Looking for camshaft grind.

[Bubbagum]

Looking to upgrade my camshaft to a retro roller. Stock 350 out of a 1982 corvette with throttle body’s. I want a grind with high torque off or near idle that will have good vacuum. Street not race. Can anyone give me an idear what to look for. I was told no more than 112 lsa for vacuum but the rest is beyond my experience. One profile was howard 110315-12. The other Melling 22135. Trying to keep it just above stock. The heads are brodix 180 cc 64 cambers. Not winding it any more than 5000rpms. Bottom end is stock all rebuilt.
Thanks Kevin

 

[Bubbagum]

No response. I hope I posted in the right place.

 

[Grumpy]

howard 110315-12 looks good but read the linked restrictions,
you'll need to use better aftermarket valve springs, check clearances and use a cam button. with any cam you use
sorry for the delay in response ,I'm. in and out of hospital and have several months of recovery with my knee replacement surgery

 

[Indycars]

Your Dynamic Compression Ratio (DCR) could be too high depending on other factors. What octane fuel are you planning on using?

What cam are you using now, OEM ?

 

[Bubbagum]

Your Dynamic Compression Ratio (DCR) could be too high depending on other factors. What octane fuel are you planning on using?

What cam are you using now, OEM ?

Hi Rick. I thought I had posted in the wrong part of the forum. I was looking for a correction if it was. Thanks for responding. I do want to run it on 87 octane and detonation was a concern. It slipped my mind because people kept commenting on my plans with a small cam with brodix heads. I'm trying to get the most with what I got. It's a crossfire that I'm porting. I'm ditching the 462624 heads that were working fine. Smog, crack prone thin casting and the camshaft original flat tap for a retro roller. The Brodix has roller springs figured a savings. 180 cc and 64 cc I think I can change the camber size if needed. The bottom end is stock, and all rebuilt by me. Pistons 464664 were stock trw flat top pistons, king bearings on cast crank and stock rods. Clearances were all within specs. It only had 68000 miles on it. You know the old saying if it not broke don't fix it. The old cam that came out was perfect. Looking to get off the self-oil, not to worry about flat tappets was my thought. I also have to update the computer to a 7747 or 8746 and maybe it will let me upgrade the knock sensor. Any help you can give me much appreciated. Howard nice guy said a 110315-12 would work. I was also looking at two more Melling 22135 and one from comp cam 12-464-8. The lift seam high on that one. I waited close to a half hour to talk to them and that's what he recommended. He wasn't in the best of moods maybe just answering questions all day, I don't blame him, so I kept it short. I'm looking for vacuum for break and headlights. good low-end torque and if the rpm gets to 5000 that's a win. thanks again Kevin

 

[Bubbagum]

howard 110315-12 looks good but read the linked restrictions,
you'll need to use better aftermarket valve springs, check clearances and use a cam button. with any cam you use
sorry for the relay in response ,Im. in and out of hospital with my knee replacement surgery

Hi Grumpy. Thank for responding. Your contribution to the car community is much appreciated and your articles and tips are among the best in the country. Obviously, I wasn't aware of your surgery, and I wish you a speedy recovery. I'm sure that I'll get the assistance from the car community here and thank you for your input and yes doing my best to double check my clearances. get well soon. Thanks Kevin

 

[Indycars]

We need to get some hard numbers so we are not guessing. Do you know what the valve relief size is in CC's for your pistons? Does the photo below look like your pistons? Can you provide the numbers for rows 2 thru 8, the others are insignificant except for row 12 (IVC). I can figure out the IVC for you or use page 2 of the calculator, see below.

The Howards cam closes the Intake Valve (IVC) at 57° ABDC.

dynamic vs static compression

its obvious some of the guys on this site need to understand the difference between static and dynamic compression ratios, and that's understandable as its a difficult concept to grasp at first. your engines tendency to get into detonation is the result of higher effective compression that the...

garage.grumpysperformance.com

You need to shoot for a DCR of about 7.7 with aluminum heads to use 87 octane. What do you think @Grumpy is that about right?

