While im in there...

[NC325iC]

So i have the stroker out of the car on an engine stand. Before when i was driving it i was experiencing what i believe was pinging on throttle >1/2 in mid rpm range (was running on motronic). I would like to check over the engine as much as i can before i put it back in a car and MS it. Where should i start?

I was thinking:

Pull head to check chambers/pistons for any signs of problems
pull oil pan to check bearings

my questions,
-if i pull the head do i 100% need to get it surfaced?
-to check the bearings for excessive wear would i need to remove them or would a good visual inspection suffice?
-anything else to check?
-should i even do this?

all the obvious parts to change are already being changed.

edit: about the pinging, if you lay into the throttle more than half way you would hear it up till about 4k rpm then it would go away (obviously i avoided doing this as much as possible). i always ran 93 in this engine, cooling system works fine never above 1/4 mark. compression is 10.3:1.

[NC325iC]

anyone

[jlevie]

my questions,
-if i pull the head do i 100% need to get it surfaced?
-to check the bearings for excessive wear would i need to remove them or would a good visual inspection suffice?
-anything else to check?
-should i even do this?

If you pull the head, you should have it checked for flatness. If it is flat there is no reason to have it surfaced.

To check the bearings you need to check for scoring or wiping and measure the crank journals and bearing ID's and compare that to wear specs. Since you have to remove the crank to do that, if you are going to tear down the engine that far you might as well have the crank polished, measured for diameter and fit new bearings of the appropriate size.

And if you pull the crank you might as well pull the pistons and gage the bores. If withing wear limits, have the cylinders honed and reassemble with new rights. While the pistons are out have the wrist pin bearings replaced and reamed.

The other choice is to not mess with the engine at all. If you were running a 10.3 compression ratio with a Motronic 1.3 DME, it would not be surprising that the engine pinged. You'd have to have a custom chip to get enough timing advance for that compression ratio.

[CorvallisBMW]

The other choice is to not mess with the engine at all. If you were running a 10.3 compression ratio with a Motronic 1.3 DME, it would not be surprising that the engine pinged. You'd have to have a custom chip to get enough timing advance for that compression ratio.

I'd say this is a good bet. Unless you're running standalone EM the engine is bound to ping some with a high compression ratio. You could pull the head just to look around, or rent a boroscope and do it that way.

[NC325iC]

thanks guys, i ran a custom markd chip that he made for me based on the engine specs, with the same problem. When we bought the engine from Pete he said itd be ok to drive on M1.3 so I did. Ill have a good look around and see if i can find any external reasons to open the engine up, if not ill leave it be and save that money for more tuning.

didnt mention that the engine only has like 40-50k miles on it

thanks again