XER Lobed Cams Eating Lifters?
09-27-2012, 08:33 PM
#21
no.. and no....
more pressure = more control...(especially with an XER lobe)..
there is a point where pressures become so great that you have to start thinking about other parts... but he is a long way from that.. the valve spprings he has are an excellent choice for that cam
and a single spring is always a bad idea when you can go with a double and have a 2nd chance at saving the valve from dropping if one fails, and potentially have enough time to shut it down before the valve puts a hole in the piston because of falling...
and again XER Lobes... Double spring is a must
more pressure = more control...(especially with an XER lobe)..
there is a point where pressures become so great that you have to start thinking about other parts... but he is a long way from that.. the valve spprings he has are an excellent choice for that cam
and a single spring is always a bad idea when you can go with a double and have a 2nd chance at saving the valve from dropping if one fails, and potentially have enough time to shut it down before the valve puts a hole in the piston because of falling...
and again XER Lobes... Double spring is a must
09-27-2012, 08:46 PM
#22
When I called Manton I was looking for a pushrod to use for mock-up. Terry called me back within minutes from his car. He made me one pushrod with a removable end so I could cut the length for mock-up. Shipping was more than the pushrod and he made it for me within a day. I agree, they are very customer oriented and their prices are very reasonable for the product they provide.
09-28-2012, 09:19 AM
#23
So must have been right at max preload or very very close. If past preload, the valves would never close and the engine would not run at all. Unless just a few were that close. Still would run very poorly.
I mentioned coil bind because Vettenuts said stock heads end up less than 1.8" installed height w/o shims.
So Dirtbag, good find...sorry about the process for you. Should add this as a sticky for the need to always check pr length. In fact, I tink this section needs a sub section on pushrod length as often as the question seems to be asked.
Ron
09-28-2012, 01:24 PM
#25
Scott, my bad. I completely missed the part where he said he had too long of pushrods......what happens while reading posts during boring work meetings.
So must have been right at max preload or very very close. If past preload, the valves would never close and the engine would not run at all. Unless just a few were that close. Still would run very poorly.
I mentioned coil bind because Vettenuts said stock heads end up less than 1.8" installed height w/o shims.
So Dirtbag, good find...sorry about the process for you. Should add this as a sticky for the need to always check pr length. In fact, I tink this section needs a sub section on pushrod length as often as the question seems to be asked.
Ron
So must have been right at max preload or very very close. If past preload, the valves would never close and the engine would not run at all. Unless just a few were that close. Still would run very poorly.
I mentioned coil bind because Vettenuts said stock heads end up less than 1.8" installed height w/o shims.
So Dirtbag, good find...sorry about the process for you. Should add this as a sticky for the need to always check pr length. In fact, I tink this section needs a sub section on pushrod length as often as the question seems to be asked.
Ron
Here is a picture of what happened to the last failed lifter. This time I hope the damage is not as bad.
10-06-2012, 11:56 PM
#26
Finally an overdue update -
http://youtu.be/xIGujiGq4kY
The video speaks a thousand words. Making the video I had no idea the damage would be this extensive. Not only will the cam need to be replaced, the oil pan have to be dropped to retrieve the chunks of lifter, oil pump needs to be replaced since the current one is most likely loaded with metal fragments, bearings will have to be inspected for damage, and somehow I have to clean out the oil galleys to rid any metal fragments. We are talking a major ordeal to get back to 100%. I'm toying with the idea of pulling the motor and assembling everything on a stand.
Since I've done this before it takes 50+ hours to do this by yourself without pulling the motor. Besides pulling the motor, everything would go relatively quick on a engine stand (I would guess, haven't done this before). Not to mention dropping the pan is basically impossible solo.
On the bright side - good thing I killed the motor as soon as I heard something was wrong it could have been much worse I suspect.
http://youtu.be/xIGujiGq4kY
The video speaks a thousand words. Making the video I had no idea the damage would be this extensive. Not only will the cam need to be replaced, the oil pan have to be dropped to retrieve the chunks of lifter, oil pump needs to be replaced since the current one is most likely loaded with metal fragments, bearings will have to be inspected for damage, and somehow I have to clean out the oil galleys to rid any metal fragments. We are talking a major ordeal to get back to 100%. I'm toying with the idea of pulling the motor and assembling everything on a stand.
Since I've done this before it takes 50+ hours to do this by yourself without pulling the motor. Besides pulling the motor, everything would go relatively quick on a engine stand (I would guess, haven't done this before). Not to mention dropping the pan is basically impossible solo.
On the bright side - good thing I killed the motor as soon as I heard something was wrong it could have been much worse I suspect.
Last edited by dirtbag; 10-07-2012 at 12:21 AM.
10-07-2012, 09:46 PM
#27
Couple of thoughts to throw into the mix. Not sure on your installed height, but the stock heads I have worked with usually set up with an installed height less than 1.800" so your seat value "may" be north of 145 lb. Your open spring force with that lift cam may be approximately 425 lb. Your pushrods may be flexing quite a bit and hammering the lifters due to these higher spring force values. (Every part in the valve train flexes but the pushrods can act as pole vaults with too much force and no increase in stiffness).
Don't overlook pushrod diameter as well as length as OD is the only real way to increase the stiffness of the pushrods. You may want to consider the Manton 11/32" pushrods when you sort this out as a replacement since they will usually fit stock heads. If the heads come off you could also open the pushrod holes for 3/8" OD pushrods.
Don't overlook pushrod diameter as well as length as OD is the only real way to increase the stiffness of the pushrods. You may want to consider the Manton 11/32" pushrods when you sort this out as a replacement since they will usually fit stock heads. If the heads come off you could also open the pushrod holes for 3/8" OD pushrods.
1. According to some other threads, stock rockers can only handle around 400-410lb of pressure or the rocker tip will deflect off center on the valve stem resulting in eating the valve stem tip or other issues like prematurely wearing the valve guide.
2. If the install height is less than 1.800", closed and open spring pressures could be as high as 425lb open or 155lb closed. According to comp cams, too high of closed spring pressure can prematurely bleed out lifters and lead to collapsing and thus lifter failure.
3. Assuming a restriction of 410lb spring pressure, a 0.565" lift cam at 1.800" install height is a perfect match for these springs. In my case, The 224R cam is too big for stock rocker use with this spring set.
I ran a simulation with my valve train mass on valve and cam side with the 224R cam, and found my optimal spring pressure to be 385lb of open spring pressure. I need a spring with coil bind at 1.159" ( with a 0.060" safety net for lift amount). The LS7 lifters will be quieter and give overall longer valve train life with a lower closed spring pressure.
Last edited by dirtbag; 10-08-2012 at 12:40 PM.
10-07-2012, 10:27 PM
#30
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I have a 224r cam XEr Lobes .581 lift w/ 114LSA and 7.4" TSP pushrods. I use .650 lift patriot gold valve springs. No issues, along with 799 heads and LS6 head gaskets.
10-08-2012, 12:31 PM
#31
The plan is to switch to valve springs that achieve around 400lb of open spring pressure at max lift of whichever grind I decide to go with. Much of this is still up in the air. Trying to decide on a combo that will be reliable and still put out a ton of power with out requiring different lifters or roller rockers.
While preload was an issue, the spring pressure also was an issue. I had an extra .079" of room before the spring would bind with the current pushrods so while the lifters were more or less turned into solid lifters, I still had some wiggle room and extremely high seat pressures.
Just plainly a poor matched combo we live and learn from our mistakes.
