Thread: Cam questions

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So picked up a stock 1972 Chevy 350 4bolt with 1.94 heads for cheap because the guy broke a head bolt off in the block. The motor had a new oil pump and gaskets. I was able to easily extract the broken bolt. I decide to build it up a little. I had the heads milled down 20 thousandths (due to some damage). I had a family member over and he pulled one of the lifters out to check it and sure enough every one of them was cupped pretty good. So while the engine is out of the truck I'm just going to put a whole cam kit in it. I just want a cheap cam that will give me some more power. I was wondering if I need to be worried about the valves hitting the pistons with a bigger cam. I don't have the money to completely redo the heads with new valve springs and everything else. I was wondering if anybody had any suggestions for a cam I can use with all the stock head components and pushrods. I'm looking to stick with the hydraulic flat tappet. It's going in a 68 K10 with the stock 4speed. It will only see the roads with no off-roading but I would like to keep in mind it is a 4wd truck. Any input is appreciated

I would call Comp Cams, tell them what you are looking for. I once
used a 268 from comp and did not have to change anything in heads,
or torque converter. That was the advice they gave me then, but don't
know if they still make the 268, but maybe something similar.

Knowing what I now know about flat tappet hydraulic camshafts and lifters, I would advise the use of a Howards MC112011-11DL cam and direct lube lifters kit.
https://www.summitracing.com/parts/hrs-mc11201111dl
It will make good power from 800 to 4800 rpm's, has a good idle and generate good torque. Used for street, off-road and towing and you will have no worries with piston to valve clearance with the modest 0.420" valve lift. You will also have no noise from the lifters like you do with a Comp Extreme Energy grind cam. The noise if from the very fast open and close action of the EE cam lobe profiles. Harvey Crane identified this phenomenom several years ago, and named it "Hydraulic Intensity" You subtract the 0.050" duration from the advertised duration. The higher the number, the more gentle the cam is on the lifters and the rest of the valvetrain. The lower the number, the more violent the action is. If you're running a street motor, where there will be no frequent inspection of the internal parts, then use a higher number profile. If you are racing for money and will tear down the motor frequently for inspection, then pop for the faster valvetrain action with an Extreme Energy cam profile. Mr Crane used to cut all his cams on an H. I. of 62 and that was a reasonable intensity. Since then, other manufacturers have used H.I. down into the 30's for race motors. Some manufacturers, like Sealed Power and Melling and others, still use some VERY SLOW cam ramps, with H.I. up into the mid 70's. This particular cam that I'm recommending for you has an H.I. of 54, a reasonable balance between fast and slow ramps.
This cam and lifters will be warrantied for a full five years if you follow the installation instructions and use the oil additive shown below....
I don't know of any flat tappet hydraulic cam manufacturer who has offered such a warranty.

Use a bottle of this in the oil on cam break-in and a bottle of it in the oil with each subsequent oil change.
https://www.summitracing.com/parts/hrs-99000

Confidence! That’s what you get when you install a New Max Certified Cam and Lifter Set. A superior product with quality control goes far beyond, including batch testing and verification
on an Adcole 911NT. The Adcole is the premier measurement equipment for camshafts in the world. So you know you’re getting the finest camshaft for your application available. Each set
includes a performance hydraulic camshaft, a set of matching hydraulic flat tappet lifters and a bottle of Max ZPM oil additive for break-in (Max ZPM must be added to every oil change). So
what happens if you still have a cam damaging event?...You’re Covered! We will replace your Max Certified Cam & Lifter Set at no charge for up to five years from date of original purchase.
Just completely fill out the supplied warranty card and returnalong with your camshaft, lifters and the original receipt. No worries that you may have overlooked something that damaged
your new Max Certified camshaft. Didn’t notice that retainer to seal clearance wasn’t enough?...Covered! Valve spring coil bind...Covered! Have a problem with your oiling system that
damages the cam?...Covered! While installing the cam, you drop it and it breaks in two?...Covered! So what are you waiting for? Isn’t it time to make a real performance change to your
engine? With Max Certified Cam & Lifter Sets you’re covered! For extra insurance most kits available with Direct Lube lifters.

* Max Certified warranty applies to Max Certified Cam & Lifter Sets only. Max Certified 5 year
warranty starts from the original date of purchase. Any and all replacements are covered for
the remainder of the original warranty as long as any or all repairs or adjustments to end user’s
equipment, determined by Howards Cams, is completed. Max Certified warranty covers
camshaft and lifter set only. Warranty does not cover removal/installation cost, damage to related
components, cost incurred due to down time, towing or shipping. Warranty is non-transferable.
Warranty card must be completed for credit to be applied.

You will have to completely disassemble the motor and clean out every nook, cranny and oil galley. Pull all core plugs and screw-in plugs and clean everything. Use rifle brushes in the oil galleys, crankshaft oil holes and every other place where tiny ferrous iron shavings from the roached cam and lifters could be hiding. If you don't do this clean-up program, the new cam will likely fail in a short time.
https://www.summitracing.com/parts/mor-61820/overview/
Once you have cleaned everything with hot soapy water, dry the motor with a 2-stroke leaf blower. The hot air and small amount of oil film from the 2-stroke will leave the motor ready to assemble.

Finally, here is some good information on the care and feeding of a flat tappet hydraulic cam that I wrote several years ago....
http://www.crankshaftcoalition.com/w...ips_and_tricks

The price of this Howards cam and kit is pretty dear, but having another cam and lifters fail in your motor will cost you even more.

For those of you who want to keep track of technology with flat tappet cams, a SOLID flat tappet cam can use a small hole (approximately 0.020") EDM'd into the bottom of the lifter to squirt oil out from the bottom of the lifter directly onto the cam lobe. You cannot do this with a HYDRAULIC lifter, because you must maintain pressure inside the lifter body, so what Howards has done is to grind a small flat down the side of the lifter body to let oil squirt down the side of the lifter, between the lifter and the lifter bore, and directly onto the cam lobe. This is much the same idea as cutting a groove down the lifter bore to oil the cam lobe directly.
This video will explain how the grooving is done. This is a BBC, but any other V8 will be done the same....
https://www.youtube.com/watch?v=3hre40khS2c
Watch from 6:44 to 10:25

Note that the fellow in the video got driver's side and passenger's side confused there at the end......

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