[1948 Pontiac Streamliner 8]

Ok. So after I spent a couple hours flushing the block really well and slapping it all back together, I started it up. It took too much to start, so I went to look in the engine bay. There was water around the plugs from the work I did and it showed bubbles around 5/8 plugs. Tightened them down and bam, quick starts and smooth running. I took the same circuit I did the other day, with considerable improvement on the temp gauge. Holds at 180 till a long light is hit, then it’s hard to get back below 190. I’m gonna call it a day with some antifreeze and setting the timing with a light, the heat here is just unreasonable.

[1948 Pontiac Streamliner 8]

@Bloo, it’s brass and the tube itself is in fantastic shape- you’re right, only one way it can go in. There was quite a bit of crud in it. Also the head was blocked off around the back where the temp sending unit goes in. Petcock on the block didn’t flow either. Quite a bit of crud in the block. Buttoning it all back up now. 

[1948 Pontiac Streamliner 8]

Getting somewhere. One pop on the ground you did a nice little pile of rust on the water distribution tube. I’m also wondering if it wasn’t put in upside down? It seems like the bigger holes should go to the cylinders to allow more water flow around them from the pump. The picture of it sitting on the bike is the way that it came out

[1948 Pontiac Streamliner 8]

@r1lark, that was my first question when I dropped it off to the radiator man (do I need a recore) because I’ve dealt with that problem on a couple of much older cars. It’s funny because he had also been doing rads over 50 years and the very first thing he did was stick a hose in and turn it on, we waited 10 seconds before water came out of the lower tube.

When I picked it up, he said it was the best rad he’d seen in about 40 years now that it was clean and it would cool anything. He may be my next call.

I appreciate the dialogue and I agree about outside of the box. That’s why checking up in the block is next up!

[1948 Pontiac Streamliner 8]

@SeventhSon, considering I’m consistently getting over 30° higher than I want to be, I’m thinking deposits aren’t the problem. Also, reading on ultrasonic cleaning, it is much better on deposits than rodding and probably equal or better than chemical flushing. Just scientifically speaking, not opinion.

Straight water is the best coolant for heat transfer, coolant just keeps it from easily boiling or freezing. I am going to add antifreeze for the anti corrosion benefit but I can’t justify spending on coolant while I’m still trouble shooting and draining and filling back up. 
If anything, I feel like it’s running a little lean. The choke had to be adjusted toward the richer side to get the idle to smooth out. Choke opens up appropriately as engine heats up, so definitely not rich at operating temp.
Today I’ll take off the water pump and radiator to see what is going on with the main part of the water jacket and check the condition of the water distribution tube. The pump got moved water strong enough to collapse the lower hose when the radiator was blocked but that doesn’t mean the water distribution tube isn’t bent up and impeding flow through the block. I’m leaning toward a mechanical obstruction in the block… I don’t think the timing could possibly be that far off. But will use a timing light later to check.

[1948 Pontiac Streamliner 8]

@Bloo, backfiring isn't the best term (one who is working the night shift shouldn't attempt daytime conversation). There is a misfire (loud popping) on deceleration from higher speeds. I'm trying to figure out of it's a timing, mixture, or transmission issue.

[1948 Pontiac Streamliner 8]

23 minutes ago, Ben Bruce aka First Born said:

Radiator is clean as a whistle!   How do we know this?     Classic  plugged radiator problem.

 

  Ben

@Ben Bruce aka First Bornsee discussion several posts prior. Radiator, which was badly plugged, put through ultrasonic cleaner by a professional. Water runs through like it’s falling through air, no hot spots by IR thermometer.

[1948 Pontiac Streamliner 8]

Alright gentlemen. Manifolds surfaced, new gaskets placed. New plugs.

Outside temperature: 91°F, feels like 103°F

Humidity: 65%

I idle about 3-4 minutes, up to 110. I drive around about 5 minutes, up to 180. Down the road for a few minutes at speed, 190. A couple more, 200. Coming down from speed after the engine heats up, it still is backfiring even though I’m pretty confident there’s no vacuum leak. 
Idle for 5 minutes in the driveway, nearly 220.

