[eric32]

Hello guys just got a used 96 chevy s10 with a 350 vortec in it and don't know if its got a roller cam or flat tappet cam in it. Don't know where to look for the block casting number to tell what it is. I was thinking of just putting a new cam and lifters in it to help to give it a little more pep. Then maybe next spring a new set of vortec heads. What ever is in it now is just pretty much bone stock. If it is a flat tappet cam it kind or worries me cause with the oil no longer having good amounts of zddp in it to help with the lobes not getting wiped out. I have read that many people on here have had comp xe cams go bad and that was I was looking at or a summitracing cam and lifter set. The local auto part stores don't stock zddp additive and that is kind of a hassle to have to order some online and pay shipping and such. I don't know if the block is a two piece or one piece seal with the oem roller setup. If thats the case I will just get a new set of roller lifters and a new roller cam with a littler more umph to put me around 300hp. Any one using the old flat tappet cams anymore ok?
Thanks
Eric

[ScoTFrenzel]

Originally Posted by eric32

Hello guys just got a used 96 chevy s10 with a 350 vortec in it and don't know if its got a roller cam or flat tappet cam in it. Don't know where to look for the block casting number to tell what it is. I was thinking of just putting a new cam and lifters in it to help to give it a little more pep. Then maybe next spring a new set of vortec heads. What ever is in it now is just pretty much bone stock. If it is a flat tappet cam it kind or worries me cause with the oil no longer having good amounts of zddp in it to help with the lobes not getting wiped out. I have read that many people on here have had comp xe cams go bad and that was I was looking at or a summitracing cam and lifter set. The local auto part stores don't stock zddp additive and that is kind of a hassle to have to order some online and pay shipping and such. I don't know if the block is a two piece or one piece seal with the oem roller setup. If thats the case I will just get a new set of roller lifters and a new roller cam with a littler more umph to put me around 300hp. Any one using the old flat tappet cams anymore ok?
Thanks
Eric

Problems with flat tappet cams going bad is an ENGINE ASSEMBLER/ BREAK-IN problem.
Don't blame a cam manufacturer.

I bet that most of the cams sold today are flat tappet cams.

[04SilveradoMykk]

To answer your question... the 96+ Vortec 350's had roller cams.

You can use a flat tappet cam, but you'll need lifters (obviously, usually replaced anyways) and longer pushrods and ditch the cam retaining plate on the front of the block.

The engine I'm building had a flat tappet cam in it, and it's a 4 bolt main, one piece rear, roller cam block. I am pro-roller motors and am using roller valvetrain now.

[automotive breath]

I've been using solid flat tappet cams for about thirty years now. People started
complaining about wiping lobes about the time when one of the largest lifter
manufactures went out of business. The quality of lifters went down, only one
or two top manufactures are left in business. Some people say its the oil, I say
its the lifters.

I buy all of my flat tappet lifers from Isky, they don't manufacture lifters,
however the quality is there and I never wipe a lobe. Some of the major cam
manufactures sell junk lifters, you will know if you buy then, you will be changing
a lot of cams.

[ScoTFrenzel]

AB
is there still a lifter problem? that you know about currently.

I agree, I most always use a top of the line lifter.
How about the lifters with the oil hole in the face? used any?

[machine shop tom]

It's getting to be a real crapshoot. I just had a guy lose a cam this week and he did everything to not have it happen.

tom

[automotive breath]

Hi ScoT,
I can buy Chevy solid lifters for $120 or $39. I don't know that there's any
difference between the two but I would bet there is. With everything coming
from offshore, do we know the quality of anything anymore?

One thing for sure, if the taper isn't ground correctly on the lifter face, you will
lose a lobe or two in a heartbeat. To make things worse, cams can be ground
with very aggressive ramps requiring high spring pressure to keep everything
together. With a flat tappet I avoid both.

As for the oil fed lifters, I haven't tried them, it sounds like a good idea. I do
keep the oil pressure up and avoid extensive idling.

Tom,
Do you know the details of the build that lost the lobe. Radical cam? What
brand lifters?

[Lonestar]

I personally have never seen the need for anything more than the flats for street use. I do agree with quality issues as mentioned above though... Luckily there is a company here by me that I can just give my desired specs to and they grind me a top quality piece.

In your application I would probably go with a roller simply because that is what the engine was designed for. You can modify for a flat but unless you know what your doing you may do more harm then good.

[Double_v23]

I agree with the crapshoot,

You can calculate every angle, check every clearance, use the right springs, lifters, and cam for your application, degree the cam, use the isky rev lube, break it in with Brad Penn "green" break in oil....

And still have problems.

The only way to know for sure is to use a roller. The direct oiling solid lifters seem to help a little but they aren't used on hydraulics.

[oldbogie]

Originally Posted by eric32

Hello guys just got a used 96 chevy s10 with a 350 vortec in it and don't know if its got a roller cam or flat tappet cam in it. Don't know where to look for the block casting number to tell what it is. I was thinking of just putting a new cam and lifters in it to help to give it a little more pep. Then maybe next spring a new set of vortec heads. What ever is in it now is just pretty much bone stock. If it is a flat tappet cam it kind or worries me cause with the oil no longer having good amounts of zddp in it to help with the lobes not getting wiped out. I have read that many people on here have had comp xe cams go bad and that was I was looking at or a summitracing cam and lifter set. The local auto part stores don't stock zddp additive and that is kind of a hassle to have to order some online and pay shipping and such. I don't know if the block is a two piece or one piece seal with the oem roller setup. If thats the case I will just get a new set of roller lifters and a new roller cam with a littler more umph to put me around 300hp. Any one using the old flat tappet cams anymore ok?
Thanks
Eric

Chevrolet had problems with their flat tappet cams from the git-go. They found themselves on the receiving end of several class action suits on the subject. So given that as a starting premise, adding to it the changes in EP ingredients of oil since the mid 1980s, the risk to flat tappet and lobe failure is only larger since then. However, high quality flat tappet cam manufacturers have been compensating with better base materials and surface hardening treatments.

