Datsun Roadster Forum-311s.org

This is the official build thread of my new (to me) 1968 SPL311-21773.

I spent from 8am to 6pm yesterday working on getting the engine out and torn down for a rebuild. It was a long day, seeing as I have never, until this point, worked on a Roadster before.

I was very frustrated by the placement of the motor mount and header/carb nuts and bolts. In particular, those two large brass nuts that hold the bottom flange of the SU's on. In any case, about 6 hours later and covered with gobs of dirty grease, oil, and coolant, the engine was out:


The PO had the head rebuilt and it looks pretty nice. One less thing that I have to do I guess.


The engine supposedly had low compression on cylinders 1 and 2. The pistons and bores look very good with no scoring. This picture is after I used the ridge reamer to get rid of the top carbon build-up before popping the pistons out. This is how the engine sits right now, as I ran out of time.


One question: the car ran for a few minutes to put it onto the car trailer, and for a few minutes when I got it home. The PO put a brand new oil filter on it, but after removing the oil filter, there was no oil inside of it at all. Is this a sign of a bad oil pump? I've heard that oil pumps generally don't go bad on these. Is that true? I haven't removed the timing cover or oil pan yet, so I'm not sure what the lower end looks like right now.

And the journey begins !

2 and 3 look like they have some unusual scoring on them. If the oil filter was DRY, I'd be freaked, but if not, then it probably just drained back down into the oil pan. It would have made one heck of a racket if it wasn't working at all. While they are reliable, if I was rebuilding the engine, as you are, I would want to know the condition of all parts and would strongly consider replacing the Oil Pump at the same time. You can check the gears for wear, and I believe there are clearances that are listed in the manuals and can be checked.

A note, it is not necessary to remove the carbs and starter to pull/replace the motor, in fact you want all that on when you put it back in, specifically to avoid the problem with the lower carb nuts.

Good luck, looks like uou are moving right along!

The scoring is very light. Almost light enough that you can see it but it doesn't feel like much. I'm hoping the flex-hone that I got will get rid of it.

That motor looks pretty clean for just being pulled out
Might as well move the alt to the passenger side while you are at it.

RFR wrote:That motor looks pretty clean for just being pulled out
Might as well move the alt to the passenger side while you are at it.

Are the wires and stuff long enough, or do you have to extend them? What's the main purpose of relocating it?

notoptoy wrote:If the oil filter was DRY, I'd be freaked, but if not, then it probably just drained back down into the oil pan.

Bone dry. No oil whatsoever.

Also, what does this hose do? One end goes to the lower block, and the other end goes to a small bulkhead. From the bulkhead, there is a small steel line that goes into the manifold that all the brake lines go to. The hose is dry rotted underneath the spring.

Wow, that's really strange, how loud was it when running?
If there was no oil pressure at all, then I would suspect all the bearings are toasted.
Was there a "anti-drainback" tube in the oil filter - basically an aluminum tube that sticks up into the oil filter?
Perhaps the tube was wedged against the top of the filter, not allowing oil flow past that point?
Or the oil filter was wrong, and it was "reversed" in operation? I don't know, just grasping at straws here.
Definitely strange, as it looks like at least some oil was making it to the head.

Well, I found the exact same oil line on datsunparts...it's the oil pressure gauge line. But why does it go to the same aluminum manifold that the brake lines go to? Or is that just some sort of pass through "hub" for fluid lines?

It was a cheap STP oil filter (if that even matters, maybe the filter wasn't fitting right?), and there's no oil anti-drainback tube. Definitely a lot of oil under the valve cover when I took it off. It's stumping me too. The only oil on the filter was on the rubber seal. The car wasn't running that loud. I mean, it sounded about right for running on 2 cylinders and having a magnaflow muffler on it.

The car had TONS of exhaust smoke coming out of the PCV nipple on the valve cover. Where exactly does this amount of blow-by come from? Like, how does it enter the head underneath the valve cover. I looked to see where crankcase pressure enters the top of the head, but I can't find the location.

That would be your valve seals, though with that much blow-by your stems and guides may be shot. Either a bad head job, or the seals have dried up beyond usefulleness.

Mainer311 wrote:

RFR wrote:That motor looks pretty clean for just being pulled out
Might as well move the alt to the passenger side while you are at it.

Are the wires and stuff long enough, or do you have to extend them? What's the main purpose of relocating it?

You will have to extend the wires, that's a minor job.
The benefits are: the alt is easier to get to........it lasts longer because it is on the "cool" side...........you can also replace it with a self regulating higher amp alt such as the GM "single wire"

I think the only reason it was moved to that side was to facilitate the smog pump, on earlier cars it was always on the passenger side.

Mainer311 wrote:Well, I found the exact same oil line on datsunparts...it's the oil pressure gauge line. But why does it go to the same aluminum manifold that the brake lines go to? Or is that just some sort of pass through "hub" for fluid lines?

It should not. it should be connected at a hardline under the battery. hard line to the gauge.
the "hub" is a proportioning valve. For brake fluid only.

I think the "hub" you are referring to is a clip that holds the brake lines and all in place. If you carefully trace the line, it goes into the firewall and to the gauge.

On the engine, I blame Dave!!

This car just keeps getting more and more interesting. I'll have to re-follow the hard line to see where it goes again to make sure I'm not crazy.

The valve seals were replaced when the head was rebuilt recently. The head was rebuilt by a performance shop in Concord, NH. I wonder if they f*cked it up?