Yeah. Set it back to SD and log fuel trims.
Should be getting misfire with a wiped lobe.
I saw a problem one time on a SBC where oil pressure dropped when a lifter was at a certain spot. Noticed it while running the oil pump with an electric drill and turning the motor over with a wrench. Block had to get bronze lifter bushings.
This post has a few applicable ideas. Didn't you mention something about a hole drilled into a galley plug?
https://www.speed-talk.com/forum/viewtopic.php?t=47909
Last edited by SiriusC1024; 07-21-2023 at 05:24 PM.
Alright back from vacation. How are you doing?
Here's something else I found:
https://www.camaros.net/threads/dril...-plugs.452329/
"I was a GM service technician back in the 70's and GM sent a bulliten out around 1970, that was the year that they revamped the Mark IV engine, stating that all of these big blocks now have the front gallery plugs drilled. The sole purpose of this, according to GM, was to bleed off the tiny air bubbles trapped in the lifters. This condition was more prominent when a higher lift cam was installed with stronger valve springs. This air being trapped in the lifters could happen to any given lifter, but was more prominent in the forward lifters due to the fact that the longer distance to the front of the engine made it harder for the lifters to bleed out. This condition usually happened after a drive, causing the oil to become thinner, stopping the engine when the front valves are in their open position. The pressure from the spring is higher due to the valve being open. While the engine is shut off, the spring pressure would put pressure on the hydraulic lifter plunger, thus collapsing it. The bonus of drilling these plugs is that you provide extra oil to the timing gear set. Most engine rebuilders have no idea of this and therefore do not drill these holes."
Good! Had a mini-vacation before my real vacation. We took a trip to VA beach for a graduation present concert for my daughter. Was fun. I put that QS Euro in and it seemed louder actually. I didn't yet drive it or even look at anything since then. I am wondering if maybe my valve adjustment process left them a little loose all around. I had read some threads that said 'wiggle the pushrods till there is no up/down movement then do a 1/2 turn'. I also read 'rotate the pushrods till they don't spin, then do 3/4 turn'. So I had done the wiggle till no up/down play, then 3/4 turn... Maybe my definition of play and the real definition of play is different? I contacted CompCams and they mentioned that, for those lifters, between 3/4 and 1-1/2 turns was good, with ideal at 1 turn... I am going to go another 1/2 turn on one side to see if it makes a difference and if it does then I will do the other side. I will also check the geometry and the roller tip where it hits the valve tip to look for wear or deformation... I was a little concerned when I drained the second batch of oil and it still had the swirl and 'glitter' in it, but read on a lot of places that the first few oil changes can do that. Nothing big in there, just a bit of sparkle at night with a flashlight. When draining the oil it looks clear, I just can see the swirl in the pan and the magnetic drain plug was basically just discolored, not the porcupine looking pattern. It was a full rebuild with new bores, rings, pistons, crank, rods, cam, cam bearings, lifters, pushrods, rockers, springs, rocker studs, timing chain, and oil pump, so I could see some normal wear/break-in occurring? No knocking, just lifter/rocker noise. I've seen the bearing slop oil recently when I took it apart and it doesn't seem like that at all. I am probably just trying to talk myself down though!
Congrats! You must be a proud dad.
I always did pushrods until I couldn't rotate by fingertips. Then lock them down 1 1/2 or so.
Have to be careful because doing it this way with a collapsed lifter will lead to bad results. I think what you're dealing with is as described above. Air ingress and high spring pressure. I'd be wary of adjusting the lifters without taking into consideration that they may already near bottom. It's a simple procedure but easy to screw up.
What do you think about the comments concerning the gallery plugs being drilled? Sounds about right, especially considering the pronounced effects with lighter grade oil. Think you need to pull the timing cover and do that? I read GM spec is a .030" hole, but I've seen a lot of people doing a .020" hole in the plug for each lifter bank located right behind the timing sprocket.
Last edited by SiriusC1024; 07-25-2023 at 09:03 PM.
