4M40 Timing chain nightmare

Mitsubishi Delica L400 production commenced in 1994 -- After much anticipation, the L400 arrived on Canadian Soil in 2009!
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Woik
Posts: 1
Joined: Fri Jun 21, 2019 6:03 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: Mitsubishi L400 Space Gear
Location: Victoria BC

4M40 Timing chain nightmare

Post by Woik » Thu Nov 21, 2019 4:47 am

Hi folks,

First off thanks to everyone for the wisdom and help here, it's a great resource. I recently learned a lot about the timing of this engine, haven't come across this info so thought I'd share what I can. This is my first post so here we go:

I bought a '95 L400 4M40 this summer and wouldn't you know it I had to replace the cylinder head. Not a huge surprise. Took it to Rocky Mountain Imports in Saanich and they replaced the head, here's where it gets interesting.

With the new head on they fired her up and there was a weird noise which John at RMI correctly diagnosed as a timing issue. They found that the timing chain had stretched (he sent me a video showing it compared to a new one... must have stretched apx. 1/2" in length). Also, they found the chain guide had worn, only not where the chain runs like you'd expect, but where the tensioner contacts the back side of the guide, (this side you can't see in situ). Both sides of the chain guide have a black nylon insert, the chain side appeared to be in good shape but the back side where the tensioner plunger acts on the guide was worn down quite a bit. The combination of the chain stretch and the wear on the chain guide was enough that the plunger was at its maximum travel and therefore couldn't keep the correct tension. This was enough for the timing to be off to the point where the valves kissed the pistons. One valve was bent and this was found when they checked the compression. So they re and re'd the head again, this time replacing all the timing components along the way. While they were in there John and Jeff checked the bottom end bearings and the piston crowns, these were in good shape luckily and so did not need replacing.

So all in all they did the job twice and needed a second brand new cylinder head to complete the job. John reassured me throughout the job I wouldn't get an astronomical bill at the end and he kept his word. I paid exactly what he quoted, plus a couple extra bucks for the timing components. I fully recommend Rocky Mountain Imports for Delica work, they were awesome to deal with and John will earn your respect.

He also mentioned that during the reassembly the timing marks can lead you astray. The timing sprockets have a vulcanized rubber insert that will breakdown over time, allowing the sprocket to slip relative to the marks. Therefore you cannot rely on the marks to guarantee the timing will be correct. Maybe some of the folks with more experience can add to this as I can't recall exactly how you ensure the timing is correct. I've had the van on the road for a couple weeks now and no issues. EGT's are wayyy lower... but mpg's not as now I'm driving a lot faster, (but still not fast lol).

poochike
Posts: 151
Joined: Sat Jun 25, 2011 12:52 pm
Member's Photo Album: http://www.delica.ca/Photos/
Vehicle: 1999 L400 Chamonix Gen2
Location: vancouver
Location: Vancouver

4M40 Timing chain nightmare

Post by poochike » Thu Nov 21, 2019 1:56 pm

Thank you for sharing your experience. I also need to give a thumbs up to John. Last year over the Xmas holidays I was starting a 3 week tour of the island when on e of my calipers seized up (for the thousandth time). I called John and they got me in the day which I believe was the 23rd or 24th Dec! They inspected the breaks all around and we determined everything should be done. Price was more than fair especially during the holidays. They also inspected the suspension, steering components and reported on their findings.

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