John, I am trying to understand your formula. IF you start with a fully collapsed lifter how can you subtract another .085" for piston travel? Shouldn't the travel be added to give a cup height of .560"?
I am confused it seems.
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| Drool tube Hydraulic Head Question https://slantsix.org/forum/viewtopic.php?t=55770 |
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| Author: | ryandcovalt [ Fri Jul 11, 2014 6:10 pm ] |
| Post subject: | Drool tube Hydraulic Head Question |
Hello everyone, I just put a drool tube style head on my 1985 dodge ram hydraulic engine. For those of you that are familiar, the head was taken off of the engine that was on slantkota it was the stroker engine known as "eileen" From what I was told the head was only cleaned up it wasn't cut to raise compression. It had .006 removed to true it up. I installed this head on my stock hydraulic engine block using the original lifters, push rods, rocker arms etc from the hydraulic engine and I put them on the drool tube head. The problem is i tightened everything up and I do not have compression. I then loosened the rocker arm shaft bolts about 3 turns and the engine starts right up. I now assume I need shorter push rods but why would that be the case if the head was not cut? I guess it is possible the head was planed more than Brennan had originally thought? I guess I should've measured the head first, I just thought it was not cut so I would not have any problems. Is there anything else that I could be missing? What is the best way to figure out how much shorter the push rods should be? Any help or ideas would be greatly appreciated. Thanks guys, |
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| Author: | Charrlie_S [ Sat Jul 12, 2014 3:43 am ] |
| Post subject: | |
Ryan, Are you sure the pushrods are too long? It is possible the lifters are full of oil and have not blead down. You would be supprised how long it can take a good lifter to bleed down. What I would do, is loosen the valve train, pick a pushrod that has "slack". Mark the pushrod, tighten the valve train, and see how far that mark has moved. If it has not moved at least .060 I would say the lifters are "pumped up". If that is the case, the easiest way to correct the problem would be to tighten the valve train, and let the engine sit for a couple of hours, then rotate the engine, by hand, to a different position, and let it sit again. Keep repeating this untill all the lifters have had a chance to sit with spring pressure on them. |
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| Author: | Sam Powell [ Sat Jul 12, 2014 5:01 am ] |
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They sell spacer kits for the rocker arm shaft. I know you must be careful about this, or you can crack theh shaft seat, but I ran them under the shafts on my 360. I think the V-8 shafts are the same diameter. Sam |
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| Author: | Charrlie_S [ Sat Jul 12, 2014 5:41 am ] |
| Post subject: | |
Yes, the V-8 shafts and slant shafts are the same diameter. |
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| Author: | Rick Covalt [ Sat Jul 12, 2014 8:11 am ] |
| Post subject: | |
Did what you said Charlie and the push rod only moved a couple thousands. He has began the process you said about doing. |
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| Author: | DadTruck [ Sat Jul 12, 2014 10:45 am ] |
| Post subject: | |
Quote: If it has not moved at least .060
that is about right, the stock lifters from the 83 D150 had .180 of piston travel and the OE preload was .080 to .090with a reground cam, and approx .058 off the head & block combined, using the stock pushrods have a lifter preload of .070 to .080 if the preload is only .006 and the lifter is not froze, there is a stack up issue. have you compared the working lengths of a hyd vs mechanical lifter? from the face that rides on the cam to the push rod seat, along with nominal mechanical push rod length vs a hydraulic push rod. |
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| Author: | Rick Covalt [ Sat Jul 12, 2014 1:27 pm ] |
| Post subject: | |
No the lifters are not froze. The truck ran when they pulled it in the shop Friday. Ryan put the other head on and the hydralic rockers and shaft...etc. He never touched the lifters. Bolted it on and it is holding all the valves open. I never thought about the lifters holding the valves open or how long it takes them to bleed down. Rick |
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| Author: | DadTruck [ Sat Jul 12, 2014 4:25 pm ] |
| Post subject: | |
