24 replies to this topic

[JonnyAlpha]

Hi;

 

Spotted these 1.5 roller tip rockers for sale and before investing thought I'd ask for advice on here.

I have read up on the pros and cons on various designs in KC's great guide here, but cannot seem to identify the maker of these rockers?

 

This is for a new engine build, which I am doing myself, Metro 1275 A+, AC RS Camshaft, HIF44, Stage One Kit. Head is an early MG Metro with standard large valve but no other modifications yet. It will be getting some work (Stage 2 ish) once I can afford it (Remove valve guide bosses, new 3 step valves, new valve guides, springs etc (not gas flowed). 

 

Having just re-read AC's Cam specs, the Cam may not benefit from the increased Valve lift unless the head was gas flowed but that's just me making an uneducated assumption? 

 

Edited by JonnyAlpha, 24 February 2020 - 11:19 AM.

[Ethel]

They look a bit like the Minisport items, possibly an older version????

 

Bigger rockers increase the valve lift relative to the cam lift at all points between the valve opening & closing. The biggest advantage* is when the valve is just off its seat as that's where the restriction would be highest. Having excessive maximum lift won't hinder performance, but it wastes a bit off power compressing the valve springs and puts more stress on the valve train. Bigger ratio rockers magnify the valve spring force as much as they do the cam lift so you don't need as strong springs to keep the followers riding on the cam.

 

* higher initial lift  has a similar effect to increasing the cam's duration which is how you can end up losing performance if your cam is already providing as much duration as your application/ power band wants.

[Spider]

They are Mini Sport items and have a reputation for breaking.

 

<edit;-

>

Edited by Moke Spider, 24 February 2020 - 10:56 AM.

[JonnyAlpha]

Thanks for the heads up - yes they do look like the Mini Sport version. I think I'll go with the original Rocker Assembly (which needs strippiing and cleaning) and spend my money on the things I actually need - like a 2 core radiator, hoses, disc brakes, etc, etc, etc.

 

Always on the look out for a bargain though - hence the question  

[cooperd70]

Both Keith and AC supply their own specced rockers that are suitable for their cams for both 998 and 1275, if you fancy not stripping and cleaning the originals and maybe get some additional performance on the rebuild.

[wile e coyote]

Thanks for the heads up - yes they do look like the Mini Sport version. I think I'll go with the original Rocker Assembly (which needs strippiing and cleaning) and spend my money on the things I actually need - like a 2 core radiator, hoses, disc brakes, etc, etc, etc.

 

Always on the look out for a bargain though - hence the question

If you do reuse the original rockers then a new shaft is well worth the measly  cost.......minispares C-AEG399 rarely will 16 quid be better spent.....

[JonnyAlpha]

 

Thanks for the heads up - yes they do look like the Mini Sport version. I think I'll go with the original Rocker Assembly (which needs strippiing and cleaning) and spend my money on the things I actually need - like a 2 core radiator, hoses, disc brakes, etc, etc, etc.

 

Always on the look out for a bargain though - hence the question

If you do reuse the original rockers then a new shaft is well worth the measly  cost.......minispares C-AEG399 rarely will 16 quid be better spent.....

 

 

Thanks Wile - a worthwhile addition. 

 

This was the only pic I could find of my Rockers - they are tucked away in a box in the garage now, but I do need to get them out and check them. 

 

[gazza82]

They are the standard cast ones .. check the valve stem pads for wear.

 

There are three "standard" types:

 

• Pressed steel (which can be very strong with a small weld along the top edge seam I've been told)
   
• Cast (as in the pic above)
   
• Forged (only found on some of the Cooper engines)

[JonnyAlpha]

 

They are the standard cast ones .. check the valve stem pads for wear.

 

There are three "standard" types:

 

• Pressed steel (which can be very strong with a small weld along the top edge seam I've been told)
   
• Cast (as in the pic above)
   
• Forged (only found on some of the Cooper engines)

 

 

Gazza - I take it the Valve Stem Pads are the part of the rocker that pushes down on the valve itself?

[gazza82]

That's it ... seen a couple of those sets with lots of wear .. impossible to set the clearances

[JonnyAlpha]

That's it ... seen a couple of those sets with lots of wear .. impossible to set the clearances

 

I take these are the newer replacements?

[JonnyAlpha]

Just found these on Minispares, Forged assembly for £133

[croc7]

I like Calver's 1.4:1 rockers, pricey but a quality product.  If you are building the engine for torque, I'd go for a good set of forged 1.3:1 rockers rather than 1:5.  Calver's article on rockers is a good read.  He addresses type, use and accuracy of manufacture.

Edited by croc7, 26 February 2020 - 10:45 PM.

[JonnyAlpha]

I read Kieth’s article and wish MS did a 1.3 version. Did look at Kieth’s website - they are costly.

[gazza82]

Aren't standard forged rockers around 1.2/1.3? Assuming you can find a set ..