Second quarter were up 3% versus a year ago and up 7% sequentially from the first quarter.
We incurred $14.8 million in restructuring expense and expect annualized savings of approximately $8 million once the restructuring activities are completed over the next 12 months.
Excluding the impact from our restructuring actions, gross margin was up 30 basis points from the prior year as lower raw material costs, including benefits from our procurement initiatives more than offset the increasing pressure from an unavoidable mix of sales.
With continuing momentum, we expect full year sales to be up 5% to 8% over 2020, including favorability from FX of about 3%.
We're also projecting adjusted operating margin to increase 60 to 100 basis points, driven largely by gross margin strength.
We had solid cash conversion during second quarter, and our balance sheet is in good shape with our net debt to EBITDA ratio sitting at 0.7 times.
Total second quarter sales were up 2.6% from the prior year or 0.2% in local currency.
Total Engine segment sales rose over 6%, and Industrial was down 4%.
Within Off-Road, our second quarter sales in China were up about 70%.
On-Road sales were down about 1% in the quarter, which is our best year-over-year result since fiscal 2019, signaling to us that the second quarter was the cyclical trough in this business.
Second quarter sales of Aftermarket were up over 7% year-over-year, and they were also up 4% sequentially from the first quarter, which is atypical and serves as another indicator that market conditions are improving.
In China, second quarter sales of Engine Aftermarket were up over 30%.
Overall, PowerCore sales increased about 9% in second quarter with strong growth in both first-fit and replacement parts.
Aerospace and Defense, which represents about 3% of our business, faced another tough quarter due primarily to the ongoing pandemic-related weakness in commercial aerospace while sales for helicopters continue to perform well.
Second quarter sales were down about 4%, including a 3% benefit from currency.
We launched LifeTec five years ago with fewer than 10 salespeople, and we're on track to be over 100 by the end of this fiscal year.
Sales of Gas Turbine Systems, or GTS, were down 3.5% in second quarter as large project deliveries, though a smaller part of our business, were less than the prior year.
Sales were up 2.6% from the prior year, and adjusted operating income grew 7.6%.
The projects we initiated in the second quarter should generate annual savings of about $8 million once fully implemented with about $1 million realized in this fiscal year.
These actions drove a second quarter charge of $14.8 million and resulted in an operating margin headwind of about 220 basis points and an earnings per share impact of $0.08.
As I said earlier, adjusted operating profit, which excludes restructuring charges, was up 7.6% from the prior year.
That translates to an adjusted operating margin of 13.4%, which is 60 basis points up from the prior year.
Second quarter adjusted gross margin grew 30 basis points to 34%, accounting for half the operating margin increase.
As a rate of sales, second quarter adjusted operating expense was 30 basis points favorable versus the prior year, continued benefits from lower discretionary expenses due in part to the pandemic-related restrictions were partially offset by higher incentive compensation.
If you exclude restructuring charges, the second quarter Industrial profit rate was down about 50 basis points from the prior year, reflecting incremental investments in businesses like Process Filtration and Venting Solutions.
We invested about $12 million in the second quarter, which is down more than 70% from the prior year.
We returned more than $57 million to shareholders through dividends and share repurchase, bringing our year-to-date total to almost $100 million.
We have increased our dividend each calendar year for the past 25 years, making us part of the elite group included in the S&P High Yield Dividend Aristocrat index.
Our position on the dividend is the same as it was 65 years ago when we began paying it every quarter.
With this in mind, we expect sales this year to return to a pattern that is generally in line with our typical seasonality, where about 52% of our full year revenue occurs in the back half.
Therefore, we expect full year sales will increase between 5% to 8%, which includes the benefit from currency translation of about 3%.
In the Engine segment, full year sales are projected to increase between 8% and 12% with our first-fit business comprising a bigger piece of the recovery story in the back half.
We expect full year Off-Road sales to increase in the low 20% range with building strength in commodity prices driving an acceleration in equipment production in agriculture and other select markets.
In the Industrial segment, full year sales are projected to be between a 2% decline and a 2% increase as recovery in the capital investment environment is still emerging.
At a company level, we are expecting an adjusted operating margin to increase to within a range of 13.8% and 14.2% compared to 13.2% in 2020.
This implies a sequential step up in our operating margin to 14.4% for the back half of the year and aligns with our commitment to increasing profitability on increasing sales.
Additionally, we expect to maintain a disciplined approach to our operating expenses and deliver further leverage in the back half of the year despite an expected full year headwind of approximately $20 million from increased incentive compensation, about 2/3 of which is in the back half of the fiscal year.
For our other operating metrics, we expect interest expense of about $13 million, other income of $2 million to $4 million, and a tax rate between 24% and 25%.
Taking the midpoint of our sales and capex guidance for 2021 would put it at just over 2% of sales.
We expect to repurchase 1% to 2% of our outstanding shares.
Finally, our cash conversion was very good in the first half, and we continue to expect to exceed 100%, reflecting strong first half conversion and anticipated increases in working capital later in the fiscal year.
It's a straightforward plan, and it has served us well for 106 years, giving me confidence we are in an excellent position to deliver a strong finish to fiscal 2021.

Summary:
With continuing momentum, we expect full year sales to be up 5% to 8% over 2020, including favorability from FX of about 3%.
These actions drove a second quarter charge of $14.8 million and resulted in an operating margin headwind of about 220 basis points and an earnings per share impact of $0.08.
Therefore, we expect full year sales will increase between 5% to 8%, which includes the benefit from currency translation of about 3%.