4G63T spun bearing?

Question

Well,I need to ASK a question this time...The 1990 6-bolt 4G63T in my Summit GTX has done about 200,000 km, and under acceleration blows quite a bit of oil smoke, meaning the rings are shot. Needs valve stem seals too. Oil was pretty low, just on the bottom of the dip stick, meaning there was about 1L left ie not run dry. I've had it that low before.Last night it was running fine, but this morning the engine rattled when I tried to start.Pulled off the rocker cover, and found one inlet lifter (the noisy one) was not pumped up at all and the rocker was floating about under the cam. Put in a good spare lifter, and the rocker was again tight on the cam.Topped up the oil, tried to start, and got lots of valve clatter, the engine ran like the timing was way off. There was no audible big end knock.  Valve clatter suggests no or little oil pressure is getting to the lifters. The standard (Eclipse) oil pressure gauge shows normal.Disabling the fuel and the starter spins the engine OK, no valve rattling or knocking noises.The cam timing SEEMS to be about right in that the pulley TDC mark and the cam sprocket marks seem to line up on the right places. This suggests that the hydraulic tensioner has not caused a cam timing problem.With the plugs out, I can turn the main pulley with an 8" ratchet arm, till it gets to a point that I just can't move it. Surely the valves springs are not that tough?  The starter spins the engine over smoothly, no audible "hard" spots that would suggest a really jammed big end.I know I have to take the sump off and have a look ($sob), and I was planning full rebuild anyway.What's the consensus? Spun bearing?Stewart DIBBS

simpleton · Accepted Answer

"Topped up the oil, tried to start, and got lots of valve clatter, the engine ran like the timing was way off. There was no audible big end knock. Valve clatter suggests no or little oil pressure is getting to the lifters."

Your spare lifter has air in it. it will clatter and tick until it get pumped up.

If you would like, I can point you to vendors who sell the 3rd generation lifter cheap.

So , Stewart is it a set of Wiesco's on Eagle rods or Ross on Pauter's?

You should talk to Marco over at Magnus in Woodbridge.

Look into the light Stewart, DSMLink and an EVOIII 16G turbo are calling.

res0jhe2 · Answer

Not much technical to offer since the motor  will need to be opened up. I do agree with simpleton though, EVO motor. I think I would just rebuild your current with the good stuff. Actually stock that project car of yours should scoot...Take care, L

Stewart DIBBS · Answer

Its actually a bit slower off the mark with the turbo than with a n/a 4G63 DOHC (first engine I used), though this is in part because its still got the n/a exhaust system on it, which is 2 1/8" vs 2 1/4" stock turbo. I'll be replacing it with a 2 1/2" all the way through at the same time I put in the rear diff and get the AWD working. Its fine up to 5000rpm, then the small pipes cause to much back pressure.

Once it gets in to 2nd, the turbo torque kicks in, and keeps pulling in 3rd,

4th and 5th. I've had it up to about 180kmh then ran out of road.

Stewart DIBBS

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simpleton · Answer

"Its actually a bit slower off the mark with the turbo than with a n/a 4G63 DOHC (first engine I used), though this is in part because its still got the n/a exhaust system on it, which is 2 1/8" vs 2 1/4" stock turbo. I'll be replacing it with a 2 1/2" all the way ."

Both OEM systems while durable and quiet, are horribly restrictive. On the old 1G car I went from stock to a David Buschur 3" turbo-back system and instantly that turbo would make boost like there was no tomorrow. Stewart,

2.5" is a pretty decent compromise between civility and performance. Bigger is better but more rude, I run nothing but 3" and the drag guys are moving to 3.5" What Exhaust components are you using? Manifold, O2 housing etc...

Nobody U. Know · Answer

First thing I'd do is check that valve. Watch it with the cover off and see for sure if is moving. I've lost a rocker and it felt like bad timing, albeit at a high RPM range. If you put a good/new lifter in there, it will take a few minutes to pump up. It sounds really bad when you do that.

I doubt you spun a bearing with good oil pressure, so you may be seeing the valve causing your problems. If you do have a ring problem, pull the plugs and clean them. I've seen a bad idle with just bad valve seals (oil on plugs). It takes a bit to burn off that oil. I've had stem seals so bad at one time, that if you stalled the engine cold, the thing wouldn't start until you cleaned the plugs.

Stewart DIBBS · Answer

All standard parts. I could I suppose mill out the exhaust manifold and O2 housing, and put a 3" SS down pipe to a 3" cat, then 2.5" for the rest. It not and will never be a drag car. (I'm 54 and past that). Mostly I just see off the local Honda Civic wanna-be's with fart pipes (except for the guy with the 98 Civic with turbo and NOX ...)

Anyone have some parts lying around?

Stewart DIBBS

simpleton · Answer

"Anyone have some parts lying around?"I sold off that stuff a few years back but allow me to advise you to look at 2G DSM exhaust manifolds and oxygen sensor  ,  ,  ,  is better yet but a hard find at the junkyard. On the topic of cheap OEM Mojo,2G turbo pistons on your existing rods (w/ the small end reworked) raise your static compression to 8.5:1  fun while you're in there.

Stewart DIBBS · Answer

Spent half today realigning the cam belt after my mistake trying to turn the cam : it was 1 or 2 teeth off on the crank gear. Quite a bit less room to work in the Summit than in an Eclipse, but its spot on now, including the oil pump.

I have compression, oil presssure under the lifters, spark on all 4 (via spark gun), fuel on the rail, power on the injector resistors. It should start, but it won't even fire. I've no reason to believe that the ECU is not firing the injectors. I've tried some oil in the cylinders, and got a "sneeze" from the engine.

It too damm hot outside now, so I've cleaned up and repaired to the fridge for an ale. Any suggestions to get this #@$*! started? More oil in the cylinders to seal the rings?

Stewart DIBBS

Stewart DIBBS · Answer

Did a compression test ... zero on all four. Verified the cam belt alignment, spot on. Had a close look at the intake valves, and all EIGHT are depressed about 3mm, with the rockers floating around. Checked my spare head ... not the same, valves are up and the rockers tight against the cam.

So I guess that when I started it the other day the cam belt jumped a tool or two, and bent all the valves. All makes sense now. Lets hope the exhausts are OK, but after 200,000 km, might need some (or all) new.

Oh well, I have no choice but do a full rebuild.

Stewart DIBBS

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Gyzmologist · Answer

A compression test will reveal a spun rod bearing.

4G63T spun bearing?

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