SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13D

                    Under the Securities Exchange Act of 1934

                           Allis-Chalmers Energy Inc.
                                (NAME OF ISSUER)

                     Common Stock, par value $0.01 per share
                         (TITLE OF CLASS OF SECURITIES)

                                    019645407
                                 (CUSIP NUMBER)


                            Joseph P. Bartlett, Esq.
             Greenberg Glusker Fields Claman Machtinger & Kinsella LLP
                      1900 Avenue of the Stars, 21st Floor
                         Los Angeles, California 90067
                                (310) 553-3610
                 (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON
                AUTHORIZED TO RECEIVE NOTICES AND COMMUNICATIONS)


                                 August 24, 2005
                      (DATE OF EVENT WHICH REQUIRES FILING
                               OF THIS STATEMENT)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition which is the subject of this Schedule 13D, and is filing this
schedule because of ss.ss. 240. 13d-1(e), 240.13d-1(f) or 240.13d-1(g), check
the following box [ ].

NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 240.13d-7 for other
parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).





CUSIP No. 019645407
Page 2

                                TABLE OF CONTENTS


ITEM 1. SECURITY AND ISSUER SECURITIES ACQUIRED.
ITEM 2. IDENTITY AND BACKGROUND.
ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.
ITEM 4. PURPOSE OF TRANSACTION.
ITEM 5. INTEREST IN SECURITIES OF THE ISSUER.
ITEM 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS
          WITH RESPECT TO SECURITIES OF THE ISSUER.
ITEM 7. MATERIAL TO BE FILED AS EXHIBITS.
SIGNATURE
Exhibit 7.1
Exhibit 7.2
Exhibit 7.3

--------------------------------------------------------------------------------

1. Name of Reporting Person.
     I.R.S. Identification Nos. of above persons (entities only).

     Munawar H. Hidayatallah
--------------------------------------------------------------------------------
2.   Check the Appropriate Box if a Member of a Group (See Instructions) (a) [_]
     (b) [X]
--------------------------------------------------------------------------------
3.   SEC Use Only

--------------------------------------------------------------------------------
4.   Source of Funds (See Instructions) 
     PF
--------------------------------------------------------------------------------
5.   Check If Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d)
     or 2(e) [_]
--------------------------------------------------------------------------------
6.   Citizenship or Place of Organization
     United States
--------------------------------------------------------------------------------

               7.   Sole Voting Power
 NUMBER OF          1,311,667
   SHARES      -----------------------------------------------------------------
BENEFICIALLY   8.   Shared Voting Power
 OWNED BY           0
    EACH       -----------------------------------------------------------------
  REPORTING    9.   Sole Dispositive Power
   PERSON           1,311,667
    WITH       -----------------------------------------------------------------
               10.  Shared Dispositive Power
                    0

--------------------------------------------------------------------------------
11.  Aggregate Amount Beneficially Owned by Each Reporting Person

      1,311,667
--------------------------------------------------------------------------------
12.  Check Box If the Aggregate Amount in Row (11) Excludes Certain Shares (See
     Instructions) [_]
--------------------------------------------------------------------------------
13. Percent of Class Represented by Amount in Row (11)

     8.3%
--------------------------------------------------------------------------------
14.  Type of Reporting Person (See Instructions)

     IN
--------------------------------------------------------------------------------





CUSIP No. 019645407
Page 3

Munawar H. Hidayatallah ("Mr. Hidayatallah") previously filed a statement on
Schedule 13D jointly with Saeed M. Sheikh to report their ownership of equity
securities to which this statement on Schedule 13D relates because, as a party
to the stockholders agreement dated as of April 2, 2004 (the "Stockholders
Agreement") with Donald Engel, Christopher Engel, the Engel Investors Defined
Benefit Plan, Leonard Toboroff, RER Corp., a Michigan corporation wholly-owned
by Robert Nederlander, Energy Spectrum Partners LP, Jens H. Mortensen and Saeed
M. Sheikh, Mr. Hidayatallah could have been deemed to be part of a group with
Mr. Sheikh. While Mr. Hidayatallah continues to disclaim that he has ever formed
or been part of a group among the other parties to the Stockholders Agreement,
he is filing this statement on Schedule 13D because the Stockholders Agreement
was terminated by the parties on August 24, 2005. All share amounts have been
restated to give effect to a one-to-five reverse stock split effective June 10,
2004.


