Engines...

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Engines...

Post  Admin on Sat Apr 18, 2009 12:20 pm

Engines.

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Re: Engines...

Post  Admin on Sat Apr 18, 2009 12:22 pm

Head info
Submitted by dwc43, written by Charles Sanborn a reputable late model dirt track racer from Shelbyville,Tn.

I can across a folder of flow bench tests of various cylinder heads. Many tests go back to 1989, a few are later. All the numbers are consistent @28" of water column. All are with intake manifold---generally ported intakes. All are at .600" valve lift---many heads flow well at higher lifts but back in the "dark ages" we only used valve lifts of .600" or less. We are a little more ambitious today(about valve lifts).

1. Stock 906 BB heads/stock valve work---201CFM (I)---130CFM (E)
Valve sizes were 2.080"/1.740". This would be considered as "out of the box". We also flowed a set of 452 heads and the flow numbers were almost exactly the same. The intake port actually "stalled" @.550". (1988)
2. We "pocket ported" the set of 906 heads, gave it a 3 angle valve job and just "knocked off the rough stuff" in the ports. Flow improved to---217CFM (I) and 159CFM (E). The port no longer "stalled". (1988)
3. We had a set of Valley Head Service 452s from the 70s. Valve sizes were enlarged to 2.19"/ 1.88". These ports were really pretty. The flow numbers were---263CFM (I) and 177CFM (E). The exhaust ports were wide and short---as was popular back in the 70s.(1988)
4. I ported the 906s with what I considered a "full blown port job". Installed 2.140"/1.810" valves. The flow was 260CFM (I) and 180CFM (E). The exhaust port retained almost stock width and was slightly raised and roof rounded--- a later design.(1988)
5. Got another set of 906s, went all out with the port work. Used 2.19"/1.88" valves. Milled them down where the combustion chamber was almost "closed". These heads really worked---281CFM (I) and 184CFM (E).
(1989).
6. Got one of the first sets of Stage VI heads. They looked like junk when we got them. They ended up working pretty well. Valve sizes were 2.14"/1.81". Flow was 303CFM (I) and 206CFM (E). The exhaust ports were "D" shaped. At the time I thought the port work was pretty radical. I am sure the flow numbers would be better today with the offset rockers, better valves, better intakes, etc. available.(1993)
7. In 1992 we got into the small block engines for competition. We used a set of early W2s, 2.020"/1.600" valves, "stock" ports but throughly prepped. Flow was 258CFM (I) and 191CFM (E).
8. We also had a set of early ported W2s prepped by Automotive Specialists for Harry Hyde for use on the K&K Dodge back in the late 70s. These heads were serious---flow was 304CFM (I) and 206CFM (E). Valves were 2.080"/1.600". The ported intake was very nice also. Notice the small block heads worked better than any of the BB heads.
9. Almost forgot---flowed a B1 head---out of the box it flowed 284CFM (I) and 205CFM (E). This was "as cast", and could have been much better when properly worked. This head was really designed for very high lifts.
10. As a point of reference a set of Brodix#9 GM heads w/ 2.15"/1.625" valves flowed 254CFM (I) and 169CFM (E).
11. Our first set of really serious race heads---Arringtons. Joey had these cast for TransAm competition and these were the first aluminum heads used in Nascar truck competiton. Valves were 2.100/1.585". The intake ports were raised 1.00", exhaust was raised about 3/8". These were hand ported. Flow was 332CFM (I) and 229CFM (E). These heads also had a high rise intake manifold(ported).(1995)
12. Our first set of CNC ported W7 Chapmans. Flow was 340CFM (I) and 242CFM (E). Valves were 2.150"/1.625".(1995)
13. Our first set of W8s, Chapman CNC ported. 2.180"/1.625". Flow was 358CFM (I) and 264CFM (E).(1999)
14. Our best set of W8s---Arrington CNCd. Flow is 374CFM (I) and 264CFM (E).(2001) All of the W7s and W8s require a serious ported intake to match the heads. All the W7s and W8s really flow much better at higher lifts than .600".
15. Now back down to earth! A later style 18 degree W2 head with 2.055"/1.600" valves, fully tricked(no porting) flows 274CFM (I) and 196CFM (E).(1993)
16. Finally, 15 degree W2s, fully tricked, no porting flow 286CFM (I) and 205CFM (E).(2002)

These are all the head types I have used. No "X","J", etc.

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Tips for first engine start up.

Post  Admin on Sat Apr 18, 2009 12:41 pm

1: Make sure you have oil in the engine. I know this sounds stupid, but I've seen people get in a hurry...

2: Double check that ALL fluid levels are good.

3: Prime the engine with said oil. I use 10w30 for initial start as it allows quicker oil pressure at start. When priming with oil make sure and slowly turn the engine over by hand at least two complete revolutions. You want oil through-out the entire engine.

4: After priming with oil reinstall distributor and drive gear. Make sure engine is at T.D.C.

5: Set the points/magnetic pickup then rotate the engine so the timing mark reads 10 degrees BTDC. Then turn the distributor so that the reluctor is directly opposite the pickup coil. If points, turn the dist. opposite the engine rotation so they are just open.

6: Make sure the battery is fully charged, and check all your fluid levels and connections one last time.

7: Pour a small amount of fuel into the primaries. Turn the idle speed screw in about two turns. Install air cleaner assembly in case of backfire.

8: Set your air mixture screws out two turns to get it in the ballpark to run.

9: Have a helper start the engine for you as you watch for any sign of fire (you do have a fire bottle don't you?) or major leaks from engine. Set the timing to 35 degrees with the vacuum hose off when it starts. Run the engine at 2500 rpm for at least 10 minutes. Then back it down to 1500 rpm for another 10 minutes.

