Duntov “097” vs 30-30 Camshaft

[saopm]

Well I’ll have the motor out tomorrow, and will have to decide what exactly I want to do with it. I might change the cam. I assume I have the Duntov 097 cam but I am not sure. When I have the cam out how will I know what it is? Are there numbers on it or will I have to have the profile measured? What are the differences between the Duntov 097 and the 30-30 in terms of performance, idle, and sound? Also if anyone has the specs (lift and duration) of the both cams I would appreciate it.

Would this be the modern 30-30? http://www.powerandperformancenews.com/store/merchant.mvc?Screen=PROD&Product_Code=CL12-673-4&Store_Code=CC

My current setup is basically a ’63 340HP motor with a ’64 300HP carb. I plan to buy a new performer carb for now. Maybe buy the correct carb if I come across it. How will this setup respond with a 30-30?

Tim

 

[jims427400]

I don't know anything about cams but I do like how everything else matches your car ie. sandblaster and engine lift..
Good luck Jim

 

[JohnZ]

If it still has the original "097" Duntov, you'll see a casting number cast into the cam (3736098 or just 6098) - that positively identifies it, as that casting core was used only for the "097" Duntov cam.

The "30-30" isn't a great choice as a replacement - they make great power above 4000 rpm, but they leave LOTS of torque on the table below that, which is where you do 99% of your driving.

A FAR better choice is the Chevy LT-1 solid-lifter cam; it makes about 20% more low-end torque than the "30-30", gives up very little above 6000 rpm, and still works with the bulletproof stock valvetrain. It's available from GM under P/N 12364054 (kit with lifters) for less than $150, and from Federal-Mogul/Speed-Pro as a kit under their #KC-1145R.

Good street engines are all about torque in the range where you drive them most of the time, and that's where the "30-30" falls flat.

 

[brumbach]

If it still has the original "097" Duntov, you'll see a casting number cast into the cam (3736098 or just 6098) - that positively identifies it, as that casting core was used only for the "097" Duntov cam.

The "30-30" isn't a great choice as a replacement - they make great power above 4000 rpm, but they leave LOTS of torque on the table below that, which is where you do 99% of your driving.

A FAR better choice is the Chevy LT-1 solid-lifter cam; it makes about 20% more low-end torque than the "30-30", gives up very little above 6000 rpm, and still works with the bulletproof stock valvetrain. It's available from GM under P/N 12364054 (kit with lifters) for less than $150, and from Federal-Mogul/Speed-Pro as a kit under their #KC-1145R.

Good street engines are all about torque in the range where you drive them most of the time, and that's where the "30-30" falls flat.

I certainly don't know anything about cams either but would be interested in your opinion onthe 12364050 gm cam or Jeg's 270-968711 which is supposed to be for the 327/350 hp. I'm aware that this is a hydraulic and not solid. Would you recommend the LT-1 over this too and why? I'm interested because I'm just beginning a very long project of building a correct engine for my 65. Thanks -- Bill

 

[saopm]

John, thanks for your response.

I’m still considering cams. I would like to get a complete matched kit that would include camshaft, lifters, valve springs, and timing chain and gear. I found a Compcam setup, but I still want to call to make sure it is suitable for my application. The motor is now out but I need to break it down. Hopefully I’ll get to it tomorrow. As you can see for the pic below the valve stem needs to be replaced. I’m guessing I will have a local machine shop replace the valve and install the new springs I anticipate getting with the cam kit. Maybe replace the guides if needed.

http://www.powerandperformancenews.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=12-675-4&Category_Code=12-CAM

A little leaky on the backside. I don’t think the oil is coming from the rear main anymore. Whoever did the final assembly on this motor failed.

 

[Tom Bryant]

Tim,
d

We all like to keep our cars original, but as far as I know, the NCRS has not as yet, started to judge the cams in our engines

Stepinwolf

Well, as a matter of fact, they do in a way. I have read on the NCRS Tech Board about judging deductions for solid lifter engines that have no solid lifter clatter because they now have a performance hydraulic cam in them. Also for engines with obviously more radical than original cams based on exhaust sound or even a L79 that has a 300 cam in it with no lope.

