Hi Folks. I have series 5 water jacketed weber intake with small tipped vacuum at bottom which does draw vacuum. Shouldn't it be closed off. It has the dreaded hesitation and I've read the water actually helps with fuel atomization in delivery. Thanks for any opinion
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Series 5 intake vacuum relief
- Thread starter glassman
- Start date
husky drvr
Diamond Level Sponsor
Opinions, everybody has one, not all are the same. What are your goals?
The small, open tip drain is the later style which started sometime in the year of s3 production. It works fine as is, at least it did with the Solex carb on the 1725 in the Husky. Obviously, the factory considered it to be a needed item or the money for the machining, parts, and installation labor involved would NOT have been spent.
Things change over the course of time. Your Weber is not the same as the OE Solex. Today's fuel mixtures are not the same as was available when these engines were designed and specced in the 60's. Even if you are using non-ethanol fuel, today's fuel generally has a more volitale compound combination to aid vaporization as an emissions improvement aid. If you are using a fuel with ethanol, then due to the difference of BTU's contained in gasoline and ethanol at a 90/10 ratio, you are only delivering about 95% of the fuel BTU's the engine thinks it should have at a given load and throttle position. In other words, you are 5% lean at all times if your intake system is delivering the fuel volume of your engine's OE design parameters.
Thoughts and opinions on improving your hesitation situation:
Your drain - for now - leave it in place. For tuning purposes, you could hook a vacuum gauge there.
I used to wrap the lower part against the exhaust down-pipe - open tip away from down-pipe. When the engine is running, the overall amount of air delivered to the manifold is a small percentage of requirements. With vacuum in the manifold, it's not possible for fuel to run out. By heating the drain pipe, the air traveling through the pipe is heated which also lowers the volume of air ingested through the drain. When the engine is shutdown relieving manifold vacuum, IF there is fuel puddled on the manifold floor, that fuel if it runs down the drain will boil and rise as vapors back into the manifold until some cooling has occurred.
The point is the drain is not a significant part of your hesitation issue. Use it or not as suits your opinion.
Now for actual suggestions of possible benefit. The generic Weber 32/36 DVG used on the OE manifolds is a "best guess" for Weber's engineers as far as jetting in an installation. It's a compromise to be a "close" a fit for as many applications as possible. It's not fond of the log style manifold. It was found long ago that some Alpines had a hesitation on initial throttle input. Sometimes that can be helped to some degree by enriching the idle jet, possibly the primary main jet, and maybe the pump shot timing. Sometimes that isn't very effective.
Before playing with the carb jetting, checking the ignition system would be a higher priority. Pully timing mark lines up with TDC, no major wear in distributor shaft, vacuum advance canister hooked up properly and working ( if you've not tried running an engine with a disconnected or defective vacuum advance, it causes a bad off idle response and destroys fuel economy ). In short, verify everything in the ignition system is optimized, adjusted properly, and correctly functioning. You'd be surprised how many carbs are blamed for a challenged ignition system.
Finally, if you have a PCV valve connected, try blocking it off and see if re-tuning the engine shows any improvement. If you have the OE PCV then it may be worn out, missing parts, or dirty. If your OE PCV has been replaced with some similar valve that fits, it might be one that is designed to have the vacuum source applied in the other direction. The amount of flow is governed with manifold vacuum pulling the spring loaded spindle against its seat to restrict flow at high vacuum. If the valve is flowing in the wrong direction, there is a chance the spindle's retainer can be broken or defeated allowing the engine to ingest the spindle and destroying the engine - it has happened.
Sorry for the dissertation but maybe it can help,
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Thank you so much Husky drvr I have had the distributor rebuilt seams to operate correctly. I've moved the timing around 11' even tried vacuum adj which I didn't like, so I settled about 12/13'. I went and connected the log intake anyway to the cooling system to see if the fuel suspension helped, but it didn't. I had fuel literally drip out of the vacuum tip during different efforts to check things, so I plugged it thinking it would be drawn back in. But I agree the small vacuum it pulls can't make it much leaner . I've changed the idle jet #60/65 didn't do much for it left, at 55. I like the pcv idea , will check out. I believe the real issue is the downward draw next to the two ctre chambers then making 90' just too lean at first gulp. I plan on playing a little more and maybe go back fix my storms and make it right. Thanks again Husky drvr
Shannon Boal
Platinum Level Sponsor
Hesitation....off idle, three things work together for a responsive throttle. One, is ported vacuum advance. The advance is controlled by vacuum signal peaking at slight opening of the throttle. Evaluating that involves measuring the vacuum supplied off idle from the carb (5-7 inches IIR) and timing advance observed when applying vacuum to the distributor. (Mechanical advance is not a big factor off-idle.) Two is the acceleration pump. Make sure that sprays visible fuel looking down the carburetor throat while actuating the throttle. Three is the idle circuit progression ports. The amount of fuel available there is limited by the idle jet. My way of evaluating it's size, ( too small/ too large), is this.....how many turns out is best idle obtained on the idle mixture needle? If it is 1/2 turn, that jet is probably too large, 3-1/2 turns, too small. I have Jerome's (Alpine Innovations Weber 32/36) system on my series V. The carb as received stumbled a bit, (worse with ethanol fuel, better with ethanol free), best idle 2-1/2 turns out. I went from a #55 idle jet to a #60 idle jet, no more stumble, best idle at 1-1/4 turns out.
husky drvr
Diamond Level Sponsor
Glassman,
Just out of curiosity, what is the serial number on the cylinder block in your Alpine?