10: Shut the engine down and allow it to cool down. Check engine oil level, and all fluids. Look everything over with a critical eye.

11: Set your idle speed, timing, idle mixture screws, etc...

Note: I alway's change the oil and filter after the initial 20 minute run, and then again at 100 miles. Anal? maybe, but I haven't had an engine related problem with any engine that I built.

And if it doesn't start quickly within the first few revolution, find out why and correct it before you wear all the lube off the cam.

You can fill your float bowls with a squeeze bottle then re-attach the line.

Be sure when your at TDC that both valves on #1 are closed.

Triple check and double check again the firing order on the cap.

Have a water hose ready in case you need to cool her off during the break in.

If it's a solid lifter engine I'd extend the break-in to 20-25 minutes at minimum of 2500 RPM.

One thing I use plain water to start up, just in case you have a leak, you don't put anti freeze in your engine. Antifreeze will destroy the bearings and wipe all the coatings off of a new came and such. I would also put an old stocking over the radiator outlet then slide the hose on & tighten, reason being it catches all the junk that comes loose inside the block from getting into your radiator. I take it off a day later and you should see all the junk it catches.


One last thing...do NOT get into a hurry! Take your time and do it right the first time.

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What is detonation and how to fix it.

Post  Admin on Sat Apr 18, 2009 12:54 pm

Detonation.
The terms dieseling, ping, knock, run-on, detonation and pre-ignition are all basically the same condition.All of these conditions are caused by the fuel igniting through heat and compression before the piston reaches the optimum firing position and allowing the plug to ignite the fuel.

Common causes:

1. Poor fuel.

When we talk about High octane we're referring to SLOW burning or explosive resistant fuel, the higher the octane the slower the burn. So to make an extreme comparison let's use 92-octane premium on one side of the scale and compare it to alcohol which if guessed at the octane rating I would say 200. You can pour alcohol on your hand and light it on fire and almost blow it out without burning yourself (don't try this at home) so using this comparison the lower the octane the more unstable and explosive the fuel, hence when you heat it in a combustion chamber and compress it it's going to ignite quicker than a high octane fuel.

Cure: Higher octane fuel

2. Combustion chamber quality

The combustion chamber in your cast head is rough and full of imperfections. Each one of those tiny bumps caused from the sand casting are potential causes for detonation. As the engine goes through a combustion cycle those little high spots become red hot as the fuel is injected by the valves and it's heated. As soon as the cylinder pressure reaches a certain point...BOOM the fuel ignites...Ping....

Cure: A higher octane fuel can help in most cases. Allot of this problem can be corrected by carefully massaging all the imperfections out of the combustion chamber with a dye grinder and a box of rotary sanding discs. I like to polish a combustion chamber at high speed with a final grit of 100-150 then come back with a piece of wet paper at 300 grit. I also do the same polishing on the piston tops and have them thermal coated. You'll be amazed at the HP gain and reduction in detonation.

3. Combustion chamber temperature

If the combustion chamber is just too hot the same thing will happen as in #2, the fuel explodes from heat and compression.

Cure: Reduce the overall head temp by installing an aluminum radiator, improve radiator efficiency or improve the cooling characteristics of the head.

Your plug heat range is basically the amount of heat that the plug holds after the instant of combustion, so the hotter plugs will hold more heat and could cause detonation on the next fuel charge just like an imperfection in the casting. If this is causing your problem then a colder plug is in order. I like to keep trying colder plugs until they foul and go up one range.

4. Lean condition

A lean air fuel mixture can be catastrophic as the engine leans out tremendous heat is built up and can actually cause the piston to melt. As the mixture becomes lean it contains a higher mix of air, which is the oxygen source, the more oxygen the hotter the flame.Think of a cutting torch. it works exactly like that. Of course this is an extreme condition usually only experienced in a racing application or in street engines with maladjusted or incorrectly jetted carbs. Don't confuse this with lack of mixed fuel or too small of a carb, we're talking about air/fuel ratio not volume. I want to add here that this condition can happen in your street car if your fuel pump is junk and it runs out of fuel at the top end at WOT.....which is why I always run a fuel pressure gauge where I can see it and not buried under the hood somewhere.

Cure: Careful adjustment and balancing of the carb through the idle-primary-secondary circuits and carb jetting.

5. Ignition timing

If the advance curve is not set for low octane explosive fuels like they force us to run these days your advance curve may not be coming in at the right time causing the plug to fire before the piston reaches TDC and because the fuel is explosive and doesn't burn like a higher octane fuel it's all done before the piston reaches it's optimum firing point. This is pretty common on our old cars, after all 92 octane used to be regular and 102 was premium.

Cure: Switch over to electronic ignition and have the distributor curved for the type of fuel and compression ratio you have. The type of driving your going to do will affect the curve also....such as pulling a trailer or WOT drag racing.


So your ready to get to work, pull the heads and clean up the combustion chambers, install a 180 thermostat, have the radiator cleaned, use good fuel, get a good carb and adjust it correctly get that distributor dialed in and ...Drive it like you stole it!

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The engine in action showing all 4 cycles

Post  Admin on Mon Mar 22, 2010 1:55 am

Here's the engine in action showing all 4 cycles of intake,compression,power, and exhaust.


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Valve spring and valve float

Post  Admin on Mon Mar 22, 2010 2:12 am

What you are about to see is a video of valve spring and valve float. You can here the operator calling out the rpms as he turns up the speed on the spin tron. The flashes are the strobe light on the high speed camera and that's what stops or slows the motion so the camera can pick it up.


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Re: Engines...

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