Cam swap?
10-09-2006, 04:54 PM
#1
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Cam swap? After reading the following paragraph from GM High-Tech Performance, it seems a person can swap a new cam into my LQ4 and reuse the factory lifters. In the old days that was a no-no. Is that no longer the case?
"Considering that they are made out of plastic, it's surprising that the trays grab onto the lifters firmly enough to ensure they won't fall out as the tray is being handled. This grab action also means that, once installed, the lifters can't move without an external force: either the cam lobe must push them up, or the pushrod/rocker/valvespring must push them down. So, if you remove your rocker arms and spin the crankshaft over two full revolutions, the lobes will push all the lifters up; with the trays holding them away from the cam, this allows a heads-on cam swap! This is a pretty nice feature for enthusiasts that GM has incorporated. To install, simply line up the lifters with their respective bores and slide the trays into the block; torque the retainer bolt to 106 in-lb."
Thanks
"Considering that they are made out of plastic, it's surprising that the trays grab onto the lifters firmly enough to ensure they won't fall out as the tray is being handled. This grab action also means that, once installed, the lifters can't move without an external force: either the cam lobe must push them up, or the pushrod/rocker/valvespring must push them down. So, if you remove your rocker arms and spin the crankshaft over two full revolutions, the lobes will push all the lifters up; with the trays holding them away from the cam, this allows a heads-on cam swap! This is a pretty nice feature for enthusiasts that GM has incorporated. To install, simply line up the lifters with their respective bores and slide the trays into the block; torque the retainer bolt to 106 in-lb."
Thanks
10-10-2006, 09:27 AM
#4
Originally Posted by AaronH
After reading the following paragraph from GM High-Tech Performance, it seems a person can swap a new cam into my LQ4 and reuse the factory lifters. In the old days that was a no-no. Is that no longer the case?
"Considering that they are made out of plastic, it's surprising that the trays grab onto the lifters firmly enough to ensure they won't fall out as the tray is being handled. This grab action also means that, once installed, the lifters can't move without an external force: either the cam lobe must push them up, or the pushrod/rocker/valvespring must push them down. So, if you remove your rocker arms and spin the crankshaft over two full revolutions, the lobes will push all the lifters up; with the trays holding them away from the cam, this allows a heads-on cam swap! This is a pretty nice feature for enthusiasts that GM has incorporated. To install, simply line up the lifters with their respective bores and slide the trays into the block; torque the retainer bolt to 106 in-lb."
Thanks
"Considering that they are made out of plastic, it's surprising that the trays grab onto the lifters firmly enough to ensure they won't fall out as the tray is being handled. This grab action also means that, once installed, the lifters can't move without an external force: either the cam lobe must push them up, or the pushrod/rocker/valvespring must push them down. So, if you remove your rocker arms and spin the crankshaft over two full revolutions, the lobes will push all the lifters up; with the trays holding them away from the cam, this allows a heads-on cam swap! This is a pretty nice feature for enthusiasts that GM has incorporated. To install, simply line up the lifters with their respective bores and slide the trays into the block; torque the retainer bolt to 106 in-lb."
Thanks
You really can't trust those plastic thingies to hold the lifters up on a used engine. I've done cam changes on about 5 engines here and they held up ok on 3 of them but on 2 of the engines at least one lifter would not stay up. When I ran into the first one that wouldn't hold up I bought the correct tool that slides in from the front of the engine and physically holds the lifters up!
If a lifter drops while the cam is out, it's off with the head!
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91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
91 Z28 LS2 408CI, LS9 Supercharger, LPE GT7 cam, Yank3000, 3450 raceweight.
Latest numbers: 9.71 ET, 141.42 MPH, 1.40 60' , 610 RWHP Mustang Dyno
www.speartech.com
10-10-2006, 10:20 AM
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Those lifter trays aren't installed to hold the lifters up for cam swaps -- they are there to keep the lifters from spinning in their bores. Its definitely safer to stick a couple lengths of 5/16" dowel rod in the front of the motor to retain the lifters like John mentioned above.
Its definitely safer to stick a couple lengths of 5/16" dowel rod in the front of the motor to retain the lifters like John mentioned above.
10-10-2006, 03:08 PM
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Some issues that I'm having Thanks for everone's input.
I took the Jeep on a thousand mile road trip two weeks ago. The 6.0L has always ran around 26 PSI oil pressure-hot or cold. This is based on an autometer gauge plumbed at the back of the block. While I was driving on the interstate at 75 MPH and 3400 RPM I noticed that the pressure actually dropped to about 23PSI. It shouldn't do that. So I have been thinking about what I'm going to do. I need to swap the oil pan anyway because the truck pan hangs lower than I feel comfortable with since the Jeep sees alot of rocks. I can do pretty much any pan I want, the more shallow the better. I have been watching for a deal on a F-body or 'Vette pan. Anyway, how do I cure my pressure problem? New oil pump? If so, thought about doing a cam. Then again, I want low end idle/off idle torque. Can the factory cam be beat? I dunno. Just some thoughts running through my head. The big question, how do I definatively cure my oil pressure problem? Other threads about this don't really provide an answer.
BTW- Fastkat, do you know what pressure that 6.0 had in the donor vehicle? Do you have any useable pans from an F-nody or 'vette you are not using?
Thanks All
I took the Jeep on a thousand mile road trip two weeks ago. The 6.0L has always ran around 26 PSI oil pressure-hot or cold. This is based on an autometer gauge plumbed at the back of the block. While I was driving on the interstate at 75 MPH and 3400 RPM I noticed that the pressure actually dropped to about 23PSI. It shouldn't do that. So I have been thinking about what I'm going to do. I need to swap the oil pan anyway because the truck pan hangs lower than I feel comfortable with since the Jeep sees alot of rocks. I can do pretty much any pan I want, the more shallow the better. I have been watching for a deal on a F-body or 'Vette pan. Anyway, how do I cure my pressure problem? New oil pump? If so, thought about doing a cam. Then again, I want low end idle/off idle torque. Can the factory cam be beat? I dunno. Just some thoughts running through my head. The big question, how do I definatively cure my oil pressure problem? Other threads about this don't really provide an answer.
BTW- Fastkat, do you know what pressure that 6.0 had in the donor vehicle? Do you have any useable pans from an F-nody or 'vette you are not using?
Thanks All
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10-10-2006, 05:44 PM
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i think that in a jeep that stock cam is pretty much all you need. its not like you are strained for power, it has at least 350 ft lbs of torque.
honestly i think you just just leave it alone
honestly i think you just just leave it alone
10-10-2006, 05:54 PM
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Cop Car- I think you are right. I'm afraid to dump the clutch now with 33x12.50 Goodyear MTRs because I get the sensation that something is going to break and break big. Truth is, it just passed through my mind. I'd really like to just get the pan swapped and the oil pressure fixed.
Thanks
Thanks
10-11-2006, 05:23 PM
#10
I upraded my stock oil pump to a katech ported pump during a cam swap and and with an electric autometer gauge plumbed into the back of the block it only has about 30-40 psi at idle. the reason I say only is on several of my friends 4th gens with this pump and stock gauges read about 50-65 at idle. so i dont know if i trust the electric gauge.As for your oil pan, I ordered mine thru gmpartsdirect.com. To change pans you will also need a windage tray,pump pick up tube, and dipstick.the cost of it all was around $200