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High mileage Big Block rocker arm wear
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1960fury
Posted 2021-01-02 4:45 PM (#607338)
Subject: High mileage Big Block rocker arm wear



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Some time ago I took the valve covers off of my engine and noticed, when the lifter is at the base circle of the cam, that there is a little free play in some push rods. The engine is a 340+K miles untouched, never rebuild 1960 (1959) 383 that still runs like a clock.
I hate to touch a perfectly running system, but if there is free play it probably means, that the dish or the seat of the pushrod hits the retaining clip in the lifter and I wonder how long this can last and I also wonder if a push rod can poke thru a stamped steel rocker? That would be a nightmare.
These OE rockers, despite their crude, primitive looks are excellent pieces and very rugged, but should I replace them, maybe with a set of adjustable roller rockers? They aren't much more expensive. I'm asking for some old-timers, expert advice here.
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wizard
Posted 2021-01-02 5:19 PM (#607339 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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I know that the pushrods actually can eat through the rocker arms Sid, BUT the case was a newly renovated engine with too tight valve guides that made the valve stem seiz. The first rocker arm was eaten through during a long road trip - the guy was lucky enough to find a spare rocker arm, but on his way home a second valve stem seized with the same result - holes in the rocker arm and bent push rods.
The solution, or better "quick-fix" was in his case to add a little transmission fluid in each full tank of gas until the valve stems was "runned-in".

Most probably in your case, it's a combination of wear; tappet bottons, valve stems and rocker arms. I think you should remove the rocker arms and inspect them for to see if they're worn and if so, replace at least the worn ones.

Of course, the roller rockers would be a good thing because then you can adjust the pushrods to the correct preload individually.
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1960fury
Posted 2021-01-02 6:23 PM (#607342 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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Thanks for your input Sven. If a valve stays closed when the engine runs at higher speeds, wouldn't this result in a catastrophic case of engine failure with broken rods and worse?
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wizard
Posted 2021-01-03 3:15 AM (#607351 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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The engine was a 383 and the valve stem problems occured at country road speed Sid. The only damage was the rocker arms and the pushrods. This indicates that the valves seized in the closed position, otherwise there would have been serious damage.
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22mafeja
Posted 2021-01-03 3:37 AM (#607352 - in reply to #607338)
Subject: RE: High mileage Big Block rocker arm wear


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If I was you Sid I would change both lifters and rockers for sure. And inspect the pushrods and the rocker axles.
If it hasn`t been opened it is the time now before it breaks. A total renovation would probably be the best
but that is only my opinion.
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wizard
Posted 2021-01-03 4:52 AM (#607353 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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First of all Sid;

Do you have any cold engine valve train clattering?
Do you have any working temperature engine valve train clattering?

If you can answer yes to cold engine and no to warm engine I wouldn't be worried.
If you can answer no to both, then no actual problem.

Should you have warm engine valve train clattering, then you should demount and check everything in the cylinder heads, valve train, lifters pushrods and cam.

If I dont add ZDDP when I change the oil, then I have cold engine valve train clattering from one or two lifters for the first 30-60 seconds - then it's gone. With ZDDP the clattering is gone until it's time to change the oil.

I changed the timing gears and chain a year ago (just to find out that it wasn't really neccesary) and I could see the cam lobes well and I could see no wear.

As you know, my engine has never been renovated (a part from above), high mileage and frequently "actively" driven
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1960fury
Posted 2021-01-03 9:14 AM (#607356 - in reply to #607353)
Subject: Re: High mileage Big Block rocker arm wear



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I have no unusual noises whatsoever, cold or hot, not from the valvetrain or other places. As I said, it runs like new and does not even smoke when cold. The only thing that shows the mileage is the blowby.
If I change the lifters I will have to change the cam as well, since after 61 years and 340+K miles I do not want to part them.

It sounds weird but when I replaced the intake with an aluminum one in 89, I noticed some residue on the cam lobes and when I pulled the intake again not that long ago, I expected the residue to be gone after 30 years of running with full synthetic oil, it wasn't and it looked just like I remembered. So I do not think I have much lifter or lobe wear.
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wizard
Posted 2021-01-03 9:41 AM (#607358 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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So, I do think that you're good "as is" Sid!

