Rebuilt engine break in question

[eclipsek17]

Had a quick question, I know there is a million engine break in posts but, I have been reading throughthem and have not found an answer to what I am looking for. I just rebuilt engine from block up, new bearings, rings, etc and I put non synthetic 10-30 in my car and let it idle at 2000k rpm for about 10 min, then I took it out and did a 5 5500rpm pulls and let engine bring itself down. I am wondering three things though. One, is it ok that I used 10-30? I read another post that said to used 10-40. Two, how many pulls should I do for the rings to set? Should I just pay close attention to vacuum gauge until it starts reading normal? Three, is it bad to boost between 14 to 18lbs while doing the 5500rpm pulls? I am trying not to get into boost too much but it climbs way to fast.

 

[eclipsek17]

Also is it bad if I wasn't able to keep it at a steady 2000 rpm while idling at first start up? I had a disconnected vacuum that I was unaware of and the idle was fluctuating between 2000 and 3000.

 

[fastfred]

I used 5w30. My motors fine, yours likely is too. The main thing is to change the oil frequently and drive it like your gonna drive it all the time, dont go "easy" on it. Id change it now then 100, 250, 750 or something along those lines with conventional oil. Then switch to an interval and oil of your choice. I use brad penn 15w40 every 2k. Rings seat fast i know some guys that dont do the elevated idle at all with roller cams. As soon as its at temp no leaks they go drive it.

 

[eclipsek17]

Thanks for the advise. Just nervous. I plastigauged and gaped everything to exact specifications from all data, but I am just still nervous and hope everything is broken in properly.

 

[fastfred]

I forgot to mention, i used break in oil the first time and a zinc additive the second time lucas i think. A lot of people dont though.

 

[SrKegler]

You broke it in the same way I do. You're just nervous and worrying if you got everything right.

I do the first oil change right after the initial break in. Just want to get all the crap out of the engine. 2d change is at 250 mile. I then go to regular intervals.

If there's no noises or oil leaks, set back and enjoy your labors.

 

[eclipsek17]

Everything sounds perfect, no noises at all. No leaks, except one I am trying to figure out with my transfer case. But I did a compression test just to see where I was at and it didn't seem to good, unless compression gets better as rings set. I have from cylinder 1 to 4, 150, 140, 155, and 170 on a dry test. Is this normal for a refresh rebuild? I have only put 10 miles on it and did the first oil change at 8 miles.

 

[JacksonAuto]

t. I have from cylinder 1 to 4, 150, 140, 155, and 170 on a dry test. Is this normal for a refresh rebuild?

What kind of pistons?
What kind of ring gaps?
Did you rebuild the cylinder head?
How did you hone the cylinders?

A 30psi variance between cylinders isn't too good.

 

[eclipsek17]

7 bolt pistons, with new Mitsubishi rings, I didnt gap them, is that where I messed up? The head was resurfaced, new cams, new lifters, but that was it. I was on a very tight budget and had to get my car running again. I had the block surfaced and honed at the machine shop. Vacuum on cold start reads 15 steady, once it warms up it reads 18 steady.

 

[JacksonAuto]

Well the next step should be a leakdown test to determine where the compression is going. Could be the rings or valve seats. Stock rings typically don't need to be gapped but it's a good idea to check them before installation.

 

[eclipsek17]

How do I do a leakdown test? I am not familiar with that. I did a wet compression test and compression was good across all cylinders, only like a 20 psi difference from 190 to 210 psi.

 

[eclipsek17]

I cant afford to open this engine back up right now though. I spent everything I had just to get it working again so I could have transportation to find a new job. I haven't been paid in a month at the shop I am work in at now.

 

[YZFR1]

^I think you should be fine, especially for a budget build. Have heard some people running with only 90 psi compression in one cylinder and engine still make power.

 

[boost97gst]

^I think you should be fine, especially for a budget build. Have heard some people running with only 90 psi compression in one cylinder and engine still make power.

Yup, that'd be me.. 185 across all 3 and 1 with 90psi. Took me a while to even notice it. You couldnt tell until airflow was in the high 40s then certain things weren't clickin like they should have been. Other than that she drove and idled really really well. Still surprised by it....

 

[eclipsek17]

Cool, well hopefully I am good until I get some money to drop in this again