MQ V8, use of diesel 5 speed?

[JelmerMQ]

I have a 84 MQ with a L28 and 4 speed. I'm going to order a V8 swap kit from Castlemain but I want to use a 5 speed from a diesel.

I was thinking of just putting the 5 speed on the stock location of the 4 speed because the V8 will be clear the firewall better and since its a short engine there will be enough space between the radiator and fan.

Am I thinking wrong or will this work?

[V8Patrol]

The L28 & 4 speed box will give a good firewall clearance for the V8 without any need for adjustment.

A SD33 and either 4 or 5 speed box will pull a V8 back hard onto the firewall and WILL require a massaging of the fire wall and it will still be a tight fit.

fitting a 5 speed to the std mounts where a 4 speed and L28 was, WILL push the motor foward 135mm.

Best bet:
fit the V8 to the 4 speed box as a single conversion.

THEN.....

convert it to the 5 speed.
( this means relocating the g/box mounts, altering tail shaft lenghts, & gear lever / hi.low lever mods aswell )



TIP:
it will be far easier if you have the 5speed and the V8 prior to the conversion "on the w/shop floor".... you'll need a custom made spigot bush to pickup the differing input shaft lengths between the 4spd and 5 spd boxes..... or you'll need to swap over the input shafts.


TIP 2:
Watch out for the 4spd input shaft hitting the back of the V8 crank when its all bolted togther, in some cases the clutch will disengage but due to the input shaft riding hard on the crank it wont change gears easily.
This is only related to SOME V8's.




Kingy

[JelmerMQ]

My Patrol is going apart completly. Body is rusted out and I want to have my frame galvenized so relocating the supports is no proble before that.

Is changing the input shafts difficult?

So You recomend to order the conversion kit for the L28-4 speed Patrol?

[V8Patrol]

My Patrol is going apart completly. Body is rusted out and I want to have my frame galvenized so relocating the supports is no proble before that.

Lots of expence for little gain !

Is changing the input shafts difficult?

fairly simple job...... personaly I perfer to make the custom spigot bush and not upset gear meshing via a front shaft exchange, if you know someone with a lathe, it only takes about 10mins to knock up a spigot bush !

So You recomend to order the conversion kit for the L28-4 speed Patrol?

yep
hint: get it drilled for both the HOLDEN & CHEV patterns, this way you'll have a huge variety of engines that will fit in there from a red 253 to the latest chevy ! There's plenty of meat on the Castlemaine RodShop bellhousing for the multiple drillings, I've even seen on drilled for chev / holden / & nissan RB30 !

Kingy

[JelmerMQ]

Thanks for the answers! But I ran into another problem! My Patrol is a swb and has a spoa so if I place the gearbox more backwards the angle of my rear driveshaft is pretty big wich causes vibrations I think.
Also my front drive shaft will hit the crossmember.

What if I choose to go for the first option (diesel 5 speed tranny on 4 speed tranny frame location), will the V8 be to close to the radiator?

[V8Patrol]

I ran into another problem! My Patrol is a swb and has a spoa so if I place the gearbox more backwards the angle of my rear driveshaft is pretty big wich causes vibrations I think.
Also my front drive shaft will hit the crossmember.

your 100% correct !
So ... you cut the x member out and shift it back its own width ( about 150mm ) & you shorten the rear shaft and lengthen the front shaft.
If your overly concerned about uni angles.... search "broken back uni angles" or rotate the diff snout up to lessen the angle somewhat !

What if I choose to go for the first option (diesel 5 speed tranny on 4 speed tranny frame location), will the V8 be to close to the radiator?

......
Measure the length of you chosen V8 from where the bellhousing bolts up to the front edge of the fan blades..... add 135mm to that measurement.

Now run the tape measure from the back of the L28 where the bellhousing bolts up & re- measure using the measurement you got from the V8 + the 135mm.....

That will tell you exactly where the front of the V8 will sit in relation to the radiator !

Obviously you can shorten the V8 by dropping of the engine fan, the smallest gain here is about 90mm.