Yes, new lifters would mean new cam as well, but I'm most certain that you would have noticed a worn cam, with less performance.
The only "quick-fix" is adjustabe roller rocker arms.

With your care and maintenenece, the engine will keep on running. That said, meanwhile, it could be wise to get the needed parts and save them for later.
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samstrader
Posted 2021-01-03 3:24 PM (#607374 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear


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I have just spent years trying to get my rebuilt engine running right and still struggling. If you have 340 thousand miles on that engine and no engine noise, wouldn't it be better to leave it alone and not risk messing up something. Maybe just check to make sure you oil pressure is good and if not, change the oil pump but I would be afraid to mess with something running that good. Just my 2 cents base on bad experiences.

I'm glad your engine is that good actually. I never knew the older engines could run that long without a rebuild.
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1960fury
Posted 2021-01-03 4:49 PM (#607377 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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Sam, that is not my only Big Block. They all are very high mileage and run like new. I checked the oil pressure and it is exactly 25% over the stock pressure with a 25% + high pressure/volume MP oil pump (installed in the early 90s). Yes, I hate to touch it, but I still drive it all out from time to time and the fact, that the pushrod seats hit the retainers can't be a good thing. It can only get worse and the rockers are relatively cheap and easy to replace.

Edited by 1960fury 2021-01-03 4:51 PM
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22mafeja
Posted 2021-01-04 3:10 AM (#607392 - in reply to #607338)
Subject: RE: High mileage Big Block rocker arm wear


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I haven`t restored one car in my life and left the engine untouched.
I have had several with perfectly running engines but nevertheless I have at least honed or bored the cylinders and polished/machined the crank ,inspected/replaced the cam and always
replaced the lifters etc.
For me it would have been impossible to enjoy driving with an engine with half the waterpockets full of crud and most of all oil galleries full of oil crud/tar.
Don`t like that kind of gambling.
Just my opinion...

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wizard
Posted 2021-01-04 4:23 AM (#607394 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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So, Sid, if you haven't done it yet; turn the engine to the tdc firing position and check the eventual lash for each pushrod. Do this on all cylinders.
This will give you exact knowledge of the lash in all the pushrods as you can measure with a feeler gauge.

There might be some lifters that has excessive leakages - this will allow the lifter to be more easily compressed, but when the engine start with your good oil pressure, the lifter will work normally. This might explain why you don't have any valve train clattering when you run the engine, but you detect some lash when the engine is stopped and the lifters in the lowest position.

Any way, when installing and adjusting new lifters on for example a Pontiac, the lifters should be empty of oil, so, the spring will normally give enough resistance for to check the lash.
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1960fury
Posted 2021-01-04 9:26 AM (#607398 - in reply to #607392)
Subject: RE: High mileage Big Block rocker arm wear



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22mafeja - 2021-01-04 3:10 AM

I haven`t restored one car in my life and left the engine untouched.
I have had several with perfectly running engines but nevertheless I have at least honed or bored the cylinders and polished/machined the crank ,inspected/replaced the cam and always
replaced the lifters etc.
For me it would have been impossible to enjoy driving with an engine with half the waterpockets full of crud and most of all oil galleries full of oil crud/tar.
Don`t like that kind of gambling.
Just my opinion...



Well, I bought the car when I was a teenager, my very first car. I had no other option and never regreted it leaving it basicaly untouched. I did drive the car for many years daily, still do in summers, and I do not think any other person here, or anywhere else on the planet, still alive, drove a FL more distance than I did. Did I enjoy it? You bet, I did and I saw the "rebuild" engines from my buddys fail regularly (all GM's tough).

What makes you think my engine is "full of crud"? As I said, I drive it almost daily since 1988/89 and I'm not a slow poke. My car still sees 130+ mph regularly. What can your "rebuild" do? It wouldn't have survived if it was "full of crud" or if it would have seen a half hearted "rebuild", which is all what you can afford if you are a regular guy in Germany, where you have to pay $$$ hourly machine shop rates. I once requested a quote and they estimated around $7500 for a professionell rebuild. I'd rather buy another untouched 383 for that, or 2, as they knew how to build engines back then.
All the Big Block cars I imported and modified are still running fine today with basically untouched engines. My ex 61 Desoto coupe I sold with about 250K miles and received the same mods as my Fury, still goes easily 133 mph with the low compression 361. Of course I replaced the timing chain/gears on all cars.
Unfortunatly the hobby is full of ignorant "if its old, its got to be bad" people, that destroy needlessly originality.



