[Hogg]

I get asked this question a lot and there are a lot of ways to answer it.

Can a 400 SBC be installed in place of a Vortec 350 L31, using the Vortec heads, roller cam, the plastic front timing cover(that holds the crank position sensor) with the stock 4x reluctor underneath.
L31 reluctor wheel


Vortec timing cover left/older timing cover right


A Vortec block, notice where the bolt on camshaft retainer goes, this will be absent from a stock 400 SBC



So how do I retain the ROLLER cam in my Vortec headed 400SBC?
What compression would flattop pistons give with the 64cc Vortec chambers roughly, assuming conventional 400sbc gasket comnpressed thicknesses?

Also, the Vortec 350 uses a damper than is thinner than conventional dampers in oder to allow for the thickness of the reluctor wheel under the front timing cover. IIRC the Vortec 350 is a GEEN 1-E engine that uses a neutral damper with a counterweighted flexplate as its a 1 piece RMS engine. What would I need to use for a flexplate and damper as the 400 is a GEN 1 externally balanced engine with a 2 piece RMS.? If a weighted damper is needed I would have to run it in the lathe and trim down slightly. How would I get this attached to my 4l60e trans? Starter?

Thanks in advance guys, your answers will be helping many people beyond myself.

peace
Hog

[DoubleVision]

The roller cam in the 400 is out, why is because the depth of the roller lifters is considerably taller than the flat tappet blocks. If you look at a vortec block in comparison to the flat tappet block you'll see the difference in the lifter bore heights. The Stock roller tappets in a flat tappet block would cause the grooves in the lifters not to be lined up with the oil galleys in the lifter bores and oil would be shooting up from around the lifters everywhere and thus causing somewhat erratic oil pressure readings. You would also have to figure out a way to get a spider holder in the lifter valley plus modify the area above the lifter bores to accept the dog bones which keeps the lifters from spinning in the bores. You'll also notice the plastic timing cover and the stamped cover all the bolts don't line up. There's 2 that aren't present on the new school cover compared with the old school. As you said the 400 is externally balanced so you cannot use a 350 balancer and flexplate on it, it must use the 400 externally balanced pieces. If you attempt to use a 350 balancer on a 400 it will quickly destroy the crank bearings. You could have the length of the 400 balancer machined down to match the length of the 350balancer. True flat top pistons in a 400 with Vortec heads would put the compression up around the 10.75:1 to 11:1 figures, way too high for pump gas, especially using the short 5.565 400 rod. You would have to have a cam button on the front of the cam to prevent cam walk, you can buy these from summit or jegs, I believe crane and other companies all make these. They fit in the snout of the crank and is bolted in place by a ring that bolts on to the cam and has bend locks on them to prevent the bolts from backing out. Then you have to set the clearance between the cam button and the timing cover. If it's too tight it won't last long and if it's too loose it will cause cam and lifter damage. If you want your Vortec motor to have more get up and go, then stick with the Vortec block and throw a Scat 1 piece seal internally balanced 3.750 inch stroke crank in it. This way you could reuse the Vortec Balancer and flexplate. Then you could also use the factory cam retainer and you wouldn't have to modify and grind away in the lifter valley to make it all work. If you go this route you would likely come out cheaper with far less work involved. If you were to take this route make sure you get a Cloyes "Vortec" timing set which consists of a large single roller. This set has to be used for clearance purposes.
I've heard there are books out there that show how to use factory roller tappet stuff in older flat tappet blocks but I would think it would be somewhat shakey.

[cobalt327]

Originally Posted by Hogg

I get asked this question a lot and there are a lot of ways to answer it.

Can a 400 SBC be installed in place of a Vortec 350 L31, using the Vortec heads, roller cam, the plastic front timing cover(that holds the crank position sensor) with the stock 4x reluctor underneath.

So how do I retain the ROLLER cam in my Vortec headed 400SBC?
What compression would flattop pistons give with the 64cc Vortec chambers roughly, assuming conventional 400sbc gasket comnpressed thicknesses?

Also, the Vortec 350 uses a damper than is thinner than conventional dampers in oder to allow for the thickness of the reluctor wheel under the front timing cover. IIRC the Vortec 350 is a GEEN 1-E engine that uses a neutral damper with a counterweighted flexplate as its a 1 piece RMS engine. What would I need to use for a flexplate and damper as the 400 is a GEN 1 externally balanced engine with a 2 piece RMS.? If a weighted damper is needed I would have to run it in the lathe and trim down slightly. How would I get this attached to my 4l60e trans? Starter?

