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1966 404 Coupé Injection Restoration

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I should have clarified - I knew the gap was adjusted depending on if it was running Nitrous or Forced Induction / Boost, but didn't realize there were differences between street spec and high performance spec engines with no power adders - But sure enough:

For a street engine, multiplying your bore size by 0.004in will give you the top ring gap you are looking for.

  • 004 x 4.00in bore = 0.016 inch ring gap

For high performance engines, the multiplier changes to add more clearance, but the math stays the same:

  • Modified or Nitrous Oxide - 0.005in x 4.00in bore = 0.020 inch ring gap
  • High Performance Racing - .0055in x 4.00in bore = 0.022 inch ring gap
  • Racing with Nitrous/Turbo - 0.006in x 4.00in bore = 0.024 inch ring gap
  • Racing Blower/Supercharger - 0.007 x 4.00in bore = 0.028 inch ring gap

For the second ring, the process is the same, but with a slightly different gap, based on application:

  • Street - 0.005in x bore size
  • Modified or Nitrous Oxide - 0.0055in x bore size
  • High Performance Racing - 0.0053in x bore size
  • Racing with Nitrous/Turbo - 0.0057in x bore size
  • Racing Blower/Supercharger - 0.0063in x bore size

The reason for these variable specifications is that different types of engines put radically different heat and pressure loads on the ring package.

Taken from this excellent article:  http://blog.wiseco.com/everything-you-need-to-know-about-ring-gap

Those being examples of course, ring maker specs would be what you followed rather than these numbers, but was still good info.


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Yeah I will be running the car reasonably hard on highway drives, like at 120 km/h up the 8% gradients on the Coquihalla at high sustained RPM.

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Yesterday I got the last batch of plating work back from Victoria.  The job was good on what they returned but somehow they managed to lose the crankshaft pulley (I have a spare) and a small clamp for the injection system piping (I likely have a spare and if not it'd be easy to fabricate).

Anyway, I have two complete sets of steel fuel lines and both were plated in copper.  The fittings are copper so I thought it would be the best way to protect the steel and would help the fittings too.  One set was used on a running engine as little as 14 years ago (the car's) and the other from one that was last run in 1990 (our former 404 sedan's).  As it turned out, I should have pigged them out before plating because when I got them back I realized 6 of the 8 were blocked - I could not blow air through them.  So one by one I rammed a very stiff wire up each tube and some rusty gasoline sludge and varnish came out when I squirted some Varsol through them.  I'll do it one more time just to get the last bits out and then choose the best 4 for the car.  I also have one NOS tube, which is like a very dark patina copper colour.  I would not want to have the beautifully cleaned injectors fouled up by whatever might have been in these tubes!  Even though I have 18 injectors.....

I got the sump washers and bolts plated, valve cover bolts, timing cover bolts, some other bolts for the throttle body etc.  Also the trunk latch loop.  And the welded heater tube was redone in zinc too.


plated parts Oct 2020-02.jpg

Injection lines first cleaning.jpg

pigging out the lines.jpg

Plated parts Oct 2020-01.jpg

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They're cleaned inside now and ready to go - the set that's upside down in the lower photo will be my spare and the set that is upside down in the top photo and right side up in the lower one will be used on the car.  You can see the pitting from the rust, which I rather like as it's a reminder that these are original parts.

bottom side plated fuel lines.jpg

top side plated fuel lines.jpg

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Are the injectors new?  And have they been flow matched at all?  Or is it just opening pressures that need to be matched?

LOVE the copper coated lines too BTW - will you let them tarnish and patina or keep them shiny?


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If you read back a few pages you will find that there are 6 new injectors, 8 good used ones and 4 more OK ones.  They don't need to be flow matched - the injection pump pistons determine the amount injected.  They were tested in England at a specialist and will be pressure matched.

Tarnish within reason - if they go green I'll shine them up a bit.

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  • 2 weeks later...

