Engne test stands

[tubman]

I don't want to clutter up Sanborn's thread about his great new engine, so I'll start a new one.

I have always heard that an engine should initially be run for 20 minutes at a steady 2000 RPM to properly break in the cam. Now I am hearing that doing so will cause the rings to not seat properly. I have had the same experience as Mike B on that thread (having no problems with engines initially run on my stand). Either you have the new type rings that seat almost immediately, or the old type that take 500 miles. If the new type do indeed seat that quickly, then it shouldn't matter if the initial start-up is in a car or on a stand. If using the old type, 20 minutes on a stand is a drop in the bucket compared to 500 miles. The convenience of being able to run the engine cam break in on the stand is worthwhile to me. If something does go wrong, the engine doesn't have to come out of the car with all that entails. I can see where trying to do the initial 500 miles all on the stand may not be a good idea, but I don't do that.

Can anyone document the problems with rings not seating in an engine initially run on a test stand? I'd really like to know because I'd hate to think that something I have put time and effort into and am so proud of is doing me a disservice. There was a thread on the H.A.M.B. about mounting early flatheads on an engine stand using the bellhousing rather than a side mount. There were folks on both sides, but I don't remember anyone definitively saying they had had a block break on them by mounting them that way. (No, we don't need to re-visit that particular controversy again here.)

Your thoughts?

[V8 Bob]

Originally Posted by tubman

.......Can anyone document the problems with rings not seating in an engine initially run on a test stand?

There was a thread on the H.A.M.B. about mounting early flatheads on an engine stand using the bellhousing rather than a side mount. There were folks on both sides, but I don't remember anyone definitively saying they had had a block break on them by mounting them that way.
Your thoughts?

Engine stand running: My MCF flathead was run periodically on my stand for over 7 years with NO problems. I always brought it up to temp, varied the rpm and usually ran it for a minimum of 20 minutes. Engine now has about 14,000 miles. Was I lucky? Don't think so, as many of Mark's engines were demoed for many hours on stands with no problems. Molly rings probably one reason.

Engine mounting: There have been several reports of early engines that fell off stands because of integral bell housing failure, and some included pictures. Does it happen? Yes. Can it happen? Yes. Does it happen all the time? No.

[JSeery]

Originally Posted by tubman

I don't want to clutter up Sanborn's thread about his great new engine, so I'll start a new one.

I have always heard that an engine should initially be run for 20 minutes at a steady 2000 RPM to properly break in the cam. Now I am hearing that doing so will cause the rings to not seat properly. I have had the same experience as Mike B on that thread (having no problems with engines initially run on my stand). Either you have the new type rings that seat almost immediately, or the old type that take 500 miles. If the new type do indeed seat that quickly, then it shouldn't matter if the initial start-up is in a car or on a stand. If using the old type, 20 minutes on a stand is a drop in the bucket compared to 500 miles. The convenience of being able to run the engine cam break in on the stand is worthwhile to me. If something does go wrong, the engine doesn't have to come out of the car with all that entails. I can see where trying to do the initial 500 miles all on the stand may not be a good idea, but I don't do that.

Can anyone document the problems with rings not seating in an engine initially run on a test stand? I'd really like to know because I'd hate to think that something I have put time and effort into and am so proud of is doing me a disservice. There was a thread on the H.A.M.B. about mounting early flatheads on an engine stand using the bellhousing rather than a side mount. There were folks on both sides, but I don't remember anyone definitively saying they had had a block break on them by mounting them that way. (No, we don't need to re-visit that particular controversy again here.)

Your thoughts?

I break in cams with the engine statuary in the car or on a stand, only difference would be varying the rpm and not running it at a constant speed.
My current block was broke on an engine stand (not by me). The issue is with the 59a or earlier, not the later blocks.

[Ol' Ron]

I don't think running an engine on a stand for 20-30 minutes will do any harm, and probably some good in breaking in the cam and lifters. However, very nice run stands have a habbit of keeping the engine running for th benefit of friends to listen to the old flathead run. Jazzing the throttle washing the cylinder wals with gasoline, etc. Now does running an engine stand ruin the rings? I can't answer that with a definitive answer yes or no, but why take the chance, You have allot invested her, take it for a ride.

