Heads or Cam?

[dan_iowa76]

Hey all:

Just mounted some machined stock heads for my '88 mustang. They were done by a reputable shop- ported and polished, with oversized valves and converted to stud mount. Also just put in a B-Cam and converted to MAF just to complicate things are much as humanly possible. Car is running like crap- I checked the MAF computer, put in new injectors, and tested the harness for continuity. Also timed it several times and found that 16* advanced works best. Anyhow, it runs like shit so I did a compression test today and here are the results:

1-150
2-0
3-0
4-150
5-120
6-0
7-150
8-140

Car never makes any bad noises- just missing on 3 cylendars big time. Believe it or not, it actually does have decent power at hight rpm. Why would these valves be hung? If those oversized valves hit the pistons, would it be audible? Retorque rockers, take the heads off and look, drive over a cliff? V/r

[Dark_5.0]

You have your valves set too tight which is hanging the valve open and resulting in zero compression.

Tighten the rocker until there is no up and down movement in the pushrod and then go 1/2 a turn

When the intake valve starts to close set the exhaust valve.

When the exhaust valve starts to open set the intake valve.

You can thank me later,

[rwhite65]

Originally Posted by Dark_5.0

You have your valves set too tight which is hanging the valve open and resulting in zero compression.

Tighten the rocker until there is no up and down movement in the pushrod and then go 1/2 a turn

When the intake valve starts to close set the exhaust valve.

When the exhaust valve starts to open set the intake valve.

You can thank me later,

I agree, let us know the results

[dan_iowa76]

Will do.......the only thing that concerns me now is that someone suggested that the "pistons HAVE to be altered due to the larger diameter valves." Is that likely? The guy that sold me the heads had done that type mod before on cars like mine and he assured me that all I had to do was throw them on the car and all would be well. Valves striking pistons?

Also, just to double check, the way suggested to adjust the valves will work for stud mount, right? I am heading to the garage right now!! V/r

[dan_iowa76]

Thanks Dark_5.0.

Christmas is a bad time to be doing this stuff- what timing. Anyways, maybe someone can help just a teents more.

Just got back from the garage. Adjusted the rockers like you said Dark, and did it all in firing order- not sure that makes a difference when all I am doing is feeling for rods to go up or down. I will let you know if that was the trick- does anyone know if I can do a compression test with the valve covers and plenumn still off without messing anything up? Never did it that way before, but I don't see why not. Thanks again, and Merry Christmas. Dan.

[dan_iowa76]

Wow, thanks. I re-adjusted the rockers and before throwing the covers and plenumn back on, I did a compression check and couldn't believe my eyes. Everything was 155 plus or minus 5!! At that point, I couldn't get the car put back together fast enough to start it up. Low and behold, all 8 are hitting now. Thanks a million!! I guess the lifters needed some time to settle in even though I pumped the hell out of them while submerged in oil. Just got to fine tune now. Can't thank you enough. Merry Christmas. Maybe now I can have some holiday cheer!! ...........and by cheer I mean beer V/r

[~The Jester~]

WTG Dark! Nailed that one right from the get go.

Glad it worked out for ya Dan!

[Dark_5.0]

Originally Posted by dan_iowa76

Wow, thanks. I re-adjusted the rockers and before throwing the covers and plenumn back on, I did a compression check and couldn't believe my eyes. Everything was 155 plus or minus 5!! At that point, I couldn't get the car put back together fast enough to start it up. Low and behold, all 8 are hitting now. Thanks a million!! I guess the lifters needed some time to settle in even though I pumped the hell out of them while submerged in oil. Just got to fine tune now. Can't thank you enough. Merry Christmas. Maybe now I can have some holiday cheer!! ...........and by cheer I mean beer V/r

Glad I could help

[dan_iowa76]

Thanks, thanks, and more thanks, the car is tested and running great. Have some good feedback for ya'll- hopefully you find it useful. ....The intake valves are 1.9 and the exhaust are 1.5 or 1.6. Any larger, like 2.1, and the pistons would more than likely require some work. Also, there is plenty of clearance from valve to piston with a b-cam. Getting a larger cam could cause problems expecially if you are going for something crazy. The guy that did the heads for me is very reputable and has put hundreds of heads with valves like mine on mustangs and with no clearance issues. Finally, don't know why we had such dire results after carefully adjusting the rockers on the first time. I can only assume that it had something to do with the lifters needing break-in. 2d time was a charm!! V/r

[~The Jester~]

Originally Posted by dan_iowa76

Thanks, thanks, and more thanks, the car is tested and running great. Have some good feedback for ya'll- hopefully you find it useful. ....The intake valves are 1.9 and the exhaust are 1.5 or 1.6. Any larger, like 2.1, and the pistons would more than likely require some work. Also, there is plenty of clearance from valve to piston with a b-cam. Getting a larger cam could cause problems expecially if you are going for something crazy. The guy that did the heads for me is very reputable and has put hundreds of heads with valves like mine on mustangs and with no clearance issues. Finally, don't know why we had such dire results after carefully adjusting the rockers on the first time. I can only assume that it had something to do with the lifters needing break-in. 2d time was a charm!! V/r

I just gotta tell ya how important what Dark5.0 was talking about. In ONE summer I replaced 24 valves! Think about it, there's only 16 in there!

But, that's one of the reasons we make the pony's we do. Run it up to "melt down", and then come back 1/4 turn. LOL

Glad it worked out for you!!!!

[dan_iowa76]

Still runs great, just went through and readjusted the rockers again because they sounded a little loose like a sewing machine sounds. Noticed that some of the lifters are springy and some are solid. What does that tell me? Do I adjust the rockers differently for springy lifters than solid feeling lifters? Please reply, almost there!!! Thanks, dan

[~The Jester~]

They should all feel "solid". The springy ones are either weak, or haven't pumped up with oil yet. The longer you run it, the better it'll get. Make sure you adjust them ALL again after the car runs for 15-20 minutes with good oil pressure. It's a royal pain, but well worth it.