Newbie- Just getting started
Hello. I've owned my 78 B Roadster for about a year. Love the car, great shape, everything works, no rust, well taken care of by the previous owners. Stock 1800 motor, desmogged with the exception of the charcoal canisters. Non-OD tranny, Pacesetter header with a Solex 34/34 downdraft carb. (originally sold as a Weber stickered DGV-like carb).
When I got the car, it had little power, hesitated, hiccupped on accelaration, etc. I replaced the dizzy with a recurved 25D from Jeff Schlemmer, rejetted the carb (it was seriously underjetted and now it runs pretty good). Much more fun to drive! But the motor has 98k miles on it and I figure it's going to need a refresh in the next year or so, If I was to rebuild the motor, I would probably include some performance enhancements, mild cam, etc. But in the end, I'd still have a 4 cylinder with no OD that turns 4000 RPM on the highway. So I was thinking....I'm not a purist, the car already isn't stock, why not drop a 3.4 V6 and a 5 speed in it? I've been reading everything on the forums about the conversion and it doesn't sound like it would be too difficult. My first goal is to get all the parts together before I begin so I can keep driving. Once I get the parts, I'd like to get the conversion done to just get it running and driveable and then do any performance enhancements to the motor afterwards as budget and time allows. From what I've read, it's seems that you should have a well built tranny first, so I would have that thoroughly checked out before I install it. I'm putting together a list of required parts and am sure I'll have lots of questions. A few I have now: 1) FWD or RWD 3.4 V6? What's the benefit of one over the other? Will either bolt up to a T5 with the right V6 bell housing? Any particular years work best? Other than top end work, what tasks can be done on the 3.4 with it in place (i.e. can you remove the pan without pulling the motor?) 2) EFI or Carb? 3) Ford T5 or GM T5 (sounds like V8 version is the way to go with my stock rear end), what's the difference between the two? Any particular years work best? Looking forward to your opinions and getting started. Thanks, Doug |
Re: Newbie- Just getting started
Here is the scoop as i see it. Others can add to it and you can make your own decision.
FWD 3400/3500 Advantages Lots of these engines around especially the 3500. The 3400 had intake gasket issues and lots of them got wrecked. The 3500 and 3400 have aluminum heads making them lighter than the old 3.4 iron head engine. The 3400 and 3500 have better breathing heads and intake systems. The 3500 is better than the 3400. The 3400/3500 have higher horsepower ratings then the old 3.4 iron head engines. I put a 2003 3400 in my TR6 and I am going to put it on a dyno this summer. The 3500 according to Marc at British car Conversions will put out about 235 hp. You cannot beat modern EFI for reliability and tuneability and decent gas mileage. The 3400 is the easiest to convert to RWD the 3500 is a little more work. I bought a brand new Ford T5 transmission for my car and it shifts very nicely. The Ford T5 from a 1979 to 1993 V8 Mustang will work quite well Disadvantages The biggest bugaboo is the electronics. I am fortunate to have a very smart friend that is good with electronics and computers and he reconfigured the existing 3400 OBDII engine harness and I paid a local tuner shop to reprogram the ECU. If you are not able to do the above type stuff then you will have to pay someone to do the whole thing or you buy a dumbed down OBDI engine harness and programmed ECU from an outfit like British car Conversions. If you are interested in going this route you can contact Marc Traylor at British Car Conversions. I bought some of my parts from him for my conversion. The older RWD iron head 3.4 engines can be found with EFI and possibly the transmissions, this makes the whole job easier however the Camaro transmissions have a very low first gear ratio. The older EFI is easy to deal with as you just have to bypass the chipped key. If you want to go this route with an older Camaro engine with EFI the person to talk to is Brian McCullough at BMC British Automobile. The simplest route is to go with a small 4 barrel carb and forget about the complexities of EFI. You can contact Bill Guzman at Classic Conversions and he will give you all the info you need to go the carb route. Check out his website and you will see his MGB that he has done up quite nicely. I hope this is helpful. Cheers Byron |
Moderator Curtis Jacobson Portland Oregon (4577 posts) Registered: 10/12/2007 02:16AM Main British Car: 71 MGBGT, Buick 215 |
Re: Newbie- Just getting started
Welcome to BritishV8!
I agree with Byron that "you cannot beat modern EFI for reliability and tuneability and decent gas mileage." Furthermore, in the case of 60-degree V6s, retaining a stock EFI system will help with hood clearance. |
Re: Newbie- Just getting started
Thanks for the info. Lots to learn.
I'm torn between the efi and carb option. Can the FWD 3.4 with aluminum heads be fitted with a standard intake manifold and carb? |
Re: Newbie- Just getting started
Doug I am not sure if you can bolt a manifold for a carb on a 3400.
