PAR Con Rods

campbellju

Moderators
Staff member
I need to send my PAR con rods to the engineering shop. :x

After having difficulties balancing them the first time they were there, we've now come to building the bottom end and find the gudgeon pin doesn't really fit between the rod's little end. :evil:

Its an HKS piston but I've not heard of anyone having problems fitting them to standard rods so I'm assuming its the PAR bearing.

So, My thoughts were....
Has anyone else had problems with con rods and Gudgeon pins?
I need to find out the tolerance or float gap between the pin and bearing?

Any info appreciated as I want to get the bits down the engineering shop tomorrow.

After all the hassle the rods best never break or I may as well have stuck with standard. :roll:

Cheers,
Jim.
 

JU5TY

Member
I know of others who have had problems when balancing them! Not sure regarding fitting them, but it wont be the HKS pistons that are at fault....

Ive got a PAR gearset... enough said! :evil:
 

Jobi Joba

Member
LOOOOOOOOOOOOOOOOOOOOOOOOOL :lol: :lol: :lol: :lol: :lol: :lol:

my PAR con rods... :roll: I had to:
- machine the little end bushing cause my Tomei pin didn't fit
- machine the little end sides cause I was unable to fit my Tomei pistons on them (little end was too wide)
- balance them cause there was a 4g difference between the lighteste and the heaviest...I machined the end of ARP bolts to match the weights... :wink:

So don't worry,you're not unlucky,you've just bought PAR con rods,that's all... :roll: (but they look really really strong)
 

campbellju

Moderators
Staff member
Thanks both for the feedback. Its brightened my evening if nothing else :lol:

balance them cause there was a 4g difference between the lighteste and the heaviest
Ahhh, you must have got the higher quality items... 9g on mine!!! I like the tip on the ARP bolts, I might ask the machine shop to try again :wink:

(but they look really really strong)
You took the words right out of my mouth!! 8)
 

skiddusmarkus

Active Member
Is the gudgeon pin meant to slide in easily?Mine is a tight fit and I presumed they'd tap it in with a rubber mallet or summat?Am I just clutching at straws here?
 
S

Sirnixalot

Guest
nope....they need to be tapped in.....common practice is to put the pistons and rods in the oven and the wrist (that g word) pin in the freezer.

even then they some times need a little rubber mallet convincing
 
E

Edd

Guest
skiddusmarkus said:
PAR-helping DIY engine enthusiasts the world over.Think how much you're learing about engineering.
and realise you could have done a better effort in craft and design at school with a block of steel, a hacksaw and some wet and dry :lol: :lol: :lol:
 

skiddusmarkus

Active Member
Jobi Joba said:
yes,the piston pin is meant to slide easily...Go for sand paper if yours is only "a little bit tight"
Sand paper- :lol: that sounds very accurate.Shall I take off 1/1000 or keep rubbing until it's oval?
 

GINGA

Active Member
nope....they need to be tapped in.....common practice is to put the pistons and rods in the oven and the wrist (that g word) pin in the freezer.
The gudgeon pin should be free in the con rod thats why it has a bearing in it :wink: you might have to warm the piston slightly to get the pin to fit in them on standard pistons (from manual) but in most aftermarket pistons they will be a fully floating design held in by the circlips in the pistons.
[/u]
 

campbellju

Moderators
Staff member
:?
So what's the concensus of opinon? I know the gudgeon pin was an incredibly tight fit on the standard piston but my understanding is there still needs to be a gap between the g (word) :wink: and the rod's bearing of a small amount.

PAR-helping DIY engine enthusiasts the world over.Think how much you're learing about engineering
LOL :lol: but it is true, I probably wouldn't have given a damn about the float gap on a con rod if not for the academic institution that is PAR
 

Jobi Joba

Member
GINGA said:
nope....they need to be tapped in.....common practice is to put the pistons and rods in the oven and the wrist (that g word) pin in the freezer.
The gudgeon pin should be free in the con rod thats why it has a bearing in it :wink: you might have to warm the piston slightly to get the pin to fit in them on standard pistons (from manual) but in most aftermarket pistons they will be a fully floating design held in by the circlips in the pistons.
Totaly true. ;)

And if it's only a matter of 0.01mm for u Simon,trust me,sand paper is the only solution...
 

Nad

Active Member
PAR, nuff said. In future it will be ok if only people searched before order.

TBH u must be fitting them wrong. Thats what PAR said when everyone was having trouble with the gearsets :roll:

Nad
 
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