Friend of mine was doing an oil change this afternoon on his 24 touring, and decided to pull the pan and have a quick look inside.
Because I am the nosey type, I wanted to have a look too. He put this one together last fall, and it runs fine. I broke out the flashlight and had a good look up through the bottom, and noticed that the slots on his aluminum pistons are on the camshaft side. I asked him why they were backwards.....he told me that as long as the pinch bolt is on the cam side, they are fine.....
Someone want to shed some light on this for me? Is this going to cause him grief later on?
Yes, there is a right and a wrong. Some piston manufacturers make it clear which way they should go. However, the real right and wrong has to do with which side of the piston takes the thrust on the power stroke, not which side the cam is on. In a previous discussion, it was found that some piston manufacturers actually recommended the wrong way. The truth is, it doesn't make a huge amount of difference. Especially in a model T. In a high power race car, it would.
Drive carefully, and enjoy, W2
Wayne is right, we have debated this before, some engine manufactures do fit skirt split to thrust side but it needs to be the right one, so as it happens, new T pistons are.
T slot, FIG 47c, middle left.
Some that fit pistons to minor thrust side are, Reo, Packard and V8 Ford since 1944
Reason given in old school tech books is,
"These engines run quieter with the piston split assembled in reverse way to general practice"
Thanks for the info guys.
Sorry, should say "Some that fit pistons split to the major thrust side"
split to the cam ... or was it split away...bugga. now l've forgotten ...
You Guys are all smoking your socks on this one.
Pick up any Motors Manual and all the engine brands tell to place slot away from cam.
Boys, the slot does not have anything to do with piston noise. The only thing that will cause piston noise, is to much clearance, and rod alignment.
However, the real right and wrong has to do with which side of the piston takes the thrust on the power stroke, not which side the cam is on.END QUOTE
Wayne, you have to understand that the side that has the most thrust, is the cam side.
The slot in the piston is there for expansion of the Aluminum that heats faster then the cast block. When you put slots in the Aluminum pistons, the slots make the pistons weaker on that side, so you put them on the side with the least stress on the slot.
To say in a Model T, it doesn't make any difference, is just plain wrong.
I have never done, or read, or seen anybody say the slots go the the thrust side, or cam side of the block.
I don't think you were much help to answer the question,
Is it going to cause him grief later on?
First, you quote 'pick up any motor manual and all engine brands tell to place slot away from cam' 6cly
Fords have the cam on the right side making the slot facing the cam.
As for the noise factor, I can give you the details for the biggest Technical division in the Southern Hemisphere, Repco engine group, and you can argue with there publications on that if you wish.
No one claimed that it was right to fit the slot to the thrust side on a model T, just that other engines have.
So the question still remains, you as a engine rebuilder, have you seen any consequences of long term running with a piston the wrong way round in a model T engine?
I don't think you were much help to answer the question,
Is it going to cause him grief later on? END QUOTE
Well Kerry, doesn't: To say in a Model T, it doesn't make any difference, is just plain wrong. END QUOTE, say that?
My mistake Kerry, I thought this was a Model T forum, not a six cylinder Ford engine with a design not constant with Model T's. So one has nothing to do with the other.
So the question still remains, you as a engine rebuilder, have you seen any consequences of long term running with a piston the wrong way round in a model T engine? (END QUOTE)
How long it will last, who can say. But I did stay at a Holiday Inn last night!
It would be like saying how long would dippers turned backwards last, probably a long time on a Model T. but not a mile on a 216 Chevy.
As for the noise factor, I can give you the details for the biggest Technical division in the Southern Hemisphere, Repco engine group, and you can argue with there publications on that if you wish. (END QUOTE)
Ya Kerry, send me all the Model T articles out of your Publications!
I would say the bottom line here is, if someone wants to run there engine that is assembled wrong, have at it, it won't be me that has to pay the bill.
But reading your posts Kerry, trying to make an argument for a wrong assembly you must approve of it being OK!
Personally, I think all this use of the term "the cam side" should be eliminated. I think it's really pretty simple without that term. The slots should NOT be on the thrust side of the cylinder,.....PERIOD! And anybody should be able to figure out which side of the cylinders is the thrust side, simply by the direction of rotation of the crankshaft in any engine.
If it were mine, I would leave them alone until such time as I needed to take the pistons out such as for re-pouring the rod bearings or re-ring, and then when you put it back together you can turn them around. I have seen them both ways and the engines seemed to run fine.
