design - Land Rover section


2010 updates on the Green Rover
Fine tuning and delayed maintenance

At the dawn of 2010 I decided that it was time to take care of delayed maintenance and to do some fine tuning of The Green Rover's drive train. It has been 11 years since the truck's conversion to a V8, power steering and Borg Warner T-18 gearbox. I've never been really happy with my gear choices or the T-18's loose shift pattern.  My transfercase leaked badly and was wanting to pot out of high range on steep descents.  My clutch was releasing when the pedal was about an inch off the floor and I needed to take it down to the floor to insure the gears didn't grind between gears. And my steering was becoming loose.  I could see free play in the upper U joint between the upper and lower steering columns.  I looked at the kinds of work that needed doing and decided to farm most of it out to Specialists.  I usually do all or most of my work myself except when specialized knowledge or an experienced hand at something is required.  And most of this project needed to be farmed out if it was to be done right.

Starting with the engine:
A couple years back I converted the truck's Ford 302 (5L) V8 to electronic fuel injection.  But I didn't complete the job.  I rewired the truck, replumbed the fuel system including mods to the rear fuel tank, installed the EFI and got it to work but I could not afford to address valve timing.  The carbureted cam timing is different from the Mustang 5.0 HO valve timing.  The EFI system is a sequential  injection system that puts a squirt of fuel into into a port just as the intake valve for that cylinder is starting to open.  With the old cam the fuel arrives at the wrong time, but since the pistons and valves move quickly it isn't too much of a problem.  The engine runs smoothly  once off idle under all conditions.  The down side is that fuel economy is about the same as it was with the carb and the cold idle was a tad rough.

Also, combustion chamber technology has advanced a great deal since 1968.  New designs provide more power using less fuel.   The overall goals were to first get the timing right for the EFI, to increase fuel efficiency and to focus on bottom end HP and torque. Petrol engines tend not to have a whole lot of power at low RPMs.  Normal speed equipment get their high power ratings by robbing the bottom end to give additional power to the higher RPM range.  Which of course does no good to a 4X4 truck that lives in the low RPM range.  So I researched the offerings from a number of companies for a combinations of cylinder head and cam that would maximize low end power while minimizing fuel consumption.  Once I identified and secured the best cam and cylinder heads I could find I enlisted the professional help of a local shop that specialized in Ford small block enhancements.  I knew that fitting a new flat tappet cam design in an old block with new cylinder heads designed to go with a roller cam was not going to be straight forward.  I later discovered that there were valve  spring pressure issues between the maximum rated valve pressure called by the cam manufacturer and what was supplied on the cylinder head.  I likely would have missed that one.  Also the head bolt selection needed to be different for placing new style heads on an early 302 block.  This was a job for people who do this kind of thing all the time and were aware of the compatibility gotchas found in mixing early 302 and late 5.0 components.

For a cam I choose a COMP brand cam that had the valve timing I needed and was designed specifically to provide low end power (power band is 600 to 4800 RPM) and provide the best fuel mileage.  My truck operates at or below 2500 RPM at least 90% or the time. 

After looking at a lot of cylinder head power test curves to see how they compared below 3000 RPM I choose to go with a set of Airflow Research aluminum heads.  Many of the aftermarket performance cylinder heads did not flow as well as stock factory heads below 3000 RPM. I chose the 165 Airflow Research heads because they flow a lot better throughout the entire RPM range than the stock iron Ford heads and had the best specs below 3000 RPM of any other aftermarket performance cylinder head I could find. 

When the dust cleared the engine got new aluminum cylinder heads, new harmonic balancer, new cam, new timing chain, timing chain tensioner, gears, lifters, push rods, rocker arms, timing chain cover (the old one had a corroded coolant passage that had nearly eaten through the wall) and fuel rail that picked up the fuel line at the back of the engine instead of the front.  This corrected the stock Mustang routing where the fuel lines went twice the entire length of the right exhaust manifold.

The only thing left for me to do is deal with the leaking radiator and replace the spark plug wires & fan belts. All well within my skills. I purchased a new aluminum cross flow radiator, a sacrificial anode and redesigned the upper radiator mount so it would be less rigid. I have not measured fuel consumption but I know I am going significantly farther between fuel refills.  The engine runs smoother at low RPMs and has more low end pep.  I feel the results are well worth the effort.

With the engine working well, it was time to address the rest of the drive train and steering. Timm Cooper converted my truck to power steering 11 years ago.  A used lower steering column was sourced from a wrecking yard.  Over the last 11 years the shaft's U-joints were getting  loose.  I opted for replacing the entire steering column to get everything as tight as possible.

The Borg Warner T-18 gearbox came with a granny first gear that gave me a low range first ratio of 70:1 at the axle. I discovered that this was too low to be really usable for almost all the off road driving I do. Second gear low range was 34:1 at the axle which is too high for most of the off road driving I do. On the highway the T-18 is driven as a 3 speed with the vehicle starting out in second gear.  For some time I have been wanting to replace the T-18 with a gearbox that better matched  my truck and the places I drive.  I knew that this would take some fabrication skills that were beyond my abilities so I turned to the best person for the job that I know,  Timm Cooper.

