TuneScheduled for this Saturday.
Engine MountsBack in November, on first cranking for the new engine, we heard a terrifying "thump thump thump" noise. To our great relief, this was eventually determined to be sad stock engine mounts allowing some part of the drivetrain to contact the chassis. Presumably being removed then reinstalled had allowed whatever cracks/weaknesses in the 14-year-old rubber to advance.
As a temporary solution, some 5mm thick alloy shims were fabricated and inserted. Problem solved for the time being, but not a permanent solution.
With the delay before the tune, I ordered some "Hardrace" brand engine mounts - decribed as harder than stock, but still suitable for street use.
The stock mounts seem to be some kind of plastic (with a rubber core), while the Hardrace mounts are cast aluminium (with rubber core).
[In the words of Ash from Evil Dead: "
...your primitive intellect wouldn't understand things with alloys and compositions and things with... molecular structures."]
The more common Subaru mounts seem to be "matchbox shaped" rubber rather than these Forester large round rubber mounts, if you're reading this post hopefully you still get something out of it. Time and zero R&D tolerance sent me to replacement Forester mounts, but I am curious as to how readily "matchbox shaped" WRX & STI mounts work on a Forester (and with what hardware/modifications).
Speaking of modification, spot the difference:
That's right, the tab is diagonal on the stock mounts but straight on the Hardrace aftermarket mounts.
This makes it hard/impossible for the stock metal piece (heat shield?) to fit over the Hardrace mounts. Heat shield shown at bottom of image below. Apologies for poor focus:
Being cast aluminium, it was easy to modify the shape of the tab. I used an angle grinder with a coarse flap disk (then cleaned up with a hand file and sandpaper).
Elongating the holes in the heat shield (?) also helped with assembly:
Replacing engine mounts at homeThere are plenty of Youtube and other resources on replacing Subaru engine mounts at home, so my brief notes are as follows:
1. Position the car on ramps (or spare pavers or whatever) to give reasonable working clearance within the lifting range of your trolley jack (with wooden block/s added). Raising the vehicle 100mm was good for me.
2. Remove engine cover, intercooler, one pitch-stop mount bolt and the MAF hose so the engine can raise about 50mm.
3. Remove under-tray, bracing plate and front swaybar. Despite American Youtube advice, I saw no need to remove any exhaust components.
4. Remove the single nut on the under side of each existing engine mount.
5. Loosen (but don't remove) as many bolts as you can get at between the current mounts and the engine block. I got to both passenger side bolts and one driver's side bolt.
6. Position your trolley jack under the sump. I used a piece of hardwood (for strength) with a piece of pine (for softness/conformity) on top where it touches the sump.
7. Carefully raise the engine via the sump with the trolley jack. Enough to clear the threads of the existing mounts plus the minimum extra working room you need. Remember that you are straining radiator hoses and other things here, so don't go crazy lifting the engine until something breaks.
[
SAFETY NOTE - relying on a hydraulic jack to hold a heavy object for a long time is inherently dangerous. I reduced (but did not eliminate) my risk by:
(a) keeping my hands out from between engine and chassis as much as possible;
(b) otherwise being mentally prepared to get my hands out of danger at any time the trolley jack started quitting - which never happened thankfully;
(c) for longer breaks, putting some unbolted engine mounts back in and lowering the jack so the engine rested on mounts and the chassis rail.]
8. Remove both mount-to-block bolts on the passenger/easy side and remove the current mount. Test fit the new mount. I suggest leaving the mount-to-block bolts slightly loose until you have test-lowered the engine again and are 100% sure the down-pointing thread is coming through the slot in the chassis rail. You can then tighten those mount-to-block bolts.
9. The rear mount-to-block bolt on the driver's side (Aussie right-hand-drive vehicle) is a pr!ck. You can barely see it. With the engine raised you can at least get access to it with a 14mm ring spanner. I recommend a brass hammer (or similar) to impart a sharp blow on the spanner to loosen this bolt. Post-violence, a 14mm ratchetting spanner is handy to remove this one once it is loosened.
10. Install the new driver's side mount with a similar "loose til it's confirmed to be lined up" policy. The engine is going up and coming down a few times through this process.
I found that rear driver's side bolt such a pr!ck to locate then start in its hole that I ended up grinding a chamfer onto it:
As with the passenger side, when you are 100% sure the down-pointing thread is coming through the slot in the chassis rail you can then tighten those mount-to-block bolts.
11. Lower the engine a final time and replace/tighten the nuts on the down-pointing threads and chassis rail.
11.5 At this point I pulled the fuel pump fuse and cranked the engine just to confirm no "thump thump thump" noise. Your reasons for replacing engine mounts may vary.
12. Re-install the pitch-stop mount bolt BEFORE you put your intercooler back on or you'll be taking the intercooler off again when you realise.
A bit of pure speculation there on the type of stuff-up someone less clever than me might fall victim to....13. Put all the other stuff back. If your aftermarket swaybar mounts need grease, this would be a good time for that.
Thanks for reading.