You may notice, that in my earlier response, I didn't say which way the piston goes. That is because a long, long, time ago, I discovered that I was given the wrong directions based on slot and cam side (wasn't a model T). I have, ever since, simply visualized the rotation and stroke like Harold S says. I try to not remember the slot/cam thing.
While I agree that it would be a good idea to turn them around and do it right, modern pistons are usually tough enough that they would probably work okay backwards for a long time in a T. In a T, there isn't a huge difference between the thrust on the power stroke and all the others including the compression stroke which has the second highest side-thrust and is on the opposite side of the piston. However, Herm is also right. It would make a nice weekend day project to turn the pistons around. It often is nice to know that things are the way they should be.
Drive carefully, and enjoy, W2
The reason I said what I did, was that the rings have already seated in the present position, and it would be a bear to remove the wrist pins to switch the rods around with the pistons in the engine. So just wait until they need to come out for some other reason. You would also need to buy another head gasket if you were to pull them out from the top.
I'm sorry you think it's a mission for an argument, I was thinking more on the line of answering the post, model T forum it is but a later design and after market part.
When this topic comes up, we all know your stand on it, should be fitted per instructions and saying 'it's just plain wrong' is an answer?
'Is this going to cause him grief later on' is the question.
As no one as posted that a piston has failed them because it was in backwards in a model T is what we are still looking for.
Now, posting examples of engines with 3 times the HP and twice as many revs, that have there own reasons fitting a particular type of split skirt to the thrust side with no consequences, I consider of some help to question, owner can make up his own mind to if he is playing roulette with his engine.
So as to the OK, is still what the post is looking for because no one has said different.
So can you not remove the rod cap and twist the piston 180 degree? If you are not running dippers does it make a difference? If you crack a piston because the split is on the load side you will not be happy. Scott
Apparently the 24 touring has run many miles with the slots turned the "wrong" way. My money says it will last the owners lifetime before it fails.
Just to display my own ignorance:
I know it is common practice for piston noise abatement to have the piston pin offset from the piston center line. I don't know if this was done in Ts or by any present suppliers of pistons for Ts, but if it were, it would be important for noise considerations, but not for durability, which way the pistons are installed. I thought common practice was to have an arrow on the piston top that should point to the front of the engine.
The problem in turning the rod 180 degrees is that then the bolt will be on the wrong side! Gregg, take a look at the bolt at the top end of the rod next to the wrist pin. It should be toward the camshaft. If it is away from the camshaft, you could do as Robert says, but if it is already toward the camshaft leave it alone until you are ready to re-ring the car because you will need to pull the pistons to correct it.
Leave it alone as long as it's running o.k.
Turning the piston/rod may mess up the fit that the rings currently have with the bore and will not necessarily result in a good bearing fit with the crankshaft, (although theoretically it should). The fact that it would put the wrist pin clamp bolts on the wrong side would not concern me. (While there is a "right way"/"wrong way" to position the clamp bolt, I've never heard of a problem caused by doing it the wrong way and suspect that many hundreds of engines have backwards clamp bolts.)
My Grandfather ran a garage from around 1918 till 1948. He told of a che$y coming in with a rod knock. The customer went across the street to have lunch and his car was running when he came back. Dropped the pan or cover, pulled the piston and ron down till he could remove the nut, push the wrist pin over and put the new rod in. So can that be done with the T? Didnt folks carry spare rods with them and do that? Turning the piston should not move the rings as they are tight with the cylinder walls and loose on the piston. That should make everyone happy and the head can stay on. Scott
Scott, it can be done. I just did that exact thing to a customer's T a couple of weeks ago. The pistons were in backwards, so I pulled the rods down, removed the pins and turned the pistons around. Worked fine. The motor didn't lose compression or smoke, so I assume the rings didn't turn or somehow get upset by the process.
It doesn't make any difference which way the wrist pin bolt goes for operation, just as long as they are one way or the other for future reference of assembly, or disassembly.
I have always put the bolt to the split skirt side.
The pinch bolts are on the cam side. I was talking to him again today, and he told me that if it bothered me that much, I was more than welcome to come and change it.....
Looks like it will be running as is until it needs to come apart for something else.
Thanks for all the info guys.
I think that's a good idea to leave it alone for now Greg. See my post a couple months ago. "I screwed up my engine". I'm not saying the rods cannot be removed from under, but you are working against gravety through the small inspection plate and the bolts are way up inside the pistons with the crankshaft between you and the piston. All it takes is to pull one down too far, ahd your engine will also be "screwed up".