LZ4 + 4T65-E Swap Into an 85 Using rusEFI
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- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
LS7 1.8:1 rocker on left, LZ4 rocker screw in middle, LZ4 1.7:1 rocker on right
The shoulder on the LZ4 machine screw is ~0.4mm (0.016") too large for the LS7 rocker pivot. The LS7 rocker pivot hole will have to be opened up a bit to use the LZ4 rocker screw or maybe LS7 rocker screws are the the proper length and shoulder diameter.
LS7 1.8:1 rocker on left, LZ4 1.7:1 rocker in middle, LZ4 rocker screw on right
LS7 1.8:1 rocker is slightly longer but seems to share the same distance from pivot center to push rod. More measurements later.
LS7 rocker above with LZ4 screw. Screw stops where shoulder meets rocker pivot.
LS7 rocker on LZ4 rocker pedestal and using LZ4 screw before any mods to LS7 rocker. The contact area of the LS7 rocker to the valve stem is slightly off center of the valve stem when the valve is fully closed.
More pics to come after removing valve spring and checking the full range of motion.
GM
GEN III / GEN IV V-8
LS1/LS2/LS6 1997/2007 HARDWARE
http://www.billavista.com/tech/pdf_inde ... nsions.pdf
The shoulder on the LZ4 machine screw is ~0.4mm (0.016") too large for the LS7 rocker pivot. The LS7 rocker pivot hole will have to be opened up a bit to use the LZ4 rocker screw or maybe LS7 rocker screws are the the proper length and shoulder diameter.
LS7 1.8:1 rocker on left, LZ4 1.7:1 rocker in middle, LZ4 rocker screw on right
LS7 1.8:1 rocker is slightly longer but seems to share the same distance from pivot center to push rod. More measurements later.
LS7 rocker above with LZ4 screw. Screw stops where shoulder meets rocker pivot.
LS7 rocker on LZ4 rocker pedestal and using LZ4 screw before any mods to LS7 rocker. The contact area of the LS7 rocker to the valve stem is slightly off center of the valve stem when the valve is fully closed.
More pics to come after removing valve spring and checking the full range of motion.
GM
GEN III / GEN IV V-8
LS1/LS2/LS6 1997/2007 HARDWARE
http://www.billavista.com/tech/pdf_inde ... nsions.pdf
- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
LS7 1.8:1 rocker on LZ4 head and pedestal.
You can see the the rocker walks off to the side of the valve stem with a M8 screw installed as the valve gets lifted in the video below.
https://i.imgur.com/6ZxEpKG.mp4
You can see the the rocker walks off to the side of the valve stem with a M8 screw installed as the valve gets lifted in the video below.
https://i.imgur.com/6ZxEpKG.mp4
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- Peer Mediator
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
If you use a mill to bore that hole offset instead of just drilling it out, you can move the rocker 0.010 or so away from the valve tip to help the geometry a smidge. Is the rocker bolt an 8mm? What diameter is the shoulder?CaptainHindsight wrote: ↑Thu May 20, 2021 5:48 pm
The shoulder on the LZ4 machine screw is ~0.4mm (0.016") too large for the LS7 rocker pivot. The LS7 rocker pivot hole will have to be opened up a bit to use the LZ4 rocker screw or maybe LS7 rocker screws are the the proper length and shoulder diameter.
- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
The LZ4 pedestal, head and screw are all M8 x 1.25.
The shoulder on the LZ4 rocker screw is 8.4mm.
The through hole in the LZ4 rocker pivot is 8.4mm
The through hole in the LS7 rocker pivot is 8mm.
The wall thickness of the LS7 rocker pivot at its thinnest point is 5mm.
The shoulder on the LZ4 rocker screw is 8.4mm.
The through hole in the LZ4 rocker pivot is 8.4mm
The through hole in the LS7 rocker pivot is 8mm.
The wall thickness of the LS7 rocker pivot at its thinnest point is 5mm.
- Shaun41178(2)
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Thanks for sharing the vid. Good quality. You vould prob use the ls7 but accelerated guide wear would say occur. Just how fast they would wear out is the question.
- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
I have to see about putting an offset in to change the rocker position. I still have to check the clearances for the pushrods and the valve covers if i do so. Not sure yet how far i want to go into changing rockers, pedestals, pushrods and fabricating valve covers, etc. etc. if need be. How many HP will I gain?
Elongation of the rocker pivot through hole will weaken the pivot and require a shim to keep it from sliding.
