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Just got the Rocket 350 back from the Shop. Totally rebuilt. Car is not firing right and stalling out, What would cause this? I am using race fuel given the cam but its still acting funny. thoughts?
Last edited by sjay1989; August 14th, 2019 at 08:49 AM.
Reason: spelling
Your'e looking at a two prong approach. Do you have any helpful mechancally inclined friends or relatives?
One-You want to verify the condition of your ignition parts like plugs, wires and distributor cap and rotor...points too. This includes ignition timing.
Two- You want to verify proper operation of the accelerator pump with squirts of gas when you operate the throttle. You'll need to look down the carb to confirm this. Next is the choke settings. Make sure its closes on a cold engine and when warm, its mostly open.
Among the usual hand tools, you really need a dwell meter to measure point dwell and a timing light. A vacum gauge would be helpful too. Can you confirm you have points ignition or has somebody converted to electronic ignition?
Just wondering where I should begin as Im not mechanically inclined.
I'm assuming you don't own a timing light, tach and dwell meter, or a vacuum gauge? Do you own a basic set of hand tools. If this is something you don't want to learn and you have a decent wallet depth then take it to a mechanic that knows how to tuneup an old car. If its something you wan to learn then buy the above items and dig in, there are people here that can walk you through a basic tuneup. We all were not very mechanically inclined in the beginning either.
The tool purchase is where to start with the addition of a chassis service manual for your year car. Pull up some youtube videos on how to tune an older car to get an idea of what your getting in to.
You can still find some really good Old school speed shops in Toronto.
I've drained my wallet several times over the years prior to becoming a member here on Classic Olds .
However, If your ready to learn as I was, Oldcutlass nailed it down for you as to how to begin.
In the meantime, once you have it running feathering the gas pedal until its warmed up. Pull the air cleaner off and take a pic of the carb and post it here. We can see if your choke is opening the butterfly up enough to keep it from stalling all the time.
You may need a new choke pull-off, vacuum line, or choke stat depending on what carb is on the car currently.
In the mean time, you can try running/driving it without the gas cap on to see if its venting properly. On my Cutlass I was having issues and noticed the vent hoses on top of the gas tank have been kinked and smashed up behind the bumper. Gas cap was not a vented type. Fuel pump sucking+no air getting into tank= random stalls
Maybe the random stall is related to float level? When I had an ebrock, my car would stall 1 out of five times turning in my driveway, I found the float a little high. I had a sled that displayed similar random stalling 1 carb had a badly misadjusted float.
if you don't have the manual for the carb you can find them online.
If the pic you posted was after the engine was at or close to operating temperature then the choke appears to be working. The carb does have the sooty look which indicates a rich condition. A possible dieseling condition due to timing as well. The plugs will also show what you see inside the carb.
Next, Before start-up cold.
What type of inline fuel filter are you using? If clear view, how does it look? Before start up... any fuel in the filter? After start up, full of fuel or do you see a small air pocket ? Check all the fuel lines.
I would begin by pulling the plugs, cleaning/replace and re-gap them. Purchase a vacuum gauge and timing light. Check the vacuum once you re-install the plugs then check timing.
If the vacuum gauge is bouncing around a little, check all vacuum lines, base gasket on carb etc.
Then check timing, adjust if necessary then set the idle mixture screws to get an even idle if possible.
Try to report back if you can purchase the tools to perform the above, at that point members can assist in tweaking and checking for heat soak at the carb, float level, timing chain stretch, etc.
Others here will also advise to what I have mentioned on expand on it to assist further.
I would also look closely at your battery cables and connections. Your engine ground strap looks original and may need replacement along with the regulator. 50 years is a lot to ask from any electronic component. I hope you find the problem.
Marvel Mystery Oil takes the win over any adjustments. I should have tried that before spending a few hundred bucks on wrenches, sockets and diagnostic on tools.
Good to hear its running better again.
I am ordering a vacuum gauge and timing light. Any tips/ideas appreciated.
You're half-way there regarding the tools required to complete a tune-up. Assuming you aren't looking to purchase top-of-the-line high quality automotive tools to be used on a daily basis to provide income, you can stick to the low-end price range tools. You will need a dwell meter & a tachometer. This item (below) from Harbor Freight measures, dwell, engine RPM (tachometer) & operates as a multi-meter. The other item I'd suggest you pick up is a simple feeler gauge ($2.00) to set the gap on your spark plugs and the points gap in your distributor.
TIPS: There is only one sequence to tune-up an automotive engine:
(1) Set/Adjust dwell angle (dwell meter)
(2) Set/Adjust timing (timing light)
(3) Set/Adjust carburetor (vacuum gauge)
As evidenced from your photo, you have the standard OEM points system and you do not have an HEI system. You also have an electric choke as evidenced by your photo.
