LPG conversion

[Chris_C]

I was running a standard prop, but I do abuse mine a lot (a lot of high RPM launchs, snap gearchanges etc)

I'm pretty certain the reason mine went was down to weak engine and gearbox mounts. I run a standard 1.7 clutch, but it is/was a brand new Valeo unit. I'm starting to get slip now after 18,000m but I havn't needed to adjust it in the meantime so that should just be cable adjusment. That's not hugely different to what I was doing on a clutch beforehand.

Failure mode of my prop, Vulcanisation held well, as did the splines, it soley tore the rubber inside. Rather than have a custom prop made, I'm hoping to engineer an insert for each end of the ali prop thats replacable. Granted it'll still snap, but I can cope with that every 15,000miles and will just put it in the yearly service.

[Clan]

Yes thats how they can fail , the bonding between alluminium tube and the rubber . This can happen even with th B14 the cause is mis-alignment , the rear engine mounts are adjustable for height and it is important that the propshaft is in alignment with the two splined shafts with no strain on the rubber propshaft bushes/couplings .
The metal splines can strip too but only due to incorrect fitting when only the first 10mm or so of splines are engaged .

[Wilbo8711]

so are the main differences between the 340 and 360, outside of the engine, the prop, bell housing and clutch? are the props interchangable? i haven't yet been under my 340DL as i've only had it a month and it's not stopped snowing! it's my first one but i'm hooked. just need a bit more! if we were to upgrade the prop would the next weakest thing twist? i.e the half shafts. i was thinking (as i said, i haven't looked) a german alternative cut and shut properly.
15,000miles sounds alright though. maybe more if gentle? i mainly do motorway miles.
if you could keep me updated on how the prop engineering goes i'd be grateful :-)
where abouts in wales are you based Clan? i wouldn't mind seeing what can be done with a 300! pm me if you prefer. i travel all the way from taunton, somerset to cardiff and carmarthen on a regular basis and will be moving to cardiff in the new year. there's not much going on round here.

[Clan]

The 360 is completely different, the 240 2 litre engine has its own dedicated 360 bellhousing , coupled to the rear transaxle with a heavy metal torque tube about 4 inches diameter with a one inch diameter shaft going through the middle to the transaxle from the clutch supported with three bearings within the large tube ,
This is one complete assembly, all one rigid piece, the engine , torque tube and rear transaxle , fixed to the chassis at the rear with two bolts and the engine at the front with two bolts so just by releasing four bolts the whole lot will drop out in one piece , with the gearlever neatly attached to the top of the torque tube ...

On another theme i knew someone who coupled a mildly tuned renault 5 turbo engine with about 150 bhp to a 340 CVT .. using a manual clutch so you only used the clutch to start off and press in when you stopped to prevent stalling .. This absolutly flew . anyone who has driven a standard B14 CVT which works properly will tell you they go very well .( about the same as an old vauxhall cavalier 1800 injection in acceleration terms)
The standard propshaft was used if you drive with respect and only apply power when on the move the belts and propsaft were adequate ..
This is probably a better way to go than a 360 beacuse any extra power a 360 engine may have is used to move the heavy engine and torque tube around unless you get some serious power from it and the B14 always handled delightfuly on decent tyres , something a 360 did slightly less well .

[classicswede]

The whole drive line of a 340 and 360 are different.

From what I have seen the bonding tends to only give out on the early props. Later ones tend to shread the splines.

With my 2ltr 340 I had problems with the prop sliding off regardless of how tight the clamps were. After changing the prop for another one it has been ok for quite some time. There is a steel prop available for the 340 with UJ but I have heard there are vibration issues with it. I have not tried one myself but was going to get one a while ago but I think I'm going to do something different.

I'm a LPG person realy but have been thinking about putting the 1.9td out a 440 into the 340. On pump fuel it would be more exensive to run than LPG but other fuels are available for the oil burner that can be quite cheap. Prop wise if you drive like a sissy it should last a while. Long term I would weld flanges onto the bellhousing and gearbox with conventional prop between.

