Paul of MO
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- Joined
- Jul 2, 2011
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- Land of old Geezers
- My Car
- 71 M Code Convert - Barn find
73 H Code Convert - Field find
73 H code - Latest Project
351C break in procedures and break in oils.
Build the engine
Use generous amounts of assembly lube.
I soak the new lifters in warmed motor oil with a little assembly lube dissolved in it over night.
Do not pre pump up the lifters before you install them – it may hold a valve open during initial startup keeping the engine from starting.
Unless it has a .6 lift cam or higher there is no need to use weaker break in springs.
With the valve covers off use a drill to spin the oil pump - just long enough to see that you have good oil pressure. Once all the rocker arms show oiling STOP – you do not want to wash away or dilute the assembly lube. One great tool to make it to cut the top off a pair of old valve covers to keep the mess down but still being able to see everything.
Some turn the crank by hand one full turn while “drill priming” – I do not, once I see oil at the rocker arms on a 351C I know that everything has been oiled.
Use a known carburetor that will immediately start the engine and run the engine. I usually pull one off of a running and recently driven car to eliminate the unknown carb variable.
Install a known and working distributor and static time the engine. Static timing means carefully setting the timing mark on the damper to about 10/12 degrees with the engine off using a breaker bar to carefully turn the engine. Using a timing light on the number one plug wire - with the key on engine off - slowly turn the distributor until it flashes. You have now set the base timing without having to crank the engine. No flash means you have a wiring problem – find it and fix it.
Check the rest of the plug wires to make sure they are on the correct plugs in the correct firing order.
I break in street engines as they are going to be run on the street. All the vacuum lines attached, thermostat installed with 50/50 mix of coolant. If all is good you will be ready to drive the car. Delayed gratification is no fun!
Fill the fuel bowls with a little gas down the carb to prime the engine
Use a high quality oil such as Mobile 1 full synthetic 5w30 or 10w40 – this will help protect the cam during brake in. If you want to add some break in additive that is fine as well.
EDIT: There seems to be enough debate over the use of synthetic for break in that I will deffer. I never had a cam failure using Mobile one but it does delay the seating of the rings if you do not have the proper hone.
Fire the car and if it does not start right up do not let it crank and crank and crank.
Figure out the problem - spark? air? fuel? and fix it.
Start the car and set the idle to 3000 rpm and let it run there for 30 min. If it needs to be shut down then shut it down but do not let it idle. Do not let it get overly hot. Extra shop fans and even a garden sprayer to mist the radiator. Plus this will give you something to do for 30 min. Set a timer so you do not end early.
If the idle starts to rise then slow it back down to 3000 rpm. Some will drop it to 2800 for 5 min and then back to 3000 for 5 and so on – won’t hurt anything if you do this.
Things to look for:
No oiling at the rocker arms – shut it off
No pushrod rotation – shut it off
Bad noises – it will probably shut itself off. I like to have the exhaust fully hooked up if possible so I can hear bad noises and shut it off in time.
Change the oil and filter this time with a high quality non synthetic oil – this will help seat the rings. SEE ABOVE EDIT - This step is not needed if you start with a HIGH QUALITY non-synthetic oil. I personally like the 2 step break in process especially on higher lift and more rapid cam lobe ramp specs.
Run engine at 2500 for 30 min.
Set final idle and timing
Drive normally for 500 miles. City and Highway driving (no hot rodding).
Change the oil and filter with whatever oil you plan to use regularly
Swap out the carb and distributor with what you are going to actually use – don’t be surprised if you have starting issues that would have hurt your new cam.
Summary:
Lot of assembly lube
Minimal or no hand turning or starter cranking of the engine
Minimal pre oiling
Use a known carb and a known distributor
You want to hit the key and have it fire right up.
No push rod rotation is fatal.
Most importantly Have Fun!
- Paul of MO
Quick edits and follow up to other postings:
Cleveland Specific - most cam cooling comes from the splash from the crankshaft. On a Cleveland there is not much of this below 2500 rpm. Run a 351C (not a small block Chevy) at 2000 rpm and you will most likely wipe a cam lobe.
At 3000 rpm with the vacuum advance correctly connected on a known distributor the timing will be advanced and the engine will run nice and cool.
At 3000 rpm there will be significant air flow through the radiator to keep things nice and cool. Always use a fan shroud.
Turning a freshly built engine either by hand or with the starter will displace the assembly lube. It has to be done but the more you turn it the more lube gets "squished" out of the bearings.
"Drill priming" will wash out and dilute the assembly lube. This must be done but the longer you do it the more assembly lube will be lost.
Cleveland Specific - not known for "air pockets" in the cooling system. If you have the radiator full with a good radiator cap and a full overflow tank connected there should not be any issues. A standard Ford radiator cap at 13 pounds will allow the system to "Burp" sooner than a 16 pound one will. You can always - with an abundance of caution - add more 50/50 coolant mix if the level drops excessively. It it is also good to have the heater slider all the way to warm and have the blower motor on high to help keep things cool and circulating.
If a hose leaks and it is not excessive then just let it go - the goal of this process it to break in the cam - not to keep your shop clean.
If a hose blows off then karma says you deserve to lay in a puddle of nasty icky coolant. I check all hose clamps and give everything rubber a good tug before starting an engine for the first time. Karma still makes me take a coolant bath from time to time.
25 min vs 30 min - the extra five minutes is not going to hurt anything.
New oils are great for breaking in the cam but not for seating the rings. This is why I do it twice. Once with synthetic for the cam and once for with conventional for the rings.
Now I will randomly link something from the internet:
Decided to delete the link - it was mean: PM me if you want to see it! It would have been really funny to leave it up.
