engine and drivetrain Fish or cut bait? Modify the 1600 motor or swap?

[arminyack]

Ok I've thought this over and over...so I'll open it up to a discussion to see what the opinions are. My '68 1600 w/ 34 ICH carb is a little lackluster on power. I have a 32/36 carb for it that i just rebuilt (it came with the car when i bought it in the obligatory box 'o extra parts). However, then manifold I have is for a 2002, with larger intake ports, so ideally, i'd need the euro e21 carb'ed manifold to match things up....which is proving to be more difficult than I thought.

 

Now I do have on an engine stand in my garage a long block from a '74 2002....its been languishing there for a while, as I decide what to do with it. Shall I rebuild it as I see fit (292 cam, higher compression, dual webers, etc) and swap out the 1600 motor for it (as the old saying goes.....there is  no replacement for displacement)?? I know some here who would cry heresy at such a thought, as the car is a largely intact & original 1600.

 

OR

 

Begin modifying my current 1600. The compression is good. leakdown tests are great. It burns no oil, no leaks....its seems to be a solid motor of which I know little about other than it is a matching motor for my car. I could port the 118 head to match a DCOE manifold (yes, DCOE's ARE going on either which way I go...I got addicted to them & there sound long ago....I miss it so), put on a 292 cam, etc...but then there is the question of compression ratio. Perhaps a 1.8i head would be a good replacement for the 118 head? I haven't done any calculations yet....just thinking out loud on how to increase the CR....

 

....so many options really....it makes my head hurt. 

 

So help me out here....how does the Senate vote!?

 

[Conserv]

1. Remove and save original 1600 block and 118 head.

2. Modify '74 motor to your heart's content.

3. Install '74 motor in your 1600.

4. Vroom, vroom.

5. 1600 block and head transfer with car to next owner (unless you have an "originality moment" before such transfer and decide to re-install the 1600 motor, balanced and blueprinted, of course, and with an original 1600 manifold and Solex).

Steve

Edited March 30, 2015 by Conserv

[Mark92131]

Dump the Weber 34/ICH Carb and find an original 36-40PDSI Solex, rebuild it with a kit from La Jolla Independent, install it on your 1600 motor.  It will return it to a stock condition and you can better assess if you need to take the next step (installing the 74 motor and adding all the performance modifications).

 

Mark92131

[Preyupy]

Using the 1.8i head will significantly LOWER the compression ratio on that engine unless you come up with some custom pistons that fit that combustion chamber shape. You also have the issue of a combustion chamber designed to fit on a 89mm bore sitting on a block with a 84mm bore, you will need to use the 89mm head gasket and you will have a strange squish zone and flame front.

[Mike Self]

Dump the Weber 34/ICH Carb and find an original 36-40PDSI Solex, rebuild it with a kit from La Jolla Independent, install it on your 1600 motor.  It will return it to a stock condition and you can better assess if you need to take the next step (installing the 74 motor and adding all the performance modifications).  

 

 

Second Mark's motion.  Try your stock engine with the proper carburetor before going to all the trouble of swapping engines.  That Weber 34 is meant for a 1.1-1.4 liter engine (like a Fiat 1100) and really strangles your 1.6 liter engine.   My 850cc Renault is very happy with a 32mm Solex--that's only 2mm smaller than the Weber 34 but only half the displacement of your 1600.

 

With the proper carb and the 1600's 4.11 diff, the performance should be pretty good, only falling off at higher speeds due to the axle ratio.  But unless you install a 3.64 diff with the 2002 engine, you're gonna have the same high revs at highway speeds; you'll just get there a little quicker.

 

cheers

mike

 

BTW I have a spare 118 head if you ever need one...

[eurotrash]

I second the build and swap plan. Much better equity in the end. And a monster fun factor in between.

Edited March 30, 2015 by eurotrash

[Conserv]

You poor fellow: you are addicted to DCOE's. I'm unconvinced a single-barrel downdraft -- yes, even if it is the correct single-barrel -- will cure your ills!

Get well soon!

Steve

Edited March 30, 2015 by Conserv

[arminyack]

You poor fellow: you are addicted to DCOE's. I'm unconvinced a single-barrel downdraft -- yes, even if it is the correct single-barrel -- will cure your ills!

