202 red in boat tricky issues??

[Marksboat]

Hi all. Firstly I gotta say I'm so glad I stumbled on this forum. So g'day to you all. I'm a long time Holden owner having owned just about every model they ever built from my first car a fb wagon to our family vz wagon.
But my question today relates to my inboard boat with a 202 onboard.
I don't know the history of he motor but it seems VERY NICE. Someone has either started with a nice stock motor or had it reconned.
I shoulda mentioned I'm not much of a mechanic but know probably just enough to get myself into trouble, and not quite enough to find my way out again!
To the boat....I have a REAL LOUD pinging or rattling under load at higher rpms. I call it pinging as that's the best description I can think of but it's way harsher than what you'd expect from low oct fuel or timing issues. And before anyone offers the suggestion of timing, here's what also happens. I can floor the boat and she goes great but after a short (10 seconds?) time the rattle develops, gets worse and I have to throttle back for fear of something breaking. If I bring it down to an idle, it develops a lumpy 'cammy' loping idle and will often stall. After I restart it, it usually runs fine until I give it some stick. Sometimes even after being switched off for a while it won't run smooth and I've got to squirt the throttle a few times to get her up and going. Under light to 3/4 throttle she runs all day and is as smooth as silk, no rattles, blowby, just as sweet as!
I have recently replaced the points dizzy with a Bosch hei from a later motor, made sure I have full 12 v at coil which was also the hei transformer style and I used all new leads and regapped the plugs tp 1.5
mm and set the timing by ear. It starts instantly and idles perfectly and has instant throttle response.
I didn't notice this issue prior to changing the dizzy but I only used the boat once and never really floored it. On the first day out the old oil filled coil died and we had a bit of a paddle into shore! I figured this was because the old coil was receiving continuous 12 v and cooked. So I replaced it all with the hei.
I thought it could have been fuel starvation under load but the lopey idle has me stumped. I have made sure the tank has a good breather and the glass fuel bowl on the stock fuel pump always looks full even when misbehaving.
I can't tell you what the revs are as the tachometer isn't working. But I'm not thrashing it, I'd guess it's around 4,000 revs. There's still lots more left in her before she starts to ping.
Could this all be due to the lifters pumping up? I've read up all I can on this but nothing seems to sound just like my problem?
A friend who is a very experienced mechanic suggested some 26 thou spacers under the rocker saddles as a try. I just don't know enough about all this and don't want to start playing around with things I'm not too familiar with. The pcv and oil breather system all seems fine. As I said, this motor has NO rattles or noises until this point, has exc oil pressure that is pretty low at idle, and seems to be a very quiet motor!
I've read about anti pump up lifters but seem to get mixed opinions as to how well they work. If anyone else feels this is a valve train issue, would I expect any improvements from fitting new springs, and should these be standard springs, and would new standard lifters be worth a try? How much difference would oil and or oil filter make? I haven't changed either as I was told by the previous owner it'd just been done and certainly the oil looks relatively clean.
As you will understand, the motor runs cool as it's pumping cold water straight from the sea and has no thermostat so maybe the oil is cooler than in a car engine? Cooler oil = thicker oil?
I've tried to explain things in as much detail as I can so as to avoid too many questions establishing what I have and haven't done.
So sorry for the long post. But if anyone can help me shed some light on this, then I'd REALLY appreciate it.
Thanks. Mark
Ps - I should have mentioned that she loses power once the pinging starts?.

 

[greenacc]

Gee that is a long post. The first problem with putting a car engine in a boat is that it's not designed to be in a boat, obviously.
There could be issues related to the prop, ie the torque curve of the motor does not suit the pitch of the prop nor weigth of boat or speed, etc!
Other than boat issues, FIX the dam tacho! You are only guessing if you dont have a working tacho on the boat. Out boards rev much higher than the old red motor so revs and prop selection is critical. Red motors are pretty simple, if you have enough fuel, air and coolant flowing they should run all day. Maybe fit a fuel pressure gauge also ? Failing that get someone to feel the fuel hose while the issue is present to see if you have enough fuel pressure at high revs. The cam in the engine may not be designed for high revs either. 1.5mm sounds like a big gap fora red motor? Is that the right gap? Its been 15 years since i owned one but i thought the gap was 1.1
Are you running 98 fuel in it ? Has it been 'converted to unleaded fuel ? Is the exhaust set up properly to give suitable 'backpressure?'
Goodluck, red motors are awesome !
Edit, put a ####ing thermostat in it ! You cant floor an engine thats running cold water ,,,,,,,,,,!!!!!!!

