350 upper rebuilt now very very loud engine knock

[ryanbenn1207]

Engine- 350 1975 era

I just rebuilt this engine due to stuck lifters, I replaced the lifters camshaft and timing gear and chain, I was working on this with my mechanic friend in his shop, well i came back one day after it was all reassembled to find he had adjusted the rocker arms without me there, this worried me because he did not know how to adjust the hydraulic lifters on a chev 350. It cranked up there was some engine ba noise but not bad, I loaded the blazer on a flatbed trailer took it home. I drove around in the snow for about 15 minutes befor emy old retread tires decided they wernt gona push the truck anymore so i parked it. I came back a week later after snow melted and heard the most god awful knocking from the engine bay, this has nothing on stuck lifters. I removed the valve covers and 4 of the 8 pushrods were spinning freely on the drivers side engine, the number 1 cylinder was loose as heck, you could move the rocker arms ALL OVER THE valve stem. I tightened the rocker arm down till pushrod became hard to spin but the noise is still here,

Is this a classic example of improper valve adjustment or could i be looking further down into the crank piston area?

[cableguy0]

Bad adjustment can make all sorts of noise. The thing I would be worried about is the cam not being broke in properly. Is this a stock cam? What kind of oil was used? You now need to check and make sure you didnt wipe the cam out. On a fresh rebuild its hard to say what it could be the only way to really find out is gonna be to tear it down and look.

[ryanbenn1207]

white lithium was used on the cam and lifters, the truck was ran about 1200 rpms for bout 30 min to 40 min with some fluctuation to the rpm but never real high. the cam is not stock I dont have numbers but its basicly a RV cam with a lil more torque too it.

[cableguy0]

You need to use moly lube on the cam and lifters. The engine needs to be run 2k rpm or above for 20 minutes. High rpm doesnt hurt fresh cams its low rpms. Did you use a zinc additive? My bet would be your cam is wiped out.

[ryanbenn1207]

Just plain white lithium grease, problem is im 19, so my mechanic was walking me through this project, well he chewed me out saying i dont ned any lubrication and i didnt need to break the cam in. i talked him into lubing the cam with the grease told him it wont hurt and i paid 10 bucks for it lol. well then I loaded it home and broke the cam in like it was suppose to be. What scared me is when my mechanic never saw adjustable hydraulic lifters before, that shouldve been my first sign not to go any further, hes been a mechanic for 30 years im surprised he didnt know how.

[cableguy0]

Uhh yea. adjustable hydraulic lifters have been around for 60 years or more. But the valvetrain on a sbc chevy was relatively unchanged from the very first engine in the 50's up till the switch to the ls series. I hate to be the bearer of bad news but the first 20 minutes in the life of a cam is the most critical. You probably need a new cam and lifters at a minimum. Break in is crucial. The new oils do not contain enough zinc aside from very few. You should always use a zinc additive on break in. Oil should be changed after break-in. Theres a ton of reading you can do about the stuff in talking about. Go to the engine and drivetrain section and read the stickies. All the cam companies have warnings and instructions on there websites about cam break in and valve adjustment.

[ryanbenn1207]

yea the cam had no instructions with it but hey whatever ill prolly pull the cam and see if the lobes have any wear on them and the lifters if not ill lube them with some i think its "green oil" its high zinc additive for breakin in engines.

[James McClure]

