Has anyone ever run into a shop that said the 7 bolt has structural issues that would cause them to advise against building one up? I got one shop saying "The cranks have some hardness issues due to their nitrating process" and "Beyond the hardening issues 7 bolt rod journals are not as thick as 6bolt and allow less surface area on the rod bearings and are more prone to issues"
so they do not offer a warranty on any 7 bolts they do build up if customer wants to go ahead...
97 Talon with FP 3065-Kelfords-1G race head-DV/DT FMIC-FP 1150's-ECMlink-Meth inj 70/30 at 850cc's
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395161 February 20, 201307:18 pm UTCFebruary 20, 201307:18 pm UTC
stock 7 bolt can handle upto 400WHP. Do you need more than that? I think shop is using "structural issues" as an excuse not to give you warranty to save cash if they f*ck up your build
1996 Eagle Talon TSi AWD 1999 Eclipse GST Automagic 1991 3000GT VR-4
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395162 February 20, 201307:21 pm UTCFebruary 20, 201307:21 pm UTC
stock 7 bolt can handle upto 400WHP. Do you need more than that? I think shop is using "structural issues" as an excuse not to give you warranty to save cash if they f*ck up your build
I have been past that point for a few years now, time to look at 700 as a goal
97 Talon with FP 3065-Kelfords-1G race head-DV/DT FMIC-FP 1150's-ECMlink-Meth inj 70/30 at 850cc's
Re: Building a 7 bolt (98-99) block
[Re: Ghislain Goudreau]
#395184 February 20, 201310:07 pm UTCFebruary 20, 201310:07 pm UTC
Good read here but CW is not my concern at all with this block just the crank coating and the thing about the rod journals, from what I gather having the crank nitrided is my option here.
97 Talon with FP 3065-Kelfords-1G race head-DV/DT FMIC-FP 1150's-ECMlink-Meth inj 70/30 at 850cc's
Re: Building a 7 bolt (98-99) block
[Re: Bryan Lawrence]
#395187 February 20, 201310:13 pm UTCFebruary 20, 201310:13 pm UTC
I'll chime in here I guess. (Long boring post warning)
I'll start off with saying Im no expert, and take my opinions with a grain of salt.
First, I built and machined my 7 bolt for two reasons. First being I already had a 7 bolt to build. Second I wanted to try something different as I had already had 4 6 bolt builds and a few more than that machining favors for friends under my belt.
I'll mention here what I feel are the drawbacks to a 7 bolt, and how I overcame them.
First, oil starvation of the mains, and more importantly the thrust, due to the check valves in the squirters sticking open at low RPM when they should be closed causing premature wear of the thrust caused by design of location. They share the feed to the mains rather than have their own supply from the main galley like 6 bolts.
My solution: Blocked them with 6 mm dowel pins. Its a press fit, and that was done. After three days of reading, searching, and contemplating, I decided they weren't going to cause ill effects by doing so, especially since I am running meth, which will help cool the piston, which is what their function is for anyways.
Secondly, no factory nitriding. To me, this is bad for some reasons, and also I dont think it matters in MOST cases for some reasons.
First why its bad. Nitriding is a HARDNESS process of the surface. It DOES NOT make your crank STRONGER so to speak. Mitsubishi probably didn't do it after the 6 bolts because it was unnecessary for their new improved design. Boy were they wrong. Nitriding or not does not effect the structural "strength" of the crank, and in my opinion, "MAY" even cause it to be weaker. Hardened areas are more brittle and will crack before they bend.
The advantage of a nitrided crank is so when your motor is starving oil, and your bearings begin to wear and touch the crank, its hard enough that it wont disintegrate along with the bearings.
Example, All motors are prone to crank walk. The reason 6 bolts lasted longer, and what leads me to believe there is so much propaganda towards the negative of a 7 bolt, is because 6 bolts had stronger surfaces on the crank that didn't wear as fast as 7 bolts when starved of oil (for long or short periods) and secondly 6 bolts had no crank sensor to get kicked out and be in short a fail safe to get a rebuild like 7 bolts did.
Im not convinced that nit-riding a crank benefits high horsepower motors, but rather is just a fail safe to save your crank when things start to rub, or there is a lack of oil pressure.
