Building a 7 bolt (98-99) block
#395160
February 20, 2013 06:59 pm UTC
February 20, 2013 06:59 pm UTC
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Posts: 628 Kingston, Ont
Steve White
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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
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395162
February 20, 2013 07:21 pm UTC
February 20, 2013 07:21 pm UTC
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Bryan Lawrence
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"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395170
February 20, 2013 08:23 pm UTC
February 20, 2013 08:23 pm UTC
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Bryan Lawrence
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That's a good point, we actually had a chat not long ago about 7 bolts, and Rob brought up some good point. let me see if I can dig it up. It was another thread but I did find this one: http://www.ca.dsm.org/forums/ubbthreads.php?ubb=showflat&Number=363919
"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395179
February 20, 2013 09:17 pm UTC
February 20, 2013 09:17 pm UTC
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Ghislain Goudreau
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Welcome back Steve.
I know an excellent machinist in Belleville if that might help.
Ghislain
Rouge!!!
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Re: Building a 7 bolt (98-99) block
[Re: Alex Akachinskiy]
#395183
February 20, 2013 10:06 pm UTC
February 20, 2013 10:06 pm UTC
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Steve White
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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
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395185
February 20, 2013 10:11 pm UTC
February 20, 2013 10:11 pm UTC
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Steve White
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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
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395191
February 20, 2013 10:38 pm UTC
February 20, 2013 10:38 pm UTC
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Joined: Oct 2010
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Bryan Lawrence
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With numbers like 700hp you should probably be looking into a forged crank. This is what I have been refering to when trying to decide what to use for my build. https://docs.google.com/spreadsheet...tYW5BMFlSeFdGUTFEOXBxaVE&usp=sharing
"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395200
February 20, 2013 11:47 pm UTC
February 20, 2013 11:47 pm UTC
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Joined: Mar 2003
Posts: 5,126 Toronto
Rob Cauduro
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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, 2013 12:17 am UTC.
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395220
February 21, 2013 01:13 am UTC
February 21, 2013 01:13 am UTC
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Joined: Oct 2010
Posts: 9,968 Caledon, Ontario, Canada
Bryan Lawrence
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For all the people that tried to open the file I linked I have changed it to anyone with the link can open it now. https://docs.google.com/spreadsheet...tYW5BMFlSeFdGUTFEOXBxaVE&usp=sharing
"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395228
February 21, 2013 01:26 am UTC
February 21, 2013 01:26 am UTC
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Joined: Apr 2010
Posts: 6,809 Ottawa, ON
Mike Eng
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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
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395241
February 21, 2013 03:09 am UTC
February 21, 2013 03:09 am UTC
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Joined: Oct 2010
Posts: 9,968 Caledon, Ontario, Canada
Bryan Lawrence
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As shown in my spreadsheet, if you want to be safe for the 400 range you can go with the 1g rods and 2g pistons. LOL Alex, I see you started pulling apart one of your cars and have changed your signature to indicate this
"Old Blue" 91 Talon TSi AWD "Super Enthusiast" 91 Talon TSi AWD Checkout DSMFAQ.com!
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395270
February 21, 2013 08:37 am UTC
February 21, 2013 08:37 am UTC
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Ghislain Goudreau
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One more adventage to 7 Bolts is lighter reciproccating mass which should be good for a Corner Carver kind of Sled.
Some have rebuilded 7 Bolts using OE Parts with excellent results.
Keep us posted Steve.
Rouge!!!
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395276
February 21, 2013 12:12 pm UTC
February 21, 2013 12:12 pm UTC
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Posts: 628 Kingston, Ont
Steve White
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Latest email from them after further consultation: This makes me feel better about my decision to build a 7 bolt 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
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Re: Building a 7 bolt (98-99) block
[Re: Steve White]
#395290
February 21, 2013 02:09 pm UTC
February 21, 2013 02:09 pm UTC
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Posts: 7,263 Niagara Falls, Ontario
Ziggy Dietrich
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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.
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