Valve lash adjustments

[Peter Malcolm Jardine]

Okay.. so I have this 283f Chris Craft engine more or less back together now... crank, pistons, cam, heads, lifters, pushrods, rockers.
However, the valve lash adjustment has to be done, and I can't remember how to establish the abitrary cold position before starting the engine up... anybody out there remember? I know it has to be done running... down until the engine stumbles then back usually 3/4 of a turn, but I should do a relative setup before starting.

[ 12-12-2002, 07:10 PM: Message edited by: Peter Malcolm ]

[imported_Conrad]

With the piston for the cyl. being adjusted at TDC, tighten until you can just spin the lifter with your finger. The rocker arm should be on the surface, but not tight.

[Peter Malcolm Jardine]

Thanks Conrad.... I knew there was a twick to it.. :D

[Peter Malcolm Jardine]

spin the pushrod ... right?

[Gary Bergman]

yeah, all good engines run gud on a 'tight'spin..leaves just enough to seat right when running.

[Peter Malcolm Jardine]

Believe it or not... besides aluminum head 350's the last engine I did was a 239 ford... looooong time ago.. thanks guys :D

[imported_Conrad]

Yup- push rod. Its been a while, senility setting in, all of that... :D

[Peter Malcolm Jardine]

better than forgetting it all together :confused: :eek:

[capt jake]

283?? Make sure you prime the lifters! You don't want to adjust them too tight. If they are not primed, you run the risk of creating a negatve lash (open valve).

I have always adusted small block Chevy's while running. You need a set of old rocker covers, cut out the centers to allow access to the adjusting bolts. Fire it up and adjust until there is no lash. Assuming, of course, you are using hydralic lifters! smile.gif soids take another course of action. smile.gif

Chevy's! :D :D

Oh and be ready to get an oil bath, even with the covers.

[John B]

239! what? a flathead. I've still got one but I've forgotten all that stuff.

Now however I will announce 18436572. Chevvy firing order. might be handy .Since participating in this forum I've been able to share that arcane bit of knowledgeat least 3 or 4 times. Joy.
PS I had a solid lifter 427 in a 59 pontiac and I had to set those suckers all the time. OOOOO yeah. skinned knuckles, burnt elbows, hot oil smoking.

those were the days. LOL.

[SailBoatDude]

Drop your lifters in a jar of motor oil over night before you install them. An old trick (like me) keeps you from setting near zero lash on leaked down lifters (bad thing).

Personally I've never bothered with a preset of any kind, just ran the nut down till it made contact, and did the lash after the start up. Sloppy lash will not hurt the motor if you do the lash right away.

They also sell these little oil control clips that snap over the pushrod end of the rocker to keep the oil from flying all over the engine compartment, they don't cost much and you'll like them if you've done lash without them before. You can find them on the red "HELP" cards in your local auto parts store, though the top cut off an old set of valve covers works okay, but some oil still gets on you and the compartment. If this is a high revving (over 5000 RPM) high lift (near or over .5") cam in this 283 (it's a very willing motor in this regard) you may want the cheap insurance of "Poly Locks" (at least that what we called them) instead of rocker nuts. They are an elongated rocker nut of better metal and have a set screw in the end to prevent them from backing off in high rev/lift setups.

Good Luck.

[capt jake]

No offense Sail Boat Dude, those clips are worthless!! I mean wortheless! Get an old set of covers and cut out the centers. This comes from personal experience! Ever tried adjusting valves with a High volume pump with clips?? You are talking clips a flyin' and and major oil bath (in about 20' each side)!! smile.gif

Now soak them over night is good!! Give them a prod with a push rod! I mean a real good prod!! Poke them as much as you can to help prime them little buggars! Poke, poke poke!!!

Clips are worthless, get a set of old covers and follow the 'old' codgers advice!! smile.gif Keep the covers, 'cause you will need them again!!
Chevy's spit oil like there is no end (out of the lifters of course!) Not like Detroits or FORDS!! ;) ;)

They say Detroits were designed to oil the roads to keep the dust down! That comes from an old Cummins friend!! ;) Not me! ;)

[capt jake]

OK I have tried explaining this process 3 times, bu I am told that I have TOO many images to post!

Scruze me, i was only editing and adding to a prevfious post!

OK, I am better, let's try this again.

When you are done with setting the cam ( the break in) and you are back at an idle.

