MGB & GT Forum
Power tune my B, winter project .. ?
Posted by wicklowwanderer
wicklowwanderer
David Steverson
Marietta, GA, USA
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Oct 19, 2014 04:43 PM
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Thinking about a winter project and based on available money, wondered about adding some power to my B. I see the Burgess book "How to Power Tune MGB 4-Cylinder Engines", thinking that might be a start. My engine is has 500 miles on a bone stock complete rebuild, 30 over pistons, 25D distributor (built by Advanced), Moss stainless exhaust with factory header. Should I buy the book, where might I start with the engine?
Thanks, David
Visit my artists website at www.WicklowWanderer.com
Thanks, David
Visit my artists website at www.WicklowWanderer.com
reedrickborn
Reed Rickborn
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Oct 19, 2014 10:03 PM
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David.
I have the book and it has some good tips. But as the old saying goes speed cost money. I don't know if you will find just as much info on the forum. Peter Burgess seem to lean toward head work to improve performance. I had my head ported and polished a few years back and it seem to have a smoother idle and better performance. For me it's more about reliabity, braking and handling. If I wanted to go real fast real quick I would probably buy a new MX5.
I have the book and it has some good tips. But as the old saying goes speed cost money. I don't know if you will find just as much info on the forum. Peter Burgess seem to lean toward head work to improve performance. I had my head ported and polished a few years back and it seem to have a smoother idle and better performance. For me it's more about reliabity, braking and handling. If I wanted to go real fast real quick I would probably buy a new MX5.
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Oct 19, 2014 10:42 PM
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In general, the head is a good start but a perhaps more productive way would be cam, compression, then head.
The first two mean undoing some of what you just spent a bunch on. Changing the cam (and lifters! Buy ONLY the hardened lifters, get cam and lifters from APT!) means engine out (dunno how to properly install cam with engine in the car. Some may and that's good.). Better price than the same from Moss. With cam and compression then head will be worth more. Distributor will need recurving then as well, and a dozen other things. Will not be as cheap as you might imagine.
Or consider the Moss supercharger. The cost would be comparable, I suspect. $4G is 4G no matter where it's spent.
One important question which is crucial.
How do you drive? If your driving is wide open throttle, often above posted limits, and charging hard thru corners and running 4-5,000 rpm most all the time (i.e. Corvette envy<G> you have one set of conditions.
If you are more of a cruiser and shift at 4K and drive at 2-3.5, but just want more punch at 2500, then that's a little different. And a different set of pieces will deliver that.
The MGB is and always was a low-powered thing, I don't think any car sold in the US today has as low power as the B had, even in the inflated British rating of the time. It is not a fast car. Wasn't 50 years ago, even less so today. You wanna chase Hondas, get a Honda. You wanna drive a machine instead of an appliance, get an MGB. And enjoy the difference.
Me? had I the $ and knowing my car, I'd go for the Moss Supercharger. Or a V6 conversion (which might be in the same price range) But the dollars are so much beyond what my Social Security spits out that it is nonsense for me to think of it.
1973 Pale Primrose Roadster. A nice 10-footer!
SUs, Datsun 5-speed
The first two mean undoing some of what you just spent a bunch on. Changing the cam (and lifters! Buy ONLY the hardened lifters, get cam and lifters from APT!) means engine out (dunno how to properly install cam with engine in the car. Some may and that's good.). Better price than the same from Moss. With cam and compression then head will be worth more. Distributor will need recurving then as well, and a dozen other things. Will not be as cheap as you might imagine.
Or consider the Moss supercharger. The cost would be comparable, I suspect. $4G is 4G no matter where it's spent.
One important question which is crucial.
How do you drive? If your driving is wide open throttle, often above posted limits, and charging hard thru corners and running 4-5,000 rpm most all the time (i.e. Corvette envy<G> you have one set of conditions.
If you are more of a cruiser and shift at 4K and drive at 2-3.5, but just want more punch at 2500, then that's a little different. And a different set of pieces will deliver that.
The MGB is and always was a low-powered thing, I don't think any car sold in the US today has as low power as the B had, even in the inflated British rating of the time. It is not a fast car. Wasn't 50 years ago, even less so today. You wanna chase Hondas, get a Honda. You wanna drive a machine instead of an appliance, get an MGB. And enjoy the difference.
Me? had I the $ and knowing my car, I'd go for the Moss Supercharger. Or a V6 conversion (which might be in the same price range) But the dollars are so much beyond what my Social Security spits out that it is nonsense for me to think of it.
1973 Pale Primrose Roadster. A nice 10-footer!
SUs, Datsun 5-speed
ohlord
Rob C
A tiny Island off the coast of Washington State, N.W., USA
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Oct 19, 2014 10:51 PM
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500 miles on a new engine unless you want to tear it apart ,raise compression.install a mild street performance cam,etc. justleave it alone and take a certified high performance driving school course.
When the engine is due for a rebuild someday far in the future then build it to the level of your skills.
