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Precision Measurement of engine components

Old Feb 10, 2004 | 01:50 AM
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Precision Measurement of engine components

hi guys, I just thought I'd post some pics. I started measuring some of my internal engine components. just starting to check clearances on things like piston to wall, rod and main bearing, etc.

I already noticed that my crower valves have smaller diameter stems than ford stock, so I'll have to double check the measurement tomorrow and then call them to see what's up.

anyway, here are some pics:

the CP pistons were on the money, between the set of eight, I think there was a COMBINED total variation of like .00035 all of the wrist pins were on the money as well, however CP didn't offer a spec for the pin bore diameter, so I guess I'll just have to trust 'em on that one.


mic'ing the crankshaft journals (main and rod):


here is a shot of how the counterweights of the crankshaft were drilled to remove weight to offset the lighter rods and pistons during the balancing procedure:
 

Last edited by superfords; Feb 10, 2004 at 02:25 AM.
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Old Feb 10, 2004 | 01:53 AM
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please bare in mind that all of this work should only be performed in a certified engine "clean room".




in this case, my living room

and under the watchful eye of an experienced assistant:

miller dog on the scene!

later,
chris
 
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Old Feb 10, 2004 | 02:46 AM
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You are one lucky guy.

If I had the know how and the tools I would NEVER let anyone even open my hood and do everything myself


Nice truck BTW, and I can't wait to see what you run!
 
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Old Feb 10, 2004 | 03:27 AM
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i've always wondered about this

how do you know your measuring the widest point?

and when your measuring say the inside of a cylinder, how do you know you've got it at a right angle?


looks fun tho, can't wait til i finally am able to afford that stuff.
 
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Old Feb 10, 2004 | 07:55 AM
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Originally posted by grinomyte
how do you know your measuring the widest point?

and when your measuring say the inside of a cylinder, how do you know you've got it at a right angle?
1. you just have to practice and get a feel for it. I had a difficult time at first, but once you get the technique it's fairly easy. I just center it up and then sort of "feel" by the tension or "drag" on the micrometer. when you get the correct measurement you can slide the micrometer off of either side of the circle that you are measuring, if you go to small, then it will not slide back on.

2. well, if you are using snap guages then you have to feel and eyeball it. if you are using an inside micrometer then you have to have very small hands, but if you are using a dial bore gauge, then... well, just stay tuned for pics...

later,
chris
 

Last edited by superfords; Feb 12, 2004 at 10:20 PM.
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Old Feb 10, 2004 | 08:22 PM
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well boys and girls, I've run into a bit of a problem.

the problem is with Valve Guide-Stem clearance.

here are the specifications:

Valve guide bore diameter 7.044-7.015 mm (0.2773-0.2762 in)
Valve stem diameter — intake 6.995-6.975 mm (0.2754-0.2746 in)
Valve stem diameter — exhaust 6.970-6.949 mm (0.2744-0.2736 in)
Valve stem-to-guide clearance — intake 0.069-0.020 mm (0.0027-0.0008 in)
Valve stem-to-guide clearance — exhaust 0.095-0.045 mm (0.0037-0.0018 in)
Now here is my problem, my aftermarket Stainless Steel 1mm oversized valves have a stem diameter of approximately 6.952mm (.2737") on BOTH intake and exhaust valves

what this means is that the intake stems are undersize or smaller than stock ford size. what that means is that the valve stem to guide clearance will be excessive on the intake valves.

granted, we are talking about some VERY small measurements here, and thus some VERY minor differences, however in theory, this added clearance COULD cause accelerated valve guide wear leading to valve seal damage which would of course create an oil consumption and smoking tailpipes condition.

so I called the valve supplier and they didn't have a clue but are supposed to be calling me back tomorrow.

