Maximum lift?

['64 Cuda]

Can somebody give me a ball park figure for the maximum valve lift a stock J head will handle before you need to cut down the guides? I seem to remember reading way back that it was around .510", but I'm old, so my brain doesn't work as good as it used to. :sad1: How much clearance is required between the top of the guide/valve stem seal to be safe?

Another question. Does anyone know the proper name, or a part number, for the "spider" on roller cam engines? I've tried searching Mancini's site but can't find it. I found the tappet alignment yokes & the lifters, but no spider.

 

[djwhog]

Can somebody give me a ball park figure for the maximum valve lift a stock J head will handle before you need to cut down the guides? I seem to remember reading way back that it was around .510", but I'm old, so my brain doesn't work as good as it used to. :sad1: How much clearance is required between the top of the guide/valve stem seal to be safe?

I think I have built up to the .540 range and that is close. i think you are correct i read .510-.520 for stock guides, and you need at least .050 for float too.

 

['64 Cuda]

Thanks for the quick reply. Do you know if you can get by with the umbrella type valve stem seals with that much lift?

 

[djwhog]

Thanks for the quick reply. Do you know if you can get by with the umbrella type valve stem seals with that much lift?

I would spend a few bucks and have a nice set of bronze guids installed and the good locking seals. The felpro kit seals are not very good. But on a buget yes they should be OK.

On my heads I also had the spring seats machined and then put in spring cups to hold the springs in place better. This also gives a more even and firmer surface to have the spring sitting on.

All this is done at the installed height reccomended by your cam/sring/valve combination.


PS if you are after a little more HP and going with new valves, then when you get the guides go with the 11/32 guides and slimer 11/32 valves(chevy type). This is only if you are putting a lot of $$$s in the heads.

 

['64 Cuda]

Thanks for all the info. With a new set of springs & seals the heads could be used as they are. But, the valve job that was done on them 30 years ago (they haven't been used since) probably included knurled guides & I know there's much more sophisticated equipment for grinding the seats these days. Plus, they don't have hardened seats. I've been looking at a couple of roller cam profiles that have in the range of .531 to .538 lift, so I'll probably just bite the bullet & have the guides replaced & cut down, etc.

 

[moper]

I think it will be the springs that will require you to alter the guides and spring seats. Today's fast rate profiles use a lot more spring pressures, so you end up having to machine for double springs, which means bigger spring pocket, and smaller guides. You are really giving up a lot of mileage and performance by relying on 40 year old technology for machining.

 

[djwhog]

I agree with Moper, that is why I did spring seats. I needed smaller guides and tripple springs with my solid cam. Todays profiles as mostly faster on the ramps which require stiffer & quicker springs. The advantage of the newer cams is that they loose less bottom end and have wider power bands when compared to a similar early grind.

This is one main are not to skimp on.

 

['64 Cuda]

Another question. Does anyone know the proper name, or a part number, for the "spider" on roller cam engines? I've tried searching Mancini's site but can't find it. I found the tappet alignment yokes & the lifters, but no spider.

I might have found the name of the part. It's an "Alignment Yoke Retainer" or maybe a "Lifter Guide Retainer." Depends on what Mopar book you want to believe. Still havent found a part number. Can't find anything listed except for the V10!

Another question about the heads. If i go ahead & do the hardened seats, new valve job, guides, etc, will it be worth it to blend the bowls & smooth out the ports if I'm going to run the 340 exhaust manifolds? Or are they too restrictive to bother?

 

[djwhog]

well if you:

"PS if you are after a little more HP and going with new valves, then when you get the guides go with the 11/32 guides and slimer 11/32 valves(chevy type). This is only if you are putting a lot of $$$s in the heads"

So if you go with performance 2.02 intake 1.625 ex. then do seats, port work etc. you might be about up to the same cost as you would spend for Edlebrock heads?

For me I have access to a machine shop and 30+ years of experiance so I was able to save the labor but I still spent about $600 on my heads not counting springs, retainers and locks. I am close to a grand. Even so I wanted to see how she will run, some day I may go aftermarket on the heads.

But you need to figure out what the cost for the heads work and how much you want out of the engine?

Back to your last question, yes with some decent port and bowl work from a person that know what they are doing you can gain a decent amount. Then you nee to make sure cam, intake, exhaust etc are all matched for the work performed and determine what RPM level it is best suited for?

On the street it may hurt your low end 2-4k rpm levels some, so just a heads up.

 

['64 Cuda]

With my current block set up as it is & my J heads I will have a static compression ratio of about 9.6 to 1 with a .054" thick head gasket. Somebody here mentioned that a .054" head gasket is available, but I haven't tried to locate one yet. I think Cometic even has a .077" gasket. With the Edelbrock heads & the same gasket it would be about 10.7, or with a readily available .030" thick gasket it would be almost 11 to 1. I know aluminum heads will allow a higher CR, but 11 to 1 is pushing it for pump gas isn't it? I passed up a faily good deal on some Edelbrock heads because of the high CR.

I was also wondering if maybe I should just bolt on the heads as they are (no more machine work) because of the lower flow of the 340 manifolds. This is just going to be a street/play car, so the Edelbrocks seem like overkill, and so does pouring a lot of money into the stock heads. The car will likely never see a drag strip. I don't even know where the nearest track is.