If you have Microsoft Excel, then you can download the calculator and run your own numbers.

http://garage.grumpysperformance.com/index.php?forums/spread-sheets-and-engine-related-forms.99/

 

[Bubbagum]

We need to get some hard numbers so we are not guessing. Do you know what the valve relief size is in CC's for your pistons? Does the photo below look like your pistons? Can you provide the numbers for rows 2 thru 8, the others are insignificant except for row 12 (IVC). I can figure out the IVC for you or use page 2 of the calculator, see below.

The Howards cam closes the Intake Valve (IVC) at 57° ABDC.

View attachment 17404

View attachment 17405

dynamic vs static compression

its obvious some of the guys on this site need to understand the difference between static and dynamic compression ratios, and that's understandable as its a difficult concept to grasp at first. your engines tendency to get into detonation is the result of higher effective compression that the...

garage.grumpysperformance.com

You need to shoot for a DCR of about 7.7 with aluminum heads to use 87 octane. What do you think @Grumpy is that about right?

If you have Microsoft Excel, then you can download the calculator and run your own numbers.

http://garage.grumpysperformance.com/index.php?forums/spread-sheets-and-engine-related-forms.99/

#2. 4.00 #3. 3.48. #4 64cc #5 .020 #6 .041 #7 4.166 The piston do look like the ones you show. There are one eye brow. Stock # 464664 The pistons are old trw forged piston gm used. I have tried to cross reference them with no luck Other than skirt measurements. They look identical to your picture If yours is standard size. The head gasket I was going to use is the Fel-pro 1003. Those should be the right spec. If you could run the numbers, I would appreciate If not thank for helping. I‘ll see if I can download the program. I’m using an iPad. Thanks Kevin.

 

[Indycars]

I can't find a number for the valve reliefs that I'm confident in using. Looks like you will need to measure this volume. You could fill the trough with modeling clay, then scrape off everything above flat surface. Drop this into some liquid and see how much the volume increases. I'm assuming you are NOT doing a complete tear down of the engine since you said you have just rebuilt it.

You will need a thinner head gasket to get your quench distance down to .040" to .048". This will help reduce the tendency for detonation to happen. I would also reduce the gasket bore diameter to around 4.060".

 

[Bubbagum]

I can't find a number for the valve reliefs that I'm confident in using. Looks like you will need to measure this volume. You could fill the trough with modeling clay, then scrape off everything above flat surface. Drop this into some liquid and see how much the volume increases. I'm assuming you are NOT doing a complete tear down of the engine since you said you have just rebuilt it.

You will need a thinner head gasket to get your quench distance down to .040" to .048". This will help reduce the tendency for detonation to happen. I would also reduce the gasket bore diameter to around 4.060".

Hi Rick
Hey thanks a lot. My god I am crashing numbers myself with these online calculators. Unbelievable. I know what you mean now. I’ll try what you said with the clay. Won’t be for a few days. Fathers birthday. 93. I did find someone searching for the same. Somone gave him 7cc. I’m going to check it your way and get back. If it is going to be high the same heads had an option for 70 cc cambers. I’ll get back with that piston volume. Your very helpful. Thanks again Kevin.

 

[Grumpy]

yes 7cc is quite common but not exclusively unique on those engines, Ricks been very helpful, yes you'll benefit from getting the quench down to about ,046-.040 and selecting a head gasket bore diameter that's only slightly larger than the existing bore diameter. THANKS RICK!
btw Ive used SCE copper head gaskets exclusively for decades and never had any issues, and yeah, 462624 heads are some of the worst performing heads out there!
the OEM crossfire heads for 1984 are casting number 462624 76cc heads
462624 chevy head flow numbers
(these are the heads that came on the 1984 corvettes)
just a bit of info on those stock #624 head flow rates

.......intake....exhaust
.100..44..........41cfm
.200..101..........82cfm
.300.155..........125cfm
.400..182..........137cfm
.500..196..........140cfm
more info in links


related thread links

tumble and swirl, quench & squish

I could fill chapters on these subjects, but its basically not something the average engine builder assembling off the shelf parts needs to be overly concerned with other than to understand the potential power may change due to the parts selected and the careful assembly and measurement during...

garage.grumpysperformance.com

SBC Head Gasket choice.

