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1948 Pontiac Streamliner 8


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I changed out all my spark plugs. They needed it. However, I think we’re getting fouled up still. Those are the plugs I’ve been using since rebuild through trying get the timing right, adjust the carb, when I had the wrong distributor on etc... I’m wondering if the carbon didn’t build up on valves too. It stumbles when I try to accelerate quickly from idle, but drives great. No overheating. 

The only other thing I can think of is a leak at the manifolds or a faulty vacuum advance. The timing is right.

Would it be worth it to take the head off and get a new gasket just to clean the carbon build up if an oil change doesn’t really change things? I know the oil is terribly tainted. The expense may be worth it, the engine is totally rebuilt otherwise.

anyway, that’s my update! A lot of rides given today, a lot of happy faces. Although some snooty guy did ask if I “lost a bet” or got “paid to haul it off someone’s property.”

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I think I'm decided on an oil change for now. There's definitely gas in the oil and it's about time for a post-rebuild change. I can clean the new plugs again and see where we're at after. A new condenser in the distributor and a drive shaft/engine mount tightening would be good too. There's a car show down the street next Sunday, I may hit that up.

Edited by cevensky (see edit history)
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22 hours ago, cevensky said:

I changed out all my spark plugs. They needed it. However, I think we’re getting fouled up still. Those are the plugs I’ve been using since rebuild through trying get the timing right, adjust the carb, when I had the wrong distributor on etc... I’m wondering if the carbon didn’t build up on valves too. It stumbles when I try to accelerate quickly from idle, but drives great. No overheating

those plugs show unburned gas and no signs of oil fouling which is good news.  I would not pull the head.  Even if it did have a lot of carbon, there are products like GM made to pour down the carb hot, then run it hard. I doubt it has a lot of carbon.

 

Unburned gas is typically ignition related, but on vintage cars it sure could be carb related.  You will just have to keep at it, like changing condenser, checking the advance, etc.  A very skilled person could probably tell what's wrong in person, or have a good idea of what's up.

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  • 2 weeks later...

Well today it happened: the car quit unexpectedly for the first time. Kind of strange it held out on me so long!

I was coming to a stop sign and talking on the phone when I heard it start to die out. Felt like the gas had run out. 
I ground on the starter with various combinations of choking, stomping the gas pedal, checked the gas (not a ton, but certainly enough). About 30 minutes later and puffs and spits of gas up out of the carb, we decided it was a much-too-rich mixture. I forced the choke open and sped back home into the garage (I was on my way to get gas, then to a park get-together, so I was close).

I let it idle about 15 minutes a little high to burn off a bit of what I’d done.

Oh, and then I opened the hood and the top bar of the grill fell off 😂 but that was purely my fault. 

Looks like it’s time to take the whole carb apart and clean some passages. Likely culprits I think will exist in the bypass passage in the low-speed system, and in other passages that allow air into the mixture moving through that I have yet to identify. Any WCD experts?

Edited by cevensky (see edit history)
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  • 2 weeks later...

This weekend we had a little cruise in at a restaurant near by. Lots of people liked talking with me about my Pontiac. I tried some clear coat and repainting the hood. It runs easily, so I’ll see how it takes to sanding after it cures some.

All in all it drove well, I cleaned up some of the trim, and put on the last missing piece of door trim. The overall optics are pretty good and I haven’t got the energy for any more painting, so I’ll finish up wiring brake lights and turn signals soon. If only all the paint turned out as good as the passenger side.

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  • 2 months later...

One day over break I was running my engine in the late daylight hours and was able to see my manifold gaskets were letting fumes out (illuminated by the sunset hitting horizontally). The engine also gave god awful vibration at midrange RPM. 

The new gaskets arrived, I put them in very carefully and with extra sealant and the like. New exhaust flange gasket. 

It drives like a brand new car now. At least 50% more power. It makes sense. But I’m still amazed. Got a blinker wired, working on upholstery, and now considering the $400 for a new exhaust system to get rid of the cut and split dual exhaust. 

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I forgot that I also replaced the collapsed driver side coil spring over break with a stock size spring- I haven’t had the heart to do the passenger side yet because it involved a lot of scraping and wire wheeling of very heavy grease buildup to get to the hardware. A 2300 PSI power washer didn’t touch this grease. Sits much higher and feels a bit better. I’m sure it will improve even more once I get the other side done too.

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On 10/18/2020 at 10:23 PM, cevensky said:

I changed out all my spark plugs. They needed it. However, I think we’re getting fouled up still. Those are the plugs I’ve been using since rebuild through trying get the timing right, adjust the carb, when I had the wrong distributor on etc... I’m wondering if the carbon didn’t build up on valves too. It stumbles when I try to accelerate quickly from idle, but drives great. No overheating. 

The only other thing I can think of is a leak at the manifolds or a faulty vacuum advance. The timing is right.

