud grips...(well, ok actually all terrains)
Just ask Live Action Nick:

https://www.facebook.com/LiveActionNick/videos/284812308679094/

Get that Montero back on the road, your wife will thank you when the next "Blizzard of '93" passes through in the next 100 years or so...

 

[evomaki]

This looks really nice. Wish mine looked that spiffy but you have gone through a lot of work. I have some questions if I may. What gasket set did you use? Rod and main bearings?Pistons? Oil pump? Anything interesting to note from assembly? How were your valves and springs after that many miles, still good?

 

[DanielDD]

This looks really nice. Wish mine looked that spiffy but you have gone through a lot of work. I have some questions if I may. What gasket set did you use? Rod and main bearings?Pistons? Oil pump? Anything interesting to note from assembly? How were your valves and springs after that many miles, still good?

I had the machine shop order all of the engine parts (gaskets, bearings, pistons, oil pump etc) when I took the block and heads in for machining. I don't directly have the name in my head at the moment, but I will look this evening and get it for you. The machine shop owner (which I have trusted for a number of years now) routinely buys parts from these guys all the time, so I didn't have any cause to question the quality of the parts. However, I will tell you this, a good majority of the parts were made in China. When I questioned him about this, he indicated that most everything now is sourced from China. If you want OEM Japanese quality, you will most likely pay dearly for it. All of the parts that went into my build seemed (to me) to be of good quality, including the gaskets.

I had a couple of issues with the parts; The piston rings required me to re-size them so I had to purchase a ring grinder. 1st time I've ever had to do this and I have built a number of engines in my lifetime. It was a hassle to do this as you can imagine. I had to grind both the top and 2nd rings for all cylinders as they were too tight for the specification. So, this took a lot of time... grinding, cleaning the ring - inserting it into the cylinder and measuring it - several iterations of doing the until they're within spec.

Initially we thought they sent us the wrong ring set, even though it was correctly marked, so they sent me a complete 2nd set of rings and they were the same - so I had no choice but to re-size them. 2nd issue was with the oil pump. Their catalog specified the wrong oil pump and we didn't realize it until it arrived and I noticed the difference in the pumps. The supplier quickly sent me out the correct pump without charge.

Valves and springs were fine after 250K miles as they were all within spec. Heads were dis-assembled & cleaned, new valve seals installed, including a complete valve job and the heads were re-surfaced. If you're going to do it once - do it right the first time.

Other assembly issues of note: Timing the cams with the timing belt was...irritating. The procedure required me to purchase a specialized tool for cocking the idler bearing just right while you use an inch-pound torque gauge to determine the correct torque before locking down the nut. I must have had to do this numerous times before I got it right. Everytime I tightened the nut, the resulting torque value would increase and the final caliper distance reading would be incorrect.

I can't imagine anyone doing this in vehicle without a lot of patience (which is a quality I don't readily possess)..

 

[DanielDD]

Let's not get too hasty, while the SL500 Merc is a fine work of German engineering and art, it won't take too kindly to fording the local stream, and I doubt it will work as well as the Monty pulling the "young'uns" around the yard on a trash can lid in the snow...:sombrero: (It will work lots better than "The Mazdie" with mud grips...(well, ok actually all terrains)
Just ask Live Action Nick:

https://www.facebook.com/LiveActionNick/videos/284812308679094/

Get that Montero back on the road, your wife will thank you when the next "Blizzard of '93" passes through in the next 100 years or so...

This is my 1st Merc. I've pretty much been a BMW guy, so I decided to get my feet wet with a Merc this time. I do like the V8 power though....

 

[JAVYPRO]

That is looking nice. I had my 2.6L done by a recommended machine shop I Snellville GA and they did a great job. I did all the assembly, well still some more to do as it is going turbo but the last tool I need is a cherry picker to remove and install the engine.

Javy

 

[evomaki]

Indeed nice as Javypro said. I too am amazed at the number of parts made in China. I guess we have not much choice but to get over it. The key as you all have mentioned is a good machine shop and do as they say. Is there any special procedure with these engines about priming the oil pump. I don't mean assembly lube on parts and cylinders with a wet wall from a dunked piston. I have not built many engines (and old BMW 4 bangers at that) and there was no need on those, but I have heard stories some engines need a special procedure. A guy I once knew said he messed up an engine in a Ford Ranger years ago by not priming the oil pump.

 

[DanielDD]

I'm not concerned about priming the pump on this engine. It is difficult to do as the pump is driven by the crankshaft. You can however, prime the engine by removing the oil pressure sensor and using an external pump to force oil thru the engine if you want to insure a full prime, but I don't think it is necessary. I don't plan on doing anything special other than turning the key and starting it. The system should build pressure in short order without causing any damage.

 

['round n' back again]

prime these pumps by filling the gear cavity with vaseline, . creates terrific suction and ur off!
at least on the 3.0 engine

 

[DanielDD]

Engine is complete, back in the vehicle and RUNNING!!!

There were a few bumps along the way. I had incorrectly torqued the intake manifold, which created a massive coolant leak prior to startup. Much of the coolant pooled in the V of the block, so I had to remove the plenum and the intake. Turns out that I didn't specifically follow the torque recommendations in the manual. It states to start the torque on the passenger side first and I started on the driver's side because I figured it didn't make any difference. Well, I was wrong, obviously. Initially I was concerned that the cylinder heads may have been the issue because I had their surfaces milled flat which took off .0010-.0015 off them. If you take too much off the intake won't seal correctly onto the cylinder head mating surface. So, I'm glad that wasn't the problem.

Neck surgery kept me from getting all this done in a timely manner, but last weekend I was able to do an initial crank of the engine and found it wasn't priming the fuel pump. I had the fuel injection fuse in the wrong location (oops). Once I rectified that it started right up. I let it run for about 15-20 minutes with the heat on and shut it back down. I can't drive it yet because I've yet to put on the hood and get the car registered and get plates on it - but for now, after a year of having it torn down, its alive and well.