SBC early cam into vortech block?

[KnightEngines]

What's the deal with sticking an earlier style cam with no thrust plate provision into a vortech block with thrust plate?

Just throw away the thrust plate & use an earlier style timing kit?

[In-Tech]

Yes, you have it right. Most mid 90's SBC's in trucks were machined for hyd roller and still used a flat tappet. If the block is machined for the hyd roller why would you not use that setup? It doesn't cost that much more if you are building from scratch. Anyway, hope that helps.

[KnightEngines]

Customer already has a rollmaster timing kit for early block, cams cost much the same, so I'll just use it since he's got it. Solid roller this one.

Thanks for the confirmation.

[GOSFAST]

What's the deal with sticking an earlier style cam with no thrust plate provision into a vortech block with thrust plate?

Just throw away the thrust plate & use an earlier style timing kit?

Just wrapped up 2 Vortec block builds, you MAY have a major issue fitting that early timing set in that block. Won't know till you get up to that point??

We just developed our own method to do the opposite of what you're doing, we can put the later style (roller) cams in the early blocks without the need for any cam buttons or chasing end-play. We fabricated tooling to install a late style G.M. thrust plate with the 2 mounting screws. We've actually been selling these tooling pkges to prep the blocks. Much nicer and quicker doing retro-roller assemblies now with these early castings.

Thanks, Gary in N.Y.

P.S. One of our blocks was a production line deal the other one came as a ZZ383" over-the-counter. Both have the same casting number (10243880), and both are 100% entirely different castings. If you go with a conventional timing cover the chain fits better, just check for clearance behind the chain and cam gear at the top oil galley plug, the block may need some grinding. Also there are 2 damper lengths from the face of the damper to the rear of the hub!

[In-Tech]

Good call Gary, I forgot to mention about clearancing for the double row timing set. Sucks to find that out after the short is assembled Of course I've never done that

[ProPower engines]

There is a HP true roller set specific timing set for use with a FT cam in the roller blocks.
It has a undercut section on the block side to clear the taller wider area around the cam tunnel.
There is also a single roller set that was used as well. It has a 1/2" wide roller chain used for 89-95 350 HD truck and marine engines with FT cams
Both are by Cloyes that I know of but there are other brands I am sure

[KnightEngines]

Thanks for the heads up, I'll dummy up the cam etc while I'm checking deck heights & clearance where it's needed. Running an early style front cover, so should be ok there.

[KnightEngines]

Last piece of the puzzle - harmonic balancer is being reused, it's a decent 8" profession products balancer.
Rollmaster crank gear is fatter than the original single row chain gear, so the balancer will sit further out.
Can I just machine the difference off the back of the balancer so it fits in the same position or is that gonna interfere with the front cover? - didn't think to check that when I had it dummied up, don't want to dummy it again just to check!
I'll be using an early style front cover if that makes a difference.

As far as I can see there won't be an issue just machining the balancer to suit, but I'd rather not do it & find a problem later!

[cjperformance]

Good call Gary, I forgot to mention about clearancing for the double row timing set. Sucks to find that out after the short is assembled Of course I've never done that

me either !!

Tony, i have just fitted the balancer as is, customer then supplied a pulley and bracket kit and the cranc pulley still needed to be spaced ~.100" further out aswell. Unless you have the pulleys etc i would not cut the balancer yet.

[GOSFAST]

The pulley alignment between the damper and the other pulley's is the last item you'd check. It is important.

The conventional crank timing gears measure .595", the Vortec's measure .522". Can't say what your exact "fix" will be but it must be checked beforehand.

Thanks, Gary in N.Y.

P.S. With the above numbers you can see there is a .072" (nominal) difference between the conventional SBC crank gear and the "thin" gear found on most Vortec units! In short, if you install the earlier timing set and want to use a conventional damper it will need to be shortened by that .072" number OR you'll need to start spacing out the pulleys!

[peejay]

The pulley alignment between the damper and the other pulley's is the last item you'd check. It is important.

The conventional crank timing gears measure .595", the Vortec's measure .522". Can't say what your exact "fix" will be but it must be checked beforehand.

Thanks, Gary in N.Y.

P.S. With the above numbers you can see there is a .072" (nominal) difference between the conventional SBC crank gear and the "thin" gear found on most Vortec units! In short, if you install the earlier timing set and want to use a conventional damper it will need to be shortened by that .072" number OR you'll need to start spacing out the pulleys!

Don't all Vortecs (the ones with the goofy plastic timing cover) have a sheetmetal trigger wheel in front of the crank pulley? I have a gut feeling they are about .072" thick in the center...

[rfoll]

I trimmed the trigger wheel and used it as a spacer. This allowed me to re-use the stock balancer and a conventional timing cover.