Inliners International Forums General Discussion Hi Performance Setting valve lash - need help

Hello all!
I am in desperate need of help!
I have a new engine combo this year and, it’s been fighting, to say the least!
I was having a rattle under load, which seems to have been a lifter failing.
To confirm this, I have switched to solid lifters.... and am having a nightmare of a time!
I followed the procedure in my repair manual, for setting solid lifters. Ran ok, but was ridiculously noisy (much more than I’ve ever heard solids before!). So, I reduced lash by 0.002” and tried again. Ran better, still too noisy! Again, dropped 0.002” and it’s much quieter... but would seem I’ve got an irregular miss!
Is anyone running solid lifters? What is your lash set at?
I’d very much like to get rid of the roller lifters and just run hydraulic with stamped rockers... but, when I installed the stock ones, they were hitting the studs near full lift... need a pushrod length change in order to use them.

You didn't put those on a HDY cam did you? You have a roller cam??

What type of cam do you have.??

It’s a comp hydraulic cam... my builder said it will be fine but we will need to figure out the lash.

That’s a bit of a head scratcher for me. Hydraulic grinds tend to be pretty aggressive in clearance-ramp area because the hydraulic action of the lifter acts as a shock absorber. Not sure if this is adding to the chatter when the lash is taken up.

I am running solid lifters on my stovebolt. The cam-card calls for .008 clearance on the intake and .013 on the exhaust. When I first put the engine together I lashed generously at .010 and .015 so that I could sort out the rest of tuning before addressing the racket.

Once I had the engine running and idling smoothly I began to take out lash in order to reduce the chatter. Once the engine was hot I dialed the lash back to cam card specifications. It was still quite the chatter box. Over time I have tightened the intake lash to .006 and the exhaust lash to .011. It is considerably quieter at idle. The lash spec is there to prevent heat soaking (and resulting metal expansion) from holding valves open when they should be on their seats

get rid of the roller lifters?

I never had roller lifters... roller rockers, yes.

So, I tore it apart last night. Wanted to put it back to where it worked before I started dialing up the power. Very first lifter to come out was stuck.... destroyed by the cam. Ended up with 3 lifters destroyed. Stuck the camera down the lifter bore and the ok a look... the lobes look ok! Ran my finger over the lobes and they feel ok, too.
I installed the original hydraulic lifters and set pre-load as per the manual.
Today, I will change the oil and filter. Use break-in oil and run the break-in procedure. Change the oil/filter again and roll the dice!
I’m neither that lucky nor that good... but really, what’s the difference... if the cam is done, the engine has to come out anyway. At that point it will be a full tear down and clean.

You never mix. Roller for roller HDY for HDY Solid for Solid. That is why they are designed to go together, you got lucky that it did not mess up the cam. Keep us posted on how things turn out.

Well, I did the break in this afternoon... everything seems really good. Very responsive. There is still more noise in the rockers than I am use to (or like)... but I found out that my rocker cover only clears the nuts by about 1/4”. With 3 gaskets on. So, that tight proximity to the huge hollow ally cover will definitely make the noise louder!
So, I will be buying the spacer. But, that will take 3 weeks or so to get to me... so I will be looking for an alternative in the meantime.
Tomorrow, I will change the oil and take it for a drive.

How thick of one do you need or want?

Didn’t drive it... noticed some of the adjuster nuts are actually touching the valve cover.

I need 1/2”, Larry.

That could make some noise.

Guess it doesn’t matter anymore.... tennis ball sized hole in the block. Broke #2 rod and pushed it out.

Could that have been the noise all along? That is too bad.

Loose rod cap and it let go or bad wrist pin ? Dang That really Sux

Broke the rod. The big end was still in place. One of the nuts was ripped off... but even the bearing hadn’t spun. Once I freed the twisted rod from the counterweight, it spun as normal.
Wondering if it was the RPM that caused it... 6200
My AF meter is on the fritz... reads sometimes. It’s been ongoing all year. On my third O2 sensor this year. So, I’ll replace the meter with an AEM unit.
Maybe it was a combination of being lean and the high revs?

