Upcoming Head Gasket replacement

[Lipka101]

I don't know if the difference in rockers is the pedestal or rockers themselves.

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[kleake]

I still have my original rockers, so I can do some measuring, but I think I did this when I originally ran into an issue. It seems like the difference is in the arm and not the pedestal so it might be hard to determine exactly where the change is, but i'll take a look tonight. I do know that my original rockers have white clips holding the arms on, where the new ones have black clips if that makes any difference.

I just spoke to the dealer to get the other 13 push rods on the way, and he was very puzzled as well. This almost cost me an engine and everyone that I have talked to at the dealers have no knowledge of any change. Had it actually cost me an engine, I would have been taking this way up the chain. If you buy a part from the dealer, you naturally expect the replacement to be exactly the same and not have some 'non-visible' change that can cause a catastrophic failure,,,, without being told about the change.

 

[96F350KID]

Ford changed the rocker arms design to prevent the premature wear of the rocker tip. They also changed the pushrod length to stop lifter and rocker wear. A lot of guys get the valves cut instead of looking at the pushrods which is why it's never a larger topic. I didn't even read you had valve to piston contact. The Ford dealer should of noticed the part # was superseded to a new one. Now that you've ran it like that for a few thousand miles you need to replace the lifters and pushrods to make sure you don't have anymore issues. For safe measures they also had the backside of the cam lobe made to shock the lifter and cause it to break as well. Colt Cams can explain it better if you give Geoff a call. Few others know about it too. I don't know how involved you want to get to pop a new cam in it but if it was my personal truck I would. We get people that come to our shop and trucks from other shops that always have poping in the intake and valve to piston contact they can't figure it out after reassembly for head gaskets with new rockers. I'm surprised you ran as long as you did without an issue.

 

[kleake]

Man I am surprised I made it this long too, but I think it's because I took some material off the top of the rocker bridges and solved the clearance issue. I gave a pretty detailed writup in this post several pages back but at first crank over, I only had 4 cyl with compression.

I ran 220k without issue, I don't really want to get into cam replacement as my stock lifters and rockers were not worn much at all. I did inspect the lifters last night and they all look perfect. Is there anything visually I should be looking for as the failure point?

I am going to push this farther up the chain at Ford, I am lucky it didn't cost me an engine but it did cost me MANY hours of labor and I still have at least 3 dented pistons. The next guy might not be so lucky.

 

[AirFishAutomotive]

when you buy aftermarket push rods they are almost all for 6.0/6.4 , if you havent gotten them yet i would go aftermarket, with a 3/8 or something along those lines

 

[kleake]

Already ordered OEM. I would normally agree with going stronger, but I'm glad the pushrod was the weak link and not the piston.

 

[kleake]

Pedestals are within .005 of each other, not enough to make much difference when push rods are approximately .050 different.

I can't see any difference between the two rockers other than the shape of the cutout for the pivot ball. It's possible that the tip is a tiny bit longer, but you are looking at a rocker that has 220k vs 10k on it so some wear could be there. The center pivot ball location looks like it may be a tad different, but I really can't tell for sure and it's nearly impossible to measure any differences. Very possible there is .010 difference on all 3 locations creating .040 difference overall but that is a guess at best.

 

[6.0 Tech]

I never even thought of this either. I guess it explains why new short blocks come with new pish rods though. I dont think its printed anywhere in our material, at least that i have found. Good to know!

 

[kleake]

Sorry, meant to add pics earlier.

 

[kleake]

How much air is acceptable past the valves before I consider them bad? New heads bolted on, pressurize each cyl to about 110 psi, most have 0 detectable getting past the valves, but a few have just a teeny bit. Tap on a valve stem and it seals up or at least very very close. One cyl though still has what I would consider a fair amount leaking into the exhaust. I have rubber gloves on and I can put my hand over the exhaust port and make the glove whistle. Seems fairly excessive to me, but will it break in quickly? I tapped on the valve and it changed, sometimes better, but never stopped like the rest did. Bad replacement head, or am I being too picky?

 

[morefuel]

How much air is acceptable past the valves before I consider them bad? New heads bolted on, pressurize each cyl to about 110 psi, most have 0 detectable getting past the valves, but a few have just a teeny bit. Tap on a valve stem and it seals up or at least very very close. One cyl though still has what I would consider a fair amount leaking into the exhaust. I have rubber gloves on and I can put my hand over the exhaust port and make the glove whistle. Seems fairly excessive to me, but will it break in quickly? I tapped on the valve and it changed, sometimes better, but never stopped like the rest did. Bad replacement head, or am I being too picky?