In other words if it's a 327/340 it needs to sound close to what a 327/340 should sound like including the clatter of solids. I'll bet that a Master Judge like John could tell a LT1 from a 097 on a judging field by listening to the exhaust. Expecially with so many other correct ones there to compare with.

Tom

 

[stepinwolf]

Now that you mention it.

Well, as a matter of fact, they do in a way. I have read on the NCRS Tech Board about judging deductions for solid lifter engines that have no solid lifter clatter because they now have a performance hydraulic cam in them. Also for engines with obviously more radical than original cams based on exhaust sound or even a L79 that has a 300 cam in it with no lope.

In other words if it's a 327/340 it needs to sound close to what a 327/340 should sound like including the clatter of solids. I'll bet that a Master Judge like John could tell a LT1 from a 097 on a judging field by listening to the exhaust. Especially with so many other correct ones there to compare with.

Tom

You know Tom,

Now that you mention it, I do recall having read something to that effect in their ( NCRS ) reference manual. That being said, I would like it to be known that I do not intend to, nor will I EVER, put any one of my cars through the judging process.

I have been asked, and have served, as a NCRS judge on more then one occasion, and don't really need someone to tell me what they think ( opinions are just that ) is wrong with my car. I do not object to anyone who wishes to do so, but as far as I'm concerned, it is not the type of gratification, or satisfaction, that I need to be able to enjoy my ride.

As we are on the " Cam " thread, there is something else that comes to mind regarding my choice of cams, that is also worth a few lines. A few years ago I participated in a Show & Shine that happens to be the largest show in this Province. The process they use to go over a car is rather elaborate, and part of it needs to have the car running, in order to verify certain aspects of the engine.

Well there must have been a new judge in the team, because when all was said and done, he came over to me and whispered in my ear that I might want to think about having a tune-up done to my engine because according to him, the engine seemed to be running ( because of my VERY lopy cam ) rather erratically.

I realize that he was not a NCRS judge, but this was the very last time that anyone with any judging intentions ( except to win the Super Chevy Show in Epping ) was permitted to approach my ride.

For those of you who have seen " Forrest Gump " I will end with a quote from the film " and that's all I have to say about that "

Stepinwolf

 

[BarryK]

Well there must have been a new judge in the team, because when all was said and done, he came over to me and whispered in my ear that I might want to think about having a tune-up done to my engine because according to him, the engine seemed to be running ( because of my VERY lopy cam ) rather erratically.

besides being pretty pathetic, it's actually pretty funny!

you know Bob, I have what I believe is the stock 30-30 cam in my L76. I believe it's stock simply because of the driving characteristics and the powerband matches what everyone says the 30-30 is like. the downside is as John mentioned the low-end torgue sucks.
I've strongly considered swapping out to the LT-1 cam that John and Duke always recommend but one thing, and one thing only makes me hesitate..... I LOVE the lopey idle that my car has. It just sounds awesome to me (not as good as a BB but still really nice as far as a SB motor goes I think), especially going thru the side pipes.

Now, if I could find a cam that increases my low-end torque AND still has that nice lopey sound to it I'd proably make the swap.

 

[stepinwolf]

besides being pretty pathetic, it's actually pretty funny!

you know Bob, I have what I believe is the stock 30-30 cam in my L76. I believe it's stock simply because of the driving characteristics and the powerband matches what everyone says the 30-30 is like. the downside is as John mentioned the low-end torque sucks.
I've strongly considered swapping out to the LT-1 cam that John and Duke always recommend but one thing, and one thing only makes me hesitate..... I LOVE the lopey idle that my car has. It just sounds awesome to me (not as good as a BB but still really nice as far as a SB motor goes I think), especially going Through the side pipes.

Now, if I could find a cam that increases my low-end torque AND still has that nice lopey sound to it I'd probably make the swap.

Barry,

Call Comp-Cams, explain EXACTLY the characteristics you are looking for, and they will recommend the cam that you need.

