Am I doing this wrong? 6 Cyl valve adjustment...

[Privatebrian43]

Hello Again, I've installed the CJP exhaust system and it worked out great. Was able to use the original hangers.
Now I've moved on to getting the engine to run a little smoother. Tested dry compression and it was (in order 1 to 6) 125,100,110,133,130,130). So I thought I would adjust the valve/rocker clearance. My Chiltons book says both intake and exhaust are 0.018", so I used a feeler gauge between the valve stem end and the rocker, adjusting the "nut" on the other end of the rocker until I got a snug gap. Compression improved to 130,138,165,140,136,135, but there was still some ticking/knocking.... now the rub - I was watching a Youtube vid on 170 cid valve adjustment on a 65 Falcon, and it was set to zero lash (push rod spins but won't move up or down, PLUS a half turn IN on the adjusting "nut"... Maybe this is specific to hydraulic lifters (?), I was using the procedure from my flat head jeep (42) that has tappets and no push rods... probably a mistake. So my question is - would a 66 170 CID Bronco engine have hyd lifters or solid?, and is the zero-lash+1/2 turn in correct, if so, why would Chiltons show a gap value?
Thanks for any comments,
Brian

 

[Privatebrian43]

Sorry the 165 psi shown on cyl 3 after adjustment should have been 135, I pressed the wrong key.
Brian

 

[DirtDonk]

Maybe this is specific to hydraulic lifters (?)

Yes, very specific to hydraulic lifters with pushrods.
A direct measurement like you were taking is done with either solid lifters, or those such as an overhead cam where the rocker arm rides directly on the cam lobe.

I was using the procedure from my flat head jeep (42) that has tappets and no push rods... probably a mistake.

Sounds right. Anything with no pushrods is a possible candidate for a valve clearance adjustment. But there are exceptions where they manufacturer has designed in some hydraulic mechanism. No pushrods, but still needs a preload adjustment rather than a clearance adjustment with a feeler gauge.

So my question is - would a 66 170 CID Bronco engine have hyd lifters or solid?

I'd answer that, but I'm not sure! Hoping to hear from the 170 experts (or in lieu of that, just going back and reading my books) to hear which way is correct for your engine.

...and is the zero-lash+1/2 turn in correct, if so, why would Chiltons show a gap value?

So you do have a book? Is it for the 170 in a Bronco specifically? If so, then I'd have to go with their method and adjust using a feeler gauge. Do your rockers have just single nuts on a center stud? Or are there adjuster screws with locking nuts out at the end of the rocker arms?
An adjuster screw with locking nut seems like a dead giveaway to me, for setting a gap.

Interested to hear what the experts say.

Paul

 

[DirtDonk]

And just for the fun of it, and for those of us that don't get to see many 170 sixes, do you have a couple of pics of the rocker area we could check out?

Thanks

paul

 

[Broncobowsher]

The Bronco 170 has solid lifters and needs clearance.
The car 170 has hydraulic lifters and needs preload.

You did everything correct except getting a second reference from a car source instead of a Bronco source.

 

[Rightpace]

https://fordsix.com/archive/www.classicinlines.com/ValveAdj.html

 

[Privatebrian43]

Thanks a lot guys! I don't have pics yet but I'll take some when I re-set the clearances. The link from Rightpace above calls for the adjustment to be done on a warm engine, I did it cold, as is recommended for the flat head jeep.
The adjustment nut is not near the center of the rocker, but at the end, directly over the push rod.
Yes, I have the Chilton's Bronco manual, covers 1966 to 1986. Not the greatest for detail, for example they don't give compression specs. They do show the compression ratio, at 9.1, so I calculated 9.1x14.7 = 134psi, using 14.7 psig for ambient air pressure.
Brian

 

[B RON CO]

Hi, when the engine has the adjustable rocker arms, with the friction fit screws over the push rod cups, it came with solid lifters from the factory.
It is possible someone changed the cam to a hydraulic lifter cam (probably not). You can test this by pushing down on the push rod. A solid lifter will not move. A hydraulic lifter will compress down a little.
When I adjust my lifters I like the feeler gauge to float on the valve, not grab.
The compression test is fine, your engine looks healthy. The book won't give a compression number. The compression number will go down as the rings and valves wear. Generally, as long as the cylinders are within 10 % of each other the engine should be smooth.
Good luck

 

[Privatebrian43]

Thank you B RON CO. I appreciate the help.
Brian