Another option is to go with the iron head 3.4 and go with a bolt on Edelbrock efi system. Check out Gary Walker's car [www.britishv8.org] Send Gary an e-mail and get the low down on this system If you go with this system then you can bypass the complexities of reconfiguring an engine harness and getting the ECU reprogrammed. Cheers Byron |
Re: Newbie- Just getting started
Don't know where Curtis get his info :-) There is no clearance issues with either the FI or Carb.
The RWD is perhaps the easiest to install either FI or Carb. The 1978 is an easy install no messing with FWD converting to RWD. There is lots of support for the FI Brian has a harness that is ready to play, making the install rsimple. The carb will fit under the hood and yes it would be simpler than FI since there is no wires etc... Tuning is not complex, I have all of the needed info to make it run smooth. FI is just plug in and drive. so....which one is cheaper, some claim that it is a push, I agree with that statement. One mistake that many make is the following: FI Fuel tank is not clean Used all sensors will have the tendency no to read correctly and need to be replaced, cost goes up. Need an in-tank fuel pump or a good external set up. Not done properly can cause problems. Need new fuel lines; feed, return lines and fittings Carb, Fuel tank is not clean Using old fuel feed line Buying a bad used carb. Fuel injection done correctly is a good thing Properly tune carb is also a good thing. |
Re: Newbie- Just getting started
Thanks for the response. I'm thinking that initially, I'm going to keep it simple and go with an iron head V6, carbureted and look to upgrade later.
I'm looking for a short block and have talked to a recommended local machine shop about the cost of boiling out, magnafluxing, measuring, boring cylinders grinding the crank, checking out the heads etc., as necessary to get me a good start. Thinking about a mild cam when putting it all back together. Questions about transmissions... I'm planning to retain my stock rear end and use a T5 from a V8 Mustang or Camaro/Firebird to get the gearing I want. I put about 6000 miles a year on my B. What is the benefit of a world class transmission vs. a non W/C? Obviously the W/C is better constructed, but are there inherent problems with the installation/performance of a non W/C? Also, I've read about different length input shafts depending on the year and application. Which ones work with a standard V6 bell housing and position the shift lever in the existing hole in the tunnel? Thanks, Doug |
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Re: Newbie- Just getting started - update
I met with Bill Davidson last weekend and took a look (and ride) in his GT. All I can say is WOW!. Gotta get me some of that!
So a bit of progress. I've got a rebuildable motor being delivered to the machine shop today. 3.4 from a 94 Camaro. He's going to hot tank, magnaflux and measure everything so we can determine what needs to be done to it. Questions: 1) I anticipate replacing the stock cam with a mild street performance cam. What's the performance benefits between the 240/252/260 duration cams? 2) If I keep the current 1.5:1 rocker arms (may go to 1.6:1 roller rockers in the future, is there any issue going with a higher lift cam now that won't be a problem with the higher ratio rocker arms in the future? I don't plan to do anything other than a valve job to refresh the current valves if necessary. 3) I also have a T5 transmission out of an 85 V6 Camaro to pick up. Lower gearing than I would have preferred, but the overdrive is taller than the standard V6 tranny, so I think I'll be fine. In the future I'm planning to bolt it to a late 80's S10 bell housing that has the starter pocket on the right side and the mount for an external slave cylinder on the left. Will the S10 slave cylinder fit with that set up? Or do I need to find something off another vehicle and fab up a bracket of sorts. I really don't want to go with a HTOB. Thoughts? Thanks, Doug |
MGBV8 Carl Floyd Kingsport, TN (4514 posts) Registered: 10/23/2007 11:32PM Main British Car: 1979 MGB Buick 215 |
Re: Newbie- Just getting started
Quote: In a light sports car with a mild to moderate V6/V8? Not at all. |
Re: Newbie- Just getting started
Main difference is the WC has stronger bearings/holders. Even with the non WC, you will not be able to get enough power to tear it up. Your tires will go first!
If you get the stock SFI setup it is very simple to install. S10 bell will work. Saves the hassle of modding the shifter also. Took 4000miles for my HTOB to stop squealing, so I understand not wanting one. So you rode in a GT. Just wait until you don't have that extra weight! lol |
mgb260 Jim Nichols Sequim,WA (2465 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Newbie- Just getting started
The V6 T5 will work good with the 3.07 or 3.31 after market rear gears. I prefer the 3.31 if you have the 3.5 or 3.75 first,. If the 4.03 first you need the 3.07. Robert Kirk has the 3.07 and Basil has the 3.31.
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Re: Newbie- Just getting started
Basil can also get the 3.07. I would personally order from Basil because he gets the gears from Germany and not China. The quality of the gear is perfect.
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Re: Newbie- Just getting started
Good info. Thanks
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