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what does a 3.1 run like...(EDIT: RESULTS ARE IN...)


Guest TurboSedan
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Guest TurboSedan

i just replaced the timing chain and started it up. it started, but ran really rough and lopey...i don't know if it was just cold and/or doing an idle relearn or what. it's really freakin loud right now because of the open downpipe so i can't really hear the engine much

 

i installed the timing chain exactly like the directions described...cam dowel pin @ 9 o'clock, with the cam sprocket timing mark straight up 12 o'clock, and the same with the crank sprocket...timing mark pointing straight up. please don't tell me i have to tear the front of the motor apart again :(

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Well....one tooth off...valves and shit are going to be opening slightly later or sooner. Allowing for not enough air to get into the combustion chamber.....I'd say it would run like shit.

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All the timing chains I have seen also line up with the cam gear mark down @ 6 o'clock position and the crank gear mark up @ 12 o'clock position

 

It sounds like you have it in properly and lined up goodenstraight per your instructions, at the same time it sounds like its running 1 tooth off, any possibility of a vacuum leak ?

I cant even imagine it running 180 degrees out of phase so I think your instructions are good :roll: Someone here will know

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Guest TurboSedan

i hate this goddamn car :evil:

 

looks like i get to pull all of the belt driven accesories off, balancer and timing cover and do it all over again tomarrow :?

 

my Haynes manual says to point BOTH the cam & crank sprockets at 12 o'clock (cam dowel pin at 9 o'clock). it doesn't get much easier than that but somehow i got it one tooth off :bash:

 

fucking car!

 

6mg of clonazepam to the rescue!

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This is from alldata, it shows the dowel at about the 1 o'clock, but I'd watch the marks on the sprockets instead of that.

 

REMOVAL

 

Remove timing cover. Refer to Timing Cover / Service and Repair.

Position No. 1 piston at TDC with marks on camshaft and crankshaft sprockets aligned, Fig. 8.

Remove camshaft sprocket and chain. If sprocket does not come off easily, a light blow on lower edge of sprocket should dislodge it.

Remove crankshaft sprocket.

Remove timing chain damper assembly bolts and damper.

 

cf1d5b21.jpg

 

 

INSTALLATION

 

Install timing chain damper assembly and bolts. Torque damper bolts to 18-24 Nm ( 13-18 ft. lbs. ) .

Install crankshaft sprocket.

Apply Molykote or equivalent to sprocket thrust surface.

Hold sprocket with chain hanging down and align marks on camshaft and crankshaft sprockets, Fig. 9.

Align dowel in camshaft with dowel hole in camshaft sprocket.

Draw camshaft sprocket onto camshaft using attaching bolts, then torque bolt to 20-27 Nm ( 15-20 ft. lbs. ) .

Lubricate timing chain with engine oil.

Install timing cover. Refer to Timing Cover / Service and Repair.

 

 

f4687725.jpg

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Guest TurboSedan

are those directions for a 3100?

 

INSTALLATION

 

Install timing chain damper assembly and bolts. Torque damper bolts to 18-24 Nm ( 13-18 ft. lbs. ) .

Install crankshaft sprocket.

Apply Molykote or equivalent to sprocket thrust surface.

Hold sprocket with chain hanging down and align marks on camshaft and crankshaft sprockets, Fig. 9.

Align dowel in camshaft with dowel hole in camshaft sprocket.

Draw camshaft sprocket onto camshaft using attaching bolts, then torque bolt to 20-27 Nm ( 15-20 ft. lbs. ) .

Lubricate timing chain with engine oil.

Install timing cover. Refer to Timing Cover / Service and Repair.

 

 

anyways that's exactly what i did; the marks on both sprockets were @ 12 o'clock when i installed the chain. the Haynes manual even showed a picture of the camshaft dowel @ 9 o'clock (regardless, with the cam dowel @ 9 o'clock the cam sprocket timing mark is @ the 12 o'clock posistion). i must not have looked at it closely enough and got it one tooth retarded or something....or maybe i moved one of the sprockets slightly during installation :bash:

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I did both at 12 and it runs great. It is possibly a tooth off, OR its 180 degrees off. There are other things that could be causing it though, I think I'd check to make sure you don't have a big vacuum leak or something first.

 

Shawn

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Guest TurboSedan

well i pulled the timing cover off and triple checked the timing marks and they are 100% spot on.

