Skip to main content ↑ ↓
Topic: Rocker adjustment.... (Read 28274 times) previous topic - next topic

Rocker adjustment....

Reply #30 –
If you check with a vacuum gauge your engine more than likely won't have a reading of 18-20" vacuum at idle. Because it's got a bigger than stock cam it's going to read lower. Mine reads about 17" of vacuum at a 700rpm hot idle. The stock 5.0 HO in my Mark VII reads about 18" of vacuum at idle. I wouldn't be surprised if your combo made 15" or so of vacuum at idle.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Rocker adjustment....

Reply #31 –
Last time I checked I made 18" @ 750 RPM. 

Custom cam....
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Rocker adjustment....

Reply #32 –
Isn't 16-18 the normal range for stock engines of most vehicles? I'll have to go home and check mine - I don't remember what I get. I especially don't think I've checked with the current heads.

My daily driver pulls over 20 inches at idle. I believe most people with that car and have gauges report 20-22 inches - on the higher side at sea level.
1988 Thunderbird Sport

Rocker adjustment....

Reply #33 –
my car was idling at 900 to 950 today. It seemed relatively happy with that. The rockers do chatter a bit too much for me. This weekend, I will try to re-adjust the rockers and check the rest of it all. Dang.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #34 –
Tomorrow morning, I'm readjusting the rockers. Like Ed Curtis told me to do. (Like I had them). I do have a question, i have HEARD that the polylocks should be from 1/4 to 1 complete turn then lock them. Is it possible I may need a bit more than half a turn? Maybe 3/4 turn then lock them?
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #35 –
NOPE the amount of turns from ZERO lash makes no difference. All you are doing with the extra turn from ZERO ios adding more Pre Load. And this can be anywhere from ZERO to one turn.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

Rocker adjustment....

Reply #36 –
Quote from: vinnietbird;439735
Tomorrow morning, I'm readjusting the rockers. Like Ed Curtis told me to do. (Like I had them). I do have a question, i have HEARD that the polylocks should be from 1/4 to 1 complete turn then lock them. Is it possible I may need a bit more than half a turn? Maybe 3/4 turn then lock them?

Not sure what you're asking. The entire nut should spin to zero-lash. Then turn the nut another 1/4-1/2 inch. At that point, hold the nut with a wrench and tighten the set-screw until it pops.

All the 1/4 to 1 turn is doing is adding preload to the lifter. 1-turn would be too much preload - you "could" get the valve stuck open once the lifter fills with oil. I doubt you wish to be burning your valves. Even 3/4 turn I'd be worried about - I'm paranoid about burnt valves. 3/8 a turn has worked fine for me on my TW170 heads.

If you don't like the noise, try different rocker arms. You could also try different hydraulic lifters, but my high-energy ones are no louder or quieter than the stock-like FMS units. All of my valve train noise in the past was due to my Crane Energizer rocker arms - new rocker arms, no more loud noise. The valvetrain now is no louder than anything else the car is doing - likely pretty close to stock stamped units. My previous rocker arms had me worried for years (and spent a lot of money trying to resolve it) as I it was louder than anything else on the vehicle, other than the stereo. Not "sewing-machine" loud - my valvetrain sounded closer to solid lifters. I tried more preload, different lifters, pushrods, and oil. I reused the lifters in my new setup, but it is SO much quieter with the different rocker arms.

During all of the noise issues I had, the valve train geometry looked fine with a sharpie test. It ran for over 10k miles as a daily driver, until the car lost daily-driver duty, I swapped heads, and rocker arms.
1988 Thunderbird Sport

Rocker adjustment....

Reply #37 –
Thanks guys. The rockers will go to half a turn then. The spark plugs look like the car may be running a bit lean. Gotta figure that out as well. I can drive regular all day with clean exhaust (no smoke....), then if I floor it, smoke.

