Flexplate knocking and more. - JeepForum.com
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post #1 of 20 Old 02-02-2014, 10:39 AM Thread Starter
Bjorka
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Flexplate knocking and more.

Hi,

My Comanche -89 with 300 000km need some care...and I need some advice.

There is a hard knock under the engine and I thought it was the flexplate but the bolts was not loose at all and I can't se any cracks in the plate.!?

Here's the knock:

When I listen to the engine with a skrewdriver to the ear the sound comes somewhere from the rear of the oilpan...but it's hard to precise.

I tried to disconnect the wires to the sparkplugs one by one but I coulden't hear no difference.

Is it the mainbearings or what?

There is also a ticking or rattle during acceleration or under load.
(It's not pinging due to timing)

Could that be from bad mainbearings?

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post #2 of 20 Old 02-02-2014, 03:11 PM
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Check this link out.

http://www.cherokeeforum.com/f2/foun...emoval-171945/

If you own a Renix Jeep, you'll want to check this out.

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post #3 of 20 Old 02-02-2014, 10:32 PM Thread Starter
Bjorka
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Thanks!

But it didn't help there's no sign of any damages or cracks at all, the plate looks just perfect no worn boltholes or nothing..

I went under the car with the engine running and listen carefully and the knock seems to come more from the engine than from the flexplate area.

Last edited by Bjorka; 02-03-2014 at 02:00 PM.
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post #4 of 20 Old 02-04-2014, 01:37 PM Thread Starter
Bjorka
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The flexplate and the four bolts are ok,,,but what about the bolts in the center (which I can't se or reach from the inspection hole) Are they known for causing problems? They seem to be tightend good enough when I'm bending the flexplate no gap what so ever.
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post #5 of 20 Old 02-04-2014, 05:45 PM
Caish
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Oil pan should come off easy,
if the torque convertor bolts are titght its time to drop the pan and start checking bearings.

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post #6 of 20 Old 02-04-2014, 05:55 PM
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Quote:
Originally Posted by Bjorka View Post
The flexplate and the four bolts are ok,,,but what about the bolts in the center (which I can't se or reach from the inspection hole) Are they known for causing problems? They seem to be tightend good enough when I'm bending the flexplate no gap what so ever.
Unlikely but I guess a possibility.

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post #7 of 20 Old 02-05-2014, 01:17 PM Thread Starter
Bjorka
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Quote:
Originally Posted by Caish View Post
Oil pan should come off easy,
if the torque convertor bolts are titght its time to drop the pan and start checking bearings.
Yes, I'm already preparing my mind for it, need to find some time for it though.

Guess it will take some weeks including inspection and ordering/shipping for new parts and installation.

Is it worth to tear down the cylinderhead and check piston rings and bearings etc as well or is it overkill? I don't think they are known for problems?
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post #8 of 20 Old 02-08-2014, 10:39 PM
Caish
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Be prepared to pull the engine out if it spun a bearing and needs the crank turned.
I've got a 94, F150 sitting there, I need to pull the pan on , I sure it was an XJ I was
doing it on, a lot easier.

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post #9 of 20 Old 02-10-2014, 12:25 PM Thread Starter
Bjorka
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I started the dismantling tonight and everything went on well...but I can't get the oilpan to come down!
I have been violent and tried to bend it apart with a hammer and a skrewdriver formed as an "L" to get a good angle, but It's stuck as H...
It's even hard to get the skrewdriver in between the pan and the engine.

I can see some red stuff in the bolt holes probably some kind of heavy duty liquid gasket?

Any ideas?

Heating maybe but the risk of fire is not to play with..
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post #10 of 20 Old 02-18-2014, 01:21 PM
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Go around again and make sure you're not missing any of the bolts

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post #11 of 20 Old 02-18-2014, 03:30 PM Thread Starter
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It was the gasket..I had to use a number of wooden wedges to get the damn thing down.

The oil pump is down and it looks ok so far, can't imagine the sound comes from it any way.

Well... the bearings, here they are, worn and sometimes in the past infected with some kind of metal "dirt" ?
What about the numbers, can someone se what size I should buy?
I've messaured the crankshaft allover and it's within the tolerances given in the WSB
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Last edited by Bjorka; 02-22-2014 at 02:19 PM.
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post #12 of 20 Old 02-23-2014, 12:09 AM Thread Starter
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I usually buy autoparts from usa/ebay since the prices here in Sweden are more then twice as expensive...

Can you recommend any of the bearings in this list, I'm looking for quality.

http://www.ebay.com/sch/Engine-Beari...e+Pioneer+4.0L
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post #13 of 20 Old 07-24-2014, 01:57 AM Thread Starter
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Update

It took some time because some other stuff (life) come in between but now is the engine reassembled and as new. I did a complete major overhaul with new bearings, pistons, camshaft, oilpump, etc.


And..at first startup all knocking and pinging is gone and the engine is running smooth :-)

But one thing makes me wondering...the whole intake, and injectors was totaly black and dirty.

I find out that the oxygensensor was broken, so I put in a new one and new injectors as well. Hard to tell any difference yet but the engine needs 5sec to fire compared with almost 1sec before the changes?

(Before this major overhaul the jeep got new cps, tps, iac )
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post #14 of 20 Old 07-24-2014, 05:11 AM
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Test the CPS output voltage if you're concerned about cranking time.

Also, when reinstalling the engine, did you get the 3 or so ground wires on at teh engine dipstick tube stud? Shiny metal connection?

If you own a Renix Jeep, you'll want to check this out.

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post #15 of 20 Old 07-24-2014, 04:04 PM Thread Starter
Bjorka
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CPS is ok and the rest of the electrical also sa far as I know..
I think I have removed and replaced all vital cabels and connections regarding the engine control.

The new injectors are not exact the same as the old, but should be for this engine, can the operating pressaure be higher maybe?
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