Advice from Mechanical PE Examinees

“Been There!”—Advice from Mechanical PE Examinees

This page is a compilation of comments contributed by engineers who have recently taken the Mechanical PE exam. Some of the advice may seem contradictory—sometimes engineers disagree. Nobody received compensation for mentioning any product.

As you read this advice, keep in mind that the exams change from administration to administration. Subjects that are emphasized on one exam may not show up at all on the next exam.

If you would like to contribute to this compilation, email us with the subject line “Mechanical PE Exam Advice.” In the body of your email, please note your exam section and exam date.

General Mechanical PE Exam Advice

Advice for the HVAC and Refrigeration Section

Advice for the Machine Design Section

Advice for the Thermal and Fluid Systems Section

General Mechanical PE Exam Advice

Don’t leave any blanks on the answer sheet. If you really don’t know how to solve the problem, just guess. By guessing, I don’t mean filling out the blank with you eyes closed. Use your best engineering sense, first eliminate the impossible, then pick out the most probable one.

If you bring a mountain of reference material, I hope you are lightning fast because the amount of time you can spend on each problem averages five or six minutes. I checked my time every 30 minutes and was disturbed to learn my average time per problem was eight minutes. My best advice is to practice working problems quickly and do not depend on a lot of reference material. In the last 15 minutes, go over the unsolved problems and perform a “best guess” method. This, I think, will get you more points than working the few problems you have time for since wrong solutions do not count against you.

Take the advice given in Mechanical Engineering Reference Manual (MERM) and be a generalist. Be as prepared as you can (reasonably) for any possible subject mentioned in the exam specifications. Don’t get too hung up on what happened last time, because the exams change GREATLY in focus from one time to the next.

A cheapo $15 solar powered scientific calculator was fine for the exam. I did not miss my HP48GX at all. Don’t worry about the calculator part. DO study with the calculator you intend to use. Bring an extra calculator (the same model) but don’t take it out of the package. If you don’t use it, return it, and you’ve spent nothing.

Study the blueprint of the exam and take it seriously. Although problems will not appear in the same proportion each time (despite what NCEES suggests), any of these subjects can and will eventually appear on the exam. No single exam prep book is going to “have it all.” Face the fact that the NCEES is searching for topics outside the scope of most review books. Bring enough diverse references to cover most subjects, and become familiar with them before the exam.

If you are re-taking the exam (or reading this information), don’t necessarily concentrate on the subjects that showed up on the previous exam. In my experience (I just took my second exam), these subjects are barely mentioned on the next exam. Bottom line—you have to study everything, or else be very lucky.

Plan to spend 250–300 hours in preparation. Start 3-4 months before the exam.

Print out the MERM index from this website and bind it separately, so you can flip through it quickly without having to throw that anchor of a book back and forth!

MERM suggests that you can bring large-size Mollier charts to the exam, which I did. I was not allowed to use them because they were loose-leaf.

Don’t think you have to go through MERM from front to back. Start with, and stick with, the meaty subjects. I wasted too much time on the math and other “background” sections.

Memorize the contents of the Appendix in the back of MERM. Work as many problems on your own as possible, including the example problems—the more, the better.

Use many, many tabs to help you navigate quickly around MERM. And be sure to check what kind of tabs your state board allows—some don’t allow removable sticky tabs.

I found MERM extremely helpful, especially since I took the time to put color-coded tabs on each section. After spending a few months using those tabs, I became accustomed to them and they reduced my downtime.

If you can only take one reference to your Mechanical PE exam, let it be MERM! Without it, I would not have been able to pass the exam on my first try. Words of advice: know MERM inside-out and do TIMED practice exams. You will not regret it.

Be prepared for 40 UNRELATED problems in the morning and 40 UNRELATED problems in the afternoon. That’s 80 entirely separate scenarios you are presented with. And many of them have unnecessary information provided, which you have to weed out.

I can’t stress enough how important practice problems are. You must build speed, since you’re battling the clock more than the complexity of the exam.

Sit down and take a full, 8-hour practice exam, and time yourself. You can’t imagine how fast you must work until you have done this. It was the best preparation I did for the exam.

You can’t imagine how critical time is on this exam until you take it. You must be able to work full-bore for eight hours. It really requires mental discipline to keep up the pace. Try a sample exam and you’ll get an idea.

Take time to read the MERM chapters, instead of just working the problems at the end of each chapter. If anything, I found it most helpful to work the example problems within each chapter, rather than the ones in the practice problems book.

If you bring codes, take time to look through them before the exam so you know where to find information. Don’t bother to bring any book you haven’t at least flipped through right before the exam.

Make sure you understand the basic theory behind any problem-solving methodology. Also, it’s critical to time yourself during practice. I could have done a much better job had I been used to working problems with a time constraint.

You’re not going to find a “plug and chug” equation for every problem. You need to understand the fundamental physics and thermodynamics for each type of problem, so you can develop a solution.