Anyway, what’s done is done. So, not I need to decide whether I build another 250, use an Atlas, take up the offer of a BMW M50, or look towards a Barra or 2JZ.

The JZ is probably the smallest package and the easiest to build to 500+: stock head, block, cams, crank, water, oil.
Will the Barra or Atlas fit in your bay?

Not sure, tbh. It’ll be tight!!
The 250 was tight enough!

I never measured mine, but the JZ bore pitch is tiny at 3.622" (compared to 4.400" for the 250, 4.055" Atlas) which shrinks the overall length. The Barra may have inherited 4.080" pitch from the much older pushrod 144, 170, 200, 250.
The front drive and bellhousing lengths...??
Not much weight saving, only the JZ head is aluminum.
The JZ deck is only 8.543" (250 is 9.150", Atlas is 9.160", Barra 9.228") but the excellent factory JZ oil pan is pretty deep.

The M50B25 (offered to me, running engine with harness and computer) measures 28” long

Economically speaking, the 250 build is the best way for me, at the moment.
I am looking at the following
Forged Ross pistons
Turbo cam
My top end
Studs top and bottom
1/2” off the crank counterweights and balanced (recommended by an engineer)
Sniper 650 power adder

Sound reasonable?!?
The sniper is extra... I’m not paying for it.

I'm still trying to track down what constitutes balancing an L6 engine, which is frequently referred to as "naturally in perfect balance" (not completely true, there is always some rocking couple).
Any details? How is the counterweight mass determined?

I think that naturally balanced is somewhat of a misnomer. I think that because of the layout of the I6 crank the balancing of the crankshaft is independent of the mass of the big end of the rods:


In this post over on Supra Forums ‘turbotoy’ describes the concept of static balancing. The idea that a crankshaft placed on ‘frictionless’ bearings would not move no matter how it was laid to rest. With the weight of the throws perfectly offset by the counter weights the crank shaft should not ‘settle’ into a heavy spot.

But he still argues for dynamic balancing with all rotating components attached. If the bolted on bits all weigh the same then why?

Inline engines are not balanced with Bob weights added to the rod journals like a V engine is. If he argues that they should be, he is simply wrong in his analogy and does not understand the difference between the balancing of a V engine versus an inline.
The rods, pistons, wrist pins , rings and bearings are balanced separately, and their mass cancels or offsets the others. On a four cylinder, you have the components 90 degrees apart to do this like a seesaw. On a 6 cylinder, it takes a set of 3 of these components to offset and create balancing. Similar to a ceiling fan with an odd number of blades.
If you remove counterweights or knife edge them, like we did all our race crankshafts. Then you will have to rebalance the crankshaft to correct the state of neutral balance because you will have spots where more metal was removed than in other spots to maintain the factory balance. We also welded up the factory drilled balance holes in the counterweights to remove unwanted windage issues that they create.

With the weight of the throws perfectly offset by the counter weights the crank shaft should not ‘settle’ into a heavy spot.

But... the rod big ends are rotating weight, what opposes them?

Counterweight opposes counterweight and rod journal opposes rod journal. Something that has never been mentioned before is also the front half of the crank is also balanced to oppose the rear half of the crank. A static balancer is ineffective in telling you if that is occurring or not occurring. We had a Sterwart Warner balancing machine that is so sensitive it can tell you to within a few grams if the crank is balanced. On a static balancer, you can still be more than 30 grams out of balance and the crank wont spin or rotate to indicate it's still out. Fine for a shade tree fix, but the out of balance the crank can still have is not really balanced if you are having to pay for it.

So the bare crank will never stop in the same place twice, and the other bits should just be made equal?

Yes sir! You are correct if you are using the static balance method. Just to be clear, there is nothing wrong with that method, but it does have limitations compared to a computer balancer that can sense imbalance front to back. Which is just as important and can still cause an engine to vibrate or shimmy if it isn't corrected. Just like it isn't balanced at all. Great for tires and wheels and other things that have a single plane of rotation like flywheels/flexplate and harmonic balancers and even propellers, but not so much crankshafts with multiple planes in them.