Would it be worth it to take the head off and get a new gasket just to clean the carbon build up if an oil change doesn’t really change things? I know the oil is terribly tainted. The expense may be worth it, the engine is totally rebuilt otherwise.

anyway, that’s my update! A lot of rides given today, a lot of happy faces. Although some snooty guy did ask if I “lost a bet” or got “paid to haul it off someone’s property.”

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stumble on acceleration likely is the accelerator pump going bad, be interesting to know which cylinders on the straight eight are producing the carboned up spark plugs

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51 minutes ago, pontiac1953 said:

stumble on acceleration likely is the accelerator pump going bad, be interesting to know which cylinders on the straight eight are producing the carboned up spark plugs

 Charles, pretty much all 8 were. Pump is brand new built for modern gas. It was a mixture problem, big leak leading to over correction with over-rich mix. The back half of my manifolds were not sealing all that well. Something went wrong with my first gasket install. Now we have no stumble but I think replacing with new plugs again now that we aren’t dealing with a funky mixture could improve even more. I’ve thought about buying the foam you run straight in the intake to clean the intake valves. Anyone have experience with this?

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2 hours ago, cevensky said:

 Charles, pretty much all 8 were. Pump is brand new built for modern gas. It was a mixture problem, big leak leading to over correction with over-rich mix. The back half of my manifolds were not sealing all that well. Something went wrong with my first gasket install. Now we have no stumble but I think replacing with new plugs again now that we aren’t dealing with a funky mixture could improve even more. I’ve thought about buying the foam you run straight in the intake to clean the intake valves. Anyone have experience with this?

seafoam is an excellent product for that.

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I wouldn't fault you for using grade 8 studs, I probably would. If your manifold assembly is not perfectly flat, get it machined. It really does matter. The whole thing needs to be able to move at it heats, especially the exhaust. It will grow with heat at a faster rate than the block does. Look down your stud holes to make sure as the manifold gets slightly longer, it wont hit the studs. Ideally  with the engine cold the studs should be near the outside of the holes out at the ends of the manifold. Most cars use slightly coned washers with the high outer edge down against the manifold, not sure about flathead Pontiac, as I have not had my manifolds off. Above all don't use soft washers that can squirt down into the holes and block motion. Also make sure the washers themselves will not block motion by getting trapped between the something hitting the washer's outside edge and the stud as the manifold expands. The expansion will happen. if something blocks it things will break, Maybe studs, but usually the exhaust manifold.

 

Edited by Bloo (see edit history)
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Bloo, I think this was a case of over torquing one of them and it just being old. Also within one day it was warm (60°F), I drove it a lot, and then it started snowing 10 hours later.

I think I’ll be able to drill it out easily. I have all the original washers on there.

 

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Alrighty. After returning home from my ‘15 T project, and working a few hours here, I was able to pull my fender and painstakingly drill out that stud till it fell apart. Was able to find a perfect replacement at my bumper to bumper and now I’d feel safe driving it again after I do some odds and ends that having the bumper off allows me to do. Next week I’ll bring all the required paperwork to get plates and title (there’s no chain of ownership for this car so I have to create a title with the Louisiana OMV). The guy who did the vehicle identification for the paperwork said he could do my trunk floor, bodywork, and paint. He said he’d be reasonable so I’m considering taking it to him if he’ll talk numbers with me. 
My four white walls arrived today, although they are definitely not as portrayed in the pictures, they are much nicer than what I have on, and for $720 for a set it can’t be beat.

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  • 2 weeks later...

Sunday I spent the day wire wheeling grease again to put on the other spring, such fun. It went well (better than the other side) with the fender off and with daylight. I got to paint it all too and do some odds and ends like touch up manifold paint. Moving right along.

 

Quick question: should I have put something on the manifold stud I installed to prevent water coming around it from the cooling jacket? I think it stopped and it may be too late, but figured I should know if there’s a next time.

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Any stud or bolt that goes into a water jacket should have sealer on the threads. Traditionally shellac (Indian Head, Permatex #2, etc.) is used. Teflon pipe dope (not tape) for plumbing will also work.  Loctite makes something similar, intended for sealing bolts and studs. Regular Loctite threadlocker will also work, although it is an off-label use. Whatever you use, the threads should be clean, chased, and dry. Rust, being porous, can allow seepage around your sealer. I usually use Indian Head.

 

Edited by Bloo (see edit history)
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Not sure how I’ll get the stud out but seems like something has happened with my new gaskets and may have an intake leak again. Starting to think they never actually machined my manifolds when I took them way back when. Definitely developed a new exhaust flange leak. Those gaskets never hold up, probably a warped header.

It still drives loads better than it did.

Tomorrow I’ll hopefully have all the new tires on. Here’s a teaser for now.  

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I did get it done yesterday, but not till it was dark. I finally have my title, registration, and I went ahead and bought insurance today, so I was able to do a legal(ish) drive. I’ve applied for antique plates. 
 

The white walls really change the overall car. I guess now I really do have to get it painted...

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  • 2 weeks later...

