- May 3, 2007
- 17
- 0
- 0
I just bought a 90 lx with a fresh 306 in it. The car was running perfect and had the following upgrades already done to the engine:
Trick flow intake
Trick flow stage 1 cam (499,510 lift)
1.6 fms roller rockers
stock heads
So after driving it like this for a few weeks I decided to put a set of edelbrock performer rpm heads on it. They are the ones with the small 1.90 intake valve. I tore the engine down myself and put felpro 1011-2 head gaskets on. Put felpro 1250 intake gaskets on and made sure everything was in perfect shape. I added the heads with a set of comp cams pro magnum 1.6 ratio roller rockers and stock length pushrods. Well I adjusted the valves the same way I always do by bumping the engine over and adjusting the intake valve when the exhaust starts to open and adjusting the exhaust when the intake valve starts to close. Well it was time to fire it up and it fired right up but the rockers sounded way too loose. They were clacking and the engine didn't want to rev up at all. Studdering and not much vacuum unless you revved it up around 5,000 or so. So I readjusted them again and the same thing happened.
So I ended up changing the roller rockers to harland sharp 1.6's today and readjusted them the same way again. This time they seemed too tight and the engine would do nothing below 5,000rpms again. So I went back and loosened them all 1/2 turn and now the engine will rev from around 2,500rpms and up perfect. But below that and it won't run at all basically. Missing and studdering real bad. But as soon as the rpms hit around 2,500 then the engine revs up perfect and nice and quick like it should. So I loosened them up again and now they are too loose and the engine still only runs at around 2,500 and up. I'm completely stumped as to what is wrong unless I have the wrong length pushrods. I ordered a set of FMS stock length hardened pushrods because that's what I was told to use. Where did I go wrong guys? I have went over the whole engine and everything is fine. The distributor is on the right tooth. The timing is set at 10* initial. No leaks of any sort. No loose vacuum connections. 35psi oil pressure at around idle and 42lbs of fuel pressure at idle. The engine is beyond sluggish and doesn't want to rev until around 2,500rpms......Please help!!!
Trick flow intake
Trick flow stage 1 cam (499,510 lift)
1.6 fms roller rockers
stock heads
So after driving it like this for a few weeks I decided to put a set of edelbrock performer rpm heads on it. They are the ones with the small 1.90 intake valve. I tore the engine down myself and put felpro 1011-2 head gaskets on. Put felpro 1250 intake gaskets on and made sure everything was in perfect shape. I added the heads with a set of comp cams pro magnum 1.6 ratio roller rockers and stock length pushrods. Well I adjusted the valves the same way I always do by bumping the engine over and adjusting the intake valve when the exhaust starts to open and adjusting the exhaust when the intake valve starts to close. Well it was time to fire it up and it fired right up but the rockers sounded way too loose. They were clacking and the engine didn't want to rev up at all. Studdering and not much vacuum unless you revved it up around 5,000 or so. So I readjusted them again and the same thing happened.
So I ended up changing the roller rockers to harland sharp 1.6's today and readjusted them the same way again. This time they seemed too tight and the engine would do nothing below 5,000rpms again. So I went back and loosened them all 1/2 turn and now the engine will rev from around 2,500rpms and up perfect. But below that and it won't run at all basically. Missing and studdering real bad. But as soon as the rpms hit around 2,500 then the engine revs up perfect and nice and quick like it should. So I loosened them up again and now they are too loose and the engine still only runs at around 2,500 and up. I'm completely stumped as to what is wrong unless I have the wrong length pushrods. I ordered a set of FMS stock length hardened pushrods because that's what I was told to use. Where did I go wrong guys? I have went over the whole engine and everything is fine. The distributor is on the right tooth. The timing is set at 10* initial. No leaks of any sort. No loose vacuum connections. 35psi oil pressure at around idle and 42lbs of fuel pressure at idle. The engine is beyond sluggish and doesn't want to rev until around 2,500rpms......Please help!!!