cd.thomson
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| posted on 3/12/08 at 09:03 PM |
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pistons in my pinto
Good evening!
I've currently got two pintos sitting in my garage. One complete 205 block which will end up sat in my Dax and another 20 short block which has
had a noticeable amount of reconditioning although I have no idea of specific details (It would appear that its never been turned over since the work
was done).
Enough of a preamble though, I don't have callipers and have just spent the evening working out the diameter of the pistons to figure out if
they are oversize. They appear to be a little under 92mm. There are markings on the face of the pistons. Could these be used to check for sure?
edit:- by a little I think fractions of a mm, however I used inaccurate methods (piece of string to find circumference then calculating from there and
using a transparent ruler to find the widest straight line through the face)
[Edited on 3/12/08 by cd.thomson]
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Thinking about it
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| posted on 3/12/08 at 09:11 PM |
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If the piston is over size it will have some indication on the top.
The ones I am about to fit are marked.020". Look for something like.
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cd.thomson
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| posted on 3/12/08 at 09:16 PM |
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the details on the pistons are as follows:
SP 0.025
92.285B
18755 +1.5mm
R42 PM15
2OHC
Hoping the "92.285" indicates the precise diameter?
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Thinking about it
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| posted on 3/12/08 at 09:21 PM |
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Just looked in the book.
standard 90.8
1.0 over size 91.8
so Iguess 1.5 over size or 60 thou in old money.
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cd.thomson
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 posted on 3/12/08 at 09:29 PM |
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Thanks thinking about it.
Looks like I'll be paying £80 to get the engine rebored, and fitting lovely new pistons, conrods and crank.
I'm well chuffed, originally I was going to run the engine standard, and now I have the parts to make a 2.1l running a kent fr32 cam and
2x40dhlas.
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delboy
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| posted on 3/12/08 at 09:45 PM |
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There is nothing really wrong with the 20 block, the 205 is a little better, however, if your 20 is already bored out and fitted with th new pistons
etc, why dont you use it with the head from the 205 which if it's an injectin engine will flow a little better. It will save you the cost of a
rebore and give you a spare engine ready to be re bored if you ever need it.
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cd.thomson
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| posted on 3/12/08 at 09:53 PM |
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quote:
Originally posted by delboy
There is nothing really wrong with the 20 block, the 205 is a little better, however, if your 20 is already bored out and fitted with th new pistons
etc, why dont you use it with the head from the 205 which if it's an injectin engine will flow a little better. It will save you the cost of a
rebore and give you a spare engine ready to be re bored if you ever need it.
Hmm I hadnt thought of this, I suppose because I have read that the 205 block is a better base for a performance engine. Also I'm a little
daunted by the fact the 20 block has absolutely nothing on it, will everything swap across?
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02GF74
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| posted on 4/12/08 at 10:28 AM |
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Both blocks are perfectly adequate for marine mooring purposes. 
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cd.thomson
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| posted on 4/12/08 at 10:41 AM |
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constructive you ain't
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flak monkey
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| posted on 4/12/08 at 11:15 AM |
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The 205 conrods are much stronger so there are benefits to using the 205 block (they will sfaely take 7300 rpm as opposed to 6500 on the 20 block) but
to benefit you would have to swap the pistons on the rods, not a problem if you have access to a press though.
The 205 block does also have thicker walls in the bores so is a stronger block when it has been over bored. However the 20 block will take being bored
out as shown by the one you have....
David
Sera
http://www.motosera.com
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