Engine Knock Fresh From A Rebuild

[SchmeelDeal]

Okay, here is the problem:

'92 6-Bolt Laser RS Turbo AWD 5-Spd

The engine is fresh off of a stock rebuild, not even 200 miles. When the engine is cold, everything is fine. However, after it heats up to operating temperature, a constant loud KNOCK KNOCK KNOCK starts coming from the engine. The people at the rebuild shop have no clue what could be wrong with it now. The knock sensor has been replaced (CEL put out a code for a bad knock sensor). The car has been to Mitsubishi several times and all they say is that a rod bearing is going bad, but the rod bearing are all brand new. Both shops have checked the timing and they tell me everything there is fine. Today, the rebuild shop said that the balancer shaft belt was off by two teeth, so they readjusted it and the knock is still there. Now they are saying that it is being caused by the clutch and flywheel that I had them put in (ACT 2600 Clutch w/ Street Disc & ACT Xact Streetlite Flywheel).

Can anyone give me some insight as to what the problem could be or what to check?

Thanks,

James

 

[AwdEi]

Why was it rebuilt?

 

[SchmeelDeal]

The motor was basically worn out. Had 146k on it. A piece on one of my exhaust valves broke off and a cam gear broke. The shop I took it too replaced those parts, but botched my head trying to drill out and tap broking bolts in the exhaust side of the head. The car also started having major blow by. Was going through about a quart every two days.

The body of the car is in great shape, and the tranny was rebuilt about 50k ago. So I decided to get the engine rebuilt.

 

[SchmeelDeal]

Okay problem seems to be worse now, just from driving the car 5 miles from the Mitsubishi shop. Now it knocks all the time, regardless of the engine being hot or cold and there is a really heavy vibration when the rpms are above 2500 or higher. If you push the clutch down to the floor real quick the engine rpms go way down and it has stalled a few times. Also, clutch release extremely close to the floor.

I know the crank was grinded during the rebuild, but I think that they put regular thrust bearings back in. Could this be a case of the crankwalk monster?

The shop still insists that it is the ACT flywheel and is in the process of dropping the tranny and putting the stock on back int. Flywheel was stepped to .612" before it was installed.

They refuse to even look at the crank case. Anyone have any other ideas besides the crank?

 

[leet]

Pull the oil pan and inspect your rod bearings.

 

[Logue]

i would go with leet and say its probly a rod bearing. good luck. that was my biggest fear on my rebuild too.

 

[SchmeelDeal]

Rebuild shop said they took the oil pan off and found that the bearings for the balance shaft were shot and it caused the crank to dig in the case. So they are getting me a jasper engine at no charge.

Could an unproperly installed aftermarket clutch (ACT 2600) and/or flywheel (Xact) have contributed to this? Just wondering, because I do not want this to happen again when they do the new engine.

 

[slowAWDTSi]

If they havent alrady got a jasper engine tell them not to
Jasper Engnes cannot be modfied barely at all. If you get one you cant put cams in them bacause of the way they grind the head . I had a rep come into my dads shop and i picked his brain and they suck :thumbdown
but if you dont wanna do mods it should be fine
Just trying to help
Dru

 

[SchmeelDeal]

Originally posted by slowAWDTSi
If they havent alrady got a jasper engine tell them not to
Jasper Engnes cannot be modfied barely at all.

You do mean internal engine mods right? They would void the warranty anyway, so I am not worried about it.

Anyone know if Jasper engines are just as crankwalk prone as stock engines or anyother? What could I do or have the engine shop due to better prevent it from happening, since that big act clutch is going to be installed?

 

[slowAWDTSi]

Originally posted by SchmeelDeal


Anyone know if Jasper engines are just as crankwalk prone as stock engines or anyother? What could I do or have the engine shop due to better prevent it from happening, since that big act clutch is going to be installed?

Not a whole lot u can do. The 1stgen 7 bolts are not as prone to crankwalk as the 2g 7bolt blocks The best thing is to keep the oil changed and watch your clutch pedal for movement. Crankwalk should be covered by the Jasper warranty just as long as you have all schedualed maintinence.
Dru
The problem with your rebuild was probably oversized rod bearings with an unground crank. That happened to my friend with a forged bottom end ,, it ate 2 of his eagle rods doh!

 

[BUCK]

Originally posted by SchmeelDeal
Rebuild shop said they took the oil pan off and found that the bearings for the balance shaft were shot and it caused the crank to dig in the case. .

What the hell kinda rebuild involves leaving balance Shafts in?:thumbdown

 

[slowAWDTSi]

Originally posted by BUCK
What the hell kinda rebuild involves leaving balance Shafts in?:thumbdown

A stock daily driven one
Duh

dru

 

[supergoat]

Originally posted by slowAWDTSi
If you get one you cant put cams in them bacause of the way they grind the head .

Can you elaborate on this? Exactly how do they grind the head so that aftermarket cams can't be installed? I'm confused by this.

