There is a very reputable shop by me that i called about doing some engine work for me....
i told them i would like to have my crank polished or machined.... and they cut me off right there and said they would not even work on a car that had a machined or re-worked crank.
they said they refuse to touch an engine if it doesnt have a 100% intact original crank.
I have never heard this kinda thing before... i am just wondering if they know something I dont about a "re-build" or re-surfaced crank.
(this is a performance race shop, so maybe they are a lil more anal than most)
they said "if your crank is bad, then get a new one and then we can talk"
does machining the crank really weaken things that much?
they have me all paranoid about machining my crank now....
can anyone confirm or explain this?
I am having a hell of a time finding a original crank for the 2.4.... everything it re-man or machined....
Ha, thats exactly the same boat I am in right at this moment.. My machine shop said the same thing because most re-manufactured cranks are welded back together(journals) and that is a very week point over time after the bearings are attached and then driven.. Also most of the time when cranks are welded back together, that size of the journals are soo far off the stock measurments thats its not even worth working with. We even contaced GM and they dont offer brand new cranks, theirs are also remanufactured!!! Your best bet is to find a stock crank from a motor that is blown and does not have a spun bearing.. Shops can most of the time polish out any wear that is on a normal not spun bearing crank.
I think my shop found me one(going over there today)
But yea, welded crank=bad... And places like Napa, GM, or any other place obviously wont tell you that upon purchase.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
ok but what about minor damage to your own stock crank, and having a shop clean it up for you? not an exchange... but actually have yours fixed... then you know it isnt welded and such... would that be safe???
I havent heard of this before. I had to have my crank for my 400 machined due to a spun bearing. The guy/machine shop had no problem doing it at all and he builds 600-700hp race engines. My 400 crank was welded and then machined to spec.
Yeah you could do that, but that depends on how bad or worn your stock crank is.. If you can run your fingernail across your journals and not have it get caught, then you can re-use it and have it polished.. But if your nail gets caught then that can't really be polished out, and wouldnt be safe to because of all the material that is gone. I was going to re-use my crank but my journals were too worn to be polished out.. because of low oil pressure
*stupid 2.4's* It would have to be your shops call on whether or not to use your stock crank...
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD
AUTOMATIC!!
328 HP
306 TQ
WHITECAVY(Broken) wrote:Yeah you could do that, but that depends on how bad or worn your stock crank is.. If you can run your fingernail across your journals and not have it get caught, then you can re-use it and have it polished.. But if your nail gets caught then that can't really be polished out, and wouldnt be safe to because of all the material that is gone. I was going to re-use my crank but my journals were too worn to be polished out.. because of low oil pressure *stupid 2.4's* It would have to be your shops call on whether or not to use your stock crank...
Maybe i am mistaken here too... but i thought polishing was just to "freshen up" a otherwise good crank.... and then if it was mildly beat up, you had it machined down and used larger bearings, and then if it was really shot, then they would go so far as to weld it, and re-grind it.
I think mine is beyond a mere polish.... but i dont think it is anywhere near bad enough to need welding.... but what is so aweful about just shaving it down a hair and using oversize bearings? that is how i thought most were done.
I would get a couple opinions on the matter. If what whitecavy said is true....i would rather have a machined crank than a welded rebuilt anyday....
John Benham wrote:I would get a couple opinions on the matter. If what whitecavy said is true....i would rather have a machined crank than a welded rebuilt anyday....
so you coming to summit already??? hows the wife?
and i agree with you. machines with larger bearings sounds WAY better than welded
The wife is ready to pop....still....very ready to pop.
She has put me on a strict no travelling policy....no Summit, no Carlisle, I can go to work still, and the store to buy her odd cravings, but other than that I am grounded until D-day.
I would call your machine shop up and let them know the situation on cranks, maybe they will agree that is best too knowing the situation....Otherwise I would get a couple opinions elsewhere. Perhaps when you contac them they can share some more insight as to the problem they have with machined cranks.
ken soggs wrote:WHITECAVY(Broken) wrote:Yeah you could do that, but that depends on how bad or worn your stock crank is.. If you can run your fingernail across your journals and not have it get caught, then you can re-use it and have it polished.. But if your nail gets caught then that can't really be polished out, and wouldnt be safe to because of all the material that is gone. I was going to re-use my crank but my journals were too worn to be polished out.. because of low oil pressure *stupid 2.4's* It would have to be your shops call on whether or not to use your stock crank...
Maybe i am mistaken here too... but i thought polishing was just to "freshen up" a otherwise good crank.... and then if it was mildly beat up, you had it machined down and used larger bearings, and then if it was really shot, then they would go so far as to weld it, and re-grind it.
