30 replies to this topic

[ACDodd]

There are some who have tried 1.5 rockers on the RS cam, they get stunning results. However I do not recommend the use of these on my road cams due to increases in wear.

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Edited by ACDodd, 28 August 2017 - 09:26 AM.

[racingbob]

This engine belongs to Kay from miniworld. It too features an RS cam this one uses a 1330 bottom end as above but only a 33mm inlet valve, and uses twin hs4 carbs and minisport 1.3roller tip rockers.

your rs cam seemed to give more torque than an mg metro but similar hp does that sound right

[ACDodd]

Mine also does it with less rocker ratio. Pulls harder everywhere in the rev range.

Ac

[racingbob]

Mine also does it with less rocker ratio. Pulls harder everywhere in the rev range.

Ac

oooh that sounds good been looking at my Gragh yes it does seem so

[neal]

So, over a period of 10 years I developed my version of his cam, with less overlap lift less duration, but much more lobe lift. I called it the ACD - RS cam. The lower lines on the graph here represent before and after dyno tuning by myself. This engine used minisport 1.3 roller tip rockers.

Ac, what were compression ratios for the three RR sheets, were the cylinder heads very similar in design (33mm inlet duly noted on Kays head) and can you remember what was the ignition timing was.

 

I do like the look of your RS cam but can you give me some details  as well for your RS+ (a RR printout would be great)

 

Cheers, Neal

[ACDodd]

All those RS graphs are at 9.75:1 compression. The maximum recommended for the RS cam. Maximum ignition advance is almost always 30degrees max advance from 4krpm. The first graph was a head cut by me, using only a single angle valve seat (aanother version of which did 125bhp with a 296 cam). This head with a 266 cam also had 10.5:1 compression. It was the last road engine I ever built with a compression over 10:1 which was many years ago. All were fully ported heads using 35.6 x 29.4mm valves except kays which used 33.3 x 29.4mm. All engines used 95ron fuel.

In my testing Bobs engine would have gone better still with lower compression.
PM me your email address and I'll send you some more info.

Ac

Edited by ACDodd, 28 August 2017 - 08:37 PM.

[neal]

All those RS graphs are at 9.75:1 compression. The maximum recommended for the RS cam. Maximum ignition advance is almost always 30degrees max advance from 4krpm. The first graph was a head cut by me, using only a single angle valve seat (aanother version of which did 125bhp with a 296 cam). This head with a 266 cam also had 10.5:1 compression. It was the last road engine I ever built with a compression over 10:1 which was many years ago. All were fully ported heads using 35.6 x 29.4mm valves except kays which used 33.3 x 29.4mm. All engines used 95ron fuel.

In my testing Bobs engine would have gone better still with lower compression.

Ac

Cheers Ac

 

I'm in the process of cutting a head for someone else who is interested in your cam, I'll follow your advise on 9.75:1

 

Thanks again, Neal

[ACDodd]

Emails sent.

Ac

[neal]

Thanks Ac,

 

I must say I do like the look of the RS+

 

Kind Regards

 

Neal

[racingbob]

My mg metro cam in a 1275 is holding its own in hp till 6000- 6200 think it maybe loosing a bit torque down low compared to 266 and rs is that right they show realy high torque 2000 30009

[ACDodd]

The point is bob, your engine should be doing 93to 95hp with that spec.

Ac

[Allrounder]

Wonder if any dyno graphs around comparing these basic fast road cams. Makes you wonder if you would actually feel any difference over a mg metro ( I'm realy happy with the performance of the mg metro cam in my car) but hey gathering parts for short engine build soon

My 1310 with the kent 266 and 1.5 rockers for you to look at. Note its taken at the wheels with a fresh gearbox!

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Edited by Allrounder, 29 August 2017 - 08:25 PM.

[racingbob]

AC Be interesting to see graph between ac rs and rs+

[Geordie Bob]

Wonder if any dyno graphs around comparing these basic fast road cams. Makes you wonder if you would actually feel any difference over a mg metro ( I'm realy happy with the performance of the mg metro cam in my car) but hey gathering parts for short engine build soon

My 1310 with the kent 266 and 1.5 rockers for you to look at. Note its taken at the wheels with a fresh gearbox!

[Geordie Bob]

Wonder if any dyno graphs around comparing these basic fast road cams. Makes you wonder if you would actually feel any difference over a mg metro ( I'm realy happy with the performance of the mg metro cam in my car) but hey gathering parts for short engine build soon

My 1310 with the kent 266 and 1.5 rockers for you to look at. Note its taken at the wheels with a fresh gearbox!

Hi
Your engine is very similar to mine.
Do you know your compression ratio please and spark advances curve?
What fuel do you use also.
Thank you
Paul