Unbalanced engine?

[itlives]

I've had my 2.3 ('87) bored out .030 and align bored. The machine shop said the crank only need polishing. I put it back together. I put the rods back in the same cylinders they came from. New pistons. Balanced flywheel.

This engine cranks right away and idles like a dream. When it gets above 2500 rpm, the vibration starts, and get progressively worse as the rpm's increase.
Do these engines have a problem with being out of balance. I am at my wits-end with this.
I'm fixing to take the engine back out and apart to have the crank checked. I'm going to make sure the rods are balanced.

Does anyone have any hard won wisdom in this area? I would appreciate any help. Mike

 

[4b316]

Did you get the balance shaft back in the right spot?Sometimes the front crank hub gets loose.New clutch and pressure plate?Did you weight the new piston assembly before putting together?We always get the rotating assembly balanced while its apart.

 

[chilsam]

87 balance shaft?

there is an aux shaft for dis and oil pump drive? Maybe cam belt a tooth off or aux shaft dist drive mite b a tooth off try adj timing with dis adv or ret.While running pull plug wires off 1 at a time to see if all cyl's are effected at rpm speed,check HB to make sure it's good or keyway was installed "chit happens" these are all thing's that can be done without disassembly of motor and check ecm also as well as all sensors and connections. GOOD LUCK!

 

[itlives]

there is an aux shaft for dis and oil pump drive? Maybe cam belt a tooth off or aux shaft dist drive mite b a tooth off try adj timing with dis adv or ret.While running pull plug wires off 1 at a time to see if all cyl's are effected at rpm speed,check HB to make sure it's good or keyway was installed "chit happens" these are all thing's that can be done without disassembly of motor and check ecm also as well as all sensors and connections. GOOD LUCK!

The guy that did all the wiring used to race these engines. He set the timing belt and timing and hooked up the dizzy to the coil and "blue" (?) box.
The only sensors are oil pressure and water temp - no ECM. This is in my 1971 VW truck (over in "Other Conversions").

I tried to keep it as simple as I could. I'm going to see my brother (also a dirt track guy) today. Maybe a new perspective is what I need.

I'll report back..... thanks guys! - Mike

 

[itlives]

Back from my brothers' shop. He said I have a collapsed motor mount. I'll replace both of them. That should help a lot!

He also said he thinks the engine sounds and feels good to him. That was good news to me.

 

[chilsam]

Excellent!

 

[armadillon]

I had a 5.0 Mustang and a bad motor mount. When I revved the motor it could sometimes tap the hood. Sadly it took me a little longer than it should have to figure it out

 

[Mark_88]

That's actually good news...I was thinking about drive shafts and other things when I first read about the vibration...wouldn't have thought of a motor mount...

 

[itlives]

Which brings to mine my motor mounts. I'll have to post a picture of them.
I can't find them on-line.
They have-
One nut on the top
Two 10mm bolts on the bottom
The pictures I see on-line have the metal parts on them and I can't actually see what the bottom looks like.
Anyway- I'll post a couple of pictures later.

 

[Insanejughead]

Every 2.3 that I've owned runs smoother as it revs higher and higher... That is, until the lifters start floating. Hahaha!

 

[itlives]

I used to float the valves in my Celica - it was great!

I found the motor mounts at Summit Racing. The pass. side is a T-Bird and the drivers side is a Ranger- go figure!
I'll report back with results (good, I hope!)

 

[shane96ranger]

I had a 5.0 Mustang and a bad motor mount. When I revved the motor it could sometimes tap the hood. Sadly it took me a little longer than it should have to figure it out

When mine broke on my Mustang, the fan was hitting the shroud. That took me a while to figure out too.

 

[Joe Lemay]

Any chance you could be over looking a weak coil. You start putting the pedal to it , it gets harder to fire. I just went throu this with my turbo 2.3. right at 2500 I thought the turbo was blowing out the flame.
I may be way off. Just hate to see you brake down a good motor.

 

[itlives]

Joe, thanks for the input. The engine is really responsive all the way through the power band. I got the new motor mount in and it helped a little. I really think it's just the "tin can" I'm driving.
I got some Fat Mat and am slowly getting the vibration sounds to go away. I no longer think it's the engine -that's a relief!

I'm reall enjoying driving this old truck and surprising people with how fast I can pull away away from a stop light!
I am doing about 3,100 rpm at 60 MPH so unless I have some re-gearing done to my transmission or put taller tires on the rear, I'm still stuck going a little slower than I want.
It's a good engine and I have no regrets doing all the work I did!

 

[Mark_88]

I was wondering how you made out...14 days or so and no update.... lol

Good to hear it's letting you break local speed laws...