Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by: KPower

Built engine wont turn when gearbox gets tightened up

Thread Tools
 
Search this Thread
 
Old 05-18-2014, 06:30 PM
  #1  
Senior Member
Thread Starter
iTrader: (1)
 
NiklasFalk's Avatar
 
Join Date: Jun 2006
Location: Sweden
Posts: 1,391
Total Cats: 63
Default Built engine wont turn when gearbox gets tightened up

I need some suggestion since this is the second time this happens when the built engine goes back in.

After a lot of cursing the mating was successful (one of the guides usually misbehaves), and then all the fighting with the AWR mounts (softest bushings this time).
So when tightening the gearbox and starter up I just tried to turn the engine by hand to verify and it's stuck.
Loosening the gearbox+starter just a little makes it turn just as it was in the stand.
The clutch pack is a SuperMiata single race clutch and I never had this problems before we build the bottom end. 5speed with Mazda semi-straight gears and a 02 block.

I don't remember if I left it loose last time or tightened it after some minutes of running (the current plan for tomorrow (some hours of wrenching left before startup).

Is something just misaligned and it will shake in place or is the gearbox input shaft bottoming in the crank (but wouldn't that require the thrust bearing and oil pump to be terribly wrong)?
The stock engine I use for inspections just falls in place on its own now so this is something specific to this engine (same clutch was use before it was built and I don't think I had this problem then).
NiklasFalk is offline  
Old 05-18-2014, 11:16 PM
  #2  
Former Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Default

Check the pilot bearing alignment in the flywheel. If it's out, the input shaft presses up against it, doesn't press onto it, and nothing will turn.
Savington is offline  
Old 05-19-2014, 10:27 AM
  #3  
Senior Member
Thread Starter
iTrader: (1)
 
NiklasFalk's Avatar
 
Join Date: Jun 2006
Location: Sweden
Posts: 1,391
Total Cats: 63
Default

Thanks for pointing out what I've missed.
The pilot bearing was installed flush but could be tapped in another.05" or so.
Now it's back in there and I only have to fight with one dowel pin and the pesky engine mounts.
NiklasFalk is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Full_Tilt_Boogie
Build Threads
84
04-12-2021 04:21 PM
90 Turbo
MEGAsquirt
19
10-19-2015 03:23 PM
lsc224
Miata parts for sale/trade
2
10-01-2015 09:17 AM
mx592
Suspension, Brakes, Drivetrain
1
10-01-2015 12:45 AM
shooterschmidty
Engine Performance
8
09-30-2015 10:28 PM



Quick Reply: Built engine wont turn when gearbox gets tightened up



All times are GMT -4. The time now is 12:28 AM.