7 bolt build is it worth it?

[chasedardis]

First of off this is not a crankwalk walk bashing so saying that. I have a extra 7bolt (92k) block and head nothing wrong just took out to put a 6 bolt in my gst. I checked crank its in spec so that's good. I building a 99 gs 420a to sell got I really good deal (400) for the car just in about a thousand pieces though so im already planning my next build. I want to build a 2g awd next my question is do I go with the 7 bolt or find a six bolt I can save a good amount of money if I use the 7 bolt. My goal is 450 whp daily summer driver. Im just tring to get some input and advice

 

[99eclipse420]

I would stick with 7 bolt if there are no issues with it. No point in trying to find a 6 bolt and paying for it, might as well save your self 300-600 bucks.

 

['97boostinGST]

I built my 7-bolt.
Love it.

Question, are you planning on putting the built motor on a GS chasis?
Or am I missiing something?

 

[hazmat6135]

after the OE bearings are replaced and a machine shop checks your spec there shouldnt be any crankwalk worries. build the 7bolt

 

[DSM1G90]

One can build up a very NASTY 7bolt motor!

 

[Rajin]

Yeah, I'm still back and forth on my build as well.

 

[95talongirl]

Agreed. Use the 7-bolt. Had mine gone through at a machine shop to make sure it was all good to go.

 

[99gst_racer]

If it's the split thrust bearing 7-bolt, then build it up. I personally wouldn't sink money into a 1-pc thrust 7-bolt.

 

[IQ685]

not trying to noob this thread up, but can someone tell me how you pull off a 1 piece thrust bearing? Did the just put a thrust bearing on the top or the bottom main? Thanks for the answers, and if anyone has a link to a better explanation it'd save you quite an amout of typing trying to explain it.

 

[turbodude]

I have a 7 bolt myself and am in the process of building it up, though my car only has 74k so i don't see the point in swapping to a 6-bolt right now since my engine still is pretty fresh so to speak.

 

[99gst_racer]

7-bolt thrust differences

 

[DSM1G90]

Question? Why wouldn't one want to build up the prior motor - couldn't one use the three piece bearings on that earlier motor?

Maybe this will be a good guideline to share for DSM owners who have the earlier motor.

 

[99gst_racer]

The bearing designs aren't interchangeable. There were also some small machining differences to the block that came along with the 3-pc bearing. I can't remember the specifics, but I do know that you need to run the appropriate thrust bearing for the specific block that you have.

 

[tkrPerformance]

I built a 94 galant gs 2.4 for my evo 3

 

[russell3123]

i ran a 60mm turbo at 28psi on a stock 1 piece 7 bolt with 76k miles for 3 years and never had a problem.. its usually the clutch that kills them . on a gst u should be fine since u wont need anything over a 2100 pressure plate unless u plan on running slicks

sry scratch what i said, just realized u want to build an awd 2g

 

[99gst_racer]

i ran a 60mm turbo at 28psi on a stock 1 piece 7 bolt with 76k miles for 3 years and never had a problem.. its usually the clutch that kills them . on a gst u should be fine since u wont need anything over a 2100 pressure plate unless u plan on running slicks

I don't know about you, but I'd be pissed if the thrust bearing design of my built engine limited me to which clutch assemblies I could run to put the power to the ground.

 

[IQ685]

ah, I see thanks for the info, so if our block uses the 1 piece thrust bearing, is it necessarily doomed to crank walk, or if it has aftermarket thrust bearings and the block and crank have been machined is it possible that we're safe? I ask because I just took the '98 7 bolt out of my car and was going to have it machined out to .020 over and rehoned, but when I asked the guy about it, he said that he had a complete 7 bolt bottom end that had a .020 overbore sitting in his shop from a car he bought and parted out, which is now in my car and I believe that it's of an earlier design than mine. This bottom end that he sold me is completely fresh, new cross hatching and all, so it has been rebuilt and I'm assuming machined. I'm just trying to figure out if I my be in for more repairs in the way of CW later on.