Thanks! I am! So that twist feel on the pushrods is on a hydraulic lifter too? I wasn't sure about that part and did think that I may have erred on the waaaaayyyy loose side of things as I just took out what I could feel in up/down play. The rods still spun and moved around side to side, but not up/down. I.E. I could shake the rocker arm around side to side. I am not sure that the drilled plug applies to the Gen VI block as it has its own main for the cam and for the crank mains as far as oil galley is concerned? I did hear of it in the Mark IV, but not the Gen VI... I know the builder didn't seem concerned when I told him I removed it after having put it in the rear of the engine by mistake. I would also expect the small bubble bleed out to be an intermittent thing no? I am going away next week on vacation and then going away for work the week after so between the packing and prep work, I will try to get something done!
Last edited by oldpartsnrust; 07-25-2023 at 09:38 PM.
Yes, that's what to do on these hydraulic lifters. When the pushrod stops spinning by light finger pressure that means there is no gap between the pushrod and the lifter cup and rocker arm. Once that is reached THEN preload is set by turning the rocker nut a set amount. Of course, this is assuming that the lifter isn't collapsed. That's what to look out for. So, loosen the rocker arm until there is a lot of play. Give the lifter time to raise the plunger back to the top of travel. Also, I prefer to do adjustment when the lifter is riding on the base circle of the cam. This means both valves are closed on the cylinder being adjusted, somewhere between the compression and expansion strokes - intake valve closes then give a half turn on the crank. Make sure the pushrod is seated where it's supposed to be when setting preload. Don't get it off-center.
If 1 1/2 turn preload was applied to solid lifters then that would be very bad. Valves would hang open, and something would have to give eventually.
As far as air in the lifters, I too figured that the air should bleed itself out. Thing is it doesn't for some reason. GM saw fit to add the holes on Gen IV. I was under the impression that this meant Gen IV and up. Maybe there was an oiling revision on VI that means this is no longer required? I haven't seen evidence for that. Oil passages were revised in Gen V to move the lifter passage closer to the cam, but the circuit is still the same as IV. If you look at the different block versions the plug locations change slightly, but they're still there.
What stood out in the comments is that lifter collapse is made worse by higher lift cams and stronger valve springs, which is exactly your setup.
Putting in drilled plugs will remove one (likely) variable. Plus, extra lube on the timing set will help longevity. If the valvetrain noise can't be adjusted out I recommend trying it.
Last edited by SiriusC1024; 07-26-2023 at 03:33 AM.
Different manufacturers have different specs on lifter preload. Call and find out what they recommend.
LS rocker bolt is an 8mm x 1.25 = 20.32 threads per inch
1”/ 20.32 = .0492 trunnion movement per turn of the rocker retainer
.0492 applied to appropriate formula =.078 lifter preload per turn for a (1.7) rocker
.0492 applied to appropriate formula =.076 lifter preload per turn for a (1.8) rocker
Typically If the bolt rotates 1 1/4 turns after a zero lash, you would want a pushrod that is .025” shorter than stock
If the bolt rotates 1/2 turn, you would want a pushrod that is .025” longer than stock
Right, but this is a different setup than LS. It's a BBC. No rocker bolts to lock down. No trunnions. Preload is set with the rocker nuts, not by changing pushrod length.
Take a look at the parts list on Post #60.
There is an instance here where changing to different length pushrods would be warranted. Once preloaded wear pattern on the valve tip must be checked. If it's too far off center then a different length will need to be selected. It can be hard to judge the contact pattern with roller tips. Put permanent marker on the valve tip and see where it wipes away. Due to the rollers, might have to wiggle the rocker side to side while rotating the engine over a few times to get it to wipe away.
It's tedious stuff. Don't be in a hurry. Pick a good few hours where you really don't need to be doing anything else. Otherwise you'll get pretty pissed off lol.
Last edited by SiriusC1024; 07-26-2023 at 08:29 AM.
That reminds me. I used the TDC wiggle/tighten all, spin 1/4 turn, wiggle/tighten, repeat for 2 full revolutions. Then I did the preload. From first start till now, the noise has been pretty consistent as in initially I thought the lifters didn't pump up because I didn't soak them, but it never changed. The Oil is at 60 PSI cold, no matter what viscosity and then will lower to about 18-20 PSI when IATs are like 130-140 and the Gauge reads 200-210. Jumps immediately when goosed and will sit at between 40-45 at 1800-2500 RPM. The Gen VI does have a separate galley for the Main Crank Bearings AND a separate galley for the Camshaft (Called Priority Main). I also found differences in the clocking of the cam bearings. I was following what I found and noticed that I was effectively told to block off the oil hole if I used the "454" cam bearing info. Turns out that the cam bearing clocking is different on the gen VI as well. I am pretty sure if I got that wrong I wouldn't have 600-700 miles on the cam without something going south by now eah?Originally Posted by SiriusC1024
Basic formula is no different. BBC are 14 TPI. Manufacturers will usually call out the depth.
