6mustang6

Ok guys, I'll apologize now if my post seems to go every which way. I installed roller rockers on my original heads I just had rebuilt. They are the small chamber 289 heads. I also have upgraded valve springs because I have a comp cam xe274 cam. So long story short, after a few revs I find I have a bent exhaust pushrod on cylinder 4. I thought maybe it was due to the rocker being too loose and bent it. Installed a new one and readjusted the rockers. Cranked it up again and it sounded ok(few light ticks). Took it down the street and then i heard the clacking again. Pulled the cover and the same push rod bent again.. WTF?! So I did some research and my roller rockers say they require guide plates and hardened push rods. I can't install guide plates because i dont have screw in studs. So is this my problem? Since these rockers aren't self aligning I'm guessing they are moving around too much and causing it to bend my push rods, but why is it only one doing it?

MonsterBilly

I have a long wright up on this. You have to use guide plates and screw in studs and hardened push rods.
Therefore, you must take your heads back off, have the studs pulled out, the head measures and machines down and the holes threaded so you can install the Sep studs and guide plates. It totally suck but it is the Only Way.
I ended up with over $900 into my stupid stock heads. If I can offer one piece of advice, stop putting money into them now and buy a set of afr or trickflow heads. You will not regret it.

Search my threads and you will find very specific and detailed info on what you are currently going through

MonsterBilly

If you live near me I will sell you my heads with everything done to them already.

kenash

Nicely stated MB! +1

dklistul

I think the pushrod is hitting the side of the pushrod hole in the head (due to the different pushrod angle with the taller roller lifters). Old 289 heads had a pretty small hole. Newer heads have a bigger pushrod hole but then need the guideplates.

I think you need different heads, not just screw-in studs and guideplates.

Sorry. . .

MonsterBilly

DKLISTUL you are close and correct. the pushrod is hitting the side of the hole. But, the holes on the 289 heads are not perfectly round. they are oblong. This is addressed when they are machined for the screw in studs and the guide plates. they too are to be drilled out. As i stated above, there is a very detailed thread about what I went through and what must be done to get them to function perfectly.
The result is about $600 in machine work and Just over $200 in parts to get them correct.
Therefore, you will have at least $800 into the heads when you can get a really nice set of aluminum heads for a couple hundred more.
I know this because I went through this last year. I spent all the money and went through all the trouble to get mine right. Then decided to get with a set of aluminum heads. The steel 289 heads now sit fully worked over, on a shelf as a reminder to me to just do it right the first time.

6mustang6

MonsterBilly, I have read your threads about this problem. My question is, if my buy self aligning roller rockers that don't require guide plates, will this fix the problem? I can't afford aftermarket heads no matter how much I want them. Comp cams sell a set of rockers that align themselves to the valve and doesn't require guide plates.

Al Newman

Don't mean to step on your thread, but, if your heads have slotted push rod guide holes, you should not use the rail style or self-aligning rockers. If the heads have round push rod guide holes, the rail style rockers should solve your problem.
As for the #4 valve bending a push rod, check to be sure that the rocker is not being interfered with by the valve cover oil baffle, if there is one. The baffle would be freshly scarred, if so. That fix is to "re-design" the baffle to allow clearance. DO NOT remove the baffle completely, as you will then suck oil from the motor via the PVC valve.

MonsterBilly

It will work but its only going to be a temporary fix the problem is with the upgraded valve springs you put in your going to end up pulling out the press in studs on the factory heads

Jonk67

Looks like the XE274H has a lift of ~.520, I've often read that close to or past .50 lift on stock pressed in studs will eventually pull them out as they aren't intended for that much lift. With that cam I think anything other than screw in studs will be a temporary bandaid.
Heads are an expensive learning tool for many of us unfortunately but they are the key to a good breathing Ford and are the achille's heel in stock form.
Jon