Rail Rockers on 289 Small Block Heads

[sleeperstang]

If Rail Rockers were to be installed onto a 1965 with no modifications for the rail rockers what could happen?

I started a post on a problem with my rebuilt engine, and I found out yesterday that the machine shop mix-matched rail rockers and non-rail rockers on my 1965 289 heads. I am under the assumption now that this is the cause for failure. Comp Cams catalog mentions that Rail Rockers can not be used on this type of heads, so my question is......Why?

What is it that can go wrong if this is the case. If anyone has experience with this please post. I'm trying to verify this so that the machine shop doesn't try to void my warranty or get out of fixing any damage.


Thanks!

[Rev]

I think for the 289 heads you need rail rockers (with press-in studs). In high performance applications I think guide plates are preferable. The purpose of both the rail rockers and the guide plates is to keep the push rods alligned with the rest of the valve train.

In high performance applications (heads, cam, valve train) the guide plates will be what you need. BTW, a roller cam conversion may be a consideration if you're building a new engine.

Rev

[Shaggy]

Rec is correct for the most part except there were a few early early model 289 heads(carry overs from the 260) that were like chevys with press in studs and close tolerance pushrod holes to keep all aligned. Look at your heads and see if where the pushrod goes through is touching or is the slot is actually a round hole that would let the pusgrod flop around if the rockers weren't holding it tight.

What was the failure in you motor?

Also if you are doing a rebuild i would go to a new roller block and run a roller cam as well.

[Rev]

Shaggy, were those the hipos that had the small holes in the heads without the rails? Actually, those early heads don't compete with the later after market heads anyway. I think this was mentioned in earlier threads.,

Rev

[Shaggy]

The HI-PO's actually had guide plates (I can't verify that because I have never actually seen a stock set of hipo's) The ones I am talking about were actually made before the 289 existed and a few got carried over onto 289's during the first couple of years of production. I actually have one head like that in the garage.. It has like a 50cc chamber and a 1.65 Intake and a 1.44 exhaust valve in it. They are junk heads except for the fact that they run you compression through the roof... the valves are way to small and very shrouded so by the time you put big valves in them and unshrouded them you would be back at 60 to 64 cc's just like the real 289 heads not the 260 carryovers. You can have the one I got if you want a boat anchor... it came off of a 64 1/2 260 car and edelbrocks went on it when the other head cracked.

[sleeperstang]

I knew that those were the specs for 1965 289 heads, and I know that it was mid-1966 that Ford went to the Rail-Rocker or self-aligning rockers.

The heads that I have are cast slotted and most of the rocker's are the original or conventional type. My question is....What happens when Rail-rockers are installed? What I'm trying to get at is if what happened to my valve is what generally happens when rail-type rockers are installed instead of the correct self-guiding rockers.

In a nutshell what happened is that I order a 1968 spec 302 block for my 1965 mustang, since I know that that year had the highest compression and those blocks are stronger than newer 302 blocks. My last engine had developed rod knock and I thought that I might as well get a decent cam, so I went with CompCams XE256H.

Later when I build my own engine I'll do a roller cam and all that good stufff.

The reason for my post comes down to......Did the machine shop installing Rail-rockers cause my valve to get stuck, or should I be looking for other possible reasons so that when I go on Saturday to take the engine for them to look at it I have a good load of details where I'm sure it's their fault it failed.

One last note is that this was only the second time I had run the engine, I hadn't even ridden the car with it yet!!!

Thanks for the replies Rev and Shaggy!! And by the way, your posts on the cam thread were awesome, especially the graphs you made Shaggy.

[Shaggy]

When you are looking at you heads does the valve stick almost flush with th eretainer or is it sticking "way" above itlike an 1/8 inch or so? if the are sticking up then you have the proper valves for rail type rockers.. Usually running rail rockers on the wrong valves causes the lock to pop out and the vavle to drop into the cylinder... What exactly happend to you head? It sounds like you may have a valve that is not moving at all right now? If that is the case then you more then likely have a bent valve if when it is cold it moves fine but when it warms up it locks then that usually meens you valve guides are to tight.

[sleeperstang]

Right now the valve is stuck in the engine about a 1/4 of the way in and it doesn't come back out, so I believe it is bent.

All the other rockers looked like they were operating ok when I had removed the valve cover and cranked the engine, and this was after the engine had been running for about 20 minutes at high idle.

I was only trying to let it break-in when all of a sudden the engine stops after hearing some metal pinging, like something had collided. That's when I took off the valve covers and had my brother crank the engine, only the #5 valve was stuck and it was tapped a few more times apparently by the piston.

So far that is all I know about what happened with the engine. If you have an idea of what happened, I'd really appreciate it.

The situation is that the engine is under warranty (it was only the second time I had turned it on) and I wanted to make sure that I hadn't done anything wrong when attaching all parts to the long block. The machine shop took care of the long block build up including torquing the heads on and checking spring height.

I just want to get as much info so that this guy doesn't try to dip me by doing some Mickey Mouse job on the engine when I take it to him on Saturday. I really appreciate all your replies.

Keep in mind this is the first engine of ever bought or built up, but I did read tons before doing any of the build up myself and made sure I torqued everything to specs as well as used the best seals and gaskets possible.

