Topic: new engine break in period and quick intake question AEM

[stan98tj]

im about to put in my new 2.5l in my 98tj, anyone know what or if there is a break-in period on new/remanned engines?
also, im planning on putting in an AEM brute force intake, ive read what i could in previous posts the only question i have left is what's the chance of this messing with any sensors or messing with the engine in any way. Has anyone heard of these things messing up, if so can i do anything to prevent future problems
thanks

[jcsanders79]

When I had mine rebuilt the only thing I was told to do is change the oil after 1000 miles.  I don't believe in breakin periods anyways.  Every time I have bought any thing that has one (it is usually motorcyles or ATV's, don't hear much about cars needing a breakin)  I have given it hell right of the bat and never had an issue, infact I feel like it helps performance in the long run you evenly wear the cylinder in at all rpms.  This is especially true for crotch rockets, I never bought one that I didn't leave the dealership on the rear wheel and never had a problem.

[stan98tj]

thanks for the advice! just wanted to make sure not to break anything!

[chardrc]

ive heard both ways... on our 2003 duramax diesel they said the warranty voids if you don't break it in. but then i heard from an engine builder and other people that you need to work it hard right away and then let it sit for 24 hours to cur or something.

[Clip]

You probably shouldn't run synthetic oil in it for the first 1000 miles.

[jcsanders79]

You probably shouldn't run synthetic oil in it for the first 1000 miles.

Yeah he told me that too, forgot that part.  I have used synthetic ever since though.

[gomi]

As for the AEM, the only thing that seems to be an issue is that intakes will often leave a layer of fine dust particles that pass the filter. Eventually all that gets into your jeep. Shouldn't mess with sensors or anything though.

[Jeffy]

As for the AEM, the only thing that seems to be an issue is that intakes will often leave a layer of fine dust particles that pass the filter. Eventually all that gets into your jeep. Shouldn't mess with sensors or anything though.

That actually goes for most of not all of the rechargeable filters.  Many of my Socal friends have switched back to paper because of this.  They're always rolling around in the desert so it's more noticeable.

[stan98tj]

thanks for all the posts! wonder what the problem would be with synthetic oil? so we're talkin break it in for about 500-1k miles. and by break it in we mean no hard acceleration, no speeds past 65, and no long distances? im asking only because the company who sold me the engine hasnt provided me any info on these matters.

[Mr_Random]

From what I've read, synthetic can do a number on metals and gaskets that haven't already absorbed all the dino oil they can get. They have such fine and precise molecules (because they're man-made) that instead of saturating rubbers and metals, they break them apart, unlike Dino, which is random, large, and more easily absorbed (but not as efficient as far as lubrication goes, due obviously to the fact that it absorbs and gets burned away more easily).

[Jeffy]

thanks for all the posts! wonder what the problem would be with synthetic oil? so we're talkin break it in for about 500-1k miles. and by break it in we mean no hard acceleration, no speeds past 65, and no long distances? im asking only because the company who sold me the engine hasnt provided me any info on these matters.

The problem is wear.  When you rebuild or have a new engine, you need some wear so the parts seat/match up to each other.  Synthetic's work against this.  Those engine that come with synthetic engines are usually built to higher specs and are more performance oriented engines.

This wear is why your gas millage typically goes up after the engine has been broken in.

This is also true for gears.  Gears are mated/matched and run on a machine that basically shot peening them.  When you install gears what you're trying to do is match the setup from the factory and finish the shot peen process.

[stan98tj]

thanks for all the info. had the engine almost in, ran into a snag when i took the timing cover and realized the timing chain guide had snapped..its off to the local shop to pick one up. not much more to go now.