It might also help, if you know what the distributor number is, to post it as well. Who rebuilt it for you?
Does the vacuum canister on your distributor have more than one vacuum connection port? Wild thought, and hopefully irrelevant.
Just contemplating different possibilities,
Thanks guys for the input. I understand what you're saying so I'm going back to at it. I've been busy working on 2 old triumph Bonnievilles, I had to walk away. A guy on this forum years ago fixed the distributor ( very knowledgeable) I don't remember his name. I will d/b check vacuum #s and distributor #. Engine # B39900071117 gtLrx.
Well I started to check the issues on the plate and now the new Chinese electric pump decided only to work for a few seconds if I smack it. It's 2 to 3 1/2 pounds I believe.Next, any suggestions on a decent price one, I looked at Carter and they seemed too much pressure output? I've been at this car for 47 years now, it will see it my way or I'll burn it to the ground. Thanks again
Shannon Boal
Platinum Level Sponsor
One thing after another!
husky drvr
Diamond Level Sponsor
Wonder if it was Jan?
Your serial seems to be for a 1969 Alpine GT - but digit count is off. Probably the table I copied from.
Does your engine have an aluminum sump? The '69 engine was built to "meet" the days emission standards, but may not have a PCV valve. Would depend on how much and many parts were changed to achieve fitment in an series Alpine. The series Alpine intake your using should have one.
| Alpine G.T. (North America only) | B399000001 | 1969 |
Tim R
Silver Level Sponsor
Glassman,
The Facet low pressure pump is what we use on two of our Alpines but we run it through a regulator to ensure that pressure stays low. You want about 2.5PSI, a mechanical pump will happily deliver that if that is an option for you.
As far as the drain on the manifold is concerned there is a detailed explanation of it on the Sunbeam Alpine Channel in 'The History of the Club Weber Carb' video. Basically the 'Log' manifold was a nightmare and as liquid fuel built up in the inlet manifold the pipe let it drain way. The Curved inlet manifold sold by Alpine Innovations is a remarkable upgrade for an Alpine. When matched with a Weber 36/32 the car will fly. Our car was totally transformed by it and the miles per gallon went up so much that it paid for itself remarkably quickly. We don't run a PCV on our car but have a pipe from the rocker cover to the air intake pipe. This reduces crankcase pressure and leaks.
The picture is of my son's Series IV automatic. The Facet is mounted under the car near the battery box, the pressure regulator is visible as is the pipe to the air intake from the rocker cover.
Tim R
The Facet low pressure pump is what we use on two of our Alpines but we run it through a regulator to ensure that pressure stays low. You want about 2.5PSI, a mechanical pump will happily deliver that if that is an option for you.
As far as the drain on the manifold is concerned there is a detailed explanation of it on the Sunbeam Alpine Channel in 'The History of the Club Weber Carb' video. Basically the 'Log' manifold was a nightmare and as liquid fuel built up in the inlet manifold the pipe let it drain way. The Curved inlet manifold sold by Alpine Innovations is a remarkable upgrade for an Alpine. When matched with a Weber 36/32 the car will fly. Our car was totally transformed by it and the miles per gallon went up so much that it paid for itself remarkably quickly. We don't run a PCV on our car but have a pipe from the rocker cover to the air intake pipe. This reduces crankcase pressure and leaks.
The picture is of my son's Series IV automatic. The Facet is mounted under the car near the battery box, the pressure regulator is visible as is the pipe to the air intake from the rocker cover.
Tim R
thanks. I believe the log needs to go down the river. I'm still waiting for the new pump though. I'm going to contact alpine innovation and do it. I like the valve cover relief going to the air filter instead of PVC valve. I changed the pushrod cover to one with a vent too, I believe it helped. How many degrees approx does the distributor change on acceleration with a light, vacuum line disconnected? I'm having doubts whether it's working properly. I had it rebuilt years ago. Well I can't check anything till my pump comes. I'll respond ASAP. Thanks again
husky drvr
Diamond Level Sponsor
As long as the installed distributor is for a sV.
I'm wondering if he might have the distributor for the engine installed (probably a '69 Alpine GT coupe) instead of a "correct" sV distributor.
Just a thought,
Thanks for the numbers and I'm going to check the distributor for a year. Is there a graft of distributor #s for different years on the web ? I'm supposed to get the fuel pump Monday. I texted Jerome and he doesn't want to sell only the Weber intake manifold I've never spent that much money on the car so I don't know what I'll do. I still have the strombergs and may just repair them. After 47 years ownership we may just go back and punt
husky drvr
Diamond Level Sponsor
At the top of the chart Mr. Hartman posted from WSM 145 is the Despatch # 41077.
That is the number for a series V distributor and is stamped on the side of the distributor body.
Each unique distributor application has its own despatch number with the timing specs found in its WSM.
If your distributor body is stamped differently, then it's not a sV distributor.
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Thanks so much. I am looking forward to getting it out. Put some miles on last. Year and thought maybe I could upgrade the carburetor system but after all these years I don't want to spend that kind of money. Just holding my breath on social security. Thanks again everyone
Shannon Boal
Platinum Level Sponsor
Simple and cheap test....hook a vacuum line to the distributor with the engine running and suck on it. You should hear the engine perk up from the advance. (About ten degrees). Don't worry too much about the mechanical advance, it lags behind the vacuum advance, not reaching ten degrees until the engine has already accelerated to 1500 RPM or so.