Choose your afternoon session well in advance and study for it! There’s too much detail to review—you can’t go into this exam without a focus.

Spend the first several minutes of each session reading over all 40 problems. Make a list of those you know you can get fairly easily. Make sure you have completed all of these before moving on to other problems.

Don’t get hung up on a specific problem. If you can’t work it right off, then move on. You can come back if you have time. Don’t spend more than six minutes on ANY problem your first time through.

READ THE PROBLEM. It’s easy to jump right in and start calculating, but if you miss a minor detail in the problem statement, you may not be solving the right problem.

Don’t over-engineer the problems. Many were rather basic engineering/physics problems and didn’t require any deep theoretical pondering. Solve for what NCEES wants, not necessarily what YOU think you should solve for.

Expect to see problems on obscure topics. The index in MERM is a help here. Other books, like college texts with good indexes are also helpful. Once you understand the oddball scenarios, the problems aren’t too hard to solve. It’s just trying to grasp what’s being asked that’s time-consuming.

Be prepared for trick problems. The writers use “weasel words” to confuse you about exactly what is being asked for. Read the problems slowly and carefully. Then speed up once you’ve got the right idea.

Watch for those “most nearly” problems. They can trip you up.

The problems are in completely random order. Don’t look for all the fluids problems in one place. Expect to bounce from one topic to a completely unrelated topic.

Practice working problems at random, not all one topic at a time. It’s imperative that you be able to shift gears quickly.

Time yourself on a practice exam not long far before the exam itself, and make note of what kind of mistakes you make. Many of my errors were stupid things like leaving out efficiency or reversing diameter and radius. It made me realize I needed to slow down and check my work.

Watch out for common mistakes involving unit conversion, such as using area moment of inertia instead of polar moment of inertia. The wrong answer will absolutely be one of your answer choices.

Even though MERM uses SI units, don’t waste time studying them. My exam was all the English units. Know conversions well.

Get the NCEES Sample Questions. Any source for more problems is good, and this is from the horse’s mouth.

I passed the first time largely due to my familiarity with MERM. It was my primary reference for both sessions. My review was short, intense and mainly consisted of working NCEES sample problems with the aid of MERM. The Passing Zone was worth every cent. The advisors are very responsive.

Advice for the HVAC and Refrigeration Section

MERM is great for the morning breadth session, but not so good for the HVAC depth module. Bring other references with you: all the ASHRAE code manuals, NFPA 90A, even electrical codes.

I found the practice problems in MERM to be harder than those on the exam. The problems in the NCEES Sample Questions book were very representative of the HVAC section, at least this time around.

Study refrigerant phase diagrams and know how to plot basic refrigeration systems on them. Buy a couple of old refrigeration textbooks and study basic example problems. Once you learn how to plot these processes and relate them to an equipment diagram, they’re easy.

I was surprised that the HVAC section had so many non-HVAC problems!

Be prepared for a lot of non-typical HVAC equipment configurations.

Bring Cameron Hydraulic Data to the exam. It provides “shortcut” formulas which saved time on the exam.

It’s helpful to leave one book open to a psych chart, one to steam tables, and one to air properties. This saves time during the exam.

Bring all four ASHRAE Handbooks with you—Fundamentals, HVAC Applications, HVAC Systems & Equipment, and Refrigeration. You might only use them for three or four problems, but these will be easy slam dunk answers.

Bring NFPA 90A with you—it was very useful.

My Trane Air Conditioning Manual was helpful.

I never thought there would be problems on what section of NFPA you would need to find specific design-governing elements. Wish I’d had the code books or at least an index.

Don’t bring loose psychrometric charts. The exam instructions say you cannot write on anything except the exam.

I needed to be more familiar with energy recovery wheels. I lost valuable time on these problems.

Study turbines! I’ve worked in A/C and heating and hadn’t done any steam turbine work since school.

I needed familiarity with the thermal properties of poultry, beef, etc. It’s not in MERM (maybe it shouldn’t be).

Be familiar with absorption chillers and ammonia refrigeration plants. I knew these could appear on the exam but I didn’t study either, to my regret.

Unconventional units are used a lot, so expect to spend time doing conversion. Also expect problems with atypical constraints such as high altitude, extremely low humidity, etc.

You wouldn’t believe how many fan and pump law problems showed up on the exam. Know where to find the formulas, then plug and chug!

Psychrometrics, psychrometrics, psychrometrics!

Advice for the Machine Design Section

The machine design section could be called the “Shigley and Mischke Exam.” Essentially every problem in the afternoon exam was covered in Shigley and Mischke. Buy this reference and know it cold.

Machinery’s Handbook came in handy for densities, moduli, strength values, etc.

Know and understand column buckling.

Don’t expect the exam to adhere to the percentages in the NCEES exam specs. Study all the topic areas listed.