When I built my engine, I did something which I find is probably going to be worth while reliability wise and performance wise. I doweled the 7 bolt girdle (which a 6 bolt doesn't have BTW) The girdle is also what attracted me to a 7 bolt. Its sheer beefiness just screams that this bottom end inst twisting. Why is twisting under stress bad? Things begin to touch. See where Im going with this?
So, First I dialed up the block straight on the mill, picked up the center of each main within .0001", and pitched in two very accurate holes for hollow dowels where the main studs go on every main.
Then I did the exact same thing to the girdle. Now I can clamp the girdle tight to the block with ARP hardware, and not worry about the center-lines of the two halves distorting away or getting oval.
I checked. I torqued the girdle down after the doweling, and used a bore gauge to check the ovality of the main bores. All within .0005" roundness. You cant ask for better than that. I also built a split thrust block, so worrying about some slight distortion of the thrust bearings because of torquing the girdle is non existent.
I'm building a stroker 7 bolt as we speak for a spare motor. The only thing I'll do different, is o-ring the block. I wish I would have taken the time to do it to my 2.0L, but oh well.
Another thing I'm going to do, because I'm road coursing this car, is nitride my stroker crank. With all the twists and turns and starts and braking, there is likely to be a little starvation at times because im not that hard core to go dry sump. the extra hardness of the crank should help protect it when times are tough.
Ive had a 6 bolt and a 7 bolt side by side cleaned fresh out of an ultrasonic tank, and had the chance to visually compare the two blocks.
The differences favor the 7 bolt. Less casting flash, more radius's instead of square corners, a big beefy girdle, and less casting flash in the oil return holes to the crank case from the head.
I'll also add, anyone building a 7 bolt, probably doesn't use the OEM rods and pistons, so the size of the rods argument is thrown out. If you are building an OEM 7 bolt, just throw in OEM 6 bolt rods and pistons for the stronger rods.
Again, just my two cents. I believe its all propaganda, and a 7 bolt can be made just as good or better as the strongest 6 bolts have been made with the right approach.
In short, your shop is slightly misinformed, and just watching their back due to the bad rep of the motor for obvious reasons (crank walk)
If you DO nitride you block, make sure you CHECK IT AFTER, cause despite the claim that it doesn't change the size of a journal, it CAN!
Last edited by Rob Cauduro; February 21, 201312:17 am UTC.
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395206 February 21, 201312:27 am UTCFebruary 21, 201312:27 am UTC
Hey we're still steady...slow and steady obviously
That's an obvious difference in thickness. I can't say I've seen the rods and pistons next to each other in a pic before.
Still standing by my 6-bolt's. Although I gotta say, after reading your write up, I'm tempted to go back to 7 and go through the oh wait..that's a waste of money, nevermind I already committed to Ruben's built 6 bolt.
'99 GSX GT35R '03 CBR 600RR
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395235 February 21, 201302:16 am UTCFebruary 21, 201302:16 am UTC
I'm still on the fence about sealing my oil squirter's on my 7bolt, I want to do it for the security but I'm kind of worried about my OEM pistons with 220,000km on em..
Rainbow says I should keep them as long as they pass inspection.
Last edited by Terry Sikora; February 21, 201302:16 am UTC.
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395236 February 21, 201302:33 am UTCFebruary 21, 201302:33 am UTC
Latest email from them after further consultation: This makes me feel better about my decision to build a 7 bolt
Quote
Hi Steve,
Dan does offer some helpful insight here and I want to give him a nod for stepping up and assisting me with your request. The 6 bolt cranks have proven to be the best power holding capable cranks we have come across however, ALL iterations of 7 bolt crank are essentially the same. The Later model 7 bolt blocks are perfectly suited for building IF the oil squirters are removed. Dan is correct, essentially, that we have found the 6 bolt cranks to be of superior strength even to the 7 bolt cranks but the 7 bolt cranks can be used in excess of 1000HP if they have NOT been ground on or modified in any way. Essentially, if you have a split thrust washer engine, it could be built to handle power without crank walk concern but the oil squirters should be deleted to avoid oil pressure loss from a cracked or broken oil squirter which is common on the 98-99 blocks.
