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rebuilding aq170

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kevinmi

Contributing Member
hi guys. i went ahead and started a new thread. Im attempting to rebuild my aging aq170. many of you helped a ton already, but in the interest of documentation for future gluttons for punishment, i wanted to correctly title the new thread.
here is where i am now. I have the engine out of the boat. i took it out at the bell housing. I have since heard that it is not an ideal way to remove it and i should have just left it attached and pulled the whole housing out too (im not sure how to do that, but its ok, cus its already out now). I have it on an engine stand in my garage. tomorrow i will disassemble it and have more questions. one thing i noticed and i mentioned it to my dad. there is a little hole in the housing for the water pump or something connected to the pump on the front of the motor. it totally looks like it is supposed to be there. i was telling my dad that water would come out of that hole when the motor ran, he said they put those holes in car motors to tell you seals were bad. Does this mean that i have a bad seal in my water system? thanks guys! -kevin in michigan
 

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Hi Kevin,

Your Dad was right. If the water pump seals go bad it'll leak water out that hole. That said, if the motor hasn't overheated on you, it's not a problem at this point.
When you get your motor all apart, IF you decide to stay with this particular motor, and if you decide not to get a short block or another motor with low hours-- then find a good machine shop. Take your block, head, crank, pistons, rods, cam, etc.. and have it all done right. Then you'll know if it needs to be bored out, the crank and cam machined, the head done right, etc., etc.. If you just take it apart, do a quick hone job with new rings and bearings--you could end up a motor that won't last long at all. There are books written on how to rebuild motors--it's a big subject. Talk to a trusted auto machinist and maybe a good mechanic who will help you put it all together--the right way.
Hope this helps...
 
I forgot something. Other than the engine being old, why are your doing the rebuild? I was just thinking, it might be ugly on the outside, but if the compression is good in all cylinders, and if the oil pressure was good--and it wasn't making strange noises from inside-- then you might not need a rebuild. If you've done regular maint. then you might be able to get a few more years out of it? Maybe, perhaps? Just sayin'.

Perhaps you could get by with machining the head and a valve job, some new gaskets--exterior parts like a new exhaust manifold, pumps, things like that.
It might help the guys here with many years of experience to give you better guidance if you gave them a little history on the motor. Like how many hours, what it was doing to cause you to pull the motor, etc..
Just wanted to add this to the mix. Doing a complete and proper rebuild is not cheap.
 
im sorry, i continued this thread from "aq170 falls on its face". we did a compression test and all the cylinders are below 100psi. it starts and runs great in idle. it will even go till i hit about 3000 rpms. my plan is to get it apart. see if its just the rings or valves and if everything else looks good, get the head remanufactured, hone the cylinders. put new rings, bearings, gaskets in and get some more use out of it. pistons are not available so if there is more than just the rings or valves to fix, its probably not worth it.
 
Have you priced and/or found an exhaust manifold for the AQ170 engine?

Honestly, I would replace this engine with a GM SBC, and be done with it.


.
 
wow you guys are amazing. a well of knowledge. i just wish u lived around me! thank you kimcrwbr1. thats awesome that you actually found some pistons. the only ones i could find were oversized and 450 euro/each. Rick, are you saying i should just put a different motor in? I would love to get something that has parts more available. i thought that would require a ton of work? i dont think there is anything wrong with my exhaust manifold. at this point, i should at least rip the thing apart and see how bad it is right? if its more than just rings, maybe i should explore a gm motor. i would need the following (just incase it comes to that).: different mounting,different bellhousing,different gear ratio in outdrive, different exhaust manifold (y pipe). am i missing anything?
i found a 1982 bayliner 23ft with a volvo 350 in it, with a 280 outdrive. could probably get it for $1500. that would take care of everything but the mounts? man it just feels like im going in a lot of directions with this. thanks guys as always -kevin on land in michigan.
 