Thanks in advance guys, your answers will be helping many people beyond myself.

peace
Hog

Some more info on the timing cover and damper: http://www.crankshaftcoalition.com/w...er_replacement

The Vortec neutral balanced damper has a shorter snout to allow for the reluctor wheel to fit. If you don't need the reluctor wheel, you can use a normal 400 balancer. If you need the reluctor wheel, the 400 balancer will need to be made shorter.

The cam would be retained using a cam button, like used for a retro roller cam setup.

The lifters that are supposed to work for this are the 2.2L, 3.1L or 3.4L Chevy engines. They're shorter, and require a pushrod about 7.5" long.

Some threads (I'm sure there are many more, these are two I bookmarked awhile back:
Roller Cam Conversion - ChevyTalk --The Social Network for Chevy Fans
retro hit hyd roller cam in oe roller block?

CR calculators

[icsamerica]

Why not use retrofit rollers lifter and a cam button? You can also use an internal balance rotating assembly for the 400 and reuse your neutral damper and get a neutral flywheel.

Originally Posted by DoubleVision

The roller cam in the 400 is out, why is because the depth of the roller lifters is

True but there is way using shorter V6 roller lifters...I did it for a SBC 406 build with 7000 RPM redline and made a video too. I choose stock lifter becasue they are much lighter than retrofit link bar liftes but in a low RPM truck motor link bar retro lifters will suffice.

Small Block Chevy Gen1 SBC roller lifter retrofit - YouTube
considerably taller than the flat tappet blocks. .

[Hogg]

Thanks for the input thus far.

On the cam button, do you guys feel that the stock plastic Vortec timing cover would be up to the task? Maybe epoxy or rivet thin piece of sheetmetal inside the timing cover for the cam button to ride on?

I have to retain the CKP sensor and 4x reluctor ring.

I'll go through the links and post back.

Any other input?

peace
Hog

[cobalt327]

Originally Posted by Hogg

Thanks for the input thus far.

On the cam button, do you guys feel that the stock plastic Vortec timing cover would be up to the task? Maybe epoxy or rivet thin piece of sheetmetal inside the timing cover for the cam button to ride on?

I have to retain the CKP sensor and 4x reluctor ring.

I'll go through the links and post back.

Any other input?

peace
Hog

The idea is to use the reluctor, right? When I got my first L31, I looked for a steel cover that would fit using the reluctor wheel and found nothing.

I think you're in pretty much uncharted territory using a plastic cover w/a button. The plastic cover is about the same stiffness as a tin cover but like you said the plastic will wear, so I would recommend you use something inside the cover to protect the plastic, as well as outside to increase the stiffness if you can.

[GMC boogie]

Hogg, You really need to run about a 20-22cc dish piston in that combo for a more fuel friendly 9.5ish CR.

Flat tops will put you over 11:1 with a 4.155 bore and 64cc chambers. Most production Vortecs run in the 62-63 range.

[oldbogie]

Originally Posted by Hogg

I get asked this question a lot and there are a lot of ways to answer it.

Can a 400 SBC be installed in place of a Vortec 350 L31, using the Vortec heads, roller cam, the plastic front timing cover(that holds the crank position sensor) with the stock 4x reluctor underneath.
L31 reluctor wheel


Vortec timing cover left/older timing cover right


A Vortec block, notice where the bolt on camshaft retainer goes, this will be absent from a stock 400 SBC



So how do I retain the ROLLER cam in my Vortec headed 400SBC?
What compression would flattop pistons give with the 64cc Vortec chambers roughly, assuming conventional 400sbc gasket comnpressed thicknesses?

Also, the Vortec 350 uses a damper than is thinner than conventional dampers in oder to allow for the thickness of the reluctor wheel under the front timing cover. IIRC the Vortec 350 is a GEEN 1-E engine that uses a neutral damper with a counterweighted flexplate as its a 1 piece RMS engine. What would I need to use for a flexplate and damper as the 400 is a GEN 1 externally balanced engine with a 2 piece RMS.? If a weighted damper is needed I would have to run it in the lathe and trim down slightly. How would I get this attached to my 4l60e trans? Starter?

Thanks in advance guys, your answers will be helping many people beyond myself.

peace
Hog

Hog, I've read this over a few times over the past couple days, finding it pretty interesting. I have not built a Gen I with a roller cam to use the plastic timing cover to get the reluctor sensor to run the L31 engine management system. As in the old Laugh In days, "Veeery Interesting"!