Nate
97 Talon with FP 3065-Kelfords-1G race head-DV/DT FMIC-FP 1150's-ECMlink-Meth inj 70/30 at 850cc's
Re: Building a 7 bolt (98-99) block
[Re: Jay Stacey]
#395278 February 21, 201312:54 pm UTCFebruary 21, 201312:54 pm UTC
Is it the squirters themselves, or the check valves? I think someone said they are not that cheap? Maybe in the big picture of an engine build, but they ARE around $100. for the check valves, and around $165. for the check valves WITH the squirters.
"bluebird" worlds fastest scooter ridden by me "Whitebird" RIP
Re: Building a 7 bolt (98-99) block
[Re: Ziggy Dietrich]
#395291 February 21, 201302:14 pm UTCFebruary 21, 201302:14 pm UTC
I think you're thinking of 6 bolt squirters Ziggy. The 7 bolt design is very different from the 6 bolts. As far as I know, the 7 bolt squirter is all one piece (with check valve included), but one of the 7 bolt guys would have to chime in on that.
1995 TSi AWD 11.7@119 1.8 60' - Curse of the Bad Driver PHP: 0
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395296 February 21, 201302:18 pm UTCFebruary 21, 201302:18 pm UTC
Jeremy, you are correct. My mistake. I WAS thinking of the 6 bolt squirters.
They are 6mm in diameter, and about 8mm in length. A 7 bolt squirter presses into the block in a reamed hole.
If I remember correctly, when I priced some out during my build, they were less than 10 bux each?
Id also like to add, if u managed to get one out of the block, chances are its now damaged from pounding on the nozzle part and it will need replacing. There's not really any way to remove them with finesse
Last edited by Rob Cauduro; February 21, 201306:02 pm UTC.
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395319 February 21, 201306:04 pm UTCFebruary 21, 201306:04 pm UTC
What about drilling and tapping for 1g style squiters? EVOs went back to the original 6-bolt style squiters which is what i have used in my 6-bolt block
Never fear a challenge, Amateurs built the Ark, Professionals built the Titanic.
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395320 February 21, 201306:05 pm UTCFebruary 21, 201306:05 pm UTC
Built 7 bolt here as well. I have seen plently 7 bolts making big power, so didn't have any worries about it not being as strong as a 6 bolt.
Couple things I did with my build, have the soft plugs removed from the crank to be sure its 100% clean, crank was then nitrited (magnafluxed, polished, etc), oil squirters were blocked off, ARP mains w/MBCAD dowel kit,(align bore). Oil galleys cleaned up in the block& work done with torque plate.
98 Eclipse GSX DSM82HTA
Re: Building a 7 bolt (98-99) block
[Re: Daren Peacock]
#395382 February 21, 201311:32 pm UTCFebruary 21, 201311:32 pm UTC
I rebuilt my 2g 7 bolt this past spring. I was hoping it was the split thrust version (being a 98 model year) but it seems Mitsu might have used up some of their one piece thrust bearings in the fwds as I've seen other fwd's that should have had the two piece.
I was not aware that there might be a third type of bearing Mitsubishi used. I am pulling an engine from 99 GST Spyder. Is there a chance that I have "one piece thrust bearing"?
1996 Eagle Talon TSi AWD 1999 Eclipse GST Automagic 1991 3000GT VR-4
Re: Building a 7 bolt (98-99) block
[Re: Alex Akachinskiy]
#395422 February 22, 201302:51 am UTCFebruary 22, 201302:51 am UTC
I rebuilt my 2g 7 bolt this past spring. I was hoping it was the split thrust version (being a 98 model year) but it seems Mitsu might have used up some of their one piece thrust bearings in the fwds as I've seen other fwd's that should have had the two piece.
I was not aware that there might be a third type of bearing Mitsubishi used. I am pulling an engine from 99 GST Spyder. Is there a chance that I have "one piece thrust bearing"?
