View source for M30 Engine Rebuild Tips & FAQ

These do not apply solely to an M30B35 swap, they work for all M30 builds. Content originally from: [https://forums.mye28.com/viewtopic.php?t=125377 M30 Engine Rebuild Tips & FAQ]

== Q: What other sources of good info are there? ==

* [https://us.haynes.com/collections/bmw-car-manuals/products/bmw-3-5-series-82-92-haynes-repair-manual Haynes BMW 3- & 5-Series Manual,] particularly "Chapter 2 Part B: General engine overhaul procedures".

== Q: What's the best order of assembly of an M30 motor? ==

If you don't follow this order you will likely end up re-doing work.

# Oil pump and chain.
# Lower timing chain sprocket, guides, and timing chain.
# Lower timing chain cover. Don't forget to install the brackets for the timing sensor and shackle.
# Grub screw, AC compressor mount, PS/Alternator mount
# Rear main seal.
# Oil pan
# Install harmonic balancer temporarily so you can see crank TDC. NOTE: in my pic above I am NOT at TDC. The crank dowel pointing up DOES NOT indicate TDC.
# Set head to camshaft TDC before installing. TDC means the small dowel pin on camshaft is down and the two face bolts are aligned vertically.
# Head.
# Upper timing chain cover
# The rest is straight forward

The Haynes Manual has this order:

# Piston rings
# Crankshaft and main bearings
# Piston/connecting rod assemblies
# Oil pump
# Sump
# Cylinder head assembly
# Timing belt or chain and tensioner assemblies
# Water pump
# Timing belt or chain covers
# Intake and exhaust manifolds
# Valve cover
# Engine rear plate
# Flywheel/driveplate

== Q: I've never mounted an engine on an engine stand before. What bolt holes are best to use for an M30? ==
Bolt holes 12, 4, 5 & 7. The AL piece just allows easy inspection of the flywheel. It won't hold any serious load.

== Q: Should I take the flywheel off first? ==
Yes!

== Q: How'd you get the Jesus nut (crank) off? ==
With a good air compressor and impact wrench, I just pounded away for about 2 minutes with a 36mm impact socket. Others have heated it up and used a breaker bar.

The crank nut can be removed with the motor still in the car. I purchased an m30 hub holder from bavauto (about $80, if I recall) and a 4:1 torque multiplier. I removed the radiator and loosened the condenser mounting bolts to get as much clearance for the tools as possible.<!-- IMPORTANT: DO NOT FORGET TO TORQUE THE NUT BACK ON PROPERLY. -->

== Q: What's the best way to clean caked on grime and cosmolilne off aluminum and plastic parts? ==
Soda blasting! Careful on the plastic to use a mild grain soda because it WILL make the plastic slightly more matte.

[url=<nowiki>https://flic.kr/p/eFP3D9</nowiki>][img]<nowiki>https://farm8.staticflickr.com/7355/8983160474_77307fe081.jpg</nowiki>[/img][/url]

Before:

[url=<nowiki>http://www.flickr.com/photos/ckindel/8983163794/</nowiki>][img]<nowiki>http://farm6.staticflickr.com/5444/8983163794_1f1e5dd0ed_b.jpg</nowiki>[/img][/url]

After:

[url=<nowiki>http://www.flickr.com/photos/ckindel/8981970779/</nowiki>][img]<nowiki>http://farm4.staticflickr.com/3729/8981970779_500e27210e_b.jpg</nowiki>[/img][/url]

[img]<nowiki>http://farm6.staticflickr.com/5451/8981967739_9b75155e00_b.jpg</nowiki>[/img]

A few minutes later:

[img]<nowiki>http://farm8.staticflickr.com/7435/8981970259_f7f79e4eb7_b.jpg</nowiki>[/img]

[i]DO NOT USE A SAND OR MEDIA BLASTER FOR INTERNAL ENGINE PARTS. Those kinds of media will never come out and they will do what they were designed to do (abrade) when the engine runs.[/i]

== Q: Are any of the fasteners on the engine (crank, camshaft, etc...) reverse threaded? ==
A: No

[b]Q: Where can I get my fastners "zinc" plated?[/b]

A: www.arrowplating.com in Ft. Worth did a great job for me. I spent bout $60 including shipping for two sets of fasteners (I had two donor motors).

