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ZShack Engine Warranty

Do You Offer a Warranty On Your Engines?

You have to keep in mind; whether a warranty is 1 year or 5 years long, it makes no difference. An engine is a machine. If something is machined wrong or isn't correct, it is going to be that way right from the beginning and will show up IMMEDIATELY. A bad clearance (too tight or too loose), a bad valve seat, loose guides, a poor fit and finish of a bearing journal or cylinder wall, will show up the minute you start-up the engine with smoke, knocking, bad oil pressure, extremely high oil temperatures, water in the oil, oil in the water, etc., and a short term catastrophic failure will happen. It won't run great for 2 or 3 months and then "decide" to start showing bad symptoms if something isn't right from the get-go, so the "length" of a warranty after a given amount of time really means nothing, and it is more of a sales gimmick to get you to THINK an engine with the longer warranty is better. Nothing could be farther from the truth!

If an engine runs well for the first couple of hours, it should run well for a long, long time, as long as it isn't abused, neglected or something stupid is done to it by the new owner, and/or as long as the components chosen to go IN it are strong enough to meet the tasks that engine is going to be used for.

No manufacturer on the planet (Ford, GM, Chrysler, Lamborghini, Ferrari or ANYONE) is going to warranty, repair or replace an engine if YOU screw something up by being ignorant or down right stupid, nor will any car manufacturer give you a brand new car or engine 1 week before the warranty is up simply because you ran it out of oil or water, or decided to blow it up in hopes of getting a new one just before the warranty runs out. And NO ONE is going to warranty, fix or repair an engine where cheap parts were chosen (crank, rods, pistons, bolts, gaskets, etc) to go in it that weren't designed for, or are strong enough for the task. In other words; if you DECIDE to buy a cheap engine and it fails because YOU didn't have the budget to buy an engine that is built strong enough, (or didn't WANT to spend the money to get an engine with strong enough components in it to hold-up), and it fails... that's your problem. ALL manufacturers (GM, Ford, Chrysler, independent engine builders, etc,) adhere to that standard. If it takes $10,000 worth of engine components to stand-up to how you are going to be using it and you choose to spend less... and it fails, there is no warranty that ANY manufacturer or supplier offers to cover that, period!

You can't buy a new vehicle with a 100,000 mile / 10 year warranty, and 9 1/2 years later - or at 99,000 miles drive it down the freeway in 1st gear when it's low on oil to purposly blow it up just so you can get a brand new engine, (or car), from the warranty. Warranties don't work that way. Our warranty is fair, and our unparalleled / world wide reputation speaks for itself.

If you think an engine that comes with a 2 or 3 year warranty is going to run better, or last longer than one of ours with a 1 year warranty, then go ahead and buy "their" engine simply because the warranty is longer. A longer warranty means NOTHING when it comes down to the quality of the parts and machining, the craftsmanship / experience / expertise & track record of the builder, nor the fit and finish of the components like we do. NO ONE'S warranty will cover anything determined to be neglect, abuse, etc. no matter HOW long of a warranty you get with the engine. Just remember that...

Contrary to popular belief, factory Warranties (GM, Ford, Chrysler, etc) do NOT cover "performance" parts or engines, or ANY "competition" use. It's all below in black and white right from their warranty pages.

For those of you who are MOPAR fans, NONE of their performance parts (P prefix) come with ANY warranty what so ever! And for you Hemi fans, including the 426 and new Gen II series 472, 528 and monster 572 Hemi's, those ONLY come with a 90 day warranty that excludes ANY performance and/or "competition" use (full throttle is legally defined as competition use). Here is the warranty info right from MOPAR for ALL of their performance (P prefix engines and parts).


Mopar Performance parts beginning with a “P” prefix are sold “as is” unless otherwise noted. This means that parts sold by Mopar Performance carry no warranty whatsoever. Implied warranties, such as warranties of merchantability, are excluded. (An implied warranty of merchantability means that the part is reasonably fit for the general purpose for which it was sold). The entire risk as to quality and performance of such parts is with the buyer. Should such parts prove defective following their purchase, the buyer and not the manufacturer, distributor or retailer, assumes the entire cost of all necessary servicing or repair. Chrysler, Jeep® , Dodge and Ram vehicle and parts warranties are voided if the vehicle or parts are used for competition. The addition of performance parts does not by itself void a vehicle’s warranty. However, added performance parts (parts not originally supplied on the vehicle from the factory) are not covered by the vehicle’s warranty, and any failure that they may cause is also not covered by the vehicle’s warranty.


