My car is a triumph stag rebuilt ready for the implant of a Rover 3.5 for the open road. Looking to improve the standard power in my RR 3.5 with a CR 9.35, been offered a new "hot cam" with Rhodes lifters from a mate, cannot seem to find any real info online that I as a layman can understand, basically Ive been offered it for next to nothing, is it worth it or are there more better cam/lifters out there for little money?
I'm planning on a few other engine mods Megga squirt etc. 4 branch manifolds etc. The block has been honed, has Hepolight rings, lots of ARP bolts n stuff. Dont want more than say 200bhp as the poor old girl wont be able to handle it without major upgrades, but is 200BHP a posibility with that cam?
Mick
Camshaft
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CastleMGBV8
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Mick,
To get 200+ BHp on a road engine is fairly straightforward but does cost a bit of money.
Firstly if an engine is restricted in flow capacity by the heads as the Rover is adding a hot cam will yield very litttle at the top end and lose you more at the low RPM range and probably make the car slower overall.
So as Chris said the first place to start is a pair of Stage 1 heads which have had the seats and throat areas opened up and blended into the bowls, and with the guides bulleted in the port area will yield an additional 30+ BHP even with the standard valves and cam, add a fast road cam and you will get to approx 210 BHP which will give good performance and drivability.
Forget the Rhoads lifters, they are extremely noisy and are for use with very hot cams to make the engine more drivable on the road.
If the cam you have been offered is unused let us know what it is and we can tell you if it is suitable for your intended use. Cams are relatively cheap at around £125.00 and must be used with new lifters and a pair of heads will cost approx £5-600.00 because it is labour intensive work.
Kevin.
To get 200+ BHp on a road engine is fairly straightforward but does cost a bit of money.
Firstly if an engine is restricted in flow capacity by the heads as the Rover is adding a hot cam will yield very litttle at the top end and lose you more at the low RPM range and probably make the car slower overall.
So as Chris said the first place to start is a pair of Stage 1 heads which have had the seats and throat areas opened up and blended into the bowls, and with the guides bulleted in the port area will yield an additional 30+ BHP even with the standard valves and cam, add a fast road cam and you will get to approx 210 BHP which will give good performance and drivability.
Forget the Rhoads lifters, they are extremely noisy and are for use with very hot cams to make the engine more drivable on the road.
If the cam you have been offered is unused let us know what it is and we can tell you if it is suitable for your intended use. Cams are relatively cheap at around £125.00 and must be used with new lifters and a pair of heads will cost approx £5-600.00 because it is labour intensive work.
Kevin.
Hi
An idea of the ppec of the cam would be a good idea, Roads lifters "soften" a cam below about 3000 to 3500 rpm, handy if your cam is lumpy with loads of overlap and will let the engine make peek power at about 5800 to 6600 revs and rev beyond that. If the cam produces peak power at 4800 to 5200 revs then you will not gain alot using them and will clobber peak torque (which on a cam of that spec would be arround 3000 to 3200) just to gain a smoother idle. you really need about 225 degrees of duration at .05" to make use or roads lifters (with an LSA around 108 deg) and to go with that cam a set of well ported stage 2 or 3 heads, otherwise the heads will strangle the engine just as it starts to make power on the cam.
Best regards
Mike
An idea of the ppec of the cam would be a good idea, Roads lifters "soften" a cam below about 3000 to 3500 rpm, handy if your cam is lumpy with loads of overlap and will let the engine make peek power at about 5800 to 6600 revs and rev beyond that. If the cam produces peak power at 4800 to 5200 revs then you will not gain alot using them and will clobber peak torque (which on a cam of that spec would be arround 3000 to 3200) just to gain a smoother idle. you really need about 225 degrees of duration at .05" to make use or roads lifters (with an LSA around 108 deg) and to go with that cam a set of well ported stage 2 or 3 heads, otherwise the heads will strangle the engine just as it starts to make power on the cam.
Best regards
Mike
poppet valves rule!
The huricane can is pretty short duration even on a 3.5L, I would think the Roads lifter would not show any gain and just rattle.
Have a look at the real steel website at the cams on there, SD1 heads in standard form will start to seriously limit power at about 5400 revs on a 3.5 so unless you are going to have the heads ported you want to have a cam that makes peak power at about 5000. no point in having lifters that restrict duration and valve lift until 3500 in that case as it will give you a 1900 rev power band.
Mike
Have a look at the real steel website at the cams on there, SD1 heads in standard form will start to seriously limit power at about 5400 revs on a 3.5 so unless you are going to have the heads ported you want to have a cam that makes peak power at about 5000. no point in having lifters that restrict duration and valve lift until 3500 in that case as it will give you a 1900 rev power band.
Mike
poppet valves rule!
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CastleMGBV8
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Mick,
Agree with Mike, the hurricane cam is fairly mild but will work fine in an engine for road use at your desired power output
The heads will definitely need some work and you could use standard lifters if you dont want rev much over 5200 RPM which you wouldn't need to anyway.
The Rhoads lifters will not be of any use with that cam and you will think the engines clapped if you use them. Do not understand what you mean by shimmed Rhoads Lifters?
