19 replies to this topic

[Inno]

Hi there,

 

I posted few questions on other topics and tried to read as many as I could find about selecting right parts for a new engine.

 

I still have few concerns and would appreciate your help.

 

Target:

Not so slow (thanks Cooperman for that) road car (for weekend rides) with reliable engine, fun to drive, not too loud, compromise between bearable 80mph and exiting fun on a mountain roads and city drive – to feel response and acceleration.

 

Targeted numbers:

• A+ engine, 1292ccm
• CR – 10.1:1
• Up to 85-90bhp around 6000 and
• More important 90lb/s of torque starting from low rpm - 2500rpm – with the peak at 3500rpm - torque at lower rpm is a focus (thanks Cooperman again)

 

Choice of components – feel free to comment:

• Hif44 – newly rebuilt by DGS Carburation, red spring & BDL
• K&N  - original air box with an K&N element filter (more quieter and less sensitive on temperature change especially during cold weather)
• Alloy inlet manifold (Minispares) – ported/polished
• Intake valves 35.7 (36)
• Ported head - slightly
• Rocker assembly – original 1275 pressed steel 1:27 (1:29) – best original as I heard
• Light flywheel – probably from 998 (almost half weight comparing to 1275)
• Balanced crankshaft and pistons (lightened a bit if possible)
• Mniflow Cooper freeflow exhaust manifold (more quite than LCB and enough flow below 100HP)
• RC40 center exit with a middle box
• Pre-Verto standard clutch
• Dif – 3.2/ 3.1 (would like to have some smooth ride at 70-80mph) – I also have shorter Dif that I can use accordingly

 

To be defined – would appreciate your opinion and advise:

 

• Yelow Aldon with vacuum advance or Megajolt – to be defined (more research is needed) – thinking that Aldon may be enough since it is only engine with carburetor so Megajolt capabilities might not be utilized totally

 

• Pistons +20 I have but not sure what would CR so I may need to buy new +40 (1310ccm) – manufacturer to be defined – don’t need race or too expensive pistons…max range around £300 (Minispares, SW,…)

 

• Camshaft with springs and followers – to be defined – my biggest concern, what would be the optimum choice with my configuration (rockers) and targeted performance (high torque at low rpm), considering all camshafts below are within the budget (SW is almost 2.5 times more expensive than EVO1) – but I do it once so don’t want to be sorry later on because wanted to I save £100:
  • Sw5-07 – 250° with 0.350” lift with standard rockers (1.27 rockers may give a bit more lift)
  • Kent 266 - 270° with 0.320” lift
  • Kent 246 - 252° with 0.348” lift
  • Evo 1 - 264° with 0.327” lift
  • Piper 270 - 270° with 0.405” lift (not defined with what rockers)
  • AC Dodds – can’t find any specifications

 

Considering this SW5-07 and Kent 246 may give similar performance and may be  good choice for what I need - more torque with low rpm and smooth operation on low rpm.

...and SW5-07 is in general favorable cam on this forum.....I have a feeling that Evo 1 comparing to SW05 missing a bit of lift and a bit of torque at lower rpm...

 

Thanks in advance! 

Edited by Inno, 10 November 2018 - 03:57 PM.

[nicklouse]

flywheels are the same weight 1275 or 998 they are the same.

 

and if you change to pre Verto then dont forget the new arm, slave and whole clutch assy.

 

Cam Evo 1.

 

compresion is a bit high but you will need to measure and work out  and have block and/or head machined to suit.

 

dizzy/ignition mappable is good but not really needed. standard A+ electronic dizzy adjusted to suit build is fine.

[Inno]

flywheels are the same weight 1275 or 998 they are the same.

 

and if you change to pre Verto then dont forget the new arm, slave and whole clutch assy.

 

Cam Evo 1.

 

compresion is a bit high but you will need to measure and work out  and have block and/or head machined to suit.

 

dizzy/ignition mappable is good but not really needed. standard A+ electronic dizzy adjusted to suit build is fine.

thanks,  I have been told 998 flywheel is much lighter....I may the do some machine work or buy something from Minispares...

 

....so EVO 1 can do the job even if all others are within my budget?

[Inno]

 

flywheels are the same weight 1275 or 998 they are the same.

 

and if you change to pre Verto then dont forget the new arm, slave and whole clutch assy.

 

Cam Evo 1.

 

compresion is a bit high but you will need to measure and work out  and have block and/or head machined to suit.

