So I am getting ready to do a complete motor build. Have a couple questions.

First off what is the difference between the stock main studs and ottp's main studs and which do you guys recommend? Are the stock main studs capable of 400hp without any issue? Is it that they are just not re-usable?

Next up what are your guys thoughts about using stock rods, and or cryo treating them. I don't really want to drop just a grand on rods right now for a 400hp build, however whenever something happens to this build and its time to do another, I would be upgrading them.

Next is compression. I want to run a higher compression to make more power, however I don't know what the darton sleeves can handle and what is safe/unsafe. Any thoughts/opinions? I would like to run 11:1 with a tvs and 2.7 pulley on e85. Will higher compression pistons mean I need more/less fuel or does that not change with compression?

As far as the crankshaft, what do you guys recommend doing to it? I hear a lot of different terms, micropolishing, butchering, knife edge, etc. What do they mean and what should I do?


Last but not least, cryo treating. Has anyone cryo treated stock rods, or the stock crank, is it worth it? I want to do this build the right way so if that means spending more so be it, but I don't want to waste money if it's not necessary.

Currently the build looks like this.
Darton Sleeves, Diamond forged pistons *unknown compression*, arp head studs, stock main studs *or ottp's not sure the difference*, Cometic head gasket, neutral balance shafts, ported head, 78lb valve springs, possibly upgraded valves not sure yet, oh ya and the hardened oil pump gear. Anything im forgetting besides gaskets and seals?

Thanks for the help guys.

 

stick with stock head gasket ive heard some bad story with the cometic gasket

 

can't help you with everything, but...

 

the cometic head gasket is ok if the head and block are honed or milled to be perfectly smooth.. if not.. use the oem head gasket.. itll react better to a surface that isnt perfectly laser cut smooth essentially

 

exsoccer - I was talking about main studs, not head studs. Obviously the head studs will be replaced with arp's, but I am talking about the main studs, the studs that are down by the girdle/crank, theres like 20 of them. It's 65 dollars vs 420 dollars and I just don't know if ottp's are worth it or not. Is this a "stressed" area? If it's something important I will grab them for sure, however if it's just the fact that stock are not re-usable then I will go with stock 6 times before meeting ottp's price and I doubt I will build it 6 times. Thanks again for the info that you gave me, I appreciate it. I will be going with the cometic gasket because both surfaces, the head and block will be machined.

 

sorry, even after reading it then quoting and reading what i typed i didn't catch the main studs. hahah.

basically the same principle though if i remember right. its been a while since i've done engine work on anything

 

No worries man its late lol. I assumed the same concept applied I just didn't know how critical these bolts were. For example if the timing chain cover bolts were 20 bucks stock or 120 bucks for upgraded ones, i would still buy stock ones because they aren't a bolt that see's any stress, know what I mean? It's just a really big price difference between the two, thats why its got me thinking. Hell its basically half the price of rods just for 20 bolts lol.

 

on my motor i'm using stock main bolts, just like you said, there's ******* 20 of them lol

the cryo would help, on my 7mgte motor i had the used rods cryo'd, they had 125k on them and i ran it right up to 550whp a few years ago and now someone in new jersey has the same motor on a bigger turbo and it's still going strong. I would do this, but i did speak with someone from eagle rods and they are working on some lsj rods right now, last i heard was that they were being machined but not distributed yet (and that was right from eagle not a third party). usually eagle are around $400 a set for 4 bangers.

the darton and house brand that ottp sells can be bored out to .100 over and still hold iirc 600-800hp, so on a stock or .5-1mm overbore, it should hold 800+

as for the compression, i wouldn't run more than stock personally. when you go up in cr, your heat goes up and your timing goes down. you'll be better off with a 9.5:1 and getting the air out of the motor faster with a nice set of cams and timing it properly. i think someone on th eboard already tried this and went back down to a lower cr but can't remember who it was

