I've heard alot awout this 'lumpy cam' can someone tell me what it is/does?
lumpy cam?
Started by
_tyre fryer_
, Jan 13 2007 01:05 AM
20 replies to this topic
#2
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Posted 13 January 2007 - 01:14 AM
prob differing ops on it but in general,
A;you know what a stock car sounds like at idle, well a lumpy cam sounds like a miss or a race car idling.
B; a race cam (one thats usually too big for a stock motor) or a big cam for a worked motor is usually refered to as lumpy.
Edit; what it does, sounds tuff and goes hard.
A;you know what a stock car sounds like at idle, well a lumpy cam sounds like a miss or a race car idling.
B; a race cam (one thats usually too big for a stock motor) or a big cam for a worked motor is usually refered to as lumpy.
Edit; what it does, sounds tuff and goes hard.
Edited by ALX76, 13 January 2007 - 01:16 AM.
#3
_tyre fryer_
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Posted 13 January 2007 - 02:17 AM
ok.. thats the first thing for the v8. lol. whats a cam wrth. a 'lumpy' one? for a 304 injected from a vt?
#4
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Posted 13 January 2007 - 03:34 AM
slow down mate, best you pick a cam that suites your motor combo/driving style.
have a read of this first.
http://www.cranecams.../?show=faq&id=2
have a read of this first.
http://www.cranecams.../?show=faq&id=2
#5
_Yella SLuR_
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Posted 13 January 2007 - 05:03 AM
100% agree with ^. Cam is the brains of the engine, get that wrong, and get the whole drive of your car wrong. Do your research first. Most of the cam manufacturer's have a cam questionaire, that will select a cam for you. They used to be online and give you an instant answer, but they seem to not be online anymore. Have a look around and do your homework.
The lumpiness of the cam is usually described by the manufacturer's as the lope at idle. A rough lope at idle is usually a very lumpy cam as they are operating way outside their optimum operating range at idle, i.e. 5,000 - 9,000 RPM operating range (way to big for normal road use).
With all this talk of V8's, aren't you only 15 or something? So you'd be building a car that you couldn't drive anyways (in NSW anyways).
The lumpiness of the cam is usually described by the manufacturer's as the lope at idle. A rough lope at idle is usually a very lumpy cam as they are operating way outside their optimum operating range at idle, i.e. 5,000 - 9,000 RPM operating range (way to big for normal road use).
With all this talk of V8's, aren't you only 15 or something? So you'd be building a car that you couldn't drive anyways (in NSW anyways).
Edited by Yella SLuR, 13 January 2007 - 05:08 AM.
#6
_LXChev366_
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Posted 13 January 2007 - 08:37 AM
This is him with his car...
http://www.gmh-toran...opic=12874&st=0
But this is good... like I said elsewhere... ask Q's and learn..
JUST fitting a so called LUMPY cam isn't enough.... you have to have all the other mods done to the engine to MATCH the lumpy Cam... Mild cam maybe but not a big "Lumpy" one.
Yep my race engine has a lumpy cam... just ask Yella^, but mind you, it has all the other stuff to go with it...including alloy heads, Single plain manifold, Barry Grant 750 Carb, Roller rockers, $2000 exhaust, MSD ignition system etc.....
http://www.gmh-toran...opic=12874&st=0
But this is good... like I said elsewhere... ask Q's and learn..
JUST fitting a so called LUMPY cam isn't enough.... you have to have all the other mods done to the engine to MATCH the lumpy Cam... Mild cam maybe but not a big "Lumpy" one.
Yep my race engine has a lumpy cam... just ask Yella^, but mind you, it has all the other stuff to go with it...including alloy heads, Single plain manifold, Barry Grant 750 Carb, Roller rockers, $2000 exhaust, MSD ignition system etc.....
#7
_rorym_
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Posted 13 January 2007 - 10:23 AM
Time to start reading books Fryer...get some from the newsagents on basic engine builds by Hotrod Mag or similiar...usually chev ones but it explains the basic principles of how an engine works and what does what...the learning has begun! 
R
R
#8
_Yella SLuR_
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Posted 13 January 2007 - 11:35 AM
Yup, car jumps around on the front suspension at idle. That's prolly a bit lumpier than what you are after.Yep my race engine has a lumpy cam... just ask Yella.....
Pete, are you running solid cam or roller cam?
Edited by Yella SLuR, 13 January 2007 - 11:37 AM.
#9
_tyre fryer_
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Posted 13 January 2007 - 12:08 PM
I'm 16 and wont be building this car for atleast 12 months.. just getting the info now.
there's no restrictions in SA as to engine capacity. I do intend to do all the other mods. V8 stock is enough power for me. I just want the pure sound atm.
there's no restrictions in SA as to engine capacity. I do intend to do all the other mods. V8 stock is enough power for me. I just want the pure sound atm.
#10
_[BOTTLEDUP]_
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Posted 13 January 2007 - 12:59 PM
Have you already got a VT 5.0 litre? If not perhaps search for an earlier engine, otherwise you will need to run the EFI and all the relevant emissions gear for the car to pass registration.
