Couple of Rover v8 questions

[TerryG]

Does anybody know if it is possible to fit the crank from the 4.6 to a 3.5 or 4.2 (I have a couple of good engines and a 4.6 with a slipped liner)?
Also, I have been given a 4.2 short engine by a friend that has taken it out of their off road toy. It has no heads on it (or sump, oil pump, etc) it does turn over but how much resistance should I expect to start it turning as it is quite hard to start it but once it is moving it moves smoothly. I'm just deciding if it is worth keeping in "stock" or if I should sell it to a rebuilders.

[TerryG]

This is how I know it is definitely a 4.2

4275.jpg (162.5 KiB) Viewed 1374 times

I am pulling it apart to bung in a new cam and lifters, stick on some spare heads and my old front panel / oil pump to build up a working spare. Only problem is one of the surfaces on my spare (new) 4.2 cam looks like this:

rusty cam.jpg (60.32 KiB) Viewed 1374 times

I think that needs to go in to the scrap metal bin and me order another one :S

[Ian]

Wish I could help but the folks at www.v8engines.com are a mine of info on Rover V8's, try dropping them a line

[TerryG]

Pulled the crank out today, it doesn't look at all bad for a 150,000 mile engine with the last few having been in an off-road toy.
This is what the mains look like, all but the front through to the copper but no marks on the crank itself

mains.jpg (195.26 KiB) Viewed 1335 times

The big end pics are blurry so will post them when I take some new ones without an oily finger print on the camera lens. I was told it had poor compression on a couple of cylinders. This is because 7 and 8 the lower compression ring and oil scraper rings are stuck in the grooves on the piston, no movement at all, on 5 the upper ring is stuck in the groove.
Piston 1 has some "interesting" marks on the outside of the bearings

mark.jpg (40.4 KiB) Viewed 1335 times

I can't feel the mark but it doesn't look good. Maybe 1 new con-rod required

There is also some oily sludge inside the crank in the oil feed for 5/6.

I assume that checking the crank is OK is as simple as running a pair of callipers around all the mating surfaces and ensuring they are round and within the tolerances in the book?
All the bores look good, no lip just a bit of carbon at the top which comes off with a finger nail.

Does anyone know how do you check the small end bearings? Just force the gudgeon pins out with a punch and check the surface has white metal on it?

[kstrutt1]

The proper way is to remove them and get them checked with an internal micrometer, but as a rule of thumb if you can't feel any play and they are not scored etc they are probably OK.

If the pistons show any strange wear you may also want to get the rods checked for bending or twist, one of mine was twisted.


Kevin

[3xpendable]

For what its worth Terry, my 3.9 V8 had worn all the front main bearings down to the copper (but not the rear ones), this is usually a sign of low oil level. In my case the crank journals also had some grooving which required only 10thou grinding.

[TerryG]

I think I'm going to take this to have it cleaned and checked properly before I waste any time / money fitting new bearings and rings. I have a full new standard set so fingers crossed it doesn't need any grinding but I suspect it will need one of everything :S
It has over 150,000 miles on it so it's not overly surprising that there are some worn parts. Fortunately I have another good 4.2, a couple of 3.9s and a suspect 4.6 I can use to revive it if needs be. I may just have the crank checked and if it's good fit it to a 3.9 I know is good with only 70,000 miles on it to make another good 4.2.
Cheers guys.