Original engine or M30B35 replacement

John-T

John-T

Well-Known Member
Site Donor $
Messages
105
Reaction score
46
Location
Los Angeles
I have been looking for a few months now for a nice E9 for weekend driving. As a newbe I have been reading many many posts here trying to familiarize myself with the issues before jumping in.
I have read may treads regarding the engine upgrade to a B35.

To narrow down my search my question to the forum is if you had a choice between a car with original carb / engine and one already upgraded with the m35 which one would you go for?
(lets assume both cars are in basically in the same condition, rust, interior and exterior paint).

Thank you in advance and looking forward to your comments.
John
 
John,

that really depends on what your ultimate goal is. if you are buying a 'collector' car then you want a matching numbers engine / car with original carbs. if you are wanting a great car with more modern injection / engine electronics - then go with the b35 ... or if you want a more vintage look and great sound, go with a standard engine with triple webers and a better cam. both are fun

the bottom line is @Breiti 's advice is correct ... but the best car you can with little / no rust, great chrome and a great interior. that is the most expensive to solve later ... the mechanicals are easier with more options. buying a great mechanical car with an ailing body means you have big expenses ahead.
 
To reiterate Scott's comment, seek the car that is in the best possible condition emphasizing the body and cosmetic parts. Body work on these cars is expensive, and cosmetic parts are difficult to source. Mechanical parts are readily available and it is far easier to do mechanical work yourself, or to find people to do mechanical work than it is to either do cosmetic work yourself or find good people to do cosmetic work. Frankly, which engine is in the car is pretty far down the list because it is not that difficult to change to another engine later.

When I bought my car, my number one priority was finding a car with as little rust as possible. Next, I wanted a car that was as complete as possible. And it was a huge bonus that I found a car being offered for sale by a long term owner (The prior owner of my car owned it for forty years). Having said all that, I spent almost three years looking for my car.

Some additional tips from my car search - seek out BMW car gatherings where coupes are likely to show up and make an effort to meet and talk to current e9 owners. Many of these cars sell without being advertised, and you might find one for sale. Or, you may find someone who is willing to show you specific things to look for when buying a coupe. At a minimum, you will meet some very nice people.

Another thing I did when looking for my car is I followed closely all the cars for sale in this forum. What was particularly instructive was to study the comments that coupe owners made and to see how they were looking at particular cars.

Lastly, ask for help when you find a car you may want to buy. Several people here were extremely generous with their time in helping me acquire my car - this is something many forum members do for newbies. I have never seen a situation where someone on the forum took a deal away from a potential buyer, and I have seen a potential buyer get scammed out of his entire purchase price in part because he didn't want to ask us for help out of fear we may have snapped up his deal.
 
Last edited:
John-T said:
I have been looking for a few months now for a nice E9 for weekend driving. As a newbe I have been reading many many posts here trying to familiarize myself with the issues before jumping in.
I have read may treads regarding the engine upgrade to a B35.

To narrow down my search my question to the forum is if you had a choice between a car with original carb / engine and one already upgraded with the m35 which one would you go for?
(lets assume both cars are in basically in the same condition, rust, interior and exterior paint).

Thank you in advance and looking forward to your comments.
John
Click to expand...



i agree in all that was previously said, very good advices there, first best possible car as to body and trim both int and ext.

but as i look closer to your question you mentioned: "(lets assume both cars are in basically in the same condition, rust, interior and exterior paint)."

the original M30B30 equipped with original zenith carbs is a superb, real, original, and excellent choice.

i wont say the other option is a bad one, but to keep the original thing just as it was, it is something
 
my other recommendation is to NOT be in a rush. establish your budget and don't fall in love with the first car you find ... well, unless its just amazing. remember a pretty car can still hide a world of sins that won't go away.

before you buy, get a list of people who can do a proper PPI for you, if you like a car ... hire one of the right guys to look it over, put it on a lift and run a few tests. its money well spent. there are a few individuals in the LA community that know a thing or two about these cars. forum members in the LA area can point you in the right direction. if you are looking at one in Orange Co., message @HB Chris, he can tell you who to talk to. if you are looking in San Diego, call Carl Nelson. if you find a car in the SF Bay area - talk to / hire @sfdon and have him look at it.
 
