'90 MM 2.4L FI Build

[royster]

Wow, that's quite a photo collection!

It's interesting how the exhaust valves are not consistantly dirty, but some more than others (EGR). On mine, I also noted that #4 (closest to the firewall) had a lot of gunk, because that is where the oil drains most...and that seal was not even working (the valve guide had dropped 1/2"!). You might want to check the valve guides for any slippage: I understand that was one of the problems they had with these engines. It's a very simple fix, if you can find the right guy who knows his stuff.
[EDIT] Seeing's as your seals are still on there, likely the guides are okay. The valve seals actually seat on the valve guide. It's amazing how much I forgot in the few weeks since my repair.

I used a Dremmel tool with a wire wheel to clean the carbon off the valves. Very few of them would spin freely in the closed position...particularly those whose valve guides had slipped down. I coated the valves with installation oil before putting them back in.

Those seals are a struggle to get off, however so you can, just being careful not to scratch the stem surface: scratches will allow oil to leak down.

My memory is returning to some degree: you put the valve in first, then the straw thing goes on the stem of the valve, then the seal, then replace the springs.

You do the Hokey Pokey and you turn the head around...wait, that's not right...

I was also very anal-retentive about the head bolts: cleaned them off real good, and cleaned oil/Jimmy Hoffa out of the bolt holes. I didn't want any gunkus~funkus affecting the torque reading.

[mitchi]

Yea, I'm still working on that picture deal, seems once their there, I can't pull them back out. But, what the hey, the more pics the merrier.......sometimes.

All of the valves turned freely in their slots. I've been to 4 different stores trying to find lapping compound with no luck. But, no worries, as I intend to take the head and have it magnafluxed, and checked for flatness. Hopefully they'll clean it too.

I still have to source the seals yet too. I have a bench/drill in vise with a wire brush on it. However, I think I read or watched a utube video about using a brass brush. So off to HF again tonight. Maybe they'll have the compound.

Thanks again royster.

[royster]

If you ordered a good head gasket set, seals (and the cocaine straw) will come with it. My second set of seals I ordered through NAPA...but they didn't have the straw. Depending on the head gasket set, you might end up with two different types of seals, one for exhaust, one for intake. I don't recommend the intake (rubber) seals: get another set and do them all the same (plastic/metal). The set might also confuse you with itty-bitty valve seals: the same head gasket set is for the 2.0, and thus has jet valve seals and a tiny cocaine straw, along with some o-rings.

If you go to the NAPA online or RockAuto site, there will be pictures of what you get in the set you order.

Very likely the shop will clean the head. Follow through with the recommendation of Jefferson Airplane in the song, "White Rabbit" : "Feed The Head".

[mitchi]

Well, got the seals removed.....not Purdy. They were a booger to get off, hope I didn't nick any of the seats.

Next is to take the head to a machine shop, and get it checked.

Do or are these bolts reusable?

P1040513.jpg

[royster]

are these bolts reusable?

Absolutely, and you're supposed to keep them in the order they were removed...so as to put them back in the same hole they came from. It's a marriage issue, I guess.

Not only should you re-use them, but good luck finding replacements for them!

The used valve seals, as illustrated, makegood miniture wind chimes you can hang from your rear view mirror.

[mitchi]

Yeah, I figured as much, thats why they are positioned the way they are.

In an arrow pattern, pointing to the front of the engine.

I know I probly should have stuck them in cardboard, but, thankfully, or not, no one will screw with them as they are. No young kids, dogs, runningt around here, so purdy much everything stays as is, till I get out there and screw things up.

So far, haven't upset these. Just dropped a container of gas with carb parts soaking. Had to air out the garage all night long.....sucked.

[mitchi]

Got all the valves and seals out.

What is a good soaking agent to use on these things?

Can I scrap on these thing w/o damaging the valves? Looks like lots of buildup on them. Right now, they are soaking in some seafaom, with very little noticeable cleaning.

And will a wire brush be ok to use?

Thanks for your responses.

[royster]

Wire brush will be fine, just stay off the stems. I used a Dremmel tool with a small wire wheel on mine. With a Seafoam pre-soak, they should clean up just fine.

[mitchi]

Thanks royster, I kinda figured these were like MC fork tubes, staying away from the part that slides in the guides/tube seals.

So as to not nick the part that needs to seal the fluids. That I understand.

So soak and brush, scrap a little, then soak some more.


P1040518.jpgP1040519.jpg


Soaking next to the bench/vise mounted drill/buffer/wire brush.

