292 cam in a 1600

[Oldtimerfahrer]

Yeah, but you cannot recover the head, block is not affected... or at least its economically prohibitive to recover the head. You can sell the whole thing as a package I suppose.

Andrew

[Conserv]

44 minutes ago, mccusername said:

...But this engine block is not original to the car anyway, so I figure if it ends up being too aggressive for me, I can sell the engine and try something else.

 

Given those facts, Michael — and the apparent availability of a few good 118 heads, since so many 1.6-liter engine’s were swapped out for 2-liter engines — knock yourself out! And if it isn’t to your taste, somone will want a hot-rodded 1.6 liter!

 

Best regards,

 

Steve

 

 

 

[edgefinder]

halboyles, Your caliper is measuring about right in the first post with pics but in the next post it looks to be 4 or 5mm too big?? What am I missing?

 

[tisalover]

I have been running the 300° cam in the BMW 1800 TI/SA , and also in 2L applications. I think it's plenty smooth, and it pulls nice when things are wide-open. Expect to give up a little bottom end, but the 1600 is a sweet revving motor. 40 mm DCOE Weber carburetors are probably perfect, 45s would make it a flat out track car and not so nice for the street. It's good to have some torque and midrange on the street. And the look has undeniable motoring sex appeal! 

5B59EE53-BC8B-45A2-BB24-99199B7CE33F.heic C8E79ED7-9DF2-46A0-8873-419F86D2C8B4.heic FEB2EB4D-BAC3-4C2E-9B23-85AE2C7773E6.heic

[Slavs]

I've had a 292 regrind or something veru similar in a 2 liter. And, I didn't like it. It had a lumpier idle and contributed to lower fuel economy. Some people's impression of a lumpy idle may be different from yours. I would personally trust the factory's and Alpina's 300 degree cam more than the 292. And, it is more historical and period correct. The street version of the 1800TISA had one. I believe the TISA motors were available in various version from 130bhp to 170bhp.

 

There were two versions of the 300 degree cam; one where you had to bore out the head to accommodate the larger journals of the 300 degree cam, and another version where the 300 degree cam has the same size journals as the stock cam, so just a direct replacement. I think the direct replacement was the one available through Alpina. Glen of 2002 AD has an early Alpina kit for a 1600 installed on his 1600 Cabriolet. He has the Weber carbs, manifolds and square air cleaner box, a rare piece. He also has the 300 degree cam installed. I believe it’s the direct replacement version.

 

The 1800ti and 1600-2 and 1600ti used the same size valves. So, I think the valves in the 118 head of the 1600-2 and 1600ti are more than adequate.  With the 1800ti you probably loose the unique smoothness of the 1600. This is due to the fact that the early NK 1800 motors were essentially 1600s with a longer 80mm stroke. That’s what you get when you mate the 1600 block with a 2002 crank. You just have to have the specific 84mm 1800 pistons designed for the 80mm stroke. They look like 1600 pistons, but have a different pin to deck measurement. The “116” head of the 1800ti is interchangeable with the 118 head of the 1600. The top of the pistons have the same shaped raised crown. The 118 head is more modern with the more familiar timing chain tensioner and plastic guides. The 116 head has a sprocket which serves as the tensioner and guide. The 116 head has simple wedge shaped combustion chambers  and uses a hollow cam which is lubricated from within. There is no oil sprayer bar. The 1800ti motors are more common in Britain where the vintage racing regulations are more stringent and where the 1800 motor must be used by many of the NK cars. The engine builders opt for the more modern 118 head. They sometimes fit the larger valves from the 121 head. But, I don’t think you need the larger valves on your 1600. And, the crank of choice is  the 2002 crank with 8 counterweights. At the time of their production the 1800 and 1800ti NK cranks had 4 counterweights. I believe the 8 counterweight crank was first introduced at some point during 1800TISA production. By the time the 2 liter motor was developed all 80mm cranks had 8 counterweights. The 1500 and 1600 cranks have 4 counterweights because that is all that is needed with 71mm short stroke cranks. None of the short stroke M10 motors have 8 counterweights.

 

In 1968 BMW redesigned their 1800 motor to include the 89mm bore 2002 block with the 71mm crank of the 1600. This resulted in a smoother running motor. This motor was used in the NK 1800s from some time in 68 to the end of their production run, probably in 71 or 72. It was also used in the 1802 and later in the 1.8 versions of the e21 and e30. It is interesting to note that BMW used the same 118 head of the 1600-2 on their 1600s and 1800 motors of late 60s - early 70s vintage.

 

Going back to the 1600-2, it uses larger intake valves than their previous version of the 1600NK four door.

According to literature the larger intake valves ( 2mm increase) yielded a 2hp gain.  Parts vendors and writers often incorrectly cite NK 1600 engine specs and horsepower stats when referring to the 1600-2 which has 85bhp compared to the 83bhp of the earlier version of the motor as used in the NK 1600. People have erroneously purchased NK1600 valves when rebuilding their 1600-2s to find the valves are too small. This is one of the reasons BMW renamed the 1600-2 to the 1602 in 1970, so that people and parts vendors stop confusing the NK 1600 of 1964-66 to the 1600-2 of 1966-76. You actually already have enlarged valves in your "118" 1600 / 1600ti head. They were borrowed from the 1800ti.

