Engine Build thoughts.

[69Beauty]

this is my first engine build (im 15) and was wondering what you think about my setup so far.
a 3970010 block .030 over
standard crank standard rods
keith black 193 pistons
keith black rings
fel pro .015 steel shim head gasket
stock cylinder deck (dont know how far down)
vortec heads with minor porting
lunati 60102 cam 1.5 rockers
edelbrock performer rpm intake
rebuilt qjet carb
th350 trans
this is going into a 1969 c-10 long box.
the trans is newly rebuilt but has no stall.
and recommendations would be welcome.
and if someone would be kind enough to run this through your desktop dyno that would be greatly appreciated.
thanks
logan

[faribran]

i dont know anything about the camshaft.. but i sure like the rest of the build....
i am sure someone will jump in here and share some more info about your combo.

[Kokomoooo]

Yes, with a head gasket that thin, check the piston to cylinder head clearance. Trust me, if you don't have .050" clearance, the pistons WILL hit the heads. Yes, I know this from experience!!!!

[69Beauty]

it has more than .015 clearence because of how far the pistons are in the hole. that is why i have a thin head gasket. and there is no way that .050 is needed for clearence when .040 quench is what is best for preventing detonation.

[Kokomoooo]

Originally Posted by 69Beauty

it has more than .015 clearence because of how far the pistons are in the hole. that is why i have a thin head gasket. and there is no way that .050 is needed for clearence when .040 quench is what is best for preventing detonation.

Smokey Yunick says .050 minimum, but you probably know more than he did. You asked for opinions, but hey, its your engine. My experience has usually been that the pistons are between .010" to .014" down. But if you want to trust it to chance..........

GOOD LUCK!!!

[butters_72]

for me to run it on my dyno i need to know the cfm of your carb and what kinda exhaust your running, ie single, dual, headers, stock manifolds?

[69Beauty]

It is around 750cfm and I'll put 1 5/8 primary Long tube headers with dual exhaust. Thank you for the help. And just a guess I think the pistons ar about .021 in the hole. My comp ratio is about 9.6
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[69Beauty]

I'm not trusting it to chance it's just that I haven't put the pistons in to measure it and thy was just a guess of sorts. Maybe smokey ia right but from what I have read .04 to .045 is best quench but again this is just what I have heard and I am still learning.
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[69Beauty]

I just ran it through a Dyno i downloaded and it said it should be at about 350hp @ 5000rpm and around 420 Ft-lbs @ 3500rpm but that is just a cheap one so it is probably off a little bit.

[5150.4.67]

You have a great start!
Keeping your quench within specs (0.035-0.045) and while still having a decent DCR (dynamic compression ratio) is why doing your homework before the build is crucial. Also, if your DCR is a little high, you could bring it down with cam duration as well. Check your piston to valve clearance as well (at least 0.080, this may be what kokomooo is referring to), especially with a high lift/duration cam.
Check out Keith Blacks website for calculators (if you haven't already).
Good luck!

[Kokomoooo]

Originally Posted by 5150.4.67

You have a great start!
Keeping your quench within specs (0.035-0.045) and while still having a decent DCR (dynamic compression ratio) is why doing your homework before the build is crucial. Also, if your DCR is a little high, you could bring it down with cam duration as well. Check your piston to valve clearance as well (at least 0.080, this may be what kokomooo is referring to), especially with a high lift/duration cam.
Check out Keith Blacks website for calculators (if you haven't already).
Good luck!

Actually, I know exactly what I am talking about. I was trying to help him avoid the same mistake I made when I was very young. I used a .017" gasket with what turned out to be pistons that were .014" down the hole, and no, I did not check them. They hit the heads as soon as I started the engine. Destroyed all of them!!! Unfortunately, I didn't have people I could ask, so I didn't know.

He says the thickness is .015", is that as measured, or compressed thickness? Steel shim will also compress, just not as much as composition gaskets. You need to know!!!

Thats one heck of a risk to take, I hope that he gets away with it, but I doubt it.

If you ask for opinions, then ignore advice without checking the facts, then your just wasteing time asking. Advice is after all, warnings as to what to watch out for.