Edited by 1960fury 2021-01-04 9:48 AM
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1960fury
Posted 2021-01-04 9:39 AM (#607399 - in reply to #607394)
Subject: Re: High mileage Big Block rocker arm wear



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wizard - 2021-01-04 4:23 AM

So, Sid, if you haven't done it yet; turn the engine to the tdc firing position and check the eventual lash for each pushrod. Do this on all cylinders.
This will give you exact knowledge of the lash in all the pushrods as you can measure with a feeler gauge.

There might be some lifters that has excessive leakages - this will allow the lifter to be more easily compressed, but when the engine start with your good oil pressure, the lifter will work normally. This might explain why you don't have any valve train clattering when you run the engine, but you detect some lash when the engine is stopped and the lifters in the lowest position.

Any way, when installing and adjusting new lifters on for example a Pontiac, the lifters should be empty of oil, so, the spring will normally give enough resistance for to check the lash.


Sven, the free play of the pushrods of course I noticed with the engine not running, without oil pressure There is a spring in the lifter that shouldn't allow any free play, if there is, it means the seat hits the retainer and oil pressure will not take care of it. Why it doesn't clatter (yet), I do not know. I'm worried about lifter damage and of course about what caused the play of the pushrods. My guess is rocker arm wear and rocker arm failure, a push rod poking thru, would be a nightmare at high rpms, that is when it mostly happens. This can destroy the block.
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wizard
Posted 2021-01-04 11:03 AM (#607401 - in reply to #607338)
Subject: Re: High mileage Big Block rocker arm wear



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I know the feeling Sid, I often scrutinize my car and it's function, perhaps too well. This was the case with the timing gears and chain - I was totally convienced that it had to be worn out. Ordered parts and measured the chain lash before I demounted the chain and gears. Mounted the new parts just to be dissapointed to find the same chain lash as with the old parts. Cam and bearings ok.

For you peace of mind, it seems that you must demount the intake manifold and check everything up.

When I renovated a Pontiac 350, I thought I checked everything, preload of lifters totally set according to the recommendations from Howard Cams which supplied the cam and lifters. Long story short; The owner lost oil pressure to the valve train after a month and crushed 8 pushrod ends like pressing on a cookie. I demounted everything and checked the oil supply to each lifter - all good, remounted the lifters and tried with a drill and adapter to get oil up through the new pushrods - nothing at all. Demounted everything again and this time also the lifters - there was residue from the grinding process inside all the lifters, this affected the lifters so that no oil could come up through the pushrods.

All lifters was super cleaned, oiled up, checked and remounted - after a few rotations of the drill, oil was supplied through all pushrods.

Of course Howard Cams never had a similar problem...... So, it goes to say - don't trust new parts - check everything.

Some time after, another friend told me that he had exactly the same problems on a Chevy engine.......
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57chizler
Posted 2021-01-04 1:11 PM (#607402 - in reply to #607399)
Subject: Re: High mileage Big Block rocker arm wear



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1960fury - 2021-01-04 6:39 AM

There is a spring in the lifter that shouldn't allow any free play, if there is, it means the seat hits the retainer and oil pressure will not take care of it.


When a new hydraulic lifter is put into service, the top disc in the lifter will be positioned a little below the retaining ring. After long years of service, a varnish ring will form in the gap between the disc and the retaining ring; this varnish ring might prevent the spring in the lifter from taking up the free play when the engine is off and the lifter bleeds down but hydraulic pressure in the lifter will seat the disc against the pushrod when the engine is running.

