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I’m stumped about several things with my ’67 327 Holley carb. I’ve been upside and down the threads here and elsewhere, videos and Holley website. I could use some advice. Carb is a Holley 3810 Non-Adjustable Float Carburetor (pic attached). No float adjustment screws. First questions. Looks to be a Nov. 1961 carb (1A3 stamp)? I guess it’s a replacement carb?
The problem. About a week ago I went for a drive. Everything’s fine. Next morning car won’t ideal, flooding, plugs soaked, … I poked around a bit (bit=+8hrs). I decided to call for help. Local Vette shop that seems to have a very good rep. They’ve had the car for a week now. Some ignition problems (new coil/capacitor, R43S plugs swapped for R45S). Sure. Whatever. They tried a “partial kit rebuild” of the carb. Went to pick up the car. Obviously not fixed. $1000 bill paid in full. They’re keeping the car for another week. Pulling the carb and sent to their "#1 carb guy" to be totally rebuilt and machined where necessary. Total cost for this phase about $700. Another week. I’m thinking if the car isn’t done by Friday next, put it on the flatbed and bring it home. Pick up the rebuilt carb when it’s ready. I install. You get the idea. 1) I don’t mind spending money since (as you guys would see it) I guess I'm not a "real Vette guy". 2) Maybe my patience isn't what it'll need to be for this project. I'd really appreciate any/all opinions about this and my "plan".
Apologies for staring a new thread. I'm still figuring out the protocol here. But I'm thinking an on-topic thread that's 5-10 years old isn't the best place for a post like this?
So tell me where you are with this tune up. How much $$ to date and is the car home with you finishing install or vette shop.
Sounds like the carburetor needed a overhaul kit plus the surfaces milled flat, plus, in the mean time you fouled the spark plugs with fuel so that made things worse.
Holley carburetors are modular in design meaning the metering blocks and float bowls attach to the main body and use gaskets to seal them. If the carburetor surfaces are not flat the gaskets will not allow a air and fuel seal between the two parts and result in internal leaks into the engine. When the engine is run, vacuum is created inside the engine and will suck air or fuel from these places that are not sealed together.
Your post states that you used the car and it ran fine and one week later you started experiencing problems, correct? That being the case the vette shop probably started with the right things like a tune up first but boy am I in the wrong business $$.
Your solution could be many little things from a tune up to carburetor maintenance to dirt in the fuel system etc. All a process of elimination but expensive if you are not familiar with old cars and have to seek out help.
Keep us posted on the progress and people will try to help because there are lots of very skilled people here on the forum, we just can't reach through the computer and fix it for you.. we can only make suggestions.
Not that it makes a lot of difference, but Chevrolet did not use Holley Carbs until '64. Ford started in the early 50s with the 4150; Chrysler in 1960 but with the 4160. If you get tired of working with a rebuilder, you might want to check this out.
So tell me where you are with this tune up. How much $$ to date and is the car home with you finishing install or vette shop.
Sounds like the carburetor needed a overhaul kit plus the surfaces milled flat, plus, in the mean time you fouled the spark plugs with fuel so that made things worse.
Holley carburetors are modular in design meaning the metering blocks and float bowls attach to the main body and use gaskets to seal them. If the carburetor surfaces are not flat the gaskets will not allow a air and fuel seal between the two parts and result in internal leaks into the engine. When the engine is run, vacuum is created inside the engine and will suck air or fuel from these places that are not sealed together.
Your post states that you used the car and it ran fine and one week later you started experiencing problems, correct? That being the case the vette shop probably started with the right things like a tune up first but boy am I in the wrong business $$.
Your solution could be many little things from a tune up to carburetor maintenance to dirt in the fuel system etc. All a process of elimination but expensive if you are not familiar with old cars and have to seek out help.
Keep us posted on the progress and people will try to help because there are lots of very skilled people here on the forum, we just can't reach through the computer and fix it for you.. we can only make suggestions.
$1000 to date and the shop still has the car. Another $700 when the carb is reinstalled... later this week (I hope). It's been 40+ years since I worked on cars myself. NOT to the level of rebuilding an engine... but I'm okay with basics. 100 years ago I was a "mechanical" chemical engineer... still another type of engineer today. e.g. I rebuilt my home audio, automation, security, network, vpn, ... from the ground up. Different kind of mechanical, I know. But I can figure my way though some problems. I've only own the Vette for 6 weeks now. I'll figure out what I need to know, can know, and can do with time. I hope.
Back to the $$$'s. The shop that has the car, $150 per hr? $1700 to really fix the carb (6 hrs to shop plus a rebuild)? I guess that's reasonable.
Not that it makes a lot of difference, but Chevrolet did not use Holley Carbs until '64. Ford started in the early 50s with the 4150; Chrysler in 1960 but with the 4160. If you get tired of working with a rebuilder, you might want to check this out.