[flatjack9]

Every engine I have ever built has been run on one of my test stands. I do run it to around 2000 rpm, but not for 20 minutes at the same speed. I let the temperature get up to operating levels to check the thermostat operation. No one has ever come back and said that their rings did not seat.

[rotorwrench]

Sponsored Links (Register now to hide all advertisements)

The only benefit I can see to using a test stand is to make sure the old iron is going to hold water. It is much easier to remove an engine from a test stand than it is from a vehicle if it leaks all over the place. As far as bedding the bearings in, it is of no consequence to run it on the stand for a while. As far as a good break in of the cylinders, it's worthless. You have to pull power to break in the ring to cylinder interface. There is no other way to gain the in service cylinder pressures on a test stand unless you have it connected to a water brake where you can pull some horsepower.

[tubman]

Originally Posted by Ol' Ron

I don't think running an engine on a stand for 20-30 minutes will do any harm, and probably some good in breaking in the cam and lifters. However, very nice run stands have a habbit of keeping the engine running for th benefit of friends to listen to the old flathead run. Jazzing the throttle washing the cylinder wals with gasoline, etc. Now does running an engine stand ruin the rings? I can't answer that with a definitive answer yes or no, but why take the chance, You have allot invested her, take it for a ride.

Thanks Ron, since it was your post that got me thinking about this. You don't have to worry about me "benefiting my friends". I have an early short bell hemi in it now (which runs great). I have an Olds rocket that needs to go on it next (it looks freshly built with an Isky cam and Gotha rockers), and then a '51 Merc (that I have already heard run), and then a couple of more flatheads that I am going to do. (I don't think I'll live long enough to get all of this done, but I'll try like hell!)

[Ronnie]

Originally Posted by rotorwrench

The only benefit I can see to using a test stand is to make sure the old iron is going to hold water. It is much easier to remove an engine from a test stand than it is from a vehicle if it leaks all over the place. As far as bedding the bearings in, it is of no consequence to run it on the stand for a while. As far as a good break in of the cylinders, it's worthless. You have to pull power to break in the ring to cylinder interface. There is no other way to gain the in service cylinder pressures on a test stand unless you have it connected to a water brake where you can pull some horsepower.

Common sense prevails again. +++

R

[1939 pickup truck]

Howdy Gents,
Perhaps as a counterpoint, in aviation circles, one takes a freshly done over hauled motor installed in an aircraft, and once one knows there are no oil leaks, the phrase "Fly it as if you hate It... " full throttle for at least 1 hour. This fully seats the rings into the freshly honed cylinders most reliably. I suspect a warming up, check all, then hot and hard is the goal.
Tigger

[tubman]

So far, lots of opinions, but no instances of problems. Anybody got any "horror stories"?

[Brendan]

I have always started my fresh motors in the vehicles that it go in, I don't have room for a test stand. start, run at about 1000 rpm for about 20 min, check vitals, then drop the oil and filter. fill it with fresh oil and fresh filter then hit the road !

[Mike B]

Originally Posted by tubman

So far, lots of opinions, but no instances of problems. Anybody got any "horror stories"?

I think as Ron has alluded to, some may put it on a stand for a few years while they are prepping the car/ruck for the engine...over the course of time...it's fired up x amount of times, to just hear it run, showing it to friends, ec...

Me...I've never done that with any engine...now to be honest I've only assembled a few big For engines, several SBC's and two LA Dodge engines, but always ran them on the stand...even the roller motor SBC's, not just for water leaks, but for oil leaks, abnormal noise, etc...and ofcourse to break in the flat tappet cam's I have used.

It's just easier to see an issue, or find out about one and fix it, before installing it in the engine...

Now, that said, guys who build many engines, and know for sure that 99.99 percent of the time, all will be okay...know they can put it in the car/truck...and roll...those of us who just do it once every few years (like me)..have to have the "feel good" feeling before we install them in our vehicles.