MERM alone is not enough for this afternoon exam. Bring other resources that you can use comfortably.

MERM, Shigley, and the Machinery’s Handbook got me through.

I only needed a couple of references for the exam: MERM, Shigley, Cameron Hydraulic Data (or Crane No. 410 would do).

I passed first time largely due to my familiarity with MERM. Mechanical Engineering Design by Shigley and Mischke was my other primary reference. I also felt Marks’ and Machinery’s Handbook were essential.

MERM was great for breadth. You must take your other favorite machine design book(s)—Juvinall’s Fundamentals of Machine Component Design did it for me. Don’t waste your time with SI Units. The exam (to my dismay, even when anticipated to an extent) was COMPLETELY in English units.

There were more difficult vibrations problems on the exam than I expected.

Study thermodynamics and HVAC even if you do not plan on working those afternoon sessions, as there were still a lot of problems on those topics.

Sadly, I only saw three machine design problems in the morning section of the exam. Study those other fields well. For the afternoon portion, study dynamics and vibrations.

Look out for project management problems.

I didn’t expect the engineering ethics problem.

There were way more psychrometric problems in the morning exam this time—what a killer!

Do not discount the thermo/fluids and HVAC portion of the morning exam in your studies. There were a LOT of these problems in the morning portion.

Study thermo and heat transfer extensively.

The sample problems from NCEES for machine design did not prepare me for the difficulty of the exam, which is much harder and more in-depth.

Expect to see problems on combustion, air:fuel ration, and out-of-balance rotating drums.

Welding problems were in abundance. Nobody I knew was prepared for them.

I was surprised at the number of engineering economics and the spring design problems.

No engineering economics problems this time at all.

Bring your own steam tables rather than relying on the partial sets in books.

I didn’t expect the amount of emphasis there was on helical springs—many problems here.

Get a chart of standard electrical symbols—it will be helpful for the electrical problems.

Advice for the Thermal and Fluid Systems Section

"I bought from Mr. Lindeburg many resources already to further my career and mellow as a real engineer. I tell you, you are not a real mechanical engineer if you have not read the MERM and done all his practice problems of his books. I am humbled to say that you could probably pass the mechanical PE exam without studying his entire volumes, but you are not a real engineer if you have not really sat down to stroke a pencil/pen doing his real problems. Exam problems are much easier, so if one has worked all his problems just like he says one should be okay...all I can say is that I passed pe mech exam with thermal/fluids systems in the afternoon and yes, I am keeping all Mr. Lindeburg's books that I have bought." -Vicente Bonilla, Houston TX

Base your study ENTIRELY on the MERM. It covered, in my case, at least 80–90% of the exam. Don’t take too many books with you. Including MERM, I only took six books with me and I only used one of them: Marks’ Standard Handbook for Mechanical Engineers which my uncle also used when he took his PE exam 28 years ago.

I expected to see some unit conversion, but the amount you end up having to do is really excessive.

You’ll need to know theory very well; otherwise you will waste a lot of time. Don’t just practice cookbook problem solving. Read and study your basic theory, in MERM or your college books.

Where you need to go to do well on the afternoon module, MERM can’t take you. You’ll need to brush up with college texts and other, more heavy-duty references.

I expected power cycle problems on this exam but didn’t expect to see so many on the Brayton gas turbine cycle (and its reverse). Seemed like they made up half the afternoon session!

Don’t think that the Thermo section is going to be all about Thermo. The other topics—HVAC, machine design—are represented to a surprisingly healthy extent.

I should have studied much more broadly than I did. There were a lot of difficult HVAC problems.

There are too many HVAC problems in the thermal/fluids exam! I object!

What was up with all the problems on combustion of fuels and hydrocarbons? I thought I was taking the ChemE exam by mistake!

The number of combustion problems and engineering economics problems really surprised me. Of course, the next exam will probably be different.

Study Rankine and Brayton cycles and get comfortable with your psych chart—you’ll need it.

You need to know it all for the afternoon section: fluid, thermal, combustion, ash analysis, gas turbine and compression, HVAC, refrigeration, and mechanics.

I can honestly report that MERM was useful for 95% of the problems on this exam. For the other 5%, I used a college HVAC text.

You must, must, must have complete steam and gas tables. The time you can waste trying to interpolate is agonizing. And make sure your tables go into higher temperature and pressure ranges than what’s in MERM.

Know vapor power cycles and equipment cold. Expect lots of turbine problems too, which are easy if you get the basics down.

There were a surprising number of problems on ASME and ANSI codes and standards.

I was surprised by the references to the ASME codes and standards on the exam. I didn’t realize this was going to show up (although I saw it afterward on the exam specs).

Be prepared for thermodynamic cycles using a substance other than water or air as the working fluid. It seemed like nearly all problems used a non-standard working fluid.

I didn’t expect the quantity of psychrometrics problems that appeared in both the morning and afternoon sections of the exam.

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