.http://www.specialtypartsdirect.com/...New-_p_24.html
Great point. Started typing too early in the morning. I guess it is 197(1). That makes sense?
That makes more sense. 19th day (Jan 19) 1967 is the production date. Not sure about your parentheses around (1). If that is the case, the production date would be 197th day in 1971.
The parentheses is just me highlighting the 1. That said, the decoding for my 1A3 "Three Digit Date Codes" is;
that picture of your carb doesn't look correct to me as it should have a transfer tube for a 4160 carb. it seems your shop has really no clue what they are doing with a carbed car and just guessing at this point after a tune up didn't work. there a few people that are trust worthy with Holley carbs that I would send it to and have a basic rebuild and gone over.
I think you are just throwing money away at that shop. With your background you should not have any problem pulling a Holley carb apart, check the float and needle/seat assemblies, set float level and so forth. Get some re-usable blue gaskets, a rebuild kit, some spray carb cleaner and a Holley book from the nearby Barnes and Noble and dive in. Sending the carb off to a good-reputation carb restorer is not a bad idea if it's the original. It will come back looking brand new and should be 100% functional - but $700 sounds a bit steep.
Holley externally adjustable float bowls will usually swap onto a 4160 carb - not completely sure about the 3810 model - it would lose the front bowl vent and originality. But your stock 3810 should work fine if clean and adjusted properly.
Depending on how much flooding you had, you may want to consider an oil change.
The problem. About a week ago I went for a drive. Everything’s fine. Next morning car won’t ideal, flooding, plugs soaked, … Some ignition problems (new coil/capacitor, R43S plugs swapped for R45S).
If the car truly "ran fine" the night before and the next morning, it won't idle and the plugs are loaded up, I'd suggest you had a piece of dirt in the needle/seat letting the carb flood. That'd take about 30 minutes, tops to fix and no need for total carb rebuild and machined.
The plug change was okay. I think their labor charge is outrageous, especially for basic tune-up work. But hey, I live deep in the heart of fly over country and things are relatively cheap here. Including labor for things of this nature.
I'd suggest you stay way away from the $150/hour Corvette shops and find you an experienced back alley guy to work on the basic things. $20/hour.
I think you are just throwing money away at that shop. With your background you should not have any problem pulling a Holley carb apart, check the float and needle/seat assemblies, set float level and so forth.
Exactly what I was thinking. But I'm in new territory with the car. I wouldn't say the shop talks to me like I'm an idiot... but close. And for a $150 "expert" I expect a lot. In my old day job the numbers were a lot bigger and my 2-cents was... well... listened to differently.
Float bowls with externally adjustable needles were on the previous year's 1966 Corvette carb, the Holley 3367. Buy a pair of those, bolt them onto your 3810 and adjust away. No other changes needed. Guys have been doing this since the 3810 came out.
As you describe the issue, the engine's running way too rich.
I had a similar problem was tricky to find: It was the power valve. More precise: the gasket.
The power valve is mounted inside the bowl and activated by negative pressure from behind the flap.
It is sealed by a fiber ring. That ring was somehow by age a little bit less thick and was not pressured as hard as necessary.
After replacing that fiber ring everything was fine.
I see no need to replace the float bowls with the external adjustment kind. The floats are very easily adjustable internally in the bowl, once you remove the four screws. And you don't need to mess with them after you set them. Not something you have to constantly fiddle with even though many apparently do.
I would put a set of adjustable float bowls on. Can’t tell from the pic, but do you have the large area screws in the side of the bowl (sight window)? That can tell you quickly if it’s a needle and seat being held open. A torn power valve can hemorrhage fuel as well. I had a float leak and when it became fuel logged, it began to sink, holding the valve open.
My guess was the partial rebuild was no more then a an external hosing with carb cleaner.
I am with Mike once you set the floats your done for ever. no need to go back and fiddle with them so why go buy parts you don't need. fix whats broken and don't create other problems
I would put a set of adjustable float bowls on. Can’t tell from the pic, but do you have the large area screws in the side of the bowl (sight window)? That can tell you quickly if it’s a needle and seat being held open. A torn power valve can hemorrhage fuel as well. I had a float leak and when it became fuel logged, it began to sink, holding the valve open.
My guess was the partial rebuild was no more then a an external hosing with carb cleaner.
No screws in the side of the bowl. I think you mean this side?
that picture of your carb doesn't look correct to me as it should have a transfer tube for a 4160 carb. it seems your shop has really no clue what they are doing with a carbed car and just guessing at this point after a tune up didn't work. there a few people that are trust worthy with Holley carbs that I would send it to and have a basic rebuild and gone over.
The transfer tube is visible, though it's partially obscured by the angle from which the picture was taken.
09-23-2018, 08:20 AM
Holley 3810 Non-Adjustable Float Carburetor questions
I hope.
