Sunday, April 22, 2012
Standard VA TPBG engine
Horse Power 11.98HP
Power 54 bhp
Police Specification VA TPDG engine
Horse Power 13.22HP
Power 67.7 bhp (est)
You need either WA Pistons or the MGA 1600cc "Flat-Top" Pistons for the increased 1708cc cylinder bore. The MGA Pistons are usually easier to find, but will need the gudgeon pin hole reaming out slightly to take the original connecting-rod little-end pins. (This hole must be reamed to be a sliding fit).
SVW Parts also stocks a slightly larger Wolseley Engine head gasket which is more suitable for the larger 1708cc bore.
Is it 1708cc or 1709cc?
My maths says pi*bore/2*stroke*4/1000 = litres and I get 1707.638cc or 1708cc when rounded.
Wow, this post resulted in some really good information from the SVW egroup on Yahoo as well as the SVW Register, thanks for all the feedback. I summarise below:
Robin Page - Australia
I asked my engine man to do this to my VA1880S. He carried out an ultrasound and did not consider there was enough meat in the block. So he bored to 72mm. Pistons and conrods were made to order to achieve a compression ratio of 8.55:1. Capacity is now 1657cc. Standard MGB camshaft grind. Engine was balanced. It is a very strong and torquey engine and feels more like a 6 than a 4.
For what it is worth.
Bas de Voogd - Holland
I think there is quite a difference in casting thicknes’s possible. Personally I am not in favour of this operation. Remember MG’s only experimented with it. There is no proof of larger VA engines other then 5 experimental ones and the typed Policecar Sales leaflet. Quite well possible that even these five TPDG experimentals were a thicker casting too. There are however a number of succesfull enlarged bores running around without hassle so far.
The attached photos (courtesy John Bannister) show a blown up engine but this might have been caused by a loosened up small end pinch bolt and neglecting the rattle. I know more then one VA loosing their engine this way.[Contact me re photos]
A thought might be to grossly overbore, then press in a thick, engineered sleeve designed to seat on a machined ledge at the bottom.Then bore to specs.Core shift was a real problem on most early engines, world wide. It made thin wall, light engine blocks something for the future.
Saturday, April 21, 2012
Wednesday, April 18, 2012
Restoration attitude: Keep the driving experience as original as possible but make 0864S more suitable for distance cruising in modern traffic and cope with the New Zealand North Island hills. [Updated 14 May 2012].
Probably bore out to Police spec as we will do a lot of hill work and m’way cruising (See another post in this site re engine specification)
New modern head gasket
Main Bearings - leave unless need to replace with shells
Big ends-perhaps use shells-need to strip motor and assess whether to continue to use white metal
Balance components eg crank, pistons/rods etc
Water pump bearing conversion as per Gordon Vogtherr
Triple value springs - convert to double
I have purchased a new "modern" VA camshaft and bearings from SVW Parts
Oil filter - perhaps....however one can see this when you open the bonnet, so may just change the oil more often and use the original filter system (SVW Review 20, 2011 pg 15)
Diode protection on fuel pump to increase reliability from burnt points
Maybe reverse polarity and convert front side lights to LED blinkers/side lights (need to reverse polarity to use LEDs)
Chrome headlight reflectors – lasts longer I am told than silver
Maybe electronic distributor/points conversion……(when I have nothing more to fiddle with!) Horns/Spotlight - keep original two horns etc
Leave original as possible – that is the VA experience
Replace needle bearing with modern as per Vogtherr conversion
Change ratio to longer gearing – to keep revs down for cruising at m’way speed – should be great with 1706cc engine. Here are the details…. the high ratio is 10/47 ie 4.7 as against the standard ratio of 9/47 ie 5. 22, that's about 11% higher and “is very noticeable on the road”. (Quote from SVW Spares).
Automatic brake shoe adjusters are now fitted (adjuster conversion from MG A via SVW Spares)
Master/slaves - line with chrome inserts
Brake shoes – still researching – apparently use softer material
Assess all the components and renew as required - also balance them! as well as the usual advice in SVW Reviews etc on hubs/splines etc.
Replace the 5.00 tyres with 5.50 is recommended by some owners and apparently works well with the 5.00 rims.
Still open to advice/suggesions. SVW Spares have a telescopic conversion and have sold about 70 of these to SVW customers who say the ride is a lot better. Does this still fit my "Restoration Attitude" though? One VA owner is enthusiastic about originals in the front (where they can be seen) and telescopic in the rear (hidden). A topic of rich discussion I expect. Bas' web site http://www.basdevoogd.nl/shock_absorbers.htm has information on this issue (and a lot more!). 0864S had telescopic shocks fitted when purchased so I have the conversion hardware but may try and overhaul the originals and go from there, then I have a basis for comparison.
I will keep on working on this one. I believe two options are favoured, widening the rims to 19x5.50" to enable wider tyres to be fitted...or leave at 19x5.00" rims and use 5.25 (?) tyres. I may have this slightly wrong and will update as I receive clarification.
Seal up overflow as this is dangerous when filling and replace with an elbow and breather flexible tube higher up to a chassis member. Line/seal with modern tank sealant. See SVW Review article.
Tickfords could have any colour as it was a non Morris Factory supplied body. I am pretty certain I will go for the Duo Green combination.
Document all the car history
Get the words down for future owners
Use modern web technology but protect current owners privacy
I use this blogspot site…get some great history down. The blogspot site is soooo easy to set up, no web knowledge is required. I am happy to help if required.
I would be intersted in any opinions, thoughts, suggestions on this specification. I will keep adding to this specification area so all the changes and thoughts are in one place.