that and the pilot hole on the nose of the cam is 0.5" x ~1.06" to accomodate the vented (later style) opti-spark.
SBC LT1 / vortec compatability
Moderator: Team
Re: SBC LT1 / vortec compatability
-
- Guru
- Posts: 1602
- Joined: Sat Dec 24, 2011 10:02 am
- Location: melfort saskatchewan Canada
Re: SBC LT1 / vortec compatability
so i got a little carried away and pulled the motor apart without marking the pistons. Now i see they have no numbers or notch that points to the front of the motor. However this is what they do have : B ---> stamped on the top. Does this mean back ? I've never seen an arrow or any markings telling you how to put in a piston pointing to the back.
EDIT : also the cam does look like it just has a longer dowel pin than any factory roller cams i've ever seen. I most likely won't be using it. I started cleaning up a TBI block today and its not a roller cam block. I'll likely put in the cheapest comp cam in the book. Probably one of the -2 cams.
EDIT : also the cam does look like it just has a longer dowel pin than any factory roller cams i've ever seen. I most likely won't be using it. I started cleaning up a TBI block today and its not a roller cam block. I'll likely put in the cheapest comp cam in the book. Probably one of the -2 cams.
The Word of God is quick and powerfull
www.therocketshop.blogspot.com
www.therocketshop.blogspot.com
-
- Guru
- Posts: 8686
- Joined: Sun Jan 21, 2007 1:16 pm
- Location: Victoria BC Canada
Re: SBC LT1 / vortec compatability
I just built a LT-1 and the center of the cam nose is drilled deeper as well as a longer locating pin.
A regular cam gear fits but it has to be the deeper recessed gear to clear the cam retainer button head torx fasteners.
They also make a good true roller 9 keyway lower gear setup as well to fit both the LT-1 lt-4 and the vortec style cam drive parts
Real Race Cars Don't Have Doors
-
- Expert
- Posts: 674
- Joined: Sun Aug 10, 2008 11:51 am
- Location:
Re: SBC LT1 / vortec compatability
Any timing gear made for the stepped-nose cams, either 87-93 Gen1 or LT1/LT4, should have clearance for the cam retainer plate and bolts, as the stepped-nose cams were never used without the retainer plate. Changing to a different style bolt with a fatter head can cause clearance issues. Some aftermarket timing sets didn't allow quite enough clearance on the backside of the cam gear, though they don't technically hit anything it's common to grind a tiny bit off the heads of the retainer bolts just for peace of mind.
The dimensions of the stepped cam nose, either Gen1 or LT1, are the same. Bolt pattern is the same.
Aftermarket cams sold as "LT1/LT4" that have the long dowel also have a deeper hole behind the dowel, so that the cam can be retrofitted to Gen1's by simply driving the dowel in deeper to match the Gen1 length. Factory LT1/LT4 cams may not have the deeper hole in the cam and so require either cutting the dowel or pulling it and replacing it with a shorter one.
The service manual says:
The dimensions of the stepped cam nose, either Gen1 or LT1, are the same. Bolt pattern is the same.
Aftermarket cams sold as "LT1/LT4" that have the long dowel also have a deeper hole behind the dowel, so that the cam can be retrofitted to Gen1's by simply driving the dowel in deeper to match the Gen1 length. Factory LT1/LT4 cams may not have the deeper hole in the cam and so require either cutting the dowel or pulling it and replacing it with a shorter one.
The service manual says:
When installing the piston and the connecting rod, the stamped arrow on the piston must point to the front of the engine while the flange on the connecting rod must face toward the front of the piston on the left-hand side and face toward the rear of the piston on the right-hand side.
DON'T PANIC
-
- Guru
- Posts: 8686
- Joined: Sun Jan 21, 2007 1:16 pm
- Location: Victoria BC Canada
Re: SBC LT1 / vortec compatability
Cloyes has a factory roller cam specificd double true roller 9 key way setup.turbo camino wrote: ↑Thu Oct 01, 2020 9:56 pm Any timing gear made for the stepped-nose cams, either 87-93 Gen1 or LT1/LT4, should have clearance for the cam retainer plate and bolts, as the stepped-nose cams were never used without the retainer plate. Changing to a different style bolt with a fatter head can cause clearance issues. Some aftermarket timing sets didn't allow quite enough clearance on the backside of the cam gear, though they don't technically hit anything it's common to grind a tiny bit off the heads of the retainer bolts just for peace of mind.
The dimensions of the stepped cam nose, either Gen1 or LT1, are the same. Bolt pattern is the same.
