M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: benhanson on February 19, 2007, 05:19:31 PM
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Well I've bitten the bullet and started my engine rebuild. I parked my '91 318i last fall, thinking I may have broken a ring or had a rod knocking. Turns out it was the right timing chain guid had been cracked, and finally came apart, making all kinds of growling/clacking noises.
Currently I have the engine all apart and I'm in the inspection phase. I'm trying to determine how much money I'll be putting out, just so I know before I start buying parts.
So my inspection questions are as follows:
1. Cam and Bearing Ledge:
I removed the cam without the special tool, didn't read the manual first(Live and learn). Now I'm trying to figure out how to inspect the cam and ledges to be sure all is OK. Any hints?
2. Cylinder bores:
Before the teardown, compression test showed around 145-147 on cylinders 1, 3 and 4, with cylinder 2 at about 118. Now with the engine apart, I can feel some very mild scoring in cylinder 2. How do I know if it's bad enough to need a rebore? Do I try and polish it out? The scoring isn't broad enough to be able to use a feeler gauge, and I'm not sure how to measure it.
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1. Cam and Bearing Ledge:
I removed the cam without the special tool, didn't read the manual first(Live and learn). Now I'm trying to figure out how to inspect the cam and ledges to be sure all is OK. Any hints?
2. Cylinder bores:
Before the teardown, compression test showed around 145-147 on cylinders 1, 3 and 4, with cylinder 2 at about 118. Now with the engine apart, I can feel some very mild scoring in cylinder 2. How do I know if it's bad enough to need a rebore? Do I try and polish it out? The scoring isn't broad enough to be able to use a feeler gauge, and I'm not sure how to measure it.
1. the main purpose of the special tool is to prevent the cam from snapping in half as the caps are removed. as long as this didn't happen, you SHOULD be ok. aside from that, you're really just looking for any visible wear on the lobes.
2. generally, any scoring you can feel with your fingernail is not a good thing. first thing i'd do is take the block to be cleaned & checked by a machine shop. they can tell you how much of an overbore is required so you have a better idea of what you're working with. (even BMW offers oversize pistons for this engine, but the cylinder spacing doesn't allow for much . . .)