Technical Flathead valve to head clearance?

Random thoughts, not sure how they'll fit in with all the different things cooking.
Ol Ron has posted a quick way to fabricate a FH doming cutter tool if you need anything in that area.
Don't cut decks...as with all production engines, you don't want to lose any thickness there both for stiffness reasons and for thread depth reasons.
Get heads fitted to pistons as well as possible...total happiness is probably unlikely here, but try to match curves as much as possible so you get decent quenchiness over as great an area as possible rather than 2 different curves achieving correct clearance in a tiny area.
Worry about valves after you have done the best possible at the piston.

 

Yeah I measured the valve angles side to side and gave those too him when I dropped off the heads. I messed around with a set of iron heads tonight and when I clayed them they just kissed the valves as well... So I am thinking the the higher lift cam in conjunction with the new valves that look a tad thicker than stock and new valve seats just puts them up too high at the fillet of the back of the chamber Unfortunatly. So I just gotta wait and see how it all works out.

He said he should have time to do the heads Friday so hopefully I can finally get it together and hear it run!!!!

 

Sounds like you have a plan - this will all work out. At least you're smart enough to check this stuff - plenty of guys didn't . . . and paid the price!

 

Well I got it together and ran it about 70 miles.... Then because I am a little nuts I pulled a head just to be 100 per cent sure of no contact......and success!!!

So I just got done buttoning it back up again and running it up to operating temp... Tommrow I will fine tune everything.

Runs really well!!!!!

 

Looks great and very glad to hear that things appear to be running well. Did you take any pictures of the chambers when they were complete? What clearances did you end up with?

 

Today I got another 100 miles on it... And it was running great untill it wasn't....... Aparently 0.030 wasn't enough once I retorqued the heads and had bit nice and warm reving it out a bit more.....

 

Well, it appears to me that the fly cut that was done - didn't go all the way to the edge of the valves - you can see that on both sides. So in truth, the fly cut did nothing for you. Did you clay everything once you got it back? It had to be hitting or darn close on the outer edge of the valves. It needs the deepest cut to be right in the radius/corner where the back wall meets the top of the chamber.

 

Also, what are the installed heights of the springs and which springs did you run? Do you know the lbs of spring pressure on the seat? What RPM were you at?

 

It didn't hit the edge of the chamber on,the radius it hit the face of the valve,... The other one hitbthebedge because it was bent when it hit the head of the other valve.

I honestly don't rember what it coated at.... And oddly it was fine last night when I pulled it to check.... But. Who knows.

I don't know on the spring pressures.

 

It was about 4500 rpms.

 

Didn't say it did, but it hit the head on the outside of the flycut. The flycut was not done correctly. I'll mark-up the picture when I get home.

 

You need to know what springs, what installed height and what lbs on the seat. Who assembled the motor?

 

A local machine shop.

 

Ask them what springs, installed height and lbs of pressure on the seat. What type of lifters do you have? Solid or hollow - and whose?

 

Reds headers hollow is what I bought.

The springs were stock replacements

 

Yo Gang - just got back home from having too many wings for dinner . . . and maybe too many beers . . . so here yah go:

Take a look at the picture below - then we can chat about it:



1) Red Line: That shows approximately where the fly cut operation was done
2) Green Line: Shows about where I believe the outside of the valve actually hit the head. Notice that this areas has NOT been fly cut - so the outside edge of the valve - hit this part of the head.
3) Blue Line: this is approximately where the fly cut operation should have cut - notice that the diameter is much bigger than the valve size - it matches the basic radius of the valve pocket in the head.

With all that said, the situation STILL may have required hand blending in the corners of the valve pockets in the head - to ensure that the outside of the valve had clearance. I usually have to do this by hand - unless I have a CNC machine doing the work with a 1/4" ball mill (such that it can reach the corners of the valve pockets).

Lastly: Seems that the engine ran fine until you really ran the RPMs up. This tells me that you may not have the correct valve springs and/or spring setup. If you don't have enough spring pressure to control the valve, then you have massive 'float' at high RPMS - that causes the valve to hit the head . . . and carnage can result.

In order to correctly setup the valve train on an engine like this, one needs to know:

1) Valve spring specifications
2) Installed spring height
3) Spring pressure on the seat and open (given the cam).

AND - all the above, needs to be setup correctly . . . my guess . . . none of that was done.