I found myself thinking along the lines of Cobalt as to putting a thin sheet steel reinforcement on the cover with some sort of a mechanical fastener that can be sealed up so it doesn't leak oil. I suppose a nut and bolt arraingement or rivets. I think actually a sandwhich of steel with a fairly thin piece on the inside just for the cam button to wear agianst which perhaps a thicker piece on the exterior to provide stiffness. Then I support that with an aftermarket water pump that has the threaded boss on the bottom that is used for a bolt that contacts the cover to actually react the thrust load into a the engine's structure. The real amount of thrust load can vary quite a bit from very little to actually quite a bit this depending on how well aligned the machining of the crankshaft and cam mains are in relation to each other as well as the thrust surfaces of the block and timing gears and the gears themselves in relation to their alignment with each other. The worst case is a load large enough to squeeze the plastic cover out from between the steel sandwich. But in most cases this tends to be a lot less than that.

Of course the next is the old problem of mounting the spider but the included Youtube video is pretty good, I even see some of my own poorly written work comes back to haunt me. What I've done is to drill through the oil galley top into the oil passages that feed 2, 3,and 4 cam and main bearings tapping the upper casting and about 1/2 inch into the oil feed then making a 5/16th bolt for the application that has a reduced diameter where it passes inside the galley passage which extends into that portion that feeds into the upper oil passage. The intent is to provide a two point thread contact to keep the bolt from working on the threads in the upper portion of the main oil passage casting. I've also been mulling drilling and tapping the boss between the lifter bores to install a stud that would pass through a drilled hole made into the dog bone and allowing it to rock on an inverted castlated nut or short length of spring retained by a lock nut. Haven't done this but it sits on my mind for some future test engine project.

Bogie

[cobalt327]

Another thread that has some info on using lifter guides instead of dogbones: Question About A 350 Roller Setup

It can be researched further to see if it's something that you may want to try.

[Hogg]

Originally Posted by oldbogie

Hog, I've read this over a few times over the past couple days, finding it pretty interesting. I have not built a Gen I with a roller cam to use the plastic timing cover to get the reluctor sensor to run the L31 engine management system. As in the old Laugh In days, "Veeery Interesting"!


What I've done is to drill through the oil galley top into the oil passages that feed 2, 3,and 4 cam and main bearings tapping the upper casting and about 1/2 inch into the oil feed then making a 5/16th bolt for the application that has a reduced diameter where it passes inside the galley passage which extends into that portion that feeds into the upper oil passage. The intent is to provide a two point thread contact to keep the bolt from working on the threads in the upper portion of the main oil passage casting.

Bogie

I also find this "Verrrrry interrrrresting" lol

Let me see if I have this straight. You drill through the upper part of the oil galley, through the oil galley, and then continue drilling into the bottom surface of the oil galley?
Then you fab up a stud which threads through the upper surface, and into the lower surface. The stud area of the stud which is exposed to the oil galley is machined smaller(assuming no threads) so that oil flow is NOT impeded?

This would contrast simply drilling through the upper surface of the oil galley, tapping the same hole, then installing a stud into that hole?

Do I have this straight?

I guess it all comes down to cost. Do the 400 SBC with roller cam/reluctor wheel mods, OR use the Vortec 350 block and do an offest ground crank and overbore to make a 391-396 SBC.
I see that Speed-o-Motive offers these stroker kits but I have heard "stories" about their quality.


thanks

peace
Hog

[cobalt327]

Originally Posted by Hogg

I guess it all comes down to cost. Do the 400 SBC with roller cam/reluctor wheel mods, OR use the Vortec 350 block and do an offest ground crank and overbore to make a 391-396 SBC.
I see that Speed-o-Motive offers these stroker kits but I have heard "stories" about their quality.


thanks

peace
Hog

With the 400 unless the roller cam is a "must", using a flat tappet will solve the problems w/the cam.

To run the reluctor wheel will require a shortened snout on the 400 balancer and the use of a Vortec-type plastic timing cover.

Decide on the induction, configure the ECM to match the combo. Gas it up and go.

[oldbogie]

Originally Posted by Hogg

I also find this "Verrrrry interrrrresting" lol

Let me see if I have this straight. You drill through the upper part of the oil galley, through the oil galley, and then continue drilling into the bottom surface of the oil galley?
Then you fab up a stud which threads through the upper surface, and into the lower surface. The stud area of the stud which is exposed to the oil galley is machined smaller(assuming no threads) so that oil flow is NOT impeded?

This would contrast simply drilling through the upper surface of the oil galley, tapping the same hole, then installing a stud into that hole?

Do I have this straight?

