Heads, valves and rocker issue

[Reim]

Hello Gbody genius’s-

Starting again getting my 1986 Monte SS engine L69 going once again. The project has been put on the back burner for a while.

I am having a problem getting the valves adjusted. We took the engine out and did the bottom end. Pistons and rings were fine with compression in the 180-190 range. Replaced the valve guides, lifters etc. The car had a pretty aggressive cam when we bought it and broke a few rockers previously so we replaced the cam with a milder 1104 cam.

Put the engine back in, adjusted the valves and some of the rockers are getting loose and begin to rattle a little. My son says at TDC tighten the valves tight then 1/2 turn? Is that correct? I read that these 305 do not like cams and that the pushrod holes need to wallowed (not doing this) out to use anything larger than a stock cam? No problem going back to a stock cam(my recommendation) but son wants the bigger cam. I know these 305’s are just not built for many mods and that with any engine many other engine mechanicals like heads should be done too to make them work right.

I just want the thing to run and drive. We are planning to drive the car with the 305 and replace it down the road. I hate to make this engine a boat anchor 😀. Are we doing something wrong…it cannot be this difficult? Suggestions, opinions and remarks please? Thanks!

 

[79 USA 1]

As far as the valve adjustment here is a link to a YouTube video from Ellison's Machine shop that I have used many times. Never had any issues with loose or tight valves with a hydraulic cam using this method.

 

[Reim]

As far as the valve adjustment here is a link to a YouTube video from Ellison's Machine shop that I have used many times. Never had any issues with loose or tight valves with a hydraulic cam using this method.

Thanks 79 USA….ahhh we did not used this Method. This makes all the sense in the world and might explain the issue we are having. We just did not do the 90 degree thing 8x.

Thanks man. I will post up the results. Then do a burnout. Nice.

 

[565bbchevy]

The car had a pretty aggressive cam when we bought it and broke a few rockers previously so we replaced the cam with a milder 1104 cam.

If you haven't already, I would check all of your pushrods for straightness before readjusting your valve lash again.

 

[Reim]

Thanks 79 USA….ahhh we did not used this Method. This makes all the sense in the world and might explain the issue we are having. We just did not do the 90 degree thing 8x.

Thanks man. I will post up the results. Then do a burnout. Nice.

My heads and lifters are in so I’ll do the same procedure and be really careful. Oil is in the lifters already so kind of stuck with that. Should still work. Thanks agai. Reim

 

[Reim]

If you haven't already, I would check all of your pushrods for straightness before readjusting your valve lash again.

The pushrods were straight when we assemble. When I spin them in the head I should be able to tell if they are still straight. i think the adjustment we did left them too loose not too tight I hope. I’ll post up results. Thanks man

 

[CopperNick]

The 305, and I have a couple of them, is what I call a small motor. You won't have much luck with a high lift cam but a longer duration cam that comes in at about the same lift but holds the valves open a little longer will give you some more bottom end to work with. They usually come described as "RV" cams for the application they typically fill but I have used both ISKY and ENGLE variants and liked what they did The power band on them is around 1500-5000 and they are done by 5500 at the most.

Just as a Q., here, are your rocker studs pressed or screw in? Pressed in studs can pull or rise out of their bosses under some kinds of high lift situations. Might be useful just to measure the length of the rocker stud that is visible just to make sure none have "risen" from the grave. It is possible to pin studs but that is a machine shop exercise.



Nick

 

[Supercharged111]

Thanks 79 USA….ahhh we did not used this Method. This makes all the sense in the world and might explain the issue we are having. We just did not do the 90 degree thing 8x.

Thanks man. I will post up the results. Then do a burnout. Nice.

I do 8 with #1 at TDC and the other 8 with #6 at TDC.

 

[Reim]

The 305, and I have a couple of them, is what I call a small motor. You won't have much luck with a high lift cam but a longer duration cam that comes in at about the same lift but holds the valves open a little longer will give you some more bottom end to work with. They usually come described as "RV" cams for the application they typically fill but I have used both ISKY and ENGLE variants and liked what they did The power band on them is around 1500-5000 and they are done by 5500 at the most.

Just as a Q., here, are your rocker studs pressed or screw in? Pressed in studs can pull or rise out of their bosses under some kinds of high lift situations. Might be useful just to measure the length of the rocker stud that is visible just to make sure none have "risen" from the grave. It is possible to pin studs but that is a machine shop exercise.



Nick

Ok Nick. I’ll check the studs. We did measure them since we saw the rockers loosening up.

Yeah, it was my opinion when my son put the new cam in to go with stock. These 305 are low pressure mild engines used to produce big torque to push heavy cars with the lowest emissions for the day. The previous owner had a really big cam in there and sounded good and had a lope but really was not powerful. Then it started busting rockers and we had to change the cam. We pulled the 305, changed seals and gaskets, bottom end and changed to the 1104 cam. Maybe the adjustment will tighten things up and all would be good.

We knew the motor was previously modified. We bought the car to resto it a little since the body was nice with no rust and the interior was good. If we can get the 305 working well and reinstall the A/C it will hopefully be a good weekend cruiser for now. Got long tubes and Xpipe true dual exaust on it now. UMI braces front and back, new ball joints, brakes and shocks. It drives nice.

Hopefully, we can get this 305 going well and drop a motor in it down the road. I think these recommendations will fix the valves. Long live the Gbody 😀

 

[79 USA 1]

My heads and lifters are in so I’ll do the same procedure and be really careful. Oil is in the lifters already so kind of stuck with that. Should still work. Thanks agai. Reim

Even with oil in the lifters this method works. I've used it after installing new cam shaft and lifter sets as well as after installing new oil seals. What is nice after setting them all to zero lash (Just touching) I normally go 1/2 turn on all and the adjustment seems dead nuts on. Worked real well for a neighbor and the 383 stroker in his Chevelle, he had 4 collapsed lifters that after we did the 1/2 turn past zero we ran a compression check and found the dead cylinders.

I'll be waiting on the burnout video!