Hydraulic lifters/pushrods

[mach1dave]

My '71 Mach 1 (351c 2v) was parked up for nearly 8 years, although I regularly started it and ran it for 5/10 mins, just to keep the internals coated in oil, also changed the oil filter once a year. Now it's back on the road, it's not running 100%. Got a little puff of smoke from the left hand exhaust, when warmed up, nothing from the right one. Checked everything, all seems good, so am suspecting the lifters/pushrods, (may account for the low oil pressure at idle as well?). Had a sticky one for definite before she was 'put away' so am going to change them and the rods as a matter of course. Any advice/pitfuls to look out for while doing the job? Do I soak the new lifters in oil prior to installation? What is the correct way to torque down the rockers - as they are just bolted down to the stop, unlike 'adjustable' tappets where you have to set the 'gaps' in order (when both valves are closed), does the engine need turning and each rocker bolted down in a specific order or it just doesn't matter? Most of my previous cars had solid liters so not too hot on the hydraulic ones! Lastly, apart from the lifters and pushrods, anything else I should consider changing while the manifold is off?
Any help/advice will be greatly appreciated!
Thanks!

 

[Hemikiller]

Puff of smoke out the exhaust on startup is usually just valve seals. Pull a rocker cover on the side that smokes and take a look. You'll often see bits of the seals lying in the head, or inside the valve springs.

A sticky lifter will tick, that's about it. Normally it'll resolve itself if you drive the car more. I've used a half quart of ATF mixed in with the engine oil to resolve lifter ticks in the past. It works well to dissolve deposits. Clevelands are known to bend pushrods, which can also cause a tick. You can check them by spinning each pushrod between your fingers. If the rocker moves side to side, the pushrod is bent.

Your rockers are bolt down style from the factory. Torque spec for the bolt is 18-25 ft/lbs.

FWIW, I'd do everything I could to avoid having to change the lifters. Lots of issues with today's lifters failing and not being machined properly, or poor metallurgy.

 

[mach1dave]

HK, thanks for the advice/heads up, makes sense it may be a pushrod.

 

[71ProjectJunk]

How low is the oil pressure at idle?

 

[mach1dave]

How low is the oil pressure at idle?

Hi. At idle when hot, the needle on the original dash oil gauge is literaly at lowest point on gauge. If I idle it out of gear, about 950rpm, pressure picks up slightly, maybe an 1/8th inch from lower mark on gauge.

 

[Hemikiller]

Hi. At idle when hot, the needle on the original dash oil gauge is literaly at lowest point on gauge. If I idle it out of gear, about 950rpm, pressure picks up slightly, maybe an 1/8th inch from lower mark on gauge.

Remove the factory sender and install a mechanical gauge to get an actual number.

 

[71ProjectJunk]

Yes, that would give one a real number to work with.

 

[mach1dave]

OK guys, I will check with a mechanical gauge before any thing else...

 

[basstrix]

Something that happens with an engine that's been sitting for a long time is, as hemikiller noted...the valve stem seals dry out, crack, and fall off.... You can often find bits and pieces in the oil drainback holes in the heads....unfortunately, there may be a bunch of them already down in the pan and pulled into the oil pump pickup. Let's hope your mechanical gauge test has good results!

 

[71ProjectJunk]

I don't even think that they have to sit for too long for those old valve stem seals to fall off and start blocking the oil pickup. A bunch of late 60's early 70's engines that I opened as early as the mid-80's had the valve stem seals, that had dried off and broken, in the oil pickup. At the time, some of those cars and engines we are little as 12 years old...

 

[basstrix]

I don't even think that they have to sit for too long for those old valve stem seals to fall off and start blocking the oil pickup. A bunch of late 60's early 70's engines that I opened as early as the mid-80's had the valve stem seals, that had dried off and broken, in the oil pickup. At the time, some of those cars and engines we are little as 12 years old...

Yeah, I think the brand/quality of the original seal plays a role. I came across some seals I had in storage since the late 80's....one pack of them cracked and falling to pieces, another felt just fine. I think the cracked ones came with one of those old cheap detroit gasket sets, while the ones intact were in a fel-pro kit.

 

[mach1dave]

Thanks guys, will pull rocker covers and/or oil pan to check for pieces. Is it possible to change the valve stem seals without pulling the heads?

 

[boilermaster]

Yes it can be done mach1 dave.
You will need some specialty tools and some special precautions.
should take about 2 hours per side.
You will need a valve spring compressor, either OEM lever type or handwheel adjustable type or both.
you should have a strong stick magnet to catch the valve keepers when removing and installing springs.
engine assembly lube for keeping the keepers where they belong during assembly and to lube the seal during install onto the valve.
You (may) want a compression air hold fitting to use with shop air to hold the valve up while the spring is being removed and installed.
also a remote underhood start button can be helpfull.
You will probably get differing opinions on how to do this job, but I prefer not to pressurize the cylinder when removing and installing the springs, instead I like to remove only the rockers on one cylinder at a time and bring that piston to TDC on the compression stroke to hold the valve from dropping into the cylinder (an air hold to the cylinder will force the piston to the bottom of it's bore)
I also only rotate the engine by hand to bring the pistons to TDC.
As those broken valve stem seals can find a way to the oil pan, so can the the retainer keepers, so cover the oil drains in the block and heads and in the intake ports if the intake manifold is off while doing this work.
by asking if this work can be done with the heads still on the engine tells me you have never done this before.
If you are not 100% confident in yourself, have someone else do the job, as failure can be catastrophic, bare minimum, watch a few video's and consult a ford shop manual.

 

[mach1dave]

Thanks Boilermaster, very informative advice. You're right, not done this before, only with the heads off. Am usually pretty confident at most jobs I encounter, but will have a think about this one, and possibly pull the heads......!
Thanks again for the write up.

 

[basstrix]

Boilermaker gave good instructs...I'm one that prefers to use compressed air...still do it one cylinder at a time, but much easier for me to get the new seal over the stem and hold the valve up while putting spring/retainer/keepers back in. The compressed cylinder holds the valves up tight.

 

[boilermaster]

mach1dave,
basstrix method is closer to what the shop manual states.
Granted when I install the oil seal on the valve, the valve is probably going to be resting on the piston, then when the seal is installed, you can lift the valve to the seated position while holding the seal down and the valve will then stay in place while one re-installs the spring and retainer assembly.
One advantage to doing the job without air is that you can judge the amount of valve guide/ valve stem wear by moving/ wiggle the valve to judge (could also measure) the valve guide to stem clearance.
Yea, you cannot do anything about excessive clearance with the heads on but at least you will have an idea where you stand.
Then there is the whole thing about what seals to buy.

 

[Hemikiller]

I've used three methods - air, no air and piston at TDC, no air and fill cylinder with a length of rope and bring to TDC. No air and rope method is "safest" - if you will - for the shade tree guy.

 

[boilermaster]

Just throwing this out there,
OTC4573 is my go to tool for doing valve seals on the car, it will work well on single springs or single with a damper spring.

 

[boilermaster]

According to the 1972 engine manual T70P-6049-a is the 2 piece ford tool.

 

[71ProjectJunk]

I agree with Hemikiller that the rope method is safest, plus you do not need any specialty tools. Depending on how long it has been since that engine has been apart, it may not be a bad idea to pull the heads and do it with the heads off. Gives you a good chance to clean the heads and valves well and put everything back together nice and clean. If that engine has never been apart and has been running since 1971 you will be surprised as to how much carbon buildup will be behind the valves and inside the intake and exhaust ports and the combustion chambers, enough to affect the performance of the engine.