Mopar Performance Crate Engine Assemblies not used in competition are warranted for “parts only,” AS DELIVERED against defects in materials or workmanship for 90 days from the date of purchase. The following parts, if defective, will be replaced on an exchange basis for 90 days: engine blocks and all internal parts; cylinder head assemblies; intake manifold; core plugs; valve covers; oil pan; timing gear; water pump; gaskets and seals. See your dealer for a copy of the limited warranty, which contains additional terms and limitations. (In other words; if you buy a crate engine and the block is bad, it eats a piston, a lifter fails, etc, they will EXCHANGE it for another one, which means YOU get to disassemble the engine to GET that bad component out, and pay for whatever labor that may entail, then pay for the shipping to return it, and again pay for the shipping to get it to you, etc.)


Except parts as listed above, certain parts from Mopar Performance sold over the counter or wholesaled are warranted against defects in workmanship or materials for 12 months/unlimited miles for parts exchange only.

These parts are identified in this catalog as having a specific part number structure. Part numbers starting with “P” are not covered under the 12-month warranty. Other parts listed in this catalog without a “P” prefix part number are covered under the 12-Month Limited Warranty described here. See your dealer for a copy of the limited warranty, which contains additional terms and limitations. Parts installed on a Chrysler, Plymouth, Jeep® , Dodge and Ram vehicle by an authorized Chrysler, Jeep® , Dodge and Ram dealer are warranted for 12 months/unlimited miles for parts exchange only. See your dealer for a copy of the limited warranty, which contains additional terms and limitations.

Just an FYI; Full throttle pulls, street racing, burn outs, over revving, etc ARE "legally" considered "competition" use. You do NOT have to be in a sanctioned race or ON a race track to be considered "competition". Get a ticket for street racing and the charge on the ticket is usually written as "competition".

So... does any of that sound like a warranty that's unconditional, or that'll back or cover anything that goes wrong?

Let's have a look at General Motors warranty information & coverage.

For those of you that believe a new "factory crate engine" warranty covers everything on the engine, and/or has no limitations, you are in for a rude awakening to reality. It is a fact that they exclude the exact same things that we do. Below is a copy right from GM's crate motor warranty sheet that you may want to read, and again, are in for a rude awakening to reality.



• Damage due to improper installation, negligence, alteration, accident, improper use, or any use related to racing, track, or competition. Proper vehicle use is discussed in the vehicle Owner’s Manual. In addition, coverage does not apply if the odometer has been disconnected or the mileage reading has been altered.

• Damage caused by lack of proper maintenance as described in the vehicle’s original Owner’s Manual / Maintenance Schedule, failure to follow Maintenance Schedule intervals, or failure to use or maintain proper type and levels of fluid, fuel, oil, and lubricants recommended in the Owner’s
Manual / Maintenance Schedule. Proof of proper maintenance is the owner’s responsibility. Keep all receipts and be prepared to make them available if questions arise about maintenance.

• Damage as a result of overheating, contamination, or lack of lubrication.

• Damage caused by a turbocharger, supercharger, nitrous oxide, or similar
product, which is not an approved GM Performance Part or Accessory.

• Racing engines and/or their components.

• Use of components in excess of maximum torque specification.

• Damage as a result of modification / replacement of torque converter
that is part of transmission assembly.

• Loss of time, inconvenience, loss of use, or other economic loss.

• Vehicles registered and normally operated outside of the United States.

• This warranty does not apply to any unit installed under the General Motors
New-Vehicle Warranty.

So... does it sound like you can buy a crate engine and go race it, or hot rod it around and when it fails they'll simply fix it or give you a new one? Hardly! Welcome to reality. Our warranty is no different.

ZShack Warranty Information

Engine Warranty: All machining and assembly performed by ZShack, will have a non transferable, out of chassis, 12 month limited warranty against defects in workmanship. We guarantee that all machining, clearances, the types of components / parts selected, gaskets & seals, torque specs, surface finishes & assembly are correct and accurate for your engine's intended application. There isn't much more left to guarantee.

