Quote from: Kevin66 on August 20, 2025, 07:57:52 PM

Quote from: blykins on August 20, 2025, 04:53:46 AM

I didn't even see the pics first time around. 

Cory is right, #7 and #8 poly lock set screws are not in the same location as all the others.  That should be an indicator of something...

The rocker arms have the typical Chinese font on them.  It could be that they're just cheap rockers and can't handle the setup.

Brent thanks for chiming in here. As you and Cory noted, there are differences between the #7 & #8 polylock set screw and the others. During the Re & Re of the valve springs from the original FT ones to the lightweight checking ones, a rocker stud bent using one of those over-centering, screw-on spring compressors. The replacements I received were not the same as the original Flo Tek ones. I think they were 1.895" effective length Vs the 1.75" of the rest. It seemed like the relative position of the Allen-head lock screw was the only thing affected, so they were used.

Oh, I meant to ask you...in your first post you mentioned "pushrod hitting the rocker" as one possibility to look out for. What did you mean by that? I'm having trouble visualizing it.

You're getting less lift at the valve because of valvetrain deflection.  My habit is to always measure lobe lift, so that you know the cam is ground correctly.  I do it as part of the degreeing process.  Then when you know that, you do whatever you can to eliminate any valve lift loss.

On some combinations, at full lift, the pushrod will hit the back of the rocker arm.  Probably won't happen on a 1.6 rocker, but you can run into it on a 1.7. 

On your valve setting procedure, use the EVO/IVC method.

Thanks again everyone, for all the information and guidance. I have a height mic now and will begin checking all the installation clearances this evening.

As for the EO/IC valve adjustment procedure, I have a question for those of you who use it. I've seen it written, and heard a couple people mention, that they just rotate the engine a little past the actual opening and closing points (whichever is relevant to the valve you're working on), then do the adjustment. However I've also seen it mentioned (I'm including pics of two) where they say to go way past the maximum lift point with the intake closing and then make the adjustment on the exhaust valve. What do you all use/recommend?

If you drove it 18 miles without an issue, and then after sitting for a bit and starting it up again it developed a problem immediately, I would look at valve guide clearances.  Especially if only exhaust rockers or pushrods.  JMO, but look at that, also.  What is that white substance in the intake ports?  Thread sealer for the studs?  Make sure you remove that before installing the intake next time.   Joe-JDC

Thanks Joe. I had considered that, but then dismissed it, feeling that it wasn't likely a guide could grab a valve tight enough to break a rocker arm in pieces? But I do note your suggestion about looking at the exhaust side first.

As for the thread sealer, yes that's what it is. But this photo was from during engine assembly and setup, and it was removed prior to intake installation and startup.

Incidentally, that is one NICE intake manifold you did up! Obviously with the problems we've had, and the sub-3,200 RPM speeds so far, we haven't been able to give it a good run, but are certainly looking forward to doing so.

I recently assembled a new engine for my brother's '66 Comet. ALL parts were new.
   - Ford Racing M-6009-363  363 cid crated shortblock, 4.125" X 3.40", with Mahle forged flat top pistons with generous valve reliefs
   - Flo Tek 185cc 'Thumper' CNC ported aluminum heads w/ 2.02"/1.6" s.s. valves (rated flow = 278 cfm Int & 182 cfm Exh @ .600" lift)
   - Ford Racing M-6051-R351 head gaskets and M-6014-BOSS ARP head studs
   - Lunati Voodoo VDSF-282 hydraulic roller cam (231°/239° @ .050", .581"/.587" lift, 110° LSA); Rollmaster billet roller timing set; Installed @ 109.5° Int C/L
   - Edelbrock Performer RPM Air Gap intake manifold (professionally ported by Joe Crane)
   - Quick Fuel 650 cfm SS-series carburetor
   - Jegs #20990 1.6 ratio 3/8" stud aluminum roller rockers; Jegs #20277 6.248" pushrods
   - Boss 302 6-quart oil pan & 5/8" tube pickup, Melling Hi-Volume oil pump, ARP drive shaft, Comp 10W-30 Break-In oil
   - Patriot 'Clipster' shorty headers
   - Pertronix billet electronic distributor, Ford Racing 8.2mm wires, Autolite AR3932 spark plugs gapped at .035"

The engine was carefully assembled, with everything torqued to specs, and the cam degreed per Lunati's specs. The cylinder heads had been originally set-up by the factory for flat tappet use, so the springs, retainers and keepers were replaced with Trick Flow PAC dual springs (16315-16), Chromoly steel retainers (51400423) and hardened keepers (51400444) for use with the HR cam. The adjustable guide plates were maneuvered to get the rocker roller tips aligned on the valve stems.

