4 replies to this topic

[Derry100]

Sorry to bore you with a topic I'm sure you have discussed many time, however I have found it difficult to get a definite answer

Basically I have a cooper spi the engine has been stripped with the block bored +20, head skimmed and crank polished, pretty basic stuff

I have a Kent Md274 cam
I have so aquired some 1.5 roller tip rockers I believe minispares
Maniflow stage 1 kit with cat no other mods, standard head

The question I have is will the cam and rockers work ok
I have been advised to install double springs, I've also read xdrilled followers

What is your views on this, should I just fit the standard rockers

Thanks Rob

[TimNeal]

Sorry to bore you with a topic I'm sure you have discussed many time, however I have found it difficult to get a definite answer

Basically I have a cooper spi the engine has been stripped with the block bored +20, head skimmed and crank polished, pretty basic stuff

I have a Kent Md274 cam
I have so aquired some 1.5 roller tip rockers I believe minispares
Maniflow stage 1 kit with cat no other mods, standard head

The question I have is will the cam and rockers work ok
I have been advised to install double springs, I've also read xdrilled followers

What is your views on this, should I just fit the standard rockers

Thanks Rob

I have an MPI, and its fitted with the MED S Works kit that was supplied with 1.5s from new.

Ive just rebuilt the engine with the MD274 and before putting the 1.5s on spoke with Steve at MED and he said no to the 1.5s, but to fit 1.3 rockers. 
The MEMs system ECU won't cope with higher lift cam and higer lift rockers. So Ive stuck with 1.3s and the car performs very nicely.

[ac427]

Sorry to bore you with a topic I'm sure you have discussed many time, however I have found it difficult to get a definite answer

Basically I have a cooper spi the engine has been stripped with the block bored +20, head skimmed and crank polished, pretty basic stuff

I have a Kent Md274 cam
I have so aquired some 1.5 roller tip rockers I believe minispares
Maniflow stage 1 kit with cat no other mods, standard head

The question I have is will the cam and rockers work ok
I have been advised to install double springs, I've also read xdrilled followers

What is your views on this, should I just fit the standard rockers

Thanks Rob

 

Keith Calver does some nice 1.4 rockers - https://www.calverst.com/

[Ethel]

I don't think they'd be good for an injected road car. Hi lifts give more lift everywhere, so it's like having a cam with more duration, which won't help with low end power or emissions & a 274 is already pretty racy for a road car.

 

Springs are less of an issue with higher ratio rockers as the leverage is better from the springs' POV for keeping the follower on the cam. Though they will get compressed more, so could bind (touch coils). Reduce the spring rate proportionally to meet the same spec

 

1.5/1.25= 1.2 so  160lb springs will feel like 190lb springs on the cam - even more at the higher lift.

 

You could compare the following with one of the swiftune cams that are supposed to be developed for hi lift rockers.

 

Part No  MD274

Application Power Band  SPORTS INJECTION 1000-6000

Cam lift .285”   .281”

Valve lift .348”   .343”

Duration 248°   274°

Valve timing 12/56 69/25

Duration @ 1mm lift 213°   231°

Full lift 112°

Valve clearance   .016”

Lift at tdc .023”  

[brivinci]

I have a custom cam made by Calver and am running a MED 1.5 rocker set. I cant recommend both things more...just not together. Calver did NOT recommend running the 1.5's but I had them and wanted to give it a go. Could be something else but the car currently has a strange dead spot between 3500-4000rpm. Once past 4, and if you stay on or above, it rips. It doesnt seem to be as apparent in 1st and 2nd gear. The long and short of it, I would be much happier had I went with the 1.3...and still not sure why I didn't still.