rsporsche said:
my other recommendation is to NOT be in a rush. establish your budget and don't fall in love with the first car you find ... well, unless its just amazing. remember a pretty car can still hide a world of sins that won't go away.

before you buy, get a list of people who can do a proper PPI for you, if you like a car ... hire one of the right guys to look it over, put it on a lift and run a few tests. its money well spent. there are a few individuals in the LA community that know a thing or two about these cars. forum members in the LA area can point you in the right direction. if you are looking at one in Orange Co., message @HB Chris, he can tell you who to talk to. if you are looking in San Diego, call Carl Nelson. if you find a car in the SF Bay area - talk to / hire @sfdon and have him look at it.
Click to expand...
Great advice. Thank you!

Could you please PM me sfdon's phone number.
 
I’ll chime in as well. It’s just an opinion anyway. Given equal quality cars in the body/chrome/interior departments, I would always, always, always pic a fuel injected car over a carburated car. In fact I’d say specifically that the later motrinic 1.3 is a stand out in terms of drive-ability and durability. There are many carb gurus on this site. If I had their knowledge, id most likely lean that way. Additionally, many here have become well versed in the carbs by necessity. There seem to be fewer and fewer mechanics who can work on them properly and your proximity to one of these individuals should play into your decision making. I prefer to turn the key on my cars and enjoy them to their fullest. Regardless of whether it’s 25 F or 105 F, at seal level or in the mountains. That means fuel injection for me and the latest version at that. SfDon has been a tremendous help to me getting my injectors, fuel rail, pressure regulator and wiring harness set to convert my car to an m30b35. It’s a numbers matching 2800 cs and I’m not concerned about any of that. I plan to keep the old lump and the carbs as well as the 4spd, even though they’ll most likely never see the light of day again. If you drive and travel, the way the cars were meant to be used as wonderful grand tourers, then I’d lean heavily towards the later model drivetrain.

Im a traditionalist in my visual makeup of the car however. I prefer more traditionally accepted classic upgrades to wheels, stance and interior. The great thing about a clean injection upgrade, if using classic intake runners, is that it can be disguised quite well and falls into line with factory period correct fuel injection.

I wish you the greatest of luck in your search and have fun wrestling with this dilemma, many wish they were in your shoes : ). Mark
 
Oldbmwcoupes said:
I’ll chime in as well. It’s just an opinion anyway. Given equal quality cars in the body/chrome/interior departments, I would always, always, always pic a fuel injected car over a carburated car. In fact I’d say specifically that the later motrinic 1.3 is a stand out in terms of drive-ability and durability. There are many carb gurus on this site. If I had their knowledge, id most likely lean that way. Additionally, many here have become well versed in the carbs by necessity. There seem to be fewer and fewer mechanics who can work on them properly and your proximity to one of these individuals should play into your decision making. I prefer to turn the key on my cars and enjoy them to their fullest. Regardless of whether it’s 25 F or 105 F, at seal level or in the mountains. That means fuel injection for me and the latest version at that. SfDon has been a tremendous help to me getting my injectors, fuel rail, pressure regulator and wiring harness set to convert my car to an m30b35. It’s a numbers matching 2800 cs and I’m not concerned about any of that. I plan to keep the old lump and the carbs as well as the 4spd, even though they’ll most likely never see the light of day again. If you drive and travel, the way the cars were meant to be used as wonderful grand tourers, then I’d lean heavily towards the later model drivetrain.

Im a traditionalist in my visual makeup of the car however. I prefer more traditionally accepted classic upgrades to wheels, stance and interior. The great thing about a clean injection upgrade, if using classic intake runners, is that it can be disguised quite well and falls into line with factory period correct fuel injection.

