Jump to content
SAU Community

Recommended Posts

Hi Folks, and especially those in the know.

Dumb question time

About to have yet another freshly rebuilt engine to do a run in on.

However, before it felt the need to be rebuilt, it was an 8.2:1 CR running E85 (but has flex capability)

It will now be 9.01:1.

My questions are:

1) Conventional wisdom (google) says that washing bores down is usually due to too much fuel and rah rah rah. Given E85 is using 30% more fuel pretty much all the time, would be swapping back to 98 pretty much vital or does E85 do magic to ensure this is a non issue?

2) With the CR increase, would I need to be dropping timing in the area that is OFF boost. If so, how much? Can I just drop a blanket -X degrees and "she'll be right mate" or is this epically stupid?

I've been advised that the way to do the run in (by the guys building engine) is 500 or so kms of easy, off boost, varied driving but not too much load (i.e, pretty much off boost) just to get it all rotating.

Then dump oil, and 500kms or so on 'some' load. In this case, sort of half throttle, 3-5 psi, up hills, a little bit but no crazy WOT 30PSI "load"

Then drop the oil again and tune. They however weren't really sure on 1) and 2) above.

Thoughts?

Surely someone has had to run in an engine which has more comp ratio after a rebuild and thought "hhmmmm..."

Link to comment
https://www.sau.com.au/forums/topic/454265-engine-run-inbreak-in-query/
Share on other sites

I have read that in the past...

Fuel won't be an issue as the car has a (correctly working) wideband. Timing obviously need a dyno.

I'll obviously at least check things on the dyno. I don't know how much difference 8.2 to 9.0 CR will result in.

Does anyone?

That link almost insinuates first turn of the key is on a Dyno then immediately do a 400RWKW power pull.

But I've also read people build engines and then "run them in" on the way to the drag strip in the morning and then go do passes at 175mph.

I'm just looking for some info. The tuner may very well say "Hmmm, I'm not sure either?" therefore I was curious if anyone had done it and their results of doing so.. if available.

The 4 door's back on the road Greg? Nice.

Definitely need some boost to bed the rings imo, but any good tuner will have done this many times and have their own ideas on it surely. Remember, you only get one good shot at fileing those rings to match the bore.

Don't be surprised if the engine spews oil from every seal in the process, my Evo engine was leaking everywhere before the rings bed, as the blowby was crazy. Seen that a few times too.

You need light boost for bed in.

When the bores are new, the hone leaves a finish thats rough and creates a lot of initial wear AND heat.

So start with lower RPM, low boost, load up the engine with Accel, keep RPM's lowish, progressivly increasing load and RPM as the peaks of the hone get worn off.

And as importantly to accel and give it some power, decel is just as important as it pulls the crap off the bores.

So dont pussy foot it, but dont start off with crazy load and RPM, progressivily increase the load and RPM.

Also you need your mixtures to be right, regardless of if its E85 or 98, too lean, too much heat in a cylinder thats already getting hot from bedding in, too rich washes off the oil thats lubing your rings which are going through a hard time and need oil to cool them during the high friction phase.

The real problem with the need to bed rings on load when confronted with an untuned engine is not having the time available to get the fuelling and timing right to allow you to run it on load. If your engine is at least basically the same as before, sans the compression boost, then it is likely that your fuel map will be perfectly fine for enough load to bed it and run it in a bit. The timing is another matter. I would pull a few degrees out pretty much everywhere. You can't really hurt it by doing so - it will just make less power and you don't care about that. It would be most important to soften the timing in the boost transition area where it may well have been quite aggressive if your previous tuner was trying to get you the best response possible.

As to the question of E85 washing the walls.....just because it uses ~30% more doesn't make it more likely to wash the walls. If the mixtures are right then the fuel will burn, provided it's actually firing!

I won't be too worried about the fuel, it has a wideband controller and a gauge and I'm familiar enough with the Haltech that I can change fuel maps on the fly to get it happy.

Main problem was as GTSboy has mentioned, the time it takes to get the timing right.... is critical time to make sure the engine is being run in at all.

It's on E85, so pinging was never a problem. I don't know how 'much' timing to pull to accompany 8.2 to 9 CR. I can easily just pull -X degrees everywhere and then go for a drive, my main concern was pulling too much, could affect how the run in is actually done. Can confirm I don't care about power during the run in.

The 'problem' is the previous engine kind of made 350RWKW at 4000rpm. If you're trying to "Load it up" in a high gear at medium RPM then there's a good chance that uh, it's kind of party time in those cells..... with a different CR. The characteristics of the engine meant 5-10 psi happened quite a lot while just cruising around at 30-50% throttle at 2-3k rpm. You could argue that that's pretty ideal for running an engine in.

If E85 isn't a big deal, or doesn't cause any crazy problems for bedding an engine in, then that's a great piece of news for me, because it may only need 'minimal' adjustment to account for the extra CR, which isn't that much, I'm not going from 8.2 to 13.5 or anything of that nature.

Just pull a few degrees. It won't stop you from being able to run it with enough load to bed the rings. It also won't likely ping, as you say, even if you should have pulled more, because E85.

Set the boost as low as you can and set the boost controller to not keep the wastegate closed agressively.

Very First start always run at a constant ~2500 for about 15 minutes as to get the oil "everywhere" so to speak.

Dump the oil, put new in.

Just drive it normally for around like you say 500km, normally meaning every day driving.

Essentially the break in process is to prove that no tolerances are incorrect

in theory a proper engine rebuild should need 0 break in time and should be able to be run 100% after first start after 2500 idle process.

But nothing is perfect in this world.

That said, im not sure about the e85 affecting this process, and im not sure there is enough evidence out in the world to convince anyone aswell.

Edited by jay-rod

Very First start always run at a constant ~2500 for about 15 minutes as to get the oil "everywhere" so to speak.

I think you'll find a very large number of people will tell you that running an engine at a constant speed is going to cause worse ring bed in than almost any other option (except idling it).

  • Like 1

I think you'll find a very large number of people will tell you that running an engine at a constant speed is going to cause worse ring bed in than almost any other option (except idling it).

Interesting, i mean ~2500 with no load by the way, not moving.

If you were to have a to rich fuel map, that would cause wash in on the cylinder walls correct?

And that would be easy mistake to do with 85 ?

Edited by jay-rod

That would be very bad.

You need lots of cylinder pressure acting on the rings to make them shape up to the bore wall and knock all the high spots off. If you don't (ie idle it or hold it at a constant speed, or even just drive it around really gently) then the rings will glaze up and you'll not get a good seal. Then you start chucking Bon-Ami down the carb (if you're living in the 70s).

Well i will throw that out of my head then, not sure why i thought otherwise.

I assumed the short period was not long enough to cause that on the rings.

More so for a fresh engine with "dry" internals to get the break in oil to get to those locations it wouldn't normally be on a first topup.

Sad. But ultimately doesn't matter. You could beg a mod to delete the whole conversation. In the long run though you learned something that may save an engine that you're starting up for the first time, and the conversation might be more convincing (to some future reader) presented as it is rather than just a blanket statement saying "Do X because you have to".

Just claim your kid brother or idiot mate used your login.

Happy to help....

And I'll just add for reference, when cranking engine to build oil pressure remove plugs to remove load from bearings and pull fuel pump fuse.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...