Do it ur-self 1.6:1 /6 rockers

[Bill Dedman]

These are some really poor photographs of my attempt to create some do-it-yourself 1.6:1 rocker ams for our /6.

I apologize for the crummy photo quality.

Hope these rockers work better than my camera...


We used a .102" metal-cutting saw blade from Manhattan Supply (MAS) to make the cut. The jig (holding fixture) was fabricated by yours truly and looks like it... but, it worked. They were cut an a Bridgeport-clone vertical mill.

The two pieces will be t.i.g. welded back together next week.rayer:

Wish me luck...

Hope this is of interest to someone.

 

[srixon4406]

Here's mine Bill

 

[Bill Dedman]

That looks good, Aaron. Thanks for the photos!!!

Tell me about what sort of welding process you're going to use to put them back together, please....

 

[srixon4406]

Bill I plan on just tig welding them back together the pic on the bottom is one I tacked back together with a mig welder and will probably do the rest the same way then just tig them back together and heat treat them and test them out. What did you plan on doing if we need a longer push rod?
Keep up the good work you and Freddie inspire you
Aaron

 

[Bill Dedman]

Bill I plan on just tig welding them back together the pic on the bottom is one I tacked back together with a mig welder and will probably do the rest the same way then just tig them back together and heat treat them and test them out. What did you plan on doing if we need a longer push rod?
Keep up the good work you and Freddie inspire you
Aaron

Aaron,

Those rocker arms as they come from the factory, have a "ridge" on top, that runs across the whole length of the rocker arm. If we weld the cut-off piece back onto the arm with that ridge on the same level as it was originally (with the top of the rocker "ridge" continuing all the way to the adjuster-screw "boss" at the same height as it was originally, I don't see how the pushrod length could be affected at all; all we did was to move the adjuster screw .100" toward the shaft. That should not affect the length, should it?

Yes, it will "lean" a little. but the change in angle will be VERY small. Probably couldn't see it with the naked eye.

I don't think pushrod length will be an issue at all. Just my 2-cents...

What amazes me is how similar our cuts were... look like they are from the same batch... LOL!

 

[srixon4406]

I wasn't sure about the pushrod length TOM made mention about running the adjuster screw almost all the way down on his design wasn't sure about how we did ours
I lined the top runners even with each other and tacked them back into place
Aaron

 

[Bill Dedman]

I wasn't sure about the pushrod length TOM made mention about running the adjuster screw almost all the way down on his design wasn't sure about how we did ours
I lined the top runners even with each other and tacked them back into place
Aaron

I never understood why Tom had that problem, but if you weld them back like you said, ("I lined the top runners even with each other and tacked them back in place") I don't see a problem, since the adjuster screw is still in the same plane (level.) That was my plan, too...

We'll see, I guess...

 

[Shaker223]

I never understood why Tom had that problem, but if you weld them back like you said, ("I lined the top runners even with each other and tacked them back in place") I don't see a problem, since the adjuster screw is still in the same plane (level.) That was my plan, too...

We'll see, I guess...

That's what I thought too. The only thing I can assume is...since the adjuster was moved closer to the fulcrum, the lengh of needed push rod was increased because I moved the adjuster further away from the factory centerline.

 

[Bill Dedman]

That's what I thought too. The only thing I can assume is...since the adjuster was moved closer to the fulcrum, the lengh of needed push rod was increased because I moved the adjuster further away from the factory centerline.

Tom, thank you for that expanation.

I'm gonna try this with stock pushrods. If I have to buy some longer ones, well, I'll just have to do that.

I'll let you know, but it will be awhile.

 

[805moparkid]

ok guys i am gonna make a jug and try to bang ome of these out... i have all the tools at my despoal but not the time...

something to also think about are the inside diameter's of the rockers...

some are nice and dont wobble and others are...welll... worn out...

is there any precivable way to either cut and make a new sleeve or bush them??

and Bill... your jig is just along the lines of what i was thinking...

 

[805moparkid]

also dose somebody have the oiling diagram just for the shaft and rockers?

i know the tip is oiled thru the groove in the middle but what about the pushrod? isn't there also a hole in there that would be welded up?