[Clan]

I have a 1980 343 with 250000 miles and still on it's original propshaft , i ran that on a volvo approved Landi-Hartog LPG kit from 1983 to 1990 when LPG became uneconomic , much the same as its heading now .
Has anyone stopped to think why the standard propshaft is as it is? ie alloy and large diameter? Alloy to reduce the rotational inertia which is critical, and large diameter to take the torque .
The inertia of the propshaft has to be low as when you change gear as it is in fact the gearbox input shaft and has to be speeded up and slowed down by the syncromesh cones .. using a standard steel propshaft would completely mess up the gearchanging ! The dutch knew what they were doing :-)

ALL the propshafts i have seen with stripped splines over the years causing breakdown and a tow in were due to the propshaft not being slid on fully after being refitted , and only clamped on about half an inch of spline instead of the full inch . People would slide them the wrong way ie to the front instead of the rear before tighening the clamps to breaking point ! They only need 25 Nm ..

[Chris_C]

Originally Posted by Clan

Yes thats how they can fail , the bonding between alluminium tube and the rubber .

If you look at the picture mine didn't fail on the bonding, it's torn the rubber about 10mm from the edge. I agree it could be locational issues though which is why I'm suspect to the engine and box mounts not being as solid as they used to be.

I was hoping originally that a 340 or 360 halfshaft CV would have the correct splined to fit my bellhousing and gearbox but they don't, that would have provided a nice flange.

However, when I pulled the prop off and started removing the rubber from the ends I noted what Clan has said, it is *very* light. Engine speed-ness of the prop I guess forces this, hence why I'm going down the machining up inserts route to replace the rubber rather than replacing the entire shaft.

The one thing I'm keen to keep is some kind of rubber to give that small moveability. I've a design I think will work, just need to get some made and tested. That will allow the use of the original ali tube and give a removable replaceable rubber bit.

[Clan]

Yes i see , i guess if the shaft is out of alignment the rubber there is constantly worked hard flexing and over time it gives up ..

You could get light alloy end pieces machined up and welded to the propshaft to take rotoflex couplings much like the Alfa 75 which has the same transmission arrangment but with the flywheel and clutch at the rear also, so the inertia mass of the propsaft is not important, it has a steel propshaft .. Alignment of the propshaft would still be crucial on the 340 though ..

[Wilbo8711]

i agree, the standard volvo set up cannot be beaten for reliability but it's mans nature to spoil good things and to love the idea of achieving a personnal goal and to tinker! i just can't resist the idea of owning a car that's as economic as the best modern tat but still have character and most importantly not cost as much as a years wage to buy! we're talking 360 bits, a 300 pound engine and a few weekends work
so would any engine bolt straight in with a little tweaking to both 340 and 360 but to get any reliability from the prop etc i'm better off swapping the kit from the 360? and this is a straight forward swap. anybody got spare 360 bits?? not having much experience with this sort of thing or knowledge of volvo 300's. wouldn't mind having a look around a finished project and to get some insight sometime if anyone's willing? i won't be starting mine til february at the earliest. i'm mad about old cars so to keep me from buying another project car this seems the best option money and space wise!

Will

[Chris_C]

The 360 stuff won't bolt up to the diseasal engine. The reason the 440TD is such a handy choice is the block is the same as the 1.7, therefore it should just be a job of swapping the sump and bellhousing from a 1.7 onto it, then the 340 prop will bolt straight up as well as the engine slotting straight in on existing mounts.

The 360 stuff won't bolt up to the block, so you need lots more custom bits.

If you've not done too much reading, post 26 of this thread ( http://www.volvoforums.org.uk/showth...t=57018&page=3 ) and post 2 of this one ( http://www.volvoforums.org.uk/showthread.php?t=50710 ) should point you in the right direction.

The below pic is a 480T engine with a 340 1.7 sump and bellhousing, and the second thread shows that in the engine bay.