In a previous life the block was 0 decked then stroked to 383 and now the pistons sit out of the hole .015in, bore is 4.040in. Looking at readily available stock. Block wasn't particularly finished for MLS, heads Alum afr. Cometic isn't a choice. Daily driver. GMPP is the tightest at 4.100in...

garage.grumpysperformance.com

calculating piston pin height/compression height

" HEY GRUMPYVETTE? I picked up a tall deck,Chevy big block 427, block, at a yard sale and a friend donated a set of 454 .060 pistons Ive got several intakes for big block engines ,both oval and rectangular port, styles, whats it going to take to build a 496 stroker from these components?" it...

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What Head Gasket??

So as per strong suggestions I was going to be using a set of .015 FelPro Steel head gaskets 1094 with brush on Sealing Compound-RTV 5920 Copper Silicone Gasket Maker Loctite 37466. These head gaskets are NOT Permanent Torque gaskets and it is STRONGLY suggested to retorque after a hot cycle...

garage.grumpysperformance.com

head chamber volume needs clean-up/ equalization

Just got my heads back an cc'd them from being decked and checked for valve leaks. 5 were at 62cc and 3 at 63cc. I would like to know the best place to grind out the 1 cc in the 5 chambers so they all match. Or is this to close to worry about it? Vortecs are said to be very touchy so I don't...

garage.grumpysperformance.com

ccing my heads

HELP I hope some can help me with a prob I am having. I started to cc my heads so i check all and found that they need to be ground. I have one at 64.3 so I started grinding one of them to be at 64.3 or there abouts. I ground a lot off and got a reading of 62 so I ground more off and came up...

garage.grumpysperformance.com

SBC Head Gasket choice.

In a previous life the block was 0 decked then stroked to 383 and now the pistons sit out of the hole .015in, bore is 4.040in. Looking at readily available stock. Block wasn't particularly finished for MLS, heads Alum afr. Cometic isn't a choice. Daily driver. GMPP is the tightest at 4.100in...

garage.grumpysperformance.com

http://garage.grumpysperformance.co...ng-combustion-chambers.2630/page-3#post-77963

engine assembly tips

the first few rule's of GRUMPY'S engine assembly (1) THINK THINGS THROUGH CAREFULLY , WRITE DOWN A LIST OF COMPONENTS , MAKE DARN SURE THE LIST IS COMPATIBLE WITH, and AT LEAST SEMI-REASONABLY PRICED WITHIN YOUR BUDGET. FOR WHAT YOU INTEND TO BUILD AND RESEARCH THE RELATED MACHINE WORK...

garage.grumpysperformance.com

dynamic vs static compression

Blows the theory out of the water that short rods give better detonation resistance. The link article & Trigonometry show Long Rods do it instead.

garage.grumpysperformance.com

(X) or (H) PIPE

that is the ultimate "headers for dummies" video... nice demo!

garage.grumpysperformance.com

 

[Indycars]

Hey thanks a lot. My god I am crashing numbers myself with these online calculators. Unbelievable.

No need to thank me, I'm having too much fun. I'd fee guilty if you thought I was doing this just for you!

Which online calculators are you using??? To be accurate you need to know the IVC precisely. Some online calculators estimate the IVC (On the Seat) but ask you to input IVC at 0.050" of valve opening. On the seat is defined by the Society of Automotive Engineers (SAE) when the lifter rises .006" off the base circle of the cam until it's back to within .006" of the base circle again. That's typically called "Advertised Duration" by the cam manufactures.

Maybe you heard of SAE, remember buying oil ...... SAE 10W30 ??? Their standards are everywhere in the industry.

The Mission of SAE International is to advance mobility knowledge and solutions

SAE International is a global standards development and professional association with over 128,000 engineers and technical experts in mobility engineering.

www.sae.org

I've been running some simulation using my Dynomation 6, but until we have more concrete info like the valve relief I'm not posting the results. It will just confuse things when I have to go back and update the basic parameter.

Won’t be for a few days. Fathers birthday. 93.

Enjoy, my father lived to be 96. Boy did he have some stories to tell about growing up in OKC!

If it is going to be high the same heads had an option for 70 cc cambers. I’ll get back with that piston volume.

