Need advice with lifter selection
#1
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Car: 89 IROC
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Axle/Gears: 9" Moser 3.50 True trac
Need advice with lifter selection
Ok I have had some problems with rocker arm/pushrod galling which in turn busts the lifter cup. Same thing happened to the same valve twice.
Here's the thread if you want to check it out;
https://www.thirdgen.org/forums/tech...k-problem.html
I'm currently running Comp short travel race lifters in my 414 daily driver. When everything is good the rockers have oil dribbling out the oil holes evenly. One suspicion is that there is not enough oil going to the rockers. So, I am going to either replace the damaged Comp lifter or just replace the entire set of lifters with stock/LS7 type lifters. My block will accept either and I have the dog bones and spider. The cost of both is about $50 more for the LS7 type vs replacing one Comp pair.
Should I stay with the Comp short travel race lifter or just go with the LS7's? Honestly, the engine peaks at 6k and that's where I shift. I don't know if I "need" the short travel but it seemed like a good idea when I built the engine. I just want a lifter/valvetrain that will last more than 20k before needing attention. I DO NOT feel there is a problem with the Comp lifters, just that they don't oil the rockers as much as stock one's do.
Here's the thread if you want to check it out;
https://www.thirdgen.org/forums/tech...k-problem.html
I'm currently running Comp short travel race lifters in my 414 daily driver. When everything is good the rockers have oil dribbling out the oil holes evenly. One suspicion is that there is not enough oil going to the rockers. So, I am going to either replace the damaged Comp lifter or just replace the entire set of lifters with stock/LS7 type lifters. My block will accept either and I have the dog bones and spider. The cost of both is about $50 more for the LS7 type vs replacing one Comp pair.
Should I stay with the Comp short travel race lifter or just go with the LS7's? Honestly, the engine peaks at 6k and that's where I shift. I don't know if I "need" the short travel but it seemed like a good idea when I built the engine. I just want a lifter/valvetrain that will last more than 20k before needing attention. I DO NOT feel there is a problem with the Comp lifters, just that they don't oil the rockers as much as stock one's do.
Last edited by antman89iroc; 10-24-2016 at 05:53 PM.
#3
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Car: 89 IROC
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Re: Need advice with lifter selection
Now how do I determine what "LS7" lifter are? Not being difficult but a lot of lifters are tagged as such when really any lifter from 87+ could be considered LS7. GMPP 12499225 seem to be the GM part number but if you cross it to say Comp cam its just their performance lifter. I'd like to stay with a recognized MFG & PN.
Lastly, My cam was ground with QXI QXX lobes which are fairly aggressive. 282/229 and 285/237 (from memory) and each have ~.375 lobe lift. There's no chance of the stock type lifter with shrouded rollers hitting the lobes is there? One of the features I really liked about the Comp short travel lifter is the larger, exposed roller wheel. Just checking on this one.
#5
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Car: 89 IROC
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Re: Need advice with lifter selection
Thanks for the advice. I spoke with Comp again today. They can't find any reason the short travel lifter shouldn't work. I was incorrect about the restricted oiling, they said they are normal valves. Regardless, I can't get the "doing the same thing expecting a different result" idea out of my head. Although there shouldn't be a problem with the race lifters it seems it would be a good idea to try a different type. If you guys have had success with the 12499225 lifters then it may be a good idea to try them. At least if I do have a problem in the future I can replace a single lifter and they're a lot less expensive. Seems a shame though...
#6
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Re: Need advice with lifter selection
If you are going with the LS7's, I have a full set of unused ones I got for my 383 build still currently underway. After more rersearch, I wound up going with the Comp Race lifters... PM sent.
#7
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Re: Need advice with lifter selection
How much engagement is necessary between the lifter and dog bone?
I ask because I have a stock set I mocked up in my motor tonight. I have a .950 base circle cam and the ones I tried only stick up about .150 above the lifter bores. By the time you consider the bevel on the top of the lifter and the recess on top and bottom of the dog bone retainer that only leaves about .080 engagement between them. Is this enough? I have read there are special lifters that are a little taller than stock for this reason. Anyone?
BTW the Comp short travel are available with a tool steel pushrod cup (XD version) which I wish I had gone that route now. The pushrod cup is what is getting beat out of the lifters I have had fail. I know it is probably caused by the pushrod galling but that may be caused by oiling. I don't know if these are the best choice for street use.
Last edited by antman89iroc; 10-25-2016 at 07:45 PM.
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#8
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Re: Need advice with lifter selection
I've been running Comp's short travel lifters for thousands of street driven miles and hundreds of 6500 RPM red line passes. Three different cams, two engine blocks, and still as far as I can tell (and the top end was just apart, cleaned and inspected), they look to be in fine shape.
#9
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Car: 89 IROC
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Transmission: TKO 600
Axle/Gears: 9" Moser 3.50 True trac
Re: Need advice with lifter selection
I've been running Comp's short travel lifters for thousands of street driven miles and hundreds of 6500 RPM red line passes. Three different cams, two engine blocks, and still as far as I can tell (and the top end was just apart, cleaned and inspected), they look to be in fine shape.
I am in no way bashing the Comp product. In fact, due to my small base circle cam the OEM style won't work. There are longer versions for this reason but I am going to just replace the Comp pair with the problem and give it another go. It seems the origin is an oiling problem and I am going to go back through everything to make sure there isn't anything binding. Comp also suggested running a zinc additive and I may try that also.
#10
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Re: Need advice with lifter selection
No XD. Just their 15853. They were new to the market when I purchased them (2012 IIRC).
One suggestion regarding the oiling. Perhaps you could prime the engine and watch for oil flow out of the lifter cup. You've mentioned seeing it dribble out of the pushrod. You could rotate the engine through 90 degree segments and observe the flow at the suspect lifter bore. It may reveal nothing but then again, it may uncover something relevant to your problem.
One suggestion regarding the oiling. Perhaps you could prime the engine and watch for oil flow out of the lifter cup. You've mentioned seeing it dribble out of the pushrod. You could rotate the engine through 90 degree segments and observe the flow at the suspect lifter bore. It may reveal nothing but then again, it may uncover something relevant to your problem.
#11
Supreme Member
Re: Need advice with lifter selection
Have you contacted Dart? You may want to ask them if they have any advice concerning lifter selection for use with the small base circle cam.