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TR4/4A tr4 crankshaft-my prep-PICTURES

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trfourtune

Jedi Knight
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Hi all,
though i would post some pics of my crankshaft i have prepared before sending it out for balancing and nitriding. I have shown one of my stock ones next to my prepped one for comparison.
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Wow, pretty!
What does "preparing" mean?
 
VERY nice!
Did you magnaflux?

Jim
 
Yes, magnaflux first so you know you are starting with a good crank.
This is what Kas did for his Sebring cars. His picture doesn't do justice to what he did so i posted mine. Take big hand grinder with 40 grit body grinding disc and take out all the rough surface from casting, machine marks, and the extra balance bobs. reduce the roughness with progressively finer discs to about 120 then go to sanding discs to 600. radius all corners (not the journals themselves of course) then finer sanding finishing off with polishing.
Point is to remove all surface roughness to reduce stress concentrations and as an added bonus makes the surface slippery to the oil so it doesn't cling and hopefully reduce drag freeing up a hp or 2.
About 100hrs worth of time. Kas did 4 cars like this. Just shows you how hard he worked. Blood, sweat, and ibuprofin! There are better and easier ways to do this now days but i wanted to save some bucks and do it myself.
Rob
 
Maybe I'll name my block prep post (when i'm done with the block) "blood sweat and ibuprofin", but it doesn't look near as sexy as the crank. Hint, similar type of prep INSIDE the block. (boy are there ever a lot of nooks and crannies in the block!!!
R
 
Wow, a work of art!

I sent my crank off to Shaftech last week to have the same thing done. They will magnaflux, ion nitride, balance, polish, turn, lighten and index it for me. I haven't received a price on all that yet, but hopefully it won't be to astromnomical.

Did you remove the plugs from your crank to clean the inside out?

I'm amazed at the amount of crap inside these stock blocks. There are more casting lumps and bumps than a teenagers face with diblilitating acne. Also, many of the passages are almost halfway closed up. I'm on my way today to get some grinding and polishing stuff to do the inside of my block. I tried it last night with a little Dremel and I estimate it would have taken about 4.25 years to complete using this tool. Hopfully, a die grinder will do better.
 
I tried to get the plugs out before giving up. I plan to have the machine shop remove them and install new ones when balancing. I hope to get everything ultrasonic cleaned. no scrub brush can do what ultrasonics can do.
I use an air die grinder and a lot of different bits for inside the block. You WILL be using your demmel a lot, after the air grinder use, with the METAL bit type ends/cutters as well as others. I also spent a whack on cratex polishing bobs for the crankshaft in the really difficult spots. They are great.
I think my material supplies for the crank added up to about $100 canadian.
I have the flexible extension for my dremmel and use it almost all the time. Can't do without it. There are sharp corners and very very rough casting areas to deal with. I suggest you look at the path the oil takes from the pump to the filter then back into the engine, rather torturous with lots of SHARP bends.
Rob
 
I don't want everyone to know what i've got, just you guys. So when i hopefully smoke some cars with my old 4 banger, it will really embarrass the other guys.
Especially if they see that old lump of iron under the hood!
and to quote Lance Armstrong:
"It's what's inside that counts"
Ok, enough showing off and bragging-thanks All.
R
 
Yup, got it. Got into a 'period' drag race with a restored 50's Ford V8 in town. When he caught up at the next light..."Is that thing stock?"....it is too (almost).
 
I'm curious too how much it would cost to purchase a crank in this condittion, or one that has been fully prepared in this fashion?

I'm new. :thankyousign:
 
1. you can't buy one like this- you can buy a billet crank for about 2000 british pounds plus shipping then you would have to have it sent to someone that does "super finishing" ("raby's air cooled type 4 engines" might do it for you or know where to go-check out their site)
2. you could take a stock crank to a machine shop and have the crank machined to take off most of the nasties first but would still require a bunch of hand work-say 8-16 hrs machine shop time (no hand work) at somewhere between 50-100 $/hr.
3. Add a bunch of hand work say 16 hrs before sending it out for superfinishing.
4. Convince someone to do what i did without ruining it-i would want a dammage claus.(IF, you could convince me, i wouldn't do it for less than $50/hr x 100 hrs=$5000.)It's HARD WORK. A lathe would make it much easier and quicker but i don't have one. If you have a lathe and a milling machine, you could cut down the time. this is when friends with machine shops comes in really handy.

so no matter what, it would be EXPENSIVE unless you did it yourself.

YOU HAVE TO PROTECT THE JOURNALS AGAINTS ERRANT GRINDING!!!

I wrapped my journals in thin cardboard (about 6 wraps) then a band of sheet metal wrapped around then held with bailing wire (or duct tape).I covered the 2 foot strips in duct tape first. The edge of the sheet metal must be covered to protect the sides of the jounals.

So- nothing is free.
good luck
Rob
 
Rob, the crank looks beautiful, I admire your patience and determination!
Regarding the counterweights- they look smoothly finished but it does not appear you knife-edged them for windage, any reason for that?

A suggestion for inside the block- the NASCAR boys deburr the block then paint it with a high temp paint, I think Glyptol is the name or type of paint, to improve oil drainback. A lot less work than polishing!
Great job!
Simon.
 
Simon,
i think to knife edge, it should be done with proper equipment otherwise the balance would be extremely out of whack before balancing(lathe,crank grinding machine, etc)-mine will be bad enough. When i send in for balancing, i will be requesting that major balancing be done by knife edging and grinding the ends of the rod journal outers (the non journal part on the sides) first before minor balancing with holes.
I am primarily interested in strength and fatigue resistance. i do not think there are major benefits with knife edging on such a low rpm motor. Now a toyota 1600 turning 10000 rpm, definitely.8000 rpm-worth while, steet car usually run below 6000 and occasionally run to 6500, probably not.If i was going to race it full time-definitely, every 1/2 hp helps.

I just don't like the possibility of paint coming off, plugging oil galleries, the losing my motor. I always consider murphy's law- "what ever can go wrong, will!" I work in engineering, and see too many examples of murphy's. It takes perfect prep before applying paint inside a block for it to be reliable-perfect surface profile/roughness and cleanliness. Nascar teams have every piece of equipment to make it perfect-i don't. Polishing is reliable.
 
Good answers!
Nascar teams have the budget to run a qualifying engine on oil so thin they have to tear it down after 5 laps, so i suppose flushing out paint chips isn't a big problem!
You have obviously put a lot of thought into this.
 
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