Stepinwolf

 

[BarryK]

I very well may just have to do that in the not too distant future

 

[JohnZ]

I certainly don't know anything about cams either but would be interested in your opinion onthe 12364050 gm cam or Jeg's 270-968711 which is supposed to be for the 327/350 hp. I'm aware that this is a hydraulic and not solid. Would you recommend the LT-1 over this too and why? I'm interested because I'm just beginning a very long project of building a correct engine for my 65. Thanks -- Bill

The 4050 kit (cam and lifters) is a blueprint duplicate of the original L-79 cam, made for GM by Crane (they make all the GMPP cams); probably the best all-around performance hydraulic cam GM ever made. The LT-1 is a solid-lifter cam, has a little less low-end torque, and more top end than the L-79 hydraulic. Both use the same stock GM springs. Either one will serve you well, and will be trouble-free; just depends whether you want solids or a maintenance-free hydraulic.

 

[JohnZ]

John, thanks for your response.

I’m still considering cams. I would like to get a complete matched kit that would include camshaft, lifters, valve springs, and timing chain and gear. I found a Compcam setup, but I still want to call to make sure it is suitable for my application.

That cam has considerably less duration than the LT-1, and about the same as the "097" Duntov, and MUCH more lift than the "097" and just a little more than the LT-1; that says its flank acceleration is quite a bit higher, and it requires stiffer springs to handle it.

The beauty of the Chevy factory cams is that they ALL use the exact same springs as Grandma's 307 grocery-getter (which is quite a tribute to their cam design skills and knowledge of valvetrain dynamics), so they're reliable, bulletproof, and you don't hear all the "wiped lobes" stories that are so prevalent with many aftermarket cams that need Godzilla springs to overcome their harmonics. The stock GM springs are P/N 3911068; 80# closed, 200# open @ 1.25". "Matching" is simple - any factory cam, one spring.

 

[speedmaster4]

3736097/8 lash.012/.018 duration287/283 lift.381/.380 (mk-1 duntov)

3849346 lash.030/.030 duration313/313 lift.447/.447 (30-30 or mk-2 duntov)

 

[saopm]

Well, I got the cam out of my motor last night. It turns out it is a Crane Fireball 296. So I call Crane to find the specs. Crane told me that it is a Hydraulic cam with 233 duration and 0.449 lift. I am not surprised by the miss match of Hydraulic cam and solid lifters given some of the other handy work I’ve seen on the car.

My assumption is that the motor was rebuilt with a hydraulic setup missing the original intake and possibly the original oil pan. When the correct parts were sourced a few short cuts were taken. Instead of removing the cam and replacing it with a solid, someone installed solid lifters only and sealed it up with the period correct components.

The good thing is that the bottom end has very little ware if any. No ridgeline on the cylinders, and the cam looked like it was barely broken in. Tomorrow I am going to bring the heads down to the machine shop to fix the broken valve and replace the springs. I called CompCams to get their advice on a new cam. They suggested the following:
RPM Range 1300-5700
http://www.powerandperformancenews.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=12-675-4&Category_Code=12-CAM

I think I am going to go with the next one up. RPM range 1600-6000
http://www.powerandperformancenews.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=12-676-4&Category_Code=12-CAM

It seems to have the balance I am looking for between performance and drivability. When I bring the heads down to the machine shop tomorrow I get their opinion too.

 

[Kid_Again]

saopm....essentially the same problem i had with my engine, a reputed "correct 365hp" engine with solid lifters running over hydraulic cam lobes....oh, it clattered all right! The only "correct" part of the engine was the 365hp decals on the valve covers. I just listened patiently to the sellers' BS about the engine, noting all the while that I was buying a '65 with a valve cover with the casting crack plainly evident. Whatever.

As a point of reference for me (I don't know the specs on the 340hp), did that engine orginally come with domed pistons?

 

[Fuelie]

Hi Kid,

Yes, the 340hp engines had the factory 11:1 domed pistons

Take care,
Brian

 

[saopm]

As usual, it will cost more and take longer than I expected

I brought my heads down to the machine shop the other day to be redone. The machinist called me back after he disassembled the heads to let me know there was a lot of oil behind the intake valves meaning there was a lot of blow-by. He advised me to take a piston out and check the rings, more or less a might as well type of thing. So I took one of the pistons out and noticed the rod bearing had excessive wear (showing copper). Then one piston lead to another and the complete engine was disassembled. At this point I figured I would take the Block, Crank, and Pistons and Rods down to the machinist to have a look-over and to have reassembled with the correct bearings. Well good thing I did. The machinist said the motor wouldn’t have lasted another 1k miles with the bearings it had in it. To make a long story short the valve job turned into a complete rebuild. As usual over budget, but at least I’ll have a fresh motor with no worries.