Thanks again for your help!

[Shaggy]

It is not the best picture but if you look where my rocker is touching the valve tip you will see that the valve tip is sticking well above the retainer if yours are sticking up similarly then it wasn't the fact that rail rockers were used.



More then likely from what i have read it sounds as though they either didn't make sure your old valves stems were straight and/or they set the valve guide up to tight.

edited argh why won't my pics post????? I used the IMG tag

[sleeperstang]

Shaggy,

Say that they didn't do 1 of those things and that is what cause the failure. It appears that the valve got stuck and then was tapped by the piston.

What kind of damage could this have caused? I mean, when I go tomorrow to talk to this guy, what should I make sure I ask him to do or make sure he checks.

From conversations over the phone he seemed to think that they probably put too soft or short a spring and due to the lift it caused the spring to bind.

Is it possible the the rotating assembly may still be ok, or should I just expect it to be completely gone.

I think we've finally narrowed it down, now I just want to get the fine details as to what to ask/say when I meet him.

[Shaggy]

Okay if you can get them to pay for it then I would make them replace the piston that got hit and fix the heads. and should fix all the damage that would normally be done. Unfortunately if you are experiencing coil bind then what that usually does is wipe out the cam in short order.I still stick with my first instinct of the valve guides be set-up to tight. but what ever the reason make sure they at least fix your head and if they won't replace the piston that got smacked then they need to at least radius the sharp edges from where the valve hit it. If the do the latter I would never put any dope on it because while it would be considered a serviceable part it has weakened crown of the piston. I have run boogered pistons before from dropping a valve and the only real configuration I have personnaly seen any real trouble with it is on Nitrous because it hits instant on unlike of types of induction.

PS if it is not radiused then you will have hot spots that will usually lead to pre ignition.

[sleeperstang]

Shaggy I can't thank you enough for all of your responses.

I have one more thing to note that I found today. I took off the push rod and found it bent, and that's freaking me out. I paid for the cam, but I imagine that if it's their fault then they have to replace it. I'll have to argue with them on that, but do you think that the bent pushrod would indicate a damaged cam?

Thanks again!

[Shaggy]

More then likely the cam is okay pushrods and valve bend pretty easy in comparison to the rest of the valvetrain which means they usually are the sacrificial part. Did they know what cam you were putting in and it specs? If they didn't they may be able to say "Well we set it up for a stock cam and weren't aware that anything different was going to be used"

[sleeperstang]

That sounds good to me.

I took the car and the guy said that if the piston was cracked they would replace it. They pretty much admited it to be their mistake but they didn't check it right then. I'm just glad they took responsibility for it.

They definitely knew what the specs were because I came them the cam in the box which has the specs on it and I made sure I told they guy.

They gave me a ready date of Wednesday, so I hope all goes well. Thank you very much for your replies, this being the first engine I ever bought from a shop and it going bad just had me all anxious and paranoid as to whether it was me that messed it up or it was on them.

Glad all should be over soon!

[Rev]

Maybe I just missed it, but who inatalled the cam and valve train? Whoever did it should have checked for spring bind, valve-piston clearance, etc. That person seems responsible to me for any of the problems you have encountered.

Rev

[Shaggy]

I am glad to hear that it all seems to be working out well.

[HotRoddin]

Originally posted by sleeperstang
I knew that those were the specs for 1965 289 heads, and I know that it was mid-1966 that Ford went to the Rail-Rocker or self-aligning rockers.

The heads that I have are cast slotted and most of the rocker's are the original or conventional type. My question is....What happens when Rail-rockers are installed? What I'm trying to get at is if what happened to my valve is what generally happens when rail-type rockers are installed instead of the correct self-guiding rockers.

In a nutshell what happened is that I order a 1968 spec 302 block for my 1965 mustang, since I know that that year had the highest compression and those blocks are stronger than newer 302 blocks. My last engine had developed rod knock and I thought that I might as well get a decent cam, so I went with CompCams XE256H.

Later when I build my own engine I'll do a roller cam and all that good stufff.

The reason for my post comes down to......Did the machine shop installing Rail-rockers cause my valve to get stuck, or should I be looking for other possible reasons so that when I go on Saturday to take the engine for them to look at it I have a good load of details where I'm sure it's their fault it failed.

One last note is that this was only the second time I had run the engine, I hadn't even ridden the car with it yet!!!

Thanks for the replies Rev and Shaggy!! And by the way, your posts on the cam thread were awesome, especially the graphs you made Shaggy.

The small block used close tolerance slotted pushrod holes and conventional rockers until May 1966, except the Hi Po heads which kept that configuration for as long as they were built (they never used guide plates). After may 66 Ford went to rail style rockers and big pushrod holes. You're right, you can't put rail rockers on heads with the slotted pushrod holes. Reason being you then have pushrods that can't move and rockers that can't move, so unless you have perfect alignment and zero flex something is likely to bend or wear prematurely. Can't say for sure your problem was caused by incorrect rockers, but I'd say it's sure a possibility.
Using both types of rockers on the same head is truely a rookie mistake that shouldn't have been made, but they took responsibility and thats what matters ... it shows they have integrity.