Simply put; if an engine fails as a direct result of poor machining, improper finishes, improper clearances, improperly installed parts or poor assembly on the part of ZShack, then the parts needing to be replaced, as well as the labor to do the repair to the engine itself (out of chassis) shall be the responsibility of ZShack. We stand behind OUR work!

All engines have an "out of chassis" guarantee". If in the rare event of a problem, any labor to remove and replace the engine assembly, and/or part(s) needed to perform the removal or installation of the engine assembly to repair the problem are NOT covered under this warranty and shall be the sole responsibility of the customer. Responsibility for the labor charges to diagnose a problem will be determined by who was at fault for the engine's problem. In other words; if the problem was a result of poor machining, bad fit and finish, or bad assembly of the parts, then the diagnose & repair labor will be the responsibility of ZShack. If the problem was found to be a result by the customer, (intentional or unintentional), then any and all labor to diagnose and/or fix the problem shall be the responsibility of the customer / owner. Here's an example; If you go out and buy some "crate engine" out of a magazine that boasts about having a 2 or 3 year warranty and something goes wrong, do you think they are going to pay you for the labor to remove the engine and then re-install another one for you? Do you think GM or Ford offers anything like this on their crate engine warranties? Hell no! Just read their warranty info we posted above.

Examples of poor machining and poor assembly on our part would be; poor fit and finish of the block, installing the wrong sized pistons, incorrect ring gaps for your application, installing incorrect size bearings, installing the front or rear main seal backwards, installing gaskets upside down or backwards, allowing clearances to be too tight or too loose for the intended application, installing the rods and/or pistons backwards, mis-torquing bolts, and so on.

Any and all parts used in (or on) engines shall be guaranteed solely by the manufacturers of those parts, (if any given or implied by the manufacturer). Most manufacturers of “performance”, race, or off road parts do not offer or imply any type of warranty, and nor shall ZShack, or imply, any further warranty on such parts. If engine failure occurs because of a defective part, any labor for inspections and/or tests needed to be performed to determine the cause of the failure is solely the responsibility of the failed part manufacturer and/or the customer. We do not "extend" or offer any further warranty than what the part(s) manufacturer offers (if any) for their components.

If a failure or problem occurs and it is determined to NOT be caused by poor workmanship or machining on the part of ZShack, and was determined to be caused by the customer in any way, shape or form, then the costs of the parts, as well as the labor for the repair, including any additional charges will be the sole responsibility of the customer. Customer’s have the right to NOT continue with any additional repairs, but would still be liable and responsible for any charges for parts and labor up to that point. If a customer refuses to pay fees due after work has been performed, then the engine, and/or vehicle, will have an immediate “Express Mechanics Lien” placed upon it, plus a $40.00 per day storage fee.

ZShack ONLY uses the highest quality, name brand parts for each application and in no way shall be held liable for a part’s failure due to unseen defects in manufacturing, flaws in forgings, stampings and castings or in the initial factory machining process of the parts themselves. Being that we do not make the parts, we have no control over the underlying quality of the parts and must rely on the quality, workmanship and reputation of the parts manufacturer.

Any warranty claims as a result of failure caused by a defective part must be taken-up with the part's manufacturer and will be up to the manufacturer's discretion as to the coverage and compensation. No other claims shall be covered and NO compensation will be paid out for loss of work, temporary transportation, towing charges, property damage, storage fees or for medical fees of any kind, or for ANY reason.

Guarantee / Warranty Exclusions: ZShack does NOT give, imply, nor extended ANY further warranty what so ever, other than our standard 12 month, out of chassis, limited warranty as described herein on eligible engines against defects in ASSEMBLY and MACHINING. ANY and ALL guarantees on engines will be voided if diagnosis, alterations, repairs or modifications are performed by anyone other than ZShack, as we will not guarantee someone else's work or honor someone else's claims or opinions without our prior authorization first.

There is no warranty and no guarantee what so ever, on ANY used engine, engines containing used or re-used parts, containing customer supplied parts, containing parts that have been modified or altered from their original state, or on any engine receiving a “freshen-up” or a partial or incomplete rebuild, nor on engines intended for, and/or used for racing, off road or marine use.

