Thread: Common Engine Building Mistakes

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I am sure Tech and a few others can add to this list but here is some info for the guys learning how to do their first build:

MOST COMMON ENGINE BUILDING MISTAKES

• Using an engine (or block or heads or manifold) because you already have it. This is a compromise from the start. Before you spend a lot of money on an engine build, define (on paper) what you are trying to accomplish, is it a low RPM street engine in a 3600 lb car or is it a drag-only engine in a 2000 lb car? There is a difference; a big one. Then, build the engine on paper by making a list of every component's specification. Go thru the list to verify that the components are compatible. Sell those incompatible parts to some other sucker.
• Listening to buddies....they are the poorest source of information in the world. Call the experts. If it is a cam choice, call the cam manufacturer and listen to their advice. Just like asking your buddy about sex, your buddy has no experience in building engines
• Thinking you are going to build a superior engine by cutting corners We see this all the time.....guys will argue that they are building a xx horsepower for little money...but the professionals have to spend twice (or more) the money to get the same horsepower....what do you know that the pros don't? There is a reason for almost every step in an engine built. Skipping steps or cutting corners will not result in a higher horsepower engine....it just will not happen.
• Building an offbeat size engine because it is "cool" or because "everyone has a 350." There are valid reasons for building a 265" or 283" Chevy or a 221"/260" Ford. Being cool is not a reason. 99% of the people that look at the engine have zero clue of the size.....build a big engine and tell them whatever....they will be impressed by how well it runs
• Using parts because you already have them. Wow, how many times has someone written this forum and said "I am building an xx and I have these heads that I have had for 20 years. What a disaster! An engine is a system and every part in the system must be chosen with care. Maybe they have been collecting parts for 20 years to build a specific engine...that's a different story and is OK.
• Buying used parts without verifying what they are. Again, how many times have we seen someone post "I need to identify this cam that I bought really cheap at the swap meet." Why did he buy something that he had not already identified? Buying used parts is risky enough but buying unknown used parts is a poor use of money.
• Choosing parts because of low cost. Realizing that everyone has a budget (yes, everyone), it can be said that it is foolish to compromise an engine build by using a questionable part or a part that is just wrong. If you are spending several thousand dollars or more on a build, why risk the entire cost by installing a "low cost" oil pump or a set of "Chinese" hydraulic lifters? If nothing else, think of the value of your time when you have to remove the engine to change a dumb part. I once knew a guy who bought a rebuilt engine for his car. After installing the engine, he fired it up and it had a bad knock. He went back to the el cheapo auto supply and told them the problem. They gave him another engine. It too had a problem so he got to install not one, not two, but three engines in his car. If he was pretty fast, he may have spent 8 hours on each engine times three. No bargain there from the el cheapo supply house.
• Using a cam (or pistons or heads) without consideration of the total system Just because Hot Rod Magazine used a "super thumper double whammy" grind does not mean it will work in your motor unless you are building the exact same thing they did. Do something really smart and really simple....call the part manufacturer and talk to their tech people. Then, do something really revolutionary....follow the manufacturer's advice.
• Not placing enough importance on the piston ring choice and the required bore/hone procedure for that ring package. The current Hot Rod Magazine has a good ring article. Rings are pretty important to the engine's success. Again, ask the manufacturer.....that cell phone plan you have probably has free long distance so use it!
• Choosing the wrong torque converter for the engine A bit of art and science but there are resources that can point you in the right direction. A wrong converter can turn a hot engine into a dog. Converters are not cheap but you should be able to zero in on the correct one without buying the entire range of stall speeds.
• Relying upon the machinist to not make mistakes Wow, what a mistake to make! If the machinist goofs up, he may not notice the error (or he may not care). Nothing like building an engine and finding out that the clearances are wrong after you spend the weekend installing the thing. Trust no one.....including yourself.
• Choosing a machinist using price as the criteria Just because he will bore the engine for $1 a hole will not make your build a better one. Unless you are building an engine for the demolition derby, you should buy machinist services on quality......
• Not checking everything and not rechecking everything Back to don't trust anyone. Don't trust your measurements, measure a few more times.
• Putting the distributor in backwards or one tooth off. Think thru the assembly and know the theory of how the engine is assembled before you do the final assembly. Every engine has a similar operating theory, just figure out how a Ford indexes the distributor relative to the cam.....it isn't the same as a Chevy.
• Adjusting the valves wrong Wow, we have seen this a lot in CHR. When the instructions say "tighten the rocker arm nut until the push rod play is eliminated and then tighten the nut 3/4 turn" means the VERTICAL push rod play. Twisting the push rod is not play, it will still rotate after all vertical clearance is gone. We all have done it, but we all have learned.
• Putting the timing gear on wrong If you don't understand how to line up the little dots, ask someone or read the instructions....the little dots mean a bunch to the cam. After you put the timing gears on, check it again. Then, check it one more time.
• Improper break in procedure. Engine's in....let's go!! Well, the specific components that you used each have a preferred break in procedure. Follow the manufacturer's instructions. Just because your buddy broke in his car by pouring sand down the carburetor does not mean that it is applicable to your build.

