XR4 vs. XR2

[rochelle howell]

I thought the same thing

[j_martin]

I bought an XR4 about 10 years ago, pretty much stock. After I cleaned up all the careless tune work on it, did a little Dremmel work on the stator mount to get full timing, and discarded the timing modules, I had to go buy a new prop 4 inches steeper. It's been a sweet, strong motor for years. I figure it's running around 175 HP at 5200 rpm.

[croSSed]

yes!

In fact the XR2 already has the 200 bell tuner in it. It will help relieve the restrictive exhaust in the XR4.

The XR2 was a hot rod 2.0, XR4 and XR6 were choked down 2.4 and 2.5 respectively.

I always figured the XR2 was a factory hot-rodded 2 liter 150. It certainly runs that way. I call it "pissed off."
The reason I say it would be easier to do a powerhead swap is because my XR2 has solid mounts and hydraulic steering. I'd have to disassemble both mids to get the solid mounts swapped over, and the install of the hydraulic steering is just a little more involved than dual cable.
The XR4 does have the little 1.78:1 lower. That has to go. I'm going to run my XR2's 2:1 lower that already has the top 3 holes plugged for high running.

I have ANOTHER question for y'all: Can I turn that 2.4L motor over 6 grand if I premix oil at 40:1? I guarantee that's what will happen. I'm spinning a 27P Laser II with the 2 liter at 6 grand now. I expect the XR4 (if it's in good shape) to go higher than that.

[nitro_rat]

Yes the XR4 will have no problem turning 6k. Ditch the oil injection and premix. You'll probably want to find a 2.4 200 1.87 lower.

[TEXAS20225]

i know all about sleeves spinning in the early xr4 and so do a lot of us older guys i spent a load of money on these poorly machine blocks the offset between sleeve and registers was not enough and they spun and quite often,they were also way too thin walls on registers i tried various patches on them to keep them from doing this after spending way to much i just moved on to bigger and better stuff get in touch with James Perry (wrenchi 2 )he likes the fat block 2/4 they are so much better he will give you a history lesson on them!!!! tlwtkw knows exactly what he talking about on this moto rbut he is a old guy like me and has lots of experience with merc BS machine work

[croSSed]

i know all about sleeves spinning in the early xr4 and so do a lot of us older guys i spent a load of money on these poorly machine blocks the offset between sleeve and registers was not enough and they spun and quite often,they were also way too thin walls on registers i tried various patches on them to keep them from doing this after spending way to much i just moved on to bigger and better stuff get in touch with James Perry (wrenchi 2 )he likes the fat block 2/4 they are so much better he will give you a history lesson on them!!!! tlwtkw knows exactly what he talking about on this moto rbut he is a old guy like me and has lots of experience with merc BS machine work

Hmm. This makes me extremely reticent to make an offer on this motor.

[j_martin]

The XR4 does have the little 1.78:1 lower. That has to go. I'm going to run my XR2's 2:1 lower that already has the top 3 holes plugged for high running.

I have ANOTHER question for y'all: Can I turn that 2.4L motor over 6 grand if I premix oil at 40:1? I guarantee that's what will happen. I'm spinning a 27P Laser II with the 2 liter at 6 grand now. I expect the XR4 (if it's in good shape) to go higher than that.

I like the little lower. It's pretty slippery. If you don't set it up right, or try to surface pierce with a 3 blade, you'll put parts through the side. I have run a high five surfacing for years with no trouble. On a fishing boat sometimes the grappling power of this prop gets real important, in rough water for instance, or turning pulling a water ski. Usually run a 26" at about 5200 rpm. Go to a 24" 5 blade for pulling or a heavy (camping in Voyagers for instance) load.

[David]

I ran a 1990 XR4 for 20 years. Other than blowing up 3 or 4 gearcases (surfacing) it was a great motor. It did not want to turn more than 6000 rpm, but I still had the factory ignition retard. It turned a 31 Triton on my SS2000.

[croSSed]

I like the little lower. It's pretty slippery. If you don't set it up right, or try to surface pierce with a 3 blade, you'll put parts through the side. I have run a high five surfacing for years with no trouble. On a fishing boat sometimes the grappling power of this prop gets real important, in rough water for instance, or turning pulling a water ski. Usually run a 26" at about 5200 rpm. Go to a 24" 5 blade for pulling or a heavy (camping in Voyagers for instance) load.

The whole reason for wanting the XR4 is for the extra torque. If I run the 1.78 lower all that goes out the window. Plus, I'd have to spend money on small gear case props.
nitro_rat: Why would I want to acquire a 1.87 lower over the 2:1 lower that I have?

[TEXAS20225]

IMHO 21 1S TICKET ive owned a 95 Bullet since new ive had 29 motors on it ive(because i could)never kept any motor 20 years david u are talking about a tree im talking about the forest i rebuilt motors for a living 90 could be fat block which is miles ahead of the first one



T

[FORBESAUTO]

The whole reason for wanting the XR4 is for the extra torque. If I run the 1.78 lower all that goes out the window. Plus, I'd have to spend money on small gear case props.
nitro_rat: Why would I want to acquire a 1.87 lower over the 2:1 lower that I have?

JMO, but stick with 2:1, you won’t regret it.