[llowlife]

.035-.040 quench is fine You will be probably be as you thought 020-025 in the hole or so. You really should measure it.

I assume you are using stock rods? If so throw the bolts away and put in some ARP's. You will need to get them resized though for safety. Rod bolts are not the place to save money unless you are going to keep the rpm's reasonable......Ummmm I was 15 once too and I know it WILL at least one time in its life turn too many RPM.If you cut corners on the rod bolts it may only turn too many RPM's once.

Cam looks good however what is the max lift on a set of stock vortec's? I thought it was .480? Your cam is running 489 I think. SHOULD be okay. Personally I would tighten the LSA to get better breathing but Harold designs a good cam.

Whisker above stock stall might be helpful.

Sounds like a decent entry level engine. I think your Hp and torque expectations are reasonable provided you put it together correctly with tender loving care. I have seen more hp from lesser parts when molded correctly. It took me over 100 hours to build my last motor and I have been building them for over 30 years. TAKE YOUR TIME AND MAKE NO COMPROMISE because you are getting sick of working on it. Be patient and do it right, when you get sick of it....walk away.... Mock sub assemblies up and check fit. Get all your subassemblies right and bolting it together for the last time is fairly quick and easy.

[llowlife]

I have never seen a gasket thickness listed as non compressed, always compressed thickness, and a steel shim is just that .015. He needs to measure the in the hole numbers but I have run my street motors at or below .040. Race motors I will run to .030. small quench as long as you are not "smacking the heads". You can increase compression slightly or run pump gas at 10.5:1 or so on CI heads. A tight quench cuts the combustion chamber in half as far as the flame front is concerned. A large quench usually extinguishes the flame front when it gets too it thereby increasing hydrocarbons and reducing power to an extent. It will also add a nice "swirl" to the mixture for increased power as it expels the gases into the combustion chamber. Some of my more "adventurous friends" have run down to the low -020's though that is highly NOT recommended . Wanna run .050...Run it. You need to measure ALL the "in the holes" as the deck is probably not "square" If you do not measure the in the hole do not run a steel shim. End of my input on this thread, but below is the subject as covered by DV

Combustion Chamber Dynamics - David Vizard
A cool charge may be the first step toward utilizing a higher CR, but what happens in the combustion chamber can make or break any such efforts. A prime factor here is never to loose sight of the fact that the faster the charge can be burned the higher the compression the cylinder will stand. Chamber cavities between the piston and the cylinder head between about .060-inch - .0120-inch appear most likely to be the site of detonation. Speeding up combustion mixture motion/agitation is vital. This means maximizing the quench action. On a small-block Chevy with a stock block height, a stock compression height piston is typically .025-inch down the bore. With a .040-inch gasket this makes the static quench clearance .065-inch, which is way too wide. By cutting the quench clearance the burn rate and quality improve to the point where the motor gains compression and is less likely to detonate even at the higher ratio involved.

So how closely can the pistons approach the head face? Although it comes under the heading of "don't do this at home" I have run the static piston/head clearance down to as little as .024-inch in a 350 with stock rods and close-fitting hypereutectic pistons. The pistons just kissed the head at about 7,000 rpm. As far as power is concerned, an associate of mine ran some tests in a nominally 450-horse 350 and found that each 10 thousandths of quench reduction was worth approximately 7hp. If you are building from scratch, make maximizing the quench your number one priority toward achieving compression and avoiding detonation.

[Kokomoooo]

OK, maybe he said .040, point is you better make sure!!!

Read the first line in his post:

Quote:this is my first engine build (im 15)

In other words, he has zero experience!!!

http://www.chevyhiperformance.com/te...ide/index.html




Since piston clearance plays such a big part in piston-to-head clearance, it is possible to run a piston-to-head clearance tighter than 0.040-inch if you feel brave. Noted horsepower hero John Lingenfelter says that clearances of 0.037 to 0.040 inch are possible, but you must know what you're doing. The late Smokey Yunick also recommended a quench clearance of 0.040 inch as a safe but critical clearance.