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camshafts
- Thread starter Bigman
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I think all of the camshafts are interchangeable. The rockers on top of the head are not. To get the best performance you should also change to a early style distributor or get a new 45D that has the early advance curve. None of this will work without changing from stock carb to either a weber or twin SU’s.
Can anyone tell me what is the difference in rocker from early to late model? Will roller rockers be the answer. Is it possible to install different spring in the late model distributor to get a early advance curve. Has anyone tried a offset key in the cam to gain performance?
Thanks
Bigman
Thanks
Bigman
Bret
Yoda
Offline
[ QUOTE ]
Can anyone tell me what is the difference in rocker from early to late model? Will roller rockers be the answer. Is it possible to install different spring in the late model distributor to get a early advance curve. Has anyone tried a offset key in the cam to gain performance?
Thanks
Bigman
[/ QUOTE ]
Moss and Victoria British both sell Roller Rockers for the MGB. Be careful as the pedestals are different for the early years & the later years like yours. So make sure know what you have before you order. But I would hold on this as they are pricy and shouldn’t be really be considered unless you are building a motor that you plan on exceeding 6000RPMs. But if you seriously plan on building up the motor for that realm of the power band, you’ll certainly need to up rate the rest of you’re valve train accordingly (Springs etc).
Here is a great reference book you should look for if this is your plan: How To Power Tune MGB 4-Cylinder Engines (For Road & Track) By Peter Burgess. Amazon sells it.
/ubbthreads/images/graemlins/thumbsup.gif
Anyway - regarding the distributor: An 1980 MGB like yours probably came “stock” with 45DM4 (CEI) Dizzies. So yours shouldn’t have springs unless you have one from an earlier model year or one of the aftermarket flavors (duel points etc) offered up by folks like MSD. But I’d look to see exactly what you got, before you spend any money.
I was unsure if my Distributor was up to par – but the price of blindly replacing components like the amplifier or vacuum units - seemed a bit pricy and daunting. That’s when I opted to upgrade the tired old CEI Dizzy with one of those “hall effect” Ignitor EFI systems offered by PerTronix, along with one of their Flamethrower coils. As well as some nice (Bosch) plugs, wires, cap & rotor. The results where immediate and quite telling.
Good luck.
/ubbthreads/images/graemlins/cheers.gif
Can anyone tell me what is the difference in rocker from early to late model? Will roller rockers be the answer. Is it possible to install different spring in the late model distributor to get a early advance curve. Has anyone tried a offset key in the cam to gain performance?
Thanks
Bigman
[/ QUOTE ]
Moss and Victoria British both sell Roller Rockers for the MGB. Be careful as the pedestals are different for the early years & the later years like yours. So make sure know what you have before you order. But I would hold on this as they are pricy and shouldn’t be really be considered unless you are building a motor that you plan on exceeding 6000RPMs. But if you seriously plan on building up the motor for that realm of the power band, you’ll certainly need to up rate the rest of you’re valve train accordingly (Springs etc).
Here is a great reference book you should look for if this is your plan: How To Power Tune MGB 4-Cylinder Engines (For Road & Track) By Peter Burgess. Amazon sells it.
/ubbthreads/images/graemlins/thumbsup.gif
Anyway - regarding the distributor: An 1980 MGB like yours probably came “stock” with 45DM4 (CEI) Dizzies. So yours shouldn’t have springs unless you have one from an earlier model year or one of the aftermarket flavors (duel points etc) offered up by folks like MSD. But I’d look to see exactly what you got, before you spend any money.
I was unsure if my Distributor was up to par – but the price of blindly replacing components like the amplifier or vacuum units - seemed a bit pricy and daunting. That’s when I opted to upgrade the tired old CEI Dizzy with one of those “hall effect” Ignitor EFI systems offered by PerTronix, along with one of their Flamethrower coils. As well as some nice (Bosch) plugs, wires, cap & rotor. The results where immediate and quite telling.
Good luck.
/ubbthreads/images/graemlins/cheers.gif
My distributor in my 1980 MGB has spring for the centrifugal advance. I also have a Crane electronic ignition installed with a crane coil. Will changing the springs inside the distributor help the performance?
I have a weber carb and headers on my engine now. So will changing the cam to the early cam help the performance?
I have a weber carb and headers on my engine now. So will changing the cam to the early cam help the performance?
Bret
Yoda
Offline
[ QUOTE ]
My distributor in my 1980 MGB has spring for the centrifugal advance. I also have a Crane electronic ignition installed with a crane coil. Will changing the springs inside the distributor help the performance?
I have a weber carb and headers on my engine now. So will changing the cam to the early cam help the performance?