 

The M10 motors started with the NK 1500 which has the short 71mm stroke with 82mm pistons. So the 1600 with its 84mm bore and 71mm stroke  is essentially just a slightly bored out 1500NK. But before they developed the 1600, they first made a jump from 1500 to 1800 by increasing bore from 82mm to 84mm and increasing stroke from 71mm to 80mm. They then developed the 1600 by combining the 84mm bore of the 1800 with the 71mm crank of the 1500. After this they developed the 2 liter by increasing the bore of the 1800 from 84mm to 89mm with the stroke remaining the same at 80mm.  In 1968 they redesigned the 1800 motor to a big bore short stroke combination (89mm bore, 71mm stroke). They did this to create a smoother running 1800.

 

I know I've gone on a tangent, but since we are talking about engine specs, you can trace M10 engine evolution from 1961 onward fairly easily. Your 1600-2 and 1600ti is interesting in that it includes both, early 1500 components with a more modern head. The early 1500 holdovers include the crank and clutch assembly. I know the 1800 and 1800ti NK cars used the same flywheel,pressure plate and clutch as the 1600-2 and 1600ti. And the 1500 and NK 1600 also seem to have used the same clutch according to the pics I've seen. When they made the 2nd generation 1800 in 1968, BMW introduced the 215mm clutch.

 

These early motors are nearly forgotten in the US due to the popularity and flexibility of the 2 liter which gives you that mid-range freeway on-ramp pull. Historically though, they are very significant. The M10 was first designed in short stroke configuration which also has its advantages. And, the M10 short stroke motors have very different characteristics from their long stroke cousins. I'm curious what the long stroke 1800 and 1800ti feel like in comparison to the 1600 and the 2 liter. They have the smaller clutch and pistons, but torque distribution is more similar to the 2 liter. Perhaps someone here can weigh in on the subject. BMW redesigned the 1800 in short stroke configuration for a reason in 1968. So, there is a lot to be said about the silk smooth short stroke M10 motors.

Edited September 8, 2020 by Slavs

[tisalover]

 Excellent!

 

Slavs thank you so much for discussing the M 10 motor evolution.

I have never read it so concisely in one place, and really appreciate your expertise and understanding. 

 

?

[edgefinder]

Back to the original question yes a 292 is probably the best starting point if you want a sporty motor. The driveability issues folks have with bigger cams relate to the large diameter manifolds and ports that the preferable heads with bigger valves have. If you start with a smaller ports and valves head theres a lot of work to get them sized better. If starting with a more desireable head the intake port is too big with no velocity. Most people modify 2L motors for whats easiest to get and with the bigger amount of air flowing through the usually too big diameter intake ports it doesnt cause as many problems that a smaller motor will have. A bigger bore or longer stroke will add velocity to big ports so its a win win and popular to do.

 

Building a 1.6L for sidedraft 40's you want manifolds or ports that taper smaller up to the valve pocket. The valve pocket should have a larger area or volume to slow velocity and gain pressure to more evenly blow around valve head. The throat at bottom of valve seat should be near 85% of valve diameter for anything but race only approaching 2 horse per liter. If you drive one done right you won't ever think of using a puny stock cam again. 

 

[edgefinder]

Slavs, there are 8 counterweight shortstroke forged cranks for both 1600 and 1800. I'm gathering parts for a small motor myself.

[Slavs]

On 9/6/2020 at 8:16 AM, edgefinder said:

Slavs, there are 8 counterweight shortstroke forged cranks for both 1600 and 1800. I'm gathering parts for a small motor myself.

 

As far as the 71mm crank is concerned;

 

 

All 71mm cranks which I've seen, including the forged ones and later cast versions used in the 1800cc motors of some e21 and e30 cars, have only four counterweights. If you can find info or a picture of a 71mm crank with 8 counterweights, I'd be interested in looking at it.

 

BMWs first 80mm cranks as used in the first generation of 1800cc motors 1963-66 mostly had the 4 counter weights. At some point of their production during 65 and 66 they started using the 8 counter weights. I believe they were first used on some of the 1800TISA cars. BMW first attempted getting away with just 4 counterweights to keep the crank and rotating mass light. But, the longer 80mm stroke coupled with the large horsepower output of the TISA motor probably necessitated the 8 counterweight 80mm crank.

 

But, there never really was a reason to add more counterweights to a short stroke 71mm crank even with the larger 89mm pistons of the 2nd generation 1800cc motor which appeared during the latter part of 68 or early 69. The motor is silk smooth with 4 counterweights, so why add more rotating mass ? It would just detract from its performance.

 

Some people have also suggested that 1600 cranks were not forged. All BMW cranks including the 71mm versions were forget until about 77-78. It's just that engine builders sometimes swap in a newer cast crank because the old forged crank is damaged. The newer cast cranks are readily available. Furthermore all the newer 71mm cranks are 8 bolt versions and use the 215mm clutch and flywheel, which is much cheaper and more readily available than the 200mm 1600 clutch which must be used on the 6 bolt 1600 forged cranks. Between 1970-76 BMW produced the forged 1600 crank with 8 bolts, but in the US the 1600 was imported only through 1972. So, the forged 8 bolt cranks for the 1600 are pretty sparse in the US. The alternative is the 8 bolt cast crank, cheap and available in large numbers.