You also run into other issues by just fitting the 5spd where the 4spd was.......
Your gear levers will be 135mm further foward which means cuting and re-welding tunnel floor to suit the new position, bending gear levers so they clear the heater section, carpet of floor mat mods....
NB:.... if you dont convert the top cover on the 5spd box, the gear lever will be the 135mm further foward ... PLUS another 125mm so about 260mm further foward than where the current 4spd gear lever comes through the floor

That puts the gear lever coming up through the floor where your heater box ONCE WAS !!!




Been here done all the B/S work only to find it FAILED !




Fit the V8 to the 5spd on the w/shop floor.

then

fit the V8 to the 4spd in the engine bay

then

drop the 4spd out

then

convert the top covers over

then

remove & replace the x member

then

fit the 5spd to the V8 in the car

then move or make some new g/box mounts to suit.





the above IS the simplest conversion by far


and its what I've done to SEVERAL swb MQ's and a few of em were SOA's



Kingy

[JelmerMQ]

Your right, Kingy! I already had that gear lever problem once!

Ill order the L28 4speed kit!

A friend of mine rebuilds gearboxes of Japanese cars so he can change out the input shafts of the 4 and 5 speed. Also, my drive shafts are made longer but it doenst look to strong so Ill have a specialized company do that.

One more question, The cluch! I bought a Chevy 5.0, what clutch, trowout bearing and flywheel do I use? Nissan or Chevy?

[V8Patrol]

The cluch! I bought a Chevy 5.0, what clutch, trowout bearing and flywheel do I use? Nissan or Chevy?

Using the 5spd box without doing the inputshaft conversion:
Nissan clutch fork
VB = VH comodore thrust bearing carrier (ex M20 M21 G/box)
Nissan MQ thrust bearing
V8 chev or V8 holden flywheel drilled to suit the chev crank
1991 or 92 TDI nissan clutch plate
V8 chev or V8 holden pressure plate ( I use the V8 holden 11" pressure plate with this combo )
&
1 Custom spigot bush.





Using the 5spd box and doing the inputshaft conversion:
Nissan clutch fork
VB = VH comodore thrust bearing carrier
Nissan MQ thrust bearing
V8 chev or V8 holden flywheel drilled to suit the chev crank
Nissan pressure plate ( 10" pressure plate is the biggest you'll get, also need to get the flywheel drilled and stds fitted to suit... see RodShop for this )

As for a clutch plate..... your limited to a 9" or 10" plate, you'll need to take the front shaft into a clutch specialist and search through his stock / lists for a suitable plate.......
This is the main reason I perfer NOT to do the input shaft conversion, it limits you dramatically to clutch plate sizes..... the custom spigot bush is the cheapest option in the longrun !

You'll have a V8 with loads of grunt ... a 9" or 10" clutch doesnt lock up as well as the 11" setup. ESPECIALLY when you do a river xing or play in water.

been there tried that....... and replaced the clutches as a result !


just for comparision .......
The std L28 plate WONT HOLD a 253 V8 after a short swim

[V8Patrol]

Additional info:

The big differance in the input shafts, apart from the length, is......


THE SPLINES

The diesel ( 5spd) has a fine spline and therefore more splines

The Petrol ( 4spd ) has a much coarser spline and therefore less splines.


The clutch plate you decide on will need to have the right diameter hole and SPLINE count to match up to your chosen input shaft.

The availibility of differing plates is very limited for the 4spd shaft....

The plates for the 5spd shaft however range from an 8" plate through to an 11" plate.


again a search through your local clutch specialists stock lists books etc will reveal this.


Kingy

[JelmerMQ]

The stock 5 speed input shaft it is!
You mentioned a Nissan TDI clutch plate, do you mean a Patrol 4.2 TD?