Look on your radiator fan shroud. See if there is a tune-up specification label. This label will list/identify the specifications for the engine tune-up.
Page 6C-11 of the 1971 CSM (which should be the same specifications on the shroud label) - although the shroud label won't list the vacuum.
If you intend to own your car for any length of time, and you want to learn and work on your own car (saves lots of $$$), invest in a CSM (it's the bible for your car).
IDEAS: Examine your ground wires on the car. Remove them and clean each of the ends which attach to the engine block. Don't be afraid to remove any of the grounds - battery cable terminals, ground straps, ground wires. Clean them w/ a wire brush, apply some dielectric grease and hook them back up. I noticed one ground strap your firewall leading to a bolt on the top of your engine. That bolt looks very rusted. Remove and clean that bolt and the ground strap. I don't believe I have the same ground strap on my 1971 CS in that location, but that's not a big deal someone may have added that ground strap which is fine. But, the grounds must be clean. Bad grounds increase the resistance of the entire electrical circuitry and can cause serious issues with maintaining good performance.
I would look up the purpose of the high voltage ignition coil and how it operates so you can gleem an idea of the importance of the high voltage ignition coil & how it operates with regard to your points gap, spark plug gap, dwell, and timing.
Tough for me to tell in the photo, but if the braided ground strap from the firewall is tied to this bolt (red), the ground strap end on the bolt needs to be cleaned, and the bolt itself completely cleaned or replaced with a clean bolt. Clean all your ground wires while you're waiting on your tools to arrive or get purchased.
I will work on the ground wires tonight. Pulled the plugs and noted they are Champion RY18YC which ought to be 0.035" gap. Assuming my motor is actually a 1971 the plug recommended is RY14YC which has a gap of 0.40". Might get new plugs. Any issues with ordering the RY18YC again?
The Champion RY18YC is a slightly hotter plug than the AC R46S, but the RY18YC will work fine. The Champion recommended spark plug is RJ14YC.
The AC R45S or equivalent would be a better cooler running plug. Any of these plugs are suitable >>> https://www.rockauto.com/en/catalog/...park+plug,7212
You should be able to obtain any of these at your local auto parts store.
While you're getting things ready, as has been mentioned several times, the Chassis Service Manual (CSM) is the absolute best service manual to assist you for years to come. It contains the information you need to perform the basics & advanced maintenance on your vehicle. Do not purchase the software, digital editions - purchase a paper copy. I've provided you a link for several - you get what you pay for. I'd get the Used - Very Good condition if it were me. I own an original in excellent condition. You will not regret having the correct documentation for your vehicle. Check elsewhere you might find a better price, but this listing demonstrates about the correct price you'll pay anywhere.
Taking the day off to go tool shopping. In regards to Timing lights, will a simple one suffice or do I need the one with the Electronic timing advance ****? Not alot of information online regarding the difference between $50 gun vs. $150.
Cleaned up the ground wires. Wires were good no issues just surface rust on the outside of the bolt not anywhere important. Hooked up vacuum gauge to the carb the vacuum port for the drivers side which was capped off. Engine warmed up and at 900 RPM, I am getting 14-15" of vacuum. Relatively consistent. Before adjusting the screws it was dancing erratically between 12-15".
I have not checked timing yet.
Last edited by sjay1989; August 15th, 2019 at 08:59 AM.
You're trending in the correct direction. A proper tune-up is always performed in the following sequence as noted above. Dwell will effect timing, timing does not effect dwell. Therefore, establishing the dwell first is critical. Then, set your timing. Finally, you then adjust your carburetor. After having adjusted dwell and timing (NOTE: you must disconnect and plug the distributor vacuum advance hose when setting the ignition timing) you then adjust the A/F mixture carburetor screws to the highest vacuum you can achieve. Don't think because you have established a vacuum now it will suffice. You will need to adjust your A/F mixture again after you've established dwell then timing. It's always performed in the following sequential order:
TIPS: There is only one sequence to tune-up an automotive engine:
(1) Set/Adjust dwell angle (dwell meter)
(2) Set/Adjust timing (timing light)
(3) Set/Adjust carburetor (vacuum gauge)
Also, although I have not reread the thread, You need to check and/or replace any worn parts, all of your plugs, wires, cap, rotor, and the points prior to setting your tune. A new fuel filter if its been a while is recommended also.
