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Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Tue Oct 06, 2015 2:18 pm
by 4ePajero
Thanks for posting!
Looking at your meticulous work, I have little doubt that the rebuilt 3,2 will be as good as new, if not better!
You are proving that a Di-D can be successfully be re-built.
I hope you will share the eventual costs with us.
(your labour does not count! :D )

I feel like buying an old engine and rebuild it, just for the joy of working with a well-engineered piece of history.

(I don't know whether you have worked on other brands, but my experience is that a Mitsu is just in another league as far as excellent design goes).

Again, well done!!!

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Tue Oct 06, 2015 3:58 pm
by Nick Gibson
Some more pics of injector pump fitment.
See the red circle where the scissor gear bolt was removed from. The yellow arrow shows the port where the power steering pump is bolted into. This is also where you can double check the pump timing marks.
Front view of injector pump fitment
Front view of injector pump fitment
Side view of injector pump fitted
Side view of injector pump fitted
What the engine looked like at that stage of assembly, you can see how I fixed the timing chain up onto the guides with cable ties.
Engine assembly stage
Engine assembly stage

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Tue Oct 06, 2015 4:12 pm
by Nick Gibson
Its important to note that the pump timing can be adjusted (retard or advance) as 4epikanini did with his 4m41.
Exploded view of pump
Exploded view of pump
The flange plate (#11) is bolted onto the timing case and there is no adjustment possible there, it can only fit exactly in one position. The adjustment happens between the flange plate (#11) and pump (#20) by loosening the 3 bolts (#10) and pivoting the pump around its shaft to advance or retard.
Pump advance
Pump advance
See the two similar punched lines about 3mm apart (the pump one lines up with a thicker line cast into the flange plate), they used to line up but I advanced my pump about 3mm as I was sitting with an EGT reading higher than I liked. I can always return the pump to the original setting by lining up the punch marks again if the timing is out too much. The open port next to the timing marks is where the one hall type engine speed sensor plugs in, it took them out to protect them from damage during removal & fitment of the pump.

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Wed Oct 07, 2015 1:40 pm
by Nick Gibson
After I did the timing gears & Injector pump I fitted the oil pickup & Sump.

Oil Pickup fitted with new 'O' ring
Oil pump pickup fitted
Oil pump pickup fitted
Sump cleaned up of all old gasket makes and new bead applied. I ran out of the Victor Reinz liquid gasket, I had to use the Permatex Ultra Grey, as my local parts store didnt stock the Victor Reinz product.
Sump with sealant applied
Sump with sealant applied
You have to add some extra liquid gasket over the timing plate & cover to make sure these isn't a leak in that area where all the part join.
20151004_142509 (Medium).jpg
Sump Liquid Gasket Procedure is
1. Apply sealant to sump & locally on block over timing plate
2. Fit sump to block
3. Finger tight bolts till sealant squeezes out the sides slightly
4. Wait 1 hour
5. Tighten up bolts to required torque.

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Wed Oct 07, 2015 2:00 pm
by Nick Gibson
Bottom view of rear crank output with the two bolts used to lock the crank to torque the main pulley bolt to 323Nm.
Rear crank
Rear crank
Fitted new GMB water pump
New water pump
New water pump
Oil cooler fitted
Oil cooler fitted
Oil cooler fitted
Water pump, vacuum pump & power steering pump fitted
New water pump fitted & (vacuum pump & Power steering pump fitted too)
New water pump fitted & (vacuum pump & Power steering pump fitted too)

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Wed Oct 07, 2015 3:14 pm
by 4ePajero
That Di-D is still a thing of beauty!

I should have asked earlier, but did you replace the front seal on the injection pump?
They tend to start leaking when old, which causes diesel in the sump, which obviously is not good.
Shaft seal 2.JPG

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Wed Oct 07, 2015 3:21 pm
by Nick Gibson
Piston Heights/protrusions:

In order to select the correct head gasket thickness 1-4 Notch (to achieve correct compression ratio) you need to do the piston heights. I made a slight error in that I should have done this when I fitted the piston without the timing chain in place - so I had to make a plan to turn the engine with out losing the timing of the chain.
timing Chain fixed with cable ties to guides
timing Chain fixed with cable ties to guides
So I made a plan with a spare shackle and one of the cam sprockets.
Temporary chain tensioner...
Temporary chain tensioner...
To do the piston heights you need to set the piston at TDC with the dial gauge. Then you measure the difference the top top of the block height and top of piston.

Zeroing dial gauge on top of block:
Setting dial gauge on 0 on top of block
Setting dial gauge on 0 on top of block
Measuring piston:
Check piston height (-0.035mm)
Check piston height (-0.035mm)
You measure both side of the piston along the centre line of the gudgeon pins and average the readings off all the pistons. I got 0.03375mm average which is fine for a 2 Notch (-0.05 to 0.03mm clearance range) head gasket.

Piston Heights Note sheet:
Piston heights
Piston heights
Head Gasket thickness selection specs:
Head gasket selection
Head gasket selection
All for now, I am fitting the head tonight, will post more pics when I get a chance again.

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Wed Oct 07, 2015 3:27 pm
by Nick Gibson
4ePajero wrote:That Di-D is still a thing of beauty!

I should have asked earlier, but did you replace the front seal on the injection pump?
They tend to start leaking when old, which causes diesel in the sump, which obviously is not good.
Shaft seal 2.JPG
HI Gerhard (4e)

Thanks, I must say the 4m41 is quite a solidly designed engine, very robust, everything seems to be a bit larger than necessary!

Re Injector Pump Seal: I had the VRZ pump completely overhauled earlier in the year at Randburg Diesel when my GE actuator burnt out. They did a complete calibration & service of all the seals and gaskets when they had it open for repair, so hopefully it should still be fine 4 months down the line.

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Wed Oct 07, 2015 3:53 pm
by 4ePajero
I love the "Temporary chain tensioner..." :lol:

Re: Pedro the Pajeros’ 4M41 engine rebuild.

Posted: Fri Oct 09, 2015 9:58 am
by Nick Gibson
Ok Feedback time.

Head - I had to fit all the bits to my new head from the old one, the new had came with new valves, springs etc, so I just had to swap studs, coolant outlet, and temp sender.
New Head
New Head
Fitting intake studs & coolant outlet - copper-slip to all studs as well
Fitting intake studs & coolant outlet - copper-slip to all studs as well
Installing studs with Brit-tool stud gripper
Installing studs with Brit-tool stud gripper
Intake side done
Intake side done
Mock-up of head installation - gasket down
Mock-up of head installation - gasket down
Mock-up - head on block
Mock-up - head on block
Then I fond a problem... :shock: