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Good day everyone,

I have previously posted questions with regard to the project described below, but honestly did not get seriously committed to getting to the bottom of issues on this project until 2020. In what follows, I’ve tried to provide a very brief history and a Reader’s Digest abridged version of events as background of where I started and where I am as of yesterday. I’m frustrated and dejected with everything that has happened. I’m looking for any insight that the community might be able to provide as to where to go from here. Kind of at wits end! Thanks for anything you are willing to offer.

Project Vehicle: 1954 Convertible Coupe
• Engine: 359 L8 S/N M603895 with aluminum head
• Purchased: 2003 Reno, NV for $3,000.00
• Condition: Complete car; visual appearance good given age and storage conditions; engine was not running and no history/recollection by owner of last time it did; odometer reading ~51,000 miles

Donor Vehicle: 1954 Patrician
• Engine: 359 L8 S/N M603686 with cast iron head
• Purchased: 2004 Anaheim, CA for $1,000.00
• Condition: Complete car; visual appearance fair; engine had been recently overhauled with less than 500 miles on overhaul per owner’s recollection, but no records found for overhaul or where performed.
• Drivable, but not reliable. Non-starter after hot due to what was, years later, determined to be heat-soak effects on the starter weakening ability of Delco starter to turn over the engine. Engine eventually pulled for Project car. Patrician sold to an interested party in Kentucky sans engine.


Original plan in 2003: Pull engine from donor vehicle and install in project vehicle. Engines were swapped in 2004, however, due to issues with non-start condition when hot due to effects of heat-soak on starter + other life obstacles, I lost interest in the project, so it sat.

In early 2020, after retiring, I was determined that I was either going to find someone that would be willing to work on the engine or sell the car. A Hudson owner at a local car show referred me to a shop that he felt has a good reputation for working on 50's era cars. The opened a dialogue with the owner and he agreed to go through the engine and provide his diagnosis of what he thought the problems were. Bottom line, after getting the engine started and checking compression, etc., his opinion was that there were more serious issues with the engine than heat-soak and he had no interest in digging to the bowels of the engine as he no longer had any interest in overhauling engines, especially those of orphan cars. So, back into the garage it went.

In early 2021, via some networking through a mutual acquaintance, I found a mechanic whose experience was primarily in 21st century modern cars, but had some limited experience on 1950's in-line 6’s and V8's, but no experience with straight 8's. He was extremely interested in learning and was willing to do all work free-of-charge provided I did all the leg work in getting parts. He knew he had the automotive contacts to do whatever machine work that might be required. So in February 2021, he proceeded with pulling the engine and digging into it.

The first obvious issue found with the tear-down was a bent valve. There were also a couple of random nuts found in the block, none of which were from anything in crank case. There were 3 cylinders that had been previously sleeved. He sent the block to be cleaned and magna-fluxed at a local shop that has been in the business of rebuilding engines since 1977 and has a good reputation with the local hot rod community. Magna-flux identified a few cracks and this shop’s opinion was the block was not worth trying to rework. They felt that installing new/additional sleeves might cause the block to literally crack in half. So with that diagnosis, we turned our attention to the project car’s engine.

The block original to the convertible/project car was disassembled. The block had 3 cylinders with sleeves. After further analysis, one additional sleeve was needed, so proceeded with installation of the needed sleeve. After the sleeving was completed, a pressure test was performed on the block with no leaks evident. Therefore, he believed the block to be viable to proceed. It was decided that the pistons were re-useable with new rings (.010); crank was ground/polished (.010); new rod bearings and main bearings installed; aluminum head was cleaned and inspected and found to need several threaded inserts for spark plugs; complete valve job performed; new timing gears/chain installed; oil/fuel/water pumps rebuilt; replaced Delco starter with Auto-lite. Re-assembly and installation in the car was completed in June 2022.

So, the day finally arrived on a warm, late June day, to see if all the work that had been performed over 17 months was going to pay off!! The carb was primed and, after several attempts, the engine started. Everything seemed to be going fine until things reached (or exceeded) temp and coolant started leaking via numerous locations, but mostly through several of the head studs. Needless to say, there were some very dejected faces standing around the car that afternoon.

The engine was pulled and disassembled and everything examined. The post-mortem performed revealed the following issues:
a. Pressure test revealed some minor leaks at 2 of the old cylinder sleeves.
b. Old head studs were used and not installed with any thread sealant.

