Camshaft wear.

Cameronluster said:

What is the 2 18 7135? And the D and 9

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ericnova72 said:

Send it out to a cam regrinder, have them assess it. If they say they can save the cam bearing journal surfaces then use it as the core for a regrind to a better performance match to your application. That will freshen all the lobes up like brand new. Help keep the cost down on the build as well.
It's he best way to go, with all the problems in the camshaft industry at this point in time.
Guys are actually starting to hoard good cores, instead of just tossing them out like the old days for scrap tonnage.


It actually brings a tear to my eye thinking about the buckets of used stock SBC hard faced hydraulic flat tappet lifters that I scrapped off many years ago. Those cores would be like gold today, perfect hard face regrind lifter cores tossed away for scrap steel value. Wish I had those back now.
Nobody foresaw the cam/lifter crapfest coming to the performance industry in time to save it..

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BogiesAnnex1 said:

There are several GM cams that work well with TBI 87-95 and the MPFI 96-02.

- Stock 96 P/N 10241264; no fuel pump lobe; duration 255/266 at zero, 190/195 @ .050 , stem lift for 1.5 rocker .414/.428, ICL 106.25, LSA 111. What you see published can vary a small bit depending on who did the measure or to reflect production tinkering, this applies to any cam.

- Stock 96 P/N 14097395 has fuel pump lobe, timing same as 10241264.

- I’ll sight the Ram Jet P/N 140097395; no fuel pump lobe; 288/[email protected] zero; 196/206 @ .050, stem lift for 1.5 rocker .431/.451; don’t have the ICL and don’t feel like doing the math; LSA 109. This cam is not all that much of a hot rod cam though, the really long ramps and tight LSA give it a rasty sounding idle it can’t back up with performance, the long ramps and tight LSA will not play well with production L03/L05 nor L30/L31 computers.

- A very nice EFI street cam your stock 87-2002 EFI will pick up with an active O2 sensor is the 1987 TPI cam P/N 14093643; no fuel pump lobe; I cant find my detail notes which has the measured zero lift specs but this cam plays nice with TPI, TBI and MPFI from 87-02 engines. At .050 lift it specs 202/206, with the usual 1.5 rocker it only lifts .403/.415 on a wide LSA of 115 degrees. OEM computers pick this cam up very nicely as usual with a working O2 sensor and do it with a 1.6 rocker which improves the meager lift to .430/.442.

- Another cam that works well with 87-02 engines with some sort of factory EFI is the 95-97 LT1 cam part number 12551705. The .050 duration is 201/208; lift is .447/.459; the LSA is 117 degrees which makes this cam super stable with OEM computer programming even with 1.6 rockers

- The original LT4 cam is another candidate but due to its lift might get the OEM computer into a little programming but this is not so crazy that one of those canned performance chips or external processor won’t pick up with an active O2 sensor. Part number 12551142 it specs .050 duration at 203/210 with lift of .446/.450 with 1.5’s and for the daring using a 1.6 .476/.480 inches of lift. This uses a wide LSA of 115 so it holds a pretty high manifold vacuum which Manifold Absolute Pressure managed EFI’s really like.

For flat tappet cams used in EFI engines the stock TBI trucks ran a duration at .050 of 166/175 lift of .382/.402 on an LSA of 112 degrees basically your shop’s broom handle is more aggressive.

The passenger car versions of TBI got a roller cam with a whopping 179/194 with .350/.385 lift still on a 112 LSA.

TBI cop cars got roller cam pretty similar to that grocery getter above with 180/194 and a bit more lift of .392/.401 on that 109 LSA along with a different program and bigger flowing injectors.

As a comparison the old 929/051 cam used in every pedestrian 305/307/327/350/400 from 140 to 300 horsepower timed 256/268 @ zip lift and 195/202 havind lift of .390/.410 and an LSA of 111 degrees. With 10.5 and camel hump heads this cam makes 300 horses in a 327 and repeats that power in a 350 with the same heads but 9.5 compression. This cam works very well with EFI engines lke those I sight from 87 -02 as well as carbed engines.

