Engine questions

[TerryS]

Originally Posted by Elemental

4.2 with a better low end cam cost me $2000 to do mine.

I think I did the 4.2 in my 110 for almost the same $. Would have been a bit less, but the machine shop charged me way more than the going rate. Had all the plugs pulled, the block boiled,decked it slightly, and he installed the cam bearings. Got FM bearings and rings on-line. The cam I used had a bit more lift, but rather than trepan the spring pockets, I bought flat wound springs from a diesel shop.

Army, a 3.9 is a bored 3.5, and a 4.2 is a stroked 3.9

[hermanpj]

Elemental (Chris?) could you go so far as to get 4.6 out of a 3.9 by putting 4.6 crank, rods and pistons in it? Or is 4.2 the practical limit without changing to a more recent engine block?

Did you change the chip when you went from 3.9 to 4.2?

Assuming one would have to replace engine managment chip or the whole EFI computer to get useful power out of the upgrade - would doing this cause problems w the OBD / multifunction display unit.

[Elemental]

Originally Posted by hermanpj

Elemental (Chris?) could you go so far as to get 4.6 out of a 3.9 by putting 4.6 crank, rods and pistons in it? Or is 4.2 the practical limit without changing to a more recent engine block?

Did you change the chip when you went from 3.9 to 4.2?

Assuming one would have to replace engine managment chip or the whole EFI computer to get useful power out of the upgrade - would doing this cause problems w the OBD / multifunction display unit.

THe 4.0 and 4.6 Crank is too large for the journals. You COULD transplant a 4.6 into a 3.9 block with a bunch fo machining that just wouldnt make sense.
Also, the 4.0 is the same bore as 3.9/4.2, but the 4.6 pistons require a larger hole.


I did change the chip to a 4.2 chip, but when I had the 3.9 prom in it ran just fine.. I changed it to address a cold start issue. You could use the 3.9 prom without any problems or concerns in my experiance.

[hermanpj]

got it - thanks!

[TerryS]

Pat, as Elemental says, you can't use a Bosch crank in anything but a Bosch block. Those engines are 4 crossbolted main bearing engines and journal sizes are not close.
If you really want to get fancy, look around the speed shops for the buick 300ci aluminum block engine. It will bolt right in. The best thing about that engine is that there are six headbolts surrounding each cylinder, so you can really dial up some rediculous compression ratios. (can you say 4 Webber 45DCDE ? I think I'm getting a hardon) I've got a 6 bolt buick 215 & heads stashed for when I have nothing else to do.
I have a scored 4.2 crank available to me, but I can probably get another 4.2 engine for less money than it would cost to grind it.
RPI and ACR build the old block engines out to 5.6 litre, and there were a bunch of TVR 4.3 engines around awhile ago (new, longblocks) they were being sold as 4.2s but the numbers say they were the 4.3 (same stroke as the 4.2, slightly bigger bore.) There were also 4.5 TVR engines.

[TerryS]

Get This book and read the parts on MGB. Then call your banker.

Weber Book on Tuning and Theory by HP Books

[ArmyRover]

To bad you probably couldn't retrofit the fuel injection to that 300 buick now that would be a sweeeeet set up.

Hmmm maybe I need to look around for one of these fabled old buick 300's lol I really would love more power.

[hermanpj]

I have to say I am just continually impressed by the caliber of knowledge I find in the contributors to this forum. Really solid. This started as Army's post but I'm learning a ton from it!

So... my 3.9 has 195,000 miles on it. Runs pretty well, but at some point I will be proactive about overhauling the engine and at that time I'm going to want to upgrade. I hadn't even thought of going all the way back to those Buick engines that originally came over to Land Rover. That's genius, but then I'd guess you'd start running into the same kind of costs as a new 4.6 engine or perhaps much more.

Like Army I thought about GM or Ford diesels and thought about a Chevy 350, but then you start turning your Land Rover into a Frankenstein-car. I'd rather stay with a Land Rover engine. If I stumbled across a 4.6 at a decent price I'd snatch it up, but to be honest staying with my own engine block - the heart of the vehicle - seems like the best idea. It's done 195,000 miles, and while it will need some re-conditioning, its in good shape. I think getting her up to a 4.2 would be plenty power. I do plan to do axle and differential upgrades, swap out the Borg Warner for an LR center dif with a locker, and ultimately to run some larger tires. So a moderate power upgrade is going to be needed. One thing at a time.

[Elemental]

Originally Posted by ArmyRover

To bad you probably couldn't retrofit the fuel injection to that 300 buick now that would be a sweeeeet set up.

Why couldnt you? Wouldnt be a big deal really.

[ArmyRover]

I was figureing that there would be mating issues but the search is on for the old buick motor that sounds like the most fun choice lol plus a little more displacement never hurt anyone.

Also going off of the drop in status of the 300 ci buick wouldn't the 340 buick be in the same category?

[TN-LR3]

The rover route would be do a 4.2L and build it up slightly with 4.6 parts, someone makes a cam upgrade I think? along with headers and port and polishing the top end. That would be a sweet motor! Thats what I would do!

A small block chevy would be cool but could add up if you do EFI, but parts are cheap and easy to find...... I would personally do this with a LT1 because they are already EFI and are powerhouses to begin with.

And if you are going for a diesel, a cummins 4bt out of a delivery truck would be sick.

I would love to drop a 4BT in my 92' RRC because I love the 5.9L in my dodge, but I would need some bigger axles to take the torque.

[ArmyRover]

Well doing a lot of reading on the old buick v8's it does seem so far that the 215 300 310 and 340 would all be a direct swap in except for maybe a line up issue off the crank but it was said there is enough slop in mounting of a auto trans to take up the minor difference.

The big difference I have found besides aluminum and iron is the 300 has a higher deck height so I don't think the FI set up would swap directly over.

I'm still reading though.


Oh and the cummins would be the cats ass but I haven't found jack on doing the swap.

[Supernatural]

57LB Check your Pm Thanks..

Originally Posted by 57loboy

I have a good 4.2 from a '93 missing only the distributor for sale for a good price...let me know if interested, I am in CT

[ArmyRover]

Well the research continues on the buick V8 family I can't seem to find a straight answer as to the bell housing being the same some say yes some say no. That's what I need to get confirmed.

You would however need adaptors to mount the FI system to the 300 or 340 as the intake manifolds are wider than the 3.9's.


First Post! 1 quick one long question. Thanks - V8Buick.com

[TN-LR3]

Someone makes a stroker kit for a 4.0/4.2l that makes it a 4.8. Someone also wrote up on how you can use a 4.2l block with 4.6 crank and stuff


If you want a powerful v-6 that is also a small buick engine (3.8), the motor from a grandnational would be sick. If you have ever ridden in one, they are fast!!!!