Breaking in new Cam and Rockers in an M20

[Earendil]

I'm having a hard time finding info specific to the M20 break in processes for cams, because let's be honest, we don't put new cams in M20s very often :)

Two things worth considering in my particular break in processes

• The head gasket failed and my oil drained out looking like the sweetest milk chocolate you've ever seen.
• My E30 is not my DD, and is used mostly for weekend fun and a few track days a year. As such, I tend to stick to oil changes between every track day and just use dyno oil (I run synthetic in my E46).

My current plan is such:

1. Moly-Lube the new cam. I can't find info on whether an M20 needs this, but I don't think it can hurt...much.
2. Start with 10w-40 GTX, run car 0.5 miles around block, drain out. For whatever reason I have some sitting in the garage, and flushing the rest of the chocolate out of my system seems like a good use for it.
3. Replace bad oil with VR1 15w-50 regular oil. The ZDDP appears to be pretty high (1300).

Questions:

1. If I flush the system with the GTX, should I just keep running the VR1 until the next oil change, or should I replace it within a much shorter timeframe?
2. Should I add something to the oil to assist with breaking in the cam and rockers?

Thanks for reading!

[digger]

prime the oil

use moly lube on surfaces is good idea

you need to run the cam at about 2500rpm as soon as it starts for like 20min dont let it idle (idle is harder on the contact surfaces). its a good idea to vary it abit from 2000-3000rpm not keep it steady

you can use a proper breakin oil like one of the Brad Penn oils if you are worried

[Earendil]

prime the oil

use moly lube on surfaces is good idea

you need to run the cam at about 2500rpm as soon as it starts for like 20min dont let it idle (idle is harder on the contact surfaces). its a good idea to vary it abit from 2000-3000rpm not keep it steady

you can use a proper breakin oil like one of the Brad Penn oils if you are worried

Thanks for the info! One clarification though; when you say "prime the oil" do you mean add an engine break-in additive, or does that mean something else?

[SkiFree]

Digger's pretty much nailed it.

[dude8383]

This may sound a bit silly... but if he pulled the head off etc and is essentially firing this motor up for the first time won't the coolant system need to be bled? How is he going to run the motor at 2500-3k for 20min without overheating... IF the system has air in it? Genuinely curious here!

[Earendil]

This may sound a bit silly... but if he pulled the head off etc and is essentially firing this motor up for the first time won't the coolant system need to be bled? How is he going to run the motor at 2500-3k for 20min without overheating... IF the system has air in it? Genuinely curious here!

This guy here! I probably wouldn't have thought to ask that until I was 30 seconds from starting and running through my checklist :)

Perhaps I need to try and recruit a friend to bleed the system while I'm keeping the RPM at 2500?

[nando]

use the throttle stop screw to hold open the throttle while you bleed it. no big deal.

I don't think you need to drive it, in fact I wouldn't.

also, by "prime the oil" I think he means prime the oil pump.

[AndrewBird]

To prime the oil pump, pull the coil wire and crank the engine over. Then replace the coil wire when you want to start the engine.

[digger]

prime the oil pump not the oil whoops

[nando]

To prime the oil pump, pull the coil wire and crank the engine over. Then replace the coil wire when you want to start the engine.

Even better, remove the cap for the oil pump drive shaft and prime the pump directly using a drill.

(Sorry, hit "edit" instead of "quote")

[Earendil]

Even better, remove the cap for the oil pump drive shaft and prime the pump directly using a drill.

(Sorry, hit "edit" instead of "quote")

Procedurally, I have a lot to learn. But I didn't think there was a piece of my car left that I wasn't aware existed, and you just named one. Where is this "oil pump drive" cap, and what is it used for? Google image searching isn't helping me out here.

[nando]

Its where the old mechanical distributor went, drivers side of the engine, just above the pump. A diagram on realoem will help visualize.

[jlevie]

You have time to bleed the cooling system while the engine is coming up to temperature. You don't want to go to 2500rpm until the engine is at normal temperature.

[whodwho]

My take on this 8^)

Being it is not a new motor not sure it needs to be primed but never hurts to get good oil circulated thru

First there wasn't mention of if this is just a stock cam or a high lift one. Stock you won't need to be as critical but I think should still be observed. You just don't want it to idle for the first 20ish mins, I'm not sure that it needs to be up to 3k but I hold between 2-2.5k

This also doesn't need to be in one shot, you can fire it up keep it r3vved up and shut it down for whatever reason like address leaks, overheating, change the oil if it is that contaminated and start back up keeping it r3vved up in one or multiple sessions for a total of the 20ish mins.

[digger]

. You don't want to go to 2500rpm until the engine is at normal temperature.

ive seen cam manufacturers recommend to do it as soon as it starts not wait what would probably be 10min

i agree on a performnace cam with stiffer valve springs it is alot more important