So as a data point this should give you a pretty good range of cams that work with these non- high performance in a hot rodders sense engines. Most of these are repeated under private labels from most hotrod/racing emporiums. A lot of guys like the Ram Jet cam I not so enthusiastic about it because where you get into these tight LSA cams you really need to Jack up the compression to get as much bite out of them that bark intones should be there and that on modern corner station gas is not easy to do without modern heads starting at the L31 Vortec into the aluminum aftermarket’s.

Any of these cams roller or flat tappet not only play nice with EFI but also carbs. Most of these cams are available in identical copies or very close. The main point I’m emphasizing is that similar cam architecture by other makers will have similar performance to these. I sight the 929/051 cam as that cam with decent factory heads made 300 horses on both the 327 and 350 the former having 10.5 SCR and the latter at 9.5.

Bogie

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BogiesAnnex1 said:

Are you using the EFI or a carb?

Yes this is in the range of the cams I sighted that work well with factory EFI and they also work with a carb.

The .450 lift with a 1.5 rocker should work but it’s at the edge of L31 Vortec heads. Helping you spend your money if you use beehive springs with either Comp’s 787-16 retainer or the kit from Alex’s Parts and I think an outfit called Diablo has one also, these get around machining the top of the guide down. GM says you can run .47 on the lift with these heads but since there should be a minimum of .050 inch between the bottom of the retainer to the top of the stem’s oil seal It pays to measure first than to repair or rebuild again later. The reason for the special spring retainers besides retainer to guide clearance is standard beehive springs are sized in metrics for GM’s switch to 8mm valve stems starting on the Gen III engines. So when you use beehives with the Gen I or II SBC using 11/32 stem diameter valves you have to use these metric to US dimensions retainers so not only is the top of the spying healed properly but the US standard dimension valve locks sit properly so the ID of these retainers is Amenicn measure while the OD is metric. Talk about making being half pregnant possible.

Bogie

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Cameronluster said:

I got a camshaft out of a 1997 350 vortec. Trying to figure out if I should replace it or not. The engine spun a bearing so there are these spots on the cam. You can feel them, but are they bad enough to go ahead and replace the whole cam? Or can you smooth these spots out. View attachment 630146
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BogiesAnnex1 said:

The cam drives the spring.


This is popular with class racers the ubiquitous blue spring.

https://www.jegs.com/i/Chevrolet-Performance/809/19420455/10002/-1

One of my faves for cams like those I recommended if your b going to beef up the studs to 7/16 screw ins and aftermarket rollers especially the heavier stainless types as these will hold the higher RPM’s you can reach when the studs and rockers aren’t flexing.

Howards Cams Electro Polished Beehive Valve Springs, 1.280" O.D., 115 @ 1.800", 354 @ 1.225" - Competition Products

Howards, Electro Polished Inverted Conical Valve SpringsBR Style: Inverted ConicalBR Lower O.D.: 1.280BR Top O.D.: 1.035BR Lower I.D.: .900BR Top I.D.: .650BR Seat Pressure: 108 @ 1.800BR Open Pressure: 345 @ 1.225BR Rate: 412BR Max Lift: .600BR Coil Bind: 1.150BR Steel 7° Retainer: 97161BR...

www.competitionproducts.com

Keep in mind that the factory roller SBC uses a 7..2 some call it 7.3 inch long pushrod not the 7.8 inches used with flat tappets.

Also the L31 Vortec heads use self guiding rockers. A change to not self guiding (pre-1987 production) requires pulling the pressed in rocker studs then milling their bosses down about half an inch. Reassembly requires steel guide plates, hardened push rods and hex base rocker studs. So this is a pretty significant and somewhat costly modification. Basically doing this and other mods on Vortec heads quickly rises to the cost of import aluminum heads. So you need a plan going in so you don’t end up scattering a lot of money.

Bogie

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Cameronluster said:

I’m just going to go with that blue spring sense is best for that cam that I’m going to. Im only even doing that because my stock one is trashed and another stock one with the same specs as mine is about the same price as the one with the 450 lift. So I DEF don’t want to do any modifications required for other Springs.

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BogiesAnnex1 said:

Both use or better stated can use the Comp retainer. I use the term “can use” as there are other retainers on the market. I’m a simple man I try to limit the options to parts I have a history with that have proven themselves reliable when I make recommendations. That’s not necessarily to disparage anybody else’s parts.


Bogie

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