Tips on breaking in a rebuid?

[6cylinderstepside]

I am picking up my rebuilt engine tomorrow morning. Just a regular rebuild long block with no frills. Same pistons and cam, but new liters springs, etc. since it has the original cam I assume I don't need to break in the cam but I will need to set the rings. So once I have it all put back together and on the run stand any tips? I have heard run it at 2k RPM for two min but that's from my feeble memory. I've swapped tons of engine and stabbed tons of distributors so TDC and timing is not an issue but I've never had an actual rebuilt motor that I had to break in...

It's an inline 6 250 by the way.

[sawman]

first make sure all fluids are full lol, always just start it up and let it run around 1000 rpm till thermostat opens,then I shut it down check all fluids again.look for leaks/drips ect,then I fire it up run about 1500 rpm every now and then taking it up to 2000 rpm,for 30 min,shut it down check fluids again,take it for a ride if its ready and run it around 2000 rpm ,do not bog it down,or over rev,drive it around for awhile,i always change oil and filter right then,should be fine,seems to work good that way,

[turbosix]

I"ve never broke one in on a stand. If the cam is broke in there is no need to break it in on the stand but if you do the previous advice is great. The method I use in the truck is I get it up to temp then put my foot in it. Never had a problem and shouldn't if it's built right.

[geezer#99]

[QUOTE= since it has the original cam I assume I don't need to break in the cam

It's an inline 6 250 by the way.[/QUOTE]

You would be assuming wrong!
You'll need to break it in like normal. 2000 rpm for 20 minutes.
No idling or shutting down to check for leaks.
Reason is the new lifters and old cam. They need to wear in togethor.
There is a good possibility your cam will go flat anyway.
Likely better to tear it down and put a new cam in first.

[77 Big 10]

After you have broke in the cam/valve train & bearings, you'll need to break in the rings. They need to be under a load. If an automatic, we'd run it up an incline, in high gear with the kick down disconnected, slow down and then throttle it putting it under a load. We'd continue this multiple times to break in the rings.

[UKNOWME]

Why didn't you replace the cam? All that work and such a crucial piece. I've always believed cam and lifters go hand and hand.

[Zach079xxx]

I'm in the same boat, getting my 350 built Monday. Keeping everything the same but a new cam and timing chain kit, intake, and carb. What's my process of breaking it in instantly then long term? 500 miles then an oil change I heard?

[6cylinderstepside]

I'm no pro on engine rebuilding and never claimed to be, this is my first rebuild and I paid to have it done so I am not going to be tearing it down to replace the cam. I went to the most well known and respected engine rebuilder in Dallas, City Motor Supply. I ordered the premium long block and put my faith in their strong reputation. The cam is inspected, reground and replaced IF NEEDED. I don't think City Motor Supply has been in business since 1943 with the reputation they have from anyone I have ever talked to if they didn't know how to build engines, or had a shady business policy. I do agree replacing everything is always a great idea but if it is not warranted.

After the comment about the cam going flat, I did some research and yes multiple sites said that using old lifters with a new cam will do that will flatten the lobes, but not one site said any issue about an old cam with new lifters so you might be thinking of it backwards.

Since I also just got three completely different ways to break in the engine, I think I'll just keep doing my research on my own, thanks anyways.

[6cylinderstepside]

Originally Posted by Zach079xxx

I'm in the same boat, getting my 350 built Monday. Keeping everything the same but a new cam and timing chain kit, intake, and carb. What's my process of breaking it in instantly then long term? 500 miles then an oil change I heard?

Zach, read above and make your choice from the many opinions. I'm out.

[UKNOWME]

Originally Posted by 6cylinderstepside

The cam is inspected, reground and replaced IF NEEDED.

If they reground the cam, that makes sense. Forgot about that option.

Did you ask your engine rebuilder what they suggest? Most of the builders in my area break them in on the stand before returning them to the customer.

[Zach079xxx]

Thanks, that was my plan. Just seeing what everyone voices on how to do it.

Originally Posted by 6cylinderstepside

Zach, read above and make your choice from the many opinions. I'm out.

[77 Big 10]

Originally Posted by Zach079xxx

I'm in the same boat, getting my 350 built Monday. Keeping everything the same but a new cam and timing chain kit, intake, and carb. What's my process of breaking it in instantly then long term? 500 miles then an oil change I heard?

When you do the break in on the bearings, cam & valve train, there is going to be a lot of metal in the oil. Before I break in the rings I change the oil & filter.

[geezer#99]

Originally Posted by 6cylinderstepside

I'm no pro on engine rebuilding and never claimed to be, this is my first rebuild and I paid to have it done so I am not going to be tearing it down to replace the cam. I went to the most well known and respected engine rebuilder in Dallas, City Motor Supply. I ordered the premium long block and put my faith in their strong reputation. The cam is inspected, reground and replaced IF NEEDED. I don't think City Motor Supply has been in business since 1943 with the reputation they have from anyone I have ever talked to if they didn't know how to build engines, or had a shady business policy. I do agree replacing everything is always a great idea but if it is not warranted.

After the comment about the cam going flat, I did some research and yes multiple sites said that using old lifters with a new cam will do that will flatten the lobes, but not one site said any issue about an old cam with new lifters so you might be thinking of it backwards.

Since I also just got three completely different ways to break in the engine, I think I'll just keep doing my research on my own, thanks anyways.

That's what you get for leaving info out of your thread.
A long discussion unrelated to your actual situation.
If we'd known it was reground, nothing would have been said.
Apoligies for the mis-direction.