| T O P I C R E V I E W |
| setchrapier |
Posted - 23 Mar 2010 : 19:20:12
Hi
I have just bought a Mk111a and wondered about fitting a complete 1725 Holbay unit (with Webers and 4 branch exhaust).
Is this possible ?
If so would it be adviseable to change the gbox and overdrive aswell ? (The car has o/d gbox already, not sure about ratio's).
Cheers
Nick
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| 13 L A T E S T R E P L I E S (Newest First) |
| janmarine3 |
Posted - 21 Apr 2010 : 06:08:20
Thanks guys. I am going to see what happens and how it runs first , then tinker if nescessary ( I like to tinker ), not really too fussy because my dicing days are over and it is more for the sound and the looks and the thrill ! just waiting for a clutch plate from ebay which has not arrived in South Africa yet - been more than a month now..... I have just done the engine up,standard liners , new pistons , bearings etc.I have moved the battery to the boot already.Not sure how to post photo's if anybody wants to see.My garage looks like a floozys handbag...anybody looks for me , just follow the tools...I would have liked to transfer all the mechanical parts from a Holbay fastback over to the Rapiers body... |
| bigt80 |
Posted - 19 Apr 2010 : 17:15:46
quote:
Originally posted by janmarine3
Hi Guys,
I am new and watching and learning. I fitted a 1725 engine and matching synchro box in my 1960 Rapier that originally had the 1600 with twin Zeniths. I made up a 4 into 1 banana branch manifold , had a 36 DCD weber on which ran well. Now I am fitting twin weber 40 sidies, and they sit at an angle because of the manifold , will they operate ok pse ?
I have cut and re-welded the chassis to make space for rampipes & filters.
Mmmmm....I would have adapted the manifold, by cutting & re-welding to get them to sit flatter: rather than the trouble of fitting them in as is by cutting bodywork  . Usually move battery to boot/trunk in this mod to gain extra clearance. It has been done successfully, so it will just take a bit of sorting  & as others have posted: it is better to have them fairly horizontal I believe. Fastback engines are canted 10degs, but I think on Holbay they're not quite as this angle. Welcome to the forum BTW!  Cheers. G. |
| TurboZed |
Posted - 19 Apr 2010 : 00:50:31
I think you need to get them fairly flat. I remember the guy who made manifolds for twin side draughts for Fiat twin cam engines said he had to make a different design for one fitted in Lancias because they wouldn't work sitting at an angle.
Regards,
Jim Gough
Looking for a fastback Rapier.... |
| 1922 |
Posted - 18 Apr 2010 : 20:39:43
I guess you might have to tinker with the float level to get it to work right, but I've only used webers on the level (where the work great) so I can't say. The Alpine guys usually modify the manifold so the carbs are level. |
| janmarine3 |
Posted - 18 Apr 2010 : 10:12:54
Hi Guys,
I am new and watching and learning. I fitted a 1725 engine and matching synchro box in my 1960 Rapier that originally had the 1600 with twin Zeniths. I made up a 4 into 1 banana branch manifold , had a 36 DCD weber on which ran well. Now I am fitting twin weber 40 sidies, and they sit at an angle because of the manifold , will they operate ok pse ?
I have cut and re-welded the chassis to make space for rampipes & filters. |
| 1922 |
Posted - 30 Mar 2010 : 19:58:45
Sounds promising.
I've got a step further with my rack and pinion project (hopefully) after a couple of emails to the Avenger and Sunbeam Owners Club. |
| setchrapier |
Posted - 30 Mar 2010 : 19:21:58
Hi 1922
Great minds....
I discovered it last night and have ordered the inlet manifold they are having manufactured. This allows fitting of the 32/36DGV Weber which apparently is more effective/reliable etc than twin 40's. It also helps me with rallying regs.
Have a look at the thread on carburation...took me all night to wade through but v interesting.
will let you know how it all pans out.
Nick |
| 1922 |
Posted - 30 Mar 2010 : 18:21:01
I just had a look on the Sunbeam Alpine forum - they are a lot of posts about H120 engines and Weber carbs.
It looks like you can register as a 'non member'.
http://www.saoc.demon.co.uk/ |
| 1922 |
Posted - 29 Mar 2010 : 22:20:52
Someone like Reco-prop in Luton or Dave Mack in Coventry could shorten the prop but the later box has more, and smaller, splines on the output shaft so your prop won't fit into the gearbox.
The same applies to the input shaft, the later type has more splines so your clutch plate won't fit. I guess that you can use a Hunter one.
