MKII SQ4 IMD pistons to Club con-rods

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MKII SQ4 IMD pistons to Club con-rods

Postby daveleek » Thu Mar 21, 2019 10:34 pm

What is the best method of getting the correct clearance of the IMD piston gudgeon pins to the Club con-rod small ends, reaming or honing?
If reaming is satisfactory can I do it by hand, if it's honing, it's off to the machine shop again.
Can anyone advise me?
Cheers, Dave

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby bob cottam » Fri Mar 22, 2019 6:17 pm

HI Dave- not sure what you mean here? I fitted the IMD pistons and club rods. I had no issues with gudgeon pin fits at all.....Runs fine, Bob C

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby dave.owen » Fri Mar 22, 2019 6:46 pm

Same with mine, no honing required.
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Re: MKII SQ4 IMD pistons to Club con-rods

Postby daveleek » Fri Mar 22, 2019 8:22 pm

Hi ,thanks were they a push fit? did you warm the rod up , I dont have precision measuring tools ,so I cant take accurate measurements ,all I know is its not gonna go ,I will have another look tomorrow ,Dave

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby paul_turner » Fri Mar 22, 2019 8:26 pm

possibly the people who answered had them some time ago, I have heard the recent batch do need reaming/honing, probably best to give Bruce a ring and check.

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby daveleek » Fri Mar 22, 2019 9:04 pm

Thanks Paul ,I have been able to measure the small end =0.6605 small end size should be 0.6865 , one consolation ime not the only one . What would Bruce do if I contact him ,tell me to hone them I suppose ,can I do it myself , would an adjustable reamer be suitable .What would be the approximate cost of a +040 rebore for a square 4 in the UK ,ive had mine done this week in Holland and I allmost fainted when I got the bill , I wont be going back there again , thanks , Dave

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby daveleek » Sat Mar 23, 2019 10:39 am

I talked to Bruce this morning , use an adjustable reamer and use paraffin as the lubricant , I had the cases together when I discovered the discrepancy, and I can do the reaming without having to split the cases , phew .

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby paul.jameson » Sun Mar 24, 2019 9:47 pm

Look on Ebay for a suitable secondhand reamer, preferably made by T&J (Taylor and Jones). These reamers are much higher quality than the new ones made in India and you can get them pretty cheaply, with a degree of patience. I have equipped myself this way and whilst some purchases have been disappointing, the majority have proved to be excellent value for money. You can also get new cutting blades from T&J but they do know how to charge if you order a set.
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Re: MKII SQ4 IMD pistons to Club con-rods

Postby daveleek » Sun Mar 24, 2019 10:40 pm

Thanks Paul,Ive got a reamer on its way from Uni-threads,I suppose for the price it will have been made in the Far East , you are right about T&J ,It would give me a better chance of success ,I feel a little let down receiving the club rods requiring reaming or honing when my gudgeon pins are the correct size , so everyone who have bought a set of the same batch have the same problem as me , I read the prefitting checks, my pin is 0.6855 and put the cases together , I only have one shot at each rod .

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Re: MKII SQ4 IMD pistons to Club con-rods

Postby john.whiting » Mon Mar 25, 2019 3:07 am

I would doubt an experienced fitter could ream .026" freehand from a small end bearing and avoid bell mouthing and alignment problems.........and someone who has never done it will surely strike chatter on the first cut....................hand reaming of small end bearings is always done in a fixture that guides the reamer and holds the rod or piston..............I would suggest you pull the rods ,and either get the maker to rectify,or if not possible,take the rod to an auto machinist and have the job done in a proper pin fitting machine.....IMHO,.026 " is too much to hone.,even on a machine with a guide arbor...............I might add,stories of hand reaming belong with old fashioned Ford flatheads,where rod bearings/pistons were aligned by bending the rod.......this was common practice in engines once,all the old Harley manuals have details of rod alignment by bending.


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