Looking up the values in an older TRW catalogue, the pin height for the 272/292/312 car engines are all listed as being at 1.777”.  With this in mind, I measured a +0.040” piston I had sitting here and it is right at 1.777”.  Upon measuring a stock piston, I came up with 1.782” which falls in line with replacement pistons typically having a raised pin to either compensate for increases in compression ratio that comes about by making the bores oversize or any machining that is performed on the decks during a rebuild.

 

Here’s the link to John Mummert’s site which also gives the various Y-Block dimensions.

 http://www.ford-y-block.com/dimensions.htm

 

Lorena, Texas (South of Waco)

Hi, can anybody please tell me the piston pin/compression height for the standard Y? cheers Pete 

Pete, one of the Aussie mob. Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390

Thanks for the detailed information Ted, yes the Mummurt stroker kit is very appealing, lusted after one for a while, but with the $ exchange rate it is about $2,400 AUS and there is still freight to be added. It would be the sensible way to go and save a lot of running around. cheers  Pete 

Pete, one of the Aussie mob. Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390

Hi Peter, Welcome to the site.

 

As Glen suggested, going with one of John Mummerts stroker kits would simplify things quite a bit.

 

Offset grinding will automatically reduce the journal size which requires a different connecting rod.  Some of the options on offset grinding for the Y are to grind to a 2.100”, 2.000”, or 1.889” journal.  The 2.000” journals for the Y seem to be the norm for any kind of significant stroke increase over stock.

 

As long as you’re using custom pistons, almost any available scrub (SBC) 2.000” journal rod will work for you.  Eagle has quite a selection of H-Beam rods in the aforementioned 2.000” journal size ranging from 6.125” to 6.300” long with the pin bushings being sized for the 0.927” wrist pin.  The 0.940” scrub rod big end width would need to be trimmed down to accommodate the Y-Blocks journal width with the majority of this material needing to be taken off of the inside rod face rather than the crankshaft journals radius side.  A small amount of this additional width can be taken up by doing some widening of the crankshaft journals while doing the offset grinding.  If offset grinding the 272/292 crank to a 3.48” stroke with a 2.000” journal, then a 6.200” scrub rod with the piston pin itself being in the stock Y location is doable with a small amount of machining to the block deck being required to get back to a zero deck clearance.  You’d still need to use a 0.927” pin in the piston though if using a scrub rod if you're not in position to rebush the rods for a Ford sized wrist pin.  But if going to a custom piston, then by all means optimize the compression height (wrist pin location) to minimize the amount of milling that would need to be performed to the deck surfaces.

Lorena, Texas (South of Waco)

The standard answer here is too use the sbc rod at 6.200" or 6.250" and custom pistons with modified rod bearings. I don't have a clue what shipping/import fees would be too you, but John Mummert in Californa has a real nice stroker kit that takes all the juess work out. I plan on ordering one of his kits using a welded steel truck crank, around $2400 plus shipping here. The kits with cast cranks  start at around $1800.

Glen Henderson



Freedom is not Free

Letohatchee, AL

Hi all, if you offset grind 272/292 big ends to 2" is there a particular  conrod to use or do you stay with the exsisting rods and have pistons made with the right pin and compression height?  what big end bearings are used?            312 crank and rods would be the way to go but I think the would not be to many here in Australia and $ exchange rates and freight from the U.S. for a 312 would probably be more than custom pistons made here.   thanks  Peter  

Pete, one of the Aussie mob. Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390