2001 4.3 Vortec

[jimoshel]

How hard would it be to swap a 2001 4.3 Vortec into a '86 MJ with a busted 2.8, 5sp 4wd? I know it's a 90* vs 60* but don't know how the bell housing bolt pattern is. Got a chance to pick up a low mileage , cheap 4.3 is the reason for the question.

[1987Comanche]

  Best place to gather ideas would probably be an S-10 forum.  The first gen S-10s had a 2.5 4 banger, the same 2.8 as in the MJ, or the 4.3.  If you can determine what manual came with the 2.8 and 4.3 S-10 it should give you an idea of bellhousing pattern.  I'd imagine a lot of people have swapped the 2.8 for either the 4.3 or SBC 

[mnkyboy]

The 4.3l is basically a 350 with 2 cyls missing so it uses the SBC bellhousing.

 

Most people swap the engine and trans as a unit but you can get an adapter to adapt it to an AX15.

[jimoshel]

An S10 forum? That must be why i never thought of it. To obvious. :thumbsup:

[xjrev10]

XJtalk also.  There is a guy on there, 4.3LXJ or something like that.  Hes one of the admin guys.

[mnkyboy]

I've done a bit of research on it as I'm just starting a 4.3l swap, basically no part of the swap is bolt in. Unless you really wanted a 4.3l a 4.0l would be a much easier and much less expensive swap.

[jimoshel]

I would much prefer a 4.0 but the possible clearance problem is why I.m holding of on going that route. I have perfectly good low mileage 4.0, AX15, 231 in a '95 Xj I'm parting out. Maybe I'll go uot tomorrow and do some measuring. As much as I hate the idea, maybe a little tap on the firewall just may be the way to go.

[mnkyboy]

That's kinda my situation. I have two 4.0ls sitting in the shop but a 4.0l won't fit my engine bay.

[jimoshel]

Yeah. The thing is , Ive also got a '91 and a '93 2.8 out of a S10. I could drop one of them in with no problem and be on the road in a day. Just looking for a little more ooomph and reliability.

[JeepcoMJ]

in no way would the cost of the 4.3 be worth the hassle.

 

you can literally do a 350 swap for the exact same cost. and no offense to anyone with a 4.3, but they don't hold a candle to a 350 in reliability, economy, or overall value. I've seen some with miles, but they cost more than the vehicle's value over their entire lifetime.

[MJ_Milam]

try this site they usually have products for engine swaps

https://www.novak-adapt.com/catalog/engine_mounts/engine_mounts.htm

[mnkyboy]

Other then the CPI or spider injection years they seem to be pretty reliable. Not sure why a 350 would be any more reliable since other then number of cylinders they are almost identical.

I've seen many of them in the 300,000 mile range with very little work if any done to the engine itself.

[mnkyboy]

try this site they usually have products for engine swaps

https://www.novak-adapt.com/catalog/engine_mounts/engine_mounts.htm

Advanced adapters also sells a lot of stuff for the swap too. If you had the cash there is enough conversion parts available to make the swap pretty simple.

[JeepcoMJ]

spider injection and the fact that v8's and STRAIGHT 6's and 4's naturally balance.....v6's do not. the crank in a 4.3is counterweighted more in some areas than others to balance it out. not a fan

 

4.3 won't get the mileage you could get with a 350. power to weight, cost for cost, and economy, you are better off with a 350

[mnkyboy]

I will have to see how my swap goes. I'm using a TBI 4.3l so no spider injection and I'm hoping the 4.3l will be easier to keep cool then the 350. It should also get decent fuel mileage and hopefully be less destructive to my light duty axles.

 

I figure worst case once the 4.3l is running in the truck it would be easy to swap for another SBC bolt but I think overall it should be a good engine in the MJ.

[JeepcoMJ]

as far as gas mileage, the 4.3 will get the same or worse than a 4.0

 

the 350 cools darn near the same as a 4.3. put a pusher and puller fan on and be done...

[mnkyboy]

I'm currently running a 4.0l open system radiator with dual E fans, I'm also planning to rework the shock towers to allow more air around the V block so hopefully it will stay cool.

