Poorly running Olds 350
June 24th, 2015, 09:16 AM
#1
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Poorly running Olds 350
I recently picked up a 66 Cutlass Holiday Coupe with a 350 in it. Based off the casting marks on the block and heads I'm guessing its a low compression engine from the mid 70's although I have not found the vin markings on the block yet to try and decode that. It has an Edelbrock Performer series intake & Carb (600 CFM I think). I don't know if anything else on it has been changed. When I picked up the car the carb was set so rich it would flood itself out at stoplights and the timing was set so far BTDC the timing mark on the balancer could not be seen at all. I have checked for vacuum leaks and was unable to find any, but that doesn't mean I there isn't one. Last night I tried adjusting the timing to 12 - 14deg BTDC but every time I got it close the engine would bog down real bad and die. When I advanced the timing well beyond 20deg BTDC it ran better but definatly not like it should. I got the engine idling around 750rpm and tried to balance the carb as best I could but it just does not seem right at all and my timing is still way to far advanced from what I have read on here. RPMs are around 500 when in gear and it does not die or stall. I do not have a compression or vacuum gauge so I do not know if I have any bad cylinders or if I have good vacuum.
I am thinking I should set the timing to 12deg BTDC and reset the carb completely and see if that helps any. Does that sound like a good starting point? At this point I am a bit lost because it just is not reacting like it should to tuning changes. Any and all advise is greatly appreciated, thanks in advance.
Kurt
I am thinking I should set the timing to 12deg BTDC and reset the carb completely and see if that helps any. Does that sound like a good starting point? At this point I am a bit lost because it just is not reacting like it should to tuning changes. Any and all advise is greatly appreciated, thanks in advance.
Kurt
June 24th, 2015, 10:36 AM
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It has a HEI unit, not sure year of the motor so I'm not sure if it is OE for that motor.
Update: On my lunch I was able to get the timing set to 14deg BTDC and leaned out the carb quite a bit. It is defiantly running better but still sounds a bit rough. That may be the hack job a previous owner did on the exhaust, they used the stock manifolds to make true duels and welded shut the passenger side crossover port. Oh fun times...
June 24th, 2015, 10:53 AM
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Since its an HEI it has about 18deg of mechanical advance and most likely the engine will like 18BTDC initial timing with vacuum advance disconnected @ 650 rpm. Make sure you have full battery voltage to it and not running off the old resistance wire. Also make sure your plug gap is .040-.045.
The best way to set your timing is 34-36 all in around 2800 rpm, then rev the engine to around 4500 while watching your timing and make sure it does not advance higher. Then note what your initial is for future reference. Doing it with the above settings requires limiting your vacuum advance if necessary so that it does not exceed 50 degrees of total timing with the vacuum advance connected.
The best way to set your timing is 34-36 all in around 2800 rpm, then rev the engine to around 4500 while watching your timing and make sure it does not advance higher. Then note what your initial is for future reference. Doing it with the above settings requires limiting your vacuum advance if necessary so that it does not exceed 50 degrees of total timing with the vacuum advance connected.
June 24th, 2015, 11:03 AM
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[Kurt] I'm sure that you probably already know this, but the vacuum advance must be disconnected and plugged before setting initial timing. It sounds like it's still connected, that's why I'm mentioning it.
Last edited by pmathews; June 24th, 2015 at 11:07 AM. Reason: for clarity
June 24th, 2015, 11:12 AM
#6
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Vacuum
The vacuum was disconnected and plugged when I was setting the timing. Although I am not sure I'm using the proper vacuum port on the carb. It is connected to the port on the passenger side, at idle it doesn't even feel like there is vacuum to that port and the engine does not respond at all to it being disconnected.
June 24th, 2015, 01:41 PM
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Leave it there or just disconnect and plug it for now. It's not needed for the car to run, its for fuel economy. By the way that's ported vacuum if hooked up there. Get your distributor timing setup first then we can go into setting up your vacuum advance. Do you have a dial on the back of your timing light where its adjustable?
