Gotta love the interference motor.

36284 Views 40 Replies 15 Participants Last post by Maddler, Jan 6, 2010

BakerGs

Discussion Starter · Jun 8, 2008

I currently own a 2000 Gs with 83k on it. So last saturday night me and my girlfriend decided to take a trip over to the inner harbor. I was cruising down 295 and all of a sudden my car shuts off. I pulled over and popped the hood while im using my cellphone for light lol. I could smell burning rubber and i had a feeling my timing belt snapped. Alot of fun sitting on the side of 295 for an hour and half waiting for AAA lol. So i got it to the shop and just started taking shit apart today. The belt looked like shredded wheat, it ripped the end of the crank sensor off and bent the plate behind the crank gear. After cleaning all the shreds off the crank gear i took the valve cover off to check the valve train. There was no play with the rockers so i was a little happy that i might have a chance of no bent valves. I took the rockers and guides off and took the spark plugs out. I went through 3 cylinders with no leaks through intake and exhaust. I had the biggest smile on my face at the moment knowing that my valves might be ok. The 4th cylinder came and all u hear is 200 psi blowing through an intake valve. That smile was quickly removed. So now i gotta rip the head off and make sure nothing is cracked and just look at the condition of the valves. Not sure if i wanna send the head to a machine shop or just drop valves in it. I know its best to send it out but im a little tight on money right now.
At the moment i hate mitsubishi for making this motor interference.
RAWr!

1 - 20 of 41 Posts

PharmEcis

· #2 · Jun 9, 2008

fasteclipse3 said:
the 4g64 is a non-interference motor http://en.wikipedia.org/wiki/Mitsubishi_Sirius_engine#4G64

Do you believe everything that is in Wiki's?

An interference motor is any motor where the valves and pistons share the same space at different times. The 4G64 definitely does that. There is no recessed dome on the 4G64 pistons, let alone valve relief's.

To the OP... The head needs to be resurfaced and you should at least do a valve job on the valves you have to replace or the new valves won't seal properly.

reallyniceguy

· #3 · Jun 9, 2008

stupid manufactureres.. i wish all of them were non interference like my ze engine.

Im about to dish out some money to get timing belt on my eclipse changed

BakerGs

Discussion Starter · #4 · Jun 9, 2008

Yea Pharm now that i think about it i should get the head resurfaced. Best stay on the safe side.
I'm gonna get the head off sometime this week, hopefully i can make some time.
Thanx for the advice Pharm

NYSELatino

· #5 · Jun 9, 2008

Man, that really sux!! And it only went out at 80K!!! I just recently changed mine out at at 123K, I was getting a little worried about it and heat is starting up here in Phoenix so I figured I better get it done. Hopefully you get that all taken care of with not too much pocket damage.

BakerGs

Discussion Starter · #6 · Jun 9, 2008

Yea man it does kinda suck but luckly i work at a shop. :]
all together in parts its around $600. not too shabby.
it sucks cause i just started buying parts for doing a turbo setup and this shit happens.
btw im currently driving a Plymouth Acclaim lol
chick magnet for sure

cfeyhris

· #7 · Jun 10, 2008

might as well build the motor now so it can hold the boost. id hate to have to see you post another thread saying that you blew your motor while running boost.

oh and by the way the acclaim is pimpinn

Barcode_Racin

· #8 · Jun 10, 2008

Lol my original timming belt lasted longer then the Connecting rods :fever:. Sorry for the bad luck.. but be ready for the worst, my engine died at 129k... Now I'm driving at 3212.3 miles on a brand new block head internals.