I'd try a different set of rockers if I can find a set to try at a decent price. My Scorpions are brand new. I still owe Kitz for the remainder of the cost of the heads, so my budget is small.

I pulled the upper intake and valve covers this evening (going to adjust the rockers in the morning), and two of the 16 rockers seemed tighter than the others. Some rockes have a bit of side to side movement, but no up and down movement.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #38 –
Quote from: vinnietbird;439747
Thanks guys. The rockers will go to half a turn then. The spark plugs look like the car may be running a bit lean. Gotta figure that out as well. I can drive regular all day with clean exhaust (no smoke....), then if I floor it, smoke.

I'd try a different set of rockers if I can find a set to try at a decent price. My Scorpions are brand new. I still owe Kitz for the remainder of the cost of the heads, so my budget is small.

I pulled the upper intake and valve covers this evening (going to adjust the rockers in the morning), and two of the 16 rockers seemed tighter than the others. Some rockes have a bit of side to side movement, but no up and down movement.

The oil will still allow some twisting movement by hand. How long was the car run, and at what rpm's? Certain cylinders will take longer to oil up. When running, some may be like a fountain while others only weep.

As long as they are tightened on the base-circle of the cam, with 1/2 a turn on the stud for preload, and they are locked correctly (you should hear a pop when they get tight enough), the valvetrain should be fine. Obviously, correct pushrod length still matters. I had my heads shaved a lot when I got them, to go from 64cc to 54cc chambers, and went shorter pushrod after measuring with a solid lifter.
1988 Thunderbird Sport

Rocker adjustment....

Reply #39 –
Thanks. I'll report in tomorrow after I'm finished. I'm also re-installing my Kirban AFP regulator. It was always good on the car and it as pulled when I replaced the fuel rails some time ago. It can't hurt.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #40 –
As far as I can tell, my vacuum looks mostly like #3 on this chart....



http://sbftech.com/index.php?topic=3020.0

It's reading almost 15 psi on the vacuum gauge.

Fuel pressure on the gauge is showing 30 with the vacuum hooked up.

Idle is about 950 at this time.

Timing is now set to 18 degrees.

Spark plug gap is .050

Taking it for a test drive in just a bit.

Any input from you guys is more than welcome and appreciated.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #41 –
Drove the car, idle was at....gulp....1500 after I reset the timing. Fuel pressure is at 28 with the car running and the vacuum line hooked up, 36 psi without the vacuum line. I think it needs a wee bit more.

I'll recheck the vacuum tomorrow, and will also bump up the fuel pressure as well. TPS is set at .95. I did the base idle reset, idle is a lopey 900 right now at 18 degrees. Plugs look really really clean, no smoke on acceleration. I THINK I MAY be closing in on a resting point.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #42 –
Set the fuel pressure to 39-40psi with the vacuum line disconnected and you should be good to go. I'm betting the low fuel pressure is what caused the popping and hesitation issues. The lower fuel pressure was probably making the car run a bit lean. I have 40psi of fuel pressure on my car with the vacuum line disconnected. I have a stock replacement Motorcraft fuel pressure regulator. The computer ends up tuning around any fuel pressure change above or below the stock 39-40psi setting. As far as roller rocker noise this is what my car sounds like. It's about 1/2 turn after zero lash with a 700rpm hot idle.
http://m.youtube.com/watch?v=ayd1Hc0TePc
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Rocker adjustment....

Reply #43 –
YES!!! THAT noise sounds like mine right now. LOL. A LOT worse before I readjusted the rockers today. I was happy with it after the adjusting. Especially after the last week of crazy chatter. LOL.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Rocker adjustment....

Reply #44 –
Quote from: vinnietbird;439783
YES!!! THAT noise sounds like mine right now. LOL. A LOT worse before I readjusted the rockers today. I was happy with it after the adjusting. Especially after the last week of crazy chatter. LOL.


The sound of performance! :hick:
1988 Thunderbird Sport