Ryan. Chances are better than even the cam is toast or will be pretty in short order. I am sorry to say. Get another one and a set of lifters. Take the old stuff and give it to the "mechanic" with instructions where to store it out of the sunlight. He is NO mechanic. I worked for 33 years as an ASE certified master tech and most of those years were for GM. OK, nuff said.
Cams MUST be broken in AND they MUST be coated with a molly lube during assembly and lifters MUST soak in oil for at least a few hours before you drop them in (wipe the bottom of the lifters clean and dip them into the molly lube just before installation)
Check all your push rods for straight by rolling them on a flat surface like a piece of glass. Next check all the valve spring retainers and springs. Any thing bent, broken or missing has to be fixed NOW. Next, check all the rocker arms and pivots, any with deep scratches\grooves get trashed. Last, check stud height with a straight edge 1/16" + or- is max.
Lastly, there is a procedure in the GM shop manuals for static valve adjustment they use in the factory when they build these engines that works like a charm if you do it right. Now listen up and I'll run you thru it (print this out)
Timeing marks lined up is either #1 or #6 TDC. Cam\crankshaft timeing marks lined up is #6 TDC. Do this with the timing cover off and turn eng until timeing marks are PERFECTLY aligned. If you have to, slide the cover on and put the damper on just enough to engage the key in the crank and make sure the timing marks align. Here you can look at the distributor and make sure it's at #6 fireing position. I've droped them in wrong more than once.
OK, now your ready for the adjustment procedure to begin. With the eng in #6 you will be adjusting the following valves EXHAUST ON CYL'S 2,5,6,7 and INTAKE ON CYL'S 3,4,6,8.
NOW, TURN THE CRANKSHAFT ONE FULL REVOLUTION (360 DEGREES), ALIGN TIMING MARKS and adjust all the valves not adjusted before. That would be as follows if you want the numbers.
EXHAUST ON CYL'S 1,3,4,8 and INTAKE ON CYL'S 1,2,5,7.
Do this first. Tighten all the valves down until there are 1 or 2 threads showing above the adjustment nut. Everything will be loose, thats OK. As you adjust EACH valve, spin the push rod with your fingers. At some point it will stop. Back the adjustment just a pinch until it spins again and tighten in small incriments until it stops again. Once it stops, tighten adjustment nut 3/4 of a turn more. At this point the valve is adjusted properly, go on to the next one in sequence. The part # for the "mollycoat" Camshaft & lifter prelube is 1052365 and is available at your local Chevy store.
RUN IN. Operate engine at 2000 RPM for half hour in neutral. Throttle down and take it for a ride and drive normally for another 1/2 hr or so. Bring it back in and change the oil and filter and add 1 can of GM engine oil supliment part # 1052367 also available from Chevy. For oil I use Mobile 1 15W50 and the large oil filter from NAPA #1794 (2 quart).
Hope this helps, it was a lot of typing and running around the garage looking for part numbers. Good luck, Jim
The life of a cam and lifter set is determined by the first hour of operation

[ryanbenn1207]

Thankyou James, im going to get started on this soon as possible. I guess good news is this isnt going to be too hard to redo the first time was a PITA The engine had sat for 20 years everything that could be wrong was lol Man i dont want to redo this but i need too thankyou everyone

[cableguy0]

Not to pick apart your post because i agree with most of it except most cam manufacturers at this point instruct AGAINST soaking lifters in oil.The valve adjustment posted works just fine on stock cams but you will never get the valves set properly on a higher lift performance cam. You need to ensure each lifter is on the heel of the cam lobe to get proper adjustment. i prefer to set them one cylinder at a time. That method goes as follows. Pick a cylinder and spin the engine until the exhaust valve on that cylinder starts to open and adjust the intake valve. Now when the intake valve is almost all the way closed adjust the exhaust. run through the firing order in the engine and you will be done. this article explains the process in more detail and gives some other good tips. http://cranecams.com/?show=techarticle&id=2

[ryanbenn1207]

It may be a long time till i get my blazer running i dropped about 400 dollars on this, was my birthday pres too myself lol. I learned a lesson when a friend tells me he dosnt know how your valves and lifters work, well...."STOP RIGHT THERE" it makes sense that all my pushrods and lifter are loose now, after the cam wore out there wasnt any more tension on the lifters anymore, but hey ill get this darn truck running again. I have a 4 bolt main 350 block I can use but needs machining, would it just be better to rebuild a complete engine? I know someone who has extensive background on 350 engines who will walk me through rebuilding. I dont know what condition my pistons and crank are in the current engine, I know the timing chain was so warn out you could almost make it skip a tooth by hand. this tells me high mileage.

[leegrady]

Lot of really good knowledge being past on here. Cableguy0, and James Mcclure really now there stuff, (I can tell the real mechanics from the...).

Don't most new cam and lifters come with break-in lube? Mine always did. Instructions too.

I always get around to adjusting my valves after break-in while the engines is running using an old pair of valve covers with the tops cut open.

To get my edge, I see you in rear view mirror, whenever I do research to install the cam that works, (the formula) and not create a second prize, not just bolt on performance, but really increasing brake mean effective pressure, (bmep). I always, always, always...dial in my cams. Esp. high performance engines.

[ryanbenn1207]

Well i went out removed the fan and shroud and messed around watching the rocker arms, I got to the number 1 piston exhaust stroke and adjusted the intake valve to zero lash and 3/8 of a turn down is this correct? I would like to properly adjust my valves before i start pulling a camshaft again, keep in mind i have no garage so pulling engine is not a option. I also like the adjsut one cylinder at a time, Its simple for me.

[ryanbenn1207]

I just had too add this lol, ive researched chevrolet timing and camshaft break in it took days to get half of what the good guys here have shared with me, im in debt maybe one day ill know my stuff and be able to return the favor, thank you everyone

[leegrady]

Cam and lifters are always changed together. When ever you change the camshaft you change the lifters. No sense making a valve adjustment until you install the new cam and lifters.

When you ran the cam that's in the engine now did you change the oil and filter after running the break-in procedure? The reason I ask is that valve trains don't knock, they tick. Is that knock coming from somewhere down low. Like is it coming from the oil pan?