Views of the rocker holes and pedestals. One pedestal on, one off, should be obvious.
Another pic of the LS7 1.8:1 rocker when pushing the valve down.
Elongation of the rocker pivot through hole will weaken the pivot and require a shim to keep it from sliding.
Views of the rocker holes and pedestals. One pedestal on, one off, should be obvious.
Another pic of the LS7 1.8:1 rocker when pushing the valve down.
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- Peer Mediator
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Ok, so you could move the rocker pivot up to 1.25mm away from the valve by offset-drilling the bolt hole in the cylinder head for an M10x1.5 helicoil. You could offset the rocker a further 1mm away by offset boring the bolt hole out to 10mm. A total of 2.25mm or 0.088" movement of the rocker looks like it could be enough to get the mid-lift contact centered on the valve tip.CaptainHindsight wrote: ↑Thu May 20, 2021 8:19 pm The LZ4 pedestal, head and screw are all M8 x 1.25.
The shoulder on the LZ4 rocker screw is 8.4mm.
The through hole in the LZ4 rocker pivot is 8.4mm
The through hole in the LS7 rocker pivot is 8mm.
The wall thickness of the LS7 rocker pivot at its thinnest point is 5mm.
EDIT: Hmm.... the rocker pedestal has a curved seat, so you'd have to offset bore it as well.
- Shaun41178(2)
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Thanks for sharing the pics and info about the rocker bolt. The ls7 uses an 8mm bolt as well but its probably not stepped like the lz bolt.
It seems obvious that swapping to ls7 isnt a wise choice. There would be little gains and increased side load wear to the valve guide and valves
A cam swap with bearing spacers to get more power seems like the better way to go vs trying to get more power with a rocker swap. Especially if you are tearing down the whole engine for a rebuild anyways.
Cam swaps can add 40-50 hp to an lz
It seems obvious that swapping to ls7 isnt a wise choice. There would be little gains and increased side load wear to the valve guide and valves
A cam swap with bearing spacers to get more power seems like the better way to go vs trying to get more power with a rocker swap. Especially if you are tearing down the whole engine for a rebuild anyways.
Cam swaps can add 40-50 hp to an lz
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- Peer Mediator
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
If you have the engine apart, do the machine work to use the 1.8 rockers. What I outlined is actually not that difficult... as long as it's enough which has not been established yet. If you're tearing the engine down for a build, installing bearing spacers, etc... Why would you not do simple machine work to the heads to fit 1.8 rockers? Especially if you're also doing machine work to the guides and spring seats to deal with a high lift cam...Shaun41178(2) wrote: ↑Fri May 21, 2021 10:34 am A cam swap with bearing spacers to get more power seems like the better way to go vs trying to get more power with a rocker swap. Especially if you are tearing down the whole engine for a rebuild anyways.
Cam swaps can add 40-50 hp to an lz
300 WHP from a cam/springs LZ9? Sounds like fun!
- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
I'm not planning a cam swap. I'm planning on keeping the VVT. I'm just making simple improvements for reliability and a little performance. It will be a daily driver for someone and I don't want to service much besides filters and fluids for quite a while.
If max power was the goal I can just buy an aluminum big block with a blower and run nitro methane.
https://www.shafiroff.com/chevy-drag-ra ... engine.php
https://www.steveschmidtracing.com/raci ... man-series
https://www.gochampion.com/racing-engin ... evy-1.html
If max power was the goal I can just buy an aluminum big block with a blower and run nitro methane.
https://www.shafiroff.com/chevy-drag-ra ... engine.php
https://www.steveschmidtracing.com/raci ... man-series
https://www.gochampion.com/racing-engin ... evy-1.html
- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
I'm just happy to provide useful pics, measurements and info for those that might be wondering how or what if.
The question of how to use LS7 1.8:1 rockers on LZ9/4 heads was an unanswered question on several threads here and other forums.
The question of how to use LS7 1.8:1 rockers on LZ9/4 heads was an unanswered question on several threads here and other forums.
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
I appreciate you going through and posting what you've found.
FWIW, these are comp "Magnum" roller rockers on an LZ9 cylinder head.
The shaft of the rocker arms are too wide to fit. I bought them on a whim, and figured if they didn't fit, I could install them on my truck, which has a gen III LS.
FWIW, these are comp "Magnum" roller rockers on an LZ9 cylinder head.