Total different motor but when I took my Honda head to get checked all the intake valves were bent some. but only one cylinder was bad enough to notice any compression loss. They told me that the valve will flex just a bit and still seal but eventually the flexing can cause it to break.

 

[kleake]

I don't think this one is leaking near enough to throw of a compression test, and likely would seal under a cyl firing and/or once it wears in a little. I just found it odd that all the rest sealed completely, or had only a tiny amount of air, but yet this one is a fair amount. Being new heads, It's not as good as I would prefer, but then again, I don't build these things every day and don't know what the normal is.

 

[Wizbangdoodle]

What you're performing is a leakdown test. There are specs for how much pressure it should hold for how long. If it is leaking that much, I'd say it's a bad valve job. Those should seat from day 1.

 

[kleake]

I don't have any gauges for a specific leakdown, but I can say I am losing more pressure (probably twice as much) past the rings than I am past the valves.

 

[kleake]

I spoke with the dealer that I originally purchased the heads at. The particular rep was aware of the pushrod length change, but was unaware that it would cause clearance issues. After talking for a bit, he understands the concern, but doubts Ford will do anything about it, but he said he would turn it into his warranty department and see what they say.

I have 2 concerns:
1. Ford needs to put out some sort of notification via TSB or when you buy new rockers that informs you that you also need to buy new pushrods, ESPECIALLY if you give them your VIN. My goal here is to prevent the next person in my situation from going through this, or worse, having a more catastrophic result.

2. I would like a least some compensation for me having to backwards engineer their design change and tear into my motor a second time. Had this been handled properly up front, I wouldn't have ever had clearance issues requiring the hours I put into this, AND would have prevented me from having to tear it down a second time.

I'm just thankful I didn't end up with a broken valve or piston over this deal.

 

[kleake]

Ok, a little more info.

I talked to the dealer again that was going to turn this into their warranty department, nothing came of that, but he did give me the contact info of a couple of very reputable shops that specialize in the 6.0/6.4 Ford truck. Neither have seen this and both originally looked towards an install error or some other component way out of spec. Both agreed that the push rods only helped center the plunger in the lifter, and had nothing to do with bottoming completely. After some detailed explanation, neither could point at one thing but both agreed something is odd, which I completely agree with.

So tonight I have both new heads installed, and ran a compression check and a true leak down test (picked up some gauges today). All checked out good with the #8 cyl having a slight leak in the exhaust valve, but still only about 25% loss compared to the others at 20% so pretty close overall. Compression test is about 10psi less than the others. Likely a valve that will seal better after break in.

Now the interesting part: I put my stock push rods in to see if these heads/rockers do the same thing and they do. No, it isn't as bad because they do seal and get full pressure, but I can put 2 blue paper towels between the valve and the rocker and I start to lose pressure. Effectively the lifter is bottomed and the valve is just on the edge of sealing. 3 paper towels and i'm losing 70% of the air. I don't know what 2 blue paper towels come out to when the are compressed, but it can't be more than about .001-.004. What this tells me is that the now second set of heads and rockers have the same issue as the first set, only maybe slightly less. The only other component I did not change that was changed the first time is the lifters. This would tell me that if anyone gets away with swapping heads/rockers without changing push rods (job 1 trucks), is running with the lifters fully compressed.

I've pretty much decided everything is within range with the new shorter push rods so i'm going to start buttoning it up and see what happens.

 

[kleake]

And just to confirm the rockers are in fact what is different, I put in my original push rods with the new rockers. 2 blue paper towels between the rocker and the bridge and I start to lose a small amount of pressure. 3 paper towels and i'm losing 70%. So to verify, I switch to my factory rockers and I can put 16 paper towels in, and the rockers still wiggle and I'm not losing any pressure yet. Confirming, the rockers are in fact different, and the shorter push rods allow for the change.

I can only suspect that my engine has tighter tolerance than most, causing it to be beyond the available range once the rockers were changed where most I guess are still within range, although likely right at the end of the lifter travel.

 

[kleake]

Got her fired up Saturday night, finished buttoning everything up on Sunday and she runs great! Exhaust sounds smoother as well. This has been a HUGE pain, and dealing with Ford to help find the source of the issue has been pretty much useless. The main takeaway from this is to always change push rods when you change rockers on these. It would have solved me HOURS of work had I known that up front.

 

[michaelite]

When you change rockers or when you change heads?

 

[kleake]

Rockers... heads are the same, the change is in the rockers, calling for shorter push rods. I am sure if the heads are milled it would make it worse, but the biggest change is in the rockers. This mostly applies to the job1 trucks as the later ones already have the updated components.

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