Not a lot new to report other than the wait continues for the new intake valves (slow mail!) but today I took the C3 gearbox into Victoria Transmission for the long-overdue bearing replacement and internal inspection.  The older fellow who will be rebuilding it did the same job for my friend Tim Bowles' 404 Coupé Injection about 20 or 25 years ago.  I have one special tool for it (depth gauge) and dropped off the reprint of the gearbox chapter of the workshop manual.

C3 at Victoria Transmission.jpg

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Coolest 7" headlights ever......tempted.  Even though I have Z-Beams in the 404C now.  Likely I'll pass.  I used to own some in less perfect condition...sold them for more than these cost.


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Look again, these are SAE mount Cibié Biode replicas, each one has two H-1 bulbs and two separate reflectors inside.

The seller confirmed today that they are replicas, but they seem to be very good ones.

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I finally put the front brake hose fittings that Jean-Marc Faivre sent me from Cheminot France a while back on the car after a good cleaning.

Then I assembled the water pump with a pulley from a 504 and a later type nylon 6 bladed can in place of the 3 bladed original.  Set the air gap provisionally too.

Then I checked the oil pump/distributor drive shaft and damn it, it's worn near the bottom.  So I'm going to buy a new old stock one from Dean Hunter in England.  I'm also getting a couple of springs for the carbon brush of the electromagnetic fan.

I also found the new intake valves I meant to bring to the engine shop originally.  Only three are original and one is probably aftermarket so that is why I ordered another set....

brake hose adaptor front.jpg

brake hose adaptors from J-M Faivre.jpg

brake hose LF.jpg

brake hose RF.jpg

Valves first set.jpg

water pump assembled.jpg

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Eldest daughter Jennifer brought the rebuilt gearbox home.  Personalized note on the top cover!

If you're wondering, the Nardi shifter can only be bolted on from inside the cabin, once the gearbox is in position below the car.  There is no other way to install it.  So I leave the corrugated plastic in place until I'm ready to install the shifter.

The bearing near the centre of the closeup photo is the main input shaft bearing, SKF 6207N.  This is the one that generally gets noisy in the 404 C3 gearbox as it ages, with the engine idling and clutch pedal released (input shaft spinning).  Even loose in my hand it made a significant noise, which none of the others did.

I'll see about installing it tomorrow after I fashion some sort of front support out of a steel strap I bought, to simulate the factory tool, and then put the shifter on....

C3 rebuilt.jpg

Used gearbox bearings.jpg

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What was supposed to be a quick removal and cleaning of the clutch release bearing shaft and the installation of new bushings and carbon bearing ended up being a 5 hour nightmare.
The clutch release shaft is usually easy to remove with the steps being to remove the bolt from the fork (the head is behind, facing the gearbox), push the release bearing fork along the shaft against the spring, release the circlip that holds the fork in a precise location on the shaft, take the circlip off the small end of the shaft and gently tap until it slides off the (splined) fork and then you're done.
Well, the forged aluminum fork was seized to the shaft at a certain point - just would not budge. I decided to drill it full of holes along the shaft to hopefully make it release (destroying it in the process of course) and even full of continuous holes it still was a bear to drive out. In the process, the boss on the bell housing that supports one of the bushings broke a chunk off.
So I went out to the shed to retrieve a spare gearbox, brought it up to the garage, took its bell housing off, removed the cutch shaft without the slightest problem (GRRRR at the first one!), whipped the bell housing off the rebuilt gearbox and cleaned the other one up. That took a while. Then I selected the best clutch release bearing shaft I have and prepared it.
The rest of the job was easy but painstaking, removing the Permatex Grey from the rebuilt gearbox sealing faces and the other bell housing, cleaning them with acetone and then resealing. A brief moment of almost panic ensued when the input shaft would not turn but I figured the shifter forks had just gone into an implausible position (remember, the shifter is not on the gearbox yet) and yes, that was it.
So I was unable to make the tool to support the front of the gearbox, much less, install it!
The little tube on the upper part of the release fork is for oiling the carbon bearing from above. Regular maintenance....

New release bearing installed.jpg

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I received the new intake valves, SASIC brand, this afternoon in the mail.  They look pretty much exactly like the OE valves.  I'll run them down to the engine shop next Monday, or sooner if the shop needs them before then.

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