High speed for a Series?

**sayers** · 01-10-2008, 04:51 PM

I have a 74 88 and about 50-55 is all mind will go, so you are doing well at 60. I don't think that driving at that speed for short distants will hurt the engine, but remember these truck were made for rough terrian driving at slow speeds and not the american highways. adding an overdrive unit would really help in engine wear. good luck.

**PH4** · 01-10-2008, 05:07 PM

Drove it 5 1/2 hours yesterday at 55mph. Slightly more quite than riding in a helicopter, slightly. I will eventually put an overdrive in but for now I am stuck with stock. If motors have trouble pushing 60mph now am I really going to get a much higher speed out of an overdrive?

**Jim-ME** · 01-10-2008, 05:17 PM

An overdrive isn't really suposed to give you a higher top end. They were designed to reduce wear on Series engines and give a little better mileage as well. You can go faster at your top end rpms but from one who pushed a Series Rover from CT to ME evey other weekend it was the long distance higher rpms which lead to an earlier demise of my engine than I would have liked.
Jim

**greenmeanie** · 01-10-2008, 06:05 PM

Well on my 71 IIA 88 with 30 X 9.5 rubber and a Roverdrive the speedo tells me I can push her up to 70 mph. I think that given the realms of scientific measurement error in a Rover speedo that it is more likely to be 65 mph in reality. The engine was mildly breathed on with Turner head, 2.5 cam, Rochester, K&N and electronic ignition.

I used to do 1K miles a week like this on the I10 between Phx and Tucson. I wouldn't say I could beat any land speed records but it was fast enough that I could happily rumble along with the big rigs in the inside lane. You still slow down on long climbs. If you stay on top of your maintenance and your revs below 4K the engine should be just fine on the freeway - if anything giving it a good blast helps blow out any carbon build up.

My bank manger will tell you that trying to push a series along at high rpm or high (relative here) speed will trash your originally naff fuel consumption.

Cheers
Gregor

**ChrisB** · 01-10-2008, 06:29 PM

I have a '70 IIA 88 with a Fairey O/D. It tops out at 60 mph going downhill and with a tailwind. Drove it from Vero Beach, FL to Birmingham, AL recently, and I felt like I had just driven a stagecoach 750 miles. I also just regained my hearing from that experience.

**O'Brien** · 01-10-2008, 06:35 PM

i've got a chevy 4.1L straight six in mine. with the overdrive, i manage 75 on the freeway in my 109 stationw agon no problem. the one long trip i took (driving it home from the previous owner when i bought it) i kept it pegged at about 65 the whole way, then mid 50's over the grapevine here in southern california

**PH4** · 01-10-2008, 06:50 PM

A larger engine (especially a Mercedes Diesel) is tempting but for me I really like to keep my Series as stock as possible. I did install parabolics on one and will put an overdive in one day but I think that is about as far as I will go other than maybe some performance mods to the 2.25. I think many of the modifications you can do to a Series are great but I like/need to keep it simple.

I am curious in regards to those who have 2.25s in the mountains and hills. I am in dead flat land and always wondered what it must be like trying to get one for a length of time up a hill at speed.

**Jeff Aronson** · 01-10-2008, 07:09 PM

My '66 II-A with at least 300,000 miles on a rebuilt engine has been run with and without the overdrive. As noted above, the overdrive does not increase final speed. It just increases the final drive ratio so that you will go down the road with more reasonable mpg and decibel level.

The Rover 2.25 makes a lot of noise but it's actually only running about 4,000 rpm when you "put the pedal to the metal." On my Rover, I can do 60-65 without overdrive, 70 downhill. With the overdrive engaged, it runs at the same speed but sounds different.

As for hills, they will reduce my top speed on interstate climbs, or back road inclines. The overdrive is actually helpful there as it gives you an "intermediate" gear for upshifts without losing as much speed. When my previous engine was very tired, I would slow down to 40-45 on interstate hills in northern New England. With the current engine, I find myself slowing down only to 55 or so on steep interstate hills.

A properly maintained engine [oil changes, tappet adjustments, point adjustments and replacements] will last a long time. Highway running has not weakened my engine over hundreds of thousands of miles.

As an aside, I run a Weber carb, which does run lean. My other II-A has only 46,000 original miles and the original Solex. It has better acceleration and on a trip from Vermont to Maine, maintained 55-60 mph on hilly, two lane roads.

Hope this helps!

Jeff

**ChrisB** · 01-10-2008, 07:39 PM

I am curious in regards to those who have 2.25s in the mountains and hills. I am in dead flat land and always wondered what it must be like trying to get one for a length of time up a hill at speed.[/quote]

I have a rebuilt 2.25 and run a Weber carb. Birmingham is very hilly and my IIA accelerates "ok" uphill, but as you might imagine, I am not winning any races around here.

**LaneRover** · 01-10-2008, 07:52 PM

My 1969 109 p-up with a ex-mil rebuilt motor and an overdrive cruised across the country at about 70.

I have had my 1965 109 SW up to 72 with no overdrive and it will cruise at 60. Of course it LOVES 45-50 on back roads the best.

They both see the hills before I do and will slow down accordingly. The P-up is no where near as bad as the SW though.

Brent

**yorker** · 01-11-2008, 03:32 PM

I can ram around at 65 most of the time- that hs with a tired engine block but new head and 2 barrel Weber. Hills kill it and it of course prefers 45-50 MPH. I don't think I'd dare use it on the interstates here, the slow vehicles here seem to be going 70-75 and with all the nutters on the road the 88" just seems like an accident waiting to happen. When I rebuild the Ambulance it will have something with enough power to get it both into and out of trouble.

**Bostonian1976** · 01-11-2008, 04:11 PM

Hmm - I think my Rover can easily do 65-70....it just screams when it's doing it. My normal speeds are 55 or so. It doesn't slow down too much on hills either.

Plenty of power - unfortunately plenty of oil leak right now too....

**thixon** · 01-11-2008, 04:39 PM

My old sIII would cruise at 70 on I-20 with no problem. This was after an engine rebuild, and with a fairey OD.

**Tim Smith** · 01-11-2008, 04:41 PM

Originally posted by Jeff Aronson

A properly maintained engine [oil changes, tappet adjustments, point adjustments and replacements] will last a long time. Highway running has not weakened my engine over hundreds of thousands of miles.

I can attest to Jeff's Comments above about a properly tuned engine giving good life and usability.

My airportable was bought *almost* sight unseen with a turner 2.5 (I think) and a roverdrive that ran like a raped ape. I picked it up in Jacksonville, FL and drove straight back home to CT. On the way back I distinctly remember seeing the speedometer pass 85 mph for a short while as I was passing some big rigs and an irate Jeeper that I had just cut off.

In fact to tell you the truth, the truck had more peddle in her but it sounded like Armageddon so I decided to back off before the main lay shaft ended up in the passenger seat.

The down side is that I think the motor wasn't properly maintained in it's earlier life. There was always a bit of smoke and I was sure there was a rod knock after further inspection. I think the previous owner was doing a lot of stop light racing for whatever reason

.

I've since switched out that motor and it's awaiting a tear down to see what was actually making the knock. She'll still hit 80+ mph with the stock 2.25 I put in there (witnessed by GPS) but only if you keep everything in proper tune.