oldsguybry

A while back at a traffic light I noticed a couple times , the engine seemed to cut out for a second like it almost died , and then resume normal idle.... Today at a gas station , it started mis-firing bad for about 4 seconds or so and then back to normal again....I had this car for about 9 yrs and did not drive it much until the last few years , so the only thing I remember replacing was the spark plugs....maybe one of the plug wires is cutting out ? could use a cap and rotor , points possibly too.

Rickman48

Check the timing chain.
Pull the cap, and move the lower pulley back and forth to check play.
More than 1/2 inch in either direction before rotor movement, is too much.
Since you have to remove the water pump to get at it, it's a good time to replace it.
If it should 'jump time' or break while driving, you might be looking at bent valves - many more $$$$$!

oldcutlass

Refresh your tuneup, dwell, timing, sparkplug gap, new fuel filter, carb adj, etc...

oldsguybry

hey guys , I know im being lazy , but does anyone know offhand what the sparkplug gap is on the 72 CS 350 ?......will be changing the plug wires out tomorrow , will post a few pics on various things along the way.

Lady72nRob71

Check points and file or replace if over 10k on them.
If ignition and timing is ok, sounds like you might just need to give it a good run to clean the fuel system out.
If I let mine sit over 4 months, she hesitates on accelleration and coughs here and there. After 50 miles, she is fine...

oldsguybry

thanks Rob , but if it was the timming I would think the car would run like crap all the time ......mine runs fine and then all of a sudden it cuts out for a second and then goes back to normal ....and its been doing it more often lately. I noticed a plug wire laying across the exhaust manifold , so im assuming the plug wires may need replacing and the points for sure.....BTW anyone got the 72 350 spark plug gap dimension?

Lady72nRob71

True about the timing - yours is intermittant...

If that wire is melted, then it could be an issue.

0.040" for stock plugs.

72 w29 all green

.040

oldsguybry

Thanks

Railguy

Don't for get to check the easy things first.Air cleaner,fuel filter,fuel pump,and the dreaded mouse nest in the breather or stale gas.
railguy

oldsguybry

yea , I was thinking about changing the fuel filter too while im at it....where is the fuel filter located originally ? cause on my car its about a foot before the fuel pump from what I can remember , as a matter of fact I may of even replaced that stuff already when I bought the car 10 years ago...air filter is ok still and has no nests in it ( been driving the car quite a bit the last couple of years ) anyhow , we will see this weekend when i get a chance to look at it.

Big Blue 72

You can see the stock location in this post: https://classicoldsmobile.com/forums...tml#post209163

It is in the protruding boss in the front of the carb. There isn't normally one before the fuel pump is there guys? I would think that it would make more sense to have a filter before the pump though, anyone have an idea why it wouldn't have been like this from the factory? Ease of replacement with it in the carb? Personally that rigid fuel line was a major PITA and when I was young and stupid I made the mistake of cross threading it... Definitely was an expensive lesson in patience...

Lady72nRob71

Makes me wonder, too. Threading stuff in the carb makes me uncomfortable.
Maybe it is easier to pump though it vs suck through it??

oldsguybry

1st pic is of part im holding to the right of my thumb , where did this bolt to at one time , instead of just laying on the top of the motor ? 2nd pic is a shot of the fuel pump and filter ....was this the original spot for the fuel filter ? and on the 3rd pic the rubber gas line is slowly melting away because its laying on the thermostat housing....I could probably do away with the metal piece inbetween the carb and the rubber hose with an npt adaptor , that should shorten it up so it dont rub anymore...and all I can say about the 4th pic is..." LOL " ...where did this ground wire on the coil use to bolt to ?

MDchanic

1st pic: Looks kind of like a TCS solenoid - an old and pointless emission control that is better disconnected.

2nd pic: That's an aftermarket fuel filter - fine if it's not full of crap.

3rd pic: That line from the pump to the carb should be steel, not rubber.
Where it goes into the carb is where the factory fuel filter is.

4th pic: The wire from the radio suppression condenser goes to the (+) terminal of the coil, to reduce radio interference.

- Eric

oldsguybry

thanks MDchanic .......I bought new plug wires and the first thing I noticed is the ones that were on the car were way longer than the ones I bought....whoever put the ones on the car used plug wires that were to long , the new ones I bought seem to fit better....as soon as I started the car It seems like the new wires did help a little , but still could use improvement , so im gonna relace the distributor cap and the rotor and points , and inspect/re-gap the plugs.

Big Blue 72

I'd see if you can find a steel line, but I like the idea of a fuel filter in front of the pump. What have other people done to get around the stupid in carb filter set up? If I recall correctly, the trick was to just unscrew both the output from the fuel pump and the input to the carb and then do it in the opposite order when putting it back on to avoid from stripping the carb boss.

oldsguybry

Well first off , the guy at the auto part store gave me the wrong points. The one he gave me had the points and condensor all-in-one ....with no screw on the side to attach the wires to....so I took that back and the guy was digging through a box and then told me he didnt have any. So I went down the road to another parts place and they had exactly what I needed fo half the price as the other one. So I get home and put the condensor , rotor cap , and the points on , only to find out that the gap checker that the guy at the first store sold me only goes up to .025 and I beleive he told me it was suppose to be .040 .....to make matters worse the parts stores are all closed now. So can someone here clarify if the gap is really .040 for the points on a 72 CS 350 ? and then tomorrow i will go ring this guys neck....I mean , I will get the right guage if I dont already find one somewhere laying around....The first and second pic is how toast the points I took out were , and the third pic are the three parts in question

MDchanic

Those combined units should work fine, but there was some reason why they might not be quite as durable as the original type separate points and condenser - I just don't remember why.

