Hot Rods Valves romancing pistons, problem solved

Plus you can make a grilled cheese when your done. Lippy

 

Ask your neighbor, friend, expert to lend you a hand. I don't understand why you need our opinions I guess, Lippy

 

It's pretty simple you need valve to piston clearance for that cam and how it is installed. IMO (which for what it's worth, you can gain said clearance one of several ways. Thicker head gaskets, notch the pistons, (I would not even consider sinking the valves),change the cam, change the pistons, or rebuild the whole deal and check and recheck everything correctly. Sorry if my answer was not what you wanted to hear. I'm really a nice guy.

 

Have the heads ever been milled, and if so how much?

 

I contacted the manufacture regarding how much I could "eyebrow" and here is the response I received. Thank you for the inquiry. I cannot tell you how much can be removed but if you take the pistons to a competent machine shop they will have a fixture to measure head thickness. As long as you maintain .250" head thickness anywhere on the top of the piston you can remove as much as you need. I hope this helps. I fabricated a cutter last night using HSS (High speed steel) and made a trial cut, cutting just a little into the eyebrow, I think I got the diameter about right but believe I may have to modify the profile to round the edge a little so as to not create a stress riser with the cut, any suggestions? I don't know how the cutter works when it contacts the face of the piston, since I didn't go that deep.

 

looks good
check out this one
http://ls1tech.com/forums/generation-iii-internal-engine/832105-flycutting-tools-4.html#post10663794

 

You say you don't have any clearance between the intake valve and the piston, how is your cutter going to fit in there to do the cutting ?

If you rotate the crank to get the piston lower in the hole, your new pocket might be in the wrong place when the piston is a TDC

Since the valve is at an angle it all changes with crank rotation

 

I really do think it would be easier, quicker, less headache and overall better for you to just clay the thing to find out exactly what kind of clearance you do or do not have, pull the engine or pop all eight rods and pistons out and take them to a reputable machine shop and have them cut. How are you planning to get all the crap out of the cyls after cutting? JMO. Lippy

 

Bring piston to tdc and then lower cutter in valve guide to desired depth.

 

shaving cream/foam and grease is some of the things used to catch . trap
shavings whilst cutting in those areas...
one guy said he ran the vacuum to catch the metal...

 

I have been working with another fella on a blower motor ( a little extreme for the HAMB) that is a street strip motor. It has been completely assembled 7 times the last time everything was torqued and spun with oil in it. It is in pieces for final inspection now then it will be screwed together the final time (we hope ). But it is going to see some pretty serious beating and we want it to be right before we ever fire it.

That is motor building. If you build the same motor day in and day out sometimes you can just screw one together and get lucky. If all you did was screw it together and it hung and you didn't have problems you got lucky.

 

My experience has been with the piston chasing the exhaust valve as it closes. Yes the intake is opening but mine always seems tighter on the exhaust side. My first thought was perhaps the cam is advanced so that the exhaust is more closed and intake more open at TDC. But OP says no, so I guess it's just a case of wrong pistons for application. Cut to fit.

 

In my case with the Boss, this was a rod failure. The romancing was just the piston trying to exit the back door

 

Holy crap 7 times and working on eight ?!?

To assemble a motor?!

I have built everything from a lawnmower motor, 12 valve Cummings , small big Chevy ford Pontiac etc... to 3500 yes 3500 hundred horsepower TFX PSI Blown alky injected hemi ..,

Never and I repeat never have I had to assemble a motor 8 times 3 yes... 4 on a odd ball combo maybe...

 

That's sounds like ' Engine Building Class 101 ' 7 times apart ?

 

Last time I checked there was such a thing as bolt stretch.. Bearing crush ..etc..there is a whole bunch of tools that read in thousandths and do some math etc..etc... 8 times ...????

I am not going any farther .... I need to go degree a cam and fly cut some Pistons..

 

Individual pieces take time to measure and fit correctly. Blue printing is just another bullshit word to describe good practices. On my GMC's for Bonneville it takes 2 or 3 times before I'm happy with the crank in the block. Then it comes out for the seal. All the Pistons go in without rings on the first fit too. At least my valves never hit a piston, close but right. Finicky yes, but I've been leading my class since 1985 so I'm not going to change

 

if its a Howards it is quite possible its on 108 and ground 4 degrees advanced, so the intake CL will be 104 even if he installed it dot to dot, so its going to opening pretty early. I would strongly suggest claying it, and rolling it from around 30btdc to around 30 atdc. Better safe than sorry. Check the intake opening point on the cam card, and start there, I havent calculated the valve timing, just pulling 30 deg. BTDC out of my ass, but its probably pretty close to that.

 

I have raced a complete season on a BBC blown injected on alky 10 races making 1500 hp if it making a dime. Have the slips to prove it. With nothing but regular maintaince. At least 20 passes with 30 pounds of boost and 36 * in the box....,Why ?

Because I measured twice and assembled it correctly..,,8 times ... No Try once ...

 

seven times is not unusual in my books, I usually spend quite a bit of time swapping rods and pistons from throw to throw just equalising the deck heights as close as I can.

 

I commend you for that ..but from the OP he is not going to be swapping around rods ... He did not even degree the cam .,, Let alone check piston to valve clearance ...

 

This is a sideways picture of how i decide if the valves will hit the pistons or not. Soft springs so I can flutter the valve as I slowly turn the crank. I can feel if they are getting close before they get to close. With clay if your clearance is -.002 you may just run it over the top and stress stuff.

 

You might try these http://www.lindytools.com/#lipc/c1yc1

 

True...

 

I do pretty much the same thing too first. Then I usually clay it too for a visual of the tightest it's gonna see.

 

I have some pictures of my set up for degreeing the cam. It includes two 1 inch stroke indicators and adjustable push rods with a large flat end to indicate from and studs with guides to keep the pushrods straight and mount the indicators. But i can and also do mount the indicator on the retainer to give me a running check on how much clearance I have at all times. I never use clay unless I wanted to see just where it was touching first. My checking springs spent several years between two rocker arms on a 270 GMC before becoming tooling.

 

One thing to keep in mind in this case is that the valve notches are not large enough in diameter as well as being not deep enough.
It depends on how you are going to notch the pistons, with the method he is using with a valve with a cutter on the face, I would do it in two steps, First I would use the cutter to clean up the notch so the valve isnt tagging on the corner of the notch as you see in the first pic. Then I would clay it, roll it over and see how much clearance there is in the notches and see if they need to go deeper. Its hard enough to get compression with flat tops, so (and I know this is just me, everyone else sees compression as some horrible thing, to be avoided at all costs) I wouldnt want to go in and deepen the notches more than I need to.
I agree that with the conditions the way they are in the first photo, with the valve tagging the side of the notch, you could damage the valve by just going ahead and claying it, but I take it for granted that is obvious where you have a witness mark on the edge of the valve notch, like in this case.

 

OP only states "drive ability issues". What does that exactly mean ? Could it be he wound the snot out of it then the issue happened ? Anyone ask how much pre-load he set his lifter's at ? But clay in the wrong hand's wouldn't answer that question either.

 

The pushrod that bent and fell out may have had something to do with "Drive ability Issues"

 

many an over rev, -n- weak springs, have ended up like that,
piston meets valve situation