P1040521.jpg

[Rahtid]

Did you order the head gasket set,

[mitchi]

Did you order the head gasket set,

No I have not, recommendations?

Machine shop called and said , "my head is cracked"............I need another.......crap.

[BradMph]

Sorry to hear about your bad news.
Have you checked to see if head can be welded. It really isn't that difficult for a good shop to do. In most cases it also increases the strength of the head in areas that seem to find the stress. I have been using a welded head for years and it shows no sign of reoccurring.

[mitchi]

So, I asked them if it could be repaired and they said no....so apparently they are not as good as a machine shop as peeps locally talked them up to be.......or they are right and the crack is that bad.

They told me flat out....I need a new head.

So, looks like I'm in the market for another head. Hate to go to the local pull-its, and get another that is cracked.......cause it's costing me damn near 100 bux to have these darn things checked for cracks.

And they expensive as heck from places like Autozone, O'riely's and such.

[geezer101]

So, looks like I'm in the market for another head. Hate to go to the local pull-its, and get another that is cracked.......cause it's costing me damn near 100 bux to have these darn things checked for cracks.

...I feel your pain. I'm chasing a non hydraulic flat tappet head - there's an over abundance of hydraulic heads and it's russian roulette every time you march into one of these places with your tool box under your arm.

[BradMph]

I would sure like to see the crack if you get a chance to take images anytime. Makes me wonder when machine shops give you news you never expected, especially if they had my part for more then a day or so. These Mitsubishi heads are tender in many cases and the clearances between valves and stuff can be minimal. A little off on timing and temperature climbs some time causing a little more stress then usual, pull it into garage where it cools too quickly and the hairline begins. Your not the Lone Ranger when it comes to cracked heads on these things.
My first one cracked after I moved to a freezing climate and left the water in radiator all winter because of a broken trany. Cracked head, intake manifold bottom almost fell out, radiator split, 3 freeze plugs popped. Second head cracked the entire length of cam shaft. 3rd head crack on an over heat that I caught early and pulled right over. Found a quarter size hole under cam shaft area. 4th head..flat tappet has been good so far. Oversized radiator with electric fan and a 180 degree thermostat so cool water starts a little earlier into engine. Keep us informed, Heads are available still.

[mitchi]

I would sure like to see the crack if you get a chance to take images anytime. Makes me wonder when machine shops give you news you never expected, especially if they had my part for more then a day or so. These Mitsubishi heads are tender in many cases and the clearances between valves and stuff can be minimal. A little off on timing and temperature climbs some time causing a little more stress then usual, pull it into garage where it cools too quickly and the hairline begins. Your not the Lone Ranger when it comes to cracked heads on these things.
My first one cracked after I moved to a freezing climate and left the water in radiator all winter because of a broken trany. Cracked head, intake manifold bottom almost fell out, radiator split, 3 freeze plugs popped. Second head cracked the entire length of cam shaft. 3rd head crack on an over heat that I caught early and pulled right over. Found a quarter size hole under cam shaft area. 4th head..flat tappet has been good so far. Oversized radiator with electric fan and a 180 degree thermostat so cool water starts a little earlier into engine. Keep us informed, Heads are available still.

WOW....I sure wiil......

[mitchi]

I would sure like to see the crack if you get a chance to take images anytime. Makes me wonder when machine shops give you news you never expected, especially if they had my part for more then a day or so. These Mitsubishi heads are tender in many cases and the clearances between valves and stuff can be minimal. A little off on timing and temperature climbs some time causing a little more stress then usual, pull it into garage where it cools too quickly and the hairline begins. Your not the Lone Ranger when it comes to cracked heads on these things.
My first one cracked after I moved to a freezing climate and left the water in radiator all winter because of a broken trany. Cracked head, intake manifold bottom almost fell out, radiator split, 3 freeze plugs popped. Second head cracked the entire length of cam shaft. 3rd head crack on an over heat that I caught early and pulled right over. Found a quarter size hole under cam shaft area. 4th head..flat tappet has been good so far. Oversized radiator with electric fan and a 180 degree thermostat so cool water starts a little earlier into engine. Keep us informed, Heads are available still.

:

Hey Brad, here are the pics:::::

[mitchi]

Well, some good news.....................I took the machine shop the head off this locked-up engine, and its not cracked, but has bent valves and needs a valve job.

So, guess I'm looking at valve guides new valves and naturally seals.

Does that sound about right?

