Thread: Discovery 1 V8 3.9 1999

A few weeks ago I discovered there is about 70% of an engine alarm already on the vehicle. If you're handy with a soldering iron its a slightly more factory option than the engine guardian

Series 1 temperature warning lamp | DiscoWeb

Originally Posted by Ronski

All looks like one of the cleanest engines I've seen, but you did say you were cleaning everything.

Cylinders 1 and 3, I take it you have cleaned the pistons, sometimes water getting in turns to steam and blasts the pistons clean. So If you've done it, it should be fine.

Have a really close look at the head gaskets and block, any sign of a slipped liner would be hard to detect, block should be flat where liners are, and any tiny ridges or indent around the metal rings of the gasket. When a liner moves up, it impacts the gasket and leaves a ring. I doubt if they have judging by the pics. worth checking.

The machine shop will re seat the valves and check heads. leaking valves would cause low compression.

I hate it myself, after pulling a motor apart looking for a possible cause and find nothing. equals sleepless night worrying.

Before 'fully' torqueing the heads down, assemble the valve train. I would measure the actual lift of the cam lobes, it's in the rave manual, can be measured at the tappets end, top of pushrods, make sure all are the same lift.

Good luck, you obviously know what your doing, I can't think of anything else that hasn't been mentioned, to cause low compression and over heating.

Keep the pics coming, I always like to follow an engine rebuild thread, planning on a rebuild of my good Disco later this year.

Cheers,
Ron.

Ok sorry for delay in update, machining heads and awaiting parts and a lot of work : ) plus kept finding " stuff " : ) : )
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Split and hard hoses , crappy wiring , some worn out looking items, rewing the crappy lead from the distributor to the coil pack made a big difference too, mainly the new coil pack but new cleanly wired cable was a very notable difference to idle and rev range. New spark plug Leads are on their way too.

So as I was staring into the dismantled engine I kept tooing and frooing over changing the Cam....so I did !! new cam, tappets and timing chain nothing special just all original items..... In for a penny in for a pound. I did manage to do this without removing AC pump and Condensor just remove the small brackets holding the aluminium pipework along the body under the radiators filler/expansion tank. Remove Rad expansion tank and Lift pump onto the bracket and hoist up the condensor. I did this just as I was ready to slide in the new cam so minimal stress. I did use Penrite Cam Lube and lots of it on the cam lobes and the Tappet faces. RAVE does suggest only engine oil but I read many conflicting articles so I went with Cam lube, on start up it made for a super smooth bedding in so I'm glad I used it but could have been just as good with engine oil so draw your own conclusions.

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Had the engine's crank at TDC and photographed the exact position of the cam and timing chain and reinstated the new ones exactly the same position. The cam I removed wasn't really that worn and the timing chain was ok too but again probably overkill but for $300+ I wanted a new one in the car so I knew where I stood from the get go.

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Also removed the injectors and cleaned with diluted injector cleaner using a syringe and clear hosing from syringe and over the entry end of the injector, hooked up positive and negative leads with small crocodile clips to a 12v battery ( small motorcycle battery will do ) I didn't connect the power to the battery terminal I just tap tap tapped it pulsing the injector cleaning fluid through the injector while squeezing the syringe. I did this several times to each injector during a 24 hour period and cleaned out the crud and also cleaned the fuel rail. Reassembly is a little awkward but had much harder troubles with old motorcycles so this was pretty easy in comparison. I got a good tip to put a little petroleum jelly on the new O Rings, worked a treat. Cleaned the inlet manifold with Oven cleaner.

Removed and cleaned the oil pan and pick up, it was full of crud, cleaned with petrol and CT18.....it came up spotless. Found some differences of opinion on sealing the pan. I did use Hylosil 100 RTV ALL round the pan and torqued bolts in sequence at to spec. So far so good. There was a gummy cork mess on it previously but it seemed to be doing the job.

Torqued everything back onto Manuals specification. I di replace the steering reservoir and pump hoses as they were very hard.

I did prime the petrol to the engine but not the oil, I figured I had lubed all crucial parts and the pump gets the oil around the engine pretty quick as is so I opted not to worry about priming her. She started first flick of the switch, little noise for about 15 seconds then got quieter and quieter, ran the engine around the 2/2500 rpm, I did not Idle the engine during bedding in of the cam and tappets.

So on refection having replaced, Rad, camshaft, tappets, timing chain, water pump, thermostat, all coolant hoses, ignition module , 3 temp sensors , coil pack and lead, plugs , head gaskets, all fluids etc I think it was the sum of all the small parts that made the difference. Split hoses and crappy radiator, poor connections all contributed so I can't say for definite what the main culprit was. But having replaced parts , machined heads cleaned up connections all for the total of $2,500 DIY I now know what's definitely been done with the car.

Engine is running sweetly on 8 degrees BTDC ( APPROX ) NO marks on my rusty balancer ( might need to do something about that in the future : )

Oh soaking exhaust manifold bolts AND spacers was a mistake, burning oil on the manifold filling the carport for 15 mins : ) : )

Anyway all done even got a new stripe coming for her bodywork and cleaned she is now happy : ) ......... I hope !! will keep updating if I have any issues to report.

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RPM in Kunda Park did an awesome job on the heads, machined both surfaces very minimal and skimmed the ports, reseated the valves , fitted the new valve seals and give the heads a good bath all for $370.....awesome job at a very reasonable cost. I was lucky the heads were very close on tolerance but the suggestion was to very lightly machine them so you get good adhesion to the gasket....sound advice I thought.

Roverlords Mario sent me parts super fast and gave me invaluable advice on what to look out for, saved me a few times. Thank you Mario.

Atlantic British have some great youtube videos which I found invaluable, then the rest was via the RAVE manual and this great forum.