When installed and fired, the engine started instantly and ran well. Pressures, temperature and leaks were checked. The initial timing was set at 16° BTC. The car was then taken for a drive of about 18 miles, and there were no issues with the engine's operation. RPMs were kept below 3,000. The exhaust had been cobbled together with 2.5" stubs, 20° & 45° bends to mate up with the previous dual exhaust system until the car could get booked into a muffler shop for a complete new exhaust system. There were leaks from the ball & socket collector flanges, so the head pipes were removed and re-positioned. NOTHING else was changed.

On the next run, there was only a minor leak from the passenger side exhaust, so another drive was attempted. Within half a mile there was a loud backfire, and the engine began running poorly. It did not want to rev-up, and had little power. It backfired several more times.

On examination, we found that the #7 exhaust rocker arm had broken in two down around the trunnion, with the polylock nut seized in its slot. The pushrod was bent. Any is not good, but it wasn't excessive. We checked the other rockers and all appeared to be still adjusted properly, except for the #2 exhaust rocker, which now had a slight amount of valve lash. We couldn't see anything amiss, so it was readjusted to zero lash plus one turn. A compression test was done, with all cylinders falling between 152-162 psi, so there were apparently no bent valves. The engine started fine, and again the car was taken out on the road...only to return within two minutes, farting and popping. This time, that #2 exhaust rocker arm was broken.

All of the rocker arms, pushrods and studs were then removed. What we found was that the ball on the lifter end of that #2 exhaust pushrod had broken off, and the end of the pushrod was badly mushroomed. Four of the other pushrods were now bent. Four of the other rocker arms had trunnions that would only rotate with a good effort, not freely as they should have.

The intake manifold was removed to attempt to locate the missing pushrod ball, and it was found sitting in the valley beside the lifter boss. And it was now found that the #7 exhaust lifter had a chip out of the upper rim, and that the snap ring had popped up from its groove, but luckily not gone anywhere. At this point we stopped work, unable to explain what was happening, and why?? The engine had been rotated dozens of times by hand for valve adjustment prior to startup. There was no interference that could be felt then, so what had changed?

If you've gotten this far, you know that I'm perplexed and frustrated. I could really use some help from those of you with engine building experience. What did I miss? What should I check?

Thanks for your time!



 

It's a shame they didn't opt to do something about the rocker shaft stand pad height, or at least make Ford spec ones a factory option!

Just some thoughts for you to consider. Are you absolutely certain that your crankshaft is an actual 3.98" stroke 410/428 one, and not a 3.78" 390/406/427LR one? The reason I ask is because I have seen issues where people have installed replacement 410 pistons (with a 1.66" compression height) into 390 engines (which want a 1.76" compression height). This results in the engine having the .025"-.035" deck height you describe, which substantially lowers the compression ratio, down into the 8.X:1 range. That has a LARGE detrimental effect on the engine's power output.

I believe your estimation of both your static and dynamic compression ratios is off considerably, and it needs to be brought up. To achieve that, I really don't think you want to be cutting .030"+ off the deck surfaces! Unless you can find some actual high compression 420 pistons in .030" O/S, you may need to look at custom ones.

I agree completely with Brent Lykins' comment about the camshaft, if you do want horsepower up in the 425-450 range. He knows a lot more about cams than I do, but I suspect would advise going up about 10° @ .050" on both intake and exhaust. What you have now is essentially just a 'very mild' improvement on the stock 428CJ cam. These motors made about 400 HP from the factory, and that's with the CJ heads, 10.6:1 c.r., a very good factory intake and 735cfm Holley carb. It also had much better exhaust manifolds than your truck came with. So as several others have suggested here, get some actual headers for your truck. In that regard, Jay Brown found in his testing for his 'Great FE Intake Comparo' book, that an engine in the power range you're talking about (425 HP 428CJ) would 'average' about 330-336 HP with several different headers, and the ancient 'log' style exhaust manifolds, as found on most factory FE's, would only muster 293-296 HP.

And definitely replace that 83 Lb. cast iron intake manifold! Almost any aftermarket aluminum 4-Bbl intake you can find will deliver more power (as much as 35 HP!), and will take 50 Lbs off the front of your truck!

Sorry, I meant to include this one too.

Brent I can't say for sure. I suspect these beehive springs Blair installed wouldn't be stiffer than something like the Comp 26120...155# closed, 377# open...and likely less?
But I'd also say again that half of the valves weren't being opened at all (driver's side head), and only the four intake valves on the passenger side were adjusted right, so as to get maximum lift.
And yes, I was using a 2' breaker bar with a 1/2" drive socket on the ARP dampener bolt.

