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setting valves on a 353

Started by drbrommerich, March 15, 2017, 04:24:19 PM

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drbrommerich

On readjusting the lifters on a 1930 Cadillac 353, can I just take the carburetor off and take the cover plate off to adjust or would it be easier to take off the whole intake manifold? Thank you for your information. Is there anything that I should be aware of? Dave
David Brommerich,CLC#23661
1930 Cadillac 4-dr Sedan
1930 Cadillac 4-dr Sport Phaeton

31caddy

What I do is remove the four bolts ( two on each side of the carburetor) that hold the aluminum portion of the intake manifold to the cast iron portion of the intake manifold. Then the carburetor and aluminum section of the intake are lifted out as an assembly, and reinstalled as an assembly. If your exhaust cross overs have not been blocked off, remove the two bolts on each side that attach them to the exhaust manifolds, and the cross over tubes then come off as part of the assembly. Soak those bolts good with kroil oil if they have not been off in a long time. You don't want one breaking off in the manifold. If that does happen, its not a disaster though. Those bolt holes go clear through the exhaust manifold, so it is not too difficult to drill clear through the broken bolt and re tap the hole while stuffing a grease coated rag or similar inside the crossover hole to catch the chips.
R. Rowland CLC #28971

1931 Model 355A Sedan (Recently sold)
1931 Model 355A Fleetwood 4535 Convertible Coupe
2005 Cadillac XLR

drbrommerich

I took a better look at it and if I just take the bolts out of where the aluminum meets the cast iron, It looks like I could leave the carburetor on, is that right?  Dave
David Brommerich,CLC#23661
1930 Cadillac 4-dr Sedan
1930 Cadillac 4-dr Sport Phaeton

31caddy

Yes Dave, that's what I was trying to describe. You never have to separate the carburetor from the aluminum intake during disassembly or reassembly. This is much easier and quicker. Also, you need to get the intake out of your way anyhow, as you will have much difficulty doing a precise job of adjusting the tappets with it installed. Two new gaskets will be required for the intake, and two for the exhaust crossovers.
R. Rowland CLC #28971

1931 Model 355A Sedan (Recently sold)
1931 Model 355A Fleetwood 4535 Convertible Coupe
2005 Cadillac XLR

drbrommerich

Thank you so much for the information. I ordered the new gaskets and they came in two days. When the mechanic came over and heard it run, we are going to do a couple of other things first.  We first changed the spark plugs and it runs very well. We then took it for a drive and noticed at about 35 mph it was lacking power so he is going to bring over his timing light. It runs perfect at lower speeds. Would you have any other suggestions?   Thanks,   Dave
David Brommerich,CLC#23661
1930 Cadillac 4-dr Sedan
1930 Cadillac 4-dr Sport Phaeton

31caddy

You might want to warm it up and do a compression check. Open the throttle wide open ( to draw in maximum air charge) with the steering wheel throttle control while cranking. A real good cylinder should show 80 psi on that engine. Stuck valves are common on these engines if they sit a long time.
Timing is set on these engines with them not running. You will notice that the distributor is fixed in position except for the few degrees that the spark control moves it. The distributor cam has a locking screw that allows you to unlock the cam and rotate it in relation to the points without turning the distributor shaft. The procedure is in the manual.
R. Rowland CLC #28971

1931 Model 355A Sedan (Recently sold)
1931 Model 355A Fleetwood 4535 Convertible Coupe
2005 Cadillac XLR

drbrommerich

The mechanic is coming back next Monday and I will have him bring his compression checker. When we turned the knob on the carburetor which gave it more gas, it runs great at faster speeds, but when we idle it, we smell a lot of gas fumes. Is there another adjustment on the carb like a fast or slow idle? Thanks, Dave
David Brommerich,CLC#23661
1930 Cadillac 4-dr Sedan
1930 Cadillac 4-dr Sport Phaeton

harry s

As R Rowland mentions timing is set with the engine not running.  Once it is set you can verify with a timing light. Getting the perfect setting on each bank can be a tedious process but worth the effort in performance. Good Luck,   Harry
Harry Scott 4195
1941 6733
1948 6267X
2011 DTS Platinum

31caddy

Quote from: drbrommerich on March 21, 2017, 10:51:19 AM
The mechanic is coming back next Monday and I will have him bring his compression checker. When we turned the knob on the carburetor which gave it more gas, it runs great at faster speeds, but when we idle it, we smell a lot of gas fumes. Is there another adjustment on the carb like a fast or slow idle? Thanks, Dave
I deliberately did not go way into the timing procedure because, although not really difficult, it would take two pages of typing for me to describe it. I usually align the proper timing mark on the flywheel and then remove the distributor and time and synchronize the points on the bench using the special tool, as it is much easier than trying to do a precise job of it while leaning over the fenders.
There are no other external carburetor adjustments other than the stop screw where the throttle rod connects to the carburetor. The book says to set this so that the engine idles warm at around 320 rpm. The large brass mixture screw on the top that you adjusted makes it richer when you turn it in clockwise and leaner when you turn it out counter clockwise.
It appears that the engine is going lean as rpm increases from what you described. Turning the mixture screw way in somewhat compensated for this, but left you way rich at idle. So, ask yourself why. The float level may be set too low, or perhaps you have a restricted fuel line or crud in the bottom of the vacuum tank. Check for a vacuum leak as well, especially in the windshield wiper system on the passenger side of the firewall. It's hard to troubleshoot and offer sound advice from a distance, but these are things to check.
R. Rowland CLC #28971

1931 Model 355A Sedan (Recently sold)
1931 Model 355A Fleetwood 4535 Convertible Coupe
2005 Cadillac XLR

drbrommerich

Thank you both for your information. The mechanic took the book home with him and is going to read up on it. He did show me the inspection plate he has to take off if he times the engine. I will show him this info that you sent me also. Again, thank you so much.   Dave
David Brommerich,CLC#23661
1930 Cadillac 4-dr Sedan
1930 Cadillac 4-dr Sport Phaeton

Carl Fielding

Do you guys set your static timing a few degrees advanced over spec for the too high octane gasoline these old cars have to suffer now ? Also , David , this is a very good time to block off the exhaust heat from the intake manifold. Use steel plates , not aluminum. See about putting an insulation block between the carb and intake manifold also. With these wise adaptations to run better on modern gasoline , your carb will still be plenty warm to avoid carb ice when warm. If you are driving before warmup in cold  high humidity conditions, it is conceivable that you MIGHT get some icing. Not likely if your apparatus is similar to what we have on the slightly earlier cars. Block it , break the thermal bridging , and your car will run much better in the cruising season. If you need further technical data/info to validate what the reason for this improvment is , Marks Mechanical Engineers Handbook 2nd Ed , 1924 ; 3rd Ed , 1930 ; and 6th Ed , 1958 under "Gasoline" will convince you. If you are a better computer jockey than I am (most people are) , you should research gasoline distillation curves in various periods , say early 'teens , mid 'teens , early - late '20s , and late '30s. Every curve tells a story. That story will reveal to you the necessity for the intake "ovens" back in "the day" , and the need to  block them off to the best of your abilities these days. I can further elaborate if you would like. Drop that intake temp ! Your ancient Cadillac will thank you !  - Cadl

DFarlow

Could you note who supplied your gaskets for the 1930 V-8?  Didn't know where to go for these.
David