Not a 3rd type of bearing, just the one piece bearing like the earlier 2g's, pre split thrust design. The only other 98+ model year cars that I've come across also posting having the one piece thrust bearing were fwd 98's, probably all early build dates. Based on when they switched to the 2 piece design in the awd's, mine should have been the two piece design, but it was not (engine VIN matches). I would think by 99 model year, your fwd would be the two piece version, but only way to know for sure it too open it up
98 Eclipse GSX DSM82HTA
Re: Building a 7 bolt (98-99) block
[Re: Daren Peacock]
#395475 February 22, 201303:31 pm UTCFebruary 22, 201303:31 pm UTC
Not a 3rd type of bearing, just the one piece bearing like the earlier 2g's, pre split thrust design. The only other 98+ model year cars that I've come across also posting having the one piece thrust bearing were fwd 98's, probably all early build dates. Based on when they switched to the 2 piece design in the awd's, mine should have been the two piece design, but it was not (engine VIN matches). I would think by 99 model year, your fwd would be the two piece version, but only way to know for sure it too open it up
My miss read your post, my mistake.
I compiled a few pics from the web that show difference between split vs none split bearing design. Split thrust bearing (98-99 block):
none split thrust bearing (95-97 block)
Side to Side:
Anyone have better pics please post.
Still few questions unanswered for me: Is there anything different in revised block other than bearings? Can split thrust bearing from revised block be installed into none revised block?
Not sure if this one is true but is 2GB head has better cooling capabilities than 2GA head?
1996 Eagle Talon TSi AWD 1999 Eclipse GST Automagic 1991 3000GT VR-4
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395476 February 22, 201303:48 pm UTCFebruary 22, 201303:48 pm UTC
A Non split thrust consists of two halves, both having the thrust portion on them
A Split thrust consists of one half with only the centrifugal bearing, and the other half containing three pieces, of which two are thrust, and one for centrifugal.
The idea is, when torquing the caps, the two non split thrusts can bind, and miss align, causing premature wear, and if there's a loss of oil pressure, its harder for oil to get in there.
With a split thrust, there's no chance of binding from torquing the girdle, and nothing to align, cause there's only one half existing.
Also, its now easier for the oil to enter the thrust area.
Last edited by Rob Cauduro; February 22, 201305:22 pm UTC.
Re: Building a 7 bolt (98-99) block
[Re: Bryan Lawrence]
#395490 February 22, 201305:12 pm UTCFebruary 22, 201305:12 pm UTC
So only one of the main crank bearings is a thrust bearing?
Correct. Its in the middle. Its funtion is to keep the crank in place from side to side (flywheel to belt sprocket)
It has two functions actually, it also performs in the same manner as the other main bearings do, with the added side portions, hence the name "thrust"
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395495 February 22, 201305:27 pm UTCFebruary 22, 201305:27 pm UTC
blocks are machined differently for both styles of bearings, their not interchangeable.
Thanks for clearing that up.
Originally Posted by Daren Peacock
but it was not (engine VIN matches).
Are you saying based on your VIN number you should have revised but you didn't? Can we use "god sent" CAPS to match-up part numbers between revised and none-revised blocks? I know there is part number for complete short block.
Originally Posted by Daren Peacock
your fwd would be the two piece version, but only way to know for sure it too open it up
I have two motors in my garage with tranny removed. 96 with 230k 99 with 160k. Both motors "click" when I push on flywheel inwards. However, 96 has slightly louder click. It sounds like it has more bearing wear but they are not far apart. Should be able to reuse 96 as is for next season. 99 will sit on engine stand as a spare motor.
Last edited by Alex Akachinskiy; February 22, 201306:47 pm UTC.
1996 Eagle Talon TSi AWD 1999 Eclipse GST Automagic 1991 3000GT VR-4
Re: Building a 7 bolt (98-99) block
[Re: Alex Akachinskiy]
#395507 February 22, 201306:59 pm UTCFebruary 22, 201306:59 pm UTC
Are you saying based on your VIN number you should have revised but you didn't? Can we use "god sent" CAPS to match-up part numbers between revised and none-revised blocks? I know there is part number for complete short block.
No, I just ment the VIN stamped on the motor matches the VIN of the vehicle. I've never checked what version bearings come up with my VIN in CAPS but I guess I could check & see.
