Hi,

I just a got an 89 prelude 2.0 SI 4WS, with the jdm b20a in it. It rattles A LOT inside from 1000rpm-3000rpm. at idle it's fine, 3200+ it's fine, maybe a little loud but I think that's a different issue (boomy like it has an exhaust leak? which. Previous owner said they put stiffer mounts into it, and doing a little research a I found this thread New engine mounts and vibration - Honda Prelude Forum
This sounds just like my issue, and ultimately removing the stiff mounts reduced vibrations. However, I need mounts for the b20a. I keep coming across innovative mounts 29151-75A but I don't think those are the ones I want. I want OEM style mounts which I suppose are a little softer. Does anyone know where I can get mounts for a 2.0 si 4ws 1989 prelude with a b20a swapped in? or does jdm vs usdm not matter so long as they are for the 2.0 si model? That thread is the closest I came to what I was looking for, but I'm not sure that guy has a swapped motor or not. Thanks.

 

Bump
found this:
https://www.preludepower.com/threads...thread.309666/
it says

"
Bolt in Motor swaps:

1. B20A(JDM) - Si 88-89
2. B20a5(USDM) Si 88-89 and some Si models in the 90-91's
3. B21A(JDM) - Si 90-91
4. B21a1(USDM) Si 90-91
5. B20a3(USDM) - carburated -88-89
6. B20a9(EDM) Si ?? I forget
7. B20a7 (EDM) - 150hp
8. B20a6 -(ADM) - 146hp

*All motors above are bolt in motors no moddification needed for 88-91 Preludes. Some may need a different driver side mount but that is it. The 90-91 drive side mounts are different than the 88-89;however, the bolt locations for either mount are predrilled from the fatory.
"

That seems to be saying I can use the same mounts for either b20a5 or b20a, so long as it's for the right year.

 

yes, the mounts are all the same for the b20 variants. B21 mounts are the ones that are slightly different. Buying new mounts might be hit or miss, as a lot of the ones you can get at parts stores and rockauto don't fit 100% correctly. Your best bet if you do want to replace the mounts is to buy used ones, either from a junkyard, or from a facebook group. On fb, just search "3rd gen prelude" and you'll get a list of several groups dedicated to it, and you can post a want ads in them. I'm a mod for several of the fb groups.

Before anything though, I would take a peek at the mounts currently installed in the car and see if they are in fact aftermarket or stock. If they are stock, someone may have filled them with eurethane, or they may be broken. If they are stock and are broken, an easy fix is to actually fix them by filling them with 3m WindowWeld, which is a eurethane that cures to a similar hardness as the stock rubber and also glues the broken pieces back together