 

[VR38]

No problem before you replaced the dizzy/coil???
Now it will only run clean at 4000rpm (your approx guess)
I would be having a real good hard look at the dizzy.

 

[Jonah 101]

dont tune a dizzy by ear lol Sounds like you have way too much advance.

 

[Marksboat]

Thanks guys. Greenacc, your point you make about cold water interests me? Car engines have been running in marine situations for years......have a look at all the ski boats around with Holden and chev v8's.
But you're right, they're not designed for this and there will be compromises. The manufacturer of this boat hull is well recognized and would have fitted hundreds up with this combo, my bro had the same set up with a 186 and that was awesome. And yes, I'm a actually waiting on a new tach to arrive then I'll know the revs. 1.5mm is the correct gap for hei, as I've been informed. And the boat goes exceptionally well, has heaps of go, exc power no ping g under load ......but it develops after a bit? Surely having too much advance would be evident immediately under load? And then why the rough idle?
VR 38 and Jonah, thanks guys, and first thoughts would be timing, but this is actually the second elec dizzy I have fitted as the first had a knackered vac advance diaphragm so I replaced the whole lot. Same problem. And as I mentioned, didn't notice it with points ign but didn't push the boat hard on that one and only outing before the old coil cooked. I have also tried adjusting the timing on the water with no success. So I'm pretty sure it's not timing....
I might try a fuel pressure gauge as greenacc suggests. Any one know what I should be looking for pressure wise?
I'm still leaning towards lifter issues, does anyone have experience with similar noises due to lifter pump up?
Thanks again all.

 

[Brett_jjj]

If I run 91 octane unleaded fuel in my HQ 202 ute, it pings badly and rattles its guts out whenever its put under any sort of load, (it sort of sounds like a tin can full of marbles being shaken).. If I run 98 octane fuel though, it runs excellent and doesnt ping/rattle at all except for when its under full throttle, where it will still ping very slightly.. These old engines were designed to run on 96/98 octane super fuels, so running them on 91 octane fuels is not good for them and will eventually kill the engine. You can back off the ignition timing from the recommended setting of 6 degrees BTDC, to say 8 - 10 degrees BTDC, but this then causes a fairly large power loss and makes the vehicle use way more fuel than it normally would. Try some 98 octane fuel mixed with a bottle of octane booster, then see if it still does it.

 

[Marksboat]

That's worth a try. It's an excuse to put her in the water and wate some fuel. But I suspect something else is happening otherwise it wouldn't run great then deteriorate. Still hoping to hear from anyone with experience on these motors regards the possibility of lifter pump up or weak springs and whether this could cause pinging or if I may be hearing valve bounce.
Thanks Brett

 

[greenacc]

Hey Mark, reason i'm amazed you run it on cold salt water is that the engine is designed to run at a specific operating temp. This is the purpose of the thermostat, to open and close to control flow of cooling water to maintain correct operating temp of the engine. This ensures you get maximum power, fuel economy, correct oil viscosity, max engine life and so on. Running it on cold water could have negative effect on all those things. The only possible advantage i can think of for you is that in a car you don't usually sit on 4grand all day. If you do you would eventually overheat the engine, so MAYBE just maybe running cold water gives it increased cooling effect for sustained high speeds but it still sounds dodgy to me. The other thing that is possibly missing here is pressure ie radiators are usually a closed system so the coolant is pumped around at a set pressure. What kind of pressure does your coolant flow at ?
I don't think it has been mentioned yet what carby you are running, is it a standard torana style carby ?
When you floor it and it goes good, then starts pinging, it you slow down for say 20 seconds then floor it again will it go good again ? This would suggest fuel system to me as that slow period woulf give fuel pump a chance to refill the carby for another spurt....