oil filter housing 90 vs 91+

[DsM KiD4]

is there a size difference in the bolts that hold the 1990 oil filter housing to the block than a 1991+? i just bought everything to complete my air/oil cooled setup, but i think i remember reading somewhere that the oil filter housing bolts are different. is that true or can i use the stock bolts? if they are different, do any of you have the specs on the bolts so i can order them?
thanks in advance

 

[xveganxcowboyx]

I don't know if they are the same. My 90 housing is going on a different block so I haven't compared the two. I had to buy most of mine for the 90 though. Unfortunately the hardware store didn't have the lengths I needed so I just bought longer than I needed and trimmed them down (put a nut on before cutting to realign the threads).

They are M8 1.25 pitch bolts. Off the top of my head I'd say the two longer bolts you need are 70mm and 75mm, but don't quote me on that. I'd just buy an assortment and see what works. Don't forget the washers.

 

[BUCK]

Seems to me like there were some minor length differences on just one or 2 Bolts - You'll want to Torque them up evenly & I used soft loctite - The other thing that comes up is that sometimes one OFH fastener is UNDER the Plastic cover so it's a major PITA unless you just make an access hole for that one Bolt - I ended up just Plumbing up the Air to Oil Cooler to my 91 OFH with NO Oil Temp Valve & never used the 90 OFH - BTW those female pipe plugs in the OFH are LOCTITED in with the HARD Loctite, you MUST hit them with a Propane Torch first to break down the Loctite or you'll be bending up some Allen Wrenches - Good Luck ...