The Rover-Landers of BC

Putting the 3.9 together was so much fun last spring, I decided to get a 4.2 to build. I picked one up at the local yard this week. I pulled it out of a 1993 LWB. I won't know what it needs until I pull it apart. My plan is just to build it for longevity with the aim of capitalizing on the extra torque.

4.2's are pretty nice. More power than a 3.9, but not as lazy as a 4.6.
Still underpowered though... :smokey:
Post more photos of the rebuild!

I shattered my ankle, so it will be a few weeks before I can start in earnest. I ran the 3.9 down to eastern Oregon a couple of weeks ago fully loaded. I averaged 14.3 mpg on the highway and only about 9.7 mpg off road (mostly low range). There were a lot long climbs, and though the 4.2 is no powerhouse, I think the extra 30% torque will be just enough to carry the loaded truck over the passes at 65mph. :twisted:

Not really. Took the crowsnest, full throttle at 80kph. Always making you want more...

Ouch - maybe I should just send money to the Mark's adapter people now ;)

Just got my truck back on the road due to head gasket failure, and while I was at it, I replaced the lifters, and the cam with a crowler 29 cam. That old cam was deffenantly a drain on power, as it had a burn off loab. The new cam makes a huge difference, and really wakes the motor up. I managed to get the back end to step out while taking a corner! Much more even power throughout the range, and brings it up to a livable standard. I can now take the hill on 176th going into White Rock with the TQ locked up. :headbang: It's still slow, but less painfully slow.

The crower cams are a nice looking spec. Did you have any issues wit lifter pre-load? I have a new set of cadilac lifters I planned on using in the 4.2. I was planning on going with the 50230 grind rather than the 50229 - but they are very similar.

Can't say I've ever heard of anybody using caddy lifters, but it is from a GM I suppose. I soaked the lifters in a bucket of 5w-30 for 24 hours, and I primed the oil system for about 10 minutes using a drill. No lifter clatter. I also put in new oil pump gears, redid the relief valve, and gave it a double roller timing chain setup. Haven't driven it too much yet, but it seems to be a solid setup.

The caddy lifters are the same spec as the Rover 215 and 300. I used to use them in small block chevs because they respond better at low idle in long duration cams with the standard 1.5 rocker ratio. I've had this set sitting on my parts shelf since the 90's. Anyway, good to know you didn't have to add shims to the rocker shaft towers or go the adjustable push rod route. I'm hoping for the same, I'll measure it out when I get it installed in the block. I have another new double roller timing chain ready to go as well. The 3.9 has started with some low end knocking. It's mostly the rod bearings, but I figure I'll finish the 4.2 and refresh the 3.9 mains and rods for someone else to run before too long.

I have read on some websites that adding shims is necessary, but they're self adjusting hydrolic lifters, and it seems to run awesome, so I wouldn't think so. I'm sure those will work, as most chev stuff is hollariously good at being interchanged, but have you measured them to be sure? Are they genuine GM? Also, I don't suppose you have the part numbers off of those? I'd love to add them to my next build!

The set I have is NOS (new old stock) from the early 70s. The lifter bore is .842" with 0 offset. They were boxed up for the 472 cubic inch caddy engine from the late 60s. I doubt the caddies from that era ever needed new lifters. The pre-load is an issue on any engine with rocker shafts, which is one reason I've always preferred engines without them. I built a Ford FE block once I could never get the lifter tick out of.