Datsun Roadster Forum-311s.org

That is a servo transmission. The Warner has brass rings.
Dave

david premo wrote: Mon Nov 06, 2023 1:30 am That is a servo transmission. The Warner has brass rings.
Dave

Fair enough! I got caught up looking at geometry and wasn't paying attention to materials. Still leaning toward just installing as is for now, risk being I have to pull the engine if the syncros are bad enough. Engine overall seems lightly used so I think its low risk.

That transmission is very easy to rebuild, at minimum take off the bottom cover and check the counter shaft for play.
Dave

What's the old saying... "If it ain't broke don't fix it"? Yes, try the fluid leak test first on the valves and see what's what. Heads are not hard to disassemble with a little understanding and the right tool... for the U20 you need a C-shaped valve spring compressor and I prefer those over the type that grab the spring and screw tight to compression the spring, but that version can be used on an R head. Anyway, you compress the spring to expose the (2) keepers and fish them out with a small pen-style magnet, then release the clamp and off comes the spring. Now the valve will push out of the head. With the valve pushed down a bit in the guide (like it's being opened by the cam) wiggle the valve to see how much play there is (shouldn't be much), then remove the valve and inspect the valve stem with your fingers for a bump/wear and look at the sealing edges of the valve head... there should still be a flat sealing surface and the edge of the valve should not be sharp. After you clean up the valves (number each one), lapping the valves is not hard and involves using a suction cup on a wooden dowel and some lapping compound, attaching the cup to the bottom of the valve, applying a small amount of compound (be careful to keep the valve stems clean of any compound as it can gall the valve guides, and lube them with WD40 or similar) then inserting the valve into the head and pushing down with light force while rolling the dowel in your hands back and forth like you're trying to start a fire with wood sticks (there are videos on YouTube). Do this several times, lifting the valve off the seat and pushing back down again while you are rolling until the seat and the valve are a uniform color and don't show any high or low spots when you wipe off the excess compound. Assuming the seats etc are still good this will clean up the surface and make for a better seal. Reassembly is the reverse. I would replace seals but I'm not familiar with R head seals but I'm sure they are no big deal. Hope this helps.

Suggest you Do It Right The First Time. Your outcome will be far less frustrating and much better in the long run.


Take the head to a good machine shop and tell them:

1. Please wash/ clean / inspect the head
2. Please inspect all valve and guides
3. Please verify the head is flat to .001-.0015” on the head gasket surface
4. Please verify the head is flat too .010” on the valve cover side
5. *****Please do NOT surface the head yet, instead provide a report on what it needs and how flat it is.*****

The reason for 5. is some machine shops are "surface happy" and will take .030" off the head before any discussion and ruin it.

If the head is flat, great. If it is out a few thousandths it can be minimally surfaced.

If it is out more than .020, it really needs to be straightened before surfacing -it will ruin it just to cut it off with a surfacing machine.
(And the top will remain bent)

IF all is good, have it pressure tested BEFORE surfacing and VJ.

Believe me, Dorking around hand lapping a messed up (or cracked) head is a frustrating silly waste of time!


Also the "if it ain't broke" advice definitely doesn't apply to roadster 4 speeds. Dave's advice is spot on. AT LEAST check the counter gear shaft and bearings.....if/when those fail, (and they ALL will fail eventually) they will wreck the rest of the transmission. It is an easy fix before a catastrophic failure. If you ignore/let it go you will wish you didn't. 5-speeds don't have this issue. jt

Agreed. My advice was based on not wanting to spend much money on a motor that is likely to be replaced in the near term...

Learning and investigating is not "dorking around" or a waste of time... some people like to do as much as they can on their own and learn during the process... that's part of the fun. It was my understanding from reading the original posts that this is an effort to get an otherwise running engine checked over, and the only reason the head was pulled was because he thought he got water in the cylinders while pressure washing it, not that there were known issues. While it's out, freshening it up the seats and valves won't hurt anything and will give some idea of what shape it's in so he can decide what money he wants to spend on it . Also never suggested to not investigate possible problems, so please follow sage advice to inspect the 4 speed... I have no history with them and limited experience with the 5 speed.

Regarding any advice or suggestions I ever give anyone, take it or leave it! No ego threat to me here, I'm just trying to help and have no skin in the game...

Checked the counter gear shaft, seems tight. Are there tolerances listed anywhere for what it should be?
I’m pretty sure the head was resurfaced at some point. Anyone know how thick it was from the factory? Or some other way I can confirm. I’m going to take it in to work and check flatness.