Just had to gloat sorry

BakerGs

Discussion Starter · #9 · Jun 10, 2008

ohhhh gawd i dont need anything else to go wrong with this car lol
i dropped a rebuilt 5 speed in it when i first got it cause the person who had it before me i guess grinding the gears like nuts. the bearings were in bits and the shaft had so much play in it that my clutch rubbed against the bell housing lol. love sitting at a stop light with the smell of gear oil and ur tranny dead lol
more money goes into fixing this car then doing anything to it lol
2000 bux for the tranny and it was hard as hell to find one.

bad mojo

· #10 · Jun 15, 2008 (Edited)

fasteclipse3 said:
If that was the case he would have 8-16 valves that need replaced like the dsms do when their belt goes and not the 2 valves that actually were bent.

not true. with an interference engine, you can almost guarantee contact between the pistons and valves when the timing chain is out of the equation.

how much contact is another story. since the valvetrain and bottom end are no longer in sync, contact is hit and miss. there's no certainty that all, half or with a slim chance in hell, any contact is made.

Have you ever checked the piston to valve clearance in a 4g64?

why?

checking piston to valve clearance requires the head, bottom end, and timing components to be assembled.

they're never going to touch with the timing belt on.

the only way to know for sure is to turn the assembly with the timing belt off and feel for resistance.

BakerGs

Discussion Starter · #11 · Jun 16, 2008

actually all the valves hit.
u can see the marks on the pistons from where they hit.
all 16 valves are getting replaced.

steadly2004

· #12 · Jun 17, 2008

fasteclipse3 said:
Take the timing belt off the plugs out and spin the motor by hand you will see that it will go all the way around without hitting. On a 2.0 4g63 it will hit and not make a complete revolution. Call it whatever you want.

I don't believe it. If that were true, this dude wouldn't have marks on his pistons where the valves hit?

And I'm pretty sure that all that stuff will come in contact without the timing belt. My machinist specifically said don't rotate anything until I get the timing belt on, I know thats a good general precaution, but I'm pretty sure its because they DO hit. Or maby because I had both the head and block planed, I have less clearance than stock? And an higher lift than stock...

PharmEcis

· #13 · Jun 17, 2008

fasteclipse3 said:
Take the timing belt off the plugs out and spin the motor by hand you will see that it will go all the way around without hitting. On a 2.0 4g63 it will hit and not make a complete revolution. Call it whatever you want.

fasteclipse3 said:
Whatever you say. I guess you've done a timing belt yourself like never eh? I have 272 cams and mine do not hit There is a small amount of clearance. The clearance we are dealing with are in the thousandths not like its alot. If the 4g64 was interference it would have valve reliefs like the 4g63 does.

You continue to prove your complete ignorance of the subject matter. Do you even know why the DOHC head found on the 4G63 or 64 or 72 will not allow the bottom end to be spun in a complete circle? Do you know why you can do it on either the SOHC 64 or 72?

Just in case you missed it the first time I said it, AN INTERFERENCE ENGINE IS DEFINED AS AN ENGINE WHOSE VALVES AND PISTONS SHARE THE SAME SPACE AT DIFFERING TIMES. If an engine is properly timed, there will never be interference. When the cams in a head are at the proper degree, the SOHC heads from Mitsu will have all valves closed or mostly closed allowing the bottom end to be spun freely without contacting anything. Change the degree of the cam and all of a sudden a set of intake or exhaust valves for a particular cylinder will open more and now you WILL make contact. Why does the DOHC heads not allow this? Since there are TWO camshafts with different centerlines, lobe configurations etc, THERE IS ALWAYS A SET OF TWO VALVES OPEN WHICH WILL ALWAYS CONTACT THE PISTONS IF YOU TRY TO ROTATE THE BOTTOM END.

If an engine skips time and then has piston to valve contact, IT'S AN INTERFERENCE ENGINE, PERIOD.

You may not pass go, you may not collect $200, but you may burn in hell.

Do you even realize why there are valve reliefs in a piston? Valves do something called floating. That's why they are there.

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steadly2004

· #14 · Jun 17, 2008

fasteclipse3 said:
Whatever you say. I guess you've done a timing belt yourself like never eh? I have 272 cams and mine do not hit There is a small amount of clearance. The clearance we are dealing with are in the thousandths not like its alot. If the 4g64 was interference it would have valve reliefs like the 4g63 does.

