Began to assemble the HEMI... UPDATE 16/12-2007 and situation FUN again....

[Mefirst]

Tom, are you using a higher ratio rocker arm ? 1.6:1 ?

Those hemi rockers aren't cheap ! 

Ron

Ron

No, the rocker arms are standard, 1.55:1 I believe... -Yeah, a new compleat set of rocker arms cost a fortune, but still, a new set would be cheaper than having to rebuild the engine, if one or several rockers fail...

/Tom

[firefighter3931]

Tom, are you using a higher ratio rocker arm ? 1.6:1 ?

Those hemi rockers aren't cheap ! 

Ron

Ron

No, the rocker arms are standard, 1.55:1 I believe... -Yeah, a new compleat set of rocker arms cost a fortune, but still, a new set would be cheaper than having to rebuild the engine, if one or several rockers fail...

/Tom

Tom, Rocker arm geometry has allways been a known issue with hemi motors....it's difficult to get them just right ! 

What rockers are you using ? Rollers ?



Ron

[Mefirst]

No, they are mechanical..



..so this is really "Ol´School" I also noticed when I linked the pic that these type of rockers seem to have a ratio of 1.7:1 for intake and 1.65:1 for exhaust, so I´ll have to check again the ones I have...

About the geometry... -True, nothing seems to line up right, it just looks weird... When you drop in the pushrods into the lifters, the angle the pushrods are in, well it looks just weird. The pushrods don't have enough space to move about when you rotate the engine. Like I wrote in my earlier post, I knew this might become a problem, but I did not think it would be this serious. I have to "grind" off material from the heads to get the pushrods to move with out hitting anything... 

/Tom

[firefighter3931]

The larger ratio makes sense.....that's usually the case, even with wedge heads. As the Ratio increases the pushrod tunnels need more clearancing. If the cam is very agressive this only aggrivates the problem.

Some of the old school iron adjustables weren't really designed for high lift roller cams and the sweet pattern across the valve tip can be all fubarred. 

I'm not a hemi expert but i would suggest you run this by someone like Tim Banning at FHO for some feedback. 



Ron

[Mefirst]

The larger ratio makes sense.....that's usually the case, even with wedge heads. As the Ratio increases the pushrod tunnels need more clearancing. If the cam is very agressive this only aggrivates the problem.

Some of the old school iron adjustables weren't really designed for high lift roller cams and the sweet pattern across the valve tip can be all fubarred. 

I'm not a hemi expert but i would suggest you run this by someone like Tim Banning at FHO for some feedback. 

Ron

-So true. The roller cam that was used in this engine was a real animal. The heads have had machining done to them for more pushrod tunnel clearance, but problem is that that clearance work was done in a different angle, than what is needed to get the clearance for the hyd.cam push rods I plan on using...

About the rockers... The tips of the rockers have seen better days, thats the main reason I have to buy new ones...

/Tom

[firefighter3931]

Tom, just so we're on the same page  ....what cam are you planning to run in the hemi ? The same roller or something milder ? You mentioned hyd pushrods in your last post.


Ron

[Mefirst]

The cam im using is a hyd. roller cam from Crane # 669551

Link... http://www.cranecams.com/

I do also have the former roller cam, but Im not planing on using it.. # 669091

I also have the former hyd.cam that was in the engine when I bought it..

Comp Cams 305H10 Hi-Tech hydraulic camshaft
Adv. Duration:305 Int. 305 Exh./Duration at .050 253 Int. 253 Exh./Lift .550 Int. .532 Exh./Lobe separation angle: 110

/Tom

[firefighter3931]

Tom, did you see these notes at the bottom of your cam's spec page On Crane's website ? 

Remarks:
DUE TO THE INCREASE IN PUSHROD SEAT HEIGHT, THE CYLINDER HEAD AND POSSIBLY THE BLOCK WILL HAVE TO BE MODIFIED FOR PUSHROD CLEARANCE. 

That looks like a very nice grind.....should make killer power in your hemi ! 

There's a company in California called RAS which stands for "rocker arm specialists". They recondition iron rocker arms....adding bronze bushings, correcting ratios, resurfacing contact pads etc.... I would be sending the rocker arms to them before buying anything new....probably save yourself a few grand. 


http://www.rockerarms.com/index.htm



Ron

[Mefirst]

Ron

-Yeah. I did read the note about the cam. Then again the push rod tunnels in the heads were already machined, so I of course thought that the new pushrods could move about with out any problem...

The guy I bought the cam from, tried it out in his 572 Hemi, his Hemi made N/A some 800HP.. The reason he changed out the cam was he didint like how it made the engine sound and behave, so he changed it out to a cam that was more gentle..