 

My 2.5l gets about the same mileage as a 4.0l so it would be cool to almost double power output and retain similar gas mileage.

[jimoshel]

Sure glad I got a half dozen vehicles to drive so I don't have to make a quick decision on this.Appreciate all the input Pat an Mnkyboy.

[Bounty Hunter]

The 4.3L does have good attributes over the 350.  There's a lot to be said for lighter weight and more room to work on an engine.  The 4.3L is a compact powerhouse and what I plan on putting in my '89 MJ.  I have the Blazer harness and ECM, I'll have the harness stripped to the bare necessities and the ECM reprogrammed. 

[JeepcoMJ]

is it lighter?   yes.    But there is no issue with space with a 350.   on the whole, the biggest issue is radiator clearance...whih 99% of cars have anyways.

 

and at least with a 350, the oil filter isn't as hard to change as something like a jeep liberty or other b.s. like that.

 

 

Jim, it's a custom swap.    may as well make it cool and put a 350 in.    a 4.3 is not cool.

[gogmorgo]

The power numbers of the best of the 4.3's are similar to a 4.0 HO, and are likely just as reliable. Go to any utility company still running Astro vans (out of production for  and they'll tell you what's up. As has been mentioned, it's pretty well just a 350 without two of the cylinders. It'll have no issues going into the engine bay so long as you've got bolting it up covered, which shouldn't be much of an issue due to sbc swaps being as common as dirt. If you can get one out of a half-ton or full-size van, it'll be a tad stronger. For some reason the '02-03 full-size engines had higher output, but after '03 the numbers go back down again. Might want to find out why.

 

In terms of cool factor, sbc swaps may have been cool 20 years ago, but now they're overplayed. No matter what mass-produced vehicle you're looking at I'm sure someone's swapped a 350 into one of them. Personally, I think the 4.3 would be much more cool.

 

Also, inline engines don't naturally balance. 90° V8's barely do. I6's can be made to balance by mirroring the cylinders, which puts a lot of stress on the crank. I4's don't even come close to balancing, so they need to use a balancing shaft, as do V6's. It might sap a little power, but it's more reliable.

[MJ_Milam]

The power numbers of the best of the 4.3's are similar to a 4.0 HO, and are likely just as reliable. Go to any utility company still running Astro vans (out of production for  and they'll tell you what's up. As has been mentioned, it's pretty well just a 350 without two of the cylinders. It'll have no issues going into the engine bay so long as you've got bolting it up covered, which shouldn't be much of an issue due to sbc swaps being as common as dirt. If you can get one out of a half-ton or full-size van, it'll be a tad stronger. For some reason the '02-03 full-size engines had higher output, but after '03 the numbers go back down again. Might want to find out why.

 

In terms of cool factor, sbc swaps may have been cool 20 years ago, but now they're overplayed. No matter what mass-produced vehicle you're looking at I'm sure someone's swapped a 350 into one of them. Personally, I think the 4.3 would be much more cool.

 

Also, inline engines don't naturally balance. 90° V8's barely do. I6's can be made to balance by mirroring the cylinders, which puts a lot of stress on the crank. I4's don't even come close to balancing, so they need to use a balancing shaft, as do V6's. It might sap a little power, but it's more reliable.

the 4.3 vortec doesn't use a counter-balance shaft because they have a splayed crank shaft and I-6 cranks are balanced, they are 120 degree cranks.

[mnkyboy]

As far as I know, all 92 and up 4.3ls have balance shafts.only the 86-91s didn't have them.

[gogmorgo]

the 4.3 vortec doesn't use a counter-balance shaft because they have a splayed crank shaft and I-6 cranks are balanced, they are 120 degree cranks.

Depends on what you mean by balance. The longer crankshafts of inline sixes and up flex with each combustion stroke, enough to throw off the balance of the engine setup (i.e. pistons moving in pairs). At the right (er, wrong) rpm, the torsional vibration can resonate and stress the crankshaft enough that it fails. But your engine is not likely to stay at that precise rpm long enough for anything to happen to it, and I shouldn't be arguing after midnight...