Aftermarket cams sold as "LT1/LT4" that have the long dowel also have a deeper hole behind the dowel, so that the cam can be retrofitted to Gen1's by simply driving the dowel in deeper to match the Gen1 length. Factory LT1/LT4 cams may not have the deeper hole in the cam and so require either cutting the dowel or pulling it and replacing it with a shorter one.
The service manual says:When installing the piston and the connecting rod, the stamped arrow on the piston must point to the front of the engine while the flange on the connecting rod must face toward the front of the piston on the left-hand side and face toward the rear of the piston on the right-hand side.
It fits all timing covers with lots of clearance including the plastic covers.
Makes a nice change from the sloppy sets as they can be had in -.005 and -.010 shorter lengths.
No block grinding required. I have used maybe 30 of them to date all applications no issues.
Real Race Cars Don't Have Doors
Re: SBC LT1 / vortec compatability
The short answer is "YES"prairiehotrodder wrote: ↑Mon Sep 07, 2020 10:00 pm will the cam / lifters and the rods / pistons out of a 93 buick roadmaster LT1 go into a 96-98 350 vortec truck engine ? I have the roadmaster engine and i'm trying to build another ultra low buck JY motor for my sons jr. street drag car 1980 malibu 4 door. I haven't taken the motor apart yet but i 'm thinking it might have factory flat top pistons, powder metal rods and a bigger cam than the vortec truck motor ? can anyone verify this ?
Brian
Re: SBC LT1 / vortec compatability
You have a part# for that double roller that fits all blocks?ProPower engines wrote: ↑Thu Oct 01, 2020 10:00 pmCloyes has a factory roller cam specificd double true roller 9 key way setup.turbo camino wrote: ↑Thu Oct 01, 2020 9:56 pm Any timing gear made for the stepped-nose cams, either 87-93 Gen1 or LT1/LT4, should have clearance for the cam retainer plate and bolts, as the stepped-nose cams were never used without the retainer plate. Changing to a different style bolt with a fatter head can cause clearance issues. Some aftermarket timing sets didn't allow quite enough clearance on the backside of the cam gear, though they don't technically hit anything it's common to grind a tiny bit off the heads of the retainer bolts just for peace of mind.
The dimensions of the stepped cam nose, either Gen1 or LT1, are the same. Bolt pattern is the same.
Aftermarket cams sold as "LT1/LT4" that have the long dowel also have a deeper hole behind the dowel, so that the cam can be retrofitted to Gen1's by simply driving the dowel in deeper to match the Gen1 length. Factory LT1/LT4 cams may not have the deeper hole in the cam and so require either cutting the dowel or pulling it and replacing it with a shorter one.
The service manual says:When installing the piston and the connecting rod, the stamped arrow on the piston must point to the front of the engine while the flange on the connecting rod must face toward the front of the piston on the left-hand side and face toward the rear of the piston on the right-hand side.
It fits all timing covers with lots of clearance including the plastic covers.
Makes a nice change from the sloppy sets as they can be had in -.005 and -.010 shorter lengths.
No block grinding required. I have used maybe 30 of them to date all applications no issues.
Does it Even the opti spark Aluminum cover?
-
- Guru
- Posts: 1602
- Joined: Sat Dec 24, 2011 10:02 am
- Location: melfort saskatchewan Canada
Re: SBC LT1 / vortec compatability
it does have flat tops but it has the normal old style forged connecting rods.1980RS wrote: ↑Fri Oct 02, 2020 9:52 amThe short answer is "YES"prairiehotrodder wrote: ↑Mon Sep 07, 2020 10:00 pm will the cam / lifters and the rods / pistons out of a 93 buick roadmaster LT1 go into a 96-98 350 vortec truck engine ? I have the roadmaster engine and i'm trying to build another ultra low buck JY motor for my sons jr. street drag car 1980 malibu 4 door. I haven't taken the motor apart yet but i 'm thinking it might have factory flat top pistons, powder metal rods and a bigger cam than the vortec truck motor ? can anyone verify this ?
Brian
Does anyone know what this means : B---> on the top of the piston ?
The Word of God is quick and powerfull
www.therocketshop.blogspot.com
www.therocketshop.blogspot.com
-
- Guru
- Posts: 8686
- Joined: Sun Jan 21, 2007 1:16 pm
- Location: Victoria BC Canada
Re: SBC LT1 / vortec compatability
[/quote]
Cloyes has a factory roller cam specificd double true roller 9 key way setup.
It fits all timing covers with lots of clearance including the plastic covers.
Makes a nice change from the sloppy sets as they can be had in -.005 and -.010 shorter lengths.
No block grinding required. I have used maybe 30 of them to date all applications no issues.
[/quote]
You have a part# for that double roller that fits all blocks?
