François' RangeRover => Chevrolet Conversion:
Rpm Calculations-Excel Spreadsheet
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Hi
John,
So
you are curious , you’ll get the story .
It
began with the transplant from a 400cid ’91 Vette TPI engine & fuel system
in a 4sp LT95 RR.
During
offroading it appeared that the RR body could not withstand the abuse , so I transferred
everything in a ’96 90 , R380 ,
LT230. The RR was used almost daily on the road and some off road and I drove a
couple of years with it, while the LR is mainly for off road use, but it has to
be possible to drive it daily.
The
whats and why’s:
400
cid , I wanted torque and I got it , plenty.
’91
Vette ,fuel injected ,(means always easy starting , no problems with carb float levels
during off roading ),water proof ECM , low profile engine (low intake manifold
& shallow oilpan), suited steel exhaust manifolds which are easy to modify.
The
parts:
Adapter plate
available in the UK or Australia , no problem. I made one myself because I wanted a more or less watertight connection and that was better done with a ACDelco gear reduction starter which has no nose .So you only need a hole for the gear to get through instead of a big hole for the alu nose . The small hole is easy to seal. The adapterplates I saw were for normal starters , so that’s why.
Clutch,
flywheel , 153 teeth , 10,4 “ clutch . That’s all you can stuff in
the LR or RR. That is what you have to live with if you use the original
bellhousing and gearbox . In the 4 sp I used a Centerforce dual friction set
from a Chevy . Gave me no problems , only once when I parked the car in deep
sand . When I wanted to drive away I thought it was already in low gear . It was
not and the clutch smoked away.
Throw out bearing and slave cylinder are original , you need only a longer pilot
bushing. The input shat is shifted the thickness of the adapterplate back from
the crankshaft. The R380 has a
different input spline count , so the Centerforce set could not be used , nor
could they supply a fitting set .Pitty. I had a custom plate
made and used the Centerforce clutch cover . Version 5 of the plate holds . It’s solid in every form , no springs and the
friction material is glued and riveted to a solid disc. I didn’t want a
complete racing clutch which is just more or less an on/off switch , but want
some slippage possible for off roading. What happened to a standard 4,2 RR plate
happened before I could shift to 5 , you can see on the pic. The gear shifting
feel is different now , but you need to shift not that much anyhow , lots off
torque.
Mounts,
corvette rubber motor mounts , they are fitted to the engine instead to
the frame as almost the rest of the Chevy’s. It means the mounts on the frame
are quite easy to make , see the picture. Even the locations on the frame are
correct when it used to be a V8 . See the pictures. I prefer Chevy mounts on
every engine swap because the rubber part is fully enclosed by steel. What means
that when the rubber wears or breaks the engine will still be aproximately on
its original location , nor can the engine slide forwards when descending a
hill. Coolers are expensive and not at hand at the trial.
Serpentine ,
the whole system from a +/- ’91 Caprice , without fan. It’s compact
.I deleted the original steering pump and switched the air/smog pump for a
steering pump from a L6 Cherokee. It needs an extern reservoir like the RR and
LR. I took a system with airco which I have the idea to convert to an onboard
air system for almost 7 years now.
Cooling,
just the biggest radiator you can get, in my case one from a 4.2
in my RR. In the LR I use a standard 2.5 diesel , both gave me no
problems . To lower the high under hood temps I had in the LR , I drilled on
each side of the hood 3 3” holes.
Works great .The wind is generated by 2 aftermarket fans . If you want the size , I “ll send you it later , I don’t have it at hand
now. The overflow tank is original on both the LR & RR.
Air cleaner,
because of the TPI , original ducting . On the RR a filter from the same
Caprice on the inner fender , lots of room. In the LR I started with a throttle
body filter from K&N , which didn’t do what I expected (after the 2000
Belgium National [ www.belgium-national.com
] I found lots of sand in my engine on both sides from the pistons , needed a
new engine) and made a giant 2 stage air
cleaner with ’96 Camaro and self made ducting.
Fuel,
on the RR I used a in-tank pump, original Vette . On the LR an extern
aftermarket pump and an AcDelco inline filter . The fuel consumption on the RR
(400 cid) was +/- 6,5 km on every liter on the highway , 4,5 city . The LR is a
different story . The engine has to push a shed with an amazing Cw through the
air , bigger tyres, the engine is a 383 now and the ECM program is not fine
tuned jet. But the consumption will be higher now ,+/- 5,5 on the highway. But
what the heck , nowadays the LR is for off-road mainly. And a LPG system is
still in my mind . Fuel prices are different here in Europe.
Exhaust,
modified Vette manifolds , will make a picture of it and e-mail and
describe it to you later. In the LR
I switched to block huggers because of their bigger diameter. I just feld that
the engine needed more exhaust. The front Y pipe
is to be see on the picture .The Y pipe is followed by a cat and a 3”
turbo muffler .The system is custom made except the last part , which is from a
V8 Discovery.