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When the engine is due for a rebuild someday far in the future then build it to the level of your skills.
LNDRVR4X4.COM
Home of Project "INCARN8'
1957 Series 1 Land Rover electric VEHICLE CONVERSION
FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED
RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972
Oct 20, 2014 06:34 AM
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From my point of view it's a no brainer David. 500 miles on a 30 over bone stock rebuild? Why fix it if it ain broke my friend? The Moss or Hi-Flow Supercharger is the answer hands down for a few scheckles more. I guran-gud-damn-tee you it will wind up close to that in a Burgess guided power up rebuild- all in with all the: " well, I'm here now so why not Carillo rods, windage tray, rollers, P-285, etc." With the SC, you don't have to pull the engine, and only need Jeff to recurve that D25 to 28* all in around 3000 rpms. I'd suggest the Brit Vac Units diaphram for the 72-75 HIF dizzy for manifold, not port vacuum for idle advance around 19*.
Finally, when the day is done for a power build, you will not be much over 100RWHP ( if that) and have a tweaky engine. Out of the box, with a Burgess head 8 years ago, I logged 123RWHP with the Moss SC. Nowadays guys like Dan, Ray, and Adrian are well above that. Last bennie is you don't even know the SC is there till you grab a hand full, and then that silly smile starts to happen. Cheers, Vem
Finally, when the day is done for a power build, you will not be much over 100RWHP ( if that) and have a tweaky engine. Out of the box, with a Burgess head 8 years ago, I logged 123RWHP with the Moss SC. Nowadays guys like Dan, Ray, and Adrian are well above that. Last bennie is you don't even know the SC is there till you grab a hand full, and then that silly smile starts to happen. Cheers, Vem
wicklowwanderer
David Steverson
Marietta, GA, USA
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Topic Creator (OP)
Oct 20, 2014 07:13 AM
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Thanks for the comments! What got this started was watching an episode of 'For the love of cars;, the one where they had an Escort Mexico. I looked up the specs and found that model was about 130 pounds lighter than my GT, had a few HPs, but it's 0-60 time was about 3 seconds faster. So I started thinking about this for a winter project. Having read the above comments and realizing my extra dosh would be minimal, I'll find something else.
David
Visit my artists website at www.WicklowWanderer.com
David
Visit my artists website at www.WicklowWanderer.com
mgbanthony
Anthony Henderson
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Oct 20, 2014 07:40 AM
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Bs respond well to a mild over bore such as you have. It seems to increase their low/mid-range power very nicely.
Depending on budget the next step is to have the cylinder head worked over by one who knows MGB heads, and there are several who post here regularly. Also have the carbs and intake matched to the head.
2A is to have Jeff Schlemmer overhaul your 25D and match it to your engine specs, and you have done that.
Beyond that, short of blueprinting the bottom end, lightening and balancing rotating components....which I wouldn't do on a fresh built engine.....unless money is no object...
Next step.supercharger.
You need more than 500 miles to reap the benefits of what you have.
Depending on budget the next step is to have the cylinder head worked over by one who knows MGB heads, and there are several who post here regularly. Also have the carbs and intake matched to the head.
2A is to have Jeff Schlemmer overhaul your 25D and match it to your engine specs, and you have done that.
Beyond that, short of blueprinting the bottom end, lightening and balancing rotating components....which I wouldn't do on a fresh built engine.....unless money is no object...
Next step.supercharger.
You need more than 500 miles to reap the benefits of what you have.
dipstick
Kenny Snyder (RIP)
La Center, WA, USA
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1958 MG MGA 1500 Coupe "Rosie" 1970 MG MGB GT "Pat's GT" 1971 MG MGB "Gifted To Me" & more |
Oct 20, 2014 08:23 AM
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Lose weight.
Aluminum engine backplate
Hi-torque gear drive starter
Aluminum radiator
Light alloy BBS 11# rims
Single 12v battery
Aluminum hood
Aluminum flywheel
7-1/4" Button clutch/pressure plate
Aluminum drive shaft tube
Gun drilled rear axles
Rear disc brakes
Aluminum fuel tank
Light fuel load
Light spare tire (Saab?)
Aluminum jack (Porsche 944)
Aluminum exhaust tubing
Thin/sheet metal headers
Nylon front fender bolts & washers
Lose one horn
Lose the radio
Lose the back seat
Be safe out there.
Kenny
Aluminum engine backplate
Hi-torque gear drive starter
Aluminum radiator
Light alloy BBS 11# rims
Single 12v battery
Aluminum hood
Aluminum flywheel
7-1/4" Button clutch/pressure plate
Aluminum drive shaft tube
Gun drilled rear axles
Rear disc brakes
Aluminum fuel tank
Light fuel load
Light spare tire (Saab?)
Aluminum jack (Porsche 944)
Aluminum exhaust tubing
Thin/sheet metal headers
Nylon front fender bolts & washers
Lose one horn
Lose the radio
Lose the back seat
Be safe out there.
Kenny
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