I was giving my 404 some love today, chasing down a poor-running/power issue. While I was checking the tightness of the carb (all the nuts were a tiny bit loose, but not too bad) the wrench slipped off snapped off the right-side mixture screw. Flush. With. The. Carb. The only way I can think of to fix it is to remove the carb and MIG-blob a nut on and hope it comes out - which it should. I hope.
Tune-up fun - breaking stuff
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I changed the plugs, which was also an adventure. The first one I tried - closest to the rear - fought me coming out but didn't seem to take any head material with it; the new plug went in without any drama. The next one came out like normally, but when I put the new one in finger tight, it wouldn't take any torque. Ok, we'll come back to that one. The rest of them came and went with no issues other than the challenge of getting the front-most plug threaded in. I almost started to cross-thread it, felt it going in wrong, and started over.
After I got the last one in, I fired it up. It started right up and idled nicely. I hit the gas and BLAM! The loose plug let go, sounding like a .22 in my face; oops, forgot about that one. I got a repair kit from Autozone and got it patched up. I know it's not optimal, but it's the best I can do under the circumstances.
After I got the last one in, I fired it up. It started right up and idled nicely. I hit the gas and BLAM! The loose plug let go, sounding like a .22 in my face; oops, forgot about that one. I got a repair kit from Autozone and got it patched up. I know it's not optimal, but it's the best I can do under the circumstances.
Attachments
It shouldn't take much force to remove the idle mixture screw. Last time I fixed that we used a dremel with a mini cut off wheel. Scored the center in a line, and used a small screw driver to screw it out. Pretty easy as normally they are not tight. I've also managed to get one out with a dental pick just pushing/pulling on the ridge left at the break.
A note on the cylinder heads. "Short Reach" and "Long Reach" are a term that all 404 owners should confirm. Using a long reach plug on a short reach head is a surefire way to rip out the threads in the head. The long reach plug installed in a short reach head will stick down further than the threads of the head and the carbon will build up on the threads. When you unscrew it, that carbon can do a number on the threads in the head.
Did you use a timesert or helicoil for the repair?
Cheers,
Scott
A note on the cylinder heads. "Short Reach" and "Long Reach" are a term that all 404 owners should confirm. Using a long reach plug on a short reach head is a surefire way to rip out the threads in the head. The long reach plug installed in a short reach head will stick down further than the threads of the head and the carbon will build up on the threads. When you unscrew it, that carbon can do a number on the threads in the head.
Did you use a timesert or helicoil for the repair?
Cheers,
Scott
I've done something similar in the past.
Yes, the plugs I removed and the new ones I installed were both 'long reach' but I think I really need 'short reach'. You can probably see the damaged threads on the plugs towards the very tip. I didn't know that I was going to need one or the other when I ordered them.
The piece I used is more like a timesert, but is cheaper. There's a really beefy one I use in VW heads, but I'm out of them right now.
Also note how the front 3 plugs were burning great, but the back 3 - particularly the 4th one back - are horrible. The one black plug in the middle had a very iffy wire connection. I bought the parts to do the civilian ignition conversion, I just need to find the time to do it.
The truck runs a lot better now; I'm taking it to Euro Sunday tomorrow morning.
Did the heads with the deeper threads appear at the same time as the double row cam chains or is that totally unrelated?
I had two 1963 404s (at least that is what the paperwork said, who knows what the truth was) and they both had double row cam chains and deep threads.
Aside from an obvious visual inspection/measurement of the threads, is there anything else that would be an indicator of which head a 404 owner might have? Year, VIN specific?
Just curiosity.
I had two 1963 404s (at least that is what the paperwork said, who knows what the truth was) and they both had double row cam chains and deep threads.
Aside from an obvious visual inspection/measurement of the threads, is there anything else that would be an indicator of which head a 404 owner might have? Year, VIN specific?
Just curiosity.
In general with the 404 the short reach heads are the exception, not the rule. To be honest rarely if ever do I see a single row timing chain on the 404 M180. It is common for us to find the short reach heads are the ones with the complex valve train and the larger hump valve cover. I'll try and pull photo's out of the archive early this week and update this thread showing the difference. Tell me you have an original short wheelbase 404....and I'll bet it has short reach plugs.
Visual is usually acceptable. We are talking in laymans terms about the difference between a 13MM (1/2") and 19MM (3/4") plug reach. The plugs pictured in this thread are the more common 3/4" length. It's a bit hard to tell from the pictures, but my gut feeling was it looked like a pretty short reach on the head where the plug blew out. (Hence the suggestion to check.)
Bottom line, your plug threads should be flush with the inside of the head, anything longer and you run into problems destroying the threads on removal. Anything shorter and the engine will not run as well as the spark is too far recessed into the head.
Again, once checked it should be a non issue for the owner as both sizes of plug are available both in Shielded military configuration and in standard civilian configuration.
Cheers,
Scott
Visual is usually acceptable. We are talking in laymans terms about the difference between a 13MM (1/2") and 19MM (3/4") plug reach. The plugs pictured in this thread are the more common 3/4" length. It's a bit hard to tell from the pictures, but my gut feeling was it looked like a pretty short reach on the head where the plug blew out. (Hence the suggestion to check.)
Bottom line, your plug threads should be flush with the inside of the head, anything longer and you run into problems destroying the threads on removal. Anything shorter and the engine will not run as well as the spark is too far recessed into the head.
Again, once checked it should be a non issue for the owner as both sizes of plug are available both in Shielded military configuration and in standard civilian configuration.
Cheers,
Scott
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