Originally Posted by Mike Eng
Originally Posted by Bryan Lawrence
I wish I could just connect my brain to your brain and just download everything!! Thanks for all the info Rob!
+1
THIS!!!!!
Easy now guys, Robs going to start to think he knows what he's talking about
Last edited by Daren Peacock; February 22, 201307:40 pm UTC.
98 Eclipse GSX DSM82HTA
Re: Building a 7 bolt (98-99) block
[Re: Daren Peacock]
#395509 February 22, 201307:44 pm UTCFebruary 22, 201307:44 pm UTC
The best thing you can do to any car to prevent crankwalk is disable that clutch safety switch and never ever sit at a stoplight with the clutch depressed. Personally I don't even put it in gear before it turns green, and so far my unopened 97 7 bolt has made it to 290 000 km without a hint of crankwalk. Sure people will criticize this from a safety standpoint, but if you really try to start your car in gear and not even have your e-brake on, you probably deserve bumping your other car or garage door (and if it's a strangers car hopefully you have the good sense of leaving a note!)
'90 Talon AWD 5spd w/boltons & plugins 11.0@133 - crushed but never forgotten
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395555 February 23, 201312:37 am UTCFebruary 23, 201312:37 am UTC
I think that's the most frustrating part of taking my car for e-test or to a mechanic for any other reason. Every time I get in the car they leave it in gear, and sometimes I forget to check and then just try to start the car and get a nice surprise.
"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
Re: Building a 7 bolt (98-99) block
[Re: Dan Patrasescu]
#395577 February 23, 201304:13 am UTCFebruary 23, 201304:13 am UTC
The best thing you can do to any car to prevent crankwalk is disable that clutch safety switch and never ever sit at a stoplight with the clutch depressed. Personally I don't even put it in gear before it turns green, and so far my unopened 97 7 bolt has made it to 290 000 km without a hint of crankwalk. Sure people will criticize this from a safety standpoint, but if you really try to start your car in gear and not even have your e-brake on, you probably deserve bumping your other car or garage door (and if it's a strangers car hopefully you have the good sense of leaving a note!)
This is why I think it has to do with poor craftsmanship in the build.. Substandard quality. NOT poorly designed oil injectors. If it was poor design.. then There wouldnt be anymore 7 bolts at this time. There are many 2g 7bolts out there that have not been taken care of and are still running strong at high milage. If it was the injectors then they would be all gone!
Yes..Mitsu doesn't exactly have an exemplary QA especially for the timeline when 2G's were being built.
"Mitsubishi Motors admitted today that it had systematically concealed customer complaints about tens of thousands of defective automobiles since 1977.
The admission by Mitsubishi, Japan's No. 4 automaker, came a month after its top executive had denied accusations that it had covered up problems that included faulty fuel tanks, clutches, crankshafts and brakes." By MIKI TANIKAWA Published: August 23, 2000 The New York Times
I'm starting to understand why every old school mechanic's first reaction when I say Mitsubishi is "POS" or a variant of that..but somehow we still love our cars don't we. (I've owned DSM's for 10 years and I can't see myself not owning one)
'90 Talon AWD 5spd w/boltons & plugins 11.0@133 - crushed but never forgotten
Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395609 February 23, 201304:07 pm UTCFebruary 23, 201304:07 pm UTC
The admission by Mitsubishi, Japan's No. 4 automaker, came a month after its top executive had denied accusations that it had covered up problems that included faulty fuel tanks, clutches, crankshafts and brakes." By MIKI TANIKAWA Published: August 23, 2000 The New York Times
I am pretty sure you will find similar complaints if not worst if you study their competitors. I believe that most car owners, who know nothing about physics or how car operates in general, are responsible for making chain of complaints based on nothing at all.
Originally Posted by Dan Patrasescu
Yes..Mitsu doesn't exactly have an exemplary QA especially for the timeline when 2G's were being built.
This is the QA that proves it all.
Originally Posted by Jason Drew
Also, Tim Zimmer's built '99 7 bolt puts to rest any doubts that 7 bolt can't be be build to handle power like a 6 bolt:
1996 Eagle Talon TSi AWD 1999 Eclipse GST Automagic 1991 3000GT VR-4