Great post, Robot. I'd add the following:

Not insisting on absolute cleanliness in the assembly. A small speck or rock hard grit can destroy a new bearing or a rotating assembly. Use lots of clean dry, lint free rags. Keep your tools clean and your hands clean. It's take a bit of time, but pays dividends in the build. Nothing like having your hand slip off an oily wrench and jamming your fingers or bunging your knuckles.

Building in low light - light is critical to be able to read precision instruments and measure correctly (more so as my eyes age). I have two double eight foot florescent fixtures and eight double four footers in a 22' x 30' garage and occasionally use some supplemental light.

Working on an engine when you're tired or angry - hopefully this needs no further explanation. It's okay to take our time. Remember that "the demands of the service or the importance of the job are never so great that we can not take time to do it right".

Regards All,
Glenn

Robot, you are the man. Thank you for creating this most sorely needed thread. And thanks Glenn for pitching in.

My first contribution will be lack of knowledge about what you're doing in the first place. I know little or nothing about the workings of a computer, so for me to sit down and try to build a mother board without reading and researching how to do it would be ludicrous. Yet, every day, I find myself lining out the basics for some newbie and trying to fix what he screwed up. Not that I mind doing it, I don't, but if the guy had just done some reading before starting off or had asked some questions before choosing parts that won't work together, he wouldn't be facing wasted money, wasted time and wasted effort.

Secondly, it must be because there is some romaticism surrounding the camshaft that causes newbies to buy the cam first, before they have any clue about anything else in the motor. As Robot said, you need to sit down and line out everything as a COMBINATION based on the intended purpose of the vehicle, the weight of the vehicle, the rear gear, the suspension systems front and rear, the transmission, the converter (if auto), the piston crown volume and combustion chamber volumes, gasket volumes, piston deck height, block deck height, compression height of the pistons, etc., etc. so that you can calculate the static compression ratio. You CANNOT intelligently choose a cam without knowing the static compression ratio of the motor. The cam should be the next to last purchase, with the converter being the last.

This one is important enough to repeat from Robot's list....
"Buying used parts without verifying what they are. Again, how many times have we seen someone post "I need to identify this cam that I bought really cheap at the swap meet." Why did he buy something that he had not already identified? Buying used parts is risky enough but buying unknown used parts is a poor use of money."
NOW HEAR THIS FELLOWS: A used flat tappet hydraulic or flat tappet solid camshaft has only one valid use....AS A DOOR STOP!!@!!! A roller cam can be re-used in the same block or in another block, but not a flat tappet cam. Once you take it out of the motor, it must either be re-installed in the same block or used as a door stop. It will not work in another block because of the variances in machining at the factory when the blocks were manufactured. Once in a while, if you're using bone stock worn out valve springs, you can get by with it if you use new lifters. But 99% of the time, you'll re-use it with stiffer springs and find yourself having to tear the motor down to clean the shrapnel out of the oil galleys so you can build it again with the proper parts. Wasted money, wasted time and wasted effort.

your build is only as good as your parts and your machine work .experience helps you see things that can get over looked .every thing needs to get check new or used i sent many new things back .i seen alot of things that were not right a engine builder and a engine assembler is not the same if you have no control of the machine work then you just screw parts on. that is ok but you better have a good machine shop working with you.

You guys have provided such a comprehensive list that the only thing I can think to add is to test fire the engine if possible on the shop floor before you go to all the trouble of bolting it into the car and have to remove it if some problem develops. Doesn't have to be anything elaborate, just blocking it up so it won't move, a few temporary wires, oil in the pan, temporary tach and oil pressure gauge, a garden hose plumbed into the lower radiator hose. After prelubing it start it for a minute to see if it will start and if any leaks are present. An engine will run quite well sitting on the garage floor.

