'73 chrysler 105 surges at WOT then loses power

[Frank Acampora]

Re: '73 chrysler 105 surges at WOT then looses power

Re: '73 chrysler 105 surges at WOT then looses power

Chrysler and later Force used the same rods in engines 20HP and up so yes, you can mix and match rods. If you look, there is a ground tab on the top which the factory used to match weights. Once I did weigh a number of rods and the all came within 7 grams. However, if you do get the stub bolt out, there is no need to replace the rod(s). as long As the threads or the cap breaks are not dicked-up, they will be good. You did match caps to rods and did align them before torquing the bolts, didn't you?

The only caveat though is that early Chrysler rods --before 1970 --had a captive pressed in wrist pin and two needle bearings in the piston. Obviously, you can not use these rods. After 1994, larger late Force engines of all sizes except the 75 had longer rods, larger diameter wrist pins, and the wrist pin hole set higher in the piston so again, they are not usable for your purposes. Stick within 1972 -90 and you will be safe.

At 20 foot pounds, you may or may not have stretched the cap bolts. They are aircraft quality and probably good for 180,000 PSI tensile strength but I am not an engineer and don't have the formula to figure out torque to psi conversion. In your case, as you said, it is better to replace them now. Again, the same bolts were used from (in this case early '60s through at least 1994.)

 

[stubtail]

Re: '73 chrysler 105 surges at WOT then looses power

Re: '73 chrysler 105 surges at WOT then looses power

As an alternative to drilling the remnants of the failed bolt, a competent welder can tack weld, maybe an 8-32 slot-head (or smaller) screw onto the stub that your pliers won't grab. There is no tension remaining on the threeads, and it should turn out by hand. Just a suggestion.

 

[spool]

Re: '73 chrysler 105 surges at WOT then looses power

Re: '73 chrysler 105 surges at WOT then looses power

As an alternative to drilling the remnants of the failed bolt, a competent welder can tack weld, maybe an 8-32 slot-head (or smaller) screw onto the stub that your pliers won't grab. There is no tension remaining on the threeads, and it should turn out by hand. Just a suggestion.

hrmm yeah that's an idea, but then there is a (unlikely) risk of welding to the rod and unbalancing it or warping the rod. i think a easy out is a safer and easier option.

I think even the process of drilling it may even turn out the thread as i cleaned and lubed the thread before installing to get a true torque reading.

 

[3rdtimesthecharm]

Re: '73 chrysler 105 surges at WOT then looses power

Re: '73 chrysler 105 surges at WOT then looses power

Try a left-hand drill bit.I`ve got bolts to back out while drilling in reverse.

 

[spool]

Re: '73 chrysler 105 surges at WOT then looses power

Re: '73 chrysler 105 surges at WOT then looses power

I'll give it a shot, ive been told a pin punch on the edge should work too, i can get at the top of the screw easy, migh be worth thile drilling it from the top with a normal drillbit.

I found some bolts locally. $11 each but i'll have them come monday.

 

[Frank Acampora]

Re: '73 chrysler 105 surges at WOT then loses power

" I cleaned and lubed the threads to give a true torque reading." Are you aware that most torque values are given for dry assembly? Lubrication of threads can DECREASE the torque needed for the same clamping force by anywhere from 5 to 20 percent.

Don't worry though. The con-rod threads almost always have some oil in them and it hasn't snapped a bolt on me yet torqueing to 180 inch pounds. (I know, your manual says 170--potato, potahto. Not that much difference and I am almost certain that factory manual on my 125 calls for 180.) I don't have it handy to check though.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

" I cleaned and lubed the threads to give a true torque reading." Are you aware that most torque values are given for dry assembly? Lubrication of threads can DECREASE the torque needed for the same clamping force by anywhere from 5 to 20 percent.

Don't worry though. The con-rod threads almost always have some oil in them and it hasn't snapped a bolt on me yet torqueing to 180 inch pounds. (I know, your manual says 170--potato, potahto. Not that much difference and I am almost certain that factory manual on my 125 calls for 180.) I don't have it handy to check though.

Ok, paid a thread specialist to come extract it for me, he did a pro job
my new merc bolts arrived and they're the right ones.

Time for assembly.... again using the correct torque setting.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

Ok, Engines assembled using 180inch pounds on the conrod bolts, (dry) it felt much better torqing up.

I'm nearly ready to install the motor,

Frank i've got a question for you, I can't tell from the manual but the top crankshaft seal is that installed normally or reversed like the bottom crank seal?

 

[Frank Acampora]

Re: '73 chrysler 105 surges at WOT then loses power



The top seal is installed with the open end or spring end down. The flat side of the seal should be just about even with the surface of the stator mount. Dry fit the mount and look closely before installing the seal. You will see that if pressed too far in, it (the seal) will contact the land on the crank and if not far enough, only one lip will contact the seal area. The O ring should seal the stator mount to the block, but a little silicone RTV on the surface of the mount can not hurt. One bolt is offset and the belt opening faces the distributor so the mount only installs one way.

This one happens to be an adapter to convert Magna-Power II to distributor ignition and does not have an O-ring, but the seal area is the same. Give me a second. The forum is not letting me manage attachments.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

Thanks Frank,

My plate is square and had RTV sealing it to the block, I'll put it together tonight. I should have it installed and running by mid week.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

well good news, I got it started. (only ran it for a few seconds)

140psi on all 4, i just need to break it in.

