I had a clutch spring fall out on a different car a very long time ago. Drove fine, but had vibration under accel.

 

So my two problems are vibration when reving in neutral and a strange noise coming from the front of the engine while running. Not a knock knock noise but something I haven't heard before. Decided to remove alt belt since I only have one belt and to my surprise noise is gone!!.... either my old alternator or brand new gates water pump is responsible. At least I know it's not internal. Still have the vibration but will investigate further once the tranny is out.

 

I guess I like to waste time, I balance most all the performance builds I do, to .1g of mean

so pistons are that close, small end of rod and the over all of the rod

Most 4 cylinder cranks are close from the factory as far as balance goes, but they still can be better

I normally take the H-bal n bolt, time belt gear, crank, flywheel with bolts and pressure plate and bolts to be first individually balanced then balanced as a unit

I have seen rotating the pressure plate throw the balance off as much as 52g, and commonly see 20g

So once I get done with the balance job, the pressure plate is indexed to the flywheel

Now IIRC, there is some clearance work done on cyl 1 just behind the water pump on the 1.8l, so with spec stack, your new water pump shaft may be lightly touching Cyl 1

**EDIT**
Thought I did a write up on the Manley rods..
https://www.miataturbo.net/engine-pe...ng-rods-65527/

 

Thanks for the write up on the rods. I did read your entire post as I was reaserching my build. I guess my lesson learned here is listen to everyone here and not the machinist. The shop that i took my block, crank and head to is a very good shop and the guy who owns the shop is very reputable and does great work. He knew I had aftermarket forged rods but only asked for my pistons once he determimed if my block requried boring. I guess i assumed balancing the rods wasnt needed since he didnt ask for them.

The ATI Damper is quite a bit heavier than stock one would that cause anything??

On a side note I did just take it out for a 15 mile shake down and it seemed to run fine. Maybe im just being over freaked out since ive never built my own motor before and havent really given everything a chance to settle into place.

Going to change the oil for the first time tomorrow so fingers crossed everthing looks ok

 

Just a little update. I changed the oil and other than a little discoloration from all the assembly lube the oil was as clean as when I put it in with no signs of metal or shimmery bits. I'm pretty confident there's no metal on metal interference taking place. I still have a vibration around 2.5- 3k that I need to figure out but will know more after I drop the tranny and reinstall flywheel and clutch to rule that out.

 

Are you sure you haven't put the engine mounts in upside down?.....there is a metal tab that is supposed to fit in a locating hole (or something like that).....if you fit them wrong you may have metal to metal contact on each side.

 

I've checked that already but thanks for the input. When I was out driving it sounds like a heat shield ratteling under the car somewhere so I'm going to get under it again tonight. Hopefully I'll find something obvious. I noticed the down pipe contacting the shelf in the engine bay so I'm sure that is contributing to it but doubt it's solely responsible.