Our Techs at work do exactly that on every engine we install (and we use only brand new crate long blocks) because it saves a whole lot of work pulling it back out if a problem is found. Just last week a brand new 454 was prelubed and no oil was getting to the rockers..........we think cam bearings were installed off center. If we had installed it we would have had 20 hours labor go up in smoke.

Don

yep we runned them in to at the yard i work at as well .hook the hose to them point the ex out the door wait for a shop worker to walk by the over head door and crack open the carb and shoot water at them. i prime every thing before it go s out the door. with a roller cam break in is not a big deal .still have rings for break in but i plateau hone the way i prep the bores works for me

Our Techs at work do exactly that on every engine we install (and we use only brand new crate long blocks) because it saves a whole lot of work pulling it back out if a problem is found. Just last week a brand new 454 was prelubed and no oil was getting to the rockers..........we think cam bearings were installed off center. If we had installed it we would have had 20 hours labor go up in smoke.

Don[/QUOTE]
the lifter galley plugs .are missing in the front of the block or if a gen 5-6 the1/8 plugs were not in the lifter valley for low oil psi the mark 4 to 6 do not oil thru the cam bearings if the cam bearing were not lined up you would just dry the cam out burn the bearing out and cam the the 1/4 front plugs out you will get low oil psi oil to cam and crank . but no upper oil from lifters to rockers

Awww--I just used to put them together and push start them toward the starting line---they were broke in enough to run by the time they turned around and staged

Don---for ur stated reasons---have seen a few engines where the push rods were filled with cam break in lube on assy and the pump was slow to pump thru on the right side--also had pressure drop around dist shaft housing

you can check upper lubing with drill and prelube shaft without running engine

nothing like tough love hey jerry some of my kids have see abit of that to yep i am sick guy i call my engines kids

Originally Posted by jerry clayton

Don---for ur stated reasons---have seen a few engines where the push rods were filled with cam break in lube on assy and the pump was slow to pump thru on the right side--also had pressure drop around dist shaft housing

you can check upper lubing with drill and prelube shaft without running engine

yep that it will with just a prime rod and no Dist body to let the oil run thru it just dumps the lifter psi on the dist side that a GM dumb deal other then that there great engine

You are right about the distributer hole needing a block off to direct the oil in the right places. At first I thought our shop preluber might be not right, so I went to my shop at lunch time and loaned the guys mine that is set up specifically for Chevy engines.............did the same thing. You could be right about the pushrods being plugged, but no oil was getting through any of the 16 pushrods. Engine went back to Eagle and they are supposed to let me know what they found tomorrow am.

Don

Originally Posted by Itoldyouso

You are right about the distributer hole needing a block off to direct the oil in the right places. At first I thought our shop preluber might be not right, so I went to my shop at lunch time and loaned the guys mine that is set up specifically for Chevy engines.............did the same thing. You could be right about the pushrods being plugged, but no oil was getting through any of the 16 pushrods. Engine went back to Eagle and they are supposed to let me know what they found tomorrow am.

Don

i will bet you the front galley plugs were out .or they will not tell you how big was the cam ? with hi lift the stock gen 6 the stock lifters hang out of the bore the lifter oiling hole in the lifter body hangs out of the boreoil low you have a leak dumping top end oiling galley plugs or lifters that about it less the push rods have no holes in them even with thick lube a 90 hot or better day out oil will flow

Pat, just a stock 310 horse 454 Marine engine. Brand new in the crate. We pulled the sender out and it shot oil out of the hole really well, but even after cranking with the plugs out the rockers are dry.

I think you are right about them not telling us what they find. They are saying if they "find something simple" would we take the same engine back? Told them we would need to talk at that point. Problem is, 454's are getting scarce, so we might have to take this one back.

Don

Originally Posted by Itoldyouso

Pat, just a stock 310 horse 454 Marine engine. Brand new in the crate. We pulled the sender out and it shot oil out of the hole really well, but even after cranking with the plugs out the rockers are dry.

I think you are right about them not telling us what they find. They are saying if they "find something simple" would we take the same engine back? Told them we would need to talk at that point. Problem is, 454's are getting scarce, so we might have to take this one back.

Don

well don if a mild bbc they left out the front lifter galley plugs .you will get good lower end psi but it will not build much with rpm .i would think you may have a hard time getting them to tell you what they did wrong