• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

knock at low rpm


AvlAndrew

Active Member
Joined
Sep 4, 2021
Messages
27
Reaction score
10
Location
Asheville,NC
Vehicle Year
1990
Make / Model
Ford Bronco ii
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
I just repaired a 90 B2 engine, that had a bent intake valve due to a bad fuel injector
so re-installed the engine, its running smoothly, but there is a knock at idle from what seems like the bottom end where the oil pump is located. this knock goes away at 2k rpm. I am inclined to replace the oil pump.. any suggestions appreciated.
 


MaicoDoug

Well-Known Member
U.S. Military - Veteran
Ham Radio Operator
GMRS Radio License
Joined
Sep 13, 2020
Messages
590
Reaction score
470
Location
Texas
Vehicle Year
2007
Make / Model
Ranger FX4 LVL2
Engine Type
4.0 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
2 inches in the back, not enough in the front
Tire Size
32x11.5x15
Well you know there are other things that make knocking sounds down there for instance there is always the infamous "rod knock" connecting rod not happy with it's fit with the wrist pin and / or the crankshaft. The first thing I would do is install some heavy weight additive oil and listen again. The increased viscosity should change the sound if it's oil related. New oil filter installed I hope. Also looking for an extended "dwell" at TDC watching at the piston with the head removed with a dial indicator. I really hope these helps with the noise, something tells me that it will. The distrubritor also has stuff moving around down there like it's drive gear if so equipped. Excessive shaft end play is how that wears out.
 

AvlAndrew

Active Member
Joined
Sep 4, 2021
Messages
27
Reaction score
10
Location
Asheville,NC
Vehicle Year
1990
Make / Model
Ford Bronco ii
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
i installed a new oil pump, will fire it up tomm and see if that was the issue.
 

AvlAndrew

Active Member
Joined
Sep 4, 2021
Messages
27
Reaction score
10
Location
Asheville,NC
Vehicle Year
1990
Make / Model
Ford Bronco ii
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
still same knock, possible crank shaft bearing cylinder 3
 

MaicoDoug

Well-Known Member
U.S. Military - Veteran
Ham Radio Operator
GMRS Radio License
Joined
Sep 13, 2020
Messages
590
Reaction score
470
Location
Texas
Vehicle Year
2007
Make / Model
Ranger FX4 LVL2
Engine Type
4.0 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
2 inches in the back, not enough in the front
Tire Size
32x11.5x15
Try increasing the oil viscosity with a bottom end treatment such as motor honey or the like. That will make the sound go away quite a bit. Doing this should help you trouble shoot the crankshaft and connecting rod excess clearance knock issues.
 

Sponsored Ad


Sponsored Ad

Staff online

Today's birthdays

TRS Events

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Latest posts

Truck of The Month


Rick W
October Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Vagabond Video

25th Anniversary Merch

Follow TRS On Instagram

25th Anniversary Sponsors

TRS-3 Ford Ranger Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top