1977 chrysler 105hp motor

[corney]

i have already posted a message on this topic and lutenant commander was good enough to respond. i am posting this on behalf of friend and it seems i may have conveyed the message incorrectly so i will try again:<br />number 4 piston is damaged and has a large scuff down the side with a small hole in it. the crown is blown away in a crescent shape, rings and all at about 10-11 o'clock adjacent to exhaust port. <br />a friend had a 85hp 3 cyl motor identical had damage to number 3 cyl. why? thankyou

 

[rodbolt]

Re: 1977 chrysler 105hp motor

the 3 things that eat crowns are usually caused by a lean fuel mix due to a clogged carb. over advanced ign timing or overheat.on the old distributor motors over advanced timing will normmaly show marks on all cyl. the most common causes are overheat and lack of fuel in that cyl.

 

[Frontier1]

Re: 1977 chrysler 105hp motor

Hi Corney and all iboaters, I've just joined iboats as it seems that this site has an excellent knowledge base within it's members.<br />Anyway, I have just bought myself a secondhand Chrysler 105hp (either '74 or '79), like yours.<br />With mine, I have been told by the previous owner that one of the piston gudgions is broken, however it has been sitting in his carport for the last 5 years with the headplate(?) off.<br />I would like to know how you are going with yours as it may help me out with what I need to do with mine.<br />BTW, do you know whether it should be possible for me to turn the flywheel by hand to check piston movement or can I only do this by using the starter?<br />TIA, Frontier1

 

[Frontier1]

Re: 1977 chrysler 105hp motor

I of'course mean't '77 or '74.

 

[WillyBWright]

Re: 1977 chrysler 105hp motor

You should be able to move the flywheel by hand, especially with the cylinder head off. I assume the Headplate is the cylinder head.<br /><br />Gudgeon:<br />4. (Mach.) The pin of iron fastened in the end of a wooden shaft or axle, on which it turns; formerly, any journal, or pivot, or bearing, as the pintle and eye of a hinge, but esp. the end journal of a horizontal. [1913 Webster]<br /><br />6. (Naut.) A metal eye or socket attached to the sternpost to receive the pintle of the rudder. [1913 Webster]<br /><br />I have to assume you're talking about a broken connecting rod. Consider your motor as a Parts motor and look around for more. You might find enough to be able to assemble one running motor out of components. That powerhead probably isn't woth overhauling.

 

[Frontier1]

Re: 1977 chrysler 105hp motor

Hi WillyBWright, <br />Yeah the cylinder head is off but as this has exposed the pistons and bores to the elements (not rain) for the last five years, I expect there would be some stiffness in getting the flywheel to turn. This may however be more to do with the "Piston Pin" or as we also call them down here, the gudgeon pin being broken apparently.<br /><br />I have already spoken to my local mech' engineers who are happy to re-bore the barrels for only a small sum as I do alot of work through them.<br /><br />My concern however, is that I will probably have to pull it entirely down simply because of the amount of time it has been sitting in this guys carport.<br /><br />Getting back to the turning over of the engine, if it is simply the piston pin, should I try and connect a battery and try an actual electric start just to see if that will "unlock" the engine? (so to speak)<br /><br />TIA, Frontier!

 

[novicetech]

Re: 1977 chrysler 105hp motor

I woud advise against using the starter to try to turn the motor over. You could do m ore damage to the cylinder sleeves. Have you tried to turn over by hand? I would think it would move a little bit in one direction or the other, as long as the sleeves dont look rusted. If they do look rusted you might try some penetrating oil.

 

[Frontier1]

Re: 1977 chrysler 105hp motor

Hi Novicetech, Trying to see another option here. I have sprayed in quite alot of lubricant and all pistons can be moved slightly side to side except top piston.<br /><br />You point out a very real risk with an electric start but I cannot turn that flywheel and was thinking that even a one or two second "touch" of power to the bendix (starter motor) could be enough to loosen that one piston which might be holding the others back.<br /><br />If however you feel that that still might be too risky I still have to pull the powerhead off anyway. I just thought it might make my job a little easier by loosening that stuck one.

 

[Frontier1]

Re: 1977 chrysler 105hp motor

G'day again,<br />Thanx WillyB for the tip on kero in the barrels. After a few hours I did start to rock the flywheel back and forth with a suitable socket and not long after about 20 minutes, the pistons finally freed up!! Great tip!<br /><br />Next is loosening all the bolts so that I can slide off the block and see what condition the rings and rods are in. Hopefully none of the block bolts will snap, fingers crossed.<br />Cheers, Frontier1