Thread: a bigger engine in a 101?

thanks all
at this stage it is just in "find out" stage i would love to know
so i can save up my $ 's i dont want to waste anybodies time, but
it must be doable.. any ideas ????

Sorry - just a little confused here

As I understand it we want the 101 to have more omph when towing but also be more more relaxed when cruising at highway speeds.

Ian is investigating the installation of a 4.6 to deal with the oomph issue. It has been suggested to change the transfer gear ratio to make the overall ratios higher and give better cruising.

Changing the ratios on face value would worsen the towing problem even with a 4.6 - but all may not be what it seems. While the 101 with standard gearing cruises at about 90kph, it still has a top speed of 125-130kph so raising the overall gearing may move the torque sweet spot to a higher criuising speed even with a load - so more torqier engine and higher gearing may work well together.

If it were me I would leave the transfer gears alone in the first instance and just get an overdrive. That way you still have the pulling power lower down if required from the standard gearing but have the overdrive for the highway.

Later if required - you can tinker with the transfer case gears if things were still not meeting requirements.

101 Ron (Ron) is the man to speak to about these things as he tows a bit and uses his 101 a fair bit.

Garry

thanks for that it makes great sense
i will give that a go!!! and will give ron a call
re: over drive

Ron has an O/D and RR gears.

I bought a LT95 with an O/D on it for $500 but have not fitted it yet.

Garry

Thanks Gary.

I am just not a fan of Fairey O/D I had one on my 1980 RRc LT95 standard 3.5 carby engine and it lasted only 6 months from brand spanking. Granted it was the early type without the oil feed but still it turned me off them for keeps.

Going back to the RRc transfer ratios in Ron 101s, it would need to be clarified which model ratio he is using, as the first ratio was the same in the RRc and the 101 and they progressively up'ed the ratio until the one mated to the 4BD1.

As I understand it the one that is the closest to the 101 is that out of the Stage 1 V8 and early County V8 (because they ran larger diameter tyres).

If that is the situation, I probably have at least one Stage 1 LT95 that may be of use to Iain (at the correct price of course).

Diana

I have posted another thread in the techical section because I had seen the post on the English 101 and then found this.
Gearing wise I would play with a overdrive with a standard motor or slightly above standard.
You can play with the transfercase gears for triming at a later date of gear ratios to suit your needs.
If running a 4.6 motor I would change the diff ratios 4.7s ? as the 4.6 litre motor will have the torque to pull the higher ratios in the 101.
The 4.6 motor will destroy the overdrive.
The advantage of the overdrive in a 101 is it keeps the gear ratios closer together for the advailable power output.
My 101 ran the 4.7 diffs with the standard motor and it was not a success and it was returned to 5.57 diffs as the gear spread was too wide with the 4.7s with top gear being too tall for the advailable torque and third too low for the slight hills on the highway.
A 4.6 litre motor wouldnt have this problem.
My 101 running 1.112 transfercase gears was still too low geared even for the 3.5 litre motor.
I now run this transfercase ratio and the overdrive is it is perfect.
First gear is only used for moderate off road driving, hill starts and moving trailers from a standing start.
2nd gear is normal starting off gear.
I do not worry about the overdrive around town at all.
I drop the overdrive in on ther highway for a 100kph cruise at some thing like 2800 rpm.
At 90kph....about my best speed for fuel burn the engine is doing 2500 rpm in its maximum torque zone.
I can get up to 110 kph at 3200 rpm in overdrive . but the returns are greatly reduced due to the box shape of the 101 and wind drag.
I can tow one tonne at 100 kph in overdrive on flat road.
If I come to a hill I drop it out of the overdrive , or just let the speed wash off and pick it up going down the other side.

The other thing which has to be taken in account is the front tail shaft.
With 5.57 diffs these things are spinning very hard.
I find the practical limit of speed with this diff ratio is 120 kph as the tailshaft vibs will cause it to destroy itself over a long period of time.
The canvas starts to get a little bit out of control above this speed too.
4.7 diffs will reduce this problem greatly with the tailshafts at higher speeds and I feel the only motor that will pull the 4.7 diffs is the 4.6 litre.
Having said all this I am happy with what I have now.
I get a 100 kph cruise on good road with a moderate load.
Yes Iam a bit slower going up some hills than my mates in there tricked up modern 4wds.............but much faster than any stock bog 1977 vintage Patrol or cruiser of the time.
The other thing to remember is the steering ,handling and brakes are not really up to those higher speeds.
I will be waiting for Garrycol to drive my 101 in four weeks time for his views on my 101.
My long term lines of though on my 101 is to wear out the standard motor( I am happy with it and gearing presently).
I hear all the stories of liners slipping on the bigger bore 3.9 and 4.6 motors .
The 3.5 seems to be much more bullet proof .
My idea is to stroke the 3.5 using the standard block and do it with out removing the motor from the vehicle.
I have heard the stroked 3.5s rev harder than the 4.6 without much porting work.
I need information on what was usually involved and if there was any down falls.
I think the stroked capacity is about 4.2 litres.
The other thing I would do is try and leave the compression on the low side of things if possible even though it means a slight loss of power as the wide ratios and the need to lug with higher gear ratios means the motor will be less likely to ping.

The101 exhaust mamifolds will have to be used and they will kill the breathing of a bigger motor........so the bigger motor will need to be running in its torque zone alot.(to get the best out of it)
MGB V8 manifolds will fit with exhaust system changes......good luck if you can find any.
From what I have learnt on this site over the years the heads can be interchanged between motors , but you dont not use the outer bolts on the later motors when fitting earlier heads.
There are differences on later motors with manifolds and distributor drive gears etc.
It can be all work out at the end of the day.
A motor transplant is a lot of hard work in a 101.
I would check to see if you are getting the best from the 3.5 and your gas conversion.
A bigger gas mixer may give you more punch.(I am guessing you are using a impco ca150 like Garrycol)
I wish my 101 was running when you were in town iain.
I find my gas system which is using plate donuts is working well with only a slight loss of torque when pulling in top gear under a heavy load.
I still need to fix a flat spot above idle in my gas system as I am to lazy to fix it currently by changing to a different type with a more sensitive second stage diaphram.