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TR2/3/3A if it is 86mm or 87mm.

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sp53

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Well I am ordering parts for my cam replacement and because I bought this car as an unfinished restoration with parts, I am not sure if the pistons are 86mm or 87mm because they came with the car out of the box. So how do I tell the difference for the 1mm when the pistons are in the car? I think I have a caliper that opens to that size, and I could measure the piston top in the block, kinda, but is there others ways to know if it is 86mm or 87mm.

Thanks Steve
 
I went through this. I really think I was unwilling to trust any method other removal of a piston. I wanted to install 87s anyway, and it made no difference since I was installing new pistons and liners. But I do recall there being no issue when I measured. I couldn't reach a comfort level on top of the block, and I couldn't find any stamping.
 
Thanks David I sure hope I can see that well. KVH I am leaving the pistons in the block and I am happy to hear someone else had this problem. I saw the problem when I went to order the gasket set. I thought 86 and 87 used the same gasket, but I guess not. I probably got the head gasket correct when I built this engine 5 years ago.

Now I am thinking take the head off and use the old gasket as bench mark. Even if I have the wrong one on there, I should be able to figure something out. I guess it is time to get started pulling the head. I will get back about that because I used some of the head gasket paint to make sure of the seal. I guess it worked, but will it come apart????

Steve
 
You could try the rope trick. I hear you slide it into a plug hole then rotate the engine by hand. Fat rope.
 
Thanks KVH I am probably going to need the robe trick for the first time. I am in such denial that the cam shaft fail that progress is slow. I would think at my age reality should be evident.

Thanks Steve
 
If you are just replacing the camshaft, why do you need to know the cylinder diameter? Are you redoing the whole engine, or replacing rings, or...?

In any case, measuring the cylinder diameter should be simple, as long as you really have a stock diameter. Some of these cars (like mine, for example) have had rebored cylinders, even though they are replaceable. Doesn't make much sense to me, but it's done.
 
I hear you Steve; I guess the 86mm and 87 mm take different head gaskets. I almost certain this engine is an 86 mm because the piston had 4 rings. The project probably set since 1980, so probably 86mm. I guess it is even possible they are 83mm. If they are 83mm, then I am sure I can see that, and like David suggest, I should be able to tell the difference from 86 to 87mm. I did get started on the tare down, so with some luck I will be able to post some pics.

Steve
 
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