[Tynan918]

If I was choosing a cam, I would stay pretty close to factory specs or just a very small bump up.

What is a "small bump up" from a stock L69 camshaft ?

I just want something bigger than stock without having to mess with stock pushrods, rocker arms, or valve springs.

Then they should be just fine for this. I would guess the heads are original to the motor so if they are H.O........

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Gotcha, when I pull out this camshaft we'll know for sure if it's an H.O. or not. I will also do a roller test with the rods and show you guys some pictures of my rocker arms when I get to that point.

 

[Tynan918]

 

[Moedog07]

@Tynan918

My question to you is do you want a smooth stock idle or a noticeable idle (choppy) from the engine or have you changed your mind?
If you stay somewhere near the original camshaft's specs it will sound "stock". If you want a noticeable idle you will need to use a tighter LSA or more duration or both.

 

[2001Blazer4x4]

@Tynan918

My question to you is do you want a smooth stock idle or a noticeable idle (choppy) from the engine or have you changed your mind?
If you stay somewhere near the original camshaft's specs it will sound "stock". If you want a noticeable idle you will need to use a tighter LSA or more duration or both.

I think he wants it to get him back and forth to work until he can afford a better engine. This 305 is not worth putting significant money into. But he is between a rock and a hard place with transportation. Almost 25% leakdown on some cyl and cost to rebuild a 305 is the same as a 350. New cam is to get him by because it is flat. At least thats how I understand it.

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[Tynan918]

@Tynan918

My question to you is do you want a smooth stock idle or a noticeable idle (choppy) from the engine or have you changed your mind?
If you stay somewhere near the original camshaft's specs it will sound "stock". If you want a noticeable idle you will need to use a tighter LSA or more duration or both.

I want a noticeable idle, but nothing too big. I don't want to have to change my springs or get any longer rods and rocker arms.

 

[Tynan918]

I think he wants it to get him back and forth to work until he can afford a better engine. This 305 is not worth putting significant money into. But he is between a rock and a hard place with transportation. Almost 25% leakdown on some cyl and cost to rebuild a 305 is the same as a 350. New cam is to get him by because it is flat. At least thats how I understand it.

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You remember my leak down test? I don't remember if I shared that here or not...

The motor ran pretty strong, it was just that damn tick, and now that I have inspected the lifters and somewhat of the camshaft lobes, it's considered that I should at least change the camshaft and lifters since I can't afford an engine swap at the moment.

 

[BogiesAnnex1]

A real L69 ran about 9.5:1 compression that’s about .9 ratio higher than the standard 305. Somewhere the L69 cam times at point oh-fifty at 202/206 degrees with lift at the valve of .403/.415 inch with an LSA of 115 degrees. Should idle at 650 revs.

The pedestrian 305 cam times 178/194 with lift at .350/.385 on a 108 LSA it’s idle is 650.

The standard cam is not unlike the timing used for the 87-95 Swirl Port, TBI engines both 305 and 350. This is lower than a the typical GM mild cams which the L69 times like the earlier standard V8 cams.

While we speak of LSA in generalities of tight LSA having the characteristics of lots of overlap and low idle vacuum where a wide LSA is having little overlap and high idle vacuum, in reality you need to calculate a degree scale from this data to figure the actual overlap as that is what really counts in terms of how the cam reacts and sounds.

But either of these cams are mild cams using stock production springs and valve train parts there is nothing amazing going on with the L69 cam. Prior to emissions requirements the L69 cam’s characteristics of timing in the lower zone of 200 degrees and lifts hovering close to .4 inch were standard production cams found in 283’s, 327’s 307’s, 350’s and 400’s. All used the same lifters, push rods and rocker’s.

The L69 cam is no big whoo except when compared to the SMOG heavy LU4 or LO3 engines.

Bogie

 

[2001Blazer4x4]

You remember my leak down test? I don't remember if I shared that here or not...

I think it was in one of your other threads.

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[BogiesAnnex1]

I want a noticeable idle, but nothing too big. I don't want to have to change my springs or get any longer rods and rocker arms.

 

[BogiesAnnex1]

A noticeable idle comes on with an intake duration of 215 degrees and higher. The lopey idle is a function of more overlap and a late closing intake. This is the engineering and physics there ain’t no way around it.

The idle will be barkier with higher compression and less LSA but again LSA is an indication of overlap and but not an actual measure. Somewhat like converter stall speed it’s dependent on other influences not a direct measure of them.

Like Isaid before more than once the L69 cam is no big whoo. It essentially is a grocery getter cam from the presmog days. It isn’t long enough in duration to create the situation of lots of overlap with a late closing intake valve.