[V8Patrol]

The stock 5 speed input shaft it is!
You mentioned a Nissan TDI clutch plate, do you mean a Patrol 4.2 TD?

yep

There's 2 plates for that model... one will line up perfectly with the V8 holden pressure plate, the other will be 10mm to big !
( the V8 holden pressure plate is called the "tow pak" )

You can use the bigger plate if you also use the Nissan pressure plate that goes with that plate, this requires re-drilling and fitting studs to the flywheel tho..... not a major job




For both clutch setups:

there is a small moulded 'bump' in the inner lip of the belhousing that will need to be ground off so the pressure plate clears..... 2 min job with a 4" grinder


again ....
like I've said allready...
PRE FIT IT ALL ON THE W/SHOP FLOOR !

saves SO much time and agrivation

[JelmerMQ]

Yes, I will set it all up on the floor and after everything works Ill put it on the frame. The new body will go on there after that.

[neRok]

i am keen as to v8 my patrol. its originally a diesel 4 speed swb and has been half converted to 5 speed (plates were used to join the new gearbox mount location to the old chassis mounts). i have pulled the motor and the 5speed has a longer shaft than the spare diesel 4 speed i have, so i presume 5speed would be 195 shaft (based on 3 choices on CRS webiste of 184, 195 and 210). i also dont have any driveshafts atm, so moving stuff backwards/forwards is possible.

i want to drop in a 304, not sure how I should proceed as most of the comments above I think relate to using diesel 5speed in 4 speed L28 chassis (which have different gearbox mount locations...?) I have checked out CRS website and they do an adapter plate to stock diesel bellhousing, or a new bellhousing to suit L28 gearboxes (but with bellhousing changed, the only difference to diesel is input shaft and sticks...?).
So I think the comments above suggest the bellhousing and a modified spigot to suit the shorter diesel shaft (and you stick with the diesel shaft as it allow greater clutch choices). But I am not sure how this will effect motor location, if I fit motor to ‘stock’ gearbox location (I mean bellhousing in relation to firewall), the motor will hit the firewall. If I move gearbox forward for motor clearance, the gearsticks will be in a bad position (especially if moving the ~135mm of 4-5 speed difference)
The adapter however says it allows larger flywheel to be used than the bellhousing, and it comes with a spigot. So would this be better to go for in my application, as I presume the extra thickness of the adapter will push the motor forward sufficient to clear the firewall? This would then leave the gearsticks in the normal location, so ultimately I wouldn’t have to do anything.

I have also just sent an email to dellows, so will see what there bellhousing offers.

Any advise would be appreciated.

[V8Patrol]

Ok .... I've read your post half a doxen time trying to figure out what you have....


Put the 5spd on a floorjack

unbolt the extended gearbox plates and sell em

bolt the 5spd back up to the STD g/box mounts &...
swap the top covers over to get the shifter into the right place
(in your case fit the 4spd top cover to the 5spd box )

Order a bellhousing to suit the L28 and fit it to the g/box

Sling in the V8 with the extended spigot bush




The SD33 is a long motor and to accomindate it they ( nissan) pushed the g/box back..... hence the central position on the g/box so that the shifter comes up through the floor in the std floorpan hole
The L28 is a shorter motor in comparision so they (nissan) moved the box foward, hence the rear location on the g/box so that the shifter comes up through the floor in the std hole position


When yours was converted to the 5spd, they couldnt shift the motor (SD33) so they extended the box mounts .... remember the 135mm extension housing that holds the actual 5th gear sits between the box and the transfer... the g/box mounts are therefore moved further back... IE: like your extensions.

If you use the SD33 addaptor plate then the V8 you choose WILL rub up against the firewall.... very hard ... = a firewall massage + the heater box also needs an "adjustment" further into the cab.....
Ugly opperation !


By shifting your 5spd onto the std mounts you'll get the V8 to fit easilly with good clearance on the firewall and NO massaging required

[N2O]

5th gear extension cover is 100mm, not 135.

[neRok]

thanks for the info V8Patrol, what you have said was what i was hoping to be the case.

[Chook350]

I run a 327 with a marks kit, l28 4speed, i may only get 5k to a litre of gas but its fun, heaps of clearance to the firewall, after the pbr clutch failed i had the clutch man we used to do me something up. I ended up with a vl turbo pressure plate internals in a chev cover and 300zx clutch plate, cost me a pretty penny but has been abused alot and is still goin strong.


Zeds clutch and brake, they used to be port melbourne clutch and brake, think they are still in sunshine vic