I've been drooling over the Minispares catalogue as I saw they had a Christmas sale.

My specific question is in regard to these:
ROCKER ASSEMBLY 1.3 RATIO 1275cc FULL ROLLER ROCKERS
C-AHT437



As my car is a road car, and not a track car, I already know I don't want the engine characteristics of 1.5:1 roller rockers, (based on what I've read).

It's currently got some headwork, cam, weber, extractors. My question is what difference am I going to notice with 1.3:1 rockers over the standard 1275 A+ item? Or am I better off investing my hard earned $ on other things.

What ratio are 1275 A+ rockers anyway?

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1970 Mini Deluxe - 1275, Weber, Clive 346 cam, MS 4-pot slotted discs, Megajolt ignition Now with new improved Mambas... almost on the road
1966 Van with Traveller rear seat conversion
2008 Prado GXL
All in various states of repair...

Standard ones are 1.25 or 1.3 I think, of you want an upgrade its 1.5 or nothing.

Yes 1.3 roller rockers are worth having, as long as you don't pay silly money.
FYI,
A+ rockers have the lowest lift, only S forged rockers have less.

Here's the lift figures, the head was a 12G1316 (1275 smog head) much the same as a 940 as a 12G940..

Rocker ratio = (valve lift " + .016" clearance)/.290" lobe lift

22/7/07 Checked valve lift- 12G1316 head fully assembled.
RE13 cam, stock pushrod, valve clearance .016”:
Lift at #1 inlet valve-
S forged rockers lift 0.321”, rocker ratio= 1.16:1

A+ sintered rockers lift 0.327”, rocker ratio= 1.18:1

998 Deluxe rockers, std cast iron posts, lift 0.337”, rocker ratio= 1.22:1

998 Deluxe rockers, with A+ sintered posts (are 0.3mm shorter than CI) lift 0.339” , rocker ratio= 1.22:1

* 998 Deluxe rockers, cast posts lowered 0.6mm, offset bushed 1.0mm, lift 0.359”, rocker ratio= 1.29:1

* 998 Deluxe rockers, cast posts lowered 0.6mm, offset bushed 1.1mm, lift 0.365”, rocker ratio= 1.31:1

Toyota Corolla rockers, late `sintered rocker’ type posts, shaft offset 3.9mm back, lift 0.402”, rocker ratio= 1.44:1

Noter the offset bushes in * above were mine, bored from solid after pressing in, the offset ones you buy have less offset so less ratio.

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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.

Here is a little cheat sheet I made up a while ago to identify some rockers and their ratios.

Here's what Corollas look like- bushed & fitted to a Mini shaft, with offset rocker posts to move the shaft back.
Ratio 1.44:1.
[edit] I used to make these up years ago, but it's a lot of work to do properly; recently you could buy MSC forged 1.5s cheaper.



Top view- Corollas at top, S forged ones below.

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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.

I see Keith Calver is selling 1.4:1 rockers:
on their own
http://dt-vps.co.uk/calverst.com/cart/index.php?route=product/product&path=60&product_id=81

and in a kit minus the rocker shaft.
http://dt-vps.co.uk/calverst.com/cart/index.php?route=product/product&path=60&product_id=132

So.... what ratio is advisable for a road car? From what I can gather 1.5:1 on a 1275 motor is you gain performance at high rpm but lose low end performance.

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1970 Mini Deluxe - 1275, Weber, Clive 346 cam, MS 4-pot slotted discs, Megajolt ignition Now with new improved Mambas... almost on the road
1966 Van with Traveller rear seat conversion
2008 Prado GXL
All in various states of repair...

Been asking the same questions for a MK2 Cooper S

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1970 MK2 Cooper S

I'd go 1.4s if you can get them. Even 1.5s go well on short duration cams, they don't lose much bottom end on a 1275.
They work fine on RE266, RE266SS, RE13, heck they are even great on my RE282..!! I won't swap em for 1.3s...

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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.

So what about these ones from Jon Speed Racing
112 pounds
http://www.jonspeedracing.co.uk/index.p ... &cID=13895

Anyone bought and used these

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1970 MK2 Cooper S

Also if fitting the 1mm offset bushes to cooper S rockers
What ratio would i end up with

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1970 MK2 Cooper S

By my calculations, using numbers above, you will get around 1.226:1.

You will find places in the UK advertising that fitting offset bushes give you 1.5:1. It is total BS.
And, last time I looked, the offset rocker [edit] bushes you can buy were only .032" or .035" offset. Not .040" (1.0mm).

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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.

Do all of these fit under a standard rocker cover? Or is that another modification that would be required?

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1970 Mini Deluxe - 1275, Weber, Clive 346 cam, MS 4-pot slotted discs, Megajolt ignition Now with new improved Mambas... almost on the road
1966 Van with Traveller rear seat conversion
2008 Prado GXL
All in various states of repair...

Yes, they all fit.
Some roller sets don't fit under some alloy covers they say, but I've never seen that. I suspect it's with the later, angled covers.

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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.

This whole rocker thing.....

Whether hi-lift rockers are worth fitting depends on whether the camshaft you are using was DESIGNED to use them. Typically older BMC sports profkles were not. Most of Piper's range were not. Kents 'MD' range were. Well - supposedly. Only 2 of that cam range were actually properly developed, the rest were best guesses based on the resuts from those two cams. They were the 266 and 286... hence they were they only two written up with results in a certain persons 'Bible'. Most of Graham Russell's cams are.

S forged rockers are junk - they do not make anything like te ratio they are suppsed to, and are horrendously inconsistent. the pressed steel rockers achieve more lift consistently, but are also seriously inconsistent. The currently available forged 1.5 rockers are all over the place ratio wise (up to 1.63:1 in some cases) and the pads are rarely square to the valve tip. Most roller tip rockers are decent when new, but because of teh stupid fight for cheapest cost, quality isn't what it should be. After some half dozen races the pins/rollers wear so you end up with variable valve timing. All very disappointing.

Somebody said they ordered a set of my 1.4:1 rockers then gave up and had to have a refund. Don't recall that one, and it must have been only one... I have sold out very quickly of the first 3 batches I have had made. At least half of them going to Swiftune.. they love 'em. I am currently out of stock but the next batch will be through just after Christmas. I can not afford to have a mega-huge batch done. And it would slow stock availability anyway.

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Tuning should always be a compromise between what is possible and what is necessary.
www.calverst.com

I have a set made to Kevins design. The lift is across all lobes is consistent you cannot bet the Japenese for quality

The cam is a re13 direct from Gr which I also measured and was consistent across the lobes.

The consistent lift made a real noticeable difference to my engine.

Kiwiinwgtn