As to the tighten spin method that is a big no. Lash must be set ONLY at base circle.
Small and Big Block Chevy, and other engines using the 1-8-4-3-6-5-7-2 firing order. is it easy to understand?A more detailed explanation follows below the chart. For other engines, use the firing order that matches the engine to create a similar chart.
Intake Valve Adjustment:
with #1 cylinder Intake Valve at full valve lift …. Adjust #6 Intake Valve
with #8 cylinder Intake Valve at full valve lift …. Adjust #5 Intake Valve
with #4 cylinder Intake Valve at full valve lift …. Adjust #7 Intake Valve
with #3 cylinder Intake Valve at full valve lift …. Adjust #2 Intake Valve
with #6 cylinder Intake Valve at full valve lift …. Adjust #1 Intake Valve
with #5 cylinder Intake Valve at full valve lift …. Adjust #8 Intake Valve
with #7 cylinder Intake Valve at full valve lift …. Adjust #4 Intake Valve
with #2 cylinder Intake Valve at full valve lift …. Adjust #3 Intake Valve
Exhaust Valve Adjustment:
It is obvious that this is the same procedure and sequence as the intake valves listed above. This time, ONLY the exhaust valves are being adjusted.
with #1 cylinder Exhaust Valve at full valve lift …. Adjust #6 Exhaust Valve
with #8 cylinder Exhaust Valve at full valve lift …. Adjust #5 Exhaust Valve
with #4 cylinder Exhaust Valve at full valve lift …. Adjust #7 Exhaust Valve
with #3 cylinder Exhaust Valve at full valve lift …. Adjust #2 Exhaust Valve
with #6 cylinder Exhaust Valve at full valve lift …. Adjust #1 Exhaust Valve
with #5 cylinder Exhaust Valve at full valve lift …. Adjust #8 Exhaust Valve
with #7 cylinder Exhaust Valve at full valve lift …. Adjust #4 Exhaust Valve
with #2 cylinder Exhaust Valve at full valve lift …. Adjust #3 Exhaust Valve
In the instructions above, adjustments are being made on the “opposite” valves in the firing order, specified by the engine rotation cycle. The example shows an engine with the firing order of 1-8-4-3-6-5-7-2. It is these opposites that position the opposing valve at the correct location for adjustment. That proper location is when the lifter resides on the back side (base circle, or heel) of the cam lobe, meaning that the valve is in the fully closed position.
Please, DO NOT try to adjust both intake and exhaust valves at the same time. It is NOT accurate, and gets back to the original request of forgetting (or ignoring) what was previously known about valve adjustment procedures. Each valve is adjusted independently. That means specifically, that sixteen (16) individual adjustments will occur on a typical V8 engine.
I will give that a go as soon as I can find the time. I am going away this weekend thru next weekend and then traveling for business the following week! Sheesh.... Thanks for the info. The wiggle/tighten did get it running for me though!
Look. I get you're trying to help. That order of operations is an alternative way to get to base circle, but you're confusing the situation.
Most definitely use the spin method to find zero lash. After that apply preload.
The preload as measured in thousandths in relation to thread pitch and turns has already been figured. There is no 'if bolt turns this far after zero lash then get a different pushrod length' about it. The nut is supposed to be turned after zero lash. That's how the lifter is preloaded. Again, you're talking about LS-style trunnions or shaft-mount rockers like on a 340 Mopar. These don't work that way.
Do it on the base circle. I already said that.
Certainly, both rockers on a cylinder can be adjusted at the same time. If it's done as I described then both are on the base circle. This happens midway between compression and expansion strokes. BOTH VALVES ARE FULLY CLOSED.
There are 3 ways to make sure that the lifter is on the base circle:
1 - Turn engine over until intake valve closes. Give another half turn on the crank.