June 24th, 2015, 03:10 PM
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Since its an HEI it has about 18deg of mechanical advance and most likely the engine will like 18BTDC initial timing with vacuum advance disconnected @ 650 rpm. Make sure you have full battery voltage to it and not running off the old resistance wire. Also make sure your plug gap is .040-.045.
The best way to set your timing is 34-36 all in around 2800 rpm, then rev the engine to around 4500 while watching your timing and make sure it does not advance higher. Then note what your initial is for future reference. Doing it with the above settings requires limiting your vacuum advance if necessary so that it does not exceed 50 degrees of total timing with the vacuum advance connected.
The best way to set your timing is 34-36 all in around 2800 rpm, then rev the engine to around 4500 while watching your timing and make sure it does not advance higher. Then note what your initial is for future reference. Doing it with the above settings requires limiting your vacuum advance if necessary so that it does not exceed 50 degrees of total timing with the vacuum advance connected.
"Make sure you have full battery voltage to it and not running off the old resistance wire".
Can you explain this a little further for me. I think I may have a similar issue.
thanks, Gary
June 25th, 2015, 12:46 AM
#11
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You might check the mechanical advance is working properly, if the springs are weak it will advance too quickly, if the advance weights are sticking it will not advance smoothly.
The timing should progress smoothly from no advance from its setting at idle to fully advanced around 3000 rpm.
Roger.
The timing should progress smoothly from no advance from its setting at idle to fully advanced around 3000 rpm.
Roger.
June 25th, 2015, 12:46 PM
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Eric - The timing light I have is not adjustable, however I'm looking into picking one up. I will check on the wiring for the distributor, I'm not sure if it is hooked to 12v from the battery or not but I know it is not connected to any cloth wiring. What gauge wire should I use if I rewire the distributor?
Roger - The advance is a but choppy, but then again I wasn't the smoothest on the throttle either. I will pull the cap and clean up the weights and springs. I'm guessing carb cleaner is sufficient for this?
Since I currently do not have an adjustable timing light what is my best bet for setting my advance beyond the limits of the stock timing indicator? Should I pick up a thing of timing tape, if so what diameter is the stock balancer?
Roger - The advance is a but choppy, but then again I wasn't the smoothest on the throttle either. I will pull the cap and clean up the weights and springs. I'm guessing carb cleaner is sufficient for this?
Since I currently do not have an adjustable timing light what is my best bet for setting my advance beyond the limits of the stock timing indicator? Should I pick up a thing of timing tape, if so what diameter is the stock balancer?
June 25th, 2015, 12:55 PM
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Also the stock throttle linkage has a bit of sideways slop in it and appears to touching the distributor. What is the best fix for this? I greatly appreciate everyone's assistance.
June 25th, 2015, 01:07 PM
#14
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Since its an HEI it has about 18deg of mechanical advance and most likely the engine will like 18BTDC initial timing with vacuum advance disconnected @ 650 rpm. Make sure you have full battery voltage to it and not running off the old resistance wire. Also make sure your plug gap is .040-.045.
The best way to set your timing is 34-36 all in around 2800 rpm, then rev the engine to around 4500 while watching your timing and make sure it does not advance higher. Then note what your initial is for future reference. Doing it with the above settings requires limiting your vacuum advance if necessary so that it does not exceed 50 degrees of total timing with the vacuum advance connected.
The best way to set your timing is 34-36 all in around 2800 rpm, then rev the engine to around 4500 while watching your timing and make sure it does not advance higher. Then note what your initial is for future reference. Doing it with the above settings requires limiting your vacuum advance if necessary so that it does not exceed 50 degrees of total timing with the vacuum advance connected.
I'm a slightly confused after reading above and other post about timing. I fully understand the timing concept but I see 18 deg@650 rpms base and 18 mech above but in other post I've seen 14-16 base and 12-14 base??
