Forget 1.5 rockers on any 1098, even a tuned one- but 1.3 roller tips are worth getting.
As for 1.7s, most people say they don't even work good on race 1380s.
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| 1.5 Rockers & a Question. https://www.ausmini.com/forums/viewtopic.php?f=2&t=62915 |
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| Author: | blake12345 [ Thu May 06, 2010 2:18 pm ] |
| Post subject: | 1.5 Rockers & a Question. |
Hey, im looking at some more performance bits and pieces for the mini. I was thinking of maybe getting some new rockers and was wondering if i brought some 1.5:1 Rockers do i need to make any mods to make them work? Also what about 1.7:1 Rockers are these worth having a look at? The reason im wanting to do more mods is that im chasing the 100hp mark with my 1098cc without a charger (im thinking first target is to get this at the crank)! Am i being stupid in aiming for this? Is it possible with a 1098 to get this kind of power? i currently have around 70@ the crank Thanks Blake |
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| Author: | drmini in aust [ Thu May 06, 2010 5:28 pm ] |
| Post subject: | |
Forget 1.5 rockers on any 1098, even a tuned one- but 1.3 roller tips are worth getting.
As for 1.7s, most people say they don't even work good on race 1380s. |
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| Author: | Wombat [ Thu May 06, 2010 5:46 pm ] |
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And the Doc will turn your standard rockers into 1.3 (for a price) |
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| Author: | blake12345 [ Thu May 06, 2010 6:50 pm ] |
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Ok then i will look into the 1.3 then. What are a standard set of rockers? |
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| Author: | drmini in aust [ Thu May 06, 2010 7:34 pm ] |
| Post subject: | |
blake12345 wrote: Ok then i will look into the 1.3 then. What are a standard set of rockers?
I can't find my docs or the post on ausmini where I compared them, so am going by my memory- I used an RE13 cam (.290" lobe lift) and a new thick wall rocker shaft in this comparison. In order, from worst lift ratio first: Cooper S forged rocker, 1.16:1 `A+' (but used here in A series from ~1975 on) sintered rocker, 1.18:1 Pressed steel rocker, smallbore (round pads) 1.21:1 with stock bushes, 1.31:1 (with .044" offset bushes)* Pressed steel rocker, 1275 (oval pads) 1.25:1 with stock bushes (estimate), 1.34:1 (with .044" offset bushes)* * Note that I only make the offset bushed rocker sets to order, as they are now about as expensive as buying 1.3 roller tips from UK. |
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| Author: | blake12345 [ Thu May 06, 2010 8:32 pm ] |
| Post subject: | |
ok thanks. So is there much difference between using the offset bushes or just buying the 1.3 rockers? |
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| Author: | drmini in aust [ Thu May 06, 2010 8:56 pm ] |
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blake12345 wrote: ok thanks. So is there much difference between using the offset bushes or just buying the 1.3 rockers?
1.3 roller rockers are more likely to all be the exact same lift. I was offset bushing the rockers because rollers from UK were expensive, but they are a lot cheaper now with current exchange rate. Here's what my modified ones looked like with the bushes fitted- the 4 rocker pillars are also bushed to move the shaft back 1.6mm. 
Boring the bushes to size, .0005" (1/2 a thou) clearance on shaft, after pressing them into the rockers- 
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| Author: | Lillee [ Fri May 07, 2010 12:30 pm ] |
| Post subject: | Re: 1.5 Rockers & a Question. |
blake12345 wrote: The reason im wanting to do more mods is that im chasing the 100hp mark with my 1098cc without a charger (im thinking first target is to get this at the crank)! Am i being stupid in aiming for this? Is it possible with a 1098 to get this kind of power? i currently have around 70@ the crank Thanks Blake Possible with a 1098 but very unlikely without taking the thing out and starting the build from ground up starting with a big bore out to say 1152 or something like that. Big cam. But most of the money and ponies are in the head so your 202 will need substantial porting, chamber and valve work to achieve 100bhp. Rockers and cam is a fine balance. Can't just whack on rockers and expect drastic hp increase. It could even go backwards in the case of 1.7's. If you are serious (and have the wallet to back it up) give Graham Russell a call. |
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| Author: | blake12345 [ Fri May 07, 2010 2:03 pm ] |
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Yeh GR has done a rebuild on it and has only done 700k's since. So its still new. Its been bored to 1172 and it has a 202 head that has had a small amount of work done on it already. Im not sure on the cam thats in it but it pulls from around 2500rpm up to around 5500rpm but isnt to lumpy. It does struggle to idle much below 1000rpm but yeh so its had a fair bit of work done but im still wanting more. Ive seen plenty of 998cc making good power and cant see why a 1098 cant! So i thought id give it a go. but yeh i know just rockers wont get me heaps but its these little things that make a different. Im planning on taking my head up to GR sometime soon for some more work on it and with my new exhaust coming soon, and my DHLA setup properly it should make the car a lot better |
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| Author: | simon k [ Fri May 07, 2010 2:44 pm ] |
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don't buy anything new until you have the car running spot on as-is. If GR built the motor only 700km ago, but the carb and exhaust isn't right then it'd probably making a significant amount less power than it's capable of. Take it up to Greig and get it sorted, then upgrade |
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| Author: | blake12345 [ Fri May 07, 2010 4:29 pm ] |
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Yeh im not planning on doing anythig for a little bit yet im just doing the ground work and finding out what i should do and the like so i can get it all ready. My exhaust is on its way and the carb i think it is running ok. I had the car dyno tuned a month ago and the setup is where we left it. I just want to put some bigger chokes in as i only have 32mm at the present and i want to put 33mm chokes in. but yeh im going to do abit more driving then take it back in for another tune then i'll start tuning even more. |
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