The VT engines ran a hydraulic roller cam which in itself is a good thing, however it is expensive to replace.
The VT engines ran a hydraulic roller cam which in itself is a good thing, however it is expensive to replace.
#11
_LXChev366_
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Posted 13 January 2007 - 02:56 PM
Crane Solid Cam and Speed Pro Solid Lifters.Pete, are you running solid cam or roller cam
#12
_Yella SLuR_
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Posted 13 January 2007 - 03:01 PM
EFI already exceeds the requirements of 27A, therefore it is better on emissions than the red motors. For that reason you don't need to fit cat converters for an EFI upgrade to an older car. Computers ensure a cleaner burn on every single firing of the cylinder.Have you already got a VT 5.0 litre? If not perhaps search for an earlier engine, otherwise you will need to run the EFI and all the relevant emissions gear for the car to pass registration.
#13
_[BOTTLEDUP]_
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Posted 13 January 2007 - 04:32 PM
So Yella are you saying any EFI car passes ADR27A?
I don't think so some how.
I don't think so some how.
#14
FastEHHolden
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Posted 13 January 2007 - 04:48 PM
they are all lumpy 
#15
_tyre fryer_
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Posted 13 January 2007 - 06:35 PM
ok.. so you say an earlier than VT engine? I want one with EFI because it's plenty more efficient as I understand. I don't have any ATM I could just rebuild an old 308 and drop her in if there's not that much difference between the carby and EFI ones.
#16
_Yella SLuR_
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Posted 13 January 2007 - 08:44 PM
It exceeds it. That's what we found out with Herne's EFI conversion. You get a more complete burn with combined EFI and computer engine management system.,Jan 13 2007, 05:32 PM] So Yella are you saying any EFI car passes ADR27A?
I don't think so some how.
Edited by Yella SLuR, 13 January 2007 - 08:45 PM.
#17
_devilsadvocate_
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Posted 13 January 2007 - 09:10 PM
Has the ^ been approved by the registration authorities, it may well produce lower HC and CO emissions but was the setup tested for NOx emissions, not typically measured on most exhaust analysers. part of adr27a is reducing NOx emissions.
The efi motor is typically designed to meet NOx emissions through one stage in the catalytic convertor and not having this may make its NOx emissions not meet the requirements of adr27a. It maybe that the authorities have accepted a trade off, that HC and CO emissions are lower than the 1976 car would have produced in exchange for higher NOx levels.
The efi motor is typically designed to meet NOx emissions through one stage in the catalytic convertor and not having this may make its NOx emissions not meet the requirements of adr27a. It maybe that the authorities have accepted a trade off, that HC and CO emissions are lower than the 1976 car would have produced in exchange for higher NOx levels.
#18
_Yella SLuR_
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Posted 13 January 2007 - 09:13 PM
^ yeah dunno. I was surprised as well, but Herne checked and double checked it.
#19
_chevy_253_torana_
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Posted 13 January 2007 - 09:14 PM
also with choosing engine cams just becarefull
like my 253 im doing up i chose to get a medium rated 308 cam (cant rememeber the specs now!)
for a 253 this cam would be hot and as it says on the ad in the catalogue
WARNING NOT RECOMENDED FOR 253 WITH AUTO
nothing a high stall torque converter cant fix
plus my mate who did a 253 up a couple years back showed me this was the cam to get they whacked it in a vb commodore and the thing was just wnating to get up and go the whole time
loved the revs and best of all the power she was a making
if your upgrading the cam lifters is mandatory (at least in this household)
also check the pushrods to see how straight they are
like my 253 im doing up i chose to get a medium rated 308 cam (cant rememeber the specs now!)
for a 253 this cam would be hot and as it says on the ad in the catalogue
WARNING NOT RECOMENDED FOR 253 WITH AUTO
nothing a high stall torque converter cant fix
plus my mate who did a 253 up a couple years back showed me this was the cam to get they whacked it in a vb commodore and the thing was just wnating to get up and go the whole time
loved the revs and best of all the power she was a making
if your upgrading the cam lifters is mandatory (at least in this household)
also check the pushrods to see how straight they are
#20
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Posted 14 January 2007 - 02:50 AM
yeah thats because the top end is on a pre 89 block, try it with a post 89 block and see how far you get with the RTA.^ yeah dunno. I was surprised as well, but Herne checked and double checked it.
#21
_[BOTTLEDUP]_
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Posted 14 January 2007 - 11:41 AM
There is limited physical differences between the early and late 308/304 V8s, most parts are interchangeable.ok.. so you say an earlier than VT engine? I want one with EFI because it's plenty more efficient as I understand. I don't have any ATM I could just rebuild an old 308 and drop her in if there's not that much difference between the carby and EFI ones.
As far as licensing is concerned, fitting the later model heads and efi to an early block means you won't need all the pollution gear from the VT, as Yella has touched on.
So finding an equiv year 308 (red or blue, from an Early commo, Kingswood/WB etc) and working from there would be a good starting point.
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