 

[Bill Dedman]

ok guys i am gonna make a jug and try to bang ome of these out... i have all the tools at my despoal but not the time...

something to also think about are the inside diameter's of the rockers...

some are nice and dont wobble and others are...welll... worn out...

is there any precivable way to either cut and make a new sleeve or bush them??

and Bill... your jig is just along the lines of what i was thinking...

Ed, if ~I~ can do this successfully, ANYBODY can... I am not, nor have I ever been, "mechanically inclined."

The guy who is welding these up for me runs a CNC machine shop, and just does welding in his spare time (IF he has any.)

Well, one of the motors on his best CNC machine was "going out" so he installed a new one.... guess what? It burned up... so, he had to put the old one back on because he is REALLY BUSY with CNC porting, right now.

Bottom line: He hasn't had time to weld up our rocker arms.

That's okay; we weren't going to ue them right away, anyway.

You can't see it because of the camera angle, but on the back side of tha jig I made, my machinist welded a piece of 1" square tubing about 6" long, to clamp in the vise on his vertical mill, to firmly hold that fixture from moving. That is how we located the jig on the bed of the mill. It worked!

The metal saw blade we used was niminally .100" thich, but it was actually about .104".

Unless you are planning a turbocharged engine for your car, I don't think the problem WE have of not being able to buy a cam with sufficient lift at the valve (say, a little over .500") would be a problem for you. The cam grinders all tell us that the lift ramp is too steep, if you try to grind a cam with only 210-degrees duration at .050"-lift and lift the valve over half an inch.

Long duration cams, such as yours, don't need that steep an angle for that valve event, so 1.5 rocker arms work okay for that application.

Do you agree?

 

[805moparkid]

Ed, if ~I~ can do this successfully, ANYBODY can... I am not, nor have I ever been, "mechanically inclined."

The guy who is welding these up for me runs a CNC machine shop, and just does welding in his spare time (IF he has any.)

Well, one of the motors on his best CNC machine was "going out" so he installed a new one.... guess what? It burned up... so, he had to put the old one back on because he is REALLY BUSY with CNC porting, right now.

Bottom line: He hasn't had time to weld up our rocker arms.

That's okay; we weren't going to ue them right away, anyway.

You can't see it because of the camera angle, but on the back side of tha jig I made, my machinist welded a piece of 1" square tubing about 6" long, to clamp in the vise on his vertical mill, to firmly hold that fixture from moving. That is how we located the jig on the bed of the mill. It worked!

The metal saw blade we used was niminally .100" thich, but it was actually about .104".

Unless you are planning a turbocharged engine for your car, I don't think the problem WE have of not being able to buy a cam with sufficient lift at the valve (say, a little over .500") would be a problem for you. The cam grinders all tell us that the lift ramp is too steep, if you try to grind a cam with only 210-degrees duration at .050"-lift and lift the valve over half an inch.

Long duration cams, such as yours, don't need that steep an angle for that valve event, so 1.5 rocker arms work okay for that application.

Do you agree?

well here in something i learned from an SS/AH guy... everyone is so caught up in max lift in the head... and as most people say you want good low lift numbers with the good peak numbers for a good all around head...

so lets say in the case of the slant it flows its max at .550 (example)...

when you have a cam like mine .475 vlve lift/246 @ .050 it travels thru its "bell curve in X amount of time... now if you get some really big rocker ratios up top and a low duration (duration for correct rpm range) then you throw as much lift as you can get at it...

and here is why... as you know on an NA motor its all about pressure differential... so you want that valve open fast... so throw 1.6 or 1.7's on it EVEN if the numbers exceed the top flow of the head...

and here is why again... as everyone already pointed out low lift numbers are key, so with a super lift cam not only is the bell curve bigger (the valve will be held open longer) but the cam will be in the low to mid lifts longer...

so instead of a conventional ^ like a flat you start looking at a roller profile where the cam lobe kinda looks like a mushroom lol...

so im gonna try to make a set of 1.6's for giggles... also want to see first how much exhaust lift there needs to be on my current motor... so im gonna re-lash the exh out to like .025 and see what happenes...

and no i cant get a good lift cam without going with way to much duration...

 

[RustyRatRod]

Keep in mind what all the guys did running lift restricted classes. Duration and lobe sep can mean a frikkin LOT. While lift is certainly important, you don't have to have to to run well.