I have a 71 350 with ac and pwr brakes. The under the hood sticker has 12 deg @1100 rpms if I remember correctly. I have a new Taylor HEI dist that states it has adjustable vac advance (How does this adjustment work?). the carb is a Holley 650. it has new Taylor 8mm wires, new R46SZ plugs and the vac gauge is reading 22-24.
so what should my timing be set on?
what should the idle be set to?
it doesn't have an ac kickup solenoid on the carb I'm guessing idle should be higher than normal or get a solenoid?
what are your thoughts on this carb and/or a replacement.
would you set timing first they adjust carb?
http://www.summitracing.com/parts/ta...DtQaAgZB8P8HAQ
https://www.holley.com/products/fuel...parts/0-80555C
June 25th, 2015, 01:35 PM
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Eric - The timing light I have is not adjustable, however I'm looking into picking one up. I will check on the wiring for the distributor, I'm not sure if it is hooked to 12v from the battery or not but I know it is not connected to any cloth wiring. What gauge wire should I use if I rewire the distributor?
It should not be connected straight to the battery, usually its coming off the IGN terminal on the fuse box or they removed the old wire from the bulkhead connector under the master cylinder. Usually 12-14 gauge wire is used.
Roger - The advance is a but choppy, but then again I wasn't the smoothest on the throttle either. I will pull the cap and clean up the weights and springs. I'm guessing carb cleaner is sufficient for this?
I use electrical contact cleaner.
Since I currently do not have an adjustable timing light what is my best bet for setting my advance beyond the limits of the stock timing indicator? Should I pick up a thing of timing tape, if so what diameter is the stock balancer?
It should not be connected straight to the battery, usually its coming off the IGN terminal on the fuse box or they removed the old wire from the bulkhead connector under the master cylinder. Usually 12-14 gauge wire is used.
Roger - The advance is a but choppy, but then again I wasn't the smoothest on the throttle either. I will pull the cap and clean up the weights and springs. I'm guessing carb cleaner is sufficient for this?
I use electrical contact cleaner.
Since I currently do not have an adjustable timing light what is my best bet for setting my advance beyond the limits of the stock timing indicator? Should I pick up a thing of timing tape, if so what diameter is the stock balancer?
I'm having similar issues.
I'm a slightly confused after reading above and other post about timing. I fully understand the timing concept but I see 18 deg@650 rpms base and 18 mech above but in other post I've seen 14-16 base and 12-14 base??
I have a 71 350 with ac and pwr brakes. The under the hood sticker has 12 deg @1100 rpms if I remember correctly. I have a new Taylor HEI dist that states it has adjustable vac advance (How does this adjustment work?). the carb is a Holley 650. it has new Taylor 8mm wires, new R46SZ plugs and the vac gauge is reading 22-24.
The under the hood sticker does not apply as the original points distributor was replaced with your current one. They have a different timing curve. As far as how much initial it also depends on how much mechanical advance a distributor has, like I said most HEI's have 18-20 degrees.
The adjustment for the vacuum advance adjusts the amount of vacuum it takes to get the advance to start to move completely through its travel. You can vary the amount of vacuum it takes but not the total amount it will move. I like to limit it to 10 degrees and have it move completely at just under the max vacuum the engine produces.
All settings that I give are a starting point not etched in stone, some engines like more, some less, and some these are perfect.
so what should my timing be set on?
Start with the 18, the goal is to have a total around 36@2800-3000 rpm, again some like more or less.
what should the idle be set to?
You can run the stock idle settings or what ever the car is comfortable with. Again if you read the fine print in the manuals you'll see some where that they are not etched in stone.
it doesn't have an ac kickup solenoid on the carb I'm guessing idle should be higher than normal or get a solenoid?
Correct, what ever works best.
what are your thoughts on this carb and/or a replacement.
That spreadbore Holley carb has been used for years as a replacement, its a decent carb and if it works no reason to change it.
would you set timing first they adjust carb?
Timing first..
http://www.summitracing.com/parts/ta...DtQaAgZB8P8HAQ
https://www.holley.com/products/fuel...parts/0-80555C
I'm a slightly confused after reading above and other post about timing. I fully understand the timing concept but I see 18 deg@650 rpms base and 18 mech above but in other post I've seen 14-16 base and 12-14 base??
I have a 71 350 with ac and pwr brakes. The under the hood sticker has 12 deg @1100 rpms if I remember correctly. I have a new Taylor HEI dist that states it has adjustable vac advance (How does this adjustment work?). the carb is a Holley 650. it has new Taylor 8mm wires, new R46SZ plugs and the vac gauge is reading 22-24.
