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| Math guys - can ya help? https://slantsix.org/forum/viewtopic.php?t=39073 |
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| Author: | WhaleMstr [ Sat Feb 20, 2010 1:26 pm ] |
| Post subject: | Math guys - can ya help? |
Since I had all the machine work done 6 years ago - I never "knew for sure" what the compression ratio is on this thing I have this apart and decided to check the fluid capacity of the head chambers and - using what I had, I found that the head chamber holds 11 teaspoons of fluid. The pistons are .060 and I was wondering if you can guestimate what the compression ratio may be with these measurements??? Don't have anything to measure cc's with so that is the best I can do - unless you can advise me of another way. I had the block decked 9000th's and the head itself was taken down just a few 1000th's so I really have no idea Thanks for any ideas Dan |
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| Author: | wjajr [ Sat Feb 20, 2010 2:44 pm ] |
| Post subject: | |
Head over to Tractor Supply and pick up a package of these babies. Get a scrap of Plexiglas large enough to fully cover one combustion chamber in your head, drill two 1/8th inch holes in it (one to inject water, one to let air escape while filling) seal it to the head with some grease, and fill the void with water. Start with a full 60cc’s and calculate the difference to find the volume of each combustion chamber. Take an average volume of the six, using feeler gages determine the average distance each piston sits down in its bore, and any over bore from stock. Than locate an engine compression calculator such as this one on line, follow the steps entering in your data. |
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| Author: | dakight [ Sat Feb 20, 2010 3:37 pm ] |
| Post subject: | |
The first link isn't working but I believe it probably refers to a 60CC graduated asperating syringe. I bought a plastic 100 ml ( for practical purposes 1 ml=1cc ) burrette for about $20.00. The syringe will be cheaper and should be available wherever veterinary supply can be found. You might even be able to get one at Walgreen's or similar. |
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| Author: | WhaleMstr [ Sat Feb 20, 2010 4:00 pm ] |
| Post subject: | |
Well, I used one of my childrens medicine cups and it shows 15ml=3tsp - which would mean that the chamber itself = 60cc's? The top of the pistons are sitting about 1/8 of an inch from the top of the deck. It's funny how someone with no money - living 23 miles from the nearest store can just go get whatever they need??? Thanks for the help D |
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| Author: | emsvitil [ Sat Feb 20, 2010 8:37 pm ] |
| Post subject: | |
A measuring teaspoon or a silverware teaspoon (which may or may not equal an actual teaspoon) ??????? |
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| Author: | dakight [ Sat Feb 20, 2010 8:59 pm ] |
| Post subject: | |
Using that method you can get an approximation but it will be a very rough approximation with a wide margin of error. Better than nothing and perhaps the best you can do in your situation but it's far from optimal. 1/8 = .125 which is probably less than your actual deck clearance. Mine was .186... I understand the no money thing; I've been there myself. Maybe there's someone nearby who could help with the tools to do a proper measurement. Good luck. |
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| Author: | WhaleMstr [ Sun Feb 21, 2010 8:38 am ] |
| Post subject: | |
Alright - guess I better explain this a little better - I keep forgetting this is the net and some do not understand me - i'm not that used to dealing with words as much as i should be. First off - when I said I used a teaspoon measurement - I also mentioned using a measuring cup. The measuring cup I was referring to comes on the top of my childrens prescription medicines and it shows teaspoon measurements and also ml measurements - and I am always praying the doctors, pharmacists, etc all know that they cannot lie to you when it comes to dosing children. SO - what I did was take the head and set it level - then I poured (I used 5wt oil) into the measuring cap until I hit 15ml/4tsp and poured that into the head chamber, it took 11 "tsps/60mls" to bring the "level" of the oil up to flush with the head deck - eyeballing it straight across. So that is how I came to that measurement I just went out and checked the pistons - top of piston to block deck - "5/32" - checked 3 of them and it is the same - 5/32's from piston top to block deck. Just a tiny bit more than 1/8" Now I was hoping that someone out there would be able to figure out what my compression ratio is based on these figures?? FIguring in the thickness of the head gasket too. I am not shooting for perfection - just a little better idea. Hope this helps a little and can make it easier for someone to figure this out for me. Thanks guys, Dan |