The shaft of the rocker arms are too wide to fit. I bought them on a whim, and figured if they didn't fit, I could install them on my truck, which has a gen III LS.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Are VVT-friendly regrinds a thing yet?
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
I think the biggest problem with this is the pressed on lobes, I think most camshaft regrinders don't like messing with them.
I'm going to measure a cam I have in storage and see about having some blanks made, eventually.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
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- Peer Mediator
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Ironically, about the easiest possible way to make low volume cams is to assemble them from lobes and shafts via heat shrink fit. However, I think adding a keyway and a key to prevent rotation of the lobe on the shaft would probably satisfy the idiots who don't want to regrind assembled cams. FFS, heat shrink press fits transmit hundreds to a few thousand ftlbs of torque in transmissions... they shouldn't be pushing that hard on the cam to regrind it.ericjon262 wrote: ↑Fri May 21, 2021 6:46 pmI think the biggest problem with this is the pressed on lobes, I think most camshaft regrinders don't like messing with them.
I'm going to measure a cam I have in storage and see about having some blanks made, eventually.
- Shaun41178(2)
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Yes. And thanks again. I had wondered for a couple years but never got around to checking myself so iy saved me time and money.CaptainHindsight wrote: ↑Fri May 21, 2021 5:28 pm I'm just happy to provide useful pics, measurements and info for those that might be wondering how or what if.
The question of how to use LS7 1.8:1 rockers on LZ9/4 heads was an unanswered question on several threads here and other forums.
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL
BEWARE OF BEN PHELPS. YOU HAVE BEEN WARNED. WORSE THAN MILZY IMO
BEWARE OF BEN PHELPS. YOU HAVE BEEN WARNED. WORSE THAN MILZY IMO
- Shaun41178(2)
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
75mm tb, cam swap, longtubes is all you need to to get 300 crank hp.The Dark Side of Will wrote: ↑Fri May 21, 2021 11:36 am l.
300 WHP from a cam/springs LZ9? Sounds like fun!
300 whp would take a bit more work obviously. Id say my 3900 without turbo would make around 250 whp. I just have a 75mm tb and cam and through a manual.
Josh riedl did 238 whp through an 4t65 with tb, cam, and homemade headers.
Header flanges are available for the lz engines. I picked up a set a while back from a place in oregon
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL
BEWARE OF BEN PHELPS. YOU HAVE BEEN WARNED. WORSE THAN MILZY IMO
BEWARE OF BEN PHELPS. YOU HAVE BEEN WARNED. WORSE THAN MILZY IMO
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
Shaun41178(2) wrote: ↑Fri May 21, 2021 11:05 pm75mm tb, cam swap, longtubes is all you need to to get 300 crank hp.The Dark Side of Will wrote: ↑Fri May 21, 2021 11:36 am l.
300 WHP from a cam/springs LZ9? Sounds like fun!
300 whp would take a bit more work obviously. Id say my 3900 without turbo would make around 250 whp. I just have a 75mm tb and cam and through a manual.
Josh riedl did 238 whp through an 4t65 with tb, cam, and homemade headers.
Header flanges are available for the lz engines. I picked up a set a while back from a place in oregon
I also have a drawing for a set of LZx flanges that I drew. hopefully before too long I'll be in a position that I can produce them myself.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
- CaptainHindsight
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
I build all sorts of custom robots and 5+ axis machines as well as additive manufacturing tech. I could print sand molds and cast aluminum rockers or cam blanks and grind them. It just more of a project than I planned.
@ericjon262 What ratio are the comp "Magnum" roller rockers? If they were to magically shrink and fit on the pedestals, how would they ride on the valve stems?
Do you know who makes the header flanges? I might pick some up vs plasma cut them.
@ericjon262 What ratio are the comp "Magnum" roller rockers? If they were to magically shrink and fit on the pedestals, how would they ride on the valve stems?
Do you know who makes the header flanges? I might pick some up vs plasma cut them.
- Shaun41178(2)
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Re: LZ4 + 4T65-E Swap Into an 85 Using rusEFI
District fabrication is where I got the flanges.
(503) 505-4456
Districtfab.com
(503) 505-4456
Districtfab.com
FieroPhrek working on that ls4 swap for 18 years and counting now. 18 years!!!!! LOL
BEWARE OF BEN PHELPS. YOU HAVE BEEN WARNED. WORSE THAN MILZY IMO
BEWARE OF BEN PHELPS. YOU HAVE BEEN WARNED. WORSE THAN MILZY IMO