Looks like you are in the sweet spot, if one chamber volume doesn't work the other will. There are other ways to get there, just changing the where the cam is install can make a nice difference. It's very common to move the Intake Centerline by 4°. In your case it's probably going to be retarding the cam by 4°.

 

[Bubbagum]

Hi Rick
Checked the piston today and got 5cc.
https://www.gofastmath.com/Compression-Ratio-Calculators/Camshaft-Valve-Timing-Degrees-Calculator

 

[Indycars]

Thanks for that info!

I thought for sure that you needed a cam that was compatible with computer control, but when I look up your Howards 110315-12 cam it is NOT compatible.

So while I'm looking thru possible cams, do we have to stay with something computer compatible?

What are you using for the exhaust system, OEM ??? I'm running some engine simulations.

For a head gasket I would suggest a SCE copper gasket with a .021" thickness and a bore of 4.060". Just make sure this is correct for your application. Copper can be reused several times. It does NOT require an o-ring like it says per the instructions, Grumpy has used it many times without and I am using it without the o-ring presently in my TBucket engine and have reused it 3 times now.

CHEVROLET SCE Gaskets P110621 SCE Pro Copper Head Gaskets | Summit Racing

Free Shipping - SCE Pro Copper Head Gaskets with qualifying orders of $109. Shop Head Gaskets at Summit Racing.

www.summitracing.com

Other possibilities are:

CHEVROLET 5.7L/350 Chevy small block Gen I Head Gaskets Gaskets & Seals - 4.060 in. Bore (in.) - 4.065 in. Bore (in.) - 4.093 in. Bore (in.) - 0.021 in. Compressed Thickness (in.) - 0.023 in. Compressed Thickness (in.) - 0.027 in. Compressed Thicknes

Find CHEVROLET 5.7L/350 Chevy small block Gen I Head Gaskets 4.060 in. Bore (in.), 4.065 in. Bore (in.), 4.093 in. Bore (in.), 0.021 in. Compressed Thickness (in.), 0.023 in. Compressed Thickness (in.), 0.027 in. Compressed Thickness (in.) and get Free Shipping on Orders Over $109 at Summit Racing!

www.summitracing.com

 

[Grumpy]

yes for decades I've used solid copper head gaskets in dozens of engine builds without a single issue
read links and use the copper coat spray as the links suggest and you'll have decades of usage without issues if you use solid copper head gaskets

SBC Head Gasket choice.

In a previous life the block was 0 decked then stroked to 383 and now the pistons sit out of the hole .015in, bore is 4.040in. Looking at readily available stock. Block wasn't particularly finished for MLS, heads Alum afr. Cometic isn't a choice. Daily driver. GMPP is the tightest at 4.100in...

garage.grumpysperformance.com

 

[Bubbagum]

Using a 8746 ecm and 2.1/2 exhaust with stock manifolds And turbo mufflers. .041 4.166 felpro head gasket. I don’t want the cooper gaskets.

 

[Indycars]

I had already done the simulation and pulled the graph into PhotoShop, so I made the changes back to a .041" thick and 4.1" head gasket. The chance for detonation is unknown, it could go up or down. Especially for the Crower cam. The DCR dropped, but the quench distance also increased significantly to .061".

I ran two other camshafts, one by Crower 0046 and CompCams XR258HR, both cams were near identical and the graphs lines were on top of each other.




Howards Cam

 

[Bubbagum]

Hi Rick Thanks
The quench how does that play a role on detonation? Is it the smaller the area the better, even though it raises compression. Is it the space between the piston and head, on the flat side, doesn't let it burn right. Thats why you had recommended the copper head gaskets.
The dynamic compression with the Howard is 7.72. Would that mean. I could run 87 octanes/ 93. What is a goal for dynamic compression at 87 octane vs 93.
I don't know if I pointed it out here, or another forum. Howard cam specs on some vender's sights, has 110 lobe separation on 110315-12. Don't know what's going on, but Howard sight post 112. So, I'm going by that. Let me know if you caught that.
That threw me off a little. I had to give it a break for a couple day. I like that program you have.