The under the hood sticker does not apply as the original points distributor was replaced with your current one. They have a different timing curve. As far as how much initial it also depends on how much mechanical advance a distributor has, like I said most HEI's have 18-20 degrees.
The adjustment for the vacuum advance adjusts the amount of vacuum it takes to get the advance to start to move completely through its travel. You can vary the amount of vacuum it takes but not the total amount it will move. I like to limit it to 10 degrees and have it move completely at just under the max vacuum the engine produces.
All settings that I give are a starting point not etched in stone, some engines like more, some less, and some these are perfect.
so what should my timing be set on?
Start with the 18, the goal is to have a total around 36@2800-3000 rpm, again some like more or less.
what should the idle be set to?
You can run the stock idle settings or what ever the car is comfortable with. Again if you read the fine print in the manuals you'll see some where that they are not etched in stone.
it doesn't have an ac kickup solenoid on the carb I'm guessing idle should be higher than normal or get a solenoid?
Correct, what ever works best.
what are your thoughts on this carb and/or a replacement.
That spreadbore Holley carb has been used for years as a replacement, its a decent carb and if it works no reason to change it.
would you set timing first they adjust carb?
Timing first..
http://www.summitracing.com/parts/ta...DtQaAgZB8P8HAQ
https://www.holley.com/products/fuel...parts/0-80555C
June 25th, 2015, 02:55 PM
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Eric - Thanks, I will try that and post back after. It probably wont be until next weekend as my schedule is fairly packed until then. Thanks for all the help, you have helped clear this timing issue for me.
June 25th, 2015, 06:54 PM
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Turn the engine until the balancer mark aligns with the O notch on the timing tab.
Draw a line on the balancer at the 10º notch using a white paint pen.
Turn the engine until your new 10º line is at the 0 notch on the balancer.
Draw another line on the balancer next to the 10º notch on the timing tab.
Repeat until you have 4-5 lines on the balancer.
Voila! Now you have a balancer with degree marks every 10º. I did this nearly 20 years ago and the marks are still there. In the early 80s I glued a timing tape on the balancer and it flew off during the first 5000 RPM pull.
Last edited by Fun71; June 25th, 2015 at 07:02 PM.
June 25th, 2015, 06:58 PM
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5 = 1968-69
6 = 1970
7 = 1971
7A = 1972
8 = 1973-76
June 25th, 2015, 09:04 PM
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Its even simpler to just get a good timing light, and will save all the cuts to your arms and spare the kids some interesting vocabulary lessons while trying get your hands down there to make the marks.
June 25th, 2015, 09:49 PM
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We all were and most of us didn't mess with HEI's back then either. We were still fiddling with dual points. I didn't know what new parts were until I was in my mid twenties. I owned stock in all the local wrecking yards.
June 28th, 2015, 06:55 PM
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Fun71 - The heads are #8 castings.
Since I no longer have the original Jetaway in it I know I don't need the bulky throttle linkage. Is there a factory set up from a later model that isn't as bulky or an aftermarket setup that will work well?
June 28th, 2015, 07:41 PM
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I don't have a Jetaway in mine either, I just removed the wiring harness and still use the stock linkage. However if your dead set on changing there are aftermarket setups that you can use. By the way, making duals the way your car is set up is the common practice. Headers for an SBO are very expensive for our body style not many available choices.
June 29th, 2015, 05:48 AM
#25
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Eric, Thanks if it wasn't so loose and contacting/hanging up on the dist I wouldn't be worried about it. I'll try to pull it this week and see if I can do anything to tighten it up and get it to clear better. Earlier you mentioned replacing grommets to tighten it up, where can I find them? Thanks for the info on the exhaust. I know some engines run better with X pipe crossovers, some with H pipe crossovers and some with no crossover. What makes a typical SBO happy?
June 29th, 2015, 06:11 AM
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Google X vs H pipe and you'll see that the 2 do different things in gains. Its all about what your after. The other thing is sound each is unique, go to some car shows and listen to peoples exhaust notes and duplicate the sound you like.