 

[TSITurbo95]

No. It just has a better chance of crank walking. It may never happen, it may, its just a waiting game. Any car can crank walk. It is over rated, so just don't worry too much about it.

 

[Alex7747]

If it's the split thrust bearing 7-bolt, then build it up. I personally wouldn't sink money into a 1-pc thrust 7-bolt.

are you sure its the bearing design itself? because i see plenty of engines with the same design thrust bearing as the early 2g 7 bolt and they dont crankwalk. i'm thinking it has more to do with poor lubrication to the thrust bearing. in other words i'm thinking the main cause to the thrust bearing failure would have to the the oil pumps itself of the bad oil choices (weight of oil).

when i drive my car kind of hard and it gets hot the oil pressure drops to about 3-4 psi(1500 or so) and thats what worries me. at cool start up the oil pressure at idle is about 50psi. (i know while the difference in oil pressure, im not asking that).

also the earlier 7 bolts(1gb) never really had a problem with crankwalk. im not really sure positive what the thrust bearing design on the later 1gs were but im pretty sure it was a single piece design..mabe the just had a better oil pump design?

or maybe its just a combination of all those that cause crankwalk in the earlier 2gs. crank out of spec, bearings out of spec, poor lubrication(low oil pressure) once hot, and heavy clutches..

 

[99gst_racer]

so if our block uses the 1 piece thrust bearing, is it necessarily doomed to crank walk

No, it's never garunteed to be doomed. Just more prone for crank end play. And there's no way to fix that other than starting over with a new block and crank. Which is why I wouldn't invest money into an early 7-bolt.

If your '98 engine is a 3-pc thrust block, then I'd personally use it over his (assuming his is an early 7-bolt).

 

[russell3123]

doesnt really limit you , the stronger the pressure plate is the more force on the crank due to the clutch not slipping on launches. just try to slip it a little on a launch and should be fine

 

[IQ685]

If your '98 engine is a 3-pc thrust block, then I'd personally use it over his (assuming his is an early 7-bolt).

Well, the bolt that holds the intermediate shat to the back of the '98 block is snapped off and I did a pretty good numer on the bolt trying to get it out without taking the engine itself out, in any case it's a little too late to go back now(the enigne is already assembled and installed in the car. I still have the '98 block, crank, and main girdle and yes it is a 3 piece thrust bearing block, I remember the 2 thrust bearing shells when I removed the crank. so if this block walks I'll work on getting the intermediate shaft bolt out of the'98 block and build it(probably over OE spec).

 

[99gst_racer]

are you sure its the bearing design itself? because i see plenty of engines with the same design thrust bearing as the early 2g 7 bolt and they dont crankwalk. i'm thinking it has more to do with poor lubrication to the thrust bearing. in other words i'm thinking the main cause to the thrust bearing failure would have to the the oil pumps itself of the bad oil choices (weight of oil).

Right, it has little to do with the bearing design. I just mention the bearing design because that's the easiest way to distinguish between the two 2G 7-bolt block.

There's a handful of different theorys as to why the early 7-bolts developed excessive play, but there's no doubt that the early blocks were far more prone to endplay than the later blocks.

 

[2gGst98]

You guys shuld read this it makes alot of seince. It is a way to better help and near eliminate the CW problem.
Thrust bearing modification (crankwalk prevention)
By sschambers
http://www.dsmtuners.com/forums/cyl...earing-modification-crankwalk-prevention.html


I dont know how to make it be able to click it but search it, it shuld come up. I dont remember if it was specificly for the 2Gb or 2Ga, it may be for both.

 

[chasedardis]

Well im still undecided I need a good machine shop if anyone knows of one around northeast ohio let me know. For the record im almost done with it runs just need body work and paint then im selling it too fund a gsx build which the 7 bolt will be used for. I also have to check the thrust bearing wether its 3 piece or not. Thankx for the input.