A 0.040" gap is a spark plug gap, not a points gap.

The only appropriate response to the parts guy's suggestion of 0.040", and to your acceptance of that number, would be a Three Stooges "Double Slap" or "Two-Head Bang" to both you and the parts guy, and I am sorry that I am not there to administer it [insert coconut sound].

The points gap should be 0.019", if I recall, but you should really set the dwell angle with a dwell meter instead. It's easier and more accurate. Also, how the heck did you expect to set the points with a spark plug gauge?

- Eric

oldsguybry

actually you can leave me out of the three stooges bs , cause im just an innocent bystander that had no idea what the gap was in the first place , if i knew what it was , then i wouldnt ask . .....(cooling off ) I apologize , me and the wife are in the middle of round 10 , so not a very good day so far.... thanks for the gap dimension on the points MDchanic , I always seem to have trouble finding those kids of things in the manuals....it looks like i was wrong then , even though he (parts guy) wrote the wrong gap on the box. I only changed points one other time in my life and i dont remember gapping them lol.

oldsguybry

after all was said and done , the car does seem to idle and run better , I beleive i got the gap pretty dang close if not dead on with the points....I actually used the play in the distributor to get the high point and then adjusted the screw so the .019 guage just slips through , so it should be good. The distributor cap was still good but I changed it out anyway , so all that is left to do is to inspect / re-gap the plugs themselves.

oldsguybry

Hey MDchanic , at least I knew where the points were , and that they needed to be gapped....so im not a complete dummy .....anyhow , I took the beast on the freeway , and mannn , you would never fall asleep driving that car...thats for sure. The car did have an alignment , but still is not freeway worthy , probably because the tires are shot....our 2001 Z24 drives like a dream on the freeway , and then you take the Cutlass on the freeway and .....eeeks. I'm also gonna invest in a TH400 tranny down the road , whether or not I put the 455 in (im assuming they are a 4 speed tranny ), cause my current TH350 is only a three speed and would waste a butt load of gas if I ever wanted to travel somewhere in it at freeway speeds.

1969w3155

The th400 is a 3 speed auto tranny, built originally for the 400/425/455.

oldsguybry

darn.....so what do people usually do ? change gear in tranny or rear end ? or get a 4 speed ? I dont mind the gearing , but like I said it would get better gas milage and noise reduction if I had a 4th gear ....not a must though.

Lady72nRob71

What rear ratio do you have?
Unless you plan some VERY long or frequent road trips, the cost of converting to OD may or may not be worth it. Time to crunch some numbers and see it it will be worth it. My 350 gets a combined 19 during long trips (2:73 rear), so I am not too unhappy, and she gets about 2000 miles a year.

oldsguybry

Yea , im not sure what rear ratio I got , but its a 72 CS with a 350 4 BBL carb and had single exhaust....lol she sounds like she is going to explode on the freeway.

GTI_Guru

If you convert to a 4-speed auto the 200 R4 is probably the most common conversion, but the TH400 is the stronger unit, and I suspect still cheaper to build and install overall, but I could be wrong about that. I haven't messed with these units in over a decade and depending on how many have blown out for drag use in that time, there may be a serious price swing in one or the other unit anymore. I'm sure someone else will chime in if I'm incorrect, but either of those are probably your best option for a replacement trans.

Also, if you're missing the code/tag on the rear end, a floor jack and a piece of chalk can get you pretty close on the rear end numbers. Just mark the wheels and driveshaft, and count the turns. You can probably get it dead on to ID the rear end gear with this method. Make sure the front wheels are blocked really well, and with the rear end in the air, put it in neutral (on LEVEL ground) and spin the rear tires and count the turns on the driveshaft. Guessing it's probably a 2:73 or 3:08 if it's not any kind of performance package or posi unit.

-Jeff

oldsguybry

thanks for the help....I will try that method to see what gear ratio i got .

oldsguybry

1. since I have to swap all the pulleys and brackets with the 350 in order to put the 455 in my car , i did not notice anyone mentioning swapping the big bottom pulley below the water pump and how hard is that to get off ?