Building a 455 cid FE stroker motor (4.13" X 4.25").
- New Eagle crank and 6.7" rods
- New DSS forged pistons
- New Hastings ductile moly file-fit rings
- New Federal Mogul HD rod & main bearings
- New Cloyes Race Billet timing chain & gears
- New Bullet HR cam (250°/258° @ .050", .562"/.597" lift, 112° LSA
- New Crower EnduraMax roller lifters, new Smith Bros pushrods, Comp roller rockers/shafts/stands w/ end supports
- New Melling HV oil pump & ARP driveshaft
- New Canton 7.5 quart oil pan, pickup & windage tray
- Blair Patrick CNC'd BBM heads
- New Blue Thunder MR 4-Bbl intake
- Cometic .051" MLS head gaskets (4.155" bore)

C6ME- block had been .020" O/S previously and wouldn't clean-up at .040" in a few cylinders, so a decision was made to sleeve all eight of them. To save original cylinder wall strength, the thin Melling .0625" sleeves were used, and honed to stock 4.13" bore size. Block was align honed and decked to true. Crank & rods were checked, and entire rotating assembly was balanced. Rings were file-fitted to .018". Pistons were miked and assigned to bores. They protrude about .010" above the block deck, hence the thicker than normal head gaskets.

On assembly, using Permatex assembly lube, the crank rotated freely, although it would not 'spin' after giving it a push. I blamed this on .0015"-.002" main clearance and the drag from the lube. Pistons and rods were installed without incident, and the assembly could be rotated smoothly, with some drag. Engine was rotated numerous times by hand, and although resistance was higher than expected, nothing really caught my attention.

When the cam was installed, two things drew my attention. The first was an audible 'clunk' sound, and the rotating assembly locked-up, although it would turn backwards easily enough. It appeared that, at least on some cylinders, the rods were hitting the cam lobes. The shortblock was disassembled, and the rods were machined for the necessary clearance. Everything went back in, and as expected, nothing now stopped complete rotation of the engine.

However, an error was quickly discovered when I set out to degree the camshaft. Despite the timing marks on the gears being aligned as they should be, opening and closing points were WAY off what they should have been. Sure that Bullet wouldn't have made such a dramatic error, I looked elsewhere and quickly found the problem. It seemed that the dowel pin hole on the Cloyes cam gear was 180° off! Instead of the dowel pin being at 12 o'clock, it was pointed down at 6 o'clock. More trouble than it was worth to return the defective one and hope the next one was right, I simply put a new timing mark directly across on the other side of the gear, and tried that. Sure enough, now the degree wheel indicated that the Bullet cam was dead on the money, installing at the 107° point they wanted.

The heads were installed, along with the intake. Then began the process of setting-up and adjusting the valve train. A pair of Mr. Lykins' laser-cut .050" shims had been found to center the roller rocker marks on the valve tips, so it just remained to set the valve lash. The spark plugs were out to allow engine rotation, and only the passenger side shaft assemblies were in place. With the rocker adjusting screws backed off as much as possible, I went through the process of setting the intake valves on cylinders #1 - #4, using the EO-IC procedure. With those done, I set out to do the exhaust lash adjustment...whereupon I ran into the problem!

As I was bringing #4 around to intake closing, the engine more or less locked up, and would no longer rotate. Attempts to reverse direction were met with the same condition. Since the engine had now been rotated dozens of times, what could be causing this? Resorting to trying a 2' breaker bar, with a little more grunt applied, I found that the dampener bolt...previously torqued to 100 lbs/ft...was tightening up more, rather than the engine rotating! I again tried to reverse rotation, but the engine wouldn't budge.

Trying to think through this, I couldn't come up with anything logical. There had been no 'clunk' as I got when the rod/cam lobe issue came up, and I had neither heard any scraping noise nor felt any 'gradual' increase in resistance, it had just stopped. I finally resigned myself that there was nothing else to be done except to dismantle the engine, checking carefully for something wrong. So off came the rocker arms and pushrods, looking first to make sure there was no coil bind or other issues with clearances there. Next came the intake and the heads. Not finding anything to indicate problems...no witness marks on pistons or valves, and nothing else that seemed abnormal, I prepared to remove the oil pan, oil pump and windage tray so I could look at the bottom end.

Before doing that, it occurred to me to take one more stab at engine rotation, with all these parts removed now. Once again, I could not turn the motor clockwise, but on trying it counter-clockwise, it resisted for a second, and then turned. I continued in that direction, rotating the crank 90° each time. I went through three complete rotations, stopping with #1 at TDC. Then I changed to clockwise rotation, and turned the engine through four complete rotations. It seemed like the problem had gone away!?

Sorry this has been long-winded, but I wanted to give everyone the facts as they happened, before asking:

- What the heck went on here?
- What was likely causing the problem?
- What would YOU do next, if it was your problem?

Hopefully, with all the decades of experience and expertise on this forum, someone has an idea and can give me a clue. Thanks for your time!