[1939 pickup truck]

Howdy Fellows,
With a now torn down 41 A11 on a cart, but needing an engine stand, any suggestions to design detail given the only half flywheel housing set up.
Tigger

[jake197000]

i dont own a run in stand doing this 41 years.have i had a couplr that burned oil yes.my fault.but i think cylinder wall finish and proper clearances are the key.its not as fussy as some say.if its built right put it in ,warm it up 20 min. and go drive it.proper cyl wall finish matched with ring type is key in my opinion

[Ronnie]

Originally Posted by jake197000

i dont own a run in stand doing this 41 years.have i had a couplr that burned oil yes.my fault.but i think cylinder wall finish and proper clearances are the key.its not as fussy as some say.if its built right put it in ,warm it up 20 min. and go drive it.proper cyl wall finish matched with ring type is key in my opinion

Very solid opinion good observations.

R

[JWL]

Yes, I have seen examples of ring "seating" problems which were attributed to running without load. Yes, I have seen ring "seating" problems where the load was almost immediately imposed. There are several factors involved with one of the more important being how accurately the dynamic ring circumference matches the cylinder bore. Maintaining "round" bores and surface finish texture characteristics appropriate for the selected components are important. Moly rings are almost "broken in" by the time several revolutions of the crank are completed while setting the valve clearances. However, most Flathead builds do not involve moly rings.

If there is a choice always put the engine under load, to apply full pressure behind the compression rings, as soon as practical with your new build. Also, avoid periods of low RPM operation.

[stangblue]

Horror Story Yep! Bought an engine a Stroked Long Block Racing Ford Engine from the Left Coast shipped to the Right Coast. Put it in the car, the rear seal leaked, the oil pan leaked. When starting and driving the car noticed a bad vibration in the floor of the car. Called the engine builder said my flywheel and clutch assembly was out of balance, it is a 28oz. off balance. Dropped the Drivetrain and had it matched balanced the assembly at a machine shop checked out OK. Put the Drivetrain back in the same thing?? Then I pulled the harmonic balancer they plowed the damper on and buried the keyway in the crank!!!! After I called back and complained they hung up on me and wouldn't take my calls. Well, I met the people unexpectedly at The Sema Show in LV. That's another story. I would have liked to put it on an engine stand and starting it before installing it. Lesson learned! While Drag Racing the same engine it spun a bearing. Engine out again, had the rotating assembly balanced and had the crank nitrated runs like a Swiss watch with a little thump that's the right kind of thump I mean. lol

[rotorwrench]

On aircraft engines, it isn't considered completely overhauled till it is tested. They can be run with a test club that will simulate a load but some engines aren't designed for a propeller so they have to run on a test stand with a water brake to simulate real power conditions. If it's not tested, it can't be approved for return to service. Most operators test them in the airframe but you have to check the calibration of all the engine related instruments in order to do that. It then has to be run about 30-minutes for bedding in at stair steps of rpm settings then flown at 75% power for 30 minutes. The manufacturere's state to run them at 100% for an hour after that but that's not practical at all for most aircraft. Pull a lot of power yes but 100% may cause more problems than it's worth. We just load them heavy and fly fast and that's good enough in my book. Change the oil & filter then put it back into normal service. A good cross country after that will do the rest. Watch the oil consumption to make sure it tapers off to a normal usage.

[Kahuna]

Rotorwrench is absolutely correct re: the need for a load.
The most current engine I assembled was never started until it was on the dyno.
Before it was started, the operator removed the oil fill cap.
As soon as the engine started, you could watch as the blow-by exited the oil fill
pipe. There was a LOT of blow-by.
However, after 3 or 4 "pulls", all visible blow-by was gone.
Rings are seated. Engine runs great

[1939 pickup truck]

A respectful tip of the hat to rotorwrench for his aircraft engine knowledge here.
I recently completed a Continental C-85-8-F ( Flat Four from the mid 1940's )
once it was known to not be dripping, I flew it hard for 2 hours, all over the local
airstrip just in case something let go unexpectedly, no coasting to the curb up there.
Minimum of 8-10 hours with break in old, and check everything after an oil & filter.
Now my little 1946 J3 Cub climbs like the proverbial "Home sick angle" at 750 VFPM
Tigger