I finally decided to go with the following camshaft as advised by the machinist:
http://www.powerandperformancenews.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=12-675-4&Category_Code=12-CAM

I might stick with the flattop pistons to keep the compression manageable. The motor was bored 60 over so that would increase the compression anyway. I’ll discuss this with the machinist when he lets me know what is good and what is bad.

 

[speedmaster4]

oil on backside of "intake" valve is NOT blow-by...blow-by comes with worn piston rings and coats the face (combustion chamber side) of the valve and the piston top and the chamber with black goo...worn valve guides and/or seals let oil run down valve stem to backside of valve where high (normal) temp bakes volatiles out leaving rock-hard build-up

rod/main bearings are steel with very thin electroplate overlay of copper and then aluminum...a bearing worn thru the alum layer to show copper is generally considered "worn out" but would probably go many THOUSANDS of miles...most used engines that i have disassembled to 'refresh' show copper

i dont like people that use "scare" tactics.."con" job usually follows...i'd find another machine shop

 

[saopm]

I don’t think the machinist was using scare tactics but trying to advise me that I’ve come this far, might as well have piece of mind and check the rest of the motor before I put everything back together. He also said the guides were good and the heads were redone recently. The head did have a problem with the exhaust valve (bottom left exhaust valve in pic below) to start. The machinist said it could be blow-by but advised me to take a piston out just to make sure. I assumed it was blow-by, but it could be just the bad exhaust valve. I took the 1k mile comment with a grain of salt and basically assume the ware was significant and could pose a long term problem. I figure I intend to have the car for a long time to come and my original instinct was to redo the whole motor so based on what I saw on the bearings, why not do the job right. My experience with bearing inspection is limited but when I saw wear only on the cap side, it looked odd to me. I assume bearings should wear more uniformly or at list show the most wear on the piston side of the bearing. Maybe someone can expand.

Basically the machine shop is going to clean the block, hone the cylinders, check the mains, and reinstall the rotating assembly. This is in addition to cleaning the heads and installing the springs that correspond to the cam I am installing. I am going to do the final assembly of the heads and valve train myself.

I will definitely take everyone’s comments as good education so I can speak intelligently with the machinist and try not to get ripped off. After all this is as much a learning experience as it is a rebuild.

 

[speedmaster4]

ok-you have -461 castings w/ 2.02 (intake) valves--great heads but they need hardened exh seats added (you can see em if they've already been done but i cant tell from pic) or use lead substitue added to gas...three cylinders (holes) are running rich(dry black coating)...second hole from top on leftside(pic) is using a little oil (shiny black)...bottom left hole intake valve (big ones are intake,small are exh) is unusual-maybe 'starting spray', water ingested, crankcase vent into air cleaner 'favoring' that hole,worn cam,etc-forget about it but watch spark plugs color after rebuild for replay. check cam lobes on oily hole-esp worn intake will suck oil, your worn rod bearings may be spraying more oil than rings can control--dont get too excited about it - rebuild should fix whatever anyway

bearing wear you mentioned could be oil too thick(50w), hi rpms, but most likely 'big' end of rod needs to be 'resized' cuz its not perfectly round anymore--some shops can do em without pressing wrist pins out--pushing pins from used pistons is hard to do without deforming piston...new ARP rod bolts (no jap substitute) while resizing big ends

IMPORTANT-you MUST use "head bolt washers" on the short (lower) bolts when installing these heads...highly prone to breaking the end bolt boss if washers are not added--no fix once they break...the long (upper) head bolts dont need washers and i prefer the tiny extra thread engaged by not using the washer....sealer reqd on head bolts

the ONLY rod/main bearings to use are "clevite 77" unless you never change oil--then use softer "dirt-eaters"

a good rebuilt engine is better than a brand new one