Just thinking out loud.
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22mafeja
Posted 2021-01-04 4:04 PM (#607404 - in reply to #607398)
Subject: RE: High mileage Big Block rocker arm wear


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I dare say Sid that every old unopened 50-60 v8 engine is full of oil crud at least under the intake in the lifter valley. It just is impossible to avoid caused by the low quality oil
used those days. The main oil galleries are always part clogged. I have restored about 25-30 v8 engines (I know, not so many) and every one have had the same issues.
Sometimes the crud is so tough that you have to pry it out of the corners with a chisel.
And the rearward freeze plugs are always rusted , sometimes through, because the crud levev inside is to half the plug.
I have never had to machine the deck or head surfaces ,totally wasted money on a vintage car driven a couple of thousands a year.(unless something bad has happened to the engine!)
I have never blown a head gasket.
Camshaft failure never.
Oil leaks always a little both engine and tranny.
Usually not done anything to the valvetrain except for cleaning , valve lapping , grinding of the rocker arm surfaces.
Always washed the engine parts myself .
My Desoto 361 renovation cost me:
1360 usd in parts ,pistons-all bearings-camshaft-lifters-camshaft drive-gasket kit-freeze plugs-oil pump -have surely forgot something (all in a kit from Falcon)
1100 usd machining bores to oversize , camshaft bearing assembly
And some fun work.
You just have to be careful with the machining shops...they sometimes put too tight clearances in the cylinders. They want to use 0.0015" (0,04mm) with hypereutectic ones
and then there might be overheating. I ordered the machining to 0.0025" and got a really quiet engine without overheating hell..
I must have been lucky not to destroy any of my engines....



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1960fury
Posted 2021-01-04 4:13 PM (#607406 - in reply to #607402)
Subject: Re: High mileage Big Block rocker arm wear



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57chizler - 2021-01-04 1:11 PM

1960fury - 2021-01-04 6:39 AM

There is a spring in the lifter that shouldn't allow any free play, if there is, it means the seat hits the retainer and oil pressure will not take care of it.


When a new hydraulic lifter is put into service, the top disc in the lifter will be positioned a little below the retaining ring. After long years of service, a varnish ring will form in the gap between the disc and the retaining ring; this varnish ring might prevent the spring in the lifter from taking up the free play when the engine is off and the lifter bleeds down but hydraulic pressure in the lifter will seat the disc against the pushrod when the engine is running.

Just thinking out loud.


Thanks for the info John!
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1960fury
Posted 2021-01-04 4:48 PM (#607408 - in reply to #607404)
Subject: RE: High mileage Big Block rocker arm wear



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22mafeja - 2021-01-04 4:04 PM


You just have to be careful with the machining shops...they sometimes put too tight clearances in the cylinders.


This what happened to a friend of mine with her 58 Cadillac. Money wasn't an issue for her and a shop with a very good reputation rebuild the engine... This ended up in court, I do not know the outcome, as we broke up before, but there are tons of nightmare storys about (old) engine rebuilds over here.

I don't have the money and the nerves and I HATE to let other people work on my cars. As a mechanic I know you can repair things in 3 ways: Bad, halfway ok so that it lasts for a ime and the way it should be done, perfect.
The latter you will never get from strangers working in a shop, as you pay them by hours. If you want it, you have to do it yourself and in case of an engine rebuild I do not have the machinery to do it, so I will stick with my original 383 and to be honest, I get a kick about the thought when I hear my engine start and coming alive the engine that performs so beautifully and still smokes most of the new cars, is the same engine that ran way, way back in the day on some California highway, build by Detroit workers, that are long gone. I know they smile upon my car and me from above
Now, that I know it stood the test of time and it doesn't seem to get tired, I wouldn't have it rebuild, even if I had the money. There is the excessive blowby, but I see no reason yet that it can't go to 500K or beyond.
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1960fury
Posted 2021-01-04 4:56 PM (#607409 - in reply to #607404)
Subject: RE: High mileage Big Block rocker arm wear



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22mafeja - 2021-01-04 4:04 PM

I dare say Sid that every old unopened 50-60 v8 engine is full of oil crud at least under the intake in the lifter valley.


When I bought it, it was 29 years old, not 60, and I have used only synthetic oil ever since. There was and is absolutely no crud in the lifter valley but there was about an inch of sludge in the oil pan, which I of course cleaned out when I straightened and modified the oil pan with baffles and a windage tray and up to this day, 31 years later, there is no sludge or crud in the pan or valley. The rockers however were covered with crust and still look the same, but that didn't keep my engine from running perfect up to this day.

Edited by 1960fury 2021-01-04 5:01 PM




(rocker.jpg)



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