[BradMph]

Hey that is fixable! absolutely 100% fixable. And if you get it fixed at the right place it shouldn't ever crack there again. I have seen many heads exactly like yours, this is the nature of the older cast heads for some reason. But do not throw that away. A good shop will grind a little in and fill it like a filling on a tooth. It will bond those egdes back into one if the welder knows his technique. After welding you probably do not want to grind it to smooth it out. Leave it as the welder has. Unless he piled a 1/2in of molten metal on it. If you grind on it, you will probably crack it again.
When I got my head from a place that repairs them, I was chatting with them and just mentioned that I was going to clean it up and do a little work to smooth the weld out. He friggin responded instantly, saying no no no, leave it alone or it will not keep it's strength. So far he has been correct and I have had the temps in a hot range a few times after installation.

Thanks for those images. It's always the same place I see these cracks, or the MCA jet housing.

You can almost do your own valve grind also. Unless the valves are tweaked bad. Just replace the guides and seals, install new valve and get the wooden dowel tool with two rubber ends and some compound and go to it. Might as well replace the valve springs also since your there. I think $45 was what I paid for high performance Schneider springs.
Or let the machine shop do it all and if it F*ks up, drive it into his shop's front window. lol

He only has to replace the valves that are bent. If they are really bent and not just wobbling. Save them also so we can see if there are severe wobble marks on the stems. Bent valves usually happen on a timing belt snap and they hit the pistons. If that hasn't happen, most the time they are just carbon wobble marks on the stem. You always want to replace the seals also. Its a super easy job to do. guides are a little tougher but backyard mechanic can do it. Tools are simple and I have listed them in my thread when I reseated my valves and replace seals and springs for the first time.

Valves that are bent usually wobble around in the guides. The stems will kind of look like this image sort of.
wobblevalve.jpg

[mitchi]

Hey brad, I told the shop, I would do the valve job, cause I figure they trying maybe-maybe not, to make some money off of me.

I figured there's peeps like you that will help me with this. And I applaud you for doing it. What I learn here, I will certainly pay it forward, that's for sure.

I will certainly post some pics of the other head, once I get it back. They asked me if I wanted them to go ahead and shave it, I may have been over excited, knowing I had an uncracked head, and told them to do it. Maybe it needed it, maybe not......I have no ideal.

I think I'm going to be into having these heads checked......200 bux.

Then when I get it back from being checked for cracks and shaved, I have to pull the valves and that will be another 150 to 200 bux to get this head put back on the motor.

We'll see. Once again, Thanks Brad.

[mitchi]

Dayyyyum.....how long should it take to shave a head..................?????????????

Question: Whats the difference between the 12pt 12mm bolts and the (forget the size) allen head bolts?

Which ones are better than the other?

And can I use bolts from another engine into mine?

[geezer101]

$200 to get a head inspected? Really? They give it a hot tank, check to see if the head is still 'true' and do a pressure test. This is barely an hours work... I spent an extra $90 on top of that and got all my valves and seats cut and a reface. I think these guys are messing with you. If there are other car affiliated groups in your area, put the word out to them that you're after a good machine shop. Someone who's been building cars for a while will know a small shop somewhere that does top notch work without charging big cash.

[mitchi]

^^^^yea, I got feelers out.......not coming up with much. ^^^^^^

All I can do is wait and see.

[mitchi]

OK.......been procrastinating long enough. Got my settlement from my motorcycle accident, now have a little cash to do something about getting this truck off these ramps and out the garage. Wife is pissed this things been in here for well over a year now.

Need a little advise on what to do.

1. Buy a new/re-manufactured head from a parts store, and just install and go. ($490 + core charge)

2. Have this other head that's been checked for cracks and shaved rebuilt by a machine shop ($180 + parts and labor) which may come out to same amount of money.

Plus after removing the cam from the above head, noticed scarring/grooves on one of the cam journals and on the cam itself. So, I'm assuming I wasted 120 bux to have this head checked. And that the first option is gonna be my best direction.

After all that is said and done, whats the consensus?

Next question is, if I do buy option number one, will I have to do anything with the engine. Does anyone think having a new head will endanger the engine in any way.

I think I posted some pictures of the engine cylinders already. There are visible crosshashed marks on the walls, and no visible nicks or gouges.

Appreciate all the responses.

Anyone.....anyone................??????????

[crvtec90]

490 sounds high for a rebuilt head but if youre cam and journals have scoring then its gonna get worse before it gets better. Does the rebuilt head come complete with valves and cam? Alabama cylinder head sells a non jet valve casting that's supposed to be decent but I think it comes as a bare head.