Get well soon!

Steve

Yes! When I first met my wife, I took her for a spin in my '63 Triumph TR-4.....dual webers installed. We got on the freeway, and after we had accelerated down the entrance ramp & were at speed, she asks me "Why does your car sound like a vacuum cleaner?"

[Slavs]

Forgive me, but you sound like you've bought into some of this mainstream tuner lingo; "292 cam, 32/36 Weber, 1.8 head, duel Webers etc.

 

1. As stated above, you will ruin your motor if you bolt on that 1.8i head which has much larger combustion chambers which don't match your pistons and which will drastically lower your compression ratio and power. The 118 head on the 1600-2 is an excellent head. Your 118 head in stock configuration was used on both the 1600ti and 1800ti. In modified form with a 300 degree cam, larger intake valves and dual valve spring, it was used on the radically tuned 1800tisa. SO, your head is more than up to the job. Don't ruin your engine by bolting something on to your car because you heard from someone else that it works well on a liter. Even on a 2 liter, you would need custom pistons to match the size of the combustion chambers. And most aftermarket forged pistons are awful on the street. They burn a lot of oil. There is a reason the factory used high quality cast pistons.

 

2. The 292 cam will give you a lumpy idle, and you will loose much needed low end torque and power. BMW used the same stock cam (264 degrees) on all its models including the 1600, 1600ti, 1800, 1800ti, 2002, 20002ti and 2002tii. The ti and tii engines are good for an additional 20hp due to a slightly higher compression ratio and use of dual sidedraft carbs or fuel injection. Despite what many people on this board will tell you, stay away from high duration cams unless you are building a race motor. And if you choose this route, buy a quality engineered race cam made either by the factory, Schrick or Alpina.

 

3. Sidedraft cams can work well with even the stock motor if jetted correctly. Alpina sold sidedraft kits for the stock motors. With these kits, the stock motors yielded an additional 10-15hp. In some of the Weber DOE manuals, there is a jetting and choke prescription for the 1600 Alpina for the stock 1600 motor.

 

4. Don't port your head to match 2 liter manifolds. You will ruin it. In such a case you will loose horsepower due to decreased velocity and compression. There are plenty of sidedraft manifolds that match the 118 head. If you are hell bent on sidedrafts, you can obtain the manifolds from the Neu Klasse 1800ti which has identical ports as your car. The 1800ti was imported into this country in abundance. You can call the dedicated BMW wrecking yards where you can find these manifolds.

 

5. If you are not running a 5 speed overdrive, don't drop in a 2 liter unless you also plan on swapping the diff to a 3.64. The 2 liter engine is a bad match with the 4.10 ratio 1600 diff unless you use the overdrive 5 speed from the 320i. The 1600 is much happier at high revs compared to the 2 liter because the stroke on the 1600 is much shorter. The 2 liter really hates life with the 4.10 diff and only a 4 speed. It feels like it wants to explode at 65mph. Your 1600 has a 4.10 longneck. If you use the 2 liter, the only 3.64 longneck diff was used on only the 68 2002. They are not that easy to find. If you want to use the more readily  available  short neck 3.64 diff, you would need to swap your entire rear subframe and the driveshaft. Also remember that your rear drums are smaller, and you really need the larger 02 drums to keep your brakes on par with the liter.

 

6. If I was you, I would use the stock matching numbers 1600 motor. otherwise be prepared for some major work and juggling.

 

And last, don't pay attention to some of this lingo coming from many of these Yahoos who have little clue what they are talking about.

 

[Fatherof3]

If you build it for the next owner it will end up with the next owner and you will still be left wanting

[danco_]

If you swap in a larger, later 2l from a 2002, take into consideration the heater core hose diameter differences. This is a pain to resolve correctly, but can be done. You probably have an early heater valve as well, which will need to be taken apart and cleaned/lubricated if you plan on reusing. Otherwise, if you go through with an engine swap, be ready to swap out your heater core, or make the necessary preparations for hose adapters. 

[arminyack]

Forgive me, but you sound like you've bought into some of this mainstream tuner lingo; "292 cam, 32/36 Weber, 1.8 head, duel Webers etc.