.............................
kevinmi said:
Rick, are you saying i should just put a different motor in?
Not necessarily.... but with the potential exhaust manifold issues, and this being an older push rod engine, and if you love this boat and plan to keep it for a while ????? .... it may be less expensive in the long run.

i thought that would require a ton of work?
The 170 is out now, and must be re-installed.... correct?
This would spare you that time of which could now be spent on the conversion.

You would have some more work to do, and some parts sourcing.
But again.... how well do you like this boat???


i dont think there is anything wrong with my exhaust manifold. at this point, i should at least rip the thing apart and see how bad it is right?
It may be OK.... but if you were to need one, expect difficulty in finding one, and a high price if you do find one.


if its more than just rings, maybe i should explore a gm motor. i would need the following (just incase it comes to that).:
different mounting
Yes.

different bellhousing
that would be a flywheel cover

different gear ratio in outdrive
ideally, yes... but you could run the 1.89:1 for a while

different exhaust manifold (y pipe)
yes... the 3" AQ200B or AQ225B Y-pipe will work with your transom shield.
You would need something like the 3" Barr universal manifold system.

am i missing anything?
crankshaft style seawater pump

i found a 1982 bayliner 23ft with a volvo 350 in it, with a 280 outdrive. could probably get it for $1500. that would take care of everything but the mounts?
I'd buy it only if you can put this boat in the water and test it.

man it just feels like im going in a lot of directions with this.
That's part of being a boat owner.
Click to expand...
 
Rick,

L.O.L. ...Boat ownership either builds patience, decision making and good character--or grinds it down! :)Oh, and then there's the MONEY aspect. :rolleyes::)

"man it just feels like im going in a lot of directions with this.
That's part of being a boat owner."
 
here is a little update: its all ripped apart. i got all the pistons out and rods, crank, pretty much everything. its in the back of the truck and going to take the block,crank,pistons, rods and head to the machine shop tomorrow, along with the manual and he's going to tell me how bad it is. one thing to note, the bearings,and both the tops and bottoms of the rods were all stamped so i didnt need to number them. does that mean its been rebuilt already? the cylinders looked smooth and i could still see the horizontal machining marks on all of the pistons. they all had all of their rings intact. another thing worth noting, there was a dark ring about 1/2" of an inch from the top of the cylinders all the way to the top. it just looked like buildup. not sure if thats a sign of something. maybe ill get lucky and it wont be too bad. as always, thanks again for all of you guys help.
 
new update: i got the news from the machine shop. the head had 2 small cracks in it. he said it would probably be ok because of the location of them and the fact that its a low pressure system. i told him i had an AQ170B (mine is an AQ170C)in my garage that came with the boat. I dont know what the differences are between the 2, but i took the head off and took it to him. he said it appeared to be the same and it had no cracks. he is remanufacturing the head and honing the block ( he said the block was good and no need to bore open). he checked the crank and is just polishing it. I should get it all back tomorrow. I ordered a gasket set for $355 and rings for $55. I have no idea where im going to get bearings. They dont even need to be oversized. He said most of mine were in good shape and all of them would work in a pinch but it would be nice to get new ones since i have it all ripped apart. If i cant find them soon and all the stuff comes in, i guess i will just put it back together with what i have. -kevin still stuck on land, in michigan.
 
No diff in the heads. Make sure you use the thick head gasket and that would be the one from the "C" engine. Back the initial timing down 2 degrees and run it with good gas. I've got some good dual water lines I was going to scrap out if you want them, just pay the shipping.
 
thanks Gary. i was really getting worried that i was doing something wrong w/ mixing the heads. I got the rings in today from summit. I think the gaskets are due in next week some time. I got the block on the stand. it looks sweet all new looking and painted. cant wait to dive in! I dont know about timing and that sort of thing, lol i dont even know what the dual water lines are. if they are the copper pipe, i think i am good as i have 2 sets. Very very nice of you anyways... More info and questions are sure to come. thanks again guys! -kevin (still on land but getting closer to the water) in michigan.
 
i got this one.. its a bit confusing as it has a bunch of different engines but im reading and re-reading a lot lol.
 

