Roller lifters on a Rover?

crayefish · Post by **crayefish** » Mon Sep 21, 2009 8:12 pm

Has anyone ever tried fitting a set of roller lifters (probably from a sbc) into a Rover? A Roller cam could really help the torque...

I know the lifter bores need to be a bit taller for rollers, but perhaps a shorter set of roller lifters could be found?

I would be interested to hear peoples views on this. If people have tried this I might give it a go. If people havent, I might anyway if someone wants to donate a set of roller lifters!

HairbearTE · Post by **HairbearTE** » Mon Sep 21, 2009 9:59 pm

It's been mooted many times. V8 developements claim to have done it, I looked into it but the expense does stack up. You need a custom steel billet cam. The std rover one will last no time at all with the huge valve spring pressures required to run the roller. A better pushrod than those commonly available for the rover would be a good idea for the same reason. Fitting a rev kit is one route, but again that's big expense.
If you do go for it the lifters from a SBC chevy will fit physically but check the oiling provisions. One of the U.S. sites sells roller liufters for the buick V6 and when I asked they gave me a price for 8 for use with the rover, It was over $500 though.

crayefish · Post by **crayefish** » Tue Sep 22, 2009 8:05 am

dont suppose there is an american engine (sbc or sbf etc) where the camshaft could be made to fit the Rover? Surely a later buick cam would fit? The price of roller steel cams for chevys etc are not too different from flat tappet cams as the rollers are so common.

Also, chevy pushrods could be used, then the rockers converted to chevy oiling, or the holes blocked off?

Here is what I found on Summit:

Buick roller cam: (mechanical or hydraulic) $250-290
push rods: $50
Roller lifters: (mechanical or hydraulic) $190+

So in theory the parts could be bought for $500 or £400.

chodjinn · Post by **chodjinn** » Wed Sep 23, 2009 11:49 am

are you sure that roller cam isn't for the V6 though?

There's someplace in australia that do roller kits but they are like $2k I think.

Plus you'd need a rev kit, which will need to be custom, therefore silly expensive. I think BoostedLS1 looked into it a while back as well.

The expense vs benefit means generally it's not even worth thinking about. Spend the money on a dry sump.

crayefish · Post by **crayefish** » Wed Sep 23, 2009 12:14 pm

chodjinn wrote:are you sure that roller cam isn't for the V6 though?

There's someplace in australia that do roller kits but they are like $2k I think.

Plus you'd need a rev kit, which will need to be custom, therefore silly expensive. I think BoostedLS1 looked into it a while back as well.

The expense vs benefit means generally it's not even worth thinking about. Spend the money on a dry sump.

No the cam is for the larger capacity buick V8s... its possible it might fit...

Also, why would the rev kit be needed if all the other components could be retro fitted (translate as bodged!) in?

If an american cam can be found to fit and the oiling for the lifters could be sorted, it would work out at only $500...

chodjinn · Post by **chodjinn** » Wed Sep 23, 2009 12:16 pm

there definitely is more to it than that, if it was that cheap everyone would be doing it.

You need cam, lifters, pushrods, roller rockers, then there's all the machine work to make it fit . . . there was some discussion on this in my uber-build thread a while ago, but can't find the link now.

spend · Post by **spend** » Wed Sep 23, 2009 1:38 pm

You can have hydraulic roller cams as well. I don't see this argument about massive spring pressures, surely that is confusing racing cams with road cams? Just seems to me like it would be a lot easier for springs to keep a roller on the cam than a spinning flat tappet? Start adding aggressive cam profiles, bigger heavier valves, 1000s more rpms and you change the goalposts dramatically either roller or flat;)

chodjinn · Post by **chodjinn** » Wed Sep 23, 2009 1:55 pm

Flat tappet cams can only go so far in terms of spring pressures that they can cope with. Roller cams are used for full-on race engines.

Roller cams and tappets allow much higher spring rates to be used, therefore allowing more lift etc on the valves, which is needed in race engines to maximise the power.

There isn't much point in having roller cams/tappets in a road engine is there? It would be a pig to drive.

I would have thought the order is something like this;

Hydraulic - Road/Mild Race
Solid - Fast Road/Race/mild Drag
Roller - Full race/drag

spend · Post by **spend** » Wed Sep 23, 2009 3:12 pm

AFIK Its just a modern improvement on road cars. Much has been said about current oils being made with roller cams in mind to the detriment of flat tappet cams, so I would refute the suggestion that roller cams are only suitable for racing?

Longevity of many current 'warm/hotter' cams would be improved by having a roller contact mechanism, and evenstill allow implementation of slightly more aggressive profiles I would have thought. - Without resorting to ridiculous levels of acceleration in the valve train that you would use in full race engines?

crayefish · Post by **crayefish** » Wed Sep 23, 2009 4:19 pm

chodjinn wrote:Flat tappet cams can only go so far in terms of spring pressures that they can cope with. Roller cams are used for full-on race engines.

Roller cams and tappets allow much higher spring rates to be used, therefore allowing more lift etc on the valves, which is needed in race engines to maximise the power.

There isn't much point in having roller cams/tappets in a road engine is there? It would be a pig to drive.

I would have thought the order is something like this;

Hydraulic - Road/Mild Race
Solid - Fast Road/Race/mild Drag
Roller - Full race/drag

The advantage of a roller cam is that much steeper ramp angles can be used, and hence the need also for higher spring pressures.

This means you can have the duration of a fast road cam, but with the valve open at higher lifts for longer which means greater potential for cylinder filling.

Mark · Post by **Mark** » Wed Sep 23, 2009 8:17 pm

My 5 litre Ford V8 came stock with a hydraulic roller cam and it only makes 150 bhp

Mark

topcatcustom · Post by **topcatcustom** » Wed Sep 23, 2009 8:26 pm

Mark wrote:My 5 litre Ford V8 came stock with a hydraulic roller cam and it only makes 150 bhp

Mark

Did they forget to put the pushrods in or something Mark?!!!

HairbearTE · Post by **HairbearTE** » Wed Sep 23, 2009 9:03 pm

Another point to consider is that the base circle of the rover cam is really too small to effectively host a roller lobe. That means custom cam, cam journals, bearings etc. Like olly says, if it could be done for $500 everyone would have one..

crayefish · Post by **crayefish** » Wed Sep 23, 2009 9:04 pm

Ah... I see the point... once you get into line boring bigger journals etc it would start to get expensive.

ppyvabw · Post by **ppyvabw** » Wed Sep 23, 2009 11:18 pm

spend wrote:You can have hydraulic roller cams as well. I don't see this argument about massive spring pressures, surely that is confusing racing cams with road cams? Just seems to me like it would be a lot easier for springs to keep a roller on the cam than a spinning flat tappet? Start adding aggressive cam profiles, bigger heavier valves, 1000s more rpms and you change the goalposts dramatically either roller or flat;)

Why is spring pressure more of an issue with roller cams than flat tappet cams? Ideally you still want to keep the tappet on the cam, whether it's a roller or a flat one. I don't think spring pressure should be an issue.

The issue with roller cams is the cam profile itself and the ramp angle as I understand it, why would you need a higher spring pressure?