Never lost any water, but I am running a 10 or 15 psi cap? I knocked it off from a distance and of course lost a good bit. I was running straight water for the time being.
This engine is fully rebuilt, bored 30 over. The radiator is clean as a whistle. Water pump is rebuilt. No thermostat right now. The timing is set. Points are new and set. Condenser is not new, exhaust system is not new. 
As has been shown, a Pontiac L8 can handle Louisiana heat. What am I missing here? I’m pretty frustrated by the fact that I can’t drive this thing down the road when it gets hot outside.

 

[1948 Pontiac Streamliner 8]

Of note, on my drive today (which was after a long idle up to about 160°), I did not get above 180 after I cleaned up my points and retarded timing a small bit. Just went back out to test my wiper motor; there is absolutely no vacuum in the line so the leak must be huge. Sadly. Did get an IR thermometer. Here’s the readings, in pictures.

the gauge read 150°ish and the top tank read 150°. I’m really surprised at the accuracy of the original gauge and sender. Is this temp drop of about 20° pretty good between top and bottom of the radiator? 
Passenger front door panel finished and on today- only one more door to go. Rubber for tack strips, more vinyl for seats (just hog nails, no sewing for now), new manifold gaskets are on the way. Hopefully I can get acme on the phone and get windlace and headliner in the mail too.

[1948 Pontiac Streamliner 8]

Today I went through my ignition and played with timing. I had some grease build up on my points and scraping that off seemed to help. Put a new cap on the carb choke control too.. I tried adjusting idle air screws and they didn’t do anything. Sure enough, took it for a drive and it was backfiring on deceleration and dying at lights. So, it is time for me to take my manifolds off and have them surfaced by a shop I trust more than the last one, who clearly did not do the job despite me paying for it. I’ll get new gaskets on the way too, third time’s the charm.

[1948 Pontiac Streamliner 8]

@SeedeeI first clean as much grease off as possible. Then change and have a drink, maybe some food. I used a heavy floor jack to jack the A-arm up, take off tire if it isn’t already, place a jack stand or two under the front of the car, unbolt the bolts holding the arm and jack up/down to where they can slide out. Slowly let down the jack, the spring has a lot of energy behind it. Eventually it will be decompressed and out. I kept the jack where it was and put  the new spring in its groove (on one side, oops) and then start jacking. It may take several tries to keep the spring in its groove on the lower arm and in its retainers in the upper arm. It is possible, and not that hard. But be careful that you aren’t jacking a surface that will slip.

[1948 Pontiac Streamliner 8]

@95Cardinalno thermostat right now, no shroud originally. The space between the blades and the rad is not very much at all. A half inch? Haven’t measured. Don’t have a thermometer but will borrow one when I have time and also probably hook up a capillary thermogauge to check the electrical unit. 

@Bloo, I appreciate all of your suggestions a lot. I’ll go with @Grimy’s filter idea, even if I don’t use a stocking I like the principle of not fouling my radiator.

As far as thermostats, I did find one that fit snugly, but upon taking it out it did not fit. As for the water distribution tube, I’m almost certain I have a brass one in. 
The ultrasonic cleaning is really interesting conceptually, and it’s not uncommon. This guy is here in northwest Louisiana so I can assure you if we have it, lots of cities do.

Something I noticed yesterday while driving: misfiring on deceleration from speeds of 35+. 
This drive saw the temp hold steady at gauge 180, a stop at a long light got me nearly to gauge 200, but that decreased a bit after driving and stayed gauge 195-200 till parking at home.

[1948 Pontiac Streamliner 8]

The man who did this clean out said he’s been radiator cleaning, building, repairing for over 50 years. He says that he has no reason to rod any kind of heat exchange core due to his having an ultrasonic cleaner. Scientifically, this makes since. Rodding removes large debris but doesn’t remove mineral deposits. It also creates risk of rupturing a tube. Less invasive is always the way to go- water literally falls through this radiator now. If you pour a cup in, it will start pouring out of the bottom tank as fast as you can pour it in. 
Like I said, I haven’t trialed the radiator much, but my suspicion is that it is not an issue anymore. 