 

dizzy/ignition mappable is good but not really needed. standard A+ electronic dizzy adjusted to suit build is fine.

thanks,  I have been told 998 flywheel is much lighter....I may the do some machine work or buy something from Minispares...

 

....so EVO 1 can do the job even if all others are within my budget?

 

..what would you suggest regarding CR?

[Retroman]

Evo 001 cam with some Calver ST 1.4 rockers, gives it a bit more lift

 

The cam needs advancing about 4 degrees too again to pull the lower end up

 

SW5 and 246 will not give you the sort of power you are after

 

You will need a decent head with 3 angle valve seats...they help pull the torque up at lower revs

 

as do rimflow valves, but they ain't cheap

 

An uprated clutch would be advisable, as in an orange pre-verto, but they are not available for the for-see-able

 

A good alternative is a lightened and uprated verto flywheel, with a solid centre plate which will do the job.

 

 

PM me if you want prices I can beat the rest.

[RooBoonix]

Continuing from retroman above, I think in one of Vizards books he gives a drawing for modifying standard valves, to give a back cut to improve flow. So if you have the equipment and time to do them rather than spend loads on rimflows, it may help a bit

[Inno]

Continuing from retroman above, I think in one of Vizards books he gives a drawing for modifying standard valves, to give a back cut to improve flow. So if you have the equipment and time to do them rather than spend loads on rimflows, it may help a bit

..I saw those drawings of 3 angle valve seat and watched Vizard's explanations.... but I need to see who can do that around me. Unfortunately sending parts to UK to do the machine job is far to expensive...it may be cheaper to buy rimflows....

[Inno]

Evo 001 cam with some Calver ST 1.4 rockers, gives it a bit more lift

 

The cam needs advancing about 4 degrees too again to pull the lower end up

 

SW5 and 246 will not give you the sort of power you are after

 

You will need a decent head with 3 angle valve seats...they help pull the torque up at lower revs

 

as do rimflow valves, but they ain't cheap

 

An uprated clutch would be advisable, as in an orange pre-verto, but they are not available for the for-see-able

 

A good alternative is a lightened and uprated verto flywheel, with a solid centre plate which will do the job.

 

 

PM me if you want prices I can beat the rest.

thanks...I am will try to avoid new rockers with higher ratio and see if it can be done with any available cam...PM sent

[Turbo Phil]

For the minimal cost/work involved a simple 30deg back cut on the intake valve is one of the single best modifications you can do. I wouldn't bother with the Rimflows, though they're good, with your chosen spec you'll see no real benefit as you're not using a lot of overlap.

Phil.

Edited by Turbo Phil, 11 November 2018 - 09:46 AM.

[Inno]

For the minimal cost/work involved a simple 30deg back cut on the intake valve is one of the single best modifications you can do. I wouldn't bother with the Rimflows, though they're good, with your chosen spec you'll see no real benefit as you're not using a lot of overlap.

Phil.

thanks!

[Retroman]

Rather than shelling out on the Rimflows and or higher ratio rockers, some offset rocker bushes would give some extra lift

 

A lot cheaper than a rocker set they are a good reliable mod

[Inno]

Rather than shelling out on the Rimflows and or higher ratio rockers, some offset rocker bushes would give some extra lift

 

A lot cheaper than a rocker set they are a good reliable mod

Thanks!

What would be recommended offset rocker bushes for pressed steel 1.27 original rockers?

[Inno]

For the minimal cost/work involved a simple 30deg back cut on the intake valve is one of the single best modifications you can do. I wouldn't bother with the Rimflows, though they're good, with your chosen spec you'll see no real benefit as you're not using a lot of overlap.

Phil.

Can I do that with any valves on the market? Plan to buy Minispares:

http://www.minispare...|Back to search

[Retroman]

 

Rather than shelling out on the Rimflows and or higher ratio rockers, some offset rocker bushes would give some extra lift

 

A lot cheaper than a rocker set they are a good reliable mod

Thanks!

What would be recommended offset rocker bushes for pressed steel 1.27 original rockers?

 

 

http://www.retromini...roducts_id=1255

 

PM for 10% TMF discount

[Turbo Phil]

You could use those valves which already have the back cut done, or if you have access to a lathe you could save yourself a decent amount of money and use the road spec valves and simply add a back cut to these. Unless you're planning on hitting 6,500rpm + on a regular basis the road spec valves will be fine.

Phil.

Edited by Turbo Phil, 13 November 2018 - 02:52 PM.