 

[Grumpy]

you can also install the cam at split overlap or retarded 4 degrees, from the dot to dot location, this reduces the effective compression marginally and raises the whole power band about 200 rpm.(both factors should help your engines power band and reduce the engines tendency toward detonation.)


a bit of reading helps

checking piston to valve clearances

this is an old post I got asked to repost, naturally the first step is to install and correctly degree in your cam, http://garage.grumpysperformance.com/index.php?threads/measuring-piston-dome-volume.17255/...

garage.grumpysperformance.com

quench & squish

quench area: http://www.chevyhiperformance.com/tech/ ... index.html http://www.chevyhiperformance.com/techa ... index.html http://www.rbracing-rsr.com/squishcalc1.html http://www.klotzlube.com/techsheet.asp?ID=87 ]read thru these threads also[/b]...

garage.grumpysperformance.com

http://garage.grumpysperformance.com/index.php?threads/the-ideal-cam-lca.2782/#post-7433

dynamic vs static compression

its obvious some of the guys on this site need to understand the difference between static and dynamic compression ratios, and that's understandable as its a difficult concept to grasp at first. your engines tendency to get into detonation is the result of higher effective compression that the...

garage.grumpysperformance.com

how your cam LSA effects your compression ,torque , DCR

TIGHTER 104-110 LSA tend to increase scavenging efficincy but at the cost of less smooth idle LSA lobe separation angle is locked into the cam when its ground and can not change, if its ground at 110,degrees or 114 degrees it will stay that figure and LCA lobe center angle, can be...

garage.grumpysperformance.com

The Mechanics of Adv/Ret a Camshaft ?

Without getting into the $150 and up range for timing gears and chain. There seems to be only two ways to adjust the timing for under $75, the crank gear can have several keyways or you can drill the cam gear and use bushings. Pulling the crank gear would be alot more of a pain to change, than...

garage.grumpysperformance.com

 

[Indycars]

The quench how does that play a role on detonation? Is it the smaller the area the better, even though it raises compression. Is it the space between the piston and head, on the flat side, doesn't let it burn right.

It helps by the piston coming so close to the head that the gases are shot out at high velocity and mix with the other gases creating a better homogeneous mixture that doesn't have lean or rich areas.

Quench also cools the gases. You have to be aware that if you have .040" of clearance when you measure it in the shop is not what the clearance will be when the engine is running. With heat you have expansion and with RPM you have stretch in the materials, so in actuality the quench distance might be only .015" or less.

To answer your question ...... Yes smaller is better up until you have piston to head contact. Yes it is that area where the piston is flat and matches the head that is also flat, shown as orange in the graphic below. Not that it wouldn't burn right (kinda), but it can be very helpful in reducing detonation with little increase in the compression ratio.

Quench: Unlocking Performance Squished Between the Piston and Head

Quench is the clearance between the piston and cylinder head at TDC. It can affect engine effeciency and performance, if you truly understand it.

www.enginelabs.com

The dynamic compression with the Howard is 7.72. Would that mean. I could run 87 octanes/ 93. What is a goal for dynamic compression at 87 octane vs 93.

I have to use 91 octane with a DCR of 8.02 and that's on the limit. I did have a DCR of 8.27, but had a mild case of detonation until I retarded the cam by 4°. But this is my only experience with this situation. So that's why I guessed in a previous post of 7.7 DCR. You will at least have a choice of a higher octane, but all I can get where I live is 91 octane. You will have 91 or maybe 93 octane if your off a little.

But I would like to see what Grumpy says, he's got 100 times more experience with this then myself.

@Grumpy - So Grumpy, what do you think is a good DCR for Bubbagum's engine to run on 87 octane.

I don't know if I pointed it out here, or another forum. Howard cam specs on some vender's sights, has 110 lobe separation on 110315-12. Don't know what's going on, but Howard sight post 112. So, I'm going by that. Let me know if you caught that.

My numbers posted above are also from the Howards website, just a different page. I did a search for the part number 110315, clicked on the -12 cam. Next click on the "Details" tab and there you will find what I posted above ..... LSA of 110°.

So I guess you might want to check with Howards to see what is going on.

I like that program you have.

Which program is that Dynomation or the Excel spreadsheet?
.