2.3 liter engine overhaul due to abuse

[cclngthr]

In the shop, we have a 2004 MZ3 that came in with a intermittent knock. Car looks as it were beat on and this proves it:

This is the #2 cylinder rod and crank bearing. Crank was scarred enough to require a complete regrind and all new bearings for both rods and main units. The one in the picture is actually torn at the one edge of the lower bearing. Also had to rering the motor as well.

Costing the customer about $3800 to redo the motor.

 

[tigermack]

It'd be cheaper to buy a new motor...

 

[MAZDA_SPEED]

yup

 

[cclngthr]

The new motor is $4700-$5000, not including installation. Doing this is actually cheaper. $3800 includes labor to R&R the motor.

 

[Yuko]

The new motor is $4700-$5000, not including installation. Doing this is actually cheaper. $3800 includes labor to R&R the motor.

Im sure you can locate one cheaper than that, and if you dog your car why not build it while your in there? I can has Turbo plz?

 

[cclngthr]

Im sure you can locate one cheaper than that, and if you dog your car why not build it while your in there? I can has Turbo plz?

Not my car. It is a customers car. Customer bought it with a bad motor for cheap and we are freshening up the motor and revising what we think is a bad design. It is a 2004 with an automatic transmission. In addition to this, we have state emission inspections and a turbo on a N/A designed car would fail instantly.

The customer told us who he bought it from, and when we checked, I found where the old owner was charged with street racing several times where it was shown that the car had been rev'd up for a long period of time and receipts show that maintanance was not done to specifications.

 

[chromal]

I wonder if this sort of wear and tear is specifically caused by lots of redlineing the engine, a lack of timely oil changes, or both?

 

[cclngthr]

I wonder if this sort of wear and tear is specifically caused by lots of redlineing the engine, a lack of timely oil changes, or both?

I am guessing, from the look of things, and what Bud, who did most of the machining said, a combination of both redlining the motor plus using the wrong oil in the motor. The car looks like it has been beat on hard, and from the oil not being the proper viscosity and not being changed often enough.

These engines REQUIRE 5w20 oil due to the small oil journals and Bud thought the residual oil seemed thicker than 5w20 oil. We did not see any sludge buildup, but know that sludge buildup is an issue with these engines.

The bearing in the picture is one of the crank bearings that had spun. The top half had cut into the bottom half as it had spun around. Normally, the bearing pieces are the same diameter around and this one wasn't. We had to add a lot of metal to the crank and grind that new metal down so the crank would be within tolerance. The rod you see could not be saved. It had gotten too hot around the crank section.

 

[Yuko]

I am guessing, from the look of things, and what Bud, who did most of the machining said, a combination of both redlining the motor plus using the wrong oil in the motor. The car looks like it has been beat on hard, and from the oil not being the proper viscosity and not being changed often enough.

These engines REQUIRE 5w20 oil due to the small oil journals and Bud thought the residual oil seemed thicker than 5w20 oil. We did not see any sludge buildup, but know that sludge buildup is an issue with these engines.

The bearing in the picture is one of the crank bearings that had spun. The top half had cut into the bottom half as it had spun around. Normally, the bearing pieces are the same diameter around and this one wasn't. We had to add a lot of metal to the crank and grind that new metal down so the crank would be within tolerance. The rod you see could not be saved. It had gotten too hot around the crank section.

Damn well good luck, that sounds like a bad day.

 

[cclngthr]

Damn well good luck, that sounds like a bad day.

We have the engine back together and did a break-in run on the engine dyno. Runs good. noticed it is a bit on the rich side and we are going to see if we can lean it out somewhat. Our cost for the engine redo is $1275.96.

Next thing on the list is fixing the rear hatch door, rear bumper and front bumper. We are not going to make a lot of money on this thing because the customer expects us to only spend so much money.