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| Author: | Joshie225 [ Sun Feb 21, 2010 9:44 am ] |
| Post subject: | |
Dan, You really need to cover the combustion chamber with something flat to accurately measure the volume. If you want to see why I suggest you take a guess at how many drops of water you can fit on top of a penny without spilling over then try it. Sacrifice a CD case and measure the head volume again. I bought a 60cc syringe at the local farm and feed store for less than $4. Break out a straight edge and the feeler gauges to measure the piston to deck clearance. Also, carpenter's levels are for carpenters. A machinist's straight edge will be flat to within less than .001" in over 2'. |
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| Author: | WhaleMstr [ Sun Feb 21, 2010 10:07 am ] |
| Post subject: | |
Joshua - it was flat across = no surface tension showing - am familiar with surface tension - I do not need the accuracy you seem to think I need? Just a close approximation - I am not trying to turbo this thing or anything like that - just wanted a rougher idea than - well according to what it looks like you have about 8:5 or 9:1 - figured the numbers above are close enough to get within a good ball park figure? Apparently I was wrong again and it's too hard to figure it out this way So next time I will just have to say - well I went out and got a peice of plastic - drilled a hole in it - used a syringe to fill it and I came up with 60cc's - that would probably saved me a ton of typing huh? lol Oh yeah and I checked the deck height with my feeler gages and it shows - .139 |
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| Author: | Joshie225 [ Sun Feb 21, 2010 11:02 am ] |
| Post subject: | |
You say you want to know the compression ratio, but then it's too much work to come up with a piece of plastic? Oh well! |
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| Author: | Doctor Dodge [ Sun Feb 21, 2010 11:41 am ] |
| Post subject: | |
Taking your info. listed above... Using a 3.5 diameter head gasket, compressed to .038 (FelPro) The static compression calculates to 8.258559773987729 ( 8.26 to 1) It is important to take accurate mesurements, here is why: If all else is the same and we use a .020 thick head gasket, (steel shim type) the CR will be 8.5 to 1 If we have 2 cc less in the head chambers (58cc) with the shim gasket, CR is 8.68 This is something where a little change make a big difference. DD |
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| Author: | KLJohnson [ Sun Feb 21, 2010 12:30 pm ] |
| Post subject: | |
A few conflicting measurements were given. I used 11 tsp at given cough syrup ratio of 15ml per 3 tsp for a 55ml (cc) chamber (rather than 60cc) and 5/32". Using a .045" gasket ~8.37 static .028" gasket ~8.46 static Same ball park. |
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| Author: | WhaleMstr [ Sun Feb 21, 2010 12:56 pm ] |
| Post subject: | |
Thanks guys! See - now that was easy! I was never sure just how I stood - but now have a pretty close idea. I will check it later again - using plastic and see just how close the actual cc is. Will be heading into town on Tuesday and see if I can find a pipette with ml accuracy. Then before I put this together again I will check all of them to see if they are within the same range, Thanks Doc and KL Dan |
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| Author: | WhaleMstr [ Mon Feb 22, 2010 11:43 am ] |
| Post subject: | |
okee dokee using plastic and a new measuring tube they hold 57ml of fluid and a recheck with feeler gauge shows .139 again uh - guess this thing keeps getting more performance out of it every time i check it - lol if i just keep rechecking it i should have a super high perf rig before the day is out!!! hahaha thanks ya'll felpro's due in tomorrow dan |
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| Author: | wjajr [ Fri Feb 26, 2010 5:57 pm ] |
| Post subject: | |
Me quoting me: Quote: Head over to Tractor Supply and pick up a package of these babies. Get a scrap of Plexiglas large enough to fully cover one combustion chamber in your head, drill two 1/8th inch holes in it (one to inject water, one to let air escape while filling) seal it to the head with some grease, and fill the void with water. Start with a full 60cc’s and calculate the difference to find the volume of each combustion chamber. Take an average volume of the six, using feeler gages determine the average distance each piston sits down in its bore, and any over bore from stock.
For some reason unknown to me, "Babies", link won't pull up. Here is the address for your copy & pasteing pleasure:http://www.tractorsupply.com/livestock/ ... k--2286830 This should bring up a twin pack of 60cc syringes for $2.99 |
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