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 Post subject: 1275 12H Options
PostPosted: Tue May 26, 2015 7:07 pm 
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848cc
848cc

Joined: Thu May 14, 2015 9:57 pm
Posts: 169
Location: SE Melbourne
Hi All,

You guys are awesome and inspiring. There's so much knowledge here, but at the same time it's a bit intimidating for a newbie to determine what path to take.
We (My son with my help) have a 78 1275LS that is pretty original apart from some front body damage. We are presently looking into getting this repaired, but the rest of the car needs a refresh as a minimum and a rebuild maybe.

Would like some advice on our options for the engine/gearbox.
It's my sons car and was running till about 3 years ago when shunted by a third party hit and run.
He reports that as far as he is aware the engine hasn't been reco'd at any stage.

So, to the questions:
- What are the thoughts on engine rebuild. Will be road driven but not as a daily.
- A mild cam and some extra oompph would be good. Whats the "best" way to achieve this economically
- Is the std LS head worth using or are there other options. (Not sure which head it is)
- Is unleaded valve seats a "good" option
- Single carb or convert to twin SU's ?
- Gearbox ? Reportedly has synchro issues. Is this a job we could do ?


Sorry for the mind dump, but hey, we are starting at the beginning and dont want to waste our efforts.

_________________
'78 1275 LS (Under Repair, Dependant #1's car)
'72 GT Powered Clubman (Mine)... Under (re) construction


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 Post subject: Re: 1275 12H Options
PostPosted: Tue May 26, 2015 8:38 pm 
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1275cc
1275cc
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Joined: Thu May 24, 2007 7:19 pm
Posts: 5370
Location: Yandina,Sunshine Coast,QLD
The power is in the head, get it breathing and you get more power easy.
A single SU carby will be fine maybe a HIF4, the more modern version of the SU and it will feed a 1275 engine fine.
Unleaded hear conversion is a good idea while the head is getting rebuilt.

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Respect mine and I'll respect yours.


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 Post subject: Re: 1275 12H Options
PostPosted: Wed May 27, 2015 10:51 am 
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religious status
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Joined: Fri Mar 19, 2004 6:19 pm
Posts: 39754
Location: near Baulkham Hills, NSW
Power (with good torque) is not all just in the head, it is more in the cam + carby these days.
Stock, the 1275LS was about 59HP; nowadays you can get over 100HP at the crank with a single HS6 or HIF44 SU, and stock 1275LS head porting, just with Mk2S intake valves fitted. Using an RE13, RE83 or RE266S cam. Use 1.3 or 1.5 rockers (1.3 on the 83).
The stock 1275LS cam is pretty useless if you are chasing good power.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject: Re: 1275 12H Options
PostPosted: Wed May 27, 2015 12:33 pm 
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848cc
848cc

Joined: Thu May 14, 2015 9:57 pm
Posts: 169
Location: SE Melbourne
Thanks Guys.
More to chew over. Not chasing big power Doc, If we left the head alone and concentrated on block refresh it may suit our economics. Dont want to waste our efforts tho '

So much to learn !

_________________
'78 1275 LS (Under Repair, Dependant #1's car)
'72 GT Powered Clubman (Mine)... Under (re) construction


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