Transmission, manual
,standard .I prefer an automatic , but I don’t like the
Torqueflite and don’t trust a ZF in combination with a lot of torque
and off road. A conversion to a GM overdrive trans is a project for the future. The R380 has provisions for a cooler , but temp tests showed
no need for that. The LT 95 gave me problems on the intermediate shaft end
bearings from the t-case. I changed them every 20.000 km and enlarged the sump
by making a hump on the cover. The LT 230 has no problems , temp readings and
sump are normal.
Propshafts,
standard , I just lubricate them regulary and I avoid water crossings .
But on off roading trips I carry a grease gun.
Axles,
they gave the problems , mainly caused by my own fault.
On the RR , the standard 9 spline were used , the system with halfshaft
– CV joint - stubshaft. One halfshaft on the rear and one on the front broke
once .The front diff exploded , much to much wheel spin on one side , own stupid
fault. With a 3,5/ 4,2 Rover I expected it to be the same story. But it is a
strange sight a hole in your front diff cover. An ARB replaced the original diff
, just took it apart and still looks perfect.
On the LR the front halfshafts are Suzuki size on the CV joint side ,
so….I replaced the LR axle for the RR front axle. In the south of France my
mate (Jeep CJ-7, Chevy V8 ) and I tried some rockcrawling which cost me one
halfshaft left front inner. Until
the Belgium 2001 event no trouble. Here I broke the rf stub and a rr half and
had to be pulled out of a mud hole .Also because of taking the wrong track . The
9 spline are just not forgiving on the LR with the 34” X 11” Mickey Thompson
muds. Time for changes. Because having a little bit of time now, the axles are
now being built to 24 spline HD shafts, HD CV joints, ARB frt & rr and cross
drilled discs and Kevlar pads.
Body,
The large HEI ignition would hit the firewall , so I used the smaller
Camaro version. With the engine fitted to the car it would be impossible to
remove the distributor , so I modified the upper part of the firewall. This is
not necessary , you can lower the engine by removing the motor mounts, I just
did it to make it possible to change the HEI during off-road.
Springs,
OME +/- 2” lift in catalog
, to compensate for the added weight from the engine . In my case 80 kg. Aluminum
heads , brackets & manifold, tubular steel headers, lightweight nodular
12 ¾ flywheel
, but with steel AC pump.
So , this is more or less what I did , it may not be complete . When you want to know more technical details I’ll will read from you.
The most important thing about the conversion is what do you want from your car and engine .From the RR I wanted a daily driven offroader while the LR has to be an offroader which has to be fun to drive daily (if wanted) and bring me to the mud or event with a normal driving speed instead of driving at a low speed because the tires can handle the speed , the center of gravity is too high etc.
So the engine choice is important , you want a ram air engine , while my
engine is tuned for lots of torque at low revs. With the ratio’s from the
t-case you can tune your cruising revs and top speed . That's why I started with
a 400 ,low revs , good cruising at 120 km/hr in the RR. For the LR the engine
became a 383 (I ran out of 400 4
bolt castings) which has has his optimum at higher revs and revs more easy .Even
when the rest of the engine is the same as I used for the 400.That’s why the
LR is in combination with the
overall gearing much faster than the RR. The R380 is from a RR , which has a
longer 5th gear than the LR version , the t-case is 1,22 instead the 1,4 from
the standard LR .So when the cruising is at a lower speed you can take the 1,4
or even the 1,6 ratio t-case , and so on. My intention was to cruise at 130
km/hr at as low revs as possible but the 383 keeps pulling with ease. When I’m
in a hurry (and the police sleeps) I cruise at 160. And still it brakes and
steers , amazing. In fact is a combination which starts at the air cleaner and
goes on to the tires. You can calculate your cruising and top speed rpm in the .xls
attached
The same for the location of the engine, When you don’t need the full
articulation from your front axle , you can place the engine crankshaft at its
original position . That’s the best , it keeps the t-case in its original
position , what means the driveshaft angles don’t change and keeps the
U-joints alive longer. In my case I want as much clearance under the axle as
possible , so I placed it as high as possible , what means an engine as low
profile as possible. Low intake and low sump . A high engine is than only
possible with a hole in the hood. A low sump creates trouble with oil starvation
when driving under for LR normal but for Vette fatal angles. So a standard sump
is the easiest way to go and will not create any problems , I just didn't want
the sump to be lower than the bellhousing.
You see , it’s a long story with a lot of discussion possible .Also with a lot of ways to spend your money on things what one finds essential and the other a total waste of money and/or time. I can only tell you what I have done and why. You know what you want and what you want to spend on time and money.