Rusty 2.4 Blocks

StarquestRescue · Post by **StarquestRescue** » Sun Mar 30, 2008 8:46 pm

I found 2 van engines of the right era but the heads are gone and the bore and deck are very rusty from condensation. I don't think they were rained on being in vans.

Turbo pistons seem to only be available in .020 over. Why is that? I am not sure that would be enough to clean then up. Could be a challenge to get the pistons out.

One has all the accessory. Cost would be about $200 including expenses. Should i take a chance.

77amc · Post by **77amc** » Thu May 01, 2008 12:56 am

I just got some Turbo eclipse/talon pistons off of Ebay for about 90 bucks and there coated top of the ring lands.
I think their add stated up to a .75mm oversize.. NOT sure, I'd have to look back. Email me so I can send the link to ya.
That's what I'm using in my 2.0 max block.
You could always soak it in Miuratic acid OR lime-a-way for a while to remove ANY rust and tehn look for pits in the bores.

My 2 cents.

Errol

jeffball610 · Post by **jeffball610** » Fri May 02, 2008 7:29 pm

$200 for a rusty engine?! I'd pass on that. I can get a short block for $75 from the yard. Hell I sold a 2.4L for $150 a while back that was in perfect shape. Also, if you're looking for 2.4L engines, stick with the 7-bolt types. The 6-bolt does not have the main cap bracing that is part of the turbo engines.

Robert Venable · Post by **Robert Venable** » Wed May 07, 2008 10:53 pm

jeffball610 wrote: Also, if you're looking for 2.4L engines, stick with the 7-bolt types. The 6-bolt does not have the main cap bracing that is part of the turbo engines.

So, you would trade "crank walk" to have little extra bracing on an already overbuilt bottom end?? Why not just add a girdle to the bottom end to stiffen it up if you are really that worried about it?

jeffball610 · Post by **jeffball610** » Wed May 14, 2008 11:28 am

Crank walk is still a mystery. I know many people running high pressure clutches on stock 7 bolt bottom ends. The issue mostly seems to come from the piston oil squirters, but there is an issue with the thrust bearing as well. This can be resolved, and there are companies offering solutions. They seem more like witch doctors in some cases, but do offer solutions. Jack of Jack's Transmissions here in Colorado offers a no walk garauntee with his fix and can perfrom it on motors that have already walked while still in the car. He won't devulge his secret, but he has had great success with it. I don't believe the NA motors have squirters and thus eliminates one possible cause.

By the way, you can walk a 6 bolt motor, so don't use that as an excuse. The 7 bolt crank is also stronger than the 6 bolt even though it is not nitride treated from the factory. The 7 bolt rods are not as strog, but you're going to build that bottom end anyway, so who cares. Even if you don't build it, the NA 7 bolt can take some boost, although I'm not sure how reliably. I've seen good 13sec passes on a stock NA bottom end here at altitude. Lower elevation guys will have issues due to the increased compression, but it can be done.

So, why should we not use the 7 bolt 2.4L engines?

Robert Venable · Post by **Robert Venable** » Wed May 14, 2008 10:31 pm

double post

Robert Venable · Post by **Robert Venable** » Wed May 14, 2008 10:32 pm

jeffball610 wrote:Crank walk is still a mystery. I know many people running high pressure clutches on stock 7 bolt bottom ends. The issue mostly seems to come from the piston oil squirters, but there is an issue with the thrust bearing as well. This can be resolved, and there are companies offering solutions. They seem more like witch doctors in some cases, but do offer solutions. Jack of Jack's Transmissions here in Colorado offers a no walk garauntee with his fix and can perfrom it on motors that have already walked while still in the car. He won't devulge his secret, but he has had great success with it. I don't believe the NA motors have squirters and thus eliminates one possible cause.?

Crank walk IS caused due to excessive wear on the thrust bearing. What causes this unusual wear has not been confirmed, but it would seem to me that lack of oil pres. to the thrust bearing would cause this. What would cause that lack of oil pres. could be the squirters (which only turbo models have, as far as I know), or I've also heard that the main bearing oil circuit (which is different on the 7 bolts) could also be the cause of this.

jeffball610 wrote:By the way, you can walk a 6 bolt motor, so don't use that as an excuse. The 7 bolt crank is also stronger than the 6 bolt even though it is not nitride treated from the factory. The 7 bolt rods are not as strog, but you're going to build that bottom end anyway, so who cares. Even if you don't build it, the NA 7 bolt can take some boost, although I'm not sure how reliably. I've seen good 13sec passes on a stock NA bottom end here at altitude. Lower elevation guys will have issues due to the increased compression, but it can be done.