Fast forward to March 2023. The engine reassembly has finally been completed using new head studs (purchased from Kanter’s) installed with thread sealant. All new head stud nuts installed and torqued as indicated in the service manual. (The engine sat for a couple of days before attempting start-up, so stud nuts were re-torqued before start-up. Nothing had changed.) New head gasket installed as well.

(I forgot to mention that after the failure of last summer, we fabricated a run-in stand so we could start the engine without it being installed in the car.)

With everything ready to go, we cranked the engine and after getting some short start/stalls, fuel started flowing through the fuel pump/carb and she took off. Timing and carb needed a bit of adjusting and the windshield wiper vacuum port needed to be plugged, but then she smoothed out and sounded pretty sweet. We let her run for a few minutes then shut everything down and re-torqued head stud nuts. A couple of the nuts moved ever so slightly. We fired her up again. Running at low idle, things seemed to be going well and we were hopeful all was good, but, alas, they were not. Temp was continually rising and a digital temp gauge indicated a temp over 210F. Temp was hotter at the rear of the block versus front, but was still over 180F in the front. We then noticed steam/bubbling coming from 3 or 4 of the head studs. My recollection is that all leaking studs were on the non-manifold side. As we did not want to continue given the temperature situation, we shut everything down and stopped for the day.

Other items of note related to this week’s events are:
a. There was no leakage around the entire perimeter of the head gasket at the head/block interface.
b. There was no white smoke coming out of the exhaust.
c. Although thermostat was relatively new, it was removed to ensure unobstructed flow of coolant.

I guess I’m looking/hoping for anyone’s thoughts/opinions/theories on the over-temp condition and why it appears head studs are leaking even though threads were sealed. Any suggestions would be welcomed as, at this point, things are at a standstill with no clear path forward!

Thanks much!!!

Presuming the block was hot-tanked and thoroughly flushed, was the brass coolant distribution tube removed first, inspected for damage, then reinstalled afterward?

I'd run it through a few more heat/cool cycles and retorque the head again. If you are still getting leakage at the studs then I buy a package of those stopleak tablets they used for some GM engines and toss them in.

As far as the temperature goes, of course you must have your distribution tube. Beyond that, recheck your timing as retarded timing makes a lot of heat on those engines. What do you actually know about the radiator you are using? How close is it mounted to the fan? Do you have the two heater outlets "shorthosed" together? That causes a lot of coolant to bypass the radiator. Put a clamp in the middle. Also, this is a high friction engine and on break in it will make a lot of heat. I suggest getting a real thermometer and sticking it in the radiator neck to see what you are really getting.

Thanks for your reply Don. I cannot answer your question regarding condition of the diary tube, but I know that it is installed in the block as I asked what it was for during water pump installation.

Mark

Thank you for your reply, Ross!

The brass disty tube is in place, but I did not see its condition.

We did just run a hose between the two heater ports (water pump and head). Will clamp it off in the middle.

The radiator is probably smaller than the newly cored radiator but about as thick and has an electric fan attached to it that we are running off a 12V battery. We considered that might be a contributor to the heat, but got concerned when we were seeing 210+ with the digital thermometer.

We’ll try a couple more cycles with retorquing, the thermometer in the neck of the radiator and the GM stop leak pellets.

Thanks again!

You might want to consider putting the thermostat back in place. Running without it can cause the coolant to flow through the radiator too quickly to cool sufficiently and lead to a hot running condition. The thermostat restricts the flow, enabling the coolant to spend more time in the radiator to cool off before being drawn back into the block.

I agree with all of the above.

As an additional note, when we started up the newly rebuilt engine on my dad's '38 for the first time, I noted that there was some "bubbling" around a few of the head studs after the initial warm up. The head bolts were all new, all sealed, everything torqued to spec. It did not look like coolant. I believe it was residual oil from machining that may have been getting burned off. Regardless, I never saw it again after that first run and the engine has been through many heat/cool down cycles, with the head retorqued.

I'm sure yours will get worked out and everything will be fine. It'll be nice to see your car back on the road.

-Kevin

Like Don said, leaving the thermostat out can actually make the engine run hotter, I believe to be because the coolant as too much momentum to diffuse throughout the radiator properly. Eventually I plan to run a fluid simulation to test my theory on this.

At least once, reinstalling the thermostat with no other changes, cured a heating problem. Since you have such precise equipment, it would be interesting to compare the two heating curves with the only difference being the thermostat.