Hi, I have a good spare 4.0 bosch long block from a friends wrecked 2000 RR. I am wanting to completely rebuild it and have it ready to drop in an 04D2 project. It is a 95D 9.35:1 block (too bad it's not a gems block). None of the liners have hammered tops at the beveled area and I have cold pressure tested with soap and no signs of cracks. I plan to have it pressure tested at a machine shop and new cam bearings installed and maybe line bored, deck checked for flatness, crank polished and do the rest of the rebuild here. Main and rod bearings, rings, new cam and lifters, front and rear main seals, timing set, oil pump, rebuilt heads, etc. I don't want to sink alot of money into a good top hat lined block or anything like that, just want to build a good truck with a good rebuilt engine for $3k or so, less any bumpers, racks or lifts which I may add later.

What I'm wondering is should I put a 4.6 rotating assy in this block while I'm rebuilding? or just stay with the 4.0 assy? I could have it done sooner and ready to drop in if I stick with the crank assy that is in it now. Is there a big noticeable difference in 4.0 and 4.6 as far as power?

I don't have an 04 yet but am going to start on this engine and shop for a low miles 04D2 in good cosmetic condition that needs a head gasket job or something and swap this engine in. I see them needing engine work on CL in my area or 150 mile radius from time to time in the $1K to $2k range that look pretty good.
I'm hoping to find one at least running so I can check out the CDL and trans. also hopefully I can find one with all of the service records so I'll know kinda what I am getting.

I know it's kinda like building an airplane because I have a spare prop, but I want an 04 and I need to have another truck ready so when my 03 gives up the ghost and since I have this engine sitting here might as well rebuild it.

Just wondering if building up this bosch 4.0 is a good idea? or should sell it and find a good gems block?

And what year did disco start using bosch engines? and what years did RR use bosch engine? I have to keep all of my options open while hunting for a good deal on a good truck with a bad engine.

 

4.6 crank/rods & 4.0 pistons gives best compression and power.

My .02$, I'd use that block since you have it, put liners in it, 4.6 crank, 4.0 pistons, crower or DD cam, than rebuild/seal the rest. It's easily done for ~3k if you do it yourself. I have a block myself, I had the same plans until I started "more fun" project on the disco, so my rebuild will have to wait.

EDIT: Also, your 03 wont really just die, they only die when they overheat, or if the oil pump was let go for too long, so don't overheat it, or starve it of oil. Just rebuild your engine you have in your garage overtime so when the time comes, if it ever does, you can swap it in your 03. The only difference b/w the 03 and 04 is the T-case really, some oil pump issues also stemmed into the 04's as well, so just swap a lockable t-case in there and you have pretty much the same as an 04.

 

Thanks Dane, The 3K or a little more I mentioned is including another truck I plan to pick up for 1K to 2K, I am hoping I can do the engine rebuild for 1K to 1.5K in parts and machine shop work doing all the other work myself. Do I really need to put in new liners? if these are good? These haven't slipped but maybe I could pin them while I am rebuilding if everything else checks out? Flanged liners would take a big chunk of change alone and not sure I would trust just anybody to do that.

I just rebuilt my 03. Not totally rebuilt but did head gaskets, new timing set, new oil pump, new hoses, belt, thermostat, water pump, rebuilt drive shafts, resealed everything, and more but has near 150K and the paint is faded on the hood and roof and I had a tire separate doing 70 on the interstate and messed up the rear drivers quarter panel and rear bumper cover and my wife likes to run into stuff so the front bumper is cracked in the middle and on one side. I plan to keep it going and keep it up but don't know if I want to spring for bumpers and hood and quarter panel stuff like that. It's starting to look a little rough. I want to keep it but want to build a better looking and better ride altogether and keep this one for a beater to pull stuff around and pull my trailer and use it for a work truck. It serves alot of tractor duties pulling stumps and downed trees and anything that needs moving I drag it with the truck. I pulled most of a hundred year old barn down to reclaim the old lumber and timbers using this truck. So I work the crap out of it and it shows.

Anyway the prices on these trucks with engine problems are so cheap, I can pick up another truck for about what it would take to fix all the body issues I have on this one. Then I could just continue use this 03 as a farm truck and run into whatever without worrying about it. I really need two trucks. I figured out while doing my head gaskets and all of the other work that I need redundancy with these trucks. One to use while I work on the other. That way if one is down I'm not stuck without a truck.

I don't necessarily have to have an 04, I would buy another 03 since they go for even less, and I would like to have but don't just have to have CDL. and I could always add that later if needed. I will shop for the best deal on the best truck I can find for the money needing engine work (that's when they go for cheap). I will be looking for lowest mileage and with good trans and cosmetics as far as body and all.

So, sounds like a plan. What year did disco start using bosch engine? Did they have a year model that used bosch engine but no SAI? This engine does have SAI (bummer). If so, that would be a good year truck to find and then I could use non SAI heads on this rebuild. I hate all that extra stuff in the way. I'll have to find a truck that come with a bosch engine to make all of this as painless as possible.