 

1. As stated above, you will ruin your motor if you bolt on that 1.8i head which has much larger combustion chambers which don't match your pistons and which will drastically lower your compression ratio and power. The 118 head on the 1600-2 is an excellent head. Your 118 head in stock configuration was used on both the 1600ti and 1800ti. In modified form with a 300 degree cam, larger intake valves and dual valve spring, it was used on the radically tuned 1800tisa. SO, your head is more than up to the job. Don't ruin your engine by bolting something on to your car because you heard from someone else that it works well on a liter. Even on a 2 liter, you would need custom pistons to match the size of the combustion chambers. And most aftermarket forged pistons are awful on the street. They burn a lot of oil. There is a reason the factory used high quality cast pistons.

 

2. The 292 cam will give you a lumpy idle, and you will loose much needed low end torque and power. BMW used the same stock cam (264 degrees) on all its models including the 1600, 1600ti, 1800, 1800ti, 2002, 20002ti and 2002tii. The ti and tii engines are good for an additional 20hp due to a slightly higher compression ratio and use of dual sidedraft carbs or fuel injection. Despite what many people on this board will tell you, stay away from high duration cams unless you are building a race motor. And if you choose this route, buy a quality engineered race cam made either by the factory, Schrick or Alpina.

 

3. Sidedraft cams can work well with even the stock motor if jetted correctly. Alpina sold sidedraft kits for the stock motors. With these kits, the stock motors yielded an additional 10-15hp. In some of the Weber DOE manuals, there is a jetting and choke prescription for the 1600 Alpina for the stock 1600 motor.

 

4. Don't port your head to match 2 liter manifolds. You will ruin it. In such a case you will loose horsepower due to decreased velocity and compression. There are plenty of sidedraft manifolds that match the 118 head. If you are hell bent on sidedrafts, you can obtain the manifolds from the Neu Klasse 1800ti which has identical ports as your car. The 1800ti was imported into this country in abundance. You can call the dedicated BMW wrecking yards where you can find these manifolds.

 

5. If you are not running a 5 speed overdrive, don't drop in a 2 liter unless you also plan on swapping the diff to a 3.64. The 2 liter engine is a bad match with the 4.10 ratio 1600 diff unless you use the overdrive 5 speed from the 320i. The 1600 is much happier at high revs compared to the 2 liter because the stroke on the 1600 is much shorter. The 2 liter really hates life with the 4.10 diff and only a 4 speed. It feels like it wants to explode at 65mph. Your 1600 has a 4.10 longneck. If you use the 2 liter, the only 3.64 longneck diff was used on only the 68 2002. They are not that easy to find. If you want to use the more readily  available  short neck 3.64 diff, you would need to swap your entire rear subframe and the driveshaft. Also remember that your rear drums are smaller, and you really need the larger 02 drums to keep your brakes on par with the liter.

 

6. If I was you, I would use the stock matching numbers 1600 motor. otherwise be prepared for some major work and juggling.

 

And last, don't pay attention to some of this lingo coming from many of these Yahoos who have little clue what they are talking about.

The 1.8i head thing was just a spur of the moment thought...I never looked into it at all, just an idea I wanted to follow up on.

 

The main reason why I haven't done a thing with the '74 motor I have (which basically fell into my lap) is the reason you stated....the rear end. I would have to re-do EVERYTHING back there, and I'm not even sure I want pursue that route, I shall explore the rev-happy 1600 motor set up first. 

 

Thanks for the input!! It really helps a lot....I will be further looking into a 1800ti manifold, and jetting presciptions that you spoke of...

 

BUT FIRST...I found myself a good Solex 36 40. I'll stick that on, get it dialed in, and roll with that for a while

Edited March 31, 2015 by arminyack

[arminyack]

Got the Solex in! Definitely an improvement over the 34 ICH. I have a bit of tuning to do on it, and the idle is wanders a bit ( I think due to wear in the throttleshaft) Otherwise, it drives fine, and the car makes more power.

 

I just sourced a euro 316 e21 double barrel carb manifold in England..I managed to find a guy who was parting one out, so he is sending the manifold my way. So I have the 32/36 option as well.