What to put in the Tux

Sorry Lynn, didn't see your post when I did my reply! By the way, aren't you the one that recommended this site? Thank you, everyones been very helpful!

 

Now that I've been rescued, you guys are going to have to deal with all my newbie questions!

 

Ok, I knew there were fans of the F4 here besides Billy. Didn't mean to raise anyones hackles, but there are some negative aspects of the F4 that cannot be denied.

The power-to-weight ratio is worse than 20:1, even in best of circumstances. Most drivers today would find this unacceptable. Horsepower is the product of RPM and torque; having an engine that is so rev limited as the F4 really limits the power it can make.

It's an orphan. The engine was only used in Jeep or Kaiser vehicles, and production ended in 1971. It would be hard to find one of these that is not really tired and is not being used in a Jeep.

The engine is very heavy compared to more modern engines. I'd guess you save 300# of unneeded iron by using a Pinto engine. You probably save 200# with a V6.

On the positive side, it does have a forged steel crank, forged steel rods, and a very long stroke. The long stroke means that it has lots of torque at very low RPM. It also means that the piston velocity becomes very high at higher RPM and that puts a lot of stress on the rod bearings. I'd deduce that this is why Jim stresses oiling and overheating - because the rod bearings won't tolerate anything less than 100% oiling for any length of time. Thin oil (hot), wear, or low oil means you're going to burn a rod if you push the RPM.

Just food for thought - not meant as flame-bait.

 

Gotta agree with Tim somewhat . If I had a good running 134 dont know if I'd pull it cause they are JEEP engines. But if I didn't have an engine in it.... I aint gonna put one in it. As far as power to weight issues can't beat the Buick V6(225-252) easy to work on plentiful in the wrecking yards. One that hasn't been mentioned is the Iron Duke 4 either the 69 -older chevy II engine or the 2.5 Pontiac version that was used in GM vehicles and CJs before 83. This engine can run at hyway rpm with no problem is easy to get 100 to 120 hp out of and are cheap when you find 'em. Even still they are about the same weight as the Buick V6 which you can get double the hp relitively easy and inexpensively.

 

Heh heh. ... "Really? Tell me more!"

 

Ah, yes we have! "Pontiac 151 I4 (used in the Fiero and Cavalier), Chevy 153 I4 (used in Novas and postal Jeeps)" - see above.

It's not clear to me which engine is the real "Iron Duke" - I think maybe the Pontiac/Cavalier engine. The Chevy II engine is derived from the Chevrolet 230cid inline 6 (which also came in the 194 and 250cid sizes). It uses lots of the same parts as the 230; pistons rods, etc. 230/6 * 4 = 153. You can identify it by the tall, square-cornered valve cover, and by the manifolds, which are both on the drivers side. It has a bored-out brother, a 3.0L marine engine (181cid) sold by Mercruiser. The 153 was popular for midget racers in the past, and also came in some postal Jeeps.

The 151 that came in CJ Jeeps is a cross-flow engine (I believe) and has a very different valve cover. This engine can be really cheap, since in it's stock form it's kind of a cigar butt of an engine. There's nothing wrong with it other than its not very glamorous. I recall the version to get is the one that came in S10s.

I believe both these engines have the Chevy bell pattern, and can use the common long-input T-90 GM adapter with a Chevy bellhousing.

 

as i have been told by some people. you can get that motor and put a GTO head on it since all that it is half a V-8.
this might not be true but it is one of those things i was told when i was looking for a CJ years ago.

 

There is a Super Duty head for it helps it breath which is one of the maladies it suffers from.The other it's unwilliness to rev past 5 or 6 thousand rpm. But then it's quite happy at 3 to 5 and does it with a good low end. No not half of a V8 2/3 of a 6.

 

see i told everyone i didnt know what i was talking about

 

Well it seems to me you have been given alot of info on the motor portion, (I still think bigger is better, see signature below) But if you use anything with any real power at all get rid of the t86 transmission. they dont hold up well. I have trashed 2 of them when I had my dauntless motor and I dont really consider it a high horsepower, or high torque engine by any stretch of the word. If you want to drive like an old lady it will be fine, but I like to get on it a little bit now and then, and dont like having the transmission as my weak link. Now I dont try to spin all 4 tires on pavement , that would be stupid, but I do drive it hard mostely in the sand dunes and can tell you by experience they dont hold up well to offroading. Please dont anyone take this as me busting on their equiptment, just trying to educate others from my experiences.Keep Jeepin'

 

Regarding the T90/T86, yeah, they aren't the strongest transmission you can choose. However, they will stand up to more power if you treat then right. By more power I mean the stock 4 and 6 cylinder engines discussed here.

IMO the T90 will be ok if you don't try to shift too fast (the Borg-Warner 3-speeds require slow, deliberate shifts), and don't try to shift with too much throttle (no impact load). If this defines "driving like an old lady", then so be it.

In the past, there have been plenty of T90s that were converted to run with small block Chevys and Fords. A very common swap was a SBC in an early Gladiator pickup or Wagoneer that came with the 230 OHV inline six. These vehicles were cheap even by the early 70s because everyone (maybe a little unfairly) hated that engine.

The main difference I observe between then and now is tire size. Most of these conversions were running stock or slightly oversize tires. Today, tires are much larger, which in addition to providing more traction, also are much heavier. Under such conditions, a T90 is probably the weak link.

Chris mentioned sand dunes - that probably means trying to shift fast with a lot of throttle. I can understand how that could be hard on a transmission. In the heyday of T90-SBC swaps, the sand dune guys typically ran T-10s, not T90s. A close-ratio 4-speed makes much more sense for this kind of use.

Today, the truck 4-speeds (T18A, SM420, SM465, NP435, a few others), with a granny first gear, are very popular. They are both strong and provide impressive gearing. They are probably the cheapest and most practical way to get a really high "crawl ratio" and still have streetable axle ratios. They are not good at shifting fast though.

Compared to the T90, these transmissions are both large and very heavy. Adapting to an engine is easy, because you can pick the transmission the engine manufacturer originally supplied with their trucks. Mating the transmission to the transfer case is generally not easy and cheap.

IMO installing a new drivetrain cheaply and easily means you either have to be very conventional about the choice of drivetrain, or else you need to have a lot of knowledge at your disposal. Conventional means using as much of the stock drivetrain as possible, or at least doing the same thing as what others have done in the past. I can imagine other drivetrains that might work well, and would be cheap. You'd have to choose components that others don't want. For example, lots of the GM 151 and AMC 150 4-cylinder engines are coming out of Jeeps in favor of bigger engines. I believe these use the same bellhousing as the T-150 transmission, although the bell will need to be redrilled. The T-150 is another component that's not highly sought after, and has a Texas pattern, so you should be able to mate it to a Dana 18 or Dana 20. Voila - pretty-good engine, transmission and transfer case; modern by Jeep standards, and sturdy.