[1948 Pontiac Streamliner 8]

@Ben Bruce aka First Bornthe radiator was put through an ultrasonic cleaner made for radiators. I would have to imagine this is the most effective way to clean a radiator. Water runs through it so quickly I doubt there are any blockages now. One thing you said and one thing I forgot to mention but am aware... I still don’t have a thermostat since taking out my faulty one. I’m thinking now that the water is running quickly through, it really may need to be slowed in the radiator by a thermostat. 

[1948 Pontiac Streamliner 8]

Spent the day getting my cleaned out radiator and my new gas tank with sending unit in.

I cut out must of the rusted vestiges of the trunk floor... they really don’t make a pan close to this so I guess I’ll have to. 
The radiator does a good job, but I’m still creeping up toward 200° per the gauge when I’m sitting at the driveway and backing in after a drive. I’ll give it a good test tomorrow, put some antifreeze in there. Gas tank is great, sender is accurate on the gauge, couldn’t be happier to not have to open the trunk to put gas in! Going to order tack strip and windlace soon.

[1948 Pontiac Streamliner 8]

@Bloo, thank you! That’s the missing piece. I appreciate you so much, that gives me the confidence to go ahead and do my headliner. I’ve been scratching my head for months.

[1948 Pontiac Streamliner 8]

@Bloo, there is a rubber rack strip that is held into the body. I still have windlace nailed into it. My question is, after the windlace is stapled on, you can hang the headliner on the bows, even tuck it behind the windshield molding, but how does one tack the headliner edges along the windlace without the staples or tacks showing? Do you just get the staples in right behind so the round part of the windlace hides them?

[1948 Pontiac Streamliner 8]

Ok. I got the radiator put through an ultrasonic cleaner by a man in the industrial district by downtown... he looked at least as old as the car, coveralls, complete with a red embroidered name tag in that classic cursive: “Eugene.” 
He said, “That’s the best radiator I’ve seen in 40 years.” When asked did it have junk in it: “Ohhhhh gaw I don’t know how any water flowed through it. Cups of sludge came out.” 
Sure enough it was noticeably lighter on pickup. He soldered me a slightly shorter neck for my modern cap and re-affixed the overflow tube, which was wobbly. I have to paint the tanks again and reinstall, but I’m sure things will be cool now and will update after install.
 

Now, gentlemen, I’ve scoured the web. HOW does the Pontiac headliner for 48 install over the wind lace?? As far as I can tell, there is no tack strip, but there is the rubber the wind lace staples into... is there a fisher body manual for these cars? I’m perturbed. Ready to paint all the metal, put insulation on the roof, and slap a headliner in.

[1948 Pontiac Streamliner 8]

@Ben Bruce aka First BornI do mean rodded or sonic cleaning, if I have time tomorrow I’m taking it to a shop to see how much.

[1948 Pontiac Streamliner 8]

@pvfjr have fun, it's a great car to drive around in. My inbox is alway open for questions.

 

I've resolved to get my radiator professionally cleaned, I've been reading around and the lower hose collapse may be a symptom of blocked radiator flow. Until I do that, I won't fool with the thermostat. If radiator clean out doesn't work, I'll pull the thermostat for a bellows type, then check on the condition of my water distribution tube.

[1948 Pontiac Streamliner 8]

@PhilAndrews it took me literally months and I found this by accident, but it can be done. They sent me my updated registration with the new license plate number attached now to my vehicle after I sent in my paperwork. I was about to just get a custom plate when I found this hyperlinked to another form. If you have any questions, you of course know how to reach me. ‘51 LA plates are easier to find than ‘48!

[1948 Pontiac Streamliner 8]

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!

[1948 Pontiac Streamliner 8]

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.

[1948 Pontiac Streamliner 8]

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.

 

[1948 Pontiac Streamliner 8]

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.