[ryanbenn1207]

heres what i did

1. removed carb, radiator all hoses, transmission cooler.
2. drain oil removed filter
3. remove intake manifold
4. removed lifters 3 were stuck so bad took brake cleaner channelocks and vice grips, the lifter wall may be scratched
5. removed water pump, balancer, timing cover and gears.
6. pulled camshaft one lobe was gone others warn badly but camshaft bearings appeared to be fine, did not replace cam bearings.
7. installed new camshaft with generous amounts of white lithium grease.
8. installed new timing gear and chain
9. intsalled new lifters with litium grease
10. installed intake manifold
11. installed dizzy and radiator and cooler and all other hoses
12. refill all fluids new oil new filter
13. timed the dizzy
14. it cranked idled nicely would stall bad after 1700 rpms, it neve rliked going above 3000 rpms at all would stall bad no power and sputter, also i noticed blue smoke that would never go away no matter what i did to carb, then parked for 2 weeks and thats where i am at now

[ryanbenn1207]

update everyone, i adjsuted the valves and for the first time ever the truck stayed running, and started very easly i always thought i just didnt know how to drive a carburetor but no the truck started right up, i still have a very loud knocking going on and it sound like camshaft area im afraid my camshaft may be dry.................... but the lift in every valve is nice i think my cam may not be damaged if im lucky. Does anyone have a trick for lubricating a camshaft, that is dry without pulling it?

[faribran]

do you have oil pumping out of all the pushrods/rockers?

[jake wells]

when you are installing a new cam in a engine use ZDDP assembly lube and replace the cam shaft bearings. don't skimp either when it comes to rebuilding something never reuse used worn parts replace what you can. is your noise coming from the back of the engine? do you have a mechanics stethoscope? exhaust manifold gaskets and badly adjusted can make it sound like its "Knocking"

jake

[Camaro_nut2001]

I'm not going to add my two cents as a couple of members have already posted it but I would like to know what brand cam did you use and where did you get it? Did you buy it from one of your mechanic friends that told you it was new but the box had been opened or something to that effect? I am a disabled Forklift mechanic of about 17 years but I have played with Hot Rods since I was to young to remember as my Dad used to run dirt track every Fri. & Sat. night. He taught me more than any of the schools or certification classes I had to go to ever taught me. All he ran was Chevrolet and that's all I play with. The reason I ask is I have put ALOT of cams in and NEVER bought a new one with no paper work. How did you set your cam up? Are you running it advanced or retarded or straight up on zero or what? Without a cam card how did your mechanic know how to set it up to perform the best with your engine specs? I'm kinda confused on this one.

[ryanbenn1207]

Well to be honest i forgot to check for oil, when i parked it i thought it had oil coming out. ...................well.............................. THERE ISNT ONE DANG DROP OF OIL COMING OUT OF ANY AND I MEAN ANY OF THE PUSHRODS. looks like i found me problem huh

[ryanbenn1207]

and im a 1/2 quart low of oil forgot to add that

[ryanbenn1207]

the cam is a elgins, we timed it at straight up 0 no advancing, the cam was brand new parts guy delivered it too me, the mechanic and i worked on this together, but he adjusted the valves when i wasnt there and obviously they were wrong the engine sounds a 1000 times better at idle besides the knocking. now i need to find out what caused my oil too stop pumping......

[cableguy0]

OK more info leads to better answers. If the lifters were that stuck in the bores. That means theres A) a ton of buildup in the engine B) the engine is rusty inside from sitting so long C) the lifters were mushroomed out on the bottom from getting beat to death by the cam Or D)all of the above. If the timing chain was that worn out and the lifters stuck in the block. That engine needs to be torn down completely and rebuilt or you need to find another one. Theres going to be oil flow issues to go along with the problems you mentioned. The top end is the last thing to get oil. Oil in a sbc run from the pump up to the #1 main then up to the cam back to the distributor where the distributor actually completes the oil passage for oil to continue down the other side. after oil runs through the lifters it goes up the pushrods. Lowest pressure will be at the pushrods always no matter what. With that said there should still be enough pressure to at least make a big mess in the engine bay. the cam itself is splash oiled by the crank. Thats the reason using the proper lube during installation is sooo important. Its hard to describe noises through text on a page. But if you have a knock and not a tick or rattle. Like i said words are hard to pinpoint a noise. You likely have some other issues and a rebuild is in order. to be honest the 400 bucks you spent would have bought you a rebuild kit with new pistons and a cam and you would have been part way there on the rebuild already. You would then need machine work and the heads rebuilt but it would have been money better spent. Is this sound like a hammer in a tin can? or is a fast ticking sound? can you feel the knock?

[ryanbenn1207]

sounds like sledge hammer in a body shop and it vibrates the vehicle