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Aq131d cylinder head question

Ok, so the dilema continued...After resetting the timing gears to the marks AGAIN...I came to the conclusion that if the pulley will not line up at 0 but the crank gear is, then I should be looking to adust it to 16 degrees using the 10 degree mark as 0. So everything lined up, belt on, placed the distributor back in the engine and aligned. Started right up, I let it warm up to about 180, then adjusted the dist to get the idle down to around 900-1000, checked the adavance, it moved as it should. I then rotated the dist to get it to about 6-10 degrees, ran rough, so I moved it back to 16, smoothed out and no backfire, still runs a little rough and then it smooths out, then rough and then smooth, however, it is not idling up and down. turned the screw to lightly seated and the backed it out 2 turns, did the same with the idle screw. At least its running. Now just need some advice on getting it smoothed out and whether what I did makes any sense.
 
Wonder if there is a difference in the volvo auto pulley and the volvo penta one. Ha...did you catch the price 2,166.00...tell me that ain't ridiculous.
 
Yes, the difference in price is ridiculous, but most of the VP parts prices are nothing but armed robbery IMO. Luckily, there are alternatives with the OHC 4 cylindre engines. :D

Maybe the difference between the marine and automotive vibration dampers would be the location of the timing mark and you had an automotive pulley installed on your engine for starters? I don't know of many people who would spend over $2,000 on a vibration damper.

If the engine starts and runs smooth at least at first, I would forget about the location of the pulley mark for now and keep those 10º difference in mind when seeting the timing. The important thing is that you get the advance set at 32º-36º BTDC at 4200 RPM. Then, to smoothen the idle you will have to play with the idle mixture and idle speed until you find the sweet point.

If the timing does not advance with the speed from 6º at idle to 32º-36º at 4200 RPM and then returns back to 6º when going back to idle, you may have to check the condition of the distributor advance weights and springs.

I think you are getting very close to get the engine running the way it should. Then, time for sea trials.
 
Couple of new questions. First, i think the timing is ok, bought a used volvo penta pulley yesterday, will see how different. Ok, after running the boat, the temp came to about 170. No issue, rpms seem fine, going to try to upload a video with sound for which hopefully will be good enough to hear what hear. So there is a vibration in the engine which shakes the sterndrive, then goes away, this happens every few seconds and last a few the smooths out. Second thing, after shutting down, I opened up the oil dipstick on the drive to see the condition of the oil in the stern, it shot out of the top like it was compressed, good news was that it was not milky white, just blackish green. Is it normal for the oil to come out like that? Was it because it was running prior to opening up the screw? Haven't had it in the water yet, but at least it starts. Just want to get these few items nailed down, I think I still have some air to the carb issue to resolve. How noticable will it be turning the air mixture screw?
 
That would be cool. I also did some shopping and picked up a used damper hoping that it is an original part to the bayliner it came from and wasn't replaced with an automotive one. Bought it to do the same, check the timing marks. The auto one I bought new lined up the same as mine. Although I should have expected it because mine is also from an auto. I broke the original one a few years ago trying to remove it. Thanks again, at least it runs, just gotta make some adjust and then hopefully get it on the water. http://my.ebay.com/ws/eBayISAPI.dll?MyEbayBeta&MyEbay=&gbh=1&guest=1
 
Timing gears form a car are exactly the same as automotive with the added advantage that they are not pitted by salt water. I would always recommend getting the timing gears from an auto wrecker or from an auto parts store.
 
Duh! What the hell was I thinking of? I will reword my previous message since I am unable to edit it. :mad:

Timing gears form a car engine are exactly the same as their "marine" counterparts with the added advantage that they are not pitted by salt water. I would always recommend getting the timing gears from an auto wrecker or from an auto parts store.
 
I agree. Although I wonder why my damper pulley does not line up as everyone indicates it should. I know that the gear behind the pulley is lined up at 0 so maybe the pulley does indicate 10 degrees and that would be why when the ignition timing is being set you retard the dist to get 6 degrees with the timing light? I might not be as dumb as I thought!:cool:
 
good thing is it has life. Can you point out what might cause the vibration in the engine on and off? I know it shakes the drive then smooths out, then goes and does it again.
 
rdengil1 said:
I agree. Although I wonder why my damper pulley does not line up as everyone indicates it should. I know that the gear behind the pulley is lined up at 0 so maybe the pulley does indicate 10 degrees and that would be why when the ignition timing is being set you retard the dist to get 6 degrees with the timing light? I might not be as dumb as I thought!:cool:
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I hope you are just kidding. I don't know everything, but in my books a TDC mark is a TDC mark. And 6ºBTDC is 6º Before Top Dead Center. And as far as I can recall I have never participated in a discussion in this forum (and I have participated in a few) about the timing marks being off 10º on any OHC AQ 4 cylinder engine. Have I missed something during all these years? :confused:
 
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rdengil1 said:
good thing is it has life. Can you point out what might cause the vibration in the engine on and off? I know it shakes the drive then smooths out, then goes and does it again.
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Check again when the boat is in the water. If the vibration is still there, then it will be time to think about its origin.
 
kimcrwbr1 said:
Thats what I say with the lines and marks all lined up correct set the timing at 16 dbtdc should be 6 degrees with the volvo penta damper pully. Adjust the idle air out as far as necessary for a smooth idle at 900 rpm. Once again set the idle air out for max rpm and adjust the idle speed with the stop screw. Make that adjustment with the control cable off so it dont interfere with the travel of the butterfly, Then adjust the throttle cable so the spring has slight pressure on the throttle lever pushing it closed to the stop. Get it on the water you have put it off long enough. I suppose you could just put a mark on the damper pully when you have the marks all lined up put the damper on and mark it at TDC and use that make for timing purposes. Check the total advance also take it to 4200 rpm the timing should be between 32 and 36 DBTDC. If it runs good go kill some fish.
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Now, that sounds like a plan.

