How hard should a rebuilt motor be to turn? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


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

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 01-11-2014, 10:52 PM   #1
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: Delhi CA
Posts: 91
Total Cats: 0
Default How hard should a rebuilt motor be to turn?

Hello, I have rebuilt a 1.8 motor with 9.0:1 supertech pistons and ACL bearings. As I have been building the motor I would turn it by the crank bolt and and a 1/2" ratchet. It always seemed to easy to turn, however, once I installed the motor and transmission into the car won't turn over easily.

I removed and tested the starter, it checked out fine. The motor turns easily until it I hit about 270 degrees, then it becomes hard to turn. I removed the spark plugs to see if it made it any easier, no difference.

Today, I removed the transmission to looks for signs of metal on metal contact. I haven't seen any, but I am tired and its dark. I will do a closer inspection tomorrow in the daylight. But I was able to turn the motor by hand a little easier. I can turn the transmission input shaft by hand easily.

My question is how much resistance should there be in turning the motor by hand? Also, is there anything that can obstruct the flywheel from turning once the transmission is attatched?

Thank you in advance.
Gregor is offline   Reply With Quote
Old 01-11-2014, 11:40 PM   #2
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

valve problem?
piston to valve contact?
JasonC SBB is offline   Reply With Quote
Old 01-12-2014, 12:59 AM   #3
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,185
Total Cats: 2,582
Default

should turn over fine. mine had zero issue being turned with a small ratchet
18psi is offline   Reply With Quote
Old 01-12-2014, 02:18 AM   #4
Elite Member
 
Join Date: Apr 2010
Location: Newcastle, Australia
Posts: 2,639
Total Cats: 25
Default

Sparkplugs in or out?

Dann
nitrodann is online now   Reply With Quote
Old 01-12-2014, 02:33 AM   #5
Senior Member
iTrader: (4)
 
2manyhobyz's Avatar
 
Join Date: Feb 2011
Location: Joliet, IL
Posts: 622
Total Cats: 16
Default

Timing belt too tight? The 1/2" ratchet was fully assembled motor on the engine stand?
Stock valve train?
Hydraulic lifter weirdness?
So the motor went in, and then the starter was used to prime the oil pump and pressurize the system?
Sorry, just more questions.
2manyhobyz is offline   Reply With Quote
Old 01-12-2014, 09:50 AM   #6
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 5,684
Total Cats: 555
Default

Should turn over easily by hand without the plugs. Accessories such as P/S, alternator, etc. should only add minimal resistance.

Sounds to me like you have some interference in the transmission to engine. Either installed crooked, so it binds, or the flywheel is rubbing.
rleete is offline   Reply With Quote
Old 01-12-2014, 10:13 AM   #7
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

Are you in neutral?
curly is offline   Reply With Quote
Old 01-12-2014, 11:59 AM   #8
Junior Member
 
guttedmiata's Avatar
 
Join Date: Sep 2012
Posts: 438
Total Cats: -3
Default

Do you people even read the original post before you ask these questions? How can you expect to give any assistance at all whatsoever with his problem if you can't even read. Yeah, bet he want to take your advice or suggestions.

To the OP, why did you start with the starter? What happened when you tried to turn the motor over with the key? It just seemed so spin slow, or was their any noise?

Sounds like interference somewhere in the clutch, flywheel, starter area. Then again, it's kind of hard to know the way you talk about the motor turning over. At this point now that you have the sparkplugs pulled and the transmission down you said the motor turns easier, but almost sounds like you are still concerned with how it turns.

With no plugs, no tranny, and no belts, you should probably be able to turn it with a 3/8" ratchet, so a 1/2" ratchet should be with only a little resistance twice in the rotation as you reach TDC and push the compression out the sparkplug hole.
guttedmiata is offline   Reply With Quote
Old 01-12-2014, 01:26 PM   #9
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 5,684
Total Cats: 555
Default

Quote:
Originally Posted by guttedmiata View Post
With no plugs, no tranny, and no belts, you should probably be able to turn it with a 3/8" ratchet, so a 1/2" ratchet should be with only a little resistance twice in the rotation as you reach TDC and push the compression out the sparkplug hole.
No plugs, no compression. You should be able to turn it with no resistance at all, except for the valve springs. If not, the engine is messed up.
rleete is offline   Reply With Quote
Old 01-12-2014, 03:04 PM   #10
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: Delhi CA
Posts: 91
Total Cats: 0
Default

Quote:
Originally Posted by guttedmiata View Post
To the OP, why did you start with the starter? What happened when you tried to turn the motor over with the key? It just seemed so spin slow, or was their any noise?

When I tried to start the car, there was a metal scraping/grinding sound coming from the starter/bellhousing area. My original idea was that the starter wasn't aligned or the transmission could be misaligned.

"Are you in neutral?"

I attempted to start the car in neutral and with the clutched pressed in. I had the same result in both cases.

"Timing belt too tight? The 1/2" ratchet was fully assembled motor on the engine stand?
Stock valve train?
Hydraulic lifter weirdness?
So the motor went in, and then the starter was used to prime the oil pump and pressurize the system?
Sorry, just more questions."

Not sure how the timing belt could be on too tight, I thought the belt tensioner was spring actuated. The 1/2" ratchet was on the engine stand initially. I made sure the motor was easy to turn after added any major assembly piece during the build, ie: pistons, head, timing belt.
Yes, stock valve train.
Not sure what you mean by hydraulic lifter weirdness, I disassembled the HLA's, cleaned them and put them back together in the same spot they came out of.
I wasn't aware of needing to prime the oil pump, used Lucas engine assembly lube on everything during the build.