 

sooo....i have a trashed engine on my hands. my guess is that i actually did bend some valves when the timing chain broke. probably have some nice gouges in the pistons too.

 

i may part the car out soon....

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Guest TurboSedan
This might sound too basic, but double check the plug wires. For some reason I always screw them up on mine

 

i've triple checked those yesterday & today :( i haven't done a compression check yet, but a bent valve is really the only thing it could be....i will check the compression but i'm expecting at least one cylinder to be next to no psi...

 

the fate of the Cutlass is really up in the air right now...

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Guest TurboSedan

 

i may part the car out soon....

Nooo! Damn it!

 

oh i probably won't, i'm just frustrated as hell with it right now. i think i'm going to tuck it away in the garage and forget about it for awhile (out of site, out of mind lol).

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Hopefully the compression check turns out good. If not, you always have the TGP engine laying around just waiting to be reborne. If the 3.1 in there now is a bit trashed, you can probably sell it to recoup the costs of building the TGP engine...

 

Tim

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Guest TurboSedan
If not, you always have the TGP engine laying around just waiting to be reborne.

Tim

 

that's what i'd like to do; do it the right way from the ground up. i'd probably rebuild it with a stock GM or a very mild cam & .020 over Mahle pistons. i already have the TGP heads freshly rebuilt with a valve job (assuming the valve guides aren't damaged from the broken timing chain) and i already have a new Melling 95HV oil pump for it. i also have a brand new clutch kit & a choice of two 282's to put behind it :P

 

i already have the entire top end ready of course, all the turbo parts, everything is already cleaned etc. i just need to get the TGP shortblock rebuilt. i'm not sure what that will cost though and i don't have the ca$h at the moment unfortunately.

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Guest TurboSedan

ok i'm a complete & utter dumbass :oops: last night i was sitting watching TV when it occured to me that i didn't remember torquing any of the plenum bolts to spec!! so i go out to my car and sure enough, all of them were only finger tight :lol: so i torqued them all evenly to 216 in/lbs and started it up for a second or two. it was almost midnight and the car is LOUD with just the open dowpipe, so i couldn't really do much until this morning.

 

so this morning i gave it a fresh oil & filter change (lots of coolant dropped into the oil pan when i pulled the timing cover). well, i have GREAT oil pressure and the car runs wayyyyyyy better and smoother now! keep in mind though, the timing cover is still off the engine right now, as well as no water pump or harmonic balancer of course.

 

BUT - even though the engine sounds good when i rev it it shakes like a mofo at idle. could this be because the harmonic balancer is not installed? i'm starting to think that's the problem with the engine shaking at idle (as opposed to low compression ie. bent valves). otherwise the engine seems to run great. like i said, it sounds great when i rev it.

 

i pulled all of the spark plugs and i'm about to head out and do a compression check and that will tell me for sure weather a valve is bent or not. wish me luck!

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BUT - even though the engine sounds good when i rev it it shakes like a mofo at idle. could this be because the harmonic balancer is not installed? i'm starting to think that's the problem with the engine shaking at idle (as opposed to low compression ie. bent valves). otherwise the engine seems to run great. like i said, it sounds great when i rev it.

 

 

Yeah, that makes sense because what is a harmonice balancer supposed to do? It's supposed to balance!!!

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Guest TurboSedan

well the results are in and i'm afraid they are not good :(

 

Piston #1 = 140psi

 

Piston #2 = 0psi

 

Piston #3 =140psi

 

Pison #4 = 150psi

 

Piston #5 = 145psi

 

Piston #6 = 150psi

 

well at least the #2 piston is on the front bank :? it looks like i'm going to have to pull the upper & lower intake manifolds & cylinder head to inspect the damage in hole #2.

 

some questions:

 

- so obviously one of the valves is bent, i'm assuming the intake valve?

 

- would a bent valve mess up the cylinder head itself (valve guide or anything else)?

 

- and what kind of damage would the piston have done to it? would the piston more than likely have to be replaced or just nicked? (i guess i'll just have to pull the cylinder head & check...)

 

- is the 140-150psi readings on the rest of the cylinders acceptable?

 

thanks

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Compression variance should be no more than 10 percent.

 

Probably had around 180-190 new so its still very tight, I'm sure there is still cross hatch in the bores with no real signs of wear. If a piece part came off when the valve kissed the piston metal fragments could score and gouge up that cyl wall, hope not :wink:

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