Banging valve...and now...

Looking for some diagnostic help here.

When I run my truck at interstate speeds for more than a few miles, or load the engine for a mile or 2 (like a long hill), I get some serious valve pounding. Not sure if a valve is sticking, a lash adjuster is sticking/not oiling, or perhaps sucking a valve a bit (not enough to hit the piston, if so)? Along with the obvious hammering by the rocker, the exhaust gets very loud and mean sounding (like the sound, but not good), and I feel a not insubstantial loss of power. Also noticed that the next day I will get a SHITLOAD of carbon out the tailpipe at startup. Leaves a big black skid mark on the ground. This is an intermittent problem, if I shut down and let the engine cool, it usually goes away. I can also just slow down and drive ~40mph on surface streets for a while and it will go away.

I've also noticed that if I let the truck idle all the way up to operating temperature, this is less likely to occur. Not that it won't, just less often.


And now...

Noticed when I fired up my truck this morning, my high idle is gone. I mean, just gone. Engine fires up fine, but idles REALLY slow (~250-300rpm). Checked my choke lead, it's still connected and getting power. This one is a bit odd. Truck still ran fine, but wanted to die at stop lights until it warmed up.

I post both of the issues in one thread because I get the sneaking suspicion they may be related. Not sure, though.

Thanks for the help!

I would first go by the screwed up machine shop you have and show them the problem, see what they will do.

have you checked your Air Filter?

The air filter is a brand new K&N, so that isn't an issue, I don't think.

As far as taking it back to the machine shop...it just started a couple weeks ago, ya think the machine shop F'd up seating a valve? Certainly possible, and I CAN give em a call on the morrow.

it took then 8 months to do a valve job,,,,, so ya think they screwed the pooch. I have a feeling they did. But I'm not there to see or look at it. It's possible it was the wrong head gasket and blocked the oil port to the head. First gens don't have an oil galley to the head. Splash and spray is all it gets. Yours has one for the hydraulic adjusters.

Well, I do know the ports are clear. Made double-damn sure if it when the head went on. Soo, gotta have a chat with Rick's...



Edit:

This head went on the truck last spring, been 3/4 of a year.

mine did the all most exact thing, no idle at all and running just plain bad. The cause was the vacumn line from the pvc to the base of the carb, had a split in it. Only did it radonmly. Only found it by accident, I was revving it up to get it to stay running and a saw the hose actually open at the split.

Quote:

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Originally Posted by LiL Bastard

mine did the all most exact thing, no idle at all and running just plain bad. The cause was the vacumn line from the pvc to the base of the carb, had a split in it. Only did it radonmly. Only found it by accident, I was revving it up to get it to stay running and a saw the hose actually open at the split.

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That is another reason for your problem listed in the Haynes Manual

Well, a bit of an update. I took my own sweet time trying to get ahold of the the shop owner. I did so today. He seems to think it's a bad hydro-adjuster pumping itself up and locking the valve open. This seems plausible...

His explanation for not thinking it's a valve/seat/guide is that in his experience, a valve that sticks stays that way. The head is out of warranty now, so I can't see him having much desire to lie to me about it. In fact I'd think he'd want me to bring it in and spend money.

As for the high idle issue, I found it and fixed it...but I'll be damned if I remember what it was! (was something small and stupid)

sounds like a good diagnosis. I bet the port is plugged with some crap. Take it apart and clean with diesel fuel.

Gonna wait til taxes get back (soon) and just get Starion OS valves installed, cam done, hydro-rollers in. Been talking about it too long, action time is gotta happen.

Go Stiff Arm :-) I have all the P/N's

http://mmeierle.com/images/Max/Blue%...2005%20008.jpg

Hmm..they make a stiff arm roller?


= )

It's over head cam. I would go solid cam followers like LSR has pictured. It's unless you are going to use some wild cam that needs the ramp angle. It makes for 1 less thing to go wrong.

Well, I concede, you both are right. Would be cheaper as well. It IS getting a longer duration cam, but I don't think the grind is particularly radical.

My cam has a 284 duration, I needed the Solid Lifters because my springs are so stiff the Hydraulic adjusters were crushed...

as a side note they're sourced from a 1.8 motor, the 2.4 never had solid lifters. Also you would need a completely different cam to run a Roller setup.

You also need a different cam to run mechanical rockers as the profiles on the lobes would be different...

Quote:

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Originally Posted by pennyman1

You also need a different cam to run mechanical rockers as the profiles on the lobes would be different...

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Not True, How they're adjusted have nothing to do with the rocker interface to the cam, or the cam profile.

i have pulled adj. rocker arms out of 2.0Ls be for.
and installed them in both a 2.6L and my 2.4L

Years back when john baker sold cams for these 2.6 motors, the cut off for adjustable rockers was 84 - 85 on was a different cam for the hydralic lash adjustors with a different profile. The ratio on the arms are the same, but there must be some difference to require 2 different cams.

Watching the debate, will go with mech. rockers, need a new cam either way I slice it.

Intake A MD023225 qty 2
Intake B MD040780 qty 2
Exhaust C MD023226 qty 2
Exhaust D MD040781 qty 2

Adjuster screw MD065628 qty 8
Locking Nut MD000961 qty 8

cost me $184.27 from the dealer back on May 5, 2005

Thank you, sir. Will check the dealer on Monday, they won't likely have them, so my next call will be to an import auto place nearby that has a knack for finding things.

Dealer will order them from the Atlanta parts Warehouse.

LSR....I notice the intake side of those rockers have the lobe for the jet valve. Any reason to not just cut them off? Can the exhaust side be used for the intake? I've noticed a lot of times the rockers for these things are common save for that jet valve lobe. Can't imagine having the lobe gonna hurt anything, but less metal is less metal.

Was able to locate the PN with no issues, had to wait on funds. Getting ready to order in the next couple days.

Laziness...Saw them off and grind them smooth. No swapping intakes and exhausts, they are specific positions of A, B,C & D; 2 of each. These are actually 1.8L motor P/N's there is a lot of commonality of Mitsubishi parts in a series. the 1.8 is another SOHC 8 valve Motor, in the same family.

Perfect, thank you for the quick reply.

Yep just as LSR said. Whack it, grind it, drive it... Oh and take pictures of the process and turn it into a porno mag for the rest of us to enjoy. :))

AAANNNDD, I went to order them and guess what? Only one of the A Intake rockers exists in this country (in Mitsu warehouses/computer system), and none of the others are available....any ideas?

Not real excited about the junk yard route, if I replace em, I want new.

Found exhaust rockers on Fleabay, assuming they will work?

http://www.ebay.com/itm/New-Ram-D50-...#ht_1535wt_905


G32B intakes work?

http://www.ebay.com/itm/New-85-86-87...ht_1433wt_1163

Hey Acuta 73. Did this ever get finished?