I guess it all comes down to cost. Do the 400 SBC with roller cam/reluctor wheel mods, OR use the Vortec 350 block and do an offest ground crank and overbore to make a 391-396 SBC.
I see that Speed-o-Motive offers these stroker kits but I have heard "stories" about their quality.


thanks

peace
Hog

You have me straight I've done Gen I non roller blocks two ways.

1) Plan A

- Drill, after locating where to drill, into the center oil passage casting using a 17/64ths bit if you have one if not 1/4qtr is close enough.

- Then tap the hole for a 5/16ths by 18 threads. The casting is actually pretty thick in this area, almost as thick as a 5/16th's nut so it probably has enough strength to hold the spider as it doesn't see much operational load. Probably the greatest risk of damage to the hold down fasteners is clumsy installation and removal of these parts.

- Anyway, cut 5/16ths by 18 threaded rod for 3 pieces of 1-1/4 to 1-1/2 inch lengths. Saw what will be screw driver slot into one end which will become the top of the stud. Dress the ends with a file so they thread into a female threads smoothly having no burrs.

- Clean then dry the cut threads on the oil passage, the studs and 3 of what will be locking/locating nuts very thoroughly to be sure no oily residue is on these parts where assembly needs to take place.

- Apply Locktite to the threads of the holes in the oil passage and on the studs you made. Screw the studs into the holes to where they just meet the inside diameter of the oil passage.

- Apply Locktite to the stud from about 5/16ths above the oil passage casting. Thread a 5/16ths nut down the stud till it lightly contacts the casting. Do this for each stud.

- Torque the nut, to do this do not let the stud turn, this is what the screw driver slot is for. Hold the stud from rotating with a screw driver while torquing the nut to 10 foot pounds. Probably will need a crow food open end in whatever drive size your torque wrench uses.

- Walk away for 8 to 10 hours to let the Locktite cure. The Locktite keeps the parts from vibrating apart and prevents oil seepage past the stud threads in the oil galley casting.

- Final assembly is accomplished by dropping a 5/16ths fender washer (large diameter compared to a standard washer) onto each stud. Drop on the spider then a standard 5/16th washer with a nut. Again you do not want the stud to turn, so restrain it with a screw driver or if you can snake an open end under the spider grab the nut beneath to keep it from rotating, then torque the upper nut to 10 foot pounds, you may use Locktite or a self locking nylock nut to ensure long term security of the fastening.

2) My plan B on these things where I felt better retention of the stud or bolt if you choose that direction (though I think the stud makes this simpler) is to do everything in section 1 except I continue the drill into the oil passage that goes to the cam and finally the main bearings for these 3 in the center. You will see that the already factory drilled oil from the main to the cam bearings continues into the main oil galley hole happens to be right under where you need to drill for the spider studs.

- When I'm nervous about the anchorage of the spider retention studs I've continued the tapping through the upper hole drilled into the top of the oil passage casting and continued for about a half inch into the passage to the cam bearing.

- I add this additional length to the studs when cutting them off.

- I measure for that part of the stud that is exposed inside the main oil passage to where it bottoms in the feed passage to the bearings.

- From the point of entry into the oil passage I cut into the stud 4 grooves that emulate the width of the grooves in a tap, this leaves 4 threaded ridges on the lower part of the stud. This provides oil flow past the stud to feed the cam and main bearings.

- I then measure for the area the stud occupies as it passes through the main oil galley. Then dress the threads off that portion of the stud to provide flow around the stud for oil moving up the main oil galley.

- I'm careful not to put Locktite on the lower portion of the stud where it penetrates into the oil passages as the structural strength of the stud has been compromised in favor of oil flow to a point where trying to back it out against the forces of Locktite in the bottom threads might cause the stud to break in its reduced diameter area which happens to be inside the oil passage. If that were to happen removing the spider will now become removing the engine to get at the broken studs.

- I always combined this method with the installation of a high volume, high pressure oil pump to be sure adequate lubrication to the center cam and main bearings is maintained with the reduced flow area of the modified studs.

What applies in all of these methods is cleanliness. You must be sure that chips are thoroughly washed out and oily residue is eliminated from surfaces where Locktite has to be used. Further you must be careful that reassembly doesn't create chips which means you need to carefully deburr your work. This is the best assurance against trapped, unseen chips is to do this work with cam bearings knocked out.

The YouTube that was attached by "icsamerica" is interesting in that he talks about but does not show a method of putting a bar into the oil passage that is drilled and tapped for the studs and is shaped or drilled for oil passages. I can envision at least a couple ways of doing that but have never used that method myself.

Bogie