46 replies to this topic

[Jase]

Thanks, decided to spend a little more e.g new twin HS4s, last question from me (I hope) on this thread. But do I have to separate the engine from the gearbox to replace the cam?

[Retroman]

If you are buying twin HS4's new its more than a bit, the last set I sold was £598 ready to fit with manifold and they are currently unavailable.

The last Visarded HIF 44 I did came out at £315 ready to fit with manifold.

 

If you know its not a spider drive cam it can be changed without splitting engine/box on 998 1098 and Cooper S blocks but I suspect you have a solid wall 1275 block so the only way to change the cam is spit it and turn it upside down to remove the cam.

The reason being the followers cannot come out with the cam in and the cam cannot come out with the followers sitting on the lobes.

[Jase]

Thanks Retroman, yes that's what I was budgeting for on top of the other mods. Worth the extra I think.

[Retroman]

PM me when you need them, I can beat most on price.

[Turbo Phil]

You want to be fitting new followers with a new cam anyway.

Phil.

[Jase]

So I'll guess I'll ist my twin 11/4s for sale shortly. I've even bought the refurb kit as well :)

[Dusky]

Fitting a new cam without changing the followers Will gain you the first few minutes. After that the cam Will be ground into nothingness anyway.

[carbon]

I have a brand new 1275 Spi engine sitting in my garage for my GT build. I don't want to for any serious internal work but I'm open to modifying it.

 

I want to fit 1^_1/4" twin carbs, there is no injection with the engine as it was one of the last brand new ones to leave Longbridge. I'm going to have to replace the distributor but pretty much open to anything else such as new flywheel etc etc.

 

In terms of use I just want something that will be reliable, will be able to keep up with modern traffic and if possible have a bit of a boost when needed.

 

Budget - up to £1k

 

Thanks

 

If it's a brand new SPI unit, never been touched or run then the followers would be mint and with slot drive cam? Could change cam without splitting from gearbox by draining oil turning unit upside down and then pulling cam out carefully. But I have never tried this...

[Jase]

Yep, never been fired up. I'll stick with the simpler mods. I will probably only do about 500 miles a year in it.

[carbon]

Thanks, decided to spend a little more e.g new twin HS4s, last question from me (I hope) on this thread. But do I have to separate the engine from the gearbox to replace the cam?

From what you described twin HS2s would have been more than adequate. But it's your car.

 

To do twin HS4s justice consider fitting fast road cam along with 1.4 or 1.5 rockers, and a very well ported head from Turbo Phil, AC Dodd, Brett Sims, or similar reputable source. And make sure the HS4s are hanging off a Maniflow inlet and fitted with K&N or similar filters and stub stacks.

 

Also think about the gearing and final drive ratio, as this will start to become more critical for satisfying driving experience.

[Retroman]

Fitting a new cam without changing the followers Will gain you the first few minutes. After that the cam Will be ground into nothingness anyway.

Not strictly true.

   I have done 2 1275 cam swaps in car without changing the followers and neither had an issue. Both mild cammed road cars where the followers were known to be good quality to start with and had done little mileage. DV and DA at APT used to do it all the time, slightly different scenario but they were caning them on the dyno. Its not normal practice and only done as a very last resort.

 

   The best or worst ? case of new cam / old followers I ever came across was an ex works 998 which had a full rebuild by an (allegedly) good engine builder. On stripping the engine which had only done a few events, what was a new 649 cam was unharmed and the followers were worn like egg timers, and had obviously seen some serious revs and use over time. Why he had not put new followers in on a full and not cheap 998 rebuild I will never know. The customer was not brave enough to ask him.

[Minigman]

Thanks, decided to spend a little more e.g new twin HS4s, last question from me (I hope) on this thread. But do I have to separate the engine from the gearbox to replace the cam?

From what you described twin HS2s would have been more than adequate. But it's your car.
 
To do twin HS4s justice consider fitting fast road cam along with 1.4 or 1.5 rockers, and a very well ported head from Turbo Phil, AC Dodd, Brett Sims, or similar reputable source. And make sure the HS4s are hanging off a Maniflow inlet and fitted with K&N or similar filters and stub stacks.
 
Also think about the gearing and final drive ratio, as this will start to become more critical for satisfying driving experience.

[Jase]

 

Thanks, decided to spend a little more e.g new twin HS4s, last question from me (I hope) on this thread. But do I have to separate the engine from the gearbox to replace the cam?

From what you described twin HS2s would have been more than adequate. But it's your car.

 

To do twin HS4s justice consider fitting fast road cam along with 1.4 or 1.5 rockers, and a very well ported head from Turbo Phil, AC Dodd, Brett Sims, or similar reputable source. And make sure the HS4s are hanging off a Maniflow inlet and fitted with K&N or similar filters and stub stacks.

 

Also think about the gearing and final drive ratio, as this will start to become more critical for satisfying driving experience.

 

 

I knew all of this would be very confusing. I'll do some more research and make a decision later in the year.

[Minigman]

Can I pick your brains Carbon?

Why would you fit 1.5 rockers and also do a fast road cam? I always thought higher lift rockers were used as an easy non invasive way to gain more lift when the cam is standard.

[grizzler73]

You can get good power with 1 1/4" SU'S if vizardised and set up right, This Arkley SS has won the under 1300 class in the HSCC for the last 2 years. A series engines have to run the smaller SU'S.