There should be zero axial deflection of the counter gear. If you can move it axially at all, the shaft or bearing has failed. (The best way to check it is to pull out the shaft and inspect the wearing surfaces)

JT68 wrote: Tue Nov 07, 2023 4:30 am There should be zero axial deflection of the counter gear. If you can move it axially at all, the shaft or bearing has failed. (The best way to check it is to pull out the shaft and inspect the wearing surfaces)

Should be good to go then. There was some rotational play but I couldn't get any axial or side movement out of it. Just wanted to make sure I didn't need to go get a dial indicator or something...

Shifting topics - Water/coolant (I think mostly water though) has been left in the block for the last 5 years, its got that bright rusty color. Advice on sorting that out? I'm thinking remove the side freeze plugs (35mm?) and go to town with a pressure washer. Then refill the system with the evaporust thermocure product for a while.

Been working on the carbs, splurged and bought myself a tiny ultrasonic cleaner, one carb I used diluted Krud Kutter, the other I used diluted Simple Green pro HD the purple stuff. Both worked well, soft bristle brush was able to get everything off. Krud Kutter isn’t fully safe with aluminum, I ran the parts for 30 mins at 70C and when they came out they were starting to darken and had some pearlescent sheen which seemed like an oxide layer. SG pro HD just left beautiful shiny aluminum, though it did start some white crystal like growth in the cadmium plated parts so that’s a thing. Forgot to get pics of that…

Before cleaning:
Krud Kutter carb reassembled:
Simple green pro hd carb waiting for reassembly:
This weekend was spent mostly by running up to Tyler to get a parts car/dash donor for cheap. It’s mostly complete from what I can tell, pretty sure it’s a 67.5 car?

I’ve found evidence of it being split through the cab a little behind the shifter opening, so it’s probably 2 different cars. Even then the rear quarters are pretty banged up, I went to town on the filler because I wanted to see what was there. I guess someone had fun in it at least! Haha Floorboards are mostly rusted out. Surprisingly the rockers and fenders seem pretty good, I didn’t see evidence of rust and very little filler when I was chiseling it out of other places. It’s probably salvageable by someone who’s willing to put in the effort but I’m not that someone. It’ll be a bit before I start cutting it up, reach out if you you’re interested in it whole, we can talk. Otherwise I’ll start posting parts in the classifieds as I get to them.

Experimenting with Evapo-Rust I dumped the heavily rusted fasteners and the water pump pulley in to soak, will update in a day or two. It’s worked wonders on other parts so we’ll see how it does with this level of rust!

Those carbs turned out nice! What ultrasonic cleaner did you get? I've been wanting one for a while now and just haven't splurged yet... however, I'm liking the idea of it more and more.
Also, did you use a kit for the carbs for gaskets and seals? If so, where did you get it from if you don't mind me asking.

sfyks870 wrote: Sun Nov 12, 2023 7:50 pm Those carbs turned out nice! What ultrasonic cleaner did you get? I've been wanting one for a while now and just haven't splurged yet... however, I'm liking the idea of it more and more.
Also, did you use a kit for the carbs for gaskets and seals? If so, where did you get it from if you don't mind me asking.

I got the Creworks 3L but should have gotten a 4L or 5L I think, it’s small enough that I couldn’t fully submerge the main body, the last half inch of the casting was sticking out when I put it in upside down even after overfilling it a bit. https://www.ebay.com/itm/265432496329 heater is kinda slow but it gets up to temp eventually. I recommend starting with hot tap water to speed up the process. I’m excited to have it, it’s going to make cleaning things way way easier!

I got a gasket kit and new screws from Sin City Datsun, should have gotten new floats and float valves while I was at it… Good quality, and I’m a few towns over so fast shipping too! https://sincitydatsuns.com/store/p314/A ... t_kit.html they are having black Friday sale on Nov 17-18 15% off…

Was able to get a bit of work done on things tonight!

Got the simple green carb reassembled, shot a very poor timelapse that isn’t worth posting but here’s a screenshot from it. The piston in this one drops much faster than the other. Not sure where the discrepancy is but I’m pretty sure it’s supposed to drop fast so I need to work on the other one some more.
I also broke down and cleaned the carbon deposits off the inside of the intake manifold and ended up working on the petcock some, finally got it turning. I’m not clear on what it’s purpose is but figured it should operate correctly! PO had turned it so far past the stop that it bound up, I think I got it sorted. Anyone want to clue me in on what it’s used for? (Don’t worry, hose clamps are on the list)
Got started on filling in the rusted out bracket that was between the thermostat and filler neck. Not sure how well this JB Weld goop will adhere, but I don’t think it needs much since it’ll be clamped in with gaskets and such. I definitely didn’t leave that much built up either, started in on it and then figured I needed a before pic to show how bad it was haha. I’m not sure what it’s for yet but figure it’ll make sense when I start putting the engine back in the car.
24hr preview of the parts I put in the Evapo-Rust. I can’t believe no one told me about this stuff earlier in life, it’s awesome! I don’t plan on using any of the bolts, but wanted to see how well it would do so I know what to expect for other things.
Cleaned up the donor chassis enough to get the vin/serial, SPL311-14346. Which doesn’t match the title I got.
And finally, I cleaned up my first interior component! Yay!
I’m really looking forward to having this put together and going for a drive. Shooting for January, the holidays aren’t going to leave much time for working on things.

