May 7, 2016 at 1:43 pm #236120
Some of us, when we buy our cars, wonder what cc engine is installed. The seller didn’t know. And you don’t want to pull a head off just to find out.
So,… get an old small party balloon, a bucket of water, an old spark plug, a graduated pitcher from your kitchen.
1. Knock the ceramic and electrode out of the old plug such that you can blow air through it.
2. Remove all 4 spark plugs.
3. Attach the balloon to the spark plug you prepared in step #1.
4. Put 5-6 inches of water in the bucket. Mark the water level with a magic marker.
5. Turn the engine until #1 cylinder is at BDC (bottom dead center).
6. Screw the plug and balloon into #1 cyl spark plug hole.
7. Slowly rotate the engine to bring #1 fully up to TDC.
8. Tie off the balloon to capture air.
9. Immerse balloon fully into the water keeping it under water and mark the water level on the side of the bucket.
10. Remove balloon, now fill the bucket from your first mark to the second mark noting how much water it took.
11. Multiply by 4. That should be your actual approximate displacement.
Of course, there are ways to make your rig a bit more elegant, but assuming that your engine is in good condition, I can only think of one reason why this should not work, but I will leave it to Ed, Paul, Kent, Allen and whoever else to debunk this procedure.May 7, 2016 at 9:59 pm #268011edward ericsonParticipant
I don’t see why that wouldn’t work, so long as the valves and rings seal well.May 7, 2016 at 10:17 pm #268012greg pressParticipant
Royal , You are one of the biggest reasons why before I go to bed at night I have to log on to td replica .May 7, 2016 at 10:47 pm #268013secretagentcatParticipant
Knowing that this country has people as smart as Royal is the reason I sleep peacefully at night; Now if we can just get him to run for President!May 8, 2016 at 8:19 am #268014Dale SchumacherParticipant
He has the tendency to blow stuff up so be careful about having him run for President – wait – that might be a good thing.May 8, 2016 at 8:58 am #268015
Schu, Shhhhh! Your memory is TOO good.May 8, 2016 at 5:19 pm #268016secretagentcatParticipant
Laughter through smoke is my favorite emotion!May 8, 2016 at 7:50 pm #268017BobParticipant
@lrhRoyal wrote:I can only think of one reason why this should not workAir being compressible and water is not…? Would lose a little amount of volume in the procedure I guess.I was thinking maybe oil in place of air but then you would need to stand the engine on its side to do that. So I like your way instead.May 8, 2016 at 8:36 pm #268018newkitmanParticipant
Check this month’s issue of Hot VWs. They cover that in the reader’s section.
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackMay 8, 2016 at 9:45 pm #268019newkitmanParticipant
I should have mentioned that the method used in the Hot VWs magazine was NOT Roy’s method. That person used a stick in spark plug hole and measured TDC and BDC. That and some other methods. I’m annal and use the tear the engine down and start from scratch method. Roy’s is way easier.
VW based 53MGTD - "MoneyPenny"
"If one thing matters, everything matters" - from the book The ShackMay 9, 2016 at 7:23 am #268020edward ericsonParticipant
OK, so the stick will tell you the stroke, but you’d have to know the bore too.The compressibility of the air is going to be a factor, but you’d also have the combustion chamber volume and compression ratio to contend with.I am thinking Roy’s Balloon method would not tell you the difference between a 1905 and a 1915 cc engine, but it should be able to tell you whether you’ve got a 1600 or a 1776.May 9, 2016 at 7:47 am #268021
I agree Ed, “My” method will not tell a 10cc difference. (One would have to be careful measuring, since a 10cc difference in engine displacement would really only show a 2-1/2cc difference on the water level in the bucket.) But it will/may give an idea of what jugs are installed.
As I recall, you thought that your old SP engine was a 1300cc, but were never really sure.
This would have resolved the question.
At first, I thought that a small balloon would be what you wanted, but have been tinkering around with it and now believe that a big one is better since the air inside would not have to be under much pressure. I’m still working on it, I expect that my method will read slightly low since when you immerse the balloon in the water it will slightly compress the air inside it. And of course, all the numbers would be low if you had bad valves or excessive wear on the rings.May 10, 2016 at 7:46 pm #268022KentTParticipant
Let’s combine Roy and Allen’s methods… Tear it down, measure everything, then rebuild it with this.
Seriously, I think Roy’s method would differentiate between a 1776 and a 1600. Not sure if it’s precise enough to get within 100cc though. 1500 or 1600? 1776 or 1835? 1835 or 1915? Etc. You’d definitely have to measure a known one for a baseline..KentT2016-05-10 19:49:58
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