M90 rebuild (rudy)

[jd4242]

Wow, that could be a huge issue.
Assuming noting smacks together, I wonder what your compression will be.

This sounds horribly wrong. I see why you are so concerned.

Nothing should. The pistons dont have valve reliefs cut into them but are dished.i know normally it doesnt matter if a valve hangs open because you have plenty of clearance. .

Remember my other motor the delta rockers broke and held my valve WIDE WIDE open.i had the 422 cam (.500) lift,SI stock size valves and felpro gaskets (.035-.040 compressed measurement) and i didnt have any damage.

I think the valves being larger they come closer to the edge of the dish where it starts getting shallower. I also have .067 more lift with the 1.7 roller rockers..the pistons barley come up farther than stock,its minimal but add everything else into play and things get tight..this block also probably has been milled before and thats why the pistons come up farther than spec..also the heads have been milled..

We made the copper gaskets thicker to add some room for think was piston thirst or something (cant remember the term) but if worse case happens and a valve hangs i ""SHOULD"" still have room to spare..""SHOULD""......

Now if he mills the head more things change,depending on how much..that cushion may disappear. .

Also there is a max spec on how much the o-ring can protrude into a certain thickness copper gasket.that link i posted tells the spec,have to look it over..im pretty sure i wasnt close to the max for .050 gaskets which means the head can be milled a certain amount before the oring grooves have to be recut..

Again its all very tight specs and every number effects a different item.. domino effect..so i need to sit down with the owner and go over all of our "blueprints" and specs.

 

[jd4242]

Quote. ..

""""""""The wire rings are typically .041" in diameter, and are placed in a .039" wide x .030" deep groove. The wires should protrude only about about .010" above the surface of the deck, and the thickness of the gasket should be about four times the protrusion of the wires in their grooves, or about .040"..."""""""""""

So my wire can protrude .125 out of the head for my .050 gaskets. .

 

[malohnes]

It's really rather disheartening to see so many quality control issues with what should be simple machine shop work that any hi-performance.shop "should" be able to perform without troubles. Your background has been invaluable to your project in making sure certain details are appropriately handled, that appear to not have been. Amazing the world still runs these days.... I'm rooting for you and your project.

Did you ever get the 1.7 Morana rocker kit installed to your satisfaction - I recall issues with the rocker mount machining a while back?

Thanks for sharing all this info, JD...it's making those of us who are going a similar route to you a whole lot easier.

 

[jd4242]

It's really rather disheartening to see so many quality control issues with what should be simple machine shop work that any hi-performance.shop "should" be able to perform without troubles. Your background has been invaluable to your project in making sure certain details are appropriately handled, that appear to not have been. Amazing the world still runs these days.... I'm rooting for you and your project.

Did you ever get the 1.7 Morana rocker kit installed to your satisfaction - I recall issues with the rocker mount machining a while back?

Thanks for sharing all this info, JD...it's making those of us who are going a similar route to you a whole lot easier.

Im sure he has his reasons and im sure whatever he says will work,will work.i do trust this guy and hes been 100% honest with me every since i started dealing with him..he has done all my motors and he goes way back with friends and family. .


I have ordered longer arp bolts and made spacers for the support bar BUT AND BIG BUT...i have meet someone else that has his 1.8 kit and 410 cam,he is having serious issues ..he keeps breaking the plate and or the bolts holding the support plate or the rocker studs themselves. .he has been back and forth with Tom for over a year and Tom keeps sending him new plates..
NOT GOOD..very nervous about Toms kit..

 

[malohnes]

Wow!! What is specifically causing this failure? That's very disconcerting....

 

[jd4242]

Wow!! What is specifically causing this failure? That's very disconcerting....

Noone knows...i personally havent called Tom but i am very nervous about using this kit ESPECIALLY with my motor having so tight of tolerance.

 

[malohnes]

Not good at all. Having to tear into your heads to replace parts is bad enough, even if nothing interferes...

I'm seriously reconsidering this kit now. Not so sure the kit is worth it. But, I wonder if there are others with 1.5 or 1.6 kits that are having this problem. Do you know of any? I may just stick with ported heads, with oversized valves and the 422 and skip this mess, but I really want the roller rockers given how much more efficient they are.

