Datsun Roadster Forum-311s.org

Hi all,
I've found a rebuilt U20 near me for $900. Just needs a water pump, flywheel and starter.
Think it's worth swapping it for my R16?

Jason

Having been in a sort of similar situation, here's my two bits worth....
I'm assuming your engine runs well, idles smoothly, etc.
If the engine was professionaly rebuilt and there is documentation regarding it's condition, especially the valve train, I'd consider it. If it was not done by someone you have reason to be confident in, I would have serious concern.
On the surface, such a trade sounds like a good thing. After all, more displacement and an OHC has got to be better, right? In reality, you might be trading a good running car for one that will be costly to get to the point you're at (that is, a good running reliable drivetrain).
One thing that would sweeten the deal is if it included the rest of the drive train (5 speed, clutch, spacer plate, driveshaft and crossmember). If that was part of the deal, I'd be all over it.
Dan

You will love the U20, but be aware that some parts are more expensive than R16s, and your rebuild may or may not have those expensive parts already replaced or in decent used condition (namely the timing gears/chains/tensioners). We can guide you some on what to look for regarding those gears, inspect before you buy!!! Also, you will likely want the 5speed which requires the U20 drive shaft, slightly different trans mount or modification, and the U20 clutch plate (has anyone run a 4speed on a U20?). If you go this route, get an aluminum flywheel or a lightened one in my opinion, and a gear reduction starter would be recommended. Also, what kind of condition are the carbs in? The header/exhaust manifold may not bolt up direct to your exhaust so consider that possible expense.

Clutch disc is the same, the pressure plate is different. You could use your flywheel and possibly the starter. You will have to modify your cooling system or get a 2000 radiator.

Good price. I have a few spare radiators and a fly wheel. Has some bad teeth on the ring gear.
Have some used u20 pressure plates in VGC.

If you do decide to swap. Send me a PM

I would buy it and hold on to it. build a test stand and set it up and run her.

Than at some future point you can either install or sell. For the money, there are lots better up grades......new windshield is one that is often forgotten.

fj20spl311 wrote:I would buy it and hold on to it. build a test stand and set it up and run her.

Than at some future point you can either install or sell. For the money, there are lots better up grades......new windshield is one that is often forgotten.

You can't even get close to buying the parts to refresh a U20 for that money, much less rebuild.. So if you find a way to believe it's really been well rebuilt, it's one heck of a bargain.. I think what Phil says makes a lot of sense..

All,
Thank you all, this is great input. The motor looks pretty darn complete and good. It's a 70' motor with new rings, valve job, rod and main bearing, seals and timing chain. Rebuilt carbs and new header.

To answer Dan's earlier question, my R16 has been sitting for 21 years. I'm in the process of getting everything hooked back up to try and get it started. So I really don't know how well it will run.

My 1600 has a 4 speed.





Jason

By the way, Garm used a 4 speed behind a U20..

Do It man Do it !!!!!!!!

RCMike wrote:By the way, Garm used a 4 speed behind a U20..

Did this in 1990 with a yellow 68. It works great, very fun to drive, but 2 things to consider:

The 4-speed counter gear shaft and bearings are typically worn out in mid-mileage 4-speed even from use behind an r16. It is an easy, but not super cheap repair. If you put a 2L in with a compromised 4sp counter shaft and drive it even semi-hard, it will destroy that shaft in no time. WHEN (not if) the counter gear shaft wears badly enough, the counter gear self destructs and effectively trashes the 4-speed. Fix it first if you use a 4-speed since the additional torque of the 2L just compounds the problem.

1st gear in the 4sp is a low ratio, so with a 2L it is over almost immediately. Consider swapping in a 3.7 rear with the 4-speed - really helps on the highway too. Even with a 3.7, in 4th gear a 2L will take it all the way to redline! With a 3.9/4speed/2L it is very zippy (but annoying on a long trip as with a stock 1600)

Thanks for the input everyone!
Unfortunately someone else beat me to it. They picked it up 30 minutes after my initial contact.

Oh well.

Jt68, very use for the future!

assuming it's just the long block... what is needed to complete an u20 swap?

That's the problem with posting here. Someone will get it if it is good. All legal though LOL

Linda