Well I am going to disagree with the idea that the term 'bluprinting' as used in this context is making "All Ideal measures (---) as close to the middle value as possible". In EVERY engine I have 'bluprinted' (really a bad usage of the term vis a vis engine building) I have 'fudged' the legal limit in one direction or the other. Seek out the pistons that give the HIGHEST compression ratio, the LONGEST rods, the LONGEST stroke, the LIGHTEST flywheel/clutch, the HIGHEST ratio cam/rocker arm,etc. and carefully rebalance and grind and polish everything legally possible within the rules. It is all about MAXIMIZING performance and in many cases this process violates the "spirit of the rules" but then that IS the name of the game is it not? It is a business and a brutally competitive business at that. No one is willing to pass up even the smallest advantage.
I tend to agree with Rod. For competetion, make everything as advantagous as possible. The other part of blueprinting was the recording of every measurement and calculation possible. This way, if there was a problem, the exact dimensions or clearances could be altered on the next engine. Trying to diagnose a clearance after the engine blows up may be impossible.
Balancing and blueprinting (the understanding). All motors are balanced and blueprinted to OME specs. This can be compared to blueprints in houses which most people are familiar with. Example: Receptacles--so many inches from the floor, so many inches from the corner. Countertops--so many inches from the floor. Now you'll change the blueprint to wheelchair accessibility. Countertops will be lowered, receptacles will be raised, light switches will be lowered, etc. Now let's play with a motor. 5-30 oil, .001 rod and main clearance, piston to cylinder walls, .0015. This is mama's car. Let's hop it up! 40weight racing oil, .003 rods and mains, .0025 to .0035 piston to wall clearance. In other words, blueprinting is to the customer's driving and performance desires. Piston and bearing clearances change with RPM demands.
You miss the point. We are talking about 'bluprinting', not 'hop up'. The term 'bluprinting' (bad choice of word IMHO) refers to maxamizing an engines performance by building to the OEM tolerances that will yield the best performance in whatever venue we are building for. This scheme of 'bluprinting' came about by racing organization's stock engine classes. It is just human nature to use whatever is at hand to go faster in ANY race class. In the case of 'stock' classes, we tended to throw money at it by 'bluprinting' to stock(???) OEM specifications. I am not sure if the origin of this term was from dragracing in the 50's but, I suspect it WAS. As a result of this scheme of 'bluprinting' the cost of racing in 'stock engine' classes has escalated to nearly equal that in fully modified classes. It is a shame that the 'limited modification' classes are not used more extensively as they are much less costly overall. SCCA's 'IT' class and 'Spec Miata' are a couple of very competitive classes that are cost effective. NOTE--I did not say cheap, just cost effective as racing classes go.
As to those demensions you refer too---well that IS old school for sure. My latest racing engine intended for use in the 3750 to 8500 rpm range are 0.0015"mains and 0.001" rods with 0.0015"to 0.002" piston skirt with 5W-30 synthetic. Some of the 'factory' stuff is even tighter. These tighter specs are the result of better machining and mfgr techniques, better lubrication etc. Tighter specs result in a smoother revving engine, less vibration from things moving about I suspect. You will have to talk to Larry Meaux or Greg Locock for confermation or denial of that.
I reduced the big end clearances to get a measurable improvement in the sound emitted by the engine. In the end we did it in production by introducing 5 grades of fit in the assembly process. They hated me.
I always wanted to do the mains as well, but had used all my Brownie points up by then.
Skirts is interesting (hmm, yes), we'd love to get a better handle on slap, especially when cold.
usually when an engine builder says blueprinting they are talking about measuring all the components and puting them on paper and deciding what needs to be done from there. ex. port matching the intake manifold ect. but thay could also be talking about engine specs but not likely.that should be done before assembly anyway!
My understanding of "Blueprinting" is when constrained by rules calling for conformation to original or standard specs, the engine builder takes the OEM buleprint spec and works all the tollerances and loopholes to maximum advantage.
By the way Rod, re your response in the Oil's section, the name is Pat as in Patrick, and I hail from the land of the Valiant Charger 265 Hemi in line 6.
------------------------------ GregLocock posted on July 5, 2002 Skirts is interesting (hmm, yes), we'd love to get a better handle on slap, especially when cold.
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Greg, have you tried using any of the piston secondary motion simulation tools out there? I think that Ricardo and MDI/ADAMS both have piston secondary motion dynamic simulation software available, and I've heard the software is good for stuff like that...
To my intense shame we black-box the pistons, so I never got to play with the Ricardo software.
However, I do now have MSC ADAMS Engine, so when I find a convenient time slot that'll get a workout. Late 2005 looks good!
In my opinion the ADAMS slover has a generic problem with internal damping (it obviously handles discrete damper fine), so I would expect to find modelling proportional damping rather difficult. On the other hand the kinematics and the collision modelling works very well. Cheers
I've looked at the specs for the two packages, and if I remember correctly, I think that the Ricardo software did a better job representing the skirt-liner interface than the MDI software did, while the MDI package allows more degrees of freedom in the model. I don't recall reading anything that would lead me to believe that the MDI software can predict wear regions on the skirt, while the Ricardo software definitely can. I look forward to hearing your comments in 2005. Adams engine, from what I've heard, has some pretty sweet features for valvetrain/geartrain dynamics.
How does ADAMS model collisions? I have only limited experience (about 100 to 200 hours) with that software, and I'm not clear on all the details. It's been quite a long time since I used it, too.
When you say that you black-box the pistons, you mean that you give some specs to Mahle or Fed. Mogul (or other) and get a complete piston design back, right? I know (based on some previous work with an engine OEM) that some of those guys use Ricardo's PISDYN in-house, although from what I recall, the features of the software are not fully utilized by them.
Wear doesn't sound like an ADAMS sort of analysis, we write time histories out and then give them to the FEA boys for that.
I don't know how it models collisions, either. I'll get around to reading more about that in 2006 at the current rate of progress.
Yes, black boxing means we don't know what goes on inside the design, which is frustrating but seems to be the way of the future. The trick is writing an achievable but satisfactory spec, and finding a vendor you trust.
it is better than black boxing in the electronics world. in electronics the idea is similar except that the only people who know how the black box work are retired or at a competiters company.