Anyway, thanks for the tip on 4.6 crank and rods with 4.0 pistons. So how did you figure that out? That being the best comination? Just common sense from knowing these engines? or someone else built one using that combination? or?

 

So does anybody else have any input on 4.6 crank and rods vs 4.0 crank and rods in a 4.0 bosch block?
I looked around and don't see any 4.6 cranks for sale. I may have to use the 4.0 crank.

 

if you want to go 4.6 (i would) you need to replace the whole rotating assembly not just the crank, the rods and piston on a 4.6 are also different than a 4.0.
If the block pressure tests fine "i" would pin the liners in the block, before i started any build.
then have the block decked and squared as well as the heads, cam shaft bearing and a polished crank.

 

Ok, I plan to do all of the above.

I was reading on here and other places that I can use a 4.6 crank and rods and keep the 4.0 pistons? and get a little more power? You know anything about that?

Also read it's best to get line bored with new cam bearings. Have you ever had new cam bearings put in a bosch block? did you get it line bored? Is that something any good engine machine shop can do without screwing my block up?

I've read that I can use buick 300 finisihed cam bearings? I probably should print out all of the specs and tolerances and carry to the machine shop? or maybe machine shops know all that already? Maybe I should take them the new cam?

Also can a good machine shop pin the liners? I've read up on it and can do it myself but in the only write up I found on it the way it was done didn't look too professional and would make me worry about the pins/set screws moving in or out. I was thinking maybe it is a common practice and a engine machine shop may have a better way to do that?

Trying to get all of the input I can before I dive into this.

Also do you know where I can source a 4.6 crank and rods?
I guess if I buy an 04 I could take the crank out of it but, would be nice to have this engine finished while shopping for the best 04 or 03 or whatever I find.

Anyway, sorry for so many questions but, I'm anxious to get started on this and want to be confident in my decisions.

 

Ok, I plan to do all of the above.

I was reading on here and other places that I can use a 4.6 crank and rods and keep the 4.0 pistons? and get a little more power? You know anything about that? NO, "I" BELIEVE THAT THE 4.6 RODS HAVE AN OFFSET, IF THAT IS THE CASE THEN 4.6 PISTONS WOULD HAVE THE SAME OFFSET. BUT I COULD BE CONFUSSING IT WITH A 4.2.

Also read it's best to get line bored with new cam bearings. Have you ever had new cam bearings put in a bosch block? did you get it line bored? Is that something any good engine machine shop can do without screwing my block up? LINE BOARING AND CAM BEARING ARE TWO DIFFERENT ITEMS. YOU WANT TO HAVE THE BLOCK DECKED & LINEBOARD TO MAKE SURE EVERYTHING IS SQUARE AND TRUE. YOU WANT THE MACHINE SHOP TO INSTALL NEW CAM BEARINGS AS YOU NEED SPECIAL TOOLS TO INSTALL CAM BEARINGS.

I've read that I can use buick 300 finisihed cam bearings? I probably should print out all of the specs and tolerances and carry to the machine shop? or maybe machine shops know all that already? Maybe I should take them the new cam? YOU SHOULD BE ABLE TO USE LR BEARING. BRITISH ATLANTIC HAS THERE OWN BRAND OF IMPROVED CAM BEARINGS, YOU MAY WANT TO LOOK AT THEM.

Also can a good machine shop pin the liners? I've read up on it and can do it myself but in the only write up I found on it the way it was done didn't look to professional and would make me worry about the pins/set screws moving in or out. I was thinking maybe it is a common practice and a engine machine shop may have a better way to do that? THEY CAN DO IT, BUT THEY WILL TRY AND SELL YOU NEW LINERS, INSTEAD.

Trying to get all of the input I can before I dive into this.

Also do you know where I can source a 4.6 crank and rods? NO, BUT GET THE FLYWHEEL AND HARMONIC BALANCER TOO IF POSSIBLE. THEY ARE BALANCED AS A UNIT
I guess if I buy an 04 I could take the crank out of it but, was would be nice to have this engine finished while shopping for the best 04 or 03 or whatever I find.


AND USE GOOD FASTENER LIKE ARP STUD KITS

Anyway, sorry for so many questions but, I'm anxious to get started on this and want to be confident in my decisions.

 

You might find some interesting reading at these places.

Affordable Aluminum Buick / Rover Stroker Motor, by Kurt Schley

D&D Fabrications: V8 Technical Data

 

Ok I thought the cam bearing bore was line bored FOR the new cam bearings for a more square fit? I guess if they put in unfinished bearings they would have to line bore to finish the cam bearings? I guess I should just let the machine shop do what they do. I haven't had much machine work done before so don't know diddly when it comes to that but, yes will definitely get everything squared and pressure tested and crank polished and pin liners.
I have the tool and have installed cam bearings in SBC, but since I will have it at the machine shop anyway, I would rather let them do it since it is an aluminum block and since most of the cam bearings available are unfinished.

thanks again drowssap

 

Interesting reading! thanks for the links!