Well long story short I had some 243 castech heads on my car with tv2 cam. Made 438hp 405 TQ with Pat g tune on the dyno. Had a valve spring crap out on me a year later went to replace all of them and found out the rocker bolt holes all are helicoiled. Now my rocker bolts won't torque down. So now I'm looking at as cast 220 heads at 58cc from Brian tooley with some work from him and with pm guides so I can run stock rockers. I have -4cc mahul pistons. First question how are the heads holding up with stock rockers with truinion upgrade? I have done my research everything is from 3 years ago it seems like. Also should I change my tourquer v2 cam to something else while I'm at it? Think that cam is a bad choice for those heads?

My head seem to be holding up pretty well.

What are the specs on the cams?

I know what you mean about all the info being three years or older. I made a thread recently about these heads and it didn't catch much traction.

i ended up getting with tony mamo and ordering his 223 sportsman heads

How do you like them? Any numbers?

have not got them yet. Im hoping for a big improvement, i went with 57cc and changing to yella terra roller rockers. also hollow valves. should be a good increase from the 243 heads. it will be a few weeks maybe a month or two before its back on the road. ill be getting pat g to tune it again, after ill post the numbers.

jtm the mamo heads are a little more than the as cast 220 but i have a good feeling they will out perform the as cast 220 by a good bit.

I hear ya. I liked the Mamo heads but I really want to stay with stock rockers at the moment

Excited to see your results! Good luck!

Just to clarify, you certainly can run stock rockers on the MMS 220, MMS 223, and the MMS 235 cathedral heads

I just recommend to folks that they don't because OEM rockers will side-load the valve stems wearing out your guides prematurely and reducing the service life of the expensive heads you just purchased

This negative situation isn't exclusive to my heads....the same will happen with any aftermarket or OEM castings with .600 (or more) lift and twice the spring pressure of a stock OEM set-up.

And a trunion upgrade does nothing to correct this which IMO is the largest problem inherent in running the OEM rockers (poor geometry and a square shaped contact patch across the tips of the valve versus a much more desirable narrow rectangle in the center of the valve for a well designed aftermarket roller rocker like Yella Terra and the like).

Just didnt want other reading this thinking they were forced to upgrage rocker arms running my heads....they are not.....its just a smart upgrade for all the reasons I previously mentioned!



Happy New year guys!

-Tony

Tony, can you set the heads up with PM guides to help with stock rockers?

Yes....at an additional cost but that's not the answer either.....it only slows down the hour glass taper that occurs in the guide from the side-load of the valve with the OEM rocker.

Your money is better spent eliminating the problem (by upgrading rockers).....not by placing a band-aid over it slowing down the inevitable wear by using a slightly tougher material (with less lubricity btw).

A high performance engine is a system.....the better you design the system as a whole the better your results. An OEM rocker was/is fine with .470 lift, soft gentle ramps on the cam, 80 lbs of seat pressure and 200 lbs open....it works.....but its out of its element when you start getting into alot more lift, alot more camshaft lobe intensity (modern day performance cam profiles), and the springs required to control all of these elements (which yield about 2X the spring load of stock aggravating the sideloading).

Sure....you can run stock rockers but anyone who makes an argument that they are ideal are only kidding themselves and the guys less educated reading this. A wide wipe pattern (a "square" shape visually versus a rectangular patch) and the additional side-loading of the valve stem and subsequent guide wear in a performance environment will never able to be fixed/eliminated if you choose to run the OEM rocker set-up.

Knowing and understanding the "why" of all this is power....what you do with that knowledge is up to you. If you want to optimize things you have to step up to gear better designed to cope with that environment improving the overall "system" of components I mentioned earlier and ultimately your results and most importantly the longevity of the investment in your cylinder heads

I hope some of you benefit from this post....

And to reiterate....this is an issue related to ALL heads regardless of the letters on the endpad

-Tony

Thank you for the detailed response Tony.

Tony, regarding the side loading issue with stock rockers a couple of questions if you have spare moment:

With .600+ lift, is it possible to improve the wipe pattern of the stock rockers by shimming them?

Would an 224 XE-R cam with .581 lift and 370 pounds of spring pressure have enough side loading geometry issues to merit upgrading to Yella Terra's?

Thank you.

This is likely off topic, but imma say it anyway. I know this wasn't supposed to be a rockers thread.

Stock rockers sort of "roll" over the valve stem. If you really look at the pattern and where the rocker touches the valve, you lose ratio at lower lift. In other words, on a stock rocker, you only have 1.7:1 at peak lift. You're giving up low lift.

You don't just make power at peak lift. So there are advantages in power beyond the longevity of the guides. In truth I think you leave power on the table to get really good heads and then leave the stock rockers in.

As Darth touched on the shape of the rocker pad of an OEM rocker cant help but make alot of contact with the valve tip (starting from the intake side and swiping across center to the exhaust side). My guess is shimming will simply move the swipe more than make any significant differences in regards to making it more narrow.

To anyone on the fence regarding the decision to go roller or OEM, my advice is to save longer and do it right the first time....don't leave the extra HP on the table and don't shorten the life of your heads.....the largest single investment you will make when it comes to your bottom line horsepower

I wouldn't even consider building an engine for myself with stock rockers....as a serious gearhead and a guy that likes to optimize the engines I build it would make me cringe at that thought. I say this only to convey how passionate I am on this subject and I know I have converted a few guys on the fence who have all thanked me when the smoke cleared.

Like it says below everything I post

Build it right the first time....its alot cheaper than building it twice!!

This certainly applies to this situation!

-Tony

Tony, thank you. I will probably replace the stock rockers on my 99 TA when doing valve springs this time around. May pull the TEA 5.3 heads & freshen them up as well after 120,000+ mile with xer cam as well. It is always better to check parts 3x times and do it right the first time.

Yeah, there will soon be a problem with your 10 bolt.

im in the same boat i would love to get mms223 but i dont want to spend the extra money on rockers(my budget is pretty decent)but i dont want to go overbudget on my car i drive less than 3k a year and take it to the track a couple times in the summer.