Not sure if I misunderstood the first post of this page, but this is far clearer. I cannot figure out why the pulley is 10º off, but if you are 100% sure that the timing belt is installed correctly, just do the timing compensating for those 10º. You will find out during sea trials if there is something wrong with the timing or not.

Good luck, Spring starts tomorrow and it's time to get your boat ready. :)
 
I dont think I can be wrong everytime with regards to setting the timing gears to TDC, had to have gotten them at least once;)! Probably this time. especially happy coming home from work and just turning the key starts it. and its quiet except for the vibration. the v belt is in the correct groove and lined up appropriately with the water pump and alternator. What exactly do you mean with the air screw adjust out for max rpm? May try taking it out next weekend, buddy going out with his incase I need a tow...
 
Well pulley from ebay arrived, guess what?? It is 10 degrees off to the good. I put it on and lined up timing marks on gears, put the pulley on and bam! it lined up under 0. So for anyone who wants to know, apparently there is a difference between the automotive pulley timing mark and the volvo penta marine crank pulley. So happy. The auto has one large dot, the marine 3 (dimple type).
 
Well, that explains a few things. However, do you see any other significant physical differences between the pulleys (weight, size, shape, etc) other than the timing mark? If not, remarking the automotive damper would always be a solution. As long as the automotive v-pulley is aligned with the coolant pump and the alternator, there should be no problem.

I said before that experience is the art of learning from screw-ups. Today, many of us have become a little bit more experienced. ;)
 
The automotive pulley has only one large dimple, the marine one I got today and one I saw online have three large dimples. At least I know I was not crazy and after all the posts I made, I had always been lined up correctly. Funny. Learned something new today.
 
Well, now that you have sorted the pulley problem, now get that ignition timing set, as well as the idle mixture and idle speed, then recheck/readjust again with the boat in the water and get some sea trials done. I'm looking forward to see the results.
 
raining here at the beach, also have to work, will probably take it out next weekend. Gives me a chance to fine tune and then get someone with another boat to go out as well...just in case. Trust me, I'm ready to get out there and hopefully have a successful trip.
 
Last time I posted was the end of March, here it is the end of July and I finally gave the boat some love. Splashed it yesterday for the first time in more than 2 years. It appears the rebuild and all the headaches paid off, boat started right up, idled smooth at about 900-1000 rpm, very quiet. Backed off the pier and headed to the channel, the no-wake zone is long, so the engine had plenty of time to warm up. Ran about 4.5knts in the no-wake zone, small water leak from the expansion tank where the coolant cap is, had to tighten down, leak stopped. Water temp about 180. throttled slowly up and it seems to want to stall, not sure why, but no backfire, just tried to stall. So I backed off the throttle to neutral, the engine kept running. throttled up quickly and the boat took off and got up on plane quickly. ran it at 4000-4300 rpms up the channel and into the bay. No leaks or issues that I could tell, except the water temp, it rose to about 195-200 and remained there at full throttle, once I slowed it down, it dropped to about 180-185. Not sure if this is normal, since I don't remember what the temp used to be. I do know that on the muffs in the driveway, not under load obviously, the temp was about 160. So here are my concerns:

Is the 190-200 temp normal operating temp?

what needs to be adjusted to keep it from stalling when I push the throttle forward slowly? I also noticed that I could pump it forward, kind of a jerking forward and back quickly to keep it running.

Gas guage continuously pegs from full to empty and back, like it gets a burst of electricity, then cuts out, then gets another, etc. I filled it with 10 gallons of fresh gas prior to dropping it in the water and it registered about 1/2 tank. then started flickering about.

Other than these three items, the boat seems to be running awesome, it was nice to get out and test it. Now I look forward to getting these issues solved and then heading out for some late summer flounder fishing and the on to the reds, taug, and striper. Thanks again, Dennis
 
Did not replace the thermostat. The leaking actually was from the coolant cap not being seated and tight, that stopped. The v-belt is tight, the temp gauge is correct. I did not confirm the 6 degrees at idle and the advance under load. I did this on muffs in the driveway and it was correct. Will bring the light with me when I get back out. The gas guage does not hold steady, just jerks back and forth. The carb is brand new, I believe it may be the air adjustment and the carb is the old style large screw (2 turns I believe.) Other than that, she ran nice. I read that the water temp for this engine is at 190. I changed the cylinder head to the automotive head and swapped the cam. The head I used is the 530 vice 531. My understanding is that the 531 has better flow than the 530, so I wonder if this also could be why my temp is a little higher.
 
I have to disagree with kimcrwbr1 on this one. The operating temperature for your engine is between 180ºF (thermostat starts opening) and 198ºF (thermostat is fully open). This is the cooling temperature range specified for all the VP OHC 4 bangers.
 
I thought it would be ok since it didn't get any hotter at full throttle running for about 10 minutes. It never passed 200. Was fun, just need to get the rest of the bugs out with the carb adjustment and the fuel gauge pegging.
 
Interesting and informative thread. I have twin AQ151s and here is my 2 cents worth. It sounds to me like you're running too hot. I don't like it when mine exceed 190 degrees. I've found that if i have too much antifreeze mixed with water it runs hot. Might try draining some and diluting it.

Also, I have the newer style carbs with the main jet and idle mixture screws facing away from the head rather than toward it. Mine has dual carbs being a 151. May not make any difference other than easier to adjust.

Glad you're back on the water.

Did you ever decide if the automotive Harmonic balancer is different than the marine?

Jim
 
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