/Tom

[Mefirst]

Update 27/10-2007

Well I'm still trying to get the push rods to move freely through the heads.. -I can only say that this job is a -Bitch I think I have removed at least 5 pounds of material and still the damn push rods hit the push rod tunnel walls in the heads... I started out filing down the tunnel walls by hand, first marking out in what angle the push rods move through the heads.. I cant even explane how much this work sucks .. Remove some material from the heads, place the head on the block, drop in the push rods, drop in the rocker assembly, check the push rod clearance... -Nope, not even close... Start al over again...

Any way, today I kinda "lost it" and used a grinder Then again trying to hold your hand steady when the grinder is turning at 30.000RPM and trying not to remove to much material is not good for your nerves... I would want to say I got the job done... Sadly not, I'm close now, but still need to remove more material... and this is only yet the right side head im working on, still got the left side head to do

-I just hope that using this cam is worth the pain in the a$$

/Tom

PS. Ill take some pics so you can see how much I had to open up the push rod tunnels...

[Steve P.]

Take it slow brother.. I like to use a block of wood as a hand rest. It makes it easier to control that monster..

Good luck.. 

[Mefirst]

Take it slow brother.. I like to use a block of wood as a hand rest. It makes it easier to control that monster..

Good luck.. 

-Im as delicate as if I was doing brain surgery... 

/Tom

[Steve P.]

Come on... You CAN'T use a cleaver on your heads....   

[Mefirst]

..the project continues.... 28/10-2007

Todays accomplishment... -Almost, but still not enough ... Then again I can now rotate the engine, but al of the exhaust and one intake push rod are still to close to the push rod tunnel wall.. -Yes they do move about freely, but still not enough room to move, that Id feel comfortable rewing the engine up to 7000RPM -Damn, I wouldnt even let it idle before I can get the push rods to move more freely...

Here are some pictures... Just so you can see how much material I have had to remove from the heads...





/Tom

[Steve P.]

Holy bottomless pit, Batman...     Are you using 1/2" diameter push rods or what??  Looks to me like you should own a mill.....  Good luck bro...   

[Mefirst]

Steve

The pushrods are 3/8" in diameter. The problem is the way the push rods move about. Push rods don't move up and down in a straight/linear line, they also move kinda "rotating" (I don't know how to explane this movement in English). Its this "rotating" movement of the push rods that cause the problem...

/Tom

[Steve P.]

Hehehe.... I know how they work, Tom. I was busting your chops.. It really does look like a mill would really help..

[Mefirst]

Hehehe.... I know how they work, Tom. I was busting your chops.. It really does look like a mill would really help..

I think with the amount of aluminium Ive removed from the head, I think it would be almost enough to cast a new piston.. well a small one at least.. Wish I had a CNC machine, that would make this alot easier, well after figuring out how to set up the CNC machine so it would remove material from the right spot...

/Tom

[firefighter3931]

Geeez....that's a major pain in the azz ! 

Keep at it Tom ! 


Ron

[Mefirst]

UPDATE 9/12-2007

After allot of time spent removing aluminium from the heads, the pushrods finally move about freely

I test assembled the engine with both heads and valvegear and everything seems to bolt on perfectly. The engine is also easy to rotate, well once the sparkplugs are in place, my bet is that its gonna be a bitch to rotate cause of the high compression (about 12.8:1 something)

I also took the heads appart once more to clean them from al of the aluminium dust left from the grinding work...

Here are some pictures...







I'm gonna assemble it completely next Sunday and hope that I wont have to open it up again for some time. Then again I'm probably gonna open it up after the summer season 2008, just to check everything, cause it is after al a race engine, so it needs allot of TLC....

/Tom

PS. The car in the background of the first picture is my buddys 69 Super Bee...

[firefighter3931]

Tom  that's looking really good ! 


Ron

[yeahitsgotahemi!]

That oil valley is really smooth and shiny, is that some type of epoxy to smooth it out and help with oil flow?

[Mefirst]

That oil valley is really smooth and shiny, is that some type of epoxy to smooth it out and help with oil flow?

Its just a thick layer of paint. The engine is an old Pro Stock race engine. Engine builders many times paint the valley to smooth out the walls. The idea behind this is that the oil will flow faster down into the oil pan.. I have no idea if this is just some kind of "Voodoo", but many Stock and Super Stock engine valleys are painted for this reason... Its also belived that it would generate a little more power..

/Tom

[Mefirst]

Update 16/12-2007

The heads and valvegear are officially bolted on as of today.. Next job will be to fit the Indy intake and walleypan, which will most certainly again be one of those projects .. Ill start with that project come January 2008...

Here are some pictures for those interested...



I also tried to take a pic so you can see how BIG the intake runners are (Did some port work on them earlier).. I can almost fit my hand into them For the Fuel/Air mixture its more or less a straight drop from the carburator into the cylinders..





/Tom

[firefighter3931]

Very impressive Tom ! 

That single 4bbl manifold looks like a tunnel ram ! 

It's amazing to see how strait the runner to valve path is on these Hemi motors. That will make some killer top end power !!! 


Ron