Don't include any stainless steel (hose clamps) or aluminum parts!

[img]<nowiki>http://farm3.staticflickr.com/2859/10719789774_717292723b_b.jpg</nowiki>[/img]

[img]<nowiki>http://farm8.staticflickr.com/7394/11075920856_14bb731e93_b.jpg</nowiki>[/img]

Note that many of your M6 wave washers will die a horrible death in the plating process (they are thin and the plating process weakens them, apparently), so buy extras.

== Q: How do you keep what fastners go where straight? ==
A: I used the following combination of techniques:

First, I took tons of pictures of the donor motors from all angles before and during dis-assembly. I also created a thread here for others to post their own pictures for additional reference: <nowiki>http://www.mye28.com/viewtopic.php?t=117074&highlight=</nowiki>

I put everything in zip locks when I tore down the donor motor and labeled the zip locks. Later I took pictures of the fasteners laid out on the zip lock so i could have a reference, since I couldn't keep them this way for plating.

[img]<nowiki>http://farm4.staticflickr.com/3668/10719905096_7d9a3fb6d2_b.jpg</nowiki>[/img]

During re-assembly I laid all my fasteners out by size:

[img]<nowiki>https://farm8.staticflickr.com/7145/13519968233_f79010442a.jpg</nowiki>[/img]

As I needed a fastener I first checked RealOEM for the dimensions. Then I went to my set of fasteners with my ruler and picked the right fastener. I checked my photos if there was any ambiguity.

== Q: I'm missing a part. I can't find it anywhere. Where might it be? ==
Have you checked the depths of your parts washer?

== Q: Can I re-use head bolts? ==
Some say No. Some say Yes. If you use new, note they will not come with washers so save your old ones!<blockquote>Damn head bolts. For the last fricken time, our head bolts are not torque to yield and do not need replacing. The confusion is that the torque sequence includes a torque to angle step. Torque to yield bolts have large diameter threads tapering to a very narrow shank and then taper back up to a large bolt head. Torque to yield bolts must be replaced after every use. In every single case that I've run across where a torque to yield bolt is used, the torque sequence includes at least one torque to angle step in the sequence, such as torque to 50 ftlbs then an additional 90 degrees. The final torque on ours is somewhere around 60 ftlbs. and while the sequence includes a torque to angle step, it doesn't mean they are torque to yield bolts. The yield strength of an m12, grade 10.9 is 92 ft lbs lubed and 123 ftlbs dry. As you can see, at 60 ftlbs you are about 25% below the yield strength of the bolt. The difference in the lubed and dry spec illustrate the need not only to lube the bolts for proper torque but also the importance of cleaning the threads for the correct torque to be achieved. Installing dirty lubed bolts has the equivalent effect of installing them dry as the increased friction of dirty threads reduces the final torque reading. In other words if you install the bolts dry and torque them to 60 ftlbs, the actual torque is about 30% less or approximately 40 ftlbs. Since some threads are cleaner and some are dirtier the result is uneven clamping force and a propensity for warped heads and subsequent repeated head gasket failure. Replacing these head bolts is an idiotic waste of money, especially if it makes you feel good.</blockquote>

== Q: When I re-wrap the wiring harness, what kind of tape should I use? ==
F4 Tape. Buy it [url=<nowiki>http://www.amazon.com/Products-F4TapeBlack-F4-Tape-Self-fusing/dp/B002LA2258/ref=sr_1_1?tag=ceklog-20</nowiki>]here[/url].

== Q: If I need to put splices in my wiring harness what's the best splice technique? ==
If you want reliability use high quality non-insulated butt/barrel crimp connectors with a quality crimp tool. Unless your technique is perfect, soldier is too prone to failure.