 

main studs are worth but you have to have the mains line honed before you can use them
the mains are a super high stress area
cometic hg work just fine if you read and follow the directions
compression 10.5 is plenty when you incease compression you increase the engines efficancy and ofcourse you need octane to run it
darton sleeves will handle the stress just fine
rods are plenty beefy to do the job
as for the crank if you lighten it up it will spin up faster micro ploishing isent that expensive and will reduce friction and help the engine make more efficiant power
and if you want to make over 400 hp reliable youll need to get cams and adj cam gears and degree the cams in so the events happen when they are supposed to
we do have great cams for stock but with a blower they are only good to around 370 to 380 hp u just run out of cam at that point
get a ported head exh only
valve springs are going to be a must and i would also go with a solid lash adjuster are hyd lash adjusters wont handle the abuse long with higher lift cams and increased spring pressure
ask me how i know

 

so exactly what of that stuff have you done that would validate your assumptions?

only thing i remember you doing is changing the read out on your speedo to use kmh and you tried to lie to us and tell us you had a massive amount of work done to your car.

 

well you have me confused with someone else

ive been building cars/engines for along time so its experience speaking not just assumptions

 

ok my bad, there was some other douche from ky, i'll track down that thread..

anyways, i have to disagree with your higher cr. all cars are different and there has already been one on here try it and went back to lower with more timing and made more power

found that thing... it was some dude named jrod, sorry about that lol

https://www.cobaltss.net/forums/show...t=hptuners+kmh

 

if you have the fuel to support the higher compression its a win win e85 or race fuel if you dont have the fuel you wont be able to get the benifit of the higher compression there is one guy on here running a 2.5 pully on his m62 and 10.5 pistons with meth and is making over 300 he has a very nice setup

 

cryo everything, i did, my motor has seen upwards of 50lb/min of airflow held just fine. cometic HG is iffy depending on who you talk too.

 

Thanks for the input guys. It looks like the rods are going to be cryo'd.

I still haven't decided on ottp main studs or stock main studs. What I am wondering is if stock main studs have broke, or are breaking, on higher hp motors?

I have a good friend that has a built motor running 10.5:1 cr forged pistons and he isn't having any issues. I planned on running the same, on both e85 and 93. I would have two tunes obviously, one for extremely high power/timing on e85 and the other as a mild daily driving 91/93 tune.

Only thing I really have left to decide at this point is the compression and whether or not I should go with stock main studs or ottp's. What are your thoughts guys?

I have seen a m62 car with 10.5:1 compression put 2 cars on a 300whp TVS 2.9 93octane 17 degree timing car. I think these cars when built correctly like the higher timing, but I haven't seen a lot of people do it. All I know is this motor is pretty impressive and I wouldn't mind building mine similar to it.

 

if your gonna do it then do it i would do the main studs

 

Can someone verify that the ottp main studs are re-usable? Or can someone verify that they are stronger then stock?

I would like a comment from sean/josh, I pm'd them but if someone else has something to add then by all means feel free

I will also be documenting the prices for all of the machining etc and what it costs for everything to be installed etc.

 

i wouldn't waste your time with that, prices are completely different for every shop... there's nothing even remotely similar between machine shops

 

well they arent ottp studs they are arp and yes they are stronger then stock and yes they are reusable

 

I don't know if this is exactly true. Sean is looking into it more for me. I don't believe they are ARP main studs otherwise he would have known that I'm sure and they would be listed as ARP with an ARP box. He said he "doesnt think" they are TTY *torque to yield* which means they are probably re-usable but hes looking into it now. He said he also said he "thinks" they are 1/2inch and stronger but he is checking into this also. Once I have more information on them I will share with the rest of the class

 

well ottp dosent make studs so they are either golden eagle or arp and they arent goint to be tty if they were there would be no point in using them they would be as weak as the bolts

 

Right, I highly doubt they are TTY but just want to make sure from the vendor first and find out what they actually are. If they are ARP that would be great, but as long as they aren't just like....cheap true value / ace hardware aka go into any hardware store and find something that will work type of thing, I will be happy lol.

 

i highly doubt it ace aint the place for this ****

 

@ $21 each it better be the most expensive material arp can use for a bolt

 

self - I know what you mean. You can get 6 stock kits for the price of them, is it really worth it? Granted, if it's a stronger bolt, maybe it is. But I doubt I will take them off more then 6 times lol.