I wish you the greatest of luck in your search and have fun wrestling with this dilemma, many wish they were in your shoes : ). Mark
Click to expand...
Thanks Mark for the reply. Honestly the more I read and understand from the old posts on the forum I'm beginning to lean more towards a nice updated engine and fuel injection system. I'm no purist, just want a car to enjoy and take on road trips with not too much headache, I think this is the way to go for me too.

Thanks again for chiming in, and I appreciate your opinion.

John
 
Insight on Carb vs FI….

Go to Germany. I would guess 90% of the e9 coupes on the road are fuel injected.
Carbs are seldom seen.
 
I own two dual carb'e cars, E9 and Lancia Fulvia.
The only drivability downside is that they have mechanical fuel pumps, so I have to crank way longer if the carb dries up by not driving the car for a week or so. Electric pumps would fix that.
Both are more consistent that my fuel injected E24, whose idle is always hunting, unhappy with O2 sensor, Idle Control Valve dies, and of course the dreaded wiring harness problems. Carbs do not really care if you have a bad ground. It is true that not many mechanics can deal with my carb'ed cars, but so far I had no need to tweak anything in more than 6 years. My E24 and E36 on the other hand have electronic injection drama every year or so.
There you have it, the contrarian view. Have 3 cylinders injected and three carbed so you can dramatize the cost of trying to please everybody.
 
I switched from dual carbs a few years back and went with a single 4-bbl. All my butterflies in one box, no synching, no funky linkage and wonderfully smooth operation. There is also that distinctive whooping when you open up the secondaries.
 
I recall 10 years ago I was sniffing for a coupe and found one locally. Took a million photos and having owned BMW's for 30 years, looked in all the right places for rust. I thought I was in the clear but called VSR to get Mario's opinion even though I did not even know him. He spent 20 min on the phone with me and at the end, knew the car and all of it's history and problems. Bottom line is that I would bet any car you look at, someone here knows a lot about where it has been so shoot a flare gun up on this forum when you believe you have found the right car and keep an open mind when the forum chimes in. Never seen a forum more helpful and on point.
 
Fuel injection can deliver superior fuel control over carbs, but early FI systems are quite old now and can be expensive and difficult to repair as it's hard to find people with the knowledge and parts are scarce and expensive. Original Zenith or aftermarket carbs can easily be rebuilt but a are little tricky to get properly tuned by you or will need a scarce knowledgeable soul.
As stated above, Motronic 1.3 is probably the best OEM FI system to get, all the needed parts can be taken from a donor car along with a bigger engine. Some people choose new fuel injection systems (Megasquirt) that are universal and customizable but at the cost of being non-standard which results in difficulty in finding support.

Bosch Fuel Injection Systems Book PDF
 

Attachments

  • Bosch Fuel Injection Systems Book Cover.png
    Bosch Fuel Injection Systems Book Cover.png
    3.8 MB · Views: 79
180HP carb setup (170HP if 2800CS) < 208HP M30B35 w/EFI Motronic 1.3.

If all things equal (which never happens), do the latter.

I got lucky and found a running/driving E34 535I w/90k miles for $500USD.
 

Attachments

  • engine-removal.jpg
    engine-removal.jpg
    241.5 KB · Views: 64
John - from the sound of things, reliability is one of your primary concerns. If so, I have a couple of comments.

First, in his first Hack Mechanic book, Rob Seigel wrote about making an old car reliable. In general, people who own used cars don't repair stuff until it breaks. This may work for a long term owner who knows a car's history, but when buying a very old car, this is not a good philosophy. In short, Rob suggests that you plan on a handful of repairs immediately after buying an old car. Build into your budget the costs to redo all the belts and hoses, replace the rubber brake lines, replace all the fluids, replace the battery and tires (depending on their age), etc. Replacing all the rubber parts in the suspension will add greatly to your driving experience. And with a carbureted car, updating your ignition parts can save a lot of "carburetor" problems.

Another important thing to think about is even if you can do a lot of your own mechanical work, you should find a good local BMW mechanic you trust as part of the process of buying a coupe. This can buy you a lot of peace of mind.
 
You must log in or register to reply here.
Back
Top