I have been doing this since 1956 (yep - nineteen hundred and fifty six) and had more than one engine blow up on the test stand!
Always use eye protection.
Paul of MO
Build the engine
Use generous amounts of assembly lube.
I soak the new lifters in warmed motor oil with a little assembly lube dissolved in it over night.
Do not pre pump up the lifters before you install them – it may hold a valve open during initial startup keeping the engine from starting.
Unless it has a .6 lift cam or higher there is no need to use weaker break in springs.
With the valve covers off use a drill to spin the oil pump - just long enough to see that you have good oil pressure. Once all the rocker arms show oiling STOP – you do not want to wash away or dilute the assembly lube. One great tool to make it to cut the top off a pair of old valve covers to keep the mess down but still being able to see everything.
Some turn the crank by hand one full turn while “drill priming” – I do not, once I see oil at the rocker arms on a 351C I know that everything has been oiled.
Use a known carburetor that will immediately start the engine and run the engine. I usually pull one off of a running and recently driven car to eliminate the unknown carb variable.
Install a known and working distributor and static time the engine. Static timing means carefully setting the timing mark on the damper to about 10/12 degrees with the engine off using a breaker bar to carefully turn the engine. Using a timing light on the number one plug wire - with the key on engine off - slowly turn the distributor until it flashes. You have now set the base timing without having to crank the engine. No flash means you have a wiring problem – find it and fix it.
Check the rest of the plug wires to make sure they are on the correct plugs in the correct firing order.
I break in street engines as they are going to be run on the street. All the vacuum lines attached, thermostat installed with 50/50 mix of coolant. If all is good you will be ready to drive the car. Delayed gratification is no fun!
Fill the fuel bowls with a little gas down the carb to prime the engine
Use a high quality oil such as Mobile 1 full synthetic 5w30 or 10w40 – this will help protect the cam during brake in. If you want to add some break in additive that is fine as well.
EDIT: There seems to be enough debate over the use of synthetic for break in that I will deffer. I never had a cam failure using Mobile one but it does delay the seating of the rings if you do not have the proper hone.
Fire the car and if it does not start right up do not let it crank and crank and crank.
Figure out the problem - spark? air? fuel? and fix it.
Start the car and set the idle to 3000 rpm and let it run there for 30 min. If it needs to be shut down then shut it down but do not let it idle. Do not let it get overly hot. Extra shop fans and even a garden sprayer to mist the radiator. Plus this will give you something to do for 30 min. Set a timer so you do not end early.
If the idle starts to rise then slow it back down to 3000 rpm. Some will drop it to 2800 for 5 min and then back to 3000 for 5 and so on – won’t hurt anything if you do this.
Things to look for:
No oiling at the rocker arms – shut it off
No pushrod rotation – shut it off
Bad noises – it will probably shut itself off. I like to have the exhaust fully hooked up if possible so I can hear bad noises and shut it off in time.
Change the oil and filter this time with a high quality non synthetic oil – this will help seat the rings. SEE ABOVE EDIT - This step is not needed if you start with a HIGH QUALITY non-synthetic oil. I personally like the 2 step break in process especially on higher lift and more rapid cam lobe ramp specs.
Run engine at 2500 for 30 min.
Set final idle and timing
Drive normally for 500 miles. City and Highway driving (no hot rodding).
Change the oil and filter with whatever oil you plan to use regularly
Swap out the carb and distributor with what you are going to actually use – don’t be surprised if you have starting issues that would have hurt your new cam.
Summary:
Lot of assembly lube
Minimal or no hand turning or starter cranking of the engine
Minimal pre oiling
Use a known carb and a known distributor
You want to hit the key and have it fire right up.
No push rod rotation is fatal.
Most importantly Have Fun!
- Paul of MO
Quick edits and follow up to other postings:
Cleveland Specific - most cam cooling comes from the splash from the crankshaft. On a Cleveland there is not much of this below 2500 rpm. Run a 351C (not a small block Chevy) at 2000 rpm and you will most likely wipe a cam lobe.
At 3000 rpm with the vacuum advance correctly connected on a known distributor the timing will be advanced and the engine will run nice and cool.
At 3000 rpm there will be significant air flow through the radiator to keep things nice and cool. Always use a fan shroud.
Turning a freshly built engine either by hand or with the starter will displace the assembly lube. It has to be done but the more you turn it the more lube gets "squished" out of the bearings.
"Drill priming" will wash out and dilute the assembly lube. This must be done but the longer you do it the more assembly lube will be lost.
Cleveland Specific - not known for "air pockets" in the cooling system. If you have the radiator full with a good radiator cap and a full overflow tank connected there should not be any issues. A standard Ford radiator cap at 13 pounds will allow the system to "Burp" sooner than a 16 pound one will. You can always - with an abundance of caution - add more 50/50 coolant mix if the level drops excessively. It it is also good to have the heater slider all the way to warm and have the blower motor on high to help keep things cool and circulating.
If a hose leaks and it is not excessive then just let it go - the goal of this process it to break in the cam - not to keep your shop clean.
If a hose blows off then karma says you deserve to lay in a puddle of nasty icky coolant. I check all hose clamps and give everything rubber a good tug before starting an engine for the first time. Karma still makes me take a coolant bath from time to time.
25 min vs 30 min - the extra five minutes is not going to hurt anything.
New oils are great for breaking in the cam but not for seating the rings. This is why I do it twice. Once with synthetic for the cam and once for with conventional for the rings.
Now I will randomly link something from the internet:
Decided to delete the link - it was mean: PM me if you want to see it! It would have been really funny to leave it up.
I have been doing this since 1956 (yep - nineteen hundred and fifty six) and had more than one engine blow up on the test stand!
Always use eye protection.
Paul of MO
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