Its almost warm enough for me to go back under the car, thank you for your suggestions and I'll updated the thread as I find out more.
Gregor is offline   Reply With Quote
Old 01-12-2014, 04:17 PM   #11
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 5,684
Total Cats: 555
Default

Something misaligned with the flywheel is my first guess.
rleete is offline   Reply With Quote
Old 01-12-2014, 04:28 PM   #12
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,185
Total Cats: 2,582
Default

Quote:
Originally Posted by Gregor View Post
When I tried to start the car, there was a metal scraping/grinding sound coming from the starter/bellhousing area.
if it turns over by hand out of the car, and the trans turns over, and you heard that sound, then its fairly obvious to me that the starter may have been the culprit.

Unless you dropped something in there I do not see how anything else might interfere with the flywheel
18psi is offline   Reply With Quote
Old 01-12-2014, 06:59 PM   #13
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: Delhi CA
Posts: 91
Total Cats: 0
Default

I inspected the bellhousing area, no metal shavings or signs of metal on metal contact. I going to start taking off the accessory belts and check the timing belt.





This is the point at which the motor becomes difficult to turn. After the timing marks hit the 12 o'clock position, the motor turns with little to no resistance.

Attached Thumbnails
How hard should a rebuilt motor be to turn?-259e3d74-9a53-4190-85b7-f95b0aab22a7.jpg   How hard should a rebuilt motor be to turn?-ea65d2bc-bd10-43fa-a418-440dbf71d4ae.jpg   How hard should a rebuilt motor be to turn?-7dda2757-b76b-4287-9964-fa7d099478bd.jpg  
Gregor is offline   Reply With Quote
Old 01-12-2014, 08:47 PM   #14
Elite Member
iTrader: (2)
 
Join Date: Dec 2011
Posts: 1,512
Total Cats: 142
Default

Quote:
Originally Posted by Gregor View Post
I inspected the bellhousing area, no metal shavings or signs of metal on metal contact. I going to start taking off the accessory belts and check the timing belt.

...

This is the point at which the motor becomes difficult to turn. After the timing marks hit the 12 o'clock position, the motor turns with little to no resistance.

...
Just to be clear . . . you have now taken the tranny and starter back off and it is still difficult to turn over?

The engine is basically back to the way it was on the stand, only it's installed in the car, yet it has now become difficult to turn EVEN WITH THE STARTER AND TRANNY NOW OUT OF THE EQUATION?

If that is the case, then something is messed up in the motor or perhaps a socket/wrench/bolt/etc. fell down into the timing belt area and became entangled with the belt/pulleys when you tilted the motor reinstalling it? WAG
good2go is offline   Reply With Quote
Old 01-12-2014, 10:00 PM   #15
Junior Member
Thread Starter
 
Join Date: Jun 2008
Location: Delhi CA
Posts: 91
Total Cats: 0
Default

With the starter and transmission out the motor, it was still hard to turn, but only once. After that, I couldn't replicate the problem. I am stumped(not that I'm a very experience mechanic anyway.)

The timing belt is aligned properly. I loosened and re-tightened the tensioner pulley just in case. I will start to put the car back together this week little by little after work.

Thank you for all your input. I will still post here, hopefully it will start this time.
Gregor is offline   Reply With Quote
Old 01-13-2014, 09:23 AM   #16
Elite Member
iTrader: (17)
 
Join Date: Aug 2007
Location: Fort Myers, FL
Posts: 2,791
Total Cats: 130
Default

I dropped a small socket down between the crank pulley and timing belt without noticing it one time. The motor turned over fine until it pinched the socket between the belt and pulley and completely stopped. That's probably not the issue, but it might be worth checking to see if something found it's way down there.
pdexta is offline   Reply With Quote
Old 01-16-2014, 07:23 PM   #17
Junior Member
 
Join Date: Sep 2012
Location: grants pass oregon
Posts: 81
Total Cats: -25
Default

How many ft/lbs did you torque your pressure plate bolts too
kman456 is offline   Reply With Quote
Old 01-16-2014, 07:25 PM   #18
Junior Member
 
Join Date: Sep 2012
Location: grants pass oregon
Posts: 81
Total Cats: -25
Default

How did crankshaft look when you took it out. I rebuilt small block Chevy that had a scar that I didn't catch and bearing would grab on that journal and made it hard to turn over.
kman456 is offline   Reply With Quote
Old 01-16-2014, 08:34 PM   #19
Senior Member
iTrader: (2)
 
Join Date: Oct 2011
Location: Hickory, NC
Posts: 683
Total Cats: 3
Default

It definitely sounds like you need to break the motor down and find the problem. With the starter and trans out of the equation you know the resistance you last felt was from the engine side of things. I would start with accessories and see if they turn freely. Water pumps go bad all the time so I would try ti find the problem with PS/AC/WP, then remove timing belt covers. If you do not identify the problem then I would break the engine down completely and start over. I like to take lots of pictures to both document what I did for potential resale and so I can look at my pictures and see that I did use assembly lube on every bearing surface, every connecting rod has TWO nuts, main caps, yada yada yada....

PLEASE find it, and make sure you tell us what the problem was so we can all learn from this.
Amellrotts is offline   Reply With Quote
Old 01-16-2014, 09:15 PM   #20
Senior Member
iTrader: (1)
 
Join Date: Mar 2008
Location: Cromwell CT
Posts: 1,106
Total Cats: 48
Default

Did you disable your clutch switch? you could have killed the thrust bearings on initial startup and now its hard to turn.
ctdrftna is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1991 special edition with hard top full part out JC, NJ russian Miata parts for sale/trade 6 10-08-2015 04:01 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Odd Steering issue interestedofold Suspension, Brakes, Drivetrain 5 09-29-2015 02:42 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:17 AM.