got a solid lifter and a hydraulic side by side on the bench measuring using a push rod and razor blade to put a scratch in the push rod to mark depth the solid lifter seats the push rod into a pocket .510 deep the hydraulic lifter with the lifter fully colapsed, has the seat .475 deep that particular hydraulic lifter has a piston travel of .170 if it was set to a nominal preload at half of the available piston travel of .085 the "in use" the hydraulic lifter push rod seat would be at .475 - .085 = .390 there is an approximate diffference of .120 (.510-.390) in the lifter seat depths. Don't know if this helps or not, but it was an interesting little study.. |
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| Author: | ryandcovalt [ Sat Jul 12, 2014 5:21 pm ] |
| Post subject: | |
I have been slowly turning the engine over all day. I just bumped the starter for a second to see if there was any difference and there is still no compression. When you say it may take a very long time for them to bleed down are we talking a few hours or overnight? We did some measuring and it doesn't seem like the head is cut enough to make a difference. I am still thinking it is a lifter issue not a pushrod length issue. Dad has a new set of lifters he said I can use but I would like to keep the original ones if possible. I guess I will just check in the morning and hope the spring pressure forces some oil out. I have always had issues with lifters collapsing but never with them being pumped up. I guess you learn new things every day. That was an interesting lifter study. From the sounds of it I should have plenty of lifter travel available unless the head was cut a lot, which from our measuring it doesn't seem to be. Hopefully letting it sit overnight will fix the problem if not i guess I will try another set of lifters. I did drive the truck into the shop with these lifters so I'd think they are ok. Guess time will tell. Thanks for the continued help guys. |
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| Author: | Sam Powell [ Sat Jul 12, 2014 5:32 pm ] |
| Post subject: | |
If it started with rocker bolts loose, a set of shims should fix it. Sam |
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| Author: | Reed [ Sat Jul 12, 2014 5:33 pm ] |
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Is it possible that the lifters got installed upside down? Is it possible to pull a lifter and physically examine it? The lifters can be disassembled and you can see if they are stuck "pumped up." |
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| Author: | Rick Covalt [ Sat Jul 12, 2014 5:46 pm ] |
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The lifters were not removed at all. So they are just as he drove it in the garage. Sam, where are these shims found? All I have seen were home made and I know many people split the rocker towers using them. I measured a known uncut head and this one was very close to that one, which is what Ryan expected. The head he is using was the one that was on the Slantkota. Again, how long does it take for the pressure to bleed off if they are pumped up? Is there any way to bleed them down? other than what Charlie said? It is a drool tube head so they can be removed if we need too. Rick |
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| Author: | DadTruck [ Sat Jul 12, 2014 6:14 pm ] |
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Quote: pressure to bleed off if they are pumped up?
lifters getting pumped up and sticking is something you hear about from time to time,, but think about it,to maintain zero lash, lifters need to maintain pressure ( at engine operating pressure 10 to 90 psi) bleed off and re fill hundreds of times per minute at engine rpm's. The ability for a hydraulic lifter to do that at really high RPM's ( 6K +) is where it gets tough from a design standpoint. so a lifter setting static should bled off immediately,, seing how you have multiple lifters holding the valves open,, something is wrong,, but I doubt that it is 12 lifters that magically stuck with a different head, as they were operating normally previously. I would pull the head and cc the chambers to see if the head was cut enough to put the lifter pistons out of normal travel position. |
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| Author: | Rick Covalt [ Sat Jul 12, 2014 7:00 pm ] |
| Post subject: | |
Quote: so a lifter setting static should bled off immediately
John, I am not arguing here by any means, but how can that be correct if what Charlie is saying about needing pressure on them for an hour or so to bleed them down? Just trying to understand. Thanks, Rick |
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| Author: | slantzilla [ Sat Jul 12, 2014 7:14 pm ] |
| Post subject: | |
John, I am trying to understand your formula. IF you start with a fully collapsed lifter how can you subtract another .085" for piston travel? Shouldn't the travel be added to give a cup height of .560"? I am confused it seems.
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