My worry was that the if the bellhousing is longer you are going to have trouble with bellhousing fouling the chassis and/or bulkhead. Not to mention the fun you might have with the rear gearbox mount and the gearstick
Looking at my Holbay manifold I would say it could be machined easily but all the Holbay engined Alpines I have seen use a very short inlet manifold - see http://www.askthemechanic.co.uk/classic-cars/sunbeam-alpine/more-performance.html
My manifold measures 80mm from face to face on the top and 87mm on the bottom.
Tyres - you might be asking the wrong guy. A fastback is supposed to have 165x13 (or 155 on the early ones!) - I use 195x15x15 on 7x15 rims  . |
| setchrapier |
Posted - 29 Mar 2010 : 16:45:09
1922, as ever you are great help.
I do have a Holbay engine complete and the bellhousing gbox from a fastback, so fingers crossed they are compatible length wise. If not (and longer), could I have the prop shaft shortened ?).
I don't mind too much re-arranging/re-siting elements of the underbonnet furniture to enable a neat fitting...if it looks right, it is right
If I end up fitting the engine upright and the inlet manifold fits lengthwise (with the 40's), I think I an right  that the manifold can be machined to make it flat faced, to take the webers perpendicular to the engine (hope this makes sense).
I insured the car (£43) FC for 10 months (multicar policy), max 3k miles pa and test drove it. Very smooth and surprising spritely...didn't push too much as the cross ply's look old and felt wierd when used to radials. Looking to change to radials of course and found Vredestein 175 85 15's at a reasonable price. A reasonable choice ? I don't want to 'over tyre' so wondered whether 165's might be better ? |
| 1922 |
Posted - 28 Mar 2010 : 22:02:40
To fit the engine canted you would need the Hunter type bellhousing. This will probably fit the gearbox but I have a feeling they are longer. You could possibly even use a Hunter/Rapier gearbox
What I could do is do some measuring for you. I've got an H120 clone in the garage and lots of fastback Rapier bits laying about so I could get in the garage and measure:
1 - Length of inlet manifold.
2 - Length of weber carb
3 - Length of bellhousing
4 - Length of gearbox input shaft.
I'll try to do this during the week (I'm using a fastback Rapier bellhousing as a door-stop so I won't even need to crawl under the car )
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| setchrapier |
Posted - 24 Mar 2010 : 18:13:13
1922, thanks for the excellent and helpful response.
My 1st concerns was that the engine mountings look different but I suspect might be transferable ie Rapier to Series and visa versa ? Is there any reason why I couldn't fit the engine into the Series but canted alla Fastback ?
Appreciate I would need to move battery to boot etc and ? other mods to make room for the Webers. I want to do all this without manifestly altering the car (so its a reversable option).
These Q's might be naive as I havn't 'helped myself' too much yet by analysing the situation. Thanks for patience if this is the case.
Mine is the 1592cc and the faster acceleration/compromised top end may suit, as all this is centred around classic rallying
The regs may disallow as this may be seen as a non period mod (I know I would need an MSA waiver for the Webers if I was allowed)
Nick
PS Currently rallying an Imp sport and having lots of fun,fancied abit more comfort though |
| 1922 |
Posted - 23 Mar 2010 : 20:17:43
I think it can be done.
I've certainly seen Holbay engines in Series Alpines where the main problem is finding space for inlet manifold and webers (the engines in fastbacks and hunters lean to the right for extra space).
The 1725 engine was fitted to the last series Rapiers, but upright, so the engine should go in. No idea if you will have space for the webers and air filters. I've have seen a special short inlet manifold used on a Series Alpine. If you need one custom made I know that Coltec do them - they got one made me one for me with extra large holes .
The fastback gearbox is very similar to the series box and some of the parts interchange so I would expect it all to work. The gearbox input and output shafts have more splines than on the series cars. I think the series clutch (or flywheel) will fit the Hunter/Rapier engine - though I'm not certain. The bellhousing on the Hunter/Rapier box is different to allow for the lean of the engine and it might be longer.
There are some small differences between the H120 running gear and the standard fastback Rapier, but that's only a different oil pressure in the overdrive a slightly larger mainshaft nut and a bigger 8.5" clutch.
But many years ago Holbay (the man himself) told me that the standard Hunter 7.5" clutch and gearbox was perfectly adequate and Rootes needn't have changed it.
I'm guessing that the back axle on you series car is geared for a 1500(?) so it's going to get 60 very quick but 100 will be loud!
Hope this helps. |
