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Engine Specific Info and Questions => IDI Engine => Topic started by: Rabbit79 on March 17, 2011, 12:29:46 pm

Title: Break in and head bolts
Post by: Rabbit79 on March 17, 2011, 12:29:46 pm
Well the old Rabbit will be ready for its first start up in a day or two, and I've been mulling over a few things about breaking it in and the final torque on the head bolts. In reading the threads about breaking in, the prevailing opinion seems to be to put the motor to work right away and not let it idle too much. So..... my current plan is to get it started, then jockey the throttle back and forth to keep the RPMs varied until I get it up to operating temparature, then shut it down to do the final torque on the head bolts, and then go about a full break in procedure. Is this the correct way to go about it, or am I off base? Any suggestions appreciated.
Title: Re: Break in and head bolts
Post by: maxfax on March 17, 2011, 09:20:22 pm
Usually to get these things up to operating temp you have to rev them up a bit anyhow..   Sounds like you are right on track...
Title: Re: Break in and head bolts
Post by: DCC on March 18, 2011, 01:47:36 pm
Well the old Rabbit will be ready for its first start up in a day or two, and I've been mulling over a few things about breaking it in and the final torque on the head bolts. In reading the threads about breaking in, the prevailing opinion seems to be to put the motor to work right away and not let it idle too much. So..... my current plan is to get it started, then jockey the throttle back and forth to keep the RPMs varied until I get it up to operating temparature, then shut it down to do the final torque on the head bolts, and then go about a full break in procedure. Is this the correct way to go about it, or am I off base? Any suggestions appreciated.

A couple months ago I finished a rebuild of a friend's mk2 and what we did was:

- Start it. Drive around very, very gently, until working temperature.
- Re-torque
- Break in

However, you're quite right on not letting it idle too much. On stops and red lights, change a bit the rpms with small accelerator taps.
Title: Re: Break in and head bolts
Post by: dankcorey22 on October 06, 2011, 08:31:12 pm
Sorry for bringing this topic back from the dead, but i have a question. What did you retorque the head bolts too after getting the engine to operating temp. the first time?
Title: Re: Break in and head bolts
Post by: R.O.R-2.0 on October 07, 2011, 09:50:39 am
Sorry for bringing this topic back from the dead, but i have a question. What did you retorque the head bolts too after getting the engine to operating temp. the first time?

im guessing the final 90* turn on the stretch bolts..
Title: Re: Break in and head bolts
Post by: DCC on October 07, 2011, 12:28:46 pm
Sorry for bringing this topic back from the dead, but i have a question. What did you retorque the head bolts too after getting the engine to operating temp. the first time?

im guessing the final 90* turn on the stretch bolts..

Exactly.  :)
Title: Re: Break in and head bolts
Post by: vdubspeed on October 07, 2011, 01:21:49 pm
I'm about to finish a motor and I wanna make sure I get this correct too.

Bentley list the initial torque. Then you hit it with 1 90degree turn. let it warm up and then turn it 90 again. Do you do the second 90 when the motor is warm or cold?

Sound about right?

Thanks.
Title: Re: Break in and head bolts
Post by: mtrans on October 07, 2011, 01:26:49 pm
This gay have another story?http://www.mototuneusa.com/break_in_secrets.htm (http://www.mototuneusa.com/break_in_secrets.htm)
Title: Re: Break in and head bolts
Post by: Rabbit79 on November 19, 2011, 12:36:32 pm
Sorry I didn't answer this right away but I haven't been on board for awhile. After I got the motor up to temp I did a quarter turn (90 degrees) on the bolts. I did it right away, engine still warm, the only time interval was how long it took to get the valve cover off. This is with the 12-point allen type head bolts, just so you know.