ok, if all goes as planned (and it NEVER does) I'll be starting up my rebuilt motor this saturday... I've got questions...

ok, I've also got a new transmission, and lots of pressure checks have to be done during the first transmission start-up, so I plan on disconnecting the torque converter from the flywheel and pushing it back on the transmission until I run the engine for a while...

So my problem is.... how should I go about breaking it in. I heard something about right after I start it I should hold the RPM at approx 2000-2500, in order to breaking the new cam. is this correct, and if so, should I fire it up then go right up to 2 grand with out much idle...????

Then if I need to do that, what should I do after that? how long should I run it before shutting it off? should I give it 'resting' periods? should I rev it all the way up at all? should I run it for 1 hour, 2 hours... until I hook up the transmission and drive it?

Sorry so long, but as you can see I'm clueless on how to do it RIGHT... How do you all go about it???? time incriments on start-ups and shut offs, and off and on??? rpm range???? all that stuff?

:confused: :confused: :confused: :confused: :confused: :confused:

Thanks ALOT!

 

It's a roller cam and needs no break in times. Just start it check all you fluids for leaks and oil pressure. I'd let it run up to normal temps then dump the oil and filter.

 

What did you do in the rebuild?

What's the logic in disconnecting the tranny? Not that there's anything wrong with that, I've just never done it or thought about it. (Granted, it's been a looong time since my last rebuild!).

 

It is true that a roller does not need the break-in, but it is still a very good idea to follow the same procedure just to get all the assembly lube circulated out of the engine (you will also have some metal shavings as well, that is normal). Run it for ~20 minutes varying rpm between 2k and 3k. This slings the oil into diferent places than if you hold a constant rpm the entire time. Change the oil, and run it for another 250 miles with that oil. Change it again and run it for 1500-2K miles and change it once again and you can incorporate a regular schedule after that and you can switch to a full synthetic at that time as well.

The initial oil should be a straight 30 or 40 weight. The other should probably be a 10w-30 regular oil (no synthetics). I use Valvoline for the 10w-30 and the cheap generic brand of straight 30 weight for the first 20 minutes.

 

Most important thing to do is prime the engine oil pump prior to installing the intake. The bearings in LT-1's are particularly sensitive to oil starvation.

I learned this lesson the hard way. Changed the cam in my Dad's car, neglected to pre-lube the motor and wound up with spun rod bearings. It's never been issue when I've changed the cam on my Ford 302s but the LT4 wasn't too happy about it.

 

When I installed the roller cam in my Firebird I did not use pre-lube on the cam lobes. Only on the bearing journals. The reason is that with a roller lifter the pre-lube could cause the roller to slide across the cam lobe intead of rolling. This could damage the roller. So I've just soaked the cam lobes with oil. With flat tappets pre-lube is needed since they do slide across the cam lobe.
The reason for holding the rpm at 2000 or so on initial startup is that the cam lobes are lubricated by the oil flung up by the crank shaft rotation. So you want the crank turing faster than just idle speed to ensure that you get plenty of oil on those new lobes.
Have fun. :)

 

Quote: "What did you do in the rebuild?"

Well, I pretty much replaced everything except the pistons and rods... I was able to use the standard pistons and even standard size rings. The crank was turned 10 on the mains and 10 on the rods. new lifters, cam, bearings, oil pump, timing chain set, opti, waterpump, and transmission.


Quote: "What's the logic in disconnecting the tranny? Not that there's anything wrong with that, I've just never done it or thought about it. (Granted, it's been a looong time since my last rebuild!)."

The transmission has a series of pressure tests I have to do the FIRST time I run the transmission... this means the first time the tranny is hooked up to the flywheel and the engine is started... so in order to give the engine a litttle break-in before I do all the transmission pressure tests, the transmission company recommended I unbolt the torque converter and push it back on the tranny... It just saves me the trouble of doing a million things at once at the first turn of the key!!!


At any rate, I think I'll go ahead and do the 20 minute break-in... then kill it, then start it back in a few minutes, and then run it through a light variety of loads for about 10 minutes... then change the filter, and do the transmission tests, then change the oil and drive it for a couple hundred miles......whooooo! that was a breathful! Still looking like saturday morning.... I sure hope it starts!! I'll post up an update when it all happens, and explain the problems if any for any of you considering a complete rebuild...

Thanks for all the input... every bit helps