Blueprinting an Engine

[JMD Engineering]

I recently graduated from UTI and learned ALOT. one of the classes was all on performance and how to blueprint an engine. We LITERALLY mic'd every part of a the motor (main journal, bores, cam lobes). The teacher said, when building a new motor, you should mic EVERYTHING and keep it in a tolerance of spec, as new parts arent necessarily 100% true. This is understandable... but is it really necessary?

I understand the mathematics behind the motor (how big intake valve should be in terms of bore size, how long exhaust headers should be in terms of chamber)... so i know how to make an engine be efficient. But do you engine builder ACTUALLY mic ever piece of the motor and mill/oversize/undersize accordingly, even though bought new? Or do you just assume the size of a crank journal and get the correct size bearing accordingly?

hope this sparks some conversation. as I am very interested.

 

[SVT32VDOHC]

That's too much work, I just slapped a supercharger on my car and called it a day....lol


But...I know what you mean....ad good engine builder should check that stuff, but I doubt that most do.

 

[tmoss]

there is a diference in an engine builder and an engine assembler.........Devil's in the details and it's why you pay more to some shops than others.

 

[cenok is family]

there is a diference in an engine builder and an engine assembler.........Devil's in the details and it's why you pay more to some shops than others.

truest statement ever.

 

[reddog]

It depends on how long you want it to last, by just slapping it together you take a chance on overlooking something, that can cost you everything you just spent on building the motor. Now is that going to make it bulletproof? No, but you can at least be sure that it wasn't something stupid! And yes, not all machinist work is top notch, do your home work on finding a good one. In my area I recommend Dave Irwin @ Millwood Machine shop in Kalamazoo, Michigan. He's done machine work for me for over 15+ years and is the best I've found so far, I'm sure there are better ones out there, but I will stick with Dave.

 

[JMD Engineering]

thanks guys. got some good info :]

 

[FastDriver]

I put all billet internals and custom pistons in my 331 Dart Block. I was not taking any chances. Even though I could assemble the motor myself, I did not trust myself not to make any stupid mistakes. So I took my stuff to Dayton Performance Motorsports. Michael Bell subcontracted the machine work and then measured everything himself after it came back from the machine shop. So, it was basically a redundant system where it had to pass the machine shop and Michael, too. That all makes me feel better about the motor going together. I'm no millionaire. So this expensive motor has to be done right the first time. You damn well better bet that I expected all of the measurements to be done right.

Chris

 

[tmoss]

In the vast majority of cases, it is better to get a pro to do engine work if you do not the tools, knowledge and patience to build or modify high performance engines and parts. I'm sure you have all heard the epxeression "not enough money to do it right the first time..........but plenty of money to do it over."

 

[BK_CAULEY]

there is a diference in an engine builder and an engine assembler.........Devil's in the details and it's why you pay more to some shops than others.

best statement ever. tolerances make a difference. thats why some factory motors make more power than others.

 

[moostangvert]

there is a diference in an engine builder and an engine assembler.........Devil's in the details and it's why you pay more to some shops than others.

damn, you stole my thought. i always degree my cams too before i folow through with the install. details, details, details

 

[2000xp8]

I'm sure you have all heard the epxeression "not enough money to do it right the first time..........but plenty of money to do it over."

Haven't heard that one before, great saying.

On my most recent project i've been working on, the engine builder mic'd it all up and gave the shorblock the full treatment, cost more and took longer.

 

[Vipersix]

A good friend of mine has been playing around with cars for probably 40-some years. Over the years he has been accused of exceeding the various restrictions placed on race motors. Every time the inspection team disassembled his motors they came up empty handed. The reason his motors were so much more powerful than his competitors was primarily due to his attention to detail. Of course, this is in a sport in which the difference of 2 or 3 horsepower can mean victory or defeat.

On your average motor used by the folks on this forum, a complete and accurate blueprint job is unnecessary. A general truing of the crank journals and aligning the cylinders is probably a better bang for your buck. But if you intend to race competitively and want to crank the RPMs up beyond 7k, you won't survive without it.