 

[slowAWDTSi]

Originally posted by supergoat
Can you elaborate on this? Exactly how do they grind the head so that aftermarket cams can't be installed? I'm confused by this.

This is directly how the guy put it:
They just boar the cam bearing races (the head and cam caps) like .020 over(guessing) and they spray some kind of metal coating on the cams to build the surface of them up and re grind that sprayed metal material to match the boar on the cam bearing surface. That is to ensure proper geometry for the timing belt to lign up properly.

Thats what the guy told me. I cant seem to remember what kind of meta stuff they sprayed on it but it works for them. I wont get one from them for that reason alone. I dont like half-assing somethig like that. An engineous way to do it would be to grind out the cam caps and head and put some replaceable bearings that way stock cams could fit into them. If you ever work on a Jasper motor and replace a cam for any reason you could destroy the motor
My 2 cents
Dru

 

[SchmeelDeal]

Originally posted by slowAWDTSi
The 1stgen 7 bolts are not as prone to crankwalk as the 2g 7bolt blocks

The engine is a 6-bolt, so I guess that greatly reduces the risk.

Originally posted by slowAWDTSi
The problem with your rebuild was probably oversized rod bearings with an unground crank.

Today, I asked the guy who did the machine work on the engine about this. He said the crank was polished but not machined. He also said that the rod bearings were factory spec stock and not oversized.

The thing that I am worrired about is that the big clutch is what caused it. I don't want the same thing to happen again.

 

[BUCK]

quote:
--------------------------------------------------------------------------------
Originally posted by BUCK
What the hell kinda rebuild involves leaving balance Shafts in?
--------------------------------------------------------------------------------

A stock daily driven one - Duh - dru

Dru - WTF is stock about an ACT 2600?

How about a complete ABORTION of a complete DUMBASS rebuild - kinda like the incomplete "REBUILD" of the POS in question.

DUH

 

[crankbender]

I don't think your clutch caused your problem...however if you are worried about it go to a 2100...you arn't going to have problems with it. A 2100 is great till well beyond what you are gonna get out of that engine.

 

[slowAWDTSi]

Originally posted by BUCK
quote:
--------------------------------------------------------------------------------
Originally posted by BUCK
What the hell kinda rebuild involves leaving balance Shafts in?
--------------------------------------------------------------------------------


Dru - WTF is stock about an ACT 2600?

How about a complete ABORTION of a complete DUMBASS rebuild - kinda like the incomplete "REBUILD" of the POS in question.

DUH

Ok moron i was talking about the engine itself. If you knew a thing or to about your car you would know that they are seperate
Next time dont be an a$$
Dru

 

[slowAWDTSi]

Originally posted by crankbender
I don't think your clutch caused your problem...however if you are worried about it go to a 2100...you arn't going to have problems with it. A 2100 is great till well beyond what you are gonna get out of that engine.

I agree completly. My friend has a 2600 in his stock 6bolt motor and he had no problems with anything.
Even if it possibly some how could have caused it , it would have taken a few thousand miles i would think
Dru

 

[BUCK]

Originally posted by SchmeelDeal
Rebuild shop said they took the oil pan off and found that the bearings for the balance shaft were shot and it caused the crank to dig in the case. So they are getting me a jasper engine at no charge.

Originally posted by BUCK - What the hell kinda "rebuild" involves leaving balance shafts in?

 

[slowAWDTSi]

In other words the shop didnt even take the balance shafts out and replace the bearings at all? Well in that case BUCK i somewhat see where you are coming from. I thaught you were refering to the balance shafts as in keeping them in the motor rather than puttign an eliminator kit in.
To all that I have offended: Tuff sheet
Dru

 

[SchmeelDeal]

The balance shaft and related parts were replaced with OEM parts from Mitsubishi. The timing belt tensioner was actually installed by Mitsubishi, as well as the timing being set.

 

[RoasT BeeF]

Originally posted by crankbender
I don't think your clutch caused your problem...however if you are worried about it go to a 2100...you arn't going to have problems with it. A 2100 is great till well beyond what you are gonna get out of that engine.

2100 on an AWD? Come on man....

 

[SchmeelDeal]

Add me to the 6-bolt crankwalk list. Yep, it was real bad. Rebuild shop ended up getting me a jasper engine, which appears to have power out the ass for being stock. Although I am having A LOT or other problems now with the car, they are unrelated to this thread.

Guess the problem has been resolved, bad crankwalk = short block replacement

This thread can be closed.

 

[x camaro owner]

don;t think just because it was rebuilt it is all good. one time i replaced a motor with a long block. and after i was done with the install i started it up only to find out the motor had a rod knock. ya i was really pissed i had to redo that job the engine shop immediately sent out a new motor and then every thing was good after i put that long block in.

it made that customer a little angry that it was going to take another day to get their car back.

so moral of the story engine rebuilders aren't always perfect either, after all they are human to.