ITEM 1. SECURITY AND ISSUER SECURITIES ACQUIRED.

Security: Common Stock of Allis-Chalmers Energy Inc. ("Common Stock").

Issuer: Allis-Chalmers Energy Inc. ("Issuer"), 5075 Westheimer, Suite 890,
Houston, TX 77056.


ITEM 2. IDENTITY AND BACKGROUND.

Pursuant to Rule 13d-1(a) of Regulation 13D-G of the General Rules and
Regulations under the Securities Exchange Act of 1934, as amended (the "Act"),
this Schedule 13D statement is hereby filed by Munawar H. Hidayatallah (the
"Reporting Person"), who is a U.S. citizen.





CUSIP No. 019645407
Page 4


Mr. Hidayatallah's address is 5075 Westheimer, Suite 890, Houston, Texas 77056.

Mr. Hidayatallah is the chief executive officer and chairman of the board of the
Issuer.

The Reporting Person disclaims beneficial ownership of the securities reported
as beneficially owned by the Reporting Person herein other than the securities
owned directly by such person.

The Reporting Person has not, during the last five years, (i) been convicted in
a criminal proceeding (excluding traffic violations or similar misdemeanors) or
(ii) been a party to a civil proceeding of a judicial or administrative body of
competent jurisdiction and as a result of such proceeding was or is subject to a
judgment, decree or final order enjoining future violations of, or prohibiting
activities subject to, federal or state securities laws or finding any violation
of such laws.


ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

This Schedule 13D is being filed to report the termination of the Stockholders 
Agreement.  See Item 4.


ITEM 4. PURPOSE OF TRANSACTION.

On May 9, 2001, OilQuip Rentals, Inc., a Delaware Corporation ("OilQuip"), was
merged with and into Allis-Chalmers Acquisitions Co., a Delaware Corporation,
and a wholly-owned subsidiary of the Issuer (the "Merger"). The purpose of the
Merger was to combine the operations of OilQuip and the Issuer, and to provide
services for the exploration and production of natural gas. Mr. Hidayatallah was
issued 875,000 shares of Common Stock in the Merger.

On April 2, 2004, (a) in exchange for an investment of $2 million, the Issuer
issued 620,000 shares of Common Stock, and warrants to purchase 800,000 shares
of Common Stock at an exercise price of $2.50 per share expiring on April 1,
2006, to an investor group consisting of Donald Engel, Christopher Engel, the
Engel Investors Defined Benefit Plan, Leonard Toboroff and RER Corp., a Michigan
corporation wholly-owned by Robert E. Nederlander (the "Investor Group"). In
connection therewith, the Investor Group, Mr. Hidayatallah, Saeed M. Sheikh,
Jens H. Mortensen, Energy Spectrum Partners LP, the Issuer and others entered
into a stockholders agreement (the "Stockholders Agreement"), pursuant to which
the parties agreed to vote for the election to the board of directors of the
Issuer three persons nominated by Energy Spectrum, two persons nominated by the
Investor Group and one person nominated by Messrs. Hidayatallah, Mortensen and
Sheikh. The parties and the Issuer also agreed that in the event the Issuer has
not completed a public offering of its shares prior to September 30, 2005, then,
at the request of Energy Spectrum, the Issuer will retain an investment banking
firm to identify candidates for a transaction involving the sale of the Issuer
or its assets. In addition, the Issuer, Energy Spectrum, the Investor Group and
Messrs. Sheikh, Hidayatallah and Mortensen entered into a registration rights
agreement with the Issuer and other parties named therein dated April 2, 2004
(the "Registration Rights Agreement"), pursuant to which the parties were
granted certain registration rights with respect to the Common Stock owned or to
be owned by such parties.





CUSIP No. 019645407
Page 5

In June 2005, the parties entered into a First Amendment to Stockholders
Agreement dated April 4, 2004, which provided that (a) unless and until Energy
Spectrum notified the Issuer and the other parties to the Stockholders Agreement
that it elected to nominate all three directors it was entitled to nominate,
Energy Spectrum would have the right to designate one nominee to be elected as a
member of the Issuer's board of directors and the other parties would not be
entitled to nominate any directors, and (b) the Stockholders Agreement would
terminate upon the completion of an offering if all shares owned by Energy
Spectrum were sold. On August 24, 2005, Energy Spectrum sold all of its shares
and the Stockholders Agreement was terminated.

The Reporting Person acquired the shares of Common Stock as an investment.