Do you have the tune-up specification label on your fan shroud? It should identify the items I discussed above in Post #21
You'd prefer to be @ 30* dwell angle - it takes a couple minutes to adjust to 30* dwell angle. IMO, I'd prefer the dwell to error towards 31* - 32* as opposed to 29*. Small increments in dwell do have an impact on your next step which is the timing. To keep this short and sweet. You're at the base position of establishing when your distributor contact points open and close. You want the proper closed position (referred to as a collapsed field) when establishing your dwell. This electrical pulse is sent to your high ignition coil primary winding which establishes the ability to appropriately and effectively send the correct electrical current to your spark plugs to achieve the proper ignition during combustion phase. It only takes a couple minutes to adjust the dwell and your best time is now.
If by chance you're not comfortable w/ adjusting the dwell, 29* would suffice, but it would not be optimal. Ensure you get a good reading at various RPMs while establishing dwell - from the base idle RPM of ~1100RPM through ~2500RPM. Don't forget to unhook & plug the vacuum advance hose when setting your timing.
On the off-chance you may be wondering what the dwell angle is all about - it isn't that difficult. The engine camshaft is situated at a 90* orientation from the alignment of the distributor. The camshaft is pointing front-to-rear of the engine (horizontal), the distributor is pointing top-to-bottom and the bottom gear of the distributor meshes into the camshaft - therefore the distributor rotates 90* to the camshaft (at ~1/2 engine speed). When arriving at the dwell angle, it's simple. There are 360* to a full circle of rotation. The distributor and the engine both rotate 360* (90* from each other). You have 8 cylinders. Therefore, each cylinder comprises 45* dwell angle (360/8 = 45). There are 8 lobes on the distributor shaft - one for each cylinder. Each lobe rotates to open and close the points. Therefore, the lobes spend 1/2 time open and 1/2 time closed. So, they spend 22.5* of time open & 22.5* of time closed. Distributors are not built equally, the lobes on distributors are not all of the same size and the 'ramp' of each lobe (the point where each lobe moves the points open and closed) is not the same on all distributors. Manufacturing engineers determine the optimum opening and closing of the points based upon the lobe parameters (primarily). Based upon your engine (350 cid), the OEM specifications call for a dwell angle of 30*.
30.0* minus 22.5* = 7.5*
The 'ramp' of the lobes on the distributor in the 350 cid sbo call for a 30* dwell because each side of each lobe is offset by ~ 3.75* (7.5/2) - the time it takes to ramp 'up' and the time it takes to ramp 'down' for each opening and closing of the points. One degree of dwell angle can make a difference - your call.
Much more than you might care to know, but it often helps to understand why you're doing what you're doing.
Distributor-to-camshaft rotation
Last edited by Vintage Chief; July 21st, 2019 at 08:06 PM.
Reason: sp
Leave all vacuum hoses hooked up while establishing the dwell. You only need to unhook and plug the vacuum advance hose when establishing your ignition timing.
When viewing your distributor cap, you'll notice a (generally) metal window on one side (generally the driver's side) of the distributor cap. That metal windows moves up & down - it generally has a lip on the top. Pull that lip upwards - the metal window will open. That metal window provides you access to the contact points of your distributor - it would be the same place where you would have initially established the base point gap for the points if you had installed new contact points. What you're achieving now is to optimally set the time the points open & close by adjusting the dwell angle (really nothing more than the best point gap possible - referred to as the dwell angle). Honestly, I can't recall what the size of the tool is I use to set my dwell - someone may have to chime in or I'll try to look it up. You can probably look for yourself and in some cases I think different contact point manufacturers over the years (by make and model) used various type screws - most were Allen Head screws, although I've seen some normal flat-head screws and some cross-tipped screws. I think my points use a #10 Allen wrench? I'll try to find it for you.
Anyways, w/ the dwell angle meter hooked up, the engine at 1000 RPM, the engine running at idle, the metal window open, the Allen Head wrench inserted into the Allen Head screw, you'll turn the Allen Head wrench to achieve a dwell angle of 30*. Done.
EDIT: If you had an old set of points laying about, you could look at the screw to adjust the points - if you have a set laying about. I may have a set laying about and I'll check.
Last edited by Vintage Chief; July 21st, 2019 at 07:58 PM.
No extra points in my parts bin. If I burn through a set of points, they generally are tossed out as is the case here. Anyways, to the point. I opened my distributor window and my points are adjusted with either a flat-head screwdriver or an Allen Head screwdriver/wrench. My points are AC Delco. Your points may be different. At any rate, you won't have any issue with seeing/visualizing the tip & size of the tool needed to adjust the dwell I can assure you. Open the window, use a flashlight and you'll readily identify the tool required.
With the window open, you can see my adjustment screw located on the right-hand side. It's actually both flat-head blade and/or Allen Wrench. Bad picture, lighting not optimal and angle difficult. You'll get it.
April 13th, 2019, 06:35 AM