I installed the timing belt on my new motor, but thats about it.

Then tell me why that dude has valve marks on his pistons?

steadly2004

· #15 · Jun 17, 2008

BakerGs said:
actually all the valves hit.
u can see the marks on the pistons from where they hit.
all 16 valves are getting replaced.

fasteclipse3 said:
If the cams are installed in the car that means some valves are going to be depressed you will never have all valves closed at the same time so explain how it is if the valve is in a fixed open position and you rotate the bottom end and it doesn't hit that it is still "sharing the same space" the answer is it doesn't. So take your little flame contest somewhere else.

:dunno:

FlashBlueRS

· #16 · Jun 17, 2008

LOL, just checked the Wiki link. If it's on Wikipedia, it must be true.

Wikipedia said:
The longitudinal 4G64 is the second largest variant, at (2350 cc). Early models were 8-valve SOHC, but a later 16-valve SOHC and DOHC version was also produced. All used MPFI with an 86.5 mm bore and 100 mm stroke. The 4G64 was also available with gasoline direct injection. The version used in the Chrysler Sebring/Stratus coupes produced 152 hp (110 kW) at 5500 rpm with 162 ft·lbf (214 N·m) of torque at 4000 rpm. The Chrysler version features fracture-split forged powder metal connecting rods. The 4g64 is an interference motor like the 4g63 and fasteclipse3 is a dumbass.

XwP1ayawX

· #17 · Jun 17, 2008

People aren't taking into consideration valve stretch. Sure if you spin the cam by hand you may have a bit of clearance with a piston at TDC, but under load and different rpm's valves tend to stretch when they are open. A busted timing belt while a certain number of valves are wide open is a recipe for disaster. I bent 8 when my belt went

steadly2004

· #18 · Jun 18, 2008

http://www.car-stuff.com/carparts/mitsubishieclipse20002005daycody952321.html

Application Info
Make: Mitsubishi
Model: Eclipse
Year: 2
Brand: Dayco
Part: Timing Belt
SKU: DY95232

2000-2001: 4Cyl 2.4L GAS, FI, VIN "G", 4G64, Interference Engine RS
2000-2005: 4Cyl 2.4L GAS, FI, VIN "G", 4G64, Interference Engine GS
2001-2005: 4Cyl 2.4L GAS, FI, VIN "G", 4G64, Interference Engine Spyder GS
2002-2004: 4Cyl 2.4L GAS, FI, VIN "Y", 4G64, Interference Engine GS
2002-2004: 4Cyl 2.4L GAS, FI, VIN "Y", 4G64, Interference Engine RS

I couldn't find much official data on the subject.

bad mojo

· #19 · Jun 18, 2008

fasteclipse3 said:
If that was the case he would have 8-16 valves that need replaced like the dsms do when their belt goes and not the 2 valves that actually were bent. Have you ever checked the piston to valve clearance in a 4g64?

BakerGs said:
actually all the valves hit.
u can see the marks on the pistons from where they hit.
all 16 valves are getting replaced.

just in case it was missed.

PharmEcis

· #20 · Jun 18, 2008

Arguing with DNS is like talking to rock. My dog is smarter than you, for sure. Considering that I have professional experience assembling race engines, you would think I would know what I'm talking about right? Nah, listen to the guys who got their information on the Interweb because they are GENIUSES and can regurgitate erroneous information.

Not trying to be a prick but if I come off as one so be it. DNS is wrong. At this point I'm building over two engines a week along with dropping them in cars at DTM. Full assembly at that, not just slapping together components. I must be doing something right if my engines are making over 600awhp on pump gas. The motor that was in our National Championship winning car last year was built by me too, so do you really think that I don't know what the fuck I'm doing?

Stop being a keyboard warrior who only has experience working on his own personal car. I've built over 150 EVOs at this point and numerous 1-3G Eclipses in just a few short years. I think I have a right to come off as an ass once in a while when some douche bag wants to talk about something he is obviously wrong on.

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