I know A LOT of folks just slap these valves in and let 'em eat. I just hate to spend this much money on an engine and look the other way or "close my eyes and cross my fingers" that everything will be ok.

the other variable to consider is that there may be some justification for the discrepancy due to the fact that the new valves are made from a different material than the stock valves, but if that was the explanation, then why not have the exhaust resized as well?

what to do, what to do?

later,
chris
 
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Old Feb 10, 2004 | 08:33 PM
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well after thinking about this "problem" some more, I suppose I may just "let it eat".

the difference between a middle of the spec ford intake valve (6.985) and my aftermarket intake valve (6.952) is only .033mm or what amounts to Three Hundredths of one Millimeter A VERY TINY AMOUNT

I guess I'd just like to be safe on something like this, but I still don't like the fact that it doesn't fit within the specs.

maybe I'm just being alittle ****, but hey with the amount of time/money I've got invested, that's forgivable isn't it?

later,
chris
 

Last edited by superfords; Feb 10, 2004 at 08:35 PM.
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Old Feb 10, 2004 | 09:01 PM
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Or .0013" for the rest of us......pretty close! Even less than .001" under if you use the MIN spec.

Hey, if you're guides measure 7.015mm (MIN) , then you have a .063mm/.0025" clearance----just BARELY IN!!!! Hoo Hoo!
 

Last edited by LightStruck; Feb 10, 2004 at 09:21 PM.
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Old Feb 10, 2004 | 11:37 PM
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Crower Cams has been a high performance supplier for more years than I can remember. I'm surprised that they didnt suggest some "recommendeded" valve stem clearance dimensions with your oversize valves for certain engine combinations. I would want to talk to them to see what they suggest. I know it would make me feel better knowing that my "valve guide to stem clearance" was what they recommended for my particular engine combination.
 
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Old Feb 12, 2004 | 04:22 PM
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I talked to the "ford guy" at Crower, his answer was something like, "just put 'em in there, you'll be ok".

very reassuring

anyway, on to bigger and better things.

today's class, rod bearing clearance measurement.

you need just a few simple measuring intstruments:


just kidding, you don't need ALL of that stuff, pictured are 0-1" mitutoyo micrometer, 1-2" starrett micrometer, 2-3" starrett micrometer, 3-4" mitutoyo micrometer, a dial caliper, a set of snap guages, and a mitutoyo dial bore guage.

anyway, first step after you've measured your crank journals is to set your appropriately sized micrometer (in this case the 2-3") to your crank journal size. mine measured about 2.0864". lock the mic down at that measurement.
 
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Old Feb 12, 2004 | 04:32 PM
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next insert your dial bore gauge into the measured opening of the micrometer and zero the dial bore guage indicator.


note: at this point you should have already inserted the rod bearings into the big end of the rod and torqued the rod bolts to the full torque recommendation as if they were installed in your motor.

then transfer the dial bore gauge over to your connecting rod.



the dial bore gauge is self centering side to side, but you'll need to slowly for lack of a better term "wiggle" the instrument up and down until you come up with the largest measurement.

in this case I came up with:

or .0026" this is the difference between the rod with the bearing installed and your crankshaft journal. in other words, this is your "clearance". which just so happens to fall very nicely within the specified .0025-.00275 range!

check all 8 rods and you are done, assuming that everything comes out within specs. if not then you'd have to either try some more bearings, have your bearings coated, or scotchbrite your existing bearings.

basically this is the exact same procedure I'll use to measure my freshly bored and honed block. to make sure that my piston to wall clearance is correct.
 
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Old Feb 12, 2004 | 04:37 PM
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im seriuosly jealous over here. I don't even care about driving it, i just wanna build it.
 
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Old Feb 12, 2004 | 04:39 PM
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here are a few more shots of the main instrument I'll use to measure the rod and main bearing clearances, and also my piston to cylinder wall clearance.

It can be set up (using the interchangeable anvils and washers) to measure holes anywhere from 2" to 6" in diameter. dial bore gauges can cost anywhere from $100 to $3000 dollars.


measuring end:


as always, miller closely inspects my work:


later,
chris
 
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Old Feb 12, 2004 | 07:33 PM
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what kind of valves did you buy? the ferreas? i went with the modmax oversized
 
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Old Feb 12, 2004 | 07:44 PM
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I got my valves from Crower, I kinda sorta suspect that they may all be ferrea valves though no matter where you get them from.

later,
chris
 
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