Timm is well known and highly regarded in the Land Rover circles. While my truck was in Timm's shop there as a 109 from France that the owner had shipped to the States so that Timm could do a drive train upgrade on it.  For those of you who do not know Timm, he is the best Land Rover fabricator I know.  He has a keen sense of observation when it comes to vehicle innovations, synthesizing those ideas together into new innovative solutions. He constantly innovates solutions to make something stronger and more reliable, tests it, and improves upon it to make his work as strong and reliable as possible.  He is my first choice for fabrication. Timm is also good at rebuilding stock Land Rovers including drive trains and he is one of the few mechanics in the US who is experienced with the Land Rover six cylinder engine.  This is not a paid advertisement, I'm just that impressed by his work.

Anyway, I had done my home work figuring out which ratios best fitted my truck and the places I take it.  It turns out I want a low range first somewhere between 55:1 and 50:1 (stock LR is 40.7:1) and I wanted a second gear low range ratio that was close to the stock Series low range second gear ratio.  Low range second is a common off road convoy gear for Series trucks and having a similar ratio would make group convoying easier.  My closest match in a strong truck top loader 4 speed gearbox is the Chevy version of the NP-435. Which presents problems since I have a Ford engine and bellhousing. An advantage to the NP-435 is that Timm Cooper had made up adapters to adapt a 2WD NP-435 case to a Series transfercase and I could lay my hands on a used adapter. The problem is that the Chevy version of the NP435 was not going to fit behind my Ford bellhousing

Matthew Jackson of Advanced Adapters helped me solve my gearbox problem.  He informed me that the gear sets that use a roller bearing on the input shaft can interchange between Chevy NP-435 cases and Ford NP-435 cases. The ideal would have been a Ford close ratio NP-435 but it seems they only come with a granny first.  I bought a close ratio Chevy NP-435 and hired a transmission rebuilding company to rebuild the gears in a Ford 2WD NP-435 case. The 2WD version works with Timm's adapter. The gearbox also got a slightly modified tail shaft from a Ford F6000 gearbox so it would fit Timm's adapter.  I would be remiss if I didn't mention that Advance Adapters now offers adapters that allows Series transfercases to be used with the truck gearboxes commonly used on 4X4 trucks. Contact Matthew at Advance Adapters to learn more about these adapters.











close ratio





suffix C on





What this translates to off road is that my low range first is now 50:1 instead of 70:1 (stock suffix C & later Series low first is 40:1) and my low range second ratio is very close to stock Series low range second making it easier to convoy at the same speed on the trail.

When the gearbox was ready I made my appointment with Timm and showed up in my truck with the rebuilt gearbox in the back.  The steering column replacement went quickly with no major gotchas.  Timm replaced the upper & lower steering columns, adjusted the Scout II power steering box and checked the tie rod ends for me.

For the gearbox, I contracted for the gearbox swap which would include moving the transfercase cross member to the rear about an inch, a new clutch and to reseal the transfercase.  Well things are always just a tad worse than you think they are and this was no exception. When he went to remove the gearbox it got stuck and would not come out.  An examination showed that it was full of dried stream bed mud that needed to be picked out.  Also the throw out bearing mounting arms were rusted to the fork.  When he got the box out he discovered that the clutch disk had the perfect amount of wear.  The maximum amount of wear without scoring the flywheel.  I guess I let the clutch go for as long as I could. When Timm separated the transfercase from the gearbox he discovered that the used transfercase I installed used nearly 30 years ago was completely worn out requiring a lot more than replacement seals.  So Timm completely rebuilt it for me as well as sealed it. It ran a LOT quieter now and no longer leaks.

Since the flywheel was a Ford product and the gearbox input shaft was Chevy I needed a hybrid clutch.  The disk is Chevy and the pressure plate is Ford as is the throw out bearing.

Timm looked at the aftermarket front and rear prop shafts I installed about 2 years ago and showed me where both were twisted.  I never have twisted a stock Land Rover propshaft, but the aftermarket shaft tubing evidently were not up to my truck and the way I drive it.  As it turns out the rear flange to flange length on my truck with the new gearbox is the same as a stock Six cylinder 109 so I ended up with a stock Six cylinder 109 rear propshaft. For the front one Timm took the high angle U joints and the long slip joint from the after market front shaft and mated them to a Range Rover Classic front shaft.  This provided a strong narrow diameter front propshaft with better clearance where it passes under the bellhousing.

While Timm was working on my rear propshaft he noticed that the pinion shaft on my rear Salisbury had a lot of side to side wobble so I authorized him to put a new bearing kit into the Salisbury.  I had managed to wear out my drive train about as much as I could without a catastrophic failure.  I'm not sure if it would have held together for one more long camping trip.

While Timm was removing my gearbox he noticed that the frame engine mounts that I had welded on as part of a conversion to stronger engine mounts were not welded properly and were starting to detach.  He also noticed that welds on the bulkhead cross member were separating, More problems that I had missed.  He welded them up for me and added strengthening gussets where the cross member meets the long frame for additional strength and rigidity.

After everything was back together, checked and test driven and I was called to pick my tuck up, Timm decided to adjust the master clutch push rod on the clutch pedal tower to make sure I got all the clutch travel possible.  When he opened the tower enough to adjust the nuts he noticed that the cross piece on the tower that the master cylinder push rod is attached to was very loose in its hole.  A closer look reveled that the cross piece had elongated the hole to the point where it was within a quarter inch of going completely through the pedal. The top couple inches of clutch pedal movement was just movement of the cross piece in its hole.  So when I arrived to pick up my truck Timm was in the middle of replacing my clutch tower with a good condition used one he had on hand.  This is the kind of extra care, attention to detail and effort that I prize so highly in anyone I pay to do work for me.

My planned 2010 upgrade & maintenance project is still not completed, but at least so far the engine, cooling & rest of the drive train work is done.



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