2. the 455 sat for 4years in a garage attached to house and it smoked a little before i removed it from Toro , on the other hand the 350 smokes and has a engine knock .....so why not just jam the 455 in there since i have zero dollars to spend on the car this year anyways ? or do you guys think that the cylinder walls may be to rusted up ? what kind of problems may that cause short term ? I actually have another important question , but i forgot lol

oldsguybry

ok , anyone know why the 350 would knock one day and not the next ? I noticed that today driving here and there that there was no knock , even though it was hot out and the engine was fully warmed up......also was wondering , when I lift 350 up to remove oil pan and inspect motor inners , what do I remove besides the motor mounts obviously , so I dont break anything that im not thinking of right now...I only have to lift it a couple of inches right ?

oldsguybry

sounds like i cant make up my mind on what i want to do , dont it ? lol the truth is I need a more reliable transportation , our minivan cant be relied on , so that leaves us with two vehicles left....if something happened to my 72 CS , we would be in a pickle.....also want a car that spins the tire when you push the gas pedal down , I know im getting ahead of myself , but maybe an increase in power would actually slow me down a little.

GTI_Guru

yeah, you are kind of jumping all over the map in this thread. From a minor 350ci tune up to a 455 swap. LOL! The 455 should be a bolt in, and if all the pulleys are on that engine, those are the ones to use. I don't even know if the 350 set will work on that engine, but I doubt they line up once transferred over. The crank pulley is an easy enough swap. 4 small bolts hold the pulley to the balancer. And you'll want to keep the balancer on the 455 with that engine for sure.

As far as reliability... Relying on the Olds as a primary in the shape it's in right now may be the wrong way to go. Did you ever get your rear end gearing figure out?

Small steps are best if you haven't had much experience with older cars. Don't get in over your head and end up with a yard/driveway ornament that costs way too much to get back up and running. If that 350 isn't knocking all the time, it may be something as simple as a loose bracket rattling against the block, or something along those lines. Once a bottom end knock starts, it's not going to "magically" disappear. It just gets worse til you leak a rod.

oldsguybry

[quote=GTI_Guru;280850]yeah, you are kind of jumping all over the map in this thread. From a minor 350ci tune up to a 455 swap. LOL! The 455 should be a bolt in, and if all the pulleys are on that engine, those are the ones to use. I don't even know if the 350 set will work on that engine, but I doubt they line up once transferred over. The crank pulley is an easy enough swap. 4 small bolts hold the pulley to the balancer. And you'll want to keep the balancer on the 455 with that engine for sure.

As far as reliability... Relying on the Olds as a primary in the shape it's in right now may be the wrong way to go. Did you ever get your rear end gearing figure out?

Small steps are best if you haven't had much experience with older cars. Don't get in over your head and end up with a yard/driveway ornament that costs way too much to get back up and running. If that 350 isn't knocking all the time, it may be something as simple as a loose bracket rattling against the block, or something along those lines. Once a bottom end knock starts, it's not going to "magically" disappear. It just gets worse til you leak a rod.[/quo

thanks....I have not checked the rear end deal out yet , but hopefully this weekend , I can peek at the 350 and see if i can start to figure out what the problem is....man , I would much rather put the 455 in there though...I miss having a fast car , since i got rid of the Roadrunner years ago..... I have no choice but to rely on the 72 CS , we only have one other reliable car and my wife carts my kids around in it , leaving me with this car only pretty much...will chime back in on this with pics this weekend.

Shizzy

if the 72 is your daily, I would stick with small improvements to make it more reliable.

I swapped a TH2004R in to my 72 Supreme with a mostly stock 350. I put in a used tranny that came out of a Monte SS. with a stock 350 with only street use I don't see any need for any upgrades to the stock transmission. I have a 3.08 rear gear and the O.D. gear sure is nice. I did the swap as the TH350 that was in the car was in need of a rebuild and I got the TH2004R for only $200 with converter.

keep in mind with the swap you are going to need to figure out how to attach the TV cable to your carb, wire up the TCC, figure out your shifter and install different parking brake cables. again, with a daily driver this is not fun as your car could be down for at least a weekend.

oldsguybry

T.V. cable ? TCC ? not sure what that means....I already got a convertor box for my T.V. he he

GTI_Guru

If you don't know what those terms mean, you're probably better off not making the swap to an overdrive trans. If you want to learn more about it, here's a good thread someone wrote up on that exact swap in a 72 skylark, and will be almost identical to what you're facing if you want to go through it on your 72.

http://www.v8buick.com/showthread.php?t=176591

There may be a similar post on the CO board on how to do it, but I haven't found one quite yet, and this one is VERY detailed. Pretty much covers all the bases on what's required to get that unit installed. The 72 Skylark 350/350 will pretty much exactly what you have in the Cutlass.

-Jeff

**EDIT**

After a bit more digging, I found a similar thread here on CO with some other details as well.

https://classicoldsmobile.com/forums...onversion.html

oldsguybry

hey thanks , I appreciate it.

oldsguybry

I replaced the plugs in the car today , and I think the ones that were in there are better then the ones I just put in....better quality anyhow....Notice how there is one plug that is caked with oil , the rest were ok.....That will be the first place I inspect in the coming weeks when I lift motor to inspect the bottom end.

MDchanic

Those don't look bad.

Who the $#%^ sprung for PLATINUM plugs for that crate???

Wow - talk about having too much money!

- Eric

oldsguybry

....I put them in , I dont remember buying platinum but I did put plugs in 10yrs ago when I bought car....do you think I should save the old plugs ?