Does it Even the opti spark Aluminum cover?
[/quote]
There is a specific timing set for the LT-1/LT-4 but there is also a set for the late model 1 piece rear seal blocks which covers from 89 to 2000ish. Also available in -.005 and .010 shorter.
FYI they are in the thin Cloyes supplemental HP catalogue but when I get time I can look them up again
for you or contact cloyes directly.
I also believe there is a couple other brands I have seen as well but chain was off shore gears US made.
Cloyes has a factory roller cam specificd double true roller 9 key way setup.
It fits all timing covers with lots of clearance including the plastic covers.
Makes a nice change from the sloppy sets as they can be had in -.005 and -.010 shorter lengths.
No block grinding required. I have used maybe 30 of them to date all applications no issues.
[/quote]
You have a part# for that double roller that fits all blocks?
Does it Even the opti spark Aluminum cover?
[/quote]
There is a specific timing set for the LT-1/LT-4 but there is also a set for the late model 1 piece rear seal blocks which covers from 89 to 2000ish. Also available in -.005 and .010 shorter.
FYI they are in the thin Cloyes supplemental HP catalogue but when I get time I can look them up again
for you or contact cloyes directly.
I also believe there is a couple other brands I have seen as well but chain was off shore gears US made.
Real Race Cars Don't Have Doors
Re: SBC LT1 / vortec compatability
Why all this parts swapping. Why are you not running the
complete 350 LT-1 engine as is?
complete 350 LT-1 engine as is?
-
- Expert
- Posts: 674
- Joined: Sun Aug 10, 2008 11:51 am
- Location:
Re: SBC LT1 / vortec compatability
From a few replies back:prairiehotrodder wrote: ↑Fri Oct 02, 2020 10:46 am it does have flat tops but it has the normal old style forged connecting rods.
Does anyone know what this means : B---> on the top of the piston ?
If there is something that looks like an arrow, it points to the front.When installing the piston and the connecting rod, the stamped arrow on the piston must point to the front of the engine while the flange on the connecting rod must face toward the front of the piston on the left-hand side and face toward the rear of the piston on the right-hand side.
The L31 PM rods are better than the old rods. As was said very early on in this thread, there's nothing special or better about the LT1 internals.
DON'T PANIC
Re: SBC LT1 / vortec compatability
Just a note on driving that longer pin in. I just got done with a build using an LT4 HotCam. That pin wouldn't move and began to mushroom and bend. So I cut it to length and dressed the end. I don't know if you could save the cam if that pin broke off but I for one wouldn't want to try.
Re: SBC LT1 / vortec compatability
Cloyes has a factory roller cam specificd double true roller 9 key way setup.
It fits all timing covers with lots of clearance including the plastic covers.
Makes a nice change from the sloppy sets as they can be had in -.005 and -.010 shorter lengths.
No block grinding required. I have used maybe 30 of them to date all applications no issues.
[/quote]
You have a part# for that double roller that fits all blocks?
Does it Even the opti spark Aluminum cover?
[/quote]
There is a specific timing set for the LT-1/LT-4 but there is also a set for the late model 1 piece rear seal blocks which covers from 89 to 2000ish. Also available in -.005 and .010 shorter.
FYI they are in the thin Cloyes supplemental HP catalogue but when I get time I can look them up again
for you or contact cloyes directly.
I also believe there is a couple other brands I have seen as well but chain was off shore gears US made.
[/quote]
The double roller part # for the LT1 with one piece rear seal and opti spark Is what I’m looking for
-
- Expert
- Posts: 674
- Joined: Sun Aug 10, 2008 11:51 am
- Location:
Re: SBC LT1 / vortec compatability
Yes. Seems like someone already mentioned this, about GM cams and aftermarket being different in how they deal with the dowel pin thing and backwards compatibility...Monzsta wrote: ↑Fri Oct 02, 2020 9:04 pm Just a note on driving that longer pin in. I just got done with a build using an LT4 HotCam. That pin wouldn't move and began to mushroom and bend. So I cut it to length and dressed the end. I don't know if you could save the cam if that pin broke off but I for one wouldn't want to try.
DON'T PANIC
Re: SBC LT1 / vortec compatability
When I worked for GMC back in the late 90's they were using all the left over LT1-4 bottom ends in the 1 ton trucks. I bought a core engine that had low oil pressure at Idle. Pulled it apart and the 350 had a forged steel crank, 4 bolt main, windage tray and PM rods. Pretty good deal for $50 with 8K on it. If I take it apart I will just stick a HV oil pump in it as it spins to 6500 pretty easy. All the LT1 bottom end stuff changes with the Vortec stuff.