Eventually I’ll have my manifolds surfaced by the shop that did my engine, with new exhaust system when the money’s there... I did take it out in the rare and historic snowfall we’ve had here in Louisiana. Just across the street for photos, but ran very well and looks good. Oh, what it would be to have five grand to just finish it 😂 

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  • 2 weeks later...

Ben- no remflex for the 8, only for the 6.  Even then, the lateral expansion with uneven surfaces is what I think is driving it. Thick or more malleable gaskets is a bandaid, I’d rather fix it right... that being said I’ll keep remflex in mind on my projects they sell products for 😂 

 

After months of scratching my head, I finally figured out that my turn signal was wired incorrectly. I had two wires backwards, but I have not been able to find a diagram that shows the internal order for the guide 6002 turn signal, which came original as an option with these cars. I’m lucky that I found the original one in the trunk after I purchased the car, the chrome is nearly perfect... and now, it is perfectly cleaned, re-soldered, and all the lights work (front signal pics coming soon, but they’re amber colored LEDs, I went with all LED other than headlights).

Regardless of if you’re going to use LED or traditional bulbs, the LED/electronic flasher that you can find on eBay and elsewhere is loud and works very well. I’m very happy with how clear all my signals are. The LEDs were cheap and they are very bright. Nice safety feature, still on 6v. 


light video:
https://drive.google.com/file/d/1cPMVS_zPSUlH5HUPD1kLEZJyhR65LZRl/view?usp=drivesdk

Edited by cevensky (see edit history)
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On 3/3/2021 at 7:59 PM, cevensky said:

Does anyone, perhaps Charles (I wish we could tag people in these posts), know if the grills for 48 pontiacs are all universal? I found one for a decent price and good condition in Texas I want to drive to get. 

Nice progress @cevensky!  To tag some in a post, type the “@“ symbol and then start typing their forum name.  From there you can pick from a list ...assuming they are on the forum.

Edited by SparkEE (see edit history)
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On 3/3/2021 at 9:59 PM, cevensky said:

Does anyone, perhaps @pontiac1953 Charles (I wish we could tag people in these posts), know if the grills for 48 pontiacs are all universal? I found one for a decent price and good condition in Texas I want to drive to get. 

all 1948 pontiacs built here in the states, used the same identical radiator grill.

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Always prompt with the knowledge, thanks Charles!

I got to come home from school to a license plate waiting on me, which was incredibly hard to get... and expensive.

I sent the appropriate fees and notarized forms to the OMV on Friday and am just awaiting their approval so it can be used in my car as the real plate.

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Edited by cevensky (see edit history)
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I put the trunk handle back on. The handle and shaft are supposed to be held together by a stay screw that allows them to rotate as a unit when the handle is unlocked. All that pot metal is broken so I attempted a jb weld fix, which nearly held but broke due to my manhandling trying to work the stubborn and dirty lock. But anyway. License plate on. Lights acting whacky (issue with the turn signal unit again, sliding contact plate, I think), front driver coil spring collapsed (again. Maybe not installed in the groove? It’ll have to come out and be reinstalled to verify, it expanded when I jacked the car up... Ugh). 
Three steps forward, five back.

 

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Edited by cevensky (see edit history)
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On 1/18/2021 at 11:56 AM, cevensky said:

Well. Looks like I need to do the gaskets again. Dang. Getting this out should be lots of fun. Aren’t studs supposed to be grade 8? It was broken before I even touched it... just sitting in its hole :(

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these manifold studs are exposed to the cooling system coolant in most, if not all locations, coat the threads with grease to prevent thread corrosion.

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  • 1 month later...

Of course a tab broke that holds on one of the hubcaps. But I’ll take it to a friends garage to get it tacked back on. Overall, pretty good. But, it gets hot these days with the weather back above 80. It wouldn’t get above 180 (by gauge) with the weather below 65°. Now I can drive and drive, but any kind of sitting for a while will put me up to 210, which doesn’t come down below 190. Maybe a proper thermostat will help the coolant flow through the radiator slower? Will that really help? I think the one in there now is kind of loose. I need to get an infrared thermometer and see what it really reads on the block at the temperature sender.

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Yesterday I took some time to trouble shoot my rear bulb sockets and tidy up wiring. Then I took a hubcap-holding tab off The spare rim and got it on the front tire with a new rivet. Popped the rubber on my fender skirts and popped them on, didn’t think I’d like them... but dang they look good.

Drove around and got to a cruise-in down the street. Good day, but it feels like I’m losing power somewhere. I checked the plugs the other day and they weren’t badly fouled, color was OK. The intake valves had carbon build up but exhaust looks brand new (I’m pretty sure not vice versa). My top speed was like 47 mph... could that be due to my exhaust leak? I think the manifold is well sealed at the block. Issue is from the big leak at the manifold-to-pipe connection. 
My lower radiator hose collapses from suction created at the pump at higher revs, so time for a new rigid one!

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Edited by cevensky (see edit history)
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