Engine Options

[misterarj]

I am purchasing my first Roadster this Saturday. It is coming with the original 1600 engine and a U-20. The 1600 stopped running and the guy pulled it, the U-20 is all there but in pieces. So many new parts though, definately a bit of money went into getting all the U-20 pieces together. Am i better of to replace the 1600, repair the 1600, or fuss with assembling the U-20? I'm also not opposed to selling the U-20 to a collector that truly wants one and swapping in a different engine. What does everyone think? Thanks for your insight.

[S Allen]

My two cents---Go for the U20 if it is all there to be put back together. A 1600 is a robust little motor but a U20 definitely has some guts to it. You would probably spend close to $2000 to get the R motor(1600) rebuilt any way. That is if it is rebuildable to begin with. Depends on why it quit running. Did you get the 5 speed tranny, backing plate, tranny mount and drive shaft with the car? I would not bother putting a U20 in without a 5 speed. Good luck.

Steve

[kogi]

go for the U20!!! (like steve said, "only if you are going to mate it with 5spd")
i just finished my 66spl and it is a blast!!! you'll have to modify few things but but worth the effort.

good luck on your quest

ken
u20 w/solex

ps. steve... your icon is broken

[spl310]

OK, pardon my ignorance, but why not put a U-20 in a 4 speed car? Around town, it should be a bit more fun. On the highway it would make a difference, and I could see that argument. If the 4 speed is there, why not give it a try rather than modifying it for a 5 speed?

Just my thoughts.

Sid

[S Allen]

Okay Sid, I suppose you could run the U20 with a 4 speed but that 5th gear is pretty sweet. It can be done-I just would not do it but then different strokes for different folks. I prefer a stroked 2 liter R motor over the U20 any ways.

Steve

[CU Zcar]

I don't know this as fact but the 5 speed may also have better ratios for the U20 than the 1600's 4 speed. However the U20 will be more powerful than a 1600 (with equal mods) so even with compromised ratios you'll probably come out ahead. I'm running a 4 speed in my 280Z right now and it doesn't hamper the car's performance in autocrossing or at a drag strip vs. the 5 speed it came with because you never hit 5th gear in those situations (however I could gain an advantage if I were to find a close-ratio 5 speed...both my 4 spd and 5spd are wide-ratio models). On the highway, or maybe on a road course where you might run out of gear with a 4 speed, then the 5th gear might start mattering. I'd go with the U20 so long as it won't cost an arm and a leg to get the rest of the parts needed to rebuild it correctly (I hear timing gear components are ridiculous, but haven't looked myself...) When I finally "finish" my Z for a while, I hope to put a KA24DE into a Roadster. Should put out at least the power of a Solex U20 right out of the box, and hopefully I will retain fuel injection to boot. We'll see if it ever comes to pass. Good luck with whatever you decide to do!

[Minh]

Go U20!!! Sell the R16 motor and buy a used 5-speed tranny somehow.

SWAP!!!! Sell both the R16 and U20.

How soon do want to running is real issue. With R16 you can guesstimate how long it is going to take. With disasembled U20 with no 5-speed (depending on condition) it might take longer and cost you a bit more. I am in the same boat. I have just bought a complete non-op 68 R16 yesterday, yet I have resto project with a 69-U20 with a disassembled motor with new and used engine parts in a boxes.

I am opting the U20 for the 69. Just becuase its an original U20.

My 68 R16, I am either parting out, selling or swapping the R16 with a VG-30. I just had a whole 87 300ZX parting out for $300 this week. The thing had a blown head gasket and 275,000 miles. Very tempting to dump another few hundred and another non-operable vessel on my driveway.

But the idea of having 2 simultaneous project cars id not bode well knowing it will not going wll with my wife. Further, it will put me over the budget buget my wife and I agreed upon.


However, if cost and readily available parts is an issue Go R16 or Swap. The U20 is highly sought after and loathed becuase of its rarity. Engine and tranny parts will noticeably only get more scarce as each decade goes by. More after market product are available for the R16 (i.e. Weber carbs and manifolds) just go to any corner auto part store and look up trivial things. They will have SPL311 items than SRL311. The U20 is for diehard Roadster enthusiast who decidely come to terms with the pitfalls of owning one.

Good luck. I hope to have my U20 running soon.

[spl310]

Something that I wonder about is why so many folks put 4 cylinders in. I have seen a few VG30s, and two Chevy V6's, but not much on V8 motors. I have heard rumors of V8 powered cars , but have yet to see one - either in pics or in person.

If you are going to chop the car to put in more power, put in something that will get it noticed. A 302 Ford is cheap. Aluminum heads, intake, water pump and tube headers drop the weight considerably. You don't have to build a radical motor to make it a screamer . A stock 4bbl 289 with the restrictive iron intake, restrictive cast iron exhaust, choked down stock exhaust and a puny carb (not to mention the same cam as the 2bbl model) put out 225 horsepower. The hipo version put out 271. The shelby version (basically an intake/header swap) 306hp. Parts are cheap, and they are a compact design. Much narrower than the Chevy v8 and a LOT lighter too.

Add to the small block the T5 5 speed and you have a really lively package - a Japanese Tiger or Cobra.

If anyone has pics of a small block Ford installed in a Roadster, I would LOVE to see it and correspond with you and/or the builder of the car.

Sid
(anyone need any roadster bits? I need to clean out the garage!!)

[70MTroadster]

Hey Sid,

I bead blasted the fuel filler tube you sent me, painted it and installed it the other day. It works perfectly with the lockable gas cap I bought. Thanks a million for helping me out.