Adjust each lifter down until you hear nad/or feel no clatter. Then back it off 1/4 turn!! Done!! smile.gif

When you are all done with all 16, you can crack a beer!!! smile.gif ;)

Mind you, this was supposed to be included in the previos post, but I was not 'allowed'! ;)

[Peter Malcolm Jardine]

already primed the lifters, and just set them tonight... yeah the old cut out covers is good..

and nope this is 12756348.. counter rotation, even the seals have to be

Now boys boys... this is a stock 185 horse chris engine..nuffin fancy. I had to get it bored 30 over new pistons, rings, bearings, seals, gaskets, starter, fuel and oil pump, lifters, guides,seats, valves...etc. its fresh, and right, last time I will do this motor in my lifetime

[ 12-12-2002, 11:53 PM: Message edited by: Peter Malcolm ]

[capt jake]

Peter, the cut out covers aren't 'good', They are a MUST!! They are the only way to fly! Been there, done that! smile.gif

[Peter Malcolm Jardine]

Oh and I built a decent engine bed so it can be run before its installed :D

[capt jake]

All the better to keep the oil of of you!!

Right on Peter!! smile.gif

[Peter Malcolm Jardine]

I don't like no leaky enguns ya understand... I learned what I know mostly from this old marine mechanic I bought a bought from 20 years ago... he was very fussy. A great mechanic. I will post you pictures when i get the rest of it together. Its puuuurrrrty. The machine shop that did the block and crank and heads did a great job. This old motor didn't even have hardened seats.. it was tired. I kept all of the old parts that worked, but I figure most of the work is takin it out and putting in... :rolleyes: :D

[capt jake]

If you are talking about the cut out valve covers.. Look at the incline of the heads! They lean outwards, right? Those measly clips deflect the spray, but thy do no contain and redivert the oil! With no 'cover' in place the oil will run off onto the exaust manifoild and thus, create a HUGE smoke field ( or fire).

Those clips (I have tried them) are worthless is the largest sense!!

Trust me!! Been there, done that !! The oil, not contained, will run off onto the exhaust manifold; big mess! Big smoky fire ridden mess!

Buy some old covers and cut them out!! You will thank me later!!! Really!!

[Ken Liden]

From the professional point of view! First determine if your lifters are indeed hydraulic or solid lifter. Most Chris F series were solid lifter. There were several camshafts all with different lash requirements. However let's proceed as if you have a hydraulic cam and lifters. You must run hyd. lifters on a hyd cam and solids on a solid cam. Do not mix parts.

If you are going to try to re-use old parts the lifters must go back into the same lifter bores from which they were removed and you must not use lifters from one cam and run them on another or vise versa. The cam lobe must be free of any etching even in the area opposite of the nose. The old lifter bottoms must be no less than flat and preferrably will be slightly rounded. Not concave!. If the lifter is concave throw them and the camshaft away. It's junk.

Now we can install the cam. I assume that a professional has put in new cam bearings or at the very least the old ones are in good condition. Coat the cam lobes with camshaft break in lubricant. Put assembly lube on the cam journals and cam bearings. Slide the camshaft into the block and try not to nick the bearings. Sometimes it is helpful the bolt the cam gear on so that you have a handle. Install timing chain taking care that the timing marks on the sprockets are aligned. Coat the lifter bottoms with cam lube and the bodies with assembly lube. Don't waste your time dropping the lifters into a can of oil first to fill the lifter. It's just a myth. The hole in the side of the lifter is so small that the surface tension of the oil will not allow it to flow thru the hole. It takes about 8 lbs. of oil pressure to pump up a lifter. Before you drop in the lifters make sure that you can depress the center plunger about 2/10's of an inch. ( that varies with brands) You will feel spring tension which will return the plunger to the top. If the plungers do not compress you should bleed them before you put them in. You can bleed them by holding them in a vise with a short bolt in the push rod socket, close the vise slowing but firmly and you will see a few drops of oil come out of the small hole in the side. Do not clamp on the side of the lifter. Compress only from the bottom.

Drop in the lifters, lube up the rocker sockets and fulcrums, and both ends of the pushrods. If you have timed the cam properly you can run the rocker nuts down until you see about 1/8" of stud sticking thru the nut. Now you can start adjusting. I preferr to adjust the valves before I put on the intake manifold. That way you can see the lifter position which is a great aid. Starting with the first valve rotate the engine until the lifter travel bottoms out. Then adjust the rocker until there is no vertical travel in the push rod BUT no load on the plunger. This is the zero lash position. Then simply turn the adjuster an additional 3/4 turn. I just go down the line in turn so that I don't get lost.

Lifers adjusted in this manner will never have to re-adjusted in the normal life of the engine.

