miller
Well-Known Member
That's where you choose carefully, considering all parts involved. And, always check that piston to valve clearance!!!
Guides will be bronze.
Compression ratio concerns
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Guides will be bronze.
RRSweden
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Yes. As soon as I have all the parts back from the shop I will start by measure clearance with the old cam (270/270) wich will give me some pointers on what to choose. I hope the clearance is enough to feel confident to buy the comp XE268 shaft.
miller
Well-Known Member
Yes, sir. I'm sure some of the other guys will respond. But, since this is your first build...
Especially when tossing in non-stock parts, a handful of clearances must be considered.
The entire valve train needs to work together, not 'banging' into each other. What I mean is this...
Of course, piston to valve, and clearances while the motor is going through the strokes, by hand, valve spring coils, guide seals to valve spring retainers. Should have minimum clearances for those in the service manual. Main thing is no interference, from one part to the other. Just consider all the moving parts, and check by turning the motor, only by hand, until everything is good.
RRSweden
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By the way... The shop called, and gave me a really nice offer on 3-angle valves and seats. From what I've read thats a quite cheap cfm gain.
RRSweden
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Thanks! I will be careful!
Garys1969RR
Well-Known Member
You know, I'm running a .585 lift roller cam with 2.14 int and 1.81 ex valves. Duration @.050 is 243/249. I still have .080 clearance at the closest point. And my pistons are at .010 below deck. I have 4 small eyebrow reliefs in them. If you're running a shorter duration cam, under .500 lift, you should be OK. But you should always check it.
RRSweden
Well-Known Member
That's about the best information I could get at this point! Thank you!
(hmmmm... is it now I get greedy and start to look around for a bigger cam... ;)
Garys1969RR
Well-Known Member
I just put some light springs on 2 valves, set the lash, and turned it over near the overlap @ TDC position. I checked clearance by putting an .080 stack of feeler gauges between the valve tip, and rocker arm tip. That method has always worked good for me. Especially if the heads are already on the motor. Need to use a solid lifter and adj rockers to check it like this.
RRSweden
Well-Known Member
http://www.forbbodiesonly.com/moparforum/threads/comp-xe274h-with-lifters-
Thanks again for all the help
I've asked a friend for 2 solid lifters to borrow. Since I don't have adjustable rockers I will measure with the clay-method. But it sure feels promising after reading about your setup, and your way more agressive cam than I will buy!
Thanks again for all the help
Garys1969RR
Well-Known Member
Sure! You will need some way to get your valve lash to zero before checking it. I guess 2 adj push rods would work. Clay method works good!http://www.forbbodiesonly.com/moparforum/threads/comp-xe274h-with-lifters-
I've asked a friend for 2 solid lifters to borrow. Since I don't have adjustable rockers I will measure with the clay-method. But it sure feels promising after reading about your setup, and your way more agressive cam than I will buy!
Thanks again for all the help
RRSweden
Well-Known Member
Hi again. The engine build has started! So far, so good...
A thing that striked me now is about the push-rods. I've assumed that I could use the same rods as I used with my 906 heads on this set of 915 heads.
Is that correct?
(the push-rods I have is Sealed power RP-3191 wich measures: 8.5750")
A thing that striked me now is about the push-rods. I've assumed that I could use the same rods as I used with my 906 heads on this set of 915 heads.
Is that correct?
(the push-rods I have is Sealed power RP-3191 wich measures: 8.5750")
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Should be able to unless the 915's have been milled a lot.....
Garys1969RR
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I believe all the push rods for the different heads have the same length. As long as it's a low deck. Hi deck motors are longer, of course. And I'm pretty sure there are 2 different hydraulic lifters that require different length push rods. I think the lifter height changed in 67 or 68. So keep in mind what year your lifters are.
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I did not read the whole thread,but I see 8:1,,,,,I think BOOST!
RRSweden
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With new pistons and closed chamber heads the comp is now 10+:1I did not read the whole thread,but I see 8:1,,,,,I think BOOST!
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NO BOOST!
,,,,,8 or 8.5:1,,,BOOST,,,,,,,
,,,,,8 or 8.5:1,,,BOOST,,,,,,,
RRSweden
Well-Known Member
...
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Garys1969RR
Well-Known Member
How is your 383 build coming along, RRSweden? Haven't heard from you in awhile. Are you done with your motor? How does it run?
RRSweden
Well-Known Member
It finally came together two days ago. I'm soon gonna post you all some pics and info about the build. Haven't started it up yet, cause I'm worried about my flywheel being a little bit cracked...
Stay tuned!
RRSweden
Well-Known Member
Here's a few pics from the build.
Crank was cut .010 and blasted spotless.
measured between 0.0015 and 0.0020 clearance with plastigauge on all journals.
crank endplay .006" (0.155mm)
the 915 heads milled .010 with new valve guides and seats. Valves back cut 30degrees. Combustion chamber measured 74cc.
Piston to deck measured .022"
Crank was cut .010 and blasted spotless.
measured between 0.0015 and 0.0020 clearance with plastigauge on all journals.
crank endplay .006" (0.155mm)
the 915 heads milled .010 with new valve guides and seats. Valves back cut 30degrees. Combustion chamber measured 74cc.
Piston to deck measured .022"
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