 

[66dartgt]

With the stock style performance single springs w/ dampers the max lift is about .500" from what I recall.

For a street engine that should be enough spring, w/ a reasonable perf hyd cam. I'd take your heads apart clean and inspect them and reassemble them with new seals and run them. You can always play with another set of heads at a different time.

My.02.

 

['64 Cuda]

OK guys, I need some advice here. Quick rundown on my engine. 360 bored .030", J heads w/ 1.88 intakes, approximately 9.6 to 1 compression ratio. Stock 68 to 70 340 exhaust manifolds w/2.5" exhaust. Six pack manifold & carbs with a scoop sealed to the air cleaner. 4 speed (my choice of either a close ratio or an OD), with 3.91 gears. Street driven "play" car.

I've been offered a good deal here on FABO on a custom ground Comp Cams roller cam with lifters, dogbones, spider, etc. Here's the specs.

230/236*@50 110CL 4* advanced w/510/520 vlift (1.5 rockers)

I compared this with the cams in Comps catalog & it's close to an XR280HR-10. I had been looking at the next two smaller profiles in the same line. I had also looked at the Comp "Thumpr" cam with these specs.

Dur @ .050 .227/.241 .513/.498 LSA 107*

The guy with the roller cam also has a Hughes hydraulic cam with matched lifters that is about 2 steps above the 1928AL & 2328AL flat tappet & 1828AL & 2228AL roller cams that Hughes recommended. It has these specs.

230/237*@.050 with 515/535 vlift 110cl 4*advanced.

Do any of these sound suitable for my build? My main concern with them is that they might be a bit much as far as duration. People are always warning about over-camming an engine. These two cams are both very good deals, but I don't want to get the wrong thing just because it was cheap. Plus, the flat tappet is probably a bit better suited than the roller, but I kinda' had my heart set on a roller. AAARRRRGH! I hate trying to pick a cam. :cussing:

Help, please!


:burnout:

 

[66dartgt]

you didnt say what year 360. Assuming the roller cam is hydraulic - If your block doesnt have the provision for the factory hydraulic roller lifters you can toss that out as an option. Mechanical roller cams need alot of attention in terms of valve lash adjustments. In my opinion you need something alot smaller depending on what you expect. Say what you want in HP and TQ at what RPM and so on and then someone can make a better recommendation. All these cams sound way too big for your basic set up. Something in the 220-230 duration at 50 is going to be more manageable. But what do I know. My .02

 

['64 Cuda]

66dartgt,

My block is a 1991 & is set up for the roller cam, which is a hydraulic. I can get the roller cam with new roller lifters, used dogbones, spider, & pushrods (I'd have to get a different set of pushrods as these are for Magnum heads) for about what I'd have to pay for a new roller cam. As far as horsepower & torque I'm looking for, it seems bigger is always better. I don't have to have a drag car, but I do want a nasty street car. Seriously, I think these are just a bit bigger cams than I need with what I've got, but now I am wondering how they would work with Edelbrock heads. That would bring my compression ratio up to the mid tens, which might make these cams a bit more suitable but I'm still a bit leery. The price on the roller stuff is good enough that I could probably buy them & sell the camshaft & still come out OK. Did you look at the Thumpr roller cam? It's close to specs of the Comp roller cam. It's listed as having an RPM range of 1900 to 5600, which sounds like a streetable profile. It's also just a bit more duration than what you recommended, but a little can make a big difference.

I feel like I'm rambling here. It's late & I can't think straight. :tongue3: I think I'll go to bed. Maybe I'll talk to you guys later this morning.


:burnout:

 

[66dartgt]

Cool with the roller capability. Now i understand a little better.

Something to keep in mind when looking at roller cams. The ramps are alot steeper than flat tappet cams, so when comparing duration figures you want to err towards the smaller side of a roller cam's dimensions. For instance a 230/240 roller cam compared to the same duration flat tappet cam - the roller is alot bigger in terms of the "area under the curve".

I built a 360 same vintage as yours. I had comp grind me a cam that I figured out to be a pretty good combination. My goal was to keep the lift under .500" so I could use the stock style springs on my #308 heads. I found some Isky springs that matched up to the extra weight of the lifters etc. The cam duration figures I ended up using was 218/224 int/exh with right at .500 or slightly less lift. It makes tons of torque and idles at around 1000 RPM. CR on my motor is 9.6, hope this helps.

What I'd do is buy one of these complete set ups you listed and have the cam reground to your specs. Call up comp, they can send you all sorts of lobe profiles to choose from. Then using a computer engine simulator, plug in some profiles and see what kind of numbers it runs and pick a profile. Keep in mind the computer program is a tool and wont be your absolute result, I figure the HP and TQ numbers for a street hot rod motor are about 50 units too high vs reality.

 

[snj60]

Maximum lift on stock 318 valve springs. Here is the question is there percentage or old standard to go by exceeding valve spring lift by cam by rockers arms. Without getting into valve spring pressures.

 

[BlueDream]

Maximum lift on stock 318 valve springs. Here is the question is there percentage or old standard to go by exceeding valve spring lift by cam by rockers arms. Without getting into valve spring pressures.

Take a look at the dates of the previous posts. This thread has been dormant since '07...