Preping to troubleshoot the piston drop speed differences on my carbs, found some additional handy videos that weren't in the tech section (at least I don't remember them being in there).

Not directly discussing our Hitatchi carbs but helpful info on SU style carburetors. Very in depth: https://www.youtube.com/watch?v=e15QlVLjJiU also, its been mentioned before but this SU needle size guide site is handy: http://mintylamb.co.uk/suneedle/

Piston drop testing (I'd remove the needles personally):https://youtu.be/IfU47Oqq9wA?si=iqDLZ48IkRefC765&t=105 https://www.youtube.com/watch?v=8GanhEEcCB8

Also found a handy guide with diagrams thats for a similar style SU carb https://sucarb.co.uk/technical-carburet ... ettings-hs

Taka on instagram did a walkthrough of the hitachi carbs: https://www.instagram.com/reel/CvNfkRht ... k0MDhjYg==

Mixed feelings after working on things tonight…

Started off pretty well by pulling some expansion plugs and washing gunk out of the block! PO left water in the block for the 5 years he had it disassembled, I guess he didn’t know about the drain in the block? Here's what it looked like when I started :
And here’s the video of the first gunk out of the block:
[youtube]https://youtu.be/HGpklk87Hjs?si=UJhoIM5h-O0jgoHD[/youtube] (can’t get the video to imbed, which tag am I supposed to use? Is it because I’m on my phone?)


After lots of rinsing, poking around with a coat hangar (and deciding half way through that taping the top of the block was a good idea - Gorilla tape for future reference) it’s currently at this point:
Still some cleanup needed on the cylinder walls, I think I’m going to seal up the expansion holes with tape or maybe some of the rubber expansion plugs and then soak the while thing in vinegar for a few days. There’s also some bridging between cylinders, I’m not sure if it’s casting material or scale that’s just really wedged in place. I think the vinegar soak will clarify that some.

Once I’d gotten things dried off I chased all the holes for the head bolts, looooots of gunk in the bottoms, like seriously, where did this all come from?!
I also chased the threads on the head bolts, and this is where the night started getting rough. All the bolts bound up at some point on the die, after examining them all a bit I’m pretty sure the threads have yielded to some extent on all of them. So I’ll need new bolts or studs… Disappointing since I’m really just doing this so I can get it registered with a bonded title here in Tx, and was hoping to get some days of driving it before I started in on engine swap and real restoration/mod. So now spending more money on an engine I’m not using for long.

I did a quick visual check of the distributor timing and it looks good, it could be off by a tooth I guess but I don’t think I can tell that at this stage?

I then moved on to some clearance checks between head and pistons because the head seemed really thin. I put some playdough on the pistons and snugged the head down with a few of the bolts, found a hole that needs more work, yay! I didn’t install the head gasket because I figured there should be at least that much clearance?

Anyway, I turned the engine over slowly and hit a point where it wouldn’t turn any further no matter how much I tried. So I backed the head bolts off a few turns thinking it could be compression since I didn’t have much leverage and I don’t have the rocker arms installed. That didn’t end up helping so I took the head off haha. This is what I found on the piston side
I didn’t get a pic of the head but there was more dough mashed on #3. Looked an awful lot like contact so i cleaned up the playdough and just set the head on top of the block to see what happened. Got contact on both pairs of cylinders! After that I went ahead and measured the head thickness, which I should have done first! It measures out at about 3.11” so .078” lower than minimum allowable according to: viewtopic.php?p=130672#p84118

I made a very unscientific set of shims out of folded paper towels, measured out to about .045” with the calipers but I suspect was closer to .060” since the head didn’t apply as much pressure. Didn’t get any contact with that setup. I’m bummed, already ordered a standard head gasket but now at the very least I need to get a thicker one. Or find a different head (donor car might save me here). Or work on the dish in this head (anyone know how much material is there before I hit water passages?)

I decided to call it quits at that point, now I’m drowning my troubles in good Scotch, ending the night on something nice!



PS. Yesterday was a good day, I got the carbs all back together and happy (except for the overflow tubes) Turned out the oxidation from the Krud Kutter cleaned piston/dome was enough to slow the piston significantly. I guess if you need to add back material that’s a method! I did some work with a scotchbright pad and now both pistons are almost perfectly in sync.