Which leads me to my next question; you say you need to clean out the garage. Got a set of choke cables in excellent condition for my 70 1600? How about a hand throttle cable?

RE; Ford V8's. Anybody know what a 289 or 302 weighs? Or what the R16/U20 engines weigh? I put a 225 HP 289 in an Austin Healey 3000 years ago and it was a screamer with an automatic trans behind it, but I never followed through and put in an "overdrive" 5 speed to see how it would go on the top end. 110 mph and she was tached out. But boy would it get there in a hurry. A lot of kids were sure suprised..

Scott

[spl310]

Scott,

Glad to hear that the part helped you out!

I will look to see if I have the cables you are looking for. I am sure that I don't have the long hand throttle cable, but I may have a short hand throttle and a good choke cable. I will see...

The R16/U20 are supposed to weigh in the 350lb range. According to a Street Rod manual I found, a small block Chevy weighs 750lbs and a small block Ford weighs 450lbs. With aluminum heads, an aluminum intake, headers and an aluminum water pump, the Ford gets even lighter. Makes for a pretty attractive proposition...

Sid

[TR]

Swaps: I have seen pictures of a V8 in the roadster engine bay, a lot of stuff crammed into a small space! The way the headers leave the engine makes it a very wide swap with a lot of frame and body modification necessary...The torque from the V8 with the weight of the car makes for some real tire burning possibilities. The weight of a V8 would really hold the front end down, even an all aluminum one.

I have also seen pictures of a VG30 conversion. It is claimed that this conversion can be performed without any frame mods, only intake and exhaust. That is an interesting proposition.

Another popular conversion is the SR20. This is a very light package with 150HP. It is a smaller engine with less torque, but still way more torque than the chassis/weight can apply to the road. Light frame modifications are necessary. This conversion weighs less than the stock setup and is modern power.

I, of course, am partial to the SR20DET conversion. Same as the SR20 but includes a turbo. This setup puts out 200HP and can be tweaked to put out rediculous numbers. I am guessing that weight will be about the same as stock when you add the turbo and intercooler items.

My two cents, TR

[DatsunBucky]

According to my handy-dandy Service Manual, the R16 engine weighs in at 155kg, or 341.7 lbs; is 25" long, 25.6" wide and 24.5" tall. So...Steve!! You win the pot! You came closest to the actual weight according to the manual.

BTW, I just LOVE the wording in this thing! Straight out of Japanese into Engritch! Instructions like (carb section) "Do not bend the jet needle underside the suction piston." and (adjusting points) "The vacuum type timing advancer is functioning properly, can be determined by the inspection pointer located at the diaphragm if, as the engine is being run, this pointer moves when the engine speed is suddenly changed, the advancer is satisfactory."

(steering) "When replacing steering column, reverse the removal procedure, but care should be excercised to see that at the steering column end insert lock bolt the fixed position which fittable hole to the universal joint." (double )

Just one more! Gotta have one more!

(back in carb section) "On the top of the suction piston, load of the venturi down flow is transmitted through the suction hole and the underside of it passes to the open air through the air hole and the air cleaner."

Gotta love it.

There was one (which I now cannot find) that when I read it, I must have looked like a dog listening to a high-pitched sound. "Maybe if I tilt my head just so, I can understa...no, that doesn't work, either. It still doesn't make any sense."

I bought the book in the early 70s when I started working on the car. It has parts numbers, but a lot of the ones I needed at the time had already been replaced by newer numbers.

Anyway, I'm always glad to share anything I can, with whoever.

Bucky

[70MTroadster]

I posted a reply and posed a question as to the weights/dimensions of the R engines and then several days later realized that I too own a Clymer Service Manual for the R16-U20 engines and the answers to my questions were probably in there. Of course they were.

You're right on about the direct translation from Jap0neze to Engrish! What great entertainment.

The very next thing I need to do is pick up the flex hose that goes from the hard line to the clutch slave cylinder as my clutch master has black milky crap in it now after driving for a bit. I rebuilt the master and the slave is brand new, so it must be in the flex line.

My brakes are working dandy but the fluid is taking on a redish, rusty color, so I will bleed them again to help flush out the crap and then start saving up for the Volvo front brake conversion and/or whatever else comes next concerning the brakes.

Tech questions; I picked up a used 5 speed from a late 69 2000 that has been sitting for 20 years. Is there any way at all to know if it is any good syncro-wise, etc. short of swapping it into my 1600 and seeing if it shifts well? I suppose at a minimum I would tear it down and put in new seals/gaskets and possibly some Amsoil synthetic gear oil.....I did this to the dogleg 5 speed I put in my 510 and it sure shifts slick...

scott

[DatsunBucky]

From the owner's manual for a '67:

gear / 5-sp (SRL) / 4-sp (SPL)

1 / 2.957 / 3.382
2 / 1.858 / 2.013
3 / 1.311 / 1.312
4 / 1.000 / 1.000
5 / 0.852 / ------

So, other than the addition of a 5th gear, it appears the 5-sp is a little closer ratio in 1st and 2nd (3rd is really just a tie).

But, a narrower torque band means that any given engine needs more gears to stay in the power band, and therefore conversely, more torque needs fewer gears. The Bob Sharp book has the same ratios for the 5-speed. I haven't come across any numbers of a close ratio 5-speed.

Scott-as far as being able to tell about the synchros, I am not aware of any external tests other than what you had in mind. In my autocross R16, I was forever replacing the 2nd gear synchro. I remember reading about some synchros being easier to defeat than "Superman taking on the bad guys." I don't remember the circumstances, just the quote itself.

Kinda like:

"When in danger
Or in doubt,
Run in circles
Scream and shout."

Bucky