I think mine is beyond a mere polish.... but i dont think it is anywhere near bad enough to need welding.... but what is so aweful about just shaving it down a hair and using oversize bearings? that is how i thought most were done.
No your right, thats thats where the whole polising, welding, reusing gets foggy for me as well.. I thought if something needed to be polished down enough, just use oversize bearings.. But im not really sure.. The shop told me, regardless its better to use a crank that hasnt been welded..
Ill find out more info for ya afternoon today.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD
AUTOMATIC!!
328 HP
306 TQ
John Benham wrote:I would get a couple opinions on the matter. If what whitecavy said is true....i would rather have a machined crank than a welded rebuilt anyday....
Just an FYI,
Karo's slowfire has a welded and cut undersize crank in it.
The shop is being rediculous. I would guess that the real reason they say what they do is that they lack the equipment to do any sort of crank work.
Its not all that uncommon. Almost every machine shop in the metro-detroit area sends all their crank work to one of 2 "crank only" machine shop in SE Michigan.
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Todd stole the post from my finger tips. My dad encountered the same thing around here in Iowa a couple years ago. Places like to make you feel incompetent to cover up for their lack of ability. I'd call the shop up one more time just to rake them over the hot coals.
damn sounds like alot of use had this problem. they said the same thing to me. but instead of re-welding the crank i just told them to grind down as much as possiable and just use larger bearings. worked out fine then.
ken soggs wrote:i told them i would like to have my crank polished or machined.... and they cut me off right there and said they would not even work on a car that had a machined or re-worked crank.
this is where i got confused... did you outright TELL them your crank was bad or in NEED of machining?? if so i could see where they are coming from... but if all you would like to do is have it cleaned up and polished i dont see a problem whatsoever.
its like they took what you said out of context, they ASSUMED your crank was shot and in need of repair.
so... DOES your crank need repair or are you just trying to freshen things up?
Riddle me this... riddle me that...
the way it works is if you have spun a bearing then depending on how deep the groove is then they will machine down the journal and you would use larger bearings. to have it polished you need a crank that is in good condition.
DRIVE HARD OR DONT DRIVE AT ALL!!!
I said...
"i appear to have spun at least one rod bearing, and the rest got pretty chewed up.
So i was thinking it would be safest to pull the engine, and go through the typical rebuild process on the bottom end. bore and hone the cylinders, check all surfaces, clean the entire block... polish or grind the crank..."
"We will not use a crank that has been turned or ground, so a new crank would be required if you would like us to perform the rebuild."
What Todd said. They are probably trying to cover up the fact they can't deal with crank work and don't want it to come back on them if what's sent out has an issue.
I personally started with a brand new crank, and then went in another direction after that. GM crank was $800 list. I mostly didn't want to go with an oversize bearing and then after the fact decided to change up the LD9 crank some.
With that said, if all you did was score the bearing journals a tidge you should find a shop that will deal with the crank directly and get it up to spec before you let these guys rebuild for you if needed. It just sounds like they had a bad experience or two and don't want to deal with it.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
I would say machining and oversized bearings, but I would contact a machinge shop with crankshaft capabilities to verify.
It's times like this I wish someone made an affordable 4340 forged crank for our application.
if welding the crank is such a bad idea ....... then what about all the offset ground cranks running in custom stroker combos at the race tracks and on the street .......
it sounds like they are trying to cover theyr ass
sk843143 wrote:if welding the crank is such a bad idea ....... then what about all the offset ground cranks running in custom stroker combos at the race tracks and on the street .......
it sounds like they are trying to cover theyr ass
here is what their responce was when i asked why they wont work on machined cranks....
The reason is that we have been building race engines for over 30 years and we build our race and street engines to the same level of quality. We have found over the years in our applications that using a re-ground crank is asking for problems. Having said that there is a large difference between a crank that needs simply polished and a crank that has been abused so badly that it needs ground.... usually a failed bearing causes quite a bit of damage to the crank. I am sure that many of the people you are talking to would call this over-kill, this is simply the way we build our engines and the way we will continue to build our engines. If there is no new crank available, it really does not give you much of a choice. It is very possible that you will never have a problem in a street application with your re-ground crank.
ok i see the point the shop is trying to make .....
and i also know that welding on a crank is verry touchy
but if you get a good crank shop that specalizes in that then you should b fine just b shure to check the shop out first
sorry about the spelling (busy designing my engine for customs class)
It's too bad there aren't enough LD9 car owners who're willing to pony up for a 4340 forged crank, I spoke to Scat two years ago and they said there wasn't enough demand. However if I could get enough orders they would make them, well I came here to this forum to share the info I was clowned and ridiculed by the members here. IIRC they were going to cost about $650 or so and if you add up the machining cost of welding a crank and having it machined the price would have to be close.