Any and all guarantees and warranty rights will be void on ANY engine that has been damaged (directly or indirectly) as a result of customer ignorance, neglect or abuse. This includes, but is not limited to; customer forgetting to install or improperly installing the oil pump, oil pump pick-up screen or oil pump drive / or any other engine related parts that are installed incorrectly, failure to hook-up or install properly working instrumentation - such as an oil pressure gauge and a water temperature gauge. Failure to install proper gaskets, improper tuning of the engine, improper matching of parts (both internal and external), improper vacuum hose hook-ups, customer neglect, lack of sensible care and maintenance or just plain ignorance, abuse, which can include, but is not limited to, improper camshaft break-in procedures resulting in flat or damaged cam lobes and/or damaged lifters, excessive cranking of engine upon initial start-up, failure to stop running engine when a problem or “unfamiliar sound” has been noticed, over heating and/or failure to stop running engine when over heating occurs, failure to stop running engine when low oil pressure is observed, incorrect fuel type, inadequate fuel supply - (too much – causing cylinder wash down, or too little causing too lean of a mixture and too much heat), insufficient octane, incorrect ignition timing, blown head gaskets (for ANY reason), inadequate oil viscosity, failure to add zinc additive into the oil, failure to change oil and filter after initial break-in period, too much oil in crank case, insufficient crank case ventilation and/or poorly working PCV valve system, over heating, over revving, racing or extreme use, pulling loads too heavy for the engine, blown exhaust gaskets when a modified or after market exhaust system is installed (such as
headers) or in the event of worn-out exhaust manifolds and/or pipes are re-used, and so on.

Oil & Water Leaks: ZShack guarantees that all seals and gaskets are installed correctly according to the manufacturer's installation guidelines. We do not guarantee or warranty parts or labor against oil leaks in any engine where any inferior after market, used, modified or customer supplied parts are installed UNLESS a gasket or seal was installed incorrectly.

We do our absolute best to avoid and prevent any engine from having leaks of any kind, and 99% of the time we achieve that goal, but on rare occasions where a re-used part or a poorly manufactured or "flimsy" aftermarket part is used, a small leak may occur. Most gaskets and seals (for oil pans, timing covers, valve covers, water outlets and so on) can only be installed one way. High grade secondary sealers (such as silicone) are always used along with the gaskets to ensure a good seal. If gaskets and seals are installed correctly, (not backwards or upside down), and are in new condition when installed, then the cause of a leak would be due to the poor quality and/or poor fit and finish of the part, (such as aftermarket oil pans, timing covers, valve covers, water outlets, etc.), as well as old, worn out, damaged or warped original parts, and therefore we make no guarantees against such parts leaking. Most of the time we will be glad to take a look at what ever the problem may be and do our best to make a quick fix of the problem, but that is as a customer courtesy only, and at the sole discretion of ZShack to do so. Under the actual guidelines and rules of our standard 12 month limited warranty, any labor to diagnose and/or repair such leaks is solely at the discretion of ZShack.

Labor Warranty: Labor for installing engines, transmissions, rear-ends, parts & accessories shall have a 90 day guarantee that the parts / items are installed correctly, or as specified within the manufacturer’s specifications or guidelines. Custom fabricated parts, parts that are used, modified, old, fatigued or worn out, or parts that are welded to the vehicle or used for any race, competition, off road or marine use are excluded from any guarantee of any kind, and shall not be covered under any warranty what so ever.

Completion Date and Time: There is no guarantee or certainty on dates or times as to when (exactly) an engine will be completed. Custom built engines require much more time to machine, clearance, port, balance, and complete than stock - factory spec engines and require special ordered parts from numerous suppliers across the nation and around the world. It is common that some parts need extra special attention, such as extra machining to make fit properly and certain tasks take much longer than what would be normal for a stock engine or vehicle. Also, some parts may be on back order and are not available at certain times. Some tasks can not be performed and numerous parts can not be ordered until certain tasks have been performed in a given order such as after machining, balancing or porting is done or after partial (or complete) initial assembly of the engine is done to determine such things as internal clearances between rotating parts and the engine block, ring gaps, piston skirt clearances, compression heights, head gasket thickness and so on. Because of this, no guarantees are made as to when an engine will be completed. We take no responsibility for delays in completing an engine that are out of our control, and we will not be held responsible for any losses the customer may have such as missing a race, missing a car show or anything else relating to a later than expected completion date.