 

[bohica2xo]

Nice work on cutting a rocker arm down, hope it works out for you.

I am not a slat six guy, in fact I can't recall the last time I saw one in pieces - so let me ask this question...

What is keeping you from adding roller lifters or mushroom flat tappets to the engine to solve the lift vs duration issue?

I understand that sometime there is not enough room to put rollers in some blocks, but a mushroom will usually solve the problem just as well.

Does the slant share a common lifter with other mopar engines?

B.

 

[805moparkid]

Nice work on cutting a rocker arm down, hope it works out for you.

I am not a slat six guy, in fact I can't recall the last time I saw one in pieces - so let me ask this question...

What is keeping you from adding roller lifters or mushroom flat tappets to the engine to solve the lift vs duration issue?

I understand that sometime there is not enough room to put rollers in some blocks, but a mushroom will usually solve the problem just as well.

Does the slant share a common lifter with other mopar engines?

B.

all the lifter are the same... /6,SMB,BBM... i already looked into a 1" mushroom lifter and got cam specs of a .408 lobe with 252 @ .050 duration...

much better than my .340 lobe with 246 @ .050... but i really dont want any more duration...

i would prefere not to rev mine over 6 so i really dont want any more duration...

 

[srixon4406]

I got five of these done and all tig welded up in my spare time

 

[Bill Dedman]

I got five of these done and all tig welded up in my spare time

That looks GREAT, Aaron! How long does it take you to weld one up? The guy who is doing ours isn't talking at this point; guess we
will get 'em when we get 'em.... not that we a could use them right now, anyway...

 

[srixon4406]

Bill it takes me around a half hour to weld each arm I've been doing two to three passes a side. But there's some cool down time in between each pass though
Aaron

 

[Bill Dedman]

Bill it takes me around a half hour to weld each arm I've been doing two to three passes a side. But there's some cool down time in between each pass though
Aaron

Thanks, Aaron. That gives me some idea of how much to pay this guy who's welding (T.I.G) up ours.

A time-consuming process...:-?

 

[Bill Dedman]

Nice work on cutting a rocker arm down, hope it works out for you.

I am not a slat six guy, in fact I can't recall the last time I saw one in pieces - so let me ask this question...

What is keeping you from adding roller lifters or mushroom flat tappets to the engine to solve the lift vs duration issue?

I understand that sometime there is not enough room to put rollers in some blocks, but a mushroom will usually solve the problem just as well.

Does the slant share a common lifter with other mopar engines?

B.

There are a couple of problems regarding roller lifters in slant sixes.

1. There are NO commercially-available slant six blanks for roller cams, but you can get one ground for a cool thousand dollars.:angry3:

2. Once you get the cam ground, you have to acquire a set of workable roller lifters, and devise a way to anchor the lifter bodies in the block to keep them from rotating on their axes.

3. For our particular application (turbocharged) the rpm's are limited to 5,500, so a lot of valve spring pressure is not required to prevent valve float/bounce, relieving us of needing potentially cam-damaging spring pressure. A roller cam is not needed for longivity, in this instance.

4. The problem with excessively steep lift ramps to get the desired amount of lift with short duration cams, can be dealt with by the use of higher-ratio rocker arms. Ours are 1.6:1 (stock is 1.5:1, nominal.)

So, in the final analysis, there seems to be an alternative to roller cams for at least, OUR slant six.

I am too ignorant about mushroom lifters to comment on them.

Hope this explains something about the roller-lifter deal for slant sixes.

Thanks for your interest!

 

[RustyRatRod]

All this looks great but has anyone actually put one of these in an engine and measured the lift at the valve?

 

[Bill Dedman]

All this looks great but has anyone actually put one of these in an engine and measured the lift at the valve?

I haven't gotten mine back from the welder, but you can rest assured that when they go on the engine, I will do the "lift test" and report it here. I'm curious, too!

 

[RustyRatRod]

I am sure it cannot help but be an improvement, but my curiousity stems around consistancy. If they were not consistant before.....

 

[6pakattack]

"and no i cant get a good lift cam without going with way to much duration..."

Did you ever give Charlie at CamCraft a call to see what he could do to help you ?

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