Luckily, I've got plenty time til I start my engine rebuild...

 

[Turdle]

It's simple. That valvetrain isn't stable at all. It seems like the stud "girdle" is dancing all over the place, while twisting.

I don't see anything there to prevent the stud plate from rocking.

 

[malohnes]

It's simple. That valvetrain isn't stable at all. It seems like the stud "girdle" is dancing all over the place, while twisting.

I don't see anything there to prevent the stud plate from rocking.

Funny...The other day I was reading an old online article from Hot Rod (Googled performance roller rocker hp increase) about the subject of shaft vs stud mounted rockers. This seemed to be a normal issue with studs...instability. However this is pretty breakage is severe...

 

[Turdle]

I hate to say this but the older mopar valvetrain , with the shafts similar to the stock 4.0 are rock solid. I wonder if that style could be modified-machined to work.

just blowing it out. I had a beer for dinner.

 

[jd4242]

It's simple. That valvetrain isn't stable at all. It seems like the stud "girdle" is dancing all over the place, while twisting.

I don't see anything there to prevent the stud plate from rocking.

There is the 3 bolts that go into the old pedestal and he now uses 2 head bolts that are tapped and a bolt goes into them..i hated that idea so go longer head bolts for those 2..you have any input or ideas to further help prevent this??

Here is what he is suggesting. .the guy with issues seems to think the cam has too much lift or his pushrods are too long..

You can see the holes arnt even drill in the center and this also makes the bolt weaker..

Again i got long arp head bolts and go all the way through the plate then a new spacer,into head.my spacers are much larger in OD than his also as the head bolt goes through them obviously. ..felt this was stronger. .

I think hes using to hard of metal for the plate also..like how grade 8 is strong but will break when reaches its max..where grade 5 will bend or stretch

 

[Turdle]

I know you are overcoming a lot of things in this build, but I also think this is the limit for this design. You said it yourself, allowing it to flex to avoid breaking. A flexing valvetrain is not going to do good things above 6000 rpm's.

I see 5 fasteners mounted in a straight line down the beam of the stud bracket. It's going to rock no matter what you do, over time the holes are going to distort.

IMO it needs some lateral bracing to the cylinder head to overcome that. I'd work harder at making the shaft rockers work somehow.

 

[Dono]

Looking at that plate, I think Turdle has the win. I think he's right.

 

[jd4242]

I know you are overcoming a lot of things in this build, but I also think this is the limit for this design. You said it yourself, allowing it to flex to avoid breaking. A flexing valvetrain is not going to do good things above 6000 rpm's.

I see 5 fasteners mounted in a straight line down the beam of the stud bracket. It's going to rock no matter what you do, over time the holes are going to distort.

IMO it needs some lateral bracing to the cylinder head to overcome that. I'd work harder at making the shaft rockers work somehow.

Well i shift at 6800 now,new motor is spose to goto 8k

Hmm lateral bracing..hmmm

Shaft wont work as the rockers are at a angle or offset..roller rockers have never worked in this motor,think hart use to make a set also but where all recalled

 

[jd4242]

I know you are overcoming a lot of things in this build, but I also think this is the limit for this design. You said it yourself, allowing it to flex to avoid breaking. A flexing valvetrain is not going to do good things above 6000 rpm's.

I see 5 fasteners mounted in a straight line down the beam of the stud bracket. It's going to rock no matter what you do, over time the holes are going to distort.

IMO it needs some lateral bracing to the cylinder head to overcome that. I'd work harder at making the shaft rockers work somehow.

I wonder if you do keep the plate from rocking or dancing if you will just start breaking the rocker studs off more often

 

[malohnes]

Here is what he is suggesting. .the guy with issues seems to think the cam has too much lift or his pushrods are too long..

I was thinking about this as the higher spring rates for the 422 cam, coupled with the higher leverage of the rocker would exacerbate the instability of the stud mounted valvetrain. I wonder if a less aggressive cam, IE one that doesn't require the high spring rates would cause this. Further, the thought of too long pushrods is also a spot on theory...

I also agree with Trudle and Dono...