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Make sure your lifters go back in against the same lobes on the cam with lots of assy. lube. Valves set at .020 on the intake and .022 on the exhaust no matter what any book says. Head gets retorqued at 5 hours and valves set again.
 
Hi guys. i just about got the thing back together. had a few hiccups along the way. the bearings all checked out at the lower end of the tolerances. i put the old rings in the cylinders and i could fit my thumb in the gap. i think its safe to say they were worn. I also had a piston that a large piece in between the rings was actually broken off and just sitting there. I got lucky it didnt scrape my wall. I just took one out of the other motor and popped it in. i set the valves just the way you said and all that's left really is to put it back in the boat. im hoping for thursday/friday. I was wondering what kind of oil should i use? Also, is there any kind of startup/break in procedure i should follow? thanks as always -kevin in michigan and a special thanks to you rick for answering ur phone :)
 
Hi guys. well after running it in the tub a few times at variable speeds, i finally got a chance to take it out on the water. it seemed to run good. I got up on plane and things were looking good. after a bit, i stopped and looked things over. every thing seemed fine. i set up to troll and got going. I checked things again and discovered my oil looked milky :( i was paying close attention to my oil pressure and my temps and both were very well all a long. I shut it down and used the kicker motor to get me in. I checked the dip stick after things settled down and it was only a little bit over the max line. I had filled it to just under the max line with oil, so not a lot of water was getting in. The engine still runs great. i am hoping its a seal or something like that. what do you think? what would be the next logical step to figuring out where this water is coming from. thanks again for all ur help! -kevin in michigan
 
hmm the oil cooler. i didnt think about that. thats that canister on the side of the engine with all the holes in it right? So i just take it off and take it up to a radiator shop and they would know what to do? sounds a lot better than what i had planned... head gasket, or that gasket behind the the water pump on the front of the engine. Thanks kimcrwbr1 and happy labor day!
 
yeah i took it apart. stupid me didnt look it up in the manual first. man it would be great if thats all it is! ill go take it off right now. thanks! i was more than a little bummed yesterday. on a bright side, we got 2 real nice steelhead before i discovered the milky oil.
 
well i got it apart. i didnt see anything that i would think would be out of the ordinary. regular water came out of the large copper tubes on either end of it. the outside center section was milky but the tube parts wasnt. maybe they wouldnt be because the water pressure is higher than the oil pressure? the filter was milky as was all of the areas where the oil would have been. it appeared that it had all of its o rings and was assembled right. I took the canister off the one that i had in the garage and put it on but i really have no way of telling if that fixes it unless i take the old canister to a radiator shop. i guess ill hunt one up. i checked the dip stick and its only slightly above max but still milky so i am holding off on draining it. It really looks like there wasnt that much water in it. here are some pics. thanks again for your help -kevin
10.jpg11.jpg12.jpg
 
plugs look nice and tan/dry. carbs look much better too. before I had a ton of unspent fuel from the valve cover in them. the drain plug was loose?! we drained the oil and are now cranking it over to get new oil through the engine.
 
well i drained the oil after putting on the other cooler. then added some more. ran it for a few minutes then drained it. looked a little better on the dipstick. then added some more. this time it actually looked alot better, pretty much normal. i ran it for 10 minutes in the tub at varying rpms. still looks good. something tells me there is more to this than what is in front of me. one thing to note. the drain plug was loose and the other day before i took it out, i attempted to wash out the engine compartment out. i left the hose on and pretty much flooded it. it seems a stretch to think that water could get inside through the drain plug but oil would not leak out?
 
found it guys! it was the water pump. the 2 little seals and the o-ring on the shaft that connects it to the to the engine were bad. Got it all back together and ran it at 3500 rpms for a half hr and not a drop of water in the oil! thanks again for all your help
 
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