Last but not least. Start the engine, take a quick look around for any condition that you can't live with for 30 minutes. If all is OK run the engine up to about 1400 rpm and leave it there for at least 25 minutes. It is critical that you do not slow operate the engine during this period. This procedure is to burnish or mate the lifters to the cam lobe. The bottom of the lifter receives no direct lubrication and relies on crankcase mist caused by windage from the crankshaft. As the engine operates the lifters will eventaully grow quite as the air bleeds out of them. Don't be surprised if one or two take 20 minutes or more. Good luck.

[Peter Malcolm Jardine]

Thanks Ken... This block had one cylinder worked on and the taper was out too far to use existing pistons, so I had the block bored, new pistons, new bearings, the cam was good, new lifters, and had the lifter valleys cleaned up, put new hardened seats in the heads, new valves and guides, new fuel pump, oil pump, had the starter freshened, cleaned out the alternator and put new brushes in.The crank actually polished up very well so I didn't have it turned.This is a hydraulic lifter engine RH rotation, so it has the gear driven timing too. I even remembered to get the counter rotating seals :D I left the lifters in oil just because it gets them nice and oily, but I know the surface tension thing...The rest of what you told me is great advice... I knew the cam break in, but you have explained it better to me as to why. I always heard it was to break in the cam bearings. Thanks again

[SailBoatDude]

I don't sugest steady RPM for any type of valve train "burnishing" nor does GM. The recomended technique is to vary the RPM so that you get an even pattern on the lifter face in this case. Constant RPM during this part of the break in could cause a flat spot on the lifter face. We always ran the RPM all over the place to prevent this from happening and so did everyone else. Maybe GM was just being safe, but . . .

I've used the flapper style of oil control clips several times with few problems, though I did use the roller style once and launched two or three several feet. If the heads are clean and the oil warm, it drains all right, with some leakage, but not the cloud of smoke described.

In fact GM doesn't recommend steady RPM for any of the break in time, giving parts a wide range of wear pattern to work with. Its quite correct that you not operate the engine at prolonged low RPM, but not steady anything in the same regard.

[Ken Liden]

Sailboatdude, I think you missed something in the translation.

It is true that when breaking in the engine you should vary your operating speeds. The reason being is that the crankshaft sets up windage in the crankcase causing an air flow pattern. That pattern or flow circut changes with different speeds and carrying with it oil in suspension in mist form. As the crank spins thru the mist the oil tends to form a rope much like a tornado funnel which causes not only a drag on the crank but can actually deprive certain areas of mist oil. Mist oil is vital to those componets that do not receive direct lubrication such as the cam lobes and lifter bottoms. Remember, lifter oiling is from the side and its sole purpose is to fill the lifter body and on some engines to provide a pushrod oiling system for the rockers. Some factory solid lifter engines such as the 427 Ford hi performance and marine do not even have an oil galleys to the lifters. They are entirely mist oiling.

Cylinder oiling for the most part in these engines is the result of oil being thrown from the rod journal after it has exited the rod bearing.

Camshaft break in is not the same as engine break in. Like I said earlier the cam lobe and lifter bottom in all flat tappet engines of the OHV design depend on crankcase mist for lubricatin of the lobes and lifter bottoms. Even wear of the lobe and lifter is a function of design, not varied speeds. Lay a straight edge across the bottom of a new lifter. You will find that it is crowned or high in the middle by as much as .002". Most people don't realize that most(but not all) flat tappet camshafts are ground with a taper. That is to say one edge of the lobe is slightly higher than the other. Usually .0005"-.001". In operation the lifter spherical face is presented to the tapered face of the lobe. In essence you have two spherical faces making contact. The third part of this design is that the lifter bores in the block are not aligned with the cam lobe but are offset which in the end causes the lifters to rotate resulting in even wear. And they rotate regardless of rpm for they can do nothing else.

Sorry for these long winded replies but after 38 years as an engine rebuilder I have yet to have a new cam go flat.

[Peter Malcolm Jardine]

Once again Ken, thanks for that explanation. I have received most of my motor education in situations that somewhat reek of hocus-pocus.The mechanics I worked with were good, but not as long of theory as I would have liked. While I knew that camshaft break in was a must.. Now I have the as Paul Martin would say the REST of the story....One additional question... comment for me on early oil changes on an engine of this vintage. Earl Phillips, my late marine mechanic friend, was of the fanatic 4 changes in the first 20 hours or so. He maintained it was the cheapest insurance ever. Anyway, I have wondered about synthetic oil as well, which I have rarely used, but think it might "store" better given that this motor might receive 150 hours a season.