Update on crankwalk fix

[NosLaser]

I'm going to pretend you didn't say that. I'm going to ask you a simple question. Why do you think things like cylinder heads have torque sequences? Come on man, use your head.

Regards,

 

[1fast97gsx]

yea torque sequences of course .. it might cause a leaky headgasket if they aren't tightned properly but not crankwalk .... crankwalk has nothing to do with headstuds

 

[NosLaser]

Wow. Alright, I'm trying to help you out here without totally flaming you. Do you have any idea what happens when you torque the head down? Hell, let's take your example. Do you know WHY things like leaky head gaskets occur from over-torquing? Dude, seriously. You really don't know what you are talking about. Stop trying to perpetuate an argument, and just sit back and learn something. When you torque the head down for instance, you bet your import ass that the block is seeing movement from the torque. Just like engine harmonics and cylinder pressure will cause your crankshaft to bend and twist under heavy load (this is called crankshaft deflection.) There are a LOT more things affecting a motor than just what you saw on fast and furious. You are so far off the mark in your thinking that I honestly think every word I'm saying is going over your head. Just take this as constructive criticism. Sit back, relax and learn, and stop trying to flex your internet muscles. You are simply digging a bigger hole with everything you say.

Regards,

 

[leet]

Originally posted by 1fast97gsx
yea torque sequences of course .. it might cause a leaky headgasket if they aren't tightned properly but not crankwalk .... crankwalk has nothing to do with headstuds

I'm going to be nice and just tell you to give up.

 

[TSiAWD666]

Seriously, don't waste time with this guy... he thinks he has a general understanding of how the engine is working, but doesn't realize (probably due to either lack of education or real world experience) that the devil's in the details.

 

[doug]

Originally posted by NosLaser
We've performed 'the fix' on several cars down here, and not a single one crankwalked yet, and they are driven daily, and raced constantly.

Aslan,
Who's 'we'? Who down here would I contact if I were interested in having 'the fix' done? PM me if you prefer.

 

[90AWDRaleigh]

Originally posted by BatmanGSX
There are very few people in the world that can properly, beyond all question, assemble a DSM bottom end. Unfortunately most of those people are robots on an assembly line in Japan.

Assembling a bottom-end is NOT rocket-science. What's the difference between assembling the bottom end of a Honda/Toyota/Mazda/Cheverolet....and a DSM? NOTHING, both you measure clearances. I believe what a majority of people overlook is the importance of getting the block align-honed, making sure all of the bearing caps/block are perfectly straight. Again, there is NOTHING that makes assembling a DSM's bottom end different from assembling 99% of other manufacturer's bottom ends.

Mike

 

[95tsi_canadian]

How many people here have had their blocks bored without a deckplate torqued on along with the bellhousing?

 

[Puller]

good call, might as well hold it in ur hands while it's being bored. same thing if you don't.

 

[Groomz]

Originally posted by 95tsi_canadian
How many people here have had their blocks bored without a deckplate torqued on along with the bellhousing?

JWT attaches the bellhousing and accessories to SR20DET blocks to avoid distortion from bolting on the parts after the boring process.

 

[95tsi_canadian]

Here is another one

How many of you installed ARP studs after the bottom end was finished? I have talked to a few guys that put in head studs cuz they wanna boost big and like the studs for their great torque. Yes they hold more than the torque to yield stock bolts, but I would bet that you're changing how block geometry.

 

[1fast97gsx]

ok I am asking a 100% serious question here:

My motor is stripped down as far as can go right now as it is going to the machine shop for boring / honing and a few other things. I have Ross pistons and eagle rods along with all new bearings. I'm just wondering when I reassemble everything should I bolt the head on ( since I have no torque plate ) to the right specs and then put the crank and main studs back in? Then take the head back off and reinstall the pistons and rods along with bearings ... and then reinstall the head once again only this time with the ARPs? Before this thread I assuming jsut put the bottom end back together completely then put the head back on for the first time. Would it help doing it one way over the other or not at all? Thanks.

 

[NitrousBob]

I want to know after you machine your thrust bearing surface how you have less of a chance for walk when you just opened up the clearances. I think the stud outer dowel is a great fix. Someone didn't even read that they were installed just like the cam dowels and some how those roller cams don't walk. They are not simply spacers. go figure. Oh one more thing the pressure on the flywheel is pushing not pulling. The throwout bearing pushes on the fingers of the pressure plate to release it. Thats probably when you would have the most pressure on the flywheel/crank. When its released the pressure plate has a force but the clutch disc just gets pulled across the splines. Not much to push a clutch across some splines... Its not yanking the crank towards the tranny.

 

[pinknuggit]

I thought i'd chime in my experiences here.
Every engine i've ever built, I will always torque the heads/head down fully before installing the bottom end. That's the way I learned.
But I remember in '97 when my dad ordered a brand new dodge ram, that the chrysler employees went on strike. His truck was halfway through the assembly line while they were on strike too. His interior has mismatched colors and has the wrong transmission.

