Hey Gang, I just finished building a SBC for my Roadster. Fresh machining, all new internals, fully balanced, flat tappet cam. I'd like to break it in on the stand before it goes in the car. I'm thinking of pluming the garden hose to the water pump inlet and putting a ball valve on the effluent side to slow down the flow. I'll also have a large air mover (meant for flood / fire restoration) pointed at the engine. Is there any good reason not to do this, or should I go the extra mile to get a radiator/ coolant in place? I found a some break in threads, but not any specifically about cooling via house water. Thoughts?
I wouldn’t do that. I’d be concerned about proper water pressure and the fan won’t do much for cooling unless you have a radiator. I’d also wouldn’t break one in without monitoring the temp.
^^^^^ I second that opinion. I use a break in stand with a radiator, gauges, etc. If that isn't available, a shop with a dyno can break in and tune for relatively little cost. Think of either option as cheap insurance.
I’ve done it. No belt, just water flow from hose. Never got to temp ever (had temp gauge to it and a gun). Wonder why?
I like my engines to come up to a normalish operating temp during break in. I'd plumb in a radiator, thermostat and cooling fan.
Thank you for the ideas and feedback. I should probably clarify that I'm mainly looking to do the initial start up, break in the cam and check for any major leaks before it goes in the ch***is. I suppose a true "engine break in" would need to be done on the dyno or by driving the car under load. I've got several good radiators / fans and have the ability to modify my stand to my liking. Sounds like I need to get cutting / welding and get a proper cooling system set up.
It can Be done Like Op wants, No different then Boat set up as long as you know what your doing & pay attention
I wrestled with this also, and decided on the radiator route so I could confirm that the thermostat does its job. Put a piece of *****hose made into a sock in the radiator inlet to catch the rust flakes out of the block. I modified my engine stand to do this, and have a tachometer, and mechanical oil and temp gauges. Think safety on the fuel supply and protection for rotating parts, plus rigging up a temporary exhaust system with mufflers so you can hear the engine.
There is something else to consider. A fresh engine needs a load on it to break in properly. If you are talking about 20 or 30 minutes to break in the cam, fine, but no longer than that. Do it right; put it in a vehicle and get it on the road. Vary the speed and load and you will be rewarded.
Boat setups are designed so that there are no spots in the cooling system where there might be an air pocket. I don't have any photos handy but when I was teaching automechanics we built a number of test stands that we had different engines in. One had a 289 Ford that Ford had donated years before and one had a V8 out of a Chevy Monza that GM donated after it got damaged on a convoy truck. We also had engines that the first year kids rebuilt in cl*** each year and rotated them out when the next cl*** did theirs so they could run them and then use them for other phases of the cl***. The radiators in all of those were what ever came out of a donor car that had a usable radiator. It doesn't have to be fancy, it just has to hold coolant, hopefully have inlet and outlets that match the engine and keep the engine cool .
The advantage of an engine run stand is that it’s a lot easier to fix issues on the stand, than in the engine compartment. If it was a used engine, I wouldn’t hesitate to fire it up with a hose and no radiator, but I feel a fresh engine needs to run with the system under pressure and at operating temperature.
There was a time No break in , Installed & went Racing , But any little helps , & depends on your ring pack , We all have different ways of doing , I have seen Expensive Engine blow up on break in No pulls
Use a radiator on your break in stand. You can start a junkyard engine sitting on a tire, with a hose and starting fluid, not a new build. Ask the machine shop if they will warranty anything that doesn't go right during the break In when you tell them a hose was the cooling system.
The boat comment should give you a little confidence in using the hose. I had an adapter fitting I would install, hook up the hose and fire it up. Never hurt anything. But for your setup, I would connect the water pump inlet to a reservoir of some kind (I have an old 32 gallon well tank with the top cut off for my setup) and dump the outlet hose into the top. The pump will pull what it wants. You can regulate the temperature by adding cold hose water to the reservoir and draining out hot water if you want. It’s about the same amount of effort to rig up fans and a radiator but you won’t overheat with the reservoir system, you could with a stationary radiator and a fan.
I broke my 355 in on a garden hose. I did not do it out of choice. I fired it, had a crack open up on the p*** head in the combustion chamber on number 6. I don't like to stop a cam break in once I am started so I plugged a garden hose into the radiator and broke my cam in. Then I shut her down, pulled the heads and dried it out good. Replaced the heads and have never looked back. That was 1997, and 150K plus miles ago. I do not recommend it but you do what ya gotta do.
I broke in my 250 using a garden hose for cooling, I used a valve on the outlet to control the temp of the water. I had gauges for oil and water, and kept it just at thermostat temp. Just be sure to run the hot water across gravel or driveway, gr*** didn't like it very well.
I'd worry about it never reaching operating temperature and/or inconsistent temperature and zero system pressure. These issues will result in air pockets & bubbles causing hot spots, temperature fluctuations, and steam pressure building up in spots where the air is trapped, that in turn leads to cavitation which can cause major problems to the block/cylinders/heads Yes, it has been done, and can be done, but it's not much more effort to get the cooling system set up to make sure you're covering all the bases.
I use a 20 gallon barrel with a bottom outlet to the water pump and top hose for a return. Run the engine until the water temp goes up, which is quite a long time, and have never had a problem.
The boat comment should not give you confidence. Depending on a few factors you can ruin head gaskets doing this, as I've done it myself. The pressure is a no no. If you do wanna do it this way, run hose into a bucket and then from the pump, and put the dump in the bucket, etc. I have a tank I made for winterizing my inboards, and I run the same system. Hose from tank goes into a bucket via a online pump, hose from bucket to water pump, catch exhaust in tank, and let it cycle until the thermostat opens, and voiala, winterized motor.
That setup is pretty ingenious! Boy am I spoiled living in an area that never gets snow. I'll plan to just get the radiator set up on my stand. Thanks!
Here's the setup that I ended up building. First fire up coming soon! IMG_2016 by Cali4niaCruiser posted Oct 24, 2023 at 7:53 PM
Glad to see you did it right. My 2 cents for others reading this, Fresh engine? Build a darn rad stand. A couple 2X4s should hold it up, if you blew all your money on the build. 1. You have enough things to eyeball and adjust on a fresh engine. This juggling water flow and mess would be one less. 2. A fresh engine tends to run warm, better to test all components together before install. 3. As it warms up, an engine gets fed warmer and warmer water. Constant cold inlet is not the best even without any air. Yeah, boats - I don't care, this isn't a boat forum. Do you really want ground temp water around the cylinders the whole time while breaking in the rings? 4. Depending on where you live, you may or may not run hose water and coolant. At the prices of today's builds, I'd prefer using distilled and coolant instead of my well water. Your water may vary. With the rad setup, drain, save and reuse. You even know exactly how much, so another thing less to worry about when it's getting installed unless you also have a heater.
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