Timmie

Ok,my 91 camaro had a 3.4 95 camaro block with a top intake of a 3.1 camaro

we have replaced the camshaft, timing chain ( comp cams 260H kit ) and heads ( new rebuild heads shaven 0,5mm )
new spark plugs, new dizzie, new cap.
now we rebuild the block and we can't seem to find ignition timing.
it tried a couple of times to fire but to no avail.
we have iginition on al spark plugs, and we do smell fuel. but it just wont fire op. at this moment our only guess is that maybe the fuel injectors aren't deep enough in there holes, creating a vacuumleak.

other thing that I want to ask is, dus al the injectors fire on the same time on these engines or does only the injector with the exhaust port op fire.
in both cases, how does the engine know what injector to fire or at what time....

need some serious help here. ( brown wire has binn disconnected to set timing )

zs&tas

I believe these are batch fire split right/left banks, do you have compression ? are the plugs gaped right ? is the dizzy in the right place ?
just a few things, hope you get there !

Timmie

new AC delco original spark plugs
timing needs to be rechecked. we where not able to find it.
btw, is it normal dat you can turn the v6 engine with just a wrench on the crankcase. I mean you feel that it feels though turning it around completely build up, but its not like its getting so much compression that you cant turn it around anymore.

ex-x-fire

If you set the timing chain marks dot to dot & put the distributor in pointing at #1 spark plug wire, your 180 out.

Timmie

we cant see the timing chain anymore, ( and I'm gonna take of the timing cover )

the valves I can check ( if both are closed and the engine is at TDC the dizzie should be on 7o clock with 10 degrees of pre ignition.

zs&tas

mine has allways turned fully built relatively easily mate

Timmie

thats a relief, because I had heard someone with a v8 say that after 1 to 2 turns on his blok, you cant turn to block anymore because of compression. he even destroyed a wrech on it.

zs&tas

im guessing he may have had a bigger issue, like the chain was out and valaves were touching pistons, or he was week ? lol dunnno but ive had a few sbc and all turned no probs !

Six_Shooter

iTrader: (2)

The only engines I've had an issue turning by hand either had an issue, or were performance engines that had very high static compression.

The 2.8/3.1 fire all injectors at the same time.

It sounds like your timg is off. Set the engine TDC #1 compresion stroke, then verify that the rotor is pointing at the #1 plug terminal or just before.

In some cases, especially where I have to set large amounts of base/total timing, I will set the engine at that amount TDC, say 30 degrees BTDC, then set the rotor to point at the plug terminal. Stock or stock type engines don't usually require this technique though.

Timmie

ok extra troubles, and this aint good.
first I dont have compression on 1 complete bank of cilinders. with other words, something is wrong here ( yet the engine would still have to try to start up even if its only on 3 cilinders )

second, on of my valves stays down. and this really cant be good.
how do I fix this, can I just put in a new valve, can I get the original valve to work again?

I just hope I dont kill the cam break in period because we already tried it to start so many times last night without any succes. god i'm getting desperate

Six_Shooter

iTrader: (2)

You're pulling it back apart, no way around it.

You either have a bad head gasket, or bent a valve in all of the cylinders in that bank.

If one is hanging open, there's a good chance that it's made contact with the piston and bent. The piston could also be be damaged.

I'm having a similar issue with a 1959 Ford 352. I rebuilt it over a year ago, finally got around to starting it last week, 3 cylinders just wouldn't come alive, and had large amount of leak down, yet tear the engine apart and have found nothing obvious so far. At least you know there's a problem with one valve, now you just have to find the problem(s) with the other two problematic cyilinders.

Edwardgp

Sorry but I am believing it might have something to do with the valve timing.

Six_Shooter

iTrader: (2)

Possible, when there's a stuck valve, that could be due to being bent. Either way, it has to come apart.

Timmie

thought it was a non interference engine.
I really hope it didnt hit the piston, thank god the engine never fired.
so it isn't that the piston has hit the valve with full force ( if it hit it )
anyway, I ordered some new valves from rockauto. but I REALLY hope there aint nothing wrong with my cam.


peeps, pls pray to the thirdgen god for me.

ex-x-fire

Remove all the spark plugs & loosen all the rockers, pump compressed air into the cylinders (use a compression tester w/ the schrader valve removed), if the valves are sealing then the engine will rotate briefly. If not you hear air escaping at the intake or exhaust.

Timmie

we are gonna put the old heads back on the car.
ofcours they are not shaven 0,5mm
but they are in good condition.

RBob

iTrader: (1)

Note that the rocker arms need to be lashed on these engine. Not torqued to a specific valve like most of the books say.

Zero lash the rocker (jiggle pushrod up & down) then 3/4 additional turn.

RBob.

Timmie

update,
I took the heads of, put new valves in them and polished them into there seats.
reinstalled the heads etc, everything seems to work fine. But looks like I dont have enough vacuum to make my heater vents go the another stand except front window. ( unless at around 1200 or when im slowly revving it. ( creating a bit of vacuum ))

I also noticed that im missing the vacuum orbb of power.
gonna need to find another 1.