Great point on the shaft mounted rockers on SB Mopar engines...loved mine in my '75 truck. Never should have sold that thing...I wish I still had those parts, I'd send them to you to try. You could probably figure out all that on net research thou...might just work.

I'm still going to buy this kit, but I'm going to do it before I rebuild my engine, with stock cam. If it breaks I won't ruin a new engine. My planned engine won't rev like yours JD, nor get additional boost spray either, but its still worrisome no matter how fast the crank spins..

 

[jd4242]

I was thinking about this as the higher spring rates for the 422 cam, coupled with the higher leverage of the rocker would exacerbate the instability of the stud mounted valvetrain. I wonder if a less aggressive cam, IE one that doesn't require the high spring rates would cause this. Further, the thought of too long pushrods is also a spot on theory...

I also agree with Trudle and Dono...

Great point on the shaft mounted rockers on SB Mopar engines...loved mine in my '75 truck. Never should have sold that thing...I wish I still had those parts, I'd send them to you to try. You could probably figure out all that on net research thou...might just work.

I'm still going to buy this kit, but I'm going to do it before I rebuild my engine, with stock cam. If it breaks I won't ruin a new engine. My planned engine won't rev like yours JD, nor get additional boost spray either, but its still worrisome no matter how fast the crank spins..

Yea we talked about the dual springs and added pressure,only thing is both cams require them..if your went with stock cam and 1.8 it would be cheaper just to do a 422 cam and gain more ..

The 5 bolt holes arnt in a straight straight line,the 2 head bolt ones are slightly off set by maybe a inch.lol

My spacer setup is 7/8"OD where Toms are 5/8" with a 3/8" bolt screwing into the head bolt..i also using just a spacer underneath the plate with a lomger arp bolt with a 1.5x.125x.500 washer..im hoping this add size spacer,more solid configuration with more clampimg force will help with the rocking

Also the 3 bolts going into the pedestal have very small heads,im going to add a larger washer under those bolts also,adding some more clamping force..those pedestals are pretty big,if you can get more more on those i think will help....im even considering running a small weld bead on both sides of the pedestal, welding the plate to head pedestal..i think that would keep it from seriously not rocking..

Also Tom is working on a top plate that connects all the studs together. I spacer will be needed for the valve covers though. .

Any input?

 

[malohnes]

We did talk about this, indeed. In my project, I'm piece mealing things and trying out stuff as I go so it's easier for my wallet and gives me more time to try things out in steps, Its also easier to swap rockers than a cam without pulling the engine. Anyhoo...

I think you're doing the right thing by going with a longer bolt with a larger head and larger spacers welded on. Very sensible solution.

The top plate is what I initially thought was breaking, to the point I had to back track to confirm. Anyway it bothers me a bit that this is a solution to his rockers, when they may need more support to begin with. I guess incorporating them together is a complete kit, rather than an add on should be his response, especially considering the price of the kit.

I just looked on Morana's website and he doesn't advertise the top plate anymore...

This, my forum friend, is what happens when you're on the lunatic fringe of hot rodding. I'm strongly feeling like you'll get it working wonderfully...makes me grin from ear to ear thinking about it

 

[jd4242]

We did talk about this, indeed. In my project, I'm piece mealing things and trying out stuff as I go so it's easier for my wallet and gives me more time to try things out in steps, Its also easier to swap rockers than a cam without pulling the engine. Anyhoo...

I think you're doing the right thing by going with a longer bolt with a larger head and larger spacers welded on. Very sensible solution.

The top plate is what I initially thought was breaking, to the point I had to back track to confirm. Anyway it bothers me a bit that this is a solution to his rockers, when they may need more support to begin with. I guess incorporating them together is a complete kit, rather than an add on should be his response, especially considering the price of the kit.

I just looked on Morana's website and he doesn't advertise the top plate anymore...

This, my forum friend, is what happens when you're on the lunatic fringe of hot rodding. I'm strongly feeling like you'll get it working wonderfully...makes me grin from ear to ear thinking about it

He hasnt made the top plate for sale yet

 

[Xeek]

all i can picture is you being the first to have a valve cover girdle lol