Overlap is in the zone n lauding TDC and several degrees before and after where both the exhaust valve is not yet closed and the intake is opening. This is used to have the exiting exhaust to start to pull the intake charge into the cylinder and to use the incoming charge to scour out the remaining exhaust. With a big cam having a lot of overlap at low engine speeds
thus low intake charge inertia there is enough cylinder pressure to vent some exhaust back into the intake system making a weak and exhaust diluted charge that doesn’t burn well so the idle staggers in RPM and sound. This condition is further enhanced at idle by the piston rising on compression and pushing mixture back into the intake further weakening the idle burn and resulting in the engine staggering to try and keep itself running. This is he reason for big cams needing a fast idle, that is to provide a minimum burnable mixture that the engine will idle on. This is the physics and the engineering, every 4 cycle engine is limited by this period!

Bogie

 

[Moedog07]

If you're interested in saving a few dollars check out the Summit Racing brand hydraulic camshaft # SUM-1102. It is Summit's version of the Edelbrock Performer-plus camshaft for a SBC. The specs are very close. That has been a very popular cam grind for several decades. In my experience it runs better than the stock 350 camshaft. Should be noticeable in a 305. No new springs or converter needed. New timing set is strongly advised. Whatever camshaft you use be sure to use quality lifters and break-in oil when breaking in the cam and lifters.

 

[BogiesAnnex1]

If you want a lope you need to get the duration up and the LSA tighter. But your stuck between not wanting spring replacement and probably don’t want to install a higher stall converter.

Unfortunately even the mildest of cams that stagger the idle without getting into pushing a stall converter and not too crazy on duration tend to push the lift. Cams that push the lift quickly get into springs. They also require you check clearances of retainer to top of guide including the stem seal, coil to coil on the spring and getting up around .5 inch lift the valves to piston. It’s pretty hard to get what you want for an idle without going deeper than you want.

Probably the lowest cost answer is the Summit 1103 with 214/224 at .050 lift having total lift of .444/.466 on an LSA of 112. After that Summit 1104 at 224/224 with lift of .466/.466 on a 114 LSA.

The 305 with small valves, ports and bore diameter will be more responsive to duration increases than lift. This is because the flow in CFM is limited by these dimensions, therefore, the answer is to buy more time which is what duration does.

Three other big helps but require digging deeper than it appears you want to is to back cut the valves, run 1.6 rockers and pocket port the heads. This really helps the 305.

Back cutting behind the valve’s about 30 degrees to blend the seat with the back side of the valve head shape into its seat angle seat really increases low to mid lift flow from just off the seat to about .4 inch. But you gotta take the heads off or this surgery.

Your kind of between a rock and a hard place trying to keep the old motor running and wanting a raspy idle while setting funds aside for a replacement motor. OK technically an engine.

Bogie

 

[Moosecountry]

You need to go back and read all the posts not just some of them

 

[Tynan918]

If you're interested in saving a few dollars check out the Summit Racing brand hydraulic camshaft # SUM-1102. It is Summit's version of the Edelbrock Performer-plus camshaft for a SBC.

Probably the lowest cost answer is the Summit 1103 with 214/224 at .050 lift having total lift of .444/.466 on an LSA of 112. After that Summit 1104 at 224/224 with lift of .466/.466 on a 114 LSA.

Someone else local was mentioning using the Summit 1103 in his 383 and sent me a video of his engine running so I could hear the sound of it...

Sounded good and choppy, but he also has open headers I believe.

 

[Tynan918]

After that Summit 1104 at 224/224 with lift of .466/.466 on a 114 LSA.

So this Summit 1104 is as big as it gets with my options in specifications without changing anything else like rods, rocker arms, valve springs, and my 1350 stall ?

 

[Tynan918]

So this Summit 1104 is as big as it gets with my options in specifications without changing anything else like rods, rocker arms, valve springs, and my 1350 stall ?

So the Summit requires a 2,000 stall converter...

 

[Tynan918]

The Summit 1103 is a good choice but won't be shipped out to me until January 11th, 2023...

 

[Tynan918]

I really got my eye on this Comp Cams CCA-12-206-2...

What do you guys think about this one ?

 

[2001Blazer4x4]

Just keep in mind that for a given camshaft, how it acts in a small 305 is much different than in a much larger 383 - so generic statements about torque converter and gears are suspect and do not necessarily correlate with reality. The same cam will act more radical in the smaller engine.

Take a look at the Crower catalog. Not saying you want one of their cams - but they do account for engine size and these same rules apply to all manufacturers.

 

[Moedog07]

The cams listed above by the OP are getting into the lift and duration numbers of GM's L-79 and L-82 camshafts.