You mention comtec gaskets, do you mean composite gaskets? as the heads should be machined 30 thou. off the faces or you will lose compression and have a problem with the lifter preload.
Also Manual or Auto gearbox?
Kevin.
Agree with Mike, the hurricane cam is fairly mild but will work fine in an engine for road use at your desired power output
The heads will definitely need some work and you could use standard lifters if you dont want rev much over 5200 RPM which you wouldn't need to anyway.
The Rhoads lifters will not be of any use with that cam and you will think the engines clapped if you use them. Do not understand what you mean by shimmed Rhoads Lifters?
You mention comtec gaskets, do you mean composite gaskets? as the heads should be machined 30 thou. off the faces or you will lose compression and have a problem with the lifter preload.
Also Manual or Auto gearbox?
Kevin.
Well I think I'm starting to get me head around this power thing after the good advice and a bit of research.
So: The viper cam gives a small increase in performance without the need for head rework, due to the heads max valve lift of .44", of which the cam gives .43". And as far as I know the heads havent been skimmed. So as I cant afford any head rework, think I might use the Viper cam as its supposidly gives 20bhp increase.
Seems the rhoads lifters are a no go as they bleed below 3500rpm. reducing the power range. So should I use solid ones or hydraulic lifters?
Im fitting P38 exhaust manifolds so hopefully that will give a boost to the output. The standard SD1 power is about 150-155 so with the megasquirt hope for 190 to 200bhp.
Thanks for the info and advice. Any more is always appreciated.
Mick
So: The viper cam gives a small increase in performance without the need for head rework, due to the heads max valve lift of .44", of which the cam gives .43". And as far as I know the heads havent been skimmed. So as I cant afford any head rework, think I might use the Viper cam as its supposidly gives 20bhp increase.
Seems the rhoads lifters are a no go as they bleed below 3500rpm. reducing the power range. So should I use solid ones or hydraulic lifters?
Im fitting P38 exhaust manifolds so hopefully that will give a boost to the output. The standard SD1 power is about 150-155 so with the megasquirt hope for 190 to 200bhp.
Thanks for the info and advice. Any more is always appreciated.
Mick
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CastleMGBV8
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- Joined: Sat Aug 18, 2007 5:09 pm
- Location: Sidcup, Kent, UK
Mick,
The Viper Hurrican cam is a hydraulic cam and you must use hydralic lifters.
The cam will help a bit with performance and perhaps make the engine a bit more freer revving, but you will not get the full benefit until you have the head work done. With engines in simple terms it's all about how much you can get through a hole and that applies to the exhaust system as well.
That can come later, you can pick up a pair of later 4.0 or 4.6 heads with the smaller 28cc combustion chambers which flow marginally better due to having waisted stem valves and can usually be found for less than a £100 a pair and then as money allows you can have them stage 1 modded or possiby learn how to do them yourself if handy with tools.
You could get a local machine shop to recut the seats to valve seat size and get them to blend the bowls and grind down the bottom of the valve guides which is fairly straighforward machine work.
If you go to a precision engineering shop as opposed to an engine tuner the machine work will be a lot cheaper, you migh get away with £200.00 for the basic work. I have a very good one local to me in sidcup which is handy, where are you based?
Ports should never be polished which is a popular misconception.
Kevin.
The Viper Hurrican cam is a hydraulic cam and you must use hydralic lifters.
The cam will help a bit with performance and perhaps make the engine a bit more freer revving, but you will not get the full benefit until you have the head work done. With engines in simple terms it's all about how much you can get through a hole and that applies to the exhaust system as well.
That can come later, you can pick up a pair of later 4.0 or 4.6 heads with the smaller 28cc combustion chambers which flow marginally better due to having waisted stem valves and can usually be found for less than a £100 a pair and then as money allows you can have them stage 1 modded or possiby learn how to do them yourself if handy with tools.
You could get a local machine shop to recut the seats to valve seat size and get them to blend the bowls and grind down the bottom of the valve guides which is fairly straighforward machine work.
If you go to a precision engineering shop as opposed to an engine tuner the machine work will be a lot cheaper, you migh get away with £200.00 for the basic work. I have a very good one local to me in sidcup which is handy, where are you based?
Ports should never be polished which is a popular misconception.
Kevin.
Unfortunately I'm in inverness, there is a precision engineering place nearby but as with most things up here they are rediculously expensive. I really need to lower the front of the car next as the RV8 is about 50kg lighter than the TV8. So an upgrade the car brake and suspension poly bushes etc should be next, but will definately look into replacement 4.0 4.6 heads and possibly getting the work you suggest done. Thats great info thanks.
mick
mick
placed near you http://www.bhengineering.co.uk/
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CastleMGBV8
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Mick,
If you do a search in your area for Precision engineers you will find that most of them are capable of doing engine work and are also prbabably the people that the engine tuners/modifiers are farming out work to and charging a high mark up for the work.
Most engine tuners do not do this work in house.
Kevin.
If you do a search in your area for Precision engineers you will find that most of them are capable of doing engine work and are also prbabably the people that the engine tuners/modifiers are farming out work to and charging a high mark up for the work.
Most engine tuners do not do this work in house.
Kevin.