You can "walk" any motor, but the 7 bolts are known to have more issues with this than any other motor I have heard of. Would you disagree? How is the 7 bolt crank stronger? And even if it is, when have you heard of a crankshaft failure on a 6 bolt? If the 7 bolt is just as good, if not better than the 6 bolt, then why is it that so many people swap from 7 bolt to 6 bolt motors, but never (In my experience) the other way around??

jeffball610 wrote:So, why should we not use the 7 bolt 2.4L engines?

To each, his own. For me, it's gonna be a 6 bolt 2.4 because that is what I have. It was also the way buddy of mine went with his 11.12 second AWD 2nd Gen Eclipse. This is after he went with a stage 3 Magnus 6 bolt. I was given his entire long block, which I plan on using the 2G head for the smaller ports. The 7bolt 2.0 bottom end is simply a holding fixture for the head to me.

jeffball610 · Post by **jeffball610** » Fri May 16, 2008 2:47 pm

The 6 bolt crank fails at the #4 fillet at high power. Usually this isn't until 600hp or so, but is still a failing point.

Yes the 7-bolt is known for crank-walk and people even developed the term for it. However, why have the EVO 8-9 motors not shown this failure. I'm not too educated on the EVO motor, but know that is an extension of the 7-bolt design. An evolution of it. I like to think that crank walk occurs because of poor quality control and the oddness of the crank bearings. (along with everything else I listed above) You need to find out what size each bearing is for each spot. They are not all the same size as in most motors out there.

Also, there is distortion of the block from the head studs (or bolts) that reaches all the way to the crank mains. The factory procedure is to torque the head and then the mains. Sounds weird to me, but that's how Mitsu did it. Also, I don't believe the 2G motor was even designed by Mitsubishi. I know they were built in the US and the 6-bolts were all assembled in Japan. Maybe there's something to that.

A lot of people have swapped out the 7-bolt motor in fear of crank walk, and some have done it cause JDM engines could be found fairly cheap and easier than rebuilding the one they had. Everyone has their opinions on which motor is better and most of it comes down to their experiences with each type.

I for one have a 7-bolt 2G bottom end (8.5:1 pistons) and a 1G head. Yeah the 2G headis a better design, but the 1G flows more stock and is cheaper for me to get. Everyone has their reasons, and those are mine. Anyone reading these posts can make their own decisions. I'm not one to tell you what you should do, only add my opinion and advice from my own experiences.

Robert Venable · Post by **Robert Venable** » Fri May 16, 2008 8:32 pm

jeffball610 wrote:The 6 bolt crank fails at the #4 fillet at high power. Usually this isn't until 600hp or so, but is still a failing point.

Thanks for the info, I was not aware of this, I'll be maxing out around 400 hp IF I get that high, so It would seem like I don't have much to worry about.

jeffball610 wrote:Yes the 7-bolt is known for crank-walk and people even developed the term for it. However, why have the EVO 8-9 motors not shown this failure. I'm not too educated on the EVO motor, but know that is an extension of the 7-bolt design. An evolution of it. I like to think that crank walk occurs because of poor quality control and the oddness of the crank bearings. (along with everything else I listed above) You need to find out what size each bearing is for each spot. They are not all the same size as in most motors out there..

Could it be that Mitsu. recognized the problem and repaired it? I would think they would have. Now what changes were made to the bottom end of the EVO 8-9 motors, I don't know.

jeffball610 wrote:I for one have a 7-bolt 2G bottom end (8.5:1 pistons) and a 1G head. Yeah the 2G headis a better design, but the 1G flows more stock and is cheaper for me to get. Everyone has their reasons, and those are mine. Anyone reading these posts can make their own decisions.

Cool, seems that we are gonna have 2 completely opposite engines. Is yours a 2.4? We also seem to aggree on each person doing what they want.

jeffball610 wrote:I'm not one to tell you what you should do,

jeffball610 wrote:if you're looking for 2.4L engines, stick with the 7-bolt types.

That sounded like telling someone what to do to me.