Your problem can easily be caused because somebody put in very light valve springs (stock), didn't check the on-seat pressure, so you ran the RPMs up and floated the Hell out of the valves. They can only beat into the head for so long - before 'Pop Goes the Weasel' . . . and the tops pop off (especially with economy valves - where the heads are welded on).

Okay - that is my best guess . . .

 

You are probally dead on!!!


Was hoping that I could remedy this as cheaply as possible..... But doesn't look like it is gonna happen I pulled the lifters out one at a time of the valves that made contact and the one that broke caused a very slight nick? in the center of the very top of the cam lobe. The lifter still feels nice and smooth but I can just catch my fingernail on the center highpoint of the cam lobe. So my cheapening out on the valves and springs cost me this motor.

Thanks for all your help but I think I am just going to cut my losses and move on....at this point I can't even look at the car without getting infuriated with my stupidity!!!

 

Naw - don't do that - you had the engine running and it really ran well - so now you know what it feels like . . . so remember that and just get it fixed the right way!.

PS: That 'nick' is probably because the valves floated and came banging back down on the cam. You should be able to polish them a bit with a flat piece of wood and some 400, then 600 grit wet or dry. If you have doubts - send me some close up pictures.

Since the valve seats should be good, just go to Red's Headers or VanPelt - and get a good quality set of valves, get the good springs (I'd run either isky 185Gs or Zephyrs) and setup your installed spring height to give you about 75 lbs on the seat (you can probably get by with a bit less, but this is where I'd go). You'll need to have a machine shop test the springs to give you the correct installed height that you'll need - then setup your valve/guide/spring/retainers with the correct amount of shims to meet that height (obviously in the block). Now - you'll have enough spring pressure to control the valve at higher RPMs - and it will run well. I imagine you can do all of this for $200 - 300 (including parts). Yes - it is money you didn't want to spend, but you have a brand new engine that just needs a BIT more work to get it right. Stick with it . . . you'll be glad you did!

If you need help, ping me . . .

B&S

 

Also, the Big Flathead God in the sky must have wanted this motor back together - he didn't allow the valve head to work it's way down into the piston crown and beat the shit out of the heads, piston, bearings, crank . . . you get the picture. I would carefully checkout the valve seat for that valve - just to make sure the seat is not damaged.

Get it fixed - get it back on the road and have some damn fun!

 

Here are the 2 lobes with pitting, one other one has a pinhole looking pit on,the same spot as well.

As well as the lifter that was riding on one of them.

 

The pitting is pretty deep I would think it is too much to sand out? So in order to fix it it look like new cam and new lifters?

 

The pitting on your cam makes it junk. You need both lifters and cam and to find out why it happened. Gary

 

I was cheap on the valve springs and valves and paid the price.... I just ordered a new max 1 cam, hollow adjustable lifters, stock replacement valves and 185g springs.... So unless someone takes the pos of the hands before I get the parts I am going to make one last attempt to make it right.

 

You should just get the reds headers pro flow stainless valve kit. It will come with everything you need plus good parts. Comes with the shims to set the spring pressure. Make sure you do that. It's like 400 bucks. Add up what the springs and shims and valves your buying and if it's close to reds kit price spring for the reds kit. Manley makes some of the best valves out there. Flatheads aren't cheap but they sure are cool.

 

Good for you! Keep at it , that flathead will suprise you ( in a good way ) Gary

 

I agree with PaintSlinger - buy the better valves . . . they're a better product for sure . . .

 

I already ordered stockers from reds headers... I saw the high flow ones for over 2 times the price and really don't have money.... My tab was already over 900 with just the crap I "need" to attempt to fix this piece of junk.

I am still hoping someone buys the thing before I mess with it again to put me out of my misery!

 

Hang in there and remember the smiles from a while back, you will be glad you kept at it when you get it right!

 

Sorry to keep asking questions but how exactly to I determine the correct spring hight to tell the local race shop to measure my new spring at?

This is new to me. I assume I lap in the valves first then install everything and measure the hight of the spring when on the base circle of the cam... Then take the springs out in order with each individual measurement?

 

you need a hydraulic spring tester. tell the shop you want your springs installed at whatever pounds initial you want. they will determine the installed height by what the spring tester tells them. then you test fit until you get it about where you need it.