The Reporting Person reserves the right to (i) dispose of all or part of his
investment in the Common Stock at any time, (ii) acquire additional equity
securities of the Issuer or its affiliates in the open market, in private
transactions or otherwise, (iii) propose a merger or other business combination
with the Issuer or its affiliates, or (iv) take any other action with respect to
the Issuer. Any such purchases will depend upon the market prices for the shares
of Common Stock, the number of shares which may become available for purchase at
prices which he regards as attractive and various other factors which he may
determine to be relevant.

Except as set forth in this Item 4, the Reporting Person does not have any
current plans or proposals which relate to or would result in (a) an
extraordinary corporate transaction, such as a merger, reorganization or
liquidation of the Issuer or any of its subsidiaries; (b) the sale or transfer
of a material amount of assets of the Issuer or any of its subsidiaries; (c) any
change in the Issuer's present board of directors or management; (d) any
material change in the present capitalization or dividend policy of the Issuer;
(e) any other major change in the Issuer's business or corporate structure; (f)
any change in the Issuer's charter or by-laws that might impede the acquisition
or control of the Issuer by any person; (g) the delisting of a class of the
Issuer's securities on a national securities exchange; (h) the termination of
registration pursuant to Section 12(g)(4) of the Securities Exchange Act of
1934, as amended, of a class of the Issuer's equity securities; or (i) any
action similar to any of those enumerated above. However, as indicated above,
the Reporting Person intends continuously to review his investment in the
Issuer. Depending upon the results of such continuing review and other factors,
the Reporting Persons reserves the right to propose, take or seek to cause the
Issuer to take, one or more of the transactions described in this paragraph.


ITEM 5. INTEREST IN SECURITIES OF THE ISSUER.

a) Mr. Hidayatallah is the beneficial owner of 1,311,667 shares of the Common
Stock, which constitutes approximately 8.3% of the shares of the Common Stock
outstanding on the date hereof, according to information provided by the Issuer.
The number of shares of Common Stock beneficially owned by Mr. Hidayatallah
includes: (i) 875,000 shares owned by the Hidayatallah Family Trust and (ii)
466,667 shares that may be issued within 60 days upon the exercise of options
granted under the Issuer's 2003 Incentive Stock Plan.

b) Mr. Hidayatallah has sole voting power and sole power of disposition with
respect to all shares of Common Stock beneficially owned by him.

c) Mr. Hidayatallah has not effected any transactions with respect to the Common
Stock within the past 60 days.





CUSIP No. 019645407
Page 6


d) Not applicable.

e) Not applicable.


ITEM 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO
SECURITIES OF THE ISSUER.

To the best knowledge of Mr. Hidayatallah, there are currently no contracts,
arrangements, understandings or relationships (legal or otherwise) between Mr.
Hidayatallah and any other person or with respect to any securities of the
Issuer, including, but not limited to, transfer or voting of any of the
securities of the Issuer, finder's fees, joint ventures, loan or option
arrangements, puts or calls, guarantees of profits, division of profits or loss,
the giving or withholding of proxies, or a pledge or contingency the occurrence
of which would give another person voting power over the securities of the
Issuer.


ITEM 7. MATERIAL TO BE FILED AS EXHIBITS.

Exhibit 7.1: Stockholders Agreement dated April 2, 2004, by and among the
Issuer, Mr. Hidayatallah and the other persons signatory thereto (1).

Exhibit 7.2: Registration Rights Agreement dated April 2, 2004, by and among the
Issuer and the other persons signatory thereto (1).

Exhibit 7.3: First Amendment to Stockholders Agreement dated April 2, 2004, by
and among the Issuer and the other persons signatory thereto, dated as of July
29, 2005.

(1) Filed as an exhibit to Schedule 13D filed by Mr. Hidayatallah on April 12,
2004.


                                   SIGNATURE

After reasonable inquiry and to the best of the knowledge and belief of the
undersigned, the undersigned certifies that the information set forth in this
statement is true, complete and correct.

Pursuant to Rule 13d-1(k)(l)(iii) of Regulation 13D-G of the General Rules and
Regulations of the Securities and Exchange Commission under the Securities
Exchange Act of 1934, as amended, the undersigned agrees that the attached
statement is filed on behalf of him in the capacities set forth below.



       DATED: August 25, 2005                     /s/ Munawar H. Hidayatallah
                                                  ----------------------------
                                                  MUNAWAR H. HIDAYATALLAH