 

Modern BMWs, with the exception of "M" cars, have cast cranks. They are quality cranks with good surface hardening, but they are never equal in quality to the forged cranks. Sure, new BMWs have more horsepower, etc, but some of the metallurgy is inferior. From the perspective of BMW and most automotive producers, the forged cranks are overkill and too expensive to produce for their ordinary street cars. But, this is not how they saw things back during the late 50s and early 60s when the BMWs pride and reputation for producing the highest quality parts were at stake.

 

 

Edited September 7, 2020 by Slavs

[NickVyse]

Great info Slavs - I love the 1600 in my early car and it always pains me when people buy a 1600-2 and by default chuck a 2 litre in it, they're missing out on some fun and taking away the unique character of the smaller engine. One m2 owner who also had a 1600-2 always remarked it was like a mini s14 (the way it loves to rev up), a statement that's stayed with me. 

 

So where's the original poster? Would love to know the outcome of his hot 1600.

Edited September 7, 2020 by NickVyse

[mccusername]

9 hours ago, NickVyse said:

Would love to know the outcome of his hot 1600.

 

C'est moi. The engine is done, the rest of the car is, um, ongoing. A 1600 block with original 118 head with small intake and exhaust valves, forged JE pistons at about 9.5, a BMW 300 degree motorsport cam with big journals, rebuilt Italian 40DCOE's with little bitty chokes, early Alpina intake manifolds and 'cracker box' air box. Original crank, flywheel, mechanical clutch and early 4-spd. Engine build overseen by Nate William at SCR.

 

The idea was to stick as closely as possible to the original Alpina equipment and formula for the 1600 engines. I haven't driven it much since the car isn't all the way done, and I was conservative with the RPM, but so far I love it. Very smooth and free-revving, as is the nature of the 1600. I was really concerned about a lumpy idle and I have no complaints at all. Maybe a hint more 'character' than stock but I wouldn't describe it as lumpy at all (should note that I'm using a 123 distributor as well). Quick, light and smooth!

 

Michael

[Slavs]

Michael,

 

That motor looks really nice. I really like the rectangular Alpina air filter box. They are rare as they pre-date the factory's cylindrical air cleaner canisters first used on the 1800ti in 1964.The first Alpina kits were designed for the NK 1500 back in 1962-63. And, that is where the rectangular air filter box first appeared. At some point Alpina started using the cylindrical "Ti" air canister, but they fabricated a bracket to mount on the strut tower bolts because all 02s with the exception of an original Ti or tii lack the mounting tabs welded by the factory to the side of the engine compartment. It was an easy solution. I don't know when Alpina made this switch or if they continued using both styles of air cleaner boxes. While the factory produced the "Ti" cars Alpina continued to produce kits and conversions in various degree of tune. The most basic kits just included the carbs, manifolds, linkage and air cleaner box. It was all good for about a 10hp gain on an otherwise stock motor. A bump in compression with Ti pistons added another 10hp while the 300 degree cam changed things significantly.

 

You've paid good attention to detail with that motor, including the T50 remote booster. Most shops which rebuild them don't bother in finishing the associated hydraulic cylinder in that Royal Blue, nor do they polish the tuna can. I also like the period correct oil filter. I have a few laying around, but I haven't used them yet. I changed my oil once every 2 months as I drove my 1600s extensively. So, I just stayed with the more modern oil filter. I've also noticed you've got the original 1600 specific fuel pump. I believe the 1600 and 1600ti used the same fuel pump. I use the same braided German fuel line on my cars. It works great, but when it goes bad you can't see the cracks, concealed by the braiding. You may just notice the line being damp from fuel.

 

Everything appears 6V in your car except for your battery. Is it a 6V battery ?

 

Are you using the Alpina Jetting prescription as a starting point for the DCOE carbs ?

 

Questions, Questions, Questions ?

 

The valves in the 118 head are not small. Think 1800ti. They are actually large as far as a 1600cc is concerned.

 

Slavs

 

 

 

 

Edited September 7, 2020 by Slavs

[Tommy]

Slavs - to my knowledge there isn't 71mm crank with 8 counterweights, but there is one pretty close. That is 72,6mm stroke S14 crank from 320is. I hoarded one for future plan but that's unlikely to realize. 

Edited September 8, 2020 by Tommy

[NickVyse]

That's a great engine Michael - just the sort of thing I had in mind for when I get round to my 67. Did you consider longer rods? Seeing as you had the pistons made I'd have picked up some 144mm rods, or even better the 150mm rods from the s14b20. Or did you want to stay true to what was available back in the day?

 

Nick

[mccusername]

6 hours ago, NickVyse said:

Did you consider longer rods?

 

Only briefly. I wasn't trying to keep things period correct on the internals or anything, but you have to draw the line on mission creep somewhere. Bang for buck, using polished/balanced OEM bits was how we chose to go.