2 - Method based on firing order
3 - The best method. Use a dial indicator. Indicate on the valve spring retainer.
Follow my instructions:
- Cold engine
- Select a cylinder for adjustment
- Choose a method for getting the lifter on the base circle of the cam.
- Loosen rocker nut and let lifters relax
- Tighten rocker nut until pushrod can't be spun with finger pressure.
- Tighten rocker nut to set preload (3/4 to 1 1/2 turn. I think it was mentioned that Comp recommends 1 1/4 turn)
- Move on to the next.
Look up any procedure. It's as I described. Here's one:
https://www.speedwaymotors.com/the-t...-8-steps/28654
As far as checking valve tip contact pattern. This will only need to be done on one rocker because the geometry will be the same for the rest:
- Select a rocker and valve
- Dissassemble. Clean oil of rocker roller tip and valve tip. Apply permanent marker to valve tip.
- Reassemble.
- Set valve lash.
- Turn engine over a few times.
- Check wear pattern.
- If wear pattern is off-center then select a different length pushrod.
Last edited by SiriusC1024; 07-26-2023 at 11:10 PM.
I am back! Ugh, what fun business travel is... </sarc>
I took the valve covers off and re-adjusted the valvetrain, using my new remote start switch to speed up the engine rotation. I have almost the identical noise. I did notice that the Euro oil caused the noise to increase, so I did swap in the thicker 15W-40 Rotella which seemed to quiet it down somewhat. There was ZERO glitter in the oil this time, but it had maybe a mile on it? The assembly lube 'swirl' was also greatly decreased. Still no metal parts, chunks, slivers, etc. I did notice that if I took the rockers and wiggled them I seemed to be able to recreate the valve noise. Maybe I am hearing the roller tips slapping back and forth or the pushrods gliding on the guides? I will take it apart again tomorrow to see what I can find along the lines of the pushrod guides, the rocker tip geometry or something. I plan to re-run tune 8 now that I have the IATs somewhat reduced to see if you notice any difference? Thanks again for all the help.
Yessir bring it on.
Here are a couple of driving around town logs... after hot soak, the IATs were up, but did seem to come down a bit after driving, but still showed red. I didn't hit the highway or anything so it didn't have a chance to get a lot of cool air. I was thinking of putting in some 102+ octane boost or something to see if we can determine if the knock is real or if it is the valve train noise?
Try the octane booster. There's actually more knock sensor activity than ever.
Did you ever try a quick swap to the factory rockers?
I don't think I had the Knock Sensor logging on last time I ran the #8 tune, but I could be mistaken. Anyway, I got the booster and will get it in tonight and hope to run around a bit tomorrow for some more logs. I like the "quick swap to factory rockers"
The valvetrain noise is a real pain isn't it? So many things it could be. It's probably something to do with the lifters if it gets quieter with thicker oil. Lifter noise from lash/preload is ruled out after you readjusted. I still think that putting drilled galley plugs in would work be the solution. Suggested rockers because that would handle the pushrod contact on the guides.
Loud exhaust won't affect the knock sensors.
Difference in tune between 8 and when you were logging wouldn't affect the knock activity like that. Spark hasn't been advanced.
If I tune the knock out by desensitizing the sensors then there's no guarantee real knock will be detected.
I probably didn't say what I meant correctly. The tune 8 that I ran logs on the first time didn't have the knock enabled. I went back and looked and it came into play with tune 9. I ran that one both without the KR and then again with the KR. I was hoping that I didn't overdo it with the compression. There was a lot of inconsistent information on calculating the actual compression ratio. I was shooting for 9:1 - 9.5:1 but may have overshot. I do feel it is pretty high due to the herculean effort to crank over by hand! If I need to run high octane with some octane boost, so be it. This is just my tow vehicle a couple times a year and as long as it can tow RELIABLY I am happy! IF the contact pattern looks good without needing adjustable pushrod guides or different length pushrods then I will give the stock rockers a go. IF THAT quiets it down, then I will swap back and run it. I don't mind the noise, I just want to make sure it isn't a symptom of impending engine failure. I want to make sure I am not researching to corroborate the least serious diagnosis and then have that be wrong!
Last edited by oldpartsnrust; 08-14-2023 at 09:32 PM.
Let's see how it does with the octane booster.
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