 

[chrome dome]

Re: '73 chrysler 105 surges at WOT then loses power

bewdynewc!
goodonyamate!

now, can l trouble ya for where you got the parts/bolts locally from?
contemplating re-building one myself..bit smaller though,
cheers

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

It was fun sourcing the parts, most of the parts i got the code for and went through a local dealer (as half the parts are sold as Mercury parts)

the rest from Crowley marine or ebay.

I've got a second set of conrod bolts coming if you want them for cheap? as i ordered them from the states then decided i didnt want to wait 5 weeks and bought them locally.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

Trying to track down part #F85965 (Engine mounts)

mine have seen better days. Apparently its a obsolete part, Does this mean no one makes them anymore and ill have to find 2nd hand parts?

 

[Frank Acampora]

Re: '73 chrysler 105 surges at WOT then loses power

In all the Chrysler and Force larger engines I have had, worked on, or still have, I have never seen a bad set of upper shock mounts. SO unless yours have actually failed and the metal has separated from the rubber, they should still be reusable. With age, because the leg casting is tapered, the rubber will take a set and be thicker on one side than on the other.

The same part (top, circular biscuits) was used on all larger engines all the way up to

1993 so you can get them from almost any junker 85-150 HP engine. Some (like yours) used a 3/8 bolt in both the top and bottom holes while some later ones used a 1/2 inch bolt in the bottom hole. If you got a set of these, all you need to do is drill the front plate to clear that size bolt. The lower mount (top three photos) was changed around 1978 to a smaller slotted plate when Chrysler went to the one piece lower unit. So, if you need one of those, you are limited to earlier engines. However, even if the rubber has failed, as long as the aluminum is sound, this unit can be repaired and made better than original. Use a good industrial rubber adhesive and a couple of screws 5/16 diameter or equivalent.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

View attachment 126229View attachment 126230View attachment 126231In all the Chrysler and Force larger engines I have had, worked on, or still have, I have never seen a bad set of upper shock mounts. SO unless yours have actually failed and the metal has separated from the rubber, they should still be reusable. With age, because the leg casting is tapered, the rubber will take a set and be thicker on one side than on the other.

The same part (top, circular biscuits) was used on all larger engines all the way up to
View attachment 126228
1993 so you can get them from almost any junker 85-150 HP engine. Some (like yours) used a 3/8 bolt in both the top and bottom holes while some later ones used a 1/2 inch bolt in the bottom hole. If you got a set of these, all you need to do is drill the front plate to clear that size bolt. The lower mount (top three photos) was changed around 1978 to a smaller slotted plate when Chrysler went to the one piece lower unit. So, if you need one of those, you are limited to earlier engines. However, even if the rubber has failed, as long as the aluminum is sound, this unit can be repaired and made better than original. Use a good industrial rubber adhesive and a couple of screws 5/16 diameter or equivalent.

one of the metal plates is cracked on one mount and the other seperated they are both failed.

I may aswell buy some second handers i guess!

Thanks for the info

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

View attachment 126229View attachment 126230View attachment 126231In all the Chrysler and Force larger engines I have had, worked on, or still have, I have never seen a bad set of upper shock mounts. SO unless yours have actually failed and the metal has separated from the rubber, they should still be reusable. With age, because the leg casting is tapered, the rubber will take a set and be thicker on one side than on the other.

The same part (top, circular biscuits) was used on all larger engines all the way up to
View attachment 126228
1993 so you can get them from almost any junker 85-150 HP engine. Some (like yours) used a 3/8 bolt in both the top and bottom holes while some later ones used a 1/2 inch bolt in the bottom hole. If you got a set of these, all you need to do is drill the front plate to clear that size bolt. The lower mount (top three photos) was changed around 1978 to a smaller slotted plate when Chrysler went to the one piece lower unit. So, if you need one of those, you are limited to earlier engines. However, even if the rubber has failed, as long as the aluminum is sound, this unit can be repaired and made better than original. Use a good industrial rubber adhesive and a couple of screws 5/16 diameter or equivalent.

one of the metal plates is cracked on one mount and the other seperated they are both failed.

I may aswell buy some second handers i guess!

Thanks for the info

 

[Frank Acampora]

Re: '73 chrysler 105 surges at WOT then loses power

Sorry to tell you this, but you need to remove the block in order to replace them. They are set into a square recess in the midleg flange and the top bolts are under the block. Bummer! However, while you have the block off, replace the two thin washers on each side with thick stainless "Fender washers" and replace the bolts with stainless. That is, If you intend to keep the engine. If you do replace the washers, be certain that they do not sit above the level of the recess as this will keep the block from setting down onto the midleg.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

Sorry to tell you this, but you need to remove the block in order to replace them. They are set into a square recess in the midleg flange and the top bolts are under the block. Bummer! However, while you have the block off, replace the two thin washers on each side with thick stainless "Fender washers" and replace the bolts with stainless. That is, If you intend to keep the engine. If you do replace the washers, be certain that they do not sit above the level of the recess as this will keep the block from setting down onto the midleg.

Yeah i know, Just the midleg needs to come off which i can do using a engine crane to support the motor.

 

[spool]

Re: '73 chrysler 105 surges at WOT then loses power

It's all fixed and running well now heading off to the water tomorrow