Crank Girdle/Block Alignment Off

OK-944 · 08-14-2020, 06:07 PM

During my rebuild, I felt a very slight discrepancy between the plane of the front of the block and the crank girdle…over which the oil pump needs to seal. So I pulled the girdle (leaving the crank and pistons installed), cleaned off the Loctite residue, re-glued and re-installed the girdle but this time first tapped the crank and girdle backwards…in hopes of bringing the two front surfaces into a single plane.

Somewhat improved…but the front plane of the girdle is still 0.008” (0.20mm) in front of the block above it.

I then dry-installed the oil pump and ran a feeler gauge wherever I noticed a separation, and could not get anything above 0.20mm to fit. New Hill Garage suggests that while its indeed desirable to have front block and girdle surfaces describing a single plane, its also possible to use the gap tolerance of Loctite 574, which is 0.25mm, as a limit for oil pump installation. In other words, as my gaps are all less than this figure, it should be (according to New Hill) OK for me to go ahead and install the oil pump as is.

Thing is…while I had failed to check this when I took the engine apart…I did notice that the “lay” of the old oil pump sealant looked a bit odd - like the fit between the pump, block, and girdle was not perfect…but the car ran like this for 170K miles without developing a front seal leak.

So…I can either just go ahead and seal and install the oil pump as is, or I could take the girdle back off the block, and maybe bring it to a machinist who might be able to shave off the .008” of “extra” aluminum.

Any opinions?

kdjones2000 · kdjones2000's Garage

Read the shop manual. It talks about this.

OK-944 · 03:36 AM

I don't have the shop manual...what does it say about this?

Also thinking that I could use some shim stock to fill the gap...apply with with 574 above, below, and around this to fill any spaces - should work with a .008" gap. But even though 574 specs mention something about being impervious to oil...I'm not sure if I'd trust this over time - given the oil pressure. Then again, as I'd mentioned, this car went lots of miles like this without leaking.

But again...can anyone share what the shop manual says about this? Thanks!

Edit: Just found a 2010 thread about this...Honda Duster mentions something about the manual's reference to DIY whetstoning to bring girdle and block to level. This is what I'm tempted to try - and am guessing that a coarse (120/240 grit) stone (silicon carbide? diamond?) would do it. Comments?

v2rocket_aka944 · 08-15-2020, 04:30 AM

Easy way to do this is to (dry) bolt the oil pump to the block and girdle first, and then torque the girdle down. The pump's flat surface will align the girdle/block planes.

OK-944 · 12:22 PM

V2 that sounds risky...like it might cause some bit of deformation somewhere, or maybe, given the high torque values for the big nuts on the girdle...create a small crack someplace. Then again, torquing the oil pump as is could deform it perhaps, although with these torque values being much lower I'd think it less of a risk.

I just received a note from someone who'd had a girdle to block displacement of 0.5mm (which is over twice the amount of mine)...and he just sealed it well with 574 and torqued it down...and his car had no issues for the 70K miles he drove it before selling it.

I think I'll to ahead and dry torque the oil pump, with the geared sleeve installed, and also check the amount of angular displacement of the crank, and the crank's concentricity with the seal. Probably push the crank lobes to rotate it a bit, then take things apart and check the gear teeth carefully for signs of inappropriate interference. Maybe I could mark the gear teeth on one side with a black sharpie prior to installing - then check to see how these marks transfer to the mating gear teeth. If I then see anything alarming I'll go ahead and whetstone the front of the girdle, otherwise I'll just re-install everything and call it a day.

Edit: Noticing in a web search that a fair number of folks have this issue...which, assuming that these "factory matched" girdles and blocks have indeed stayed as parts of their original engines - I find a bit surprising.