But I've long held that the hand writing was on the wall for all to see. When the OEMs switched to roller cams, that was clear notice to all concerned that they felt that flat tappet designs lacked the necessary long term durability with these new oil's that were EPA restricted in the use of metallic dry EP lubes within the oil's additive package.

I think you need to find out whether or not your block has or is equipped to have a roller before you start spending money. First place to look is the block casting number, this will tell you if it's a roller prepped block or not. Look for these casting numbers to identify a 350 roller block 10243880, 14011148, 14088526, and 14093638. Be careful of 14011148 as there is a close number 14101148 which is a flat tappet block.

Having one of those numbers means the block has the provisions for a roller cam, however, this doesn't mean it has a roller cam as these blocks will accept a flat tappet cam and the factory kept some usage of them in truck engines thru 1995. Remove a rocker cover and shine a bright light into the valley, if you can see the tops of the lifters and they have a guide that attaches them in pairs you're looking at a roller. If you can't see in there, the next check is push rod length. Back off a rocker that's sitting with the valve closed as you'll have to readjust the lash when you're done. Remove the pushrod to measure it; the OEM roller pushrod length is 7.195 inch for the taller roller tappet; the OEM flat tappet pushrod length is 7.795 inch.

If you have a roller, I'd certainly not consider going back to a flat tappet. If you have a roller block with a flat tappet, I'd convert the thing to take advantage of the OEM roller, parts to do this can be had from GM or the aftermarket. If this is a flat tappet, I'd recommend that you include a cam button to take the thrust load off the tappet/lobe interface this will help these guys survive in a world of reduced EP additives. Also, follow the cam manufacturer's break in procedure to the letter.

Bogie

[k-star]

Since the big lifter deal that hit almost every engine builder, I check the crown of every flat tappet lifter I install. Back when all this was going on I would find 1 or 2 lifters per set that only had .001 or less crown ground on them. My tolerance was: if the lifter had less then .0015” I would not run it. I never lost one single flat tappet cam since I started doing that. Now that required me to have at least one broken set laying around to pick extras from. The correct crown is .0022”

During that time I was building 358 limited late engines that had to be flat tappet cams not rollers. They were some very aggressive lobes on those cams. I had zero issues with them also. But I followed my procedure to a “T”

I have an entire song and dance I go through with a flat tappet engines when I build them., It’s a bunch of extra work.

For me personally I will do what ever I can to talk the customer into going roller. There is almost a zero chance of having a problem with them, that means no come backs… There are a lot of shops that will not build flat tappet engines any more.

I explain the deal to the customer and let them know I have zero responsibility if the cam eats a lobe, and that the engine will need completely torn down and cleaned if it does, on there dime…I let them make the choice.

So, the choice is yours. The flat tappet cams work, but for the average guy the peace of mind that comes with installing a roller is worth the little bit of extra $$$ spent up front. As a reminder, if the cam fails the money to R&R the engine is more then the extra money needed to go with a roller…

I built 10 engines this year, 8 were roller, 2 flat tappets.

Keith

[machine shop tom]

Originally Posted by ScoTFrenzel

Problems with flat tappet cams going bad is an ENGINE ASSEMBLER/ BREAK-IN problem.
Don't blame a cam manufacturer.

Bull poop!

tom

[CNC BLOCKS NE]

Originally Posted by ScoTFrenzel

Problems with flat tappet cams going bad is an ENGINE ASSEMBLER/ BREAK-IN problem.
Don't blame a cam manufacturer.

I bet that most of the cams sold today are flat tappet cams.

In the last month we have seen two VOODO cams in the shop low milage one was a solid flat tappet and the other was a hyd. flat tappet low miles on both and they were done on Crane cores, I think the core number was 986 and I tild them P-55 cores are a performanc core and are harder.

They called Lunati and they don't even offer P-55 cores so both called Tim at Bullet cams and got the P-55 cores.

We use alot of flat tappet cams with no problems hyd. lifter we buy them right from GM and soid lifter we buy the tool steel lifter and no problems.

And we have our cutomers use the reccomended oil and cam break in is important with proper springs or break in rockers.

[red65mustang]

all 16 lobes receive the same induction or flame hardening Rockwell finish at once so all the lobes would/should go flat if the cam is at fault.....
the Crane Cams site states that they have yet to get a flattened lobe cam back with less than 55(?) Rockwell hardness finish....

there are millions(?) of assorted "stock" flat tappet motors (lawn mowers/generators/inboards/fork lifts/whatever) sold every year and they don't have a wiped out lobe problem.....(even using today's oil and lower Rockwell finish)

the single lobe failure problem source is very probably not the camshaft itself

[CNC BLOCKS NE]

Originally Posted by red65mustang

all 16 lobes receive the same induction or flame hardening Rockwell finish at once so all the lobes would/should go flat if the cam is at fault.....
the Crane Cams site states that they have yet to get a flattened lobe cam back with less than 55(?) Rockwell hardness finish....

there are millions(?) of assorted "stock" flat tappet motors (lawn mowers/generators/inboards/fork lifts/whatever) sold every year and they don't have a wiped out lobe problem.....(even using today's oil and lower Rockwell finish)

the single lobe failure problem source is very probably not the camshaft itself

On the flat tappet cam 80% of the lobes showed wear at the nose and 2 lobes were starting to pit.

This cam had 360 over the nose and 140 at the seat.

We have P-55 cores with 430 over the nose and 170 at the seat and no issues.