 

[gixxer]

i just want to say thank you to NosLaser for making this information available, it was a very interesting read and seems to be very plausable. the way you approached and explained the problem was very logical and i appreciate the lack of misinformation. maybe you *should* be an engineer

-joe

 

[DSMJim]

Actually here's a simple yet VERY interesting theory. The 2gs and 1gs get oil for the turbo from different locations. I point that out because here's the theory. Have you noticed that when you upgrade a turbo on a 2g you almost always go w/ a ss oil feed line. That feed line replaces the stock fitting on the oil cooler, BUT that stock fitting is needed for proper oil pressure to the motor. Before you say BS, take a look at the inside of the stock oil line 19mm fitting on the oil cooler. There is a very small orifice that regulates flow/pressure to the turbo. Now take a look at any ss oil feed line kit on the market. That orifice is missing. A ss oil line will allow your turbo to get much more pressure and flow, but the problem comes from the fact that there is a trade off. The oil pressure at idle and low rpm is now reduced to the motor. If you don't believe it, hook up an oil gauge and switch the stock oil feed line to a ss and watch the difference in pressure. Now, this decrease in oil pressure may or may not be the cause of walk, but it would only take a poll to find out. If alot of people have walked and are using ss oil feed lines, then we perhaps can begin to draw a correlation.

I wanted to reply to this before but didn't so maybe now I will throw my 0.02 in..

This is an interesting theory however it's incorrect. If you look at the size of the hole in the restrictor you will notice that it's exactly the same size as the inside of -3 hose that is commonly used on a SS feed hose for a turbo. The hose its self becomes the restrictor and does not allow any more pressure though the line than there was normally before. Even if you went upto -4 its only about 15% larger, however still VERY small and will not affect the idle oil pressure.

I have an oil gauge and did not notice any change in my pressure switching to an SS line so your theory doesn't hold water. Besides at idle a motor doesn't need very much lubrication and 15-20psi of oil pressure is plenty for idle.

 

[90LaZeRrst]

im very down with getting this done. I got a motor for free from a friend with all after market parts but needed new bearings. I was told there are new bearings called H rated bearings just for the 7 bolt crank. I am going to get noslasers procedure done and i want to get these bearings. I need to know any information on these if anyone has some. Shoot me a pm or talk to me on jclp69 - aol thanks

 

[StarDiamond]

IDK much about engines but we do have a race car w/ a 350 Chevy small block. One thing my dad always got was a block w/ 2 extra main bolts. When u refer to 6 and 7 bolt engines I am assuming this is what u mean. I know for example idk if I am correct on this but Chevy makes an 8 and a 10 I think main engine. Guess what every NASCAR team uses the 10. IDK why everyone seems to jump boats fast but the 6 bolt in theory shouldn't the 7 bolt be better? Great article and also if really wanted to get technical w/ his dowel pins when u also move them around u end up w/ different squish patterns for the cylinder heads. I use to race go-karts and we always would dowel are cylinders to are heads for alignment idk but all his shit makes sense.

 

[gixxer]

err buddy you aint even close, time to read the vfaq

 

[NosLaser]

StarDiamond, we are referring to the number of flywheel bolts. The common Chevy motor is a '4 bolt main' which refers to 4 bolts being used on the main caps; completely different area of the motor.

NitrousBob,

Even during a standard align-hone you have to use oversize main bearings. Same concept here except the align-hone process is being performed with the proper torque on the deck of the block, as well as the proper torque on the now perfectly aligned main girdle. Now that you have everything straight and lined up properly, you can get a 'true' machining done on the main journals without worrying about the tweaking out of shape once torque is applied, thus throwing thrust bearing alignment out of whack.

Gixxer,

Thanks for the compliments.

Regards,

 

[Defiant]

I think the stud outer dowel is a great fix. Someone didn't even read that they were installed just like the cam dowels and some how those roller cams don't walk.

Chalk and cheese. Camshafts have relatively no mass (compared to the crank and bottom-end bits), and aren't subjected to axial loading.

 

[ItsStockOfficer]

I will say that the theory holds water in my book. Crankwalk is not a magical phenomena. It obviously has causes rooted in misalignment or oil starvation.

Step 1: Have an oil pressure guage to make sure pressure remains adequete.

Step 2: Build the engine in such a way that all possible guess work is taken out of where the crank will be after everything is done and torqued. Makes sure it is done with complete precision, so that specs when machined = specs when assembeled. Use the superior 98-99 bearing if you can.

Sean

 

[Strm Trpr]

^^^ Indeed, if my 7-Bolt takes a walk, I'm going to find a shop that will do exactly what NosLaser's post said to do....

BTW, I did check my crankshaft endplay with a feeler gauge when I did my BSE, and it was right at .0071", that is the spec limit that Mitsu states in their service manual....
I also checked it with a magnetic base dial indicator pointing on the dampener pulley to validate it, and sure enough .0071" (Fingers Crossed)
.009" is the service limit.

 

[Defiant]

I will say that the theory holds water in my book. Crankwalk is not a magical phenomena. It obviously has causes rooted in misalignment or oil starvation.

Ah, but what if the misalignment is from the phenomenon of the block being made just that much too light? What if it's from them taking just 1/64" too much out of the main bearing and skirt webbing in the area of the center main?

I'm still waiting for a cw theory that fits all the way.

 

[NosLaser]

Ah, but what if the misalignment is from the phenomenon of the block being made just that much too light? What if it's from them taking just 1/64" too much out of the main bearing and skirt webbing in the area of the center main?

The way around that is the fact the the block is being machined with all the torque it's ever going to see already applied to it. Keep in mid the type of torque applied from bolting the head down and bolting the main girdle down is different from the kind of torque it sees from being spun to 9K rpm. The fact that material is being taken away in really inconsequential in this instance.

Regards,