Just wondering what the people with Buick nailhead engines rate as the best carb to use. My 364 has been bored out to 0.40, am running a carter 2bbl on it. Bought it under the impression it was rebuilt, but the idle mixture screws are bolloxed, couldn't find any exact replacements. But i found some very similar ones the right length, that had more thread than the old ones, so had them machined up, they were the closest thing to the originals, but it still makes no difference to the engine idle, even if screwed all the way in the engine doesn't falter. The problem I am having is the engine seems to idle somewhat lumpy on the drivers side. Nice continuous rhythm coming from the passenger side tailpipe, and a rather irregular lumpy one coming out the driver side tailpipe. I'd like to at some point put a 3x2 set up of Stromberg 97's. But have no cash at the moment, so am looking for cheap alternatives. Any suggestion guys?
I wouldn't blame it all on one side of the carb. Each side if the carb feeds two cylinders on each side of the engine.could be plugs, wires, valves, points or vacuum leak.
There's a soft plug in the bottom of the manifold that's famous for leaks. Shoot some starter fluid under there while it idles - if engine picks up speed, you found it.
Is that the inlet manifold or exhaust? I'm guessing you mean that big round disc thing in the centre of the underneath of the inlet manifold. There was a pretty bad leak from the exhaust on that side, where the downpipe joined the header, but I fixed that. The engine is completely rebuilt, so new pistons, bearings, cam, lifters, rods, rockers, valves, valve guides, plugs, wires, cap, points, rotor, you name it etc. I thought maybe I had a vacuum leak from the inlet manifold, so have just recently pulled all that off, thoroughly cleaned it out, and treated it to a new pair of gaskets.
The soft plug closes up the exhaust crossover. A leak there should not produce a vacuum leak. a 2 x 3 setup will certainly look good but a 1 x 4 on a stock cast iron manifold is easier to tune and makes more ponies. The most available 2 x 3 Nailhead manifold, manufactured by Offenhauser, requires expensive, expensive porting work to match the flow potential of a stock cast iron manifold. Stock 364 1 x 4 manifolds show up on eBay from time to time and typically sell for less than $150. Nailheads like more CFM than other similar sized OHV V8s. A 700 CFM Edelbrock or Holley square bore should work just fine.
If you turn mixture screws all the way in... And nothing happens, fuel is come from somewhere else. Ie; high float Power valve Assuming that carb has a power valve And it opens at idle. Check your ignition timing. if its retarded the engine will have low vacuum. (Alowing valve to open and run rich). Try setting your timing with a vacuum guage. Hook up to manifold vac Start engine and let idle Advance distributor to highest vacuum reading possible (18 to 22 inches hg) then back off 2 inches and lock it down. This gets you close. Obviously setting timing with a light is standard. But if the chain is loose or the balancer has spun Your settings will be incorrect. A good compresion test static and RUNNING COMPRESION with throttle snaps, Can also rule out a lot of guessing I know it is rebuilt but.... Good luck.
This is all great advice thanks guys. It seems to run rich that's for sure. I set the timing up according to the workshop manual, i have since tinkered with turning the distributor, and although it does fire straight up from cold, i was wondering if the timing could still be slightly off. I'll get a light on it. Has a new set of cogs and timing chain, so that should be fine. Will also check the float as I've had the carb apart many times at that could well need adjusting. I was thinking maybe a 1x4 would be better, I always thought that little 2 barrel carter look weedy atop of that massive lump. i'm wondering if the Edlebrock 500 would fit the stock 4 barrel manifold, or if an adapter plate would be needed.
I have a stock 4 barrel manifold for the 364 if your interested.You would need an adapter to run the edlebrock which is easy to find.I may even have one.
I'm going to try a few things on the 2bbl carter first, like float adjustment, timing etc, just out of interest what would you want for the manifold? I'm in the U.K so I would imagine that shipping would be a fortune on something that weight.
The float did need some adjustment. It was coming up too high, don't know if I have adjusted it to the correct height. The workshop manual says to use a tool that I don't have, so I just looked at how the float looked in the picture, and matched that. It seem to help a little bit. The other thing I have noticed is when starting the car from cold, you get that normal white smoke from the ehaust while the car warms up, esspecially in the cold, well, it's only visable on the passenger side tail pipe, the drivers side is pumping out, with some slight irregulairity in the rythm, but the smoke isn't visable. However, both pipes will expelle moisture sometimes when warming up. As is normal. Whether it makes a difference or not, but the Carter has an automatic choke, which is not working at the moment, so I just make sure the choke flap is closed when I start the engine, and then gradually open it by hand as the engine is warming up.
Erm, by a heat riser do you mean the flap that closes off the exhaust and sends the gasses back over the inlet manifold? There was one of those on the passenger side, but I removed it, as it was getting stuck closed and causing overheating. Don't think there's anything on the drivers side.
Since you bought the car with the rebuilt engine and were not there when it was assembled there is the possibility that you may have a valve that is not closing completely. I would do a compression check on all cylinders. That will at least give you a base line for the engines actual condition. Also GET RID OF THOSE GLASS PETROL FILTERS! I had a friend lose his car do to an engine compartment fire when one of those broke. KK
My family have owned the car since 1993, was my mum's daily driver, then in 2003 the engine seized while the car was being stored, so I finally got around to pulling the engine in 2012 and had it rebuilt by a local engineer with a good rep for building V8's. The white smoke that's sometimes comes from passenger side I have worked out is just some water vapour, i Started it this evening and both sides now had a little, it clears up after the engine has been warmed up. What I do have though is when the engine has warmed up, when i switch it off, it tries to carry on running a couple seconds. Is this too much fuel still trying to ignite in the hot engine? Or bad timing? It runs ok when warm, a little pop now and then depending where the choke is positioned. The funny thing is, when my mum drove it every day for 10 years, it had an old Holley 2 barrel very poorly fitted ( practically balanced on the top of the inlet, you coulda knocked it off) and it ran fine. How do I tell if a valve is sticking?
Sounds like dieseling or run-on. Research it. Lots of info out there. Basicaly your idle setup is out of whack.. You need to check your throttle stop screw and timing curve/vacuum advance. As for valve action... Leak down test And compression test, static and running compression test.
I've started using a fuel additive to the unleaded petrol that i have to run it on, and it seems much better, seems to have stopped the run-on. I also took the carb apart again, re set the float. Gave it a good blowing out, and together with the additive, seems to be running smoother from both exhausts. No popping or lumpyness. Also, the engine seems to run smoother if I set the idle tickover fairly fast, ( don't know if this is because it's getting an excesive amount of fuel in it ) if I slow this down then it tends to run a bit lumpy. i tried setting it to 485rpm as noted in workshop manual, and it sounds like it's screaming at this speed. In order to set the timing mark using a light, it needs to be running at 400rpm, to do this i have to turn the idle throttle screw in to speed the engine up, but like i say sounds like it's running way too fast.
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