[/ QUOTE ]
Hmmm? Well it sounds like the previous owner has already added a few aftermarket goodies. So yes if the Distributor has springs you could possibility see some gains by changing the springs but this could be a double edged sword. You could see some improvements but the only way to know is to find out what kind of dizzy you have and talk to the manufacture. It turns out the manufacture isn’t around anymore you’ll be stuck doing some experimentation with different springs.
As for the Camshaft question; Assuming we are talking about a stock camshaft - as Jim indicated, all camshafts from 65-80 are indeed interchangeable. But if they are interchangeable I wouldn’t expect any power gains. You’d need to up grade to a fast street or road cam to see anything significant.
Also if are you thinking of taking the camshaft out of an older engine to install in your 80 engine? Please reconsider. I’d caution against using the internals out of another engine unless you know that engine and are comfortable with its history. Otherwise you might consider having a machine shop check them out first to see if it needs to be reworked. While this might seem to be the cheaper way to go – because of all of the “unknowns” that come with used components, I’d opt for a new camshaft altogether and have peace of mind.
As many here can attest - I am not a big fan of replacing old warn out parts with other old warn out parts. This sentiment of mine goes double for internal engine components. Think about it – your cam may just be old and need replacing anyway. A stock new came should see a significant improvement over an old tired one. Or as I said before - consider upgrading to a fast street performance cam. With the modifications you already have – I think you’ll be pleasantly surprised.
Good luck!
/ubbthreads/images/graemlins/cheers.gif
My distributor in my 1980 MGB has spring for the centrifugal advance. I also have a Crane electronic ignition installed with a crane coil. Will changing the springs inside the distributor help the performance?
I have a weber carb and headers on my engine now. So will changing the cam to the early cam help the performance?
[/ QUOTE ]
Hmmm? Well it sounds like the previous owner has already added a few aftermarket goodies. So yes if the Distributor has springs you could possibility see some gains by changing the springs but this could be a double edged sword. You could see some improvements but the only way to know is to find out what kind of dizzy you have and talk to the manufacture. It turns out the manufacture isn’t around anymore you’ll be stuck doing some experimentation with different springs.
As for the Camshaft question; Assuming we are talking about a stock camshaft - as Jim indicated, all camshafts from 65-80 are indeed interchangeable. But if they are interchangeable I wouldn’t expect any power gains. You’d need to up grade to a fast street or road cam to see anything significant.
Also if are you thinking of taking the camshaft out of an older engine to install in your 80 engine? Please reconsider. I’d caution against using the internals out of another engine unless you know that engine and are comfortable with its history. Otherwise you might consider having a machine shop check them out first to see if it needs to be reworked. While this might seem to be the cheaper way to go – because of all of the “unknowns” that come with used components, I’d opt for a new camshaft altogether and have peace of mind.
As many here can attest - I am not a big fan of replacing old warn out parts with other old warn out parts. This sentiment of mine goes double for internal engine components. Think about it – your cam may just be old and need replacing anyway. A stock new came should see a significant improvement over an old tired one. Or as I said before - consider upgrading to a fast street performance cam. With the modifications you already have – I think you’ll be pleasantly surprised.
Good luck!
/ubbthreads/images/graemlins/cheers.gif
If you want driveability, and power this is what i have done,
Kent 719SP Scatter pattern cam kit with new springs and retainers,
Rimflow anti reversion Ststeel valves,
Rollmaster duplex vernia timing chain and gear kit,
18V late model Cyl head ported and CC'd
All MGB gear and all installed into a 1600 MGA block...no problems, the only thing you must watch is as my valves were so large and the lift was increased i needed to flycut the block to prevent them hitting the bores, as for that i lightend the flywheel, across the back and removed material outside of the friction area towards the ring gear. i run a 45dcoe side draft webber, and Lcb extractors and side exit exhaust, it runs up to 7000r pm on occasions and is very strong.......suprised my friend with a stripped mga race car. Very tractable and not tempremental, if you can afford it have the vehicle dynotuned to setup the ignition and carb as this makes a huge difference.
And goodluck, any questions jjust drop us a line
Cheers
Skip
Kent 719SP Scatter pattern cam kit with new springs and retainers,
Rimflow anti reversion Ststeel valves,
Rollmaster duplex vernia timing chain and gear kit,
18V late model Cyl head ported and CC'd
All MGB gear and all installed into a 1600 MGA block...no problems, the only thing you must watch is as my valves were so large and the lift was increased i needed to flycut the block to prevent them hitting the bores, as for that i lightend the flywheel, across the back and removed material outside of the friction area towards the ring gear. i run a 45dcoe side draft webber, and Lcb extractors and side exit exhaust, it runs up to 7000r pm on occasions and is very strong.......suprised my friend with a stripped mga race car. Very tractable and not tempremental, if you can afford it have the vehicle dynotuned to setup the ignition and carb as this makes a huge difference.
And goodluck, any questions jjust drop us a line
Cheers
Skip