hi guys, ive done a search in the forumns for this, and i dont know what to do. i have a 91 RS with a 305. i run super unleaded gas always, so i dont think its poor fuel. the rockers are adjusted properly. and today i changed the header gaskets. im going nuts over this, and i have had my car parked for months trying to figure this out and to gather money to fix it. its LOUD and you can hear it inside the car. it does have an aftermarket cam and rockers, as well as MSD ignition w/6A box from previous owner (so im not sure exact size of cam).

its ticks at idle, and when throttle is increased. if its a lifter, can i just replace the lifters without replacing the cam too?
any advice on this subject would be greatly appreciated.

 

I would think that you might have to tighten down a rocker if it isn't the exhaust. But you checked that so I am at a loss here. It may be an exhaust leak in another location though, and since it increases proportionally with throttle, it is what I would think it is.

Also, your statement about "i run super so I know it's not poor fuel":

So many people have the misconception that Super fuel is "better" or "cleaner". The ONLY difference between regular and super is that super is harder to combust.

Higher compression engines need super because if they had a fuel that was EASY to combust, the pressure from the high compression would cause the fuel/air mixture to detonate before the plug could spark. Once the spark fires, you get ANOTHER detonation...commonly called a ping.

You are only running a fuel in your car that is harder to combust, not a fuel that is cleaner.

Edit: if it is REALLY loud...might be a rod knock?

 

Well it could be a fubared lifter or something. get a piece of hose and put one end to your eear and move the other end around the engine and see if you can narrow down where the noise is coming from.


Guitar is right about using high octane gas. Its useless on low compression motors, its harder to ignite and it also burns cooler. Your probably better off running 87, save the cash!

 

a knock that increases with rpm.. sounds engine or exhaust related, and I'm going to go with engine.

the first thing I'll say is this, check your ignition system. I had a friend with a dried/cracked plug wire and with an aftermarket MSD any wire/connection could be grounding out and arcing where it shouldn't be (against header, block, head, etc) the first thing I would check is all the plugs and wires, heck even check it in the dark, sometimes you can see something arcing where it shouldn't be. also really inspect the plugs, I've seen a plug with a cracked insulator (the white part sticking out) and it was arching out inside the plug boot so that cylinder was not firing.

is your engine a roller setup still?? how many miles on the new cam and were new roller lifters installed?? could be a collapsed lifter.. u should be able to tell by removing the valve covers and running the engine.. use a wrench on each rocker till you find the offending one (or more)

also check your collector gaskets where the headers meet the downpipe.

 

Are you running roller rockers? They're pretty noisy, and might even be hitting the valve covers.

 

Does the tick get louder with a load, or just with RPM? If it gets louder with a load, for instance going up a hill and pressing the throttle further it's probably exhaust related, if it only gets louder with RPM it's likely something more serious. hope this helps.

 

if its extremely loud, and kinda metal sounding check the dust shield on the bellhousing, i hit a big puddle and bent that so it barely hit th eend of the crank, thought my whole engine was gonna blow

 

thanks for all the quick responses! the previous owner installed the cam, so im not sure on the specs. im sure its just an upgraded version of the stock type(hydraulic, right?)
i didnt think of looking at the plugs/wires, but i will this weekend. im just ready to pull out my hair with this problem. i will run some fuel cleaner through there too(any suggestions on what brand fuel cleaner?)

 

Seafoam works for me, be sure to follow the directions and let the motor suck some in through the vacuum ports.

 

I am running bosch injectors and edelbrock runners on mine. The injectors are louder than stock to start with, and then two of them are pressed up against the runners (larger size) and the ticking of the injectors is amplified by the aluminum runners/heads and sounds just like a misadjusted set of rockers. FYI

 

i have a ebdelbrock 4bbl carb

 

did you check your ignition system and all plugs and wires, etc?

 

no 'cause it was raining today and yesterday. but i will!

 

drove car to the gas station up the road today because it was on "E". the car was running like crap, still ticking loud, and oil pressure was between 15-20. bad oil pump maybe ?