3.9 V8 BUYING

[SHREEVE]

G'day ladies and gents

I've been looking a disco's for some time know and was wondering if any can tell me if the series one 3.9 disco v8 engine has the same issue as the d2 4.0 v8 with slipped liners and cracking blocks???

Cheers,
James

[85 county]

yes

[Homestar]

Apparently so - if they have ever seriously been overheated then you will have issues. BUT - that's not to say they are bad engines if in good nick and have been looked after - there are plenty of them out there doing their thing very well.

[Gary S11]

I read and I'm sure I will be corrected if wrong , that the only differace between the 3.9 and the 4 ltr is the inlet manifold design and that all others specs are the same ??????. Gary

[PhilipA]

The 4litre has a completely different bottom end with larger main bearings, although still only 2 bolt.

I believe there was a faulty batch of 4litres where the sleeves could be removed by hand with the block warmed. There is a video about this on utube.

The Thor 4 litre also has the revised manifold but runs hotter than a 3.9 partly because of the thermostat arrangement.

My 3.9 in a 92 RRC has now done 211KK with no sleeve problems, but this is only possible if never overheated and always run with a clean radiator. Mine always runs at 88-93C but heats to 98 when turned off from heat soak.

If you have a blocked radiator and it gets much over 100C then it is highly likely that the sleeves will become loose at some stage.

So it is very hard to tell when you buy one what its history is. The temp gauge should NEVER have exceeded half on the scale.
Regards Philip A

[101RRS]

The 4litre has a completely different bottom end with larger main bearings, although still only 2 bolt.

Regards Philip A

The 4 litre has 4 bolt mains - two vertical bolts and two cross bolts.

[85 county]

they also have a sort of a lip under the liner, not that this helps much

[PhilipA]

Just on the temperature thing.
I went into Byfield National Park near Yeppoon today.
There is a very long and steep sand dune on the way in, and I failed first attempt as I took it too slow. After reversing down the hill , my temp was 100C so I didn't turn off but ran it at about 1500RPM for several minutes to cool down.
I have a digital temp gauge , and I was surprised at how quickly it rose. if I would have turned off it would have risen to 105-110C , with possible sleeve implications.
Just posting to show how easily it can happen. BTW, the temp gauge was still under half way, and had not moved!
Regards Philip A