Thread: 3.9 complete rebuild any tips, tricks, things to look out for?

Getting there very slowly with the rebuild. Last thing I am waiting on is new injectors coming from the US.

So far, costs for this have gone well above $4K. Aggravation and frustration WAY more than I'd accounted for.

I'd not anticipated having such a hard time with machinists. Finally found some guys who did the right thing by me, so the business part of the build could commence. I'm very much looking forward to turning the key on this in the next 10 days or so, but since the car has been off the road since January I wouldn't be surprised if there's another hitch that puts it back a week.

Where I sit now, I wish I'd never undertaken the job, primarily because of the high cost and countless hours I've put in. I should have kept the money in the bank, broken up the Disco, sold off the good bits and bought a diesel. That, or just buy a banger and swap engines. I hope to be smiling a bit more in a week or two.

I've taken a heap of pictures but will post them once it's all finished.

Originally Posted by MacMan

Consider how badly you want to do it. I found myself with the Disco parked in the drive earlier this year, crippled with a chopped out spark plug hole and the plug still stuck.

It was only last week that I collected the block, heads and crank from the machinist having had flanged liners put in and bored to match new 9.35:1 pistons, new cam bearings fitted, heads reconditioned (inc 5 new valves) and the crank machined 0.010". All that and the new bits to go have cost painfully close to $4K. Yes it will be absolutely peachy once I have a new, freshly rebuilt engine that's better than new with the higher comp pistons, but it had bloody well want to be. $4K constitutes a decent chunk of the diesel 110 I'd like to own in a few years.

This morning I'm collating torque figures things to double check in a checklist since I'm having to do the work in the evenings. Nothing hard, but as pointed out it's fernicketty fiddly work.

You will have a lot more fun with your 3.9 than a 110 oil burner! Build the 3.9 and gas it. They love gas. Have built mine with gas in mind but will run it in with unleaded and then set the gas up.

Couple of picks of my new 3.9, not far away from going back into my Stage One. Looking forward to running it in.

Regards Warrick.



IMG_4578-web by wpalmo, on Flickr


IMG_4581-web by wpalmo, on Flickr

Should get to turn the key today. I'd hoped to get it all finished yesterday but ran out of time and energy. Starting to look like it used to though.

It goes!

I have an injector problem - either an injector its connector - so it runs very rough on ULP with the new Bosch injectors. I'll debug it tomorrow. On LPG, it seems to want something in the order of 15° advance. Cam run in went fairly smoothly. I had an airlock in the cooling system which meant the converter froze up, but it was pretty simple to bleed it out once after tipping a hot kettle of boiling water on the converter.

Final mop up tomorrow and I'll post some pics. This is a HUGE relief after all the trouble I've been through with "experts" and "professionals".

That's great to hear. It really sounds like you had my kind of luck and wound up dealing with some true idiots.

Haha... yes. Well I certainly know whom I would not recommend to do a liner job. I'll reserve judgement on the balancing mob until I've run it more. I'm heading out this morning to look for leaks under the car and check out the fuel injectors. Assuming it's all OK I'll swap to normal glycol coolant and rebleed the cooling system before going for a run a 100km run.

Injection gremlins fixed!

In my haste to get things done I'd mixed up the #1 injector harness with a sensor plug. Swapped and she runs superbly on the Bosch injectors. Certainly smoother idle and better response than with the stuffed old Lucas units. The 15° or so degrees that provide happiest LPG running cause it to ping terribly on ULP, but I'll find the happy setting for ULP and just retain two witness marks for both fuels. Now to see what the ULP economy is like.

Just been for a decent run. Starting to smile again now. All running well. Power on ULP is good and the running very smooth. But with the ignition advanced to suit, LPG is very pleasing. I look forward to it loosening up over the next few thousand KM.