Chrysler 75 Hp Help With Dissassembly

RCH

Recruit
Joined
Mar 31, 2008
Messages
4
I have a 75hp chrysler 1977
I'm having difficulty separating the crankcase from the cylinder block,
the top comes away but the bottom is still hung up. All visible bolts and dowel pins on the crankcase have been removed. It feels like there are
perhaps some bolts that I'm missing, can anyone help?
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Chrysler 75 Hp Help With Dissassembly

RCH, Huh? You do realize that an RCH is a very small measurement, don't you?

Sometimes the two halves stick together from both the sealant and varnish deposits and sometimes the lower bearing and seal are tight in the crankcase. When you pop the top, the bottom cocks on the bearing and sticks a little. also, if the bottom piston is at or close to bottom dead center, or top, the crankcase half can bind on the crank cheeks. You need to use a little "psychology" on it. Couple of swear words also help--things like, it's making love and it's parents were never married. Only use a lot less words--you know them.
However, before you stick a prybar or large screwdriver in the lower pry point, please double check: There are six 1/4 bolts holding each cylinder flange and there are two additional 1/4 fillister head screws just below the two lower 3/8 x (9/16 head) bearing bolts. These screws seem to have no use but they actually put clamping force on the bottom crankshaft seal if the engine has a separate one, and they tend to be very difficult to remove without an impact screwdriver. Some engines have the seal separate and others have a bearing/seal combo. Factory just never eliminated the screws. Obviously, if you can separate the top, you have removed the alternator carrier/crankshaft seal and the two 1/4 inch bolts that go in the flange from the back because there is no room in the front of the flange

Of course, the two halves are held together at the bearings with one 3/8 stud and nut and one 3/8 bolt at the top. four 3/8 bolts bracket the top and bottom of the center cylinder, and two shorter 3/8 bolts secure the bottom bearing.

If the red spaghetti seal is broken when you remove it, you can substitute small grey screen splining--seals quite nicely, thank you, and seems to be resistant to oil as well. Cheap at the local home store.

When you reassemble, use a bead of RTV silicone--any color--or Locktite anaerobic sealer. I use the RTV when I have some on hand but I prefer the Loctite. Run a small blob at the point where the seals contact the upper and lower bearings. Run a thin bead inside and outside the spaghetti seals and around each 3/8 bearing bolt hole. Not too much or you will squeeze a lot into the crankcases.
 

RCH

Recruit
Joined
Mar 31, 2008
Messages
4
Re: Chrysler 75 Hp Help With Dissassembly

Thanks Frank
Didn't want to snap the crank case half, darn pot metal snap pritty easy.
Will give her another try this weekend.
Thanks again!:)
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Chrysler 75 Hp Help With Dissassembly

Ah---HAH! You didn't tell me the engine was still sitting on the the midleg. Under the match plate there are four studs and nuts; two in the block and two in the front cover. That's what's holding it together. You must remove the engine from the midleg to access these nuts. You will most likely need a rubber mallet to knock off the match plate and exhaust tube. The base gasket will be destroyed and you will need another.

Sorry, computer locked up on the PM so I answered here.
 
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