2.8 versus 2.9
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Postmaster
Joined: Mar 2003
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From: Spokane WA
2.8 versus 2.9
Ive done two hours of research and havent come up with much, most questions seem to be about the 2.9, Ive gone all the way back to the beginning of this forum in 2002
I am looking at a couple of Bronco II's and am leaning towards the 2.8 motors as I have a few of each type available to me to buy, I need some info on the stock power numbers of the 84/85's and whether or not I should be thinking of the 2.9, but quite frankly Im not in the mood to mess with FI on something that has 200K on it, its too much work to maintain an older FI motor IMO.
post up guys, lemme know what you think, is the 2.8 an old gem, or a mistake that I shouldnt make.
what should a properly tuned and running 2.8 achieve for mileage in a 4x4 BII with a stick?
I am looking at a couple of Bronco II's and am leaning towards the 2.8 motors as I have a few of each type available to me to buy, I need some info on the stock power numbers of the 84/85's and whether or not I should be thinking of the 2.9, but quite frankly Im not in the mood to mess with FI on something that has 200K on it, its too much work to maintain an older FI motor IMO.
post up guys, lemme know what you think, is the 2.8 an old gem, or a mistake that I shouldnt make.
what should a properly tuned and running 2.8 achieve for mileage in a 4x4 BII with a stick?
Postmaster
Joined: Dec 2004
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From: Maple Valley, WA
chiltons says the 2.8l is rated 115hp/150tq, and the 2.9l is rated at 140hp/170tq. The 2.8 has alot more performance upgrades for it (four-barrel intake, duraspark conversion, etc.) but it gets terrible gas milege from what ive heard and it has a crappy oiling system with mechanical lifters you have to adjust. The 2.9 has alot more base power and has better built in features (bigger/better shaped ports, bigger valves, hydrualic lifters, etc.) but is limited to fuel injection and the less than fair amount of aftermarket equipment, not to mention the terrible head cracking problem on the 86/87 heads. Really its just a matter of taste. Personally I would choose the 2.9FI because its just a better engine, especially if its an 88 or up.
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Joined: Jan 2005
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The stock carb on the 2.8 is generally a headache. The feedback carb has electronic idle speed control and fuel mixture control. By 200k miles one that I had the engine had decent compression on three cylinders and when it rained the engine electronics did weird things, like race the engine at idle. I swapped blocks at 207k and put an autolite 2100 carb off of a '69 mustang's 302 on and using the jets from the ranger's carb got the fuel mileage up to about 23 mpg (it had been 19 mpg). The TFI ignition control modules on those engines tend to blow with some regularity but the 2.9 uses the same system. If you feel like converting to manual carb and duraspark ingnition the 2.8 is a decent engine. The solid lifters are not hard to adjust, and only need adjusting every 60k miles. If you want to tinker and tune the 2.8 is the better bet, mine always ran smoother than my friends with 2.9's but I had a lot more tinkering to do.
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Joined: Aug 2004
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From: Fort Wayne, IN
Originally Posted by RacinNdrummin
chiltons says the 2.8l is rated 115hp/150tq, and the 2.9l is rated at 140hp/170tq. The 2.8 has alot more performance upgrades for it (four-barrel intake, duraspark conversion, etc.) but it gets terrible gas milege from what ive heard and it has a crappy oiling system with mechanical lifters you have to adjust. The 2.9 has alot more base power and has better built in features (bigger/better shaped ports, bigger valves, hydrualic lifters, etc.) but is limited to fuel injection and the less than fair amount of aftermarket equipment, not to mention the terrible head cracking problem on the 86/87 heads. Really its just a matter of taste. Personally I would choose the 2.9FI because its just a better engine, especially if its an 88 or up.
. Pete
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Joined: Apr 2003
Posts: 779
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From: Tumwater, Wa
I've driven both in BroncoIIs with the same 5 speed, 3.45 gears, and same size tires on both. The 2.98 has a little more pull under 2500 rpm. I falls on it's face quickly after 4000. The 2.8 doesn't really start to pull untill 3000, but will wind untill you chicken out or the valves float.
I have a 85 BII with a 2.8. It has about 250,000 miles on it. It has lots of blow by, low compression, but starts every time, pulls down 15mpg now that it's an automatic trans, it got 18 with the 5 speed. The 2.9 only was rated 1 mpg better from the factory. Expect 18 for a good running one. After you do a duraspark conversion with a regular carb, you'll get bored with the 2.8s reliability. Oh, the valve seals tend to get crispy on the 2.8, but once you swap them for the viton replacements, no more start up smoke.
I'd look for an 84 BII with a C5 if you want an auto. They are the strongest tranny offered in the RBVs. If you want a manual trans, look at the 84s again. thye use the toyo koygo, which is a little stronger than the mitsubishi used in the 1985 and later trucks, though some later truck came with a toyo.
Good luck with your search.
Totalled from broncoii.org
I have a 85 BII with a 2.8. It has about 250,000 miles on it. It has lots of blow by, low compression, but starts every time, pulls down 15mpg now that it's an automatic trans, it got 18 with the 5 speed. The 2.9 only was rated 1 mpg better from the factory. Expect 18 for a good running one. After you do a duraspark conversion with a regular carb, you'll get bored with the 2.8s reliability. Oh, the valve seals tend to get crispy on the 2.8, but once you swap them for the viton replacements, no more start up smoke.
I'd look for an 84 BII with a C5 if you want an auto. They are the strongest tranny offered in the RBVs. If you want a manual trans, look at the 84s again. thye use the toyo koygo, which is a little stronger than the mitsubishi used in the 1985 and later trucks, though some later truck came with a toyo.
Good luck with your search.
Totalled from broncoii.org
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Joined: Dec 2004
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From: Maple Valley, WA
Originally Posted by pat67shorty
I'd look for an 84 BII with a C5 if you want an auto. They are the strongest tranny offered in the RBVs. If you want a manual trans, look at the 84s again. thye use the toyo koygo, which is a little stronger than the mitsubishi used in the 1985 and later trucks, though some later truck came with a toyo.
Good luck with your search.
Totalled from
Good luck with your search.
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