Chrysler 105 - standard rings for 0.010" over?

[stubtail]

Tore down the powerhead on the old girl (#1 only 30 psi) and she is not in good shape (really need a new block), but hoping to clean her up, quick hone and toss in new rings, cowl her up and give her a chance. The bores measure 3.321" give or take (standard 3.3125") and the OD of the pistons is 3.315". Looking at online catalogs, there are no rings listed for .010" over. Am I to assume standard rings are what I will have to install?

If anyone has experience with this problem, any advice would be appreciated.

 

[Frank Acampora]

Re: Chrysler 105 - standard rings for 0.010" over?

A quick hone is just not going to do it. You really need to bore it over and install oversized pistons.

Cylinder tolerance for out of round, barrel shaped or wear is only .002. And, you are well out of tolerance. measure the pistons at two points 90 degrees apart. They are cam ground and have a major and minor diameter.

It is not just a question of the rings and upper cylinder compression, but also of the piston skirt clearance in the bore. Pistons do double duty pumping in the fresh charge on each upstroke and compressing it on the down. Too large a skirt clearance and the pumping efficiency goes way down and you lose horsepower.

By trying to install rings only, you are not doing it slow, not doing it fast, but doing it half fast! LOL

If you insist on rings only, try franzmarine@aol.com or contact Franz at the Chrysler crew.

 

[stubtail]

Re: Chrysler 105 - standard rings for 0.010" over?

Thank you Frank for your interest. I should have divulged a little more about my tale of woe. The #1 was down @ 30 due to a blown head gasket. #2 was @ 85 with scored and sticking rings while #3 & 4 were reasonable @ 140 and 145 respectively. During the teardown, I recovered plenty of shards of grenaded impeller throughout the cooling jacket (current impeller was OK), and I can only assume this thing had been cooked. (I purchsed the old engine on a newer boat knowing there was "something wrong" with the engine, but I didn't mortgage the ranch to obtain the package) As it stands, I cannot reasonably go the proper route of a rebore, new pistons, etc. as the #1 & 4 sleeves have cracks running between exhaust port holes and the #2 sleeve has a 1.5" crack running from an exhaust port toward the cylinded base. The aluminum casting is also cracked, but it does not appear to breach the cooling jacket - at least not yet! I don't think I have enough remaining to properly rebuild this engine, at least keeping within my limited budget.

 

[Frank Acampora]

Re: Chrysler 105 - standard rings for 0.010" over?

Judging from your description, there is really no hope for that block. Mounting another good block on the leg would be the best way to go.