[img]<nowiki>https://v4s2.yimg.com/so/7292/12865559553_c5eb6460dd_b.jpg</nowiki>[/img]

[url=<nowiki>http://www.flickr.com/photos/ckindel/13360798694/</nowiki>][img]<nowiki>http://farm8.staticflickr.com/7340/13360798694_8e0ffbbafa_b.jpg</nowiki>[/img][/url]

[url=<nowiki>http://www.flickr.com/photos/ckindel/13360418715/</nowiki>][img]<nowiki>http://farm8.staticflickr.com/7051/13360418715_743d4011dd_b.jpg</nowiki>[/img][/url]

Delcity.com calls them Barrel Butt Connectors. That's where I get them.

<nowiki>http://www.delcity.net/store/Non!insulated-Butt-Connectors/p_801870</nowiki>

<nowiki>http://www.delcity.net/store/Insulated-:-Non!Insulated-Terminal-Ratchet-Crimp-Tool/p_10426</nowiki>

TIP: If multiple wires are spliced next to each other, the added bulk can wear faster and cause failures. Stagger the splices.

== Q: The oil pan gasket has turned to diamond. How can I remove it. ==
Soak it in diesel for a day or two. it will then come off with a gasket scraper.

[img]<nowiki>http://farm8.staticflickr.com/7064/13409949763_59291ea06a_b.jpg</nowiki>[/img]

== Q: Do I need to do any prep to the surface before putting the head gasket on? ==
You want the mating surfaces to be smooth and clean. Definitely no oil. Make sure the bolt holes are clean as well.

== Q: Where and what sealants should I use to prevent leaks? ==
Sealant? Pretty much just on anything you don't want to leak. Permatex #3. Timing covers especially, but also pan, rear main seal housing, Teflon tape on the plug for the timing chain tensioner, just everywhere is close.

Toyota's Form In Place Gasket (FIPG) is also very effective.

Also some folks claim the best sealant is Hylomar. It will not harden and potentially clog fluid passages if it breaks off.

Do NOT use the red silicon shit.<blockquote>The two sealants that you will need are Permatex aviation gasket sealant and RTV silicone. Anywhere you have two mating surfaces that are free of major imperfections use the aviation gasket sealant. For example front timing cover to block, water pump to housing, etc. Anywhere there is a complex joint, such as the head/block/front timing cover joint, or anywhere there is a void to be filled, use the silicone. Additionally anywhere you have a gasket that seals a joint of two separate components, like the oil pan to block/timing cover, a small dab of silicone should be used compensate possible height differences (fill the void).</blockquote>

== Q: How do I clean my rusty ass block, and what paint can I use? ==
Elbow grease. Purple power degreaser, scrub and rinse. Any high temp engine paint is fine. However there is one step in preparing any cast iron component that needs to be taken, otherwise the paint will start flaking in short order. Cast iron is very porous and even if it is dry to the touch, it still contains moisture that needs to be removed. Enter the common propane torch. Simply play the flame on every surface of the block, head or manifold. You will see the moisture precipitate out of the metal. Additionally any remaining grease or oil will be burned off. Once the metal is truly dry you can paint and it will wick into the cast iron ensuring complete adhesion. If you leave the moisture in the metal it will precipitate out during normal heat cycling and cause the paint to flake. Light surface rust is okay, use a steel brush to remove anything more.

== Q: Timing Chain Guides: Can these be replaced without removing the actual Timing Chain itself? ==
No. Or at least I can't imagine how you could.

== Q: How hard is it to remove the Timing Chain itself? ==
Easy, but you have to remove both the front covers and the camshaft sprocket. I suspect you'll want to go ahead and do the head gasket if you go this far.

== Q: Should one powder coat the Oil Pan and Differential Cover or is this not recommended due to heat dissipation issues? ==
I have been running a powdercoated oil pan and rear diff cover for close to 10 years with no problems. I would say go for it if that is what you desire!

[[Category:Tech FAQ]]