chrgdrt
Well-Known Member
I was thinking more about piston to head clearance, isn’t.030 quench a bit tight? Maybe I’m missing something here
CAM HELP NEEDED!
- Thread starter spd691
- Start date
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The next cam to be installed by me;
Hydraulic Flat Tappet Camshaft & Lifter Kit; 1964 - 2003 Chrysler 273, 340, 360 1800 to 5800 Howards Cams CL711451-08 | Howards Cams
Going in a stock long block 5.9 w/a 750, RPM, 1-3/4 headers, 727/2500-3.55’s in a ‘79 Magnum riding on 245/60/15’s on all 4 corners. The 1.6 rockers will increase the lift to .539/.540.
The ‘79 Magnum has a listed weight of 3675. It was lightened only by the carb, intake, headers & missing A/C parts in the engine bay.
If you want to get a little nit picky, the electric window doors were swapped out for roll up your own window doors because there is no rust on them.
Well, yea.030 is tight. I’ve run tighter. You have to be sure there is a bunch of V to P clearance. I’d rather run a .038-.042 on the engine with stock rods. Quality aftermarket rods can go less since there is normally less rod stretch at a higher rpm.
The quench difference on the street and most track applications isn’t going to be noticed.
Most current build in progress will have a .032.
That's tight. What do you like for P/V clearance?
I am running stock length H beams, forged stock crank, pistons machined down to achieve zero deck. I can use my head gasket of choice to achieve the quench I am leaning towards .030 MLS. The block has been decked for finish for the MLS gaskets and aluminum heads
As a min.? I can’t remember having an issue and the only guide I’ve have followed was the MP engines book which to be honest gives measurements and clearances to a slightly generous size because many people out there will push the limits of what they suggest and screw up there engine. So the MP books suggest a “SAFE” clearance measurement.
Follow that and you’ll not have a problem.
The closest I have ever run a clearance I didn’t measure and dang well should have! I installed a Comp solid 296S w/a .525 lift, then the proper lash was done (which was generous because the engine was cold) and found that the intake valve, while not hitting the piston was so close it did not allow the black carbon to left behind on the piston like the quench area does and that quench was .028.
IMO, you’re unnecessarily close. The thing people forget is, during high, RPM operations, the piston will stretch the rod. How much stretch there is depends on a few factors, but do not kill yourself that the rod will stretch and stretch a lot depending on what going on in the build. a heavy piston on a heavy rod at high RPMs can’t move that rod a good distance.
Like I said earlier, the street or bracket engine that has an extra 10,000 clearance and quench will not be noticed. The difference between 30 and 40 in clearance is not going to be picked up. Will it show on a Dyno, yeah probably I’m sure. Do you need the extra 357 hp?
Run what you want at your own risk. I can’t be a fortuneteller. I adhere to some safe practices myself. I’d really not rather gamble my money away on a minor power gain by closing up the quench.
I thought .100
.100 piston to head? 
Valve clearances are in that spec.
The issue I had described above was because I slide the crank timing gear on the wrong setting, being 4*’s advanced.
WHOOOOPPPSSS!
Almost a really bad day!
Valve clearances are in that spec.
The issue I had described above was because I slide the crank timing gear on the wrong setting, being 4*’s advanced.
WHOOOOPPPSSS!
Almost a really bad day!
Piston to valve clearance..100 piston to head?
Valve clearances are in that spec.
The issue I had described above was because I slide the crank timing gear on the wrong setting, being 4*’s advanced.
WHOOOOPPPSSS!
Almost a really bad day!
I will be checking VTP clearance, if necessary I will modify the intake pockets. General rule is .100 should be safe on the intake. From what I have read.
Newbomb Turk
Well-Known Member
That’s where the FUN is!!!
Newbomb Turk
Well-Known Member
You can go as tight as .050 on the intake IF you are careful. And .080 on the exhaust IF you are careful.
If you want a little margin add .020 per side and send it.
Now that that’s said, the truth is most pistons come with valve pockets far deeper than they need to be.
I’d be surprised if you don’t have .200 or better on both sides. Check it, but don’t be surprised.
Ill be checking it, I just need to find the cam. I think I settled on one from Howards, less lift and little closer to my realistic range, HOWARDS CAMS 718001-09
Camshaft Series:
Rattler
Year:
1964 - 2003
Make:
Chrysler
Engine:
273, 340, 360
Camshaft Type:
Hydraulic Flat Tappet
Basic RPM Range:
2000 to 5800
Valve Lift Intake:
.480
Valve Lift Exhaust:
.488
Duration Intake:
281
Duration Exhaust:
289
Duration at 050 Intake:
227
Duration at 050 Exhaust:
235
Lobe Separation:
109
Intake Centerline:
103
Lift: .480 / .488, Duration @ .050: 227 / 235, Centerline: 103, Rattler, Choppy idle, High performance street, Stock converter ok, Best with 1800+ & gears
My build is similar to yours - 73 Sport 340, Eagle crank with H-beam rods, JE flat top pistons, decked, Edelbrock heads, RPM Air Gap intake, 750 Holley, Schumacher headers, 3.91 Sure Grip and Chevy 200-4R trans. 1.6 roller rockers. I got with B3 Engines for their geometry correction kit for the rockers. This is the cam I'm running, a solid flat tappet - Comp Cams Xtreme Energy 244/252 Solid Flat Cam and Lifter Kit for Chrysler 273-360
Ahhhh, Howard’s answer to the Comp Thumper line.
Isn’t lifting up the valve enough for you @ .520?
ENJOY!!!!
I submitted my build and car info to Howards. Ill wait and see what they recommend. I just hope they have something in stock.
4eighteener
Well-Known Member
Hughes cams does this on all their cams for what I thought was proprietary reasons. Comp cams just seemed to do this on their roller cams.
When I check for dcr or vp on wallace to compare cams I just guess and add 20 to the .050 number. Not sure that is right
Yea, I'm not sure. I guess ill wait and see what Howards says.
Dan the man
Well-Known Member
The OP seems to want to run less duration then originally recommend, and I was just saying that generally gonna come with less lift.
I don't know if so called RV cams come with more lift for a given mild duration, Far as I understand it's generally used for slang for mild cams.
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Dan the man
Well-Known Member
With the silicone sisters. And go cart Motzart. And little early birdie.
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