Accidents, Injury or Death: ZShack shall not be held liable or responsible for any reason in the event of injury, death or property damage as a result of misusing performance engines and/or vehicles on the street or race track in any way. Performance engines and cars require more precise driving skills and a higher sense of responsibility on the part of the owner / driver. Losing control of the vehicle, breaking related and/or non related parts, (both on the engine or vehicle), racing or just plain stupidity on the part of the owner / driver is not the responsibility of ZShack.

Engine & Car Performance: High Performance engines do not run and perform like factory built, stock engines. Additional parts may be required to get the full potential out of a high performance or racing engine including lower rear-end gears, higher stall torque converters, a modified and/or stronger suspension, better breathing exhaust systems, a more efficient cooling system and so on. ALL modified, high performance and racing engines require additional tuning and care than a factory stock engine and may have certain “quirks”, such as low idle vacuum which will result in power brake boosters and other vacuum operated devices to not functioning properly, idling differently from time to time, the use of running higher octane fuel, "dieseling" on hot days if ignition timing is incorrect or octane is insufficient, and so on. Performance engines have different (wider or greater) internal clearances than stock engines. This includes but is not limited to; ring gaps, piston skirt to cylinder wall clearance, main and rod bearing clearances and so on. It is common for performance engines to use a bit more oil than a standard, stock engine. It is also common for a performance engine to show a little smoke coming from the tail pipes (although not excessive) due to the increased ring and piston clearances and greater compression ratios. This is especially true in engines set-up for using Nitrous Oxide or turbochargers. Do not expect a performance engine to start, idle or run like a new fuel injected / computer controlled engine, nor should you expect good gas mileage out of a performance engine.

Estimated Power Output: ZShack will not guarantee the exact power output of any engine (within reason) unless the customer has paid additional fees to have the engine
put on an engine dyno and tuned for such power rating by ZShack. Power loss and/or poor performance from an engine (or vehicle) due to incorrect or improper tuning, the mismatch of parts and/or components, or any other measures needing to be addressed by the customer to get the full potential out of an engine (or vehicle) is solely up to the customer and NOT the responsibility of ZShack.

The Bottom Line in Plain English: It's pretty simple. If an engine fails as a direct result of something we did as far as workmanship, (fit, finish, machining or assembly directly performed by ZShack), then we will fix it as stated within the guidelines previously stated in this warranty. This means that if we install the wrong sized bearings or the wrong sized crank, or the wrong sized pistons, or did some sub-standard machine work and the engine seizes-up, or is so loose that it can't maintain decent oil pressure and knocks like a Jehova's Witness on Sunday morning at your front door, we will repair the problem (out of chassis). It also means that we won't cover anything if something goes wrong as a result of the owner misusing, abusing or plainly screwing something-up, such as beating the crap out of it, over revving it, racing it, running it out of oil, running without an air cleaner and letting dirt and crud get into the engine, or letting it overheat and cooking it to death, or improperly timing it which results in internal damage, or running a tune that is so rich that it causes "cylinder wash down", or so lean that it creates too much heat and cooks or melts internal or external components, or anything involving poor tuning or incorrect handling the engine. It should be a "no brainer" that if the engine is over revved and it pitches a rod or valves kiss the pistons from valve float. That it is the owner's problem and not ours! ANY engine will "blow-up" if it is misused or has the crap beaten out of it, no matter how well it was built. We won't fix something that isn't our fault, period.

If the timing is off, it can either make the engine run hot and act like a complete turd, or it can cause it to "ping" and blow-out head gaskets, or even break-off the side of a piston. We won't take the heat for someone else's ignorance. If an engine is built right AND tuned right, it will run great for a long time. Our reputation backs that up, but if an engine isn't tuned correctly or matched-up to parts that "compliment" the rest of the engine, then it's going to run like crap and could cause serious engine damage which is NOT our fault unless of course, we did the tuning or installed the mismatched parts.

If it runs bad because of something we did, such as installed the timing belt a tooth-off, or did bad seat work on the heads and the valves don't seal very well, or anything like that, then again, that is OUR problem and we would fix it within the guidelines of our warranty.

So in a nut shell; we stand behind OUR work. We do great work and make sure that everything we do is correct before an engine ever leaves the shop. We just want to make sure that everyone is totally clear on where we stand as far as backing up our engines. What we don't stand behind is engines and/or problems that we didn't cause, or that are out of our control after the engine (or vehicle) has left our shop. It's pretty simple.