Practically Classics Forum

....the main and big end shell bores. Has anyone experienced this. On a Ford i4 dohc and using Glyco new shells,the main cap bores with shells measure 54.78mm whereas the journals are 54.93mm. Same as the bigends which the bores measure 50.30mm,the journals measure 50.85mm. Your opinions mostly appreciated

I wonder if these are for engines that have been re bored as they seem if my maths is right 6 though over and 21 ish thou over?

thanks for your reply Mega.... 54.93mm minus 54.78mm = 0.15mm, which in old money is 0.005905512in. Several weeks back,I took it to a local engine builder to do what's needed to get the crank turning. He put it down to me,for putting the wrong main caps on. Which did get me thinking that I did put the wrong caps on,which came off a 2 litre i4 dohc that I stripped to use the crank on the 2.3 i4 dohc that I'm building. Having located the correct caps off the 2.3,which are being used on the existing engine build. The caps aren't the issue,as both engines are identical,just the bore size.

Like Mega, I wonder if the shells are undersizes for re-ground cranks, although they seem funny values, I always thought they went in steps of 10 thou. What are the markings on the shells. Your engine builder ought to know.

sierra3dr wrote:Having located the correct caps off the 2.3,which are being used on the existing engine build. The caps aren't the issue,as both engines are identical,just the bore size.

That's true if the caps are aligned correctly. If they were line bored the mismatch may be one or more is slightly offset on the block and this is causing the crank to lock/jam.

suffolkpete wrote:What are the markings on the shells.

The markings are STD,and main shells have 2mm wall thickness using a vernier caliper,but precisely measure 2.139mm as per Glyco specs

Well,here's a surprise. I've decided to use King bearings and the crank turns by hand.....