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This doesn't truly relate to your issues, but ...here goes.
I have a customer that I do a lot of CNC turning for. He also seems to send out enough CNC milling to (I think) justify purchasing one. He's resistant because he is A) scared of the payment, B) Doesn't want to pay to hire a person that can program, set-up and run the machine.
I counter that with....When you send the parts out, you loose control of a few things....ie: quality, lead time.
So you had to send you engine out. I get it, few have the capabilities to do these things...I for sure don't. So we are at the mercy of others....and quite often the "others" don't have the same quality expectations as us.
@PriusLover Looking at the crank a little more closely, it appears those "weights" were screwed into tapped holes then welded. Maybe ask the machine shop why they did what they did and then see if you are still disappointed after that. I know that I have gone into many conversations angry but then I asked that question first and found out they had good reasons for it, then I feel totally deflated and sheepish.
@PriusLover Looking at the crank a little more closely, it appears those "weights" were screwed into tapped holes then welded. Maybe ask the machine shop why they did what they did and then see if you are still disappointed after that. I know that I have gone into many conversations angry but then I asked that question first and found out they had good reasons for it, then I feel totally deflated and sheepish.
I'm definitely going to inquire first and see what exactly they did/why they did it this way before I make my unhappiunhappiness known. Will also take the stuff to another shop to get a second opinion.
How can you tell they are threaded in? Weights are usually a tungsten alloy so not something that can be easily threaded. Maybe they used lead instead of mallory.
So you think maybe its a lead slug that has a steel cap thats welded over it?
There's a difference between tungsten and tungsten carbide. I have boring bars that are steel (good for 3x diameter, tungsten 6x diameter and carbide 8x diameter) and the tungsten ones are not really hard, just dense.
So you think maybe its a lead slug that has a steel cap thats welded over it?
There's a difference between tungsten and tungsten carbide. I have boring bars that are steel (good for 3x diameter, tungsten 6x diameter and carbide 8x diameter) and the tungsten ones are not really hard, just dense.
I've heard tungsten is a pain to machine, not necessarily that it's hard. But yeah if the crank didn't require much weight I could see using lead as it's cheaper. I'll know for sure in the next few days.
Took the head and crank to a reputable machine shop for a 2nd opinion
Valve guide clearance is all over the place. Guy said the .0020 exhaust valve guide clearance would sieze when up to temp.
Said the surface finish definitely doesn't look within the 63-125 micro inches spec.
Said they didn't press in the new valve seats I bought, and that the finish on the seats is very rough.
Originally Posted by brokestroke
Whatever they are there is plenty of weld holding them in place. The bigger question is, is it balance?
We weighed two rods (one with the most material removed one with the least) and small ends were the same, big ends had an ounce difference. He hypothesized the crank welds are from over shooting and attempting to correct.
He thinks it's likely fine to run the rotating assembly, though he agreed the journals didn't look polished.
On all the parts that have been machined there are large burrs. The rods are the worst with some large enough to cut you/scrape off with your fingernail.
Wow, not good. Sounds like very poor workmanship/lack of knowledge and poor business ethics from the shop that did your work. Sorry to hear this. Seems as though they owe you the cost of a good engine assembly for a more competent shop to work with.
Sorry to hear of all this headache and delay
Various machined finishes can look vastly different and have the same RA or RMS. My guess, from 30k feet on the internet, is maybe 125 or a tad better. Without putting a profilometer on it, it's just a guess.
Ya, your second opinion shop seems to know a lot more of what needed to be done. That is very frustrating and sorry to hear. Too bad you weren't closer to us since we have a full engine machine shop too.
For good measure, I would see if the second shop would at least spin up the rotating assembly and see how close the balance job is. If you go ahead and put it together, and it's way off, then you have a lot of work to tear it all back down and rebalance.
Various machined finishes can look vastly different and have the same RA or RMS. My guess, from 30k feet on the internet, is maybe 125 or a tad better. Without putting a profilometer on it, it's just a guess. Google surface roughness comparator.
It's enough such that you can feel the ridges with your fingernail (some ripples with the pad of your finger) when going perpendicular to the machining lines. I took it to a general machinist who has a comparator... He thought it looked within spec. It's hard to say because don't know how shop cut the head.
The first machine shop said the welds on the crank are just welded in existing holes, not mallory since so little weight was required in those areas. The guy who runs the shop wants to see the work, seems rather surprised at what I'm describing.
Could be that the block and balance job are acceptable while the heads were done badly. Everything about the heads seems wrong... Even the valve recession is far off from the measurement written next to it:
Took the head to yet another machine shop who mic'ed the thickness and reported it being a under the min spec, and confirmed that no new seats were pressed.
Took the info today to the 1st shop and after checking the work they agreed to
-Refund the deposit
-Replace the heads
-Pay to have the rotating assembly checked and replaced if it's not in spec.
-Pay to have the block checked and replaced if it's not in spec.
-Pay to have the cam checked and replaced if it's not in spec.
*EDIT* Remembering now that other shops are are booking out pretty far; might be a while before I can get them to check the block and spin up the rotating assembly, so probably better to have first shop just pay for a buildable core engine that I can get started on.
It sounds like they wanted first chance to redo the work on replacement parts... Seemed very disappointed in the situation, with an eagerness to make things right.
Hopefully it's smoother sailing from here on out.