This is usually found at the carb side and can be had at your local [arts store in the help aisle, the other side look at what you need to do to reduce the slop:
This is usually found at the carb side and can be had at your local [arts store in the help aisle, the other side look at what you need to do to reduce the slop:
October 12th, 2015, 07:48 AM
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Well I finally got it running fairly reliably, it could be better but it's good enough until I get an adjustable timing lite and replace the distributor cap. I had to replace the carbon button in the distributor and downsize the carb. It had a Edelbrock manual choke 750cft, I picked up a use electric choke Edelbrock 600cfm and tossed it on there. It still has an occasional miss, especially when cold, I think is being caused by carbon tracking in the distributor cap.
There are two things of concern that have come up now that I'm driving it several days a week. First when I park it over night in my driveway with the nose higher she smokes a bit when I first start it in the morning. If I back it into my driveway so the nose is lower then it does not smoke. I'm thinking the valve seals on the rear cylinders are wearing out, what do you guys think? Second is the oil pressure, after I changed the oil standard 10W30 the oil pressure when hot is around 10psi when idling around 650 to 700rpm, when driving it is up above 20psi. Should I be concerned? I won't be racing it any time soon, it will just be used to get me to and from work a few days a week with an occasional run to town @ 75 or so.
There are two things of concern that have come up now that I'm driving it several days a week. First when I park it over night in my driveway with the nose higher she smokes a bit when I first start it in the morning. If I back it into my driveway so the nose is lower then it does not smoke. I'm thinking the valve seals on the rear cylinders are wearing out, what do you guys think? Second is the oil pressure, after I changed the oil standard 10W30 the oil pressure when hot is around 10psi when idling around 650 to 700rpm, when driving it is up above 20psi. Should I be concerned? I won't be racing it any time soon, it will just be used to get me to and from work a few days a week with an occasional run to town @ 75 or so.
October 12th, 2015, 08:13 AM
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Your low oil pressure may be due to the engine being a bit worn, you can up the viscosity on the oil. Also, you need to run oil that has the older friction package like Valvoline VR1 or equivalent. The smoke is probably condensation, valve guide seals don't care what angle the car is parked.
October 12th, 2015, 08:34 AM
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One thought about leaking valve seals, if the oil drain back holes are plugged towards the back of the head, it will allow the oil to pool on top of the head and drain a little through the valve guides overnight. If the drain back holes in the front are more open than the back, then it would drain a bit faster leaning towards the front. That would explain the parking situation. If so, it's a simple fix, just open the valve covers and clean the holes. Mine had old pieces of the broken umbrella seals blocking the holes in the back.
October 12th, 2015, 03:14 PM
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Thanks, I'll check the oil drain holes on the back of the heads. What weight oil would you guys recommend? Something like a 20W50? Idle is smooth and strong at 650 - 700 with the exception of a random miss. When I pulled the cap to replace the carbon button I saw what looked like tracking on the inside of the cap so I'm hoping that is the cause.
October 12th, 2015, 03:31 PM
#34
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The current oils don't have a friction pkg for flat tappet cams. This is a long read but a lot of good info:
https://540ratblog.wordpress.com/
https://540ratblog.wordpress.com/
November 19th, 2015, 08:33 AM
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Well I haven’t gotten a chance to pull the valve covers andclear the drain back holes but I did get a new distributor cap and rotor. Man what a difference. The miss is mostly gone and she will now spina tire from a stop, gotta love open diffs. When cold she stillwill miss or sputter a little it is barely noticeable. Could the coil be causing that?
November 19th, 2015, 06:13 PM
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It puts a smile on my face every time she fires up. The slight miss is not just at idle, it willdo it through the rpm curve but usually goes away as she warms up. When cold she does fire right up but like alot when hot if she sits for more than 5 to 10 min I have to floor it whilecranking to get her started. I’m prettysure I need adjust the floats, I saw some fuel dripping out of the primariesthe other day after shutting it off. Then today after parking it for about 20 when she was hot I cranked herback up pulled out into traffic and floored and she bogged like she wasflooding out, I let off for a sec and got back into it and she was fine.
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