I'm now looking into the crank and rods! I'll tell my machinist to hold off on polishing my crank. Do I need 4.6 pistons, or can I stick with my 4.0's? And will my ECU freak out with the change in displacement?

I already have all new parts you mentioned,too. new lifters, rockers, springs, rocker arms, upgraded water pump, new oil pump gears, and like you said, the list goes on!

I can rent a cherry picker here for $35/day that lifts 3tons and the boom goes almost 12' high. it's a large one that can reach into the bay. You may want to look into it for lifting a specific area in the back of the bay.

 

Nice rebuild you're doing, nice truck too! you should take that old ugly front bumper off....and sell it to me. haha.

I see all of the parts you are buying and looks like you are doing a great job!

I would like to know if you did your transmission overhaul yourself with the kit that you bought and how difficult of a job was that? Was it pretty straight forward with good instructions? I may need to know in the future.
And please spend ALOT of time reading and asking questions on the forum on installing your torque converter correctly. It takes several turns and clicks to get it seated properly with the last turn and push getting it to about 1/4" from the back of the bellhousing. There have been plenty of people wreck their trans from not having it seated properly. I know you are tuned in and pay attention to detail I can see that but, just a heads up on that cause it can do a lot of damage if not seated all of the way.

About the crank and rods. If it were me, first thing I would do before buying a 4.6 crank and rods is have your block pressure tested. Preferably at hot operating temp since a cold pressure test sometimes gives a false negative. I think a good machine shop can heat the block up to temp and do the test. That way if it has any cracks behind the liners they will open up when hot.
It's probably fine but, you would want to know for sure that it is fine before buying another crank and rods for your block.

Then if the pressure test is good, you may want to look into pinning the liners if you have the time and want the added insurance of knowing the liners will not slip in the future.
Now would be a good time to do that and there is a write up on it somewhere on the forum. I also have a pdf with a parts list if I can find it I will email it to you. Don't know if I can attach it to a PM. You can PM me your email address.

From all of the info I have been able to gather, the 4.0 pistons can be used and the crank and rods from a 4.6 is all that you need as far as the rotating assy. But I have also read that the cam in a 4.6 may be a little more aggressive so you may want a new crower cam. I see you have already bought a cam so, you would have to research if the cam you bought would be ok with a 4.6 crank assy. and you really should get new cam bearings put in. I have read that buick 300 cam bearings will work and they are only like $40 compared to $150 to $200 for finished rover bearings. You will have to do more research on that. The machine shop should be able to measure the buick cam bearings before they install them to be sure they will work with you cam and if they will not you could return them. Keep me posted on what you find out on that.

You may be able to get up with member ptschram and find out for sure if the 4.0 pistons can stay and to get more info on pinning the liners. I think he says he does it on all of his rebuilds and he has rebuilt hundreds of these.

Some people will tell you to get top hat flanged liners, but that will run you $1500 or more installed and if you are trying to do this without breaking the bank, you can just pin the liners.

And I'm sure tens of thousands of these have been rebuilt without pinning or resleeving, so that would be your call. Pinning is cheap if you do it yourself and parts for the job are only $30 or so total.

And no from what I have read you will not need to change the ECU or BCU to swap from 4.0 bosch to 4.6 bosch. They say that it is a painless swap and the computers will adapt on their own with no problems.

and if you have already bought main and rod bearings and they are STD be sure the crank you buy will be good with only a polish and doesn't need to be turned. Make sure whoever you buy it from guarantees it will pass a magnaflux for cracks and that it doesn't need turning/ grinding so you can use the the new bearings you have already bought.

If the swap ends up being more than you want to spend, you could always just stay with the 4.0 crank setup and still have a very nice truck. Depending on what you plan to use the truck for you may be fine with the 4.0. It may not be worth it to you for the added .6L

If you do swap it out you could sell your other crank and rods and get a good bit of your money back that you spend on the 4.6 crank. As good as you are at sourcing parts, you may be able to get a complete 4.6 engine for cheap and use the crank/rods from it in your block and keep all of the other parts for spares or fleabay them.

I'm following you rebuild and good job with all of the pics. Keep up the good work.

BTW I am new to this too and although I have had a rover for 8 years, I've been lucky that it has not had any major problems other than head gaskets and such. So as far as major work,I'm learning as I go and most of the info I have gathered has been from this forum and others. Just passing along what I have read.