Bad harmonic balancer keyway
Thread Starter
Senior Member
Posts like a Northstar
Joined: Apr 2006
Posts: 549
Likes: 0
From: Dimondale, MI

Howdy. Pretend its a '95 SSEi...
I was having trouble last season when I parked my car. It seemed like something let go inside the trans, and it felt like the engine was ALWAYS under a load. Acceleration was awful, too slow to drive on the streets. I could slowly build up RPM fine. In some older threads on this, we figured that something died in the trans after trying everything we could with the engine.
However, upon pulling the motor/tranny out, we found that the harmonic balancer has a lot of play in the keyway. I can't remember at the moment, but maybe an inch from the outside :( . Could this throw off the crankshaft position sensor and cause a condition like the one I've had? The engine feels to be on a load in drive, reverse, park, neutral, etc and when accelerating it feels like its having to tow a 8k pound trailer.
Could it really have been the harmonic balancer keyway?
I was having trouble last season when I parked my car. It seemed like something let go inside the trans, and it felt like the engine was ALWAYS under a load. Acceleration was awful, too slow to drive on the streets. I could slowly build up RPM fine. In some older threads on this, we figured that something died in the trans after trying everything we could with the engine.
However, upon pulling the motor/tranny out, we found that the harmonic balancer has a lot of play in the keyway. I can't remember at the moment, but maybe an inch from the outside :( . Could this throw off the crankshaft position sensor and cause a condition like the one I've had? The engine feels to be on a load in drive, reverse, park, neutral, etc and when accelerating it feels like its having to tow a 8k pound trailer.
Could it really have been the harmonic balancer keyway?
F14crazy, the earlier cranks like yours are notorious for HB'* simply slipping off after bolt removal without the need for a puller.
So you put a HB from a 95 on your old crankshaft with that reputation (not designed for the bottom end you put it on), and I think what you got was what was to be expected. These are not swappable parts.
Our advice from the beginning was to not do this top swap. This is one of the many issues involved.
I'd suggest at this point that you swap in the entire L67 drivetrain, wiring harness, and PCM from the donor vehicle of your choice. Even if the keyway hadn't beat itself to death, you would have suffered from either bottom end failure or trans issues in a very short period of time.
So you put a HB from a 95 on your old crankshaft with that reputation (not designed for the bottom end you put it on), and I think what you got was what was to be expected. These are not swappable parts.
Our advice from the beginning was to not do this top swap. This is one of the many issues involved.
I'd suggest at this point that you swap in the entire L67 drivetrain, wiring harness, and PCM from the donor vehicle of your choice. Even if the keyway hadn't beat itself to death, you would have suffered from either bottom end failure or trans issues in a very short period of time.
Thread Starter
Senior Member
Posts like a Northstar
Joined: Apr 2006
Posts: 549
Likes: 0
From: Dimondale, MI

At any rate, the motor seems to be okay. I figure I'll be set with a new harmonic balancer. I didn't drive it long at all in this condition. To be exact, it feels like the car has to tow like 8k pounds.
Willren: I don't think you've ever said anything positive about my engine project. And...
-I just checked the Reatta FSM. NO puller is necessary to remove the balancer. It really does just fall off. It'* made that way. How is this "notorious"? I've pulled off a number of stock balancers, and they fall off. So what?

-I will personally pay you a great deal of money if you can get an L67 PCM to perfectly interface with this.
-My bottom end is perfectly fine. 20k miles with the swap without internal engine failure nor transmission failure.
Willren: I don't think you've ever said anything positive about my engine project. And...
-I just checked the Reatta FSM. NO puller is necessary to remove the balancer. It really does just fall off. It'* made that way. How is this "notorious"? I've pulled off a number of stock balancers, and they fall off. So what?

-I will personally pay you a great deal of money if you can get an L67 PCM to perfectly interface with this.
-My bottom end is perfectly fine. 20k miles with the swap without internal engine failure nor transmission failure.
Hi guys.
Before anyone gets too carried away....
Is it possible that the crankshaft and balancer were changed between LN3 and L27?
In the Australian (where I am from) versions of the LN3 (two piece rope rear main seal, coil pack, for ID), the balancer is a slip fit. On the L27(one piece rear main seal, individual coils) it was made an interference fit. Could this be the problem?
(I have been looking at using the US series 1 */C on my L27 so F14CRAZY, your 'How to" posts have been awesome. As all our 3800 V6'* are RWD, I am still not sure about firewall clearance though. It'* definitely an issue with the S11 L67 and our local versions use a different M90 */C housing. I was hoping that the M62 on the S1 may be shorter, not to mention that the S11 parts aren't a straight swap on an L27).
PS: Sorry to drag up a relatively old post.
Before anyone gets too carried away....
Is it possible that the crankshaft and balancer were changed between LN3 and L27?
In the Australian (where I am from) versions of the LN3 (two piece rope rear main seal, coil pack, for ID), the balancer is a slip fit. On the L27(one piece rear main seal, individual coils) it was made an interference fit. Could this be the problem?
(I have been looking at using the US series 1 */C on my L27 so F14CRAZY, your 'How to" posts have been awesome. As all our 3800 V6'* are RWD, I am still not sure about firewall clearance though. It'* definitely an issue with the S11 L67 and our local versions use a different M90 */C housing. I was hoping that the M62 on the S1 may be shorter, not to mention that the S11 parts aren't a straight swap on an L27).
PS: Sorry to drag up a relatively old post.
Thread
Thread Starter
Forum
Replies
Last Post






