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Need help setting up a AQ211A after partial rebuild

S

shaunleveque

New member
Hi from a Newbie.

Sorry my first posting is a question and I haven't introduced myself previously.

I have been searching for help with a problem I have with an AQ211A V8 Petrol engine and came across this site and lots of helpful information. But, I think I might have more problems than I first suspected.

I recently partially re-built an AQ211A engine fitted to my Fairline Sprint. I managed to get the boat really cheap because of the damaged engine.

The damage was limited to the *even* cylinders side of the engine. An exhaust valve had jammed slightly open and the previous owner had continued to run the engine for a while. Fortunately, this didn't seem to cause any other damage to the engine. It was inspected by a marine engine engineer.

I had the head skimmed, changed the valve, seat and guide, and had all the other valves checked and re-ground.

I re-assembled the engine and re-fitted the distributor and all seems to run well with no load, and the timing seems to be OK (as long as I'm using the correct timing marks on the engine....Not sure about that.........more on this shortly).

I found the diagram (below) in another thread (kindly posted by RicardoMarine), so I've copied and pasted it into this thread for ease of reference (I hope they won't mind).

What intrigued me about this diagram is that I find my No:1 *seems* to be where the No:8 is on the drawing.

Maybe I've messed up big-time??

I cannot get any more than about 10 - 11 knotts out of my boat at the moment, and under load it will never rev to higher than 3000RPM.

Also, (and I don't know if it's relevant), the exhaust riser on the "even" side always seems to be much much hotter than the "odd" side after the engine has been run for a while.

Do you think I've got my distributor all wrong?

As for the timing marks. The marks on the pulley are clearly marked. But, there is a "saw-tooth" plate on the block that I assumed was the corresponding marks, and I assumed the larger triangular cut-out "tooth" is the one I should be aligning my marks with. I am aligning the appropriate timing marks with the deepest part of the largest "V" in the plate.

I have a good stroboscopic light with inductive pick-up, and the marks seem quite stable at the quoted revs. (6 Deg BTDC @ 750rpm and 14 Deg BTDC @ 2500rpm).

I have checked and double-checked that I've got the firing order correct.

The engine seems to run smoothly and starts quite easily with no smoke and no excessive oil consumption. I have no idea of fuel consumption at this point.

It just seems to lack enough power to get me onto the plane.

All and any help would be greatly appreciated.

Thank you,

Shaun.


Quote:
Originally Posted by RicardoMarine
Same as any other SBC.
Keep in mind that how the distributor installation idexed the shaft, the rotor may not be pointing to # 1 when # 1 is at TDC C/S.
Is it NOT mandatory.... but does make sense to do it this way.

Chevy_V8_Firing_Order.jpg



progress.gif
 
Shaun, the image showing firing order is correct for the SBC engine.... auto or marine.
While I stated that it does not really matter where # 1 is on the distributor, it can help you in the future if you set this up as per that drawing! The distributor, wires, cap, rotor, spark plugs don't care.... but it can make it easier for you!
To correct this, the distributor must be lifted, and re-indexed!
Do this ONLY when the engine is @ TDC Comp Stroke # 1 cylinder!
This may involve rotating the oil pump drive so that the distributor can drop back into position!

Yes, the large "notch" when aligned with the TDC mark on the Harmonic Balancer, is your theoretical TDC for # 1. That is our starting point!

You mention "timing seems to be OK..."
All due respect, but this needs to be more than a "seems"!
What I see that may be hurting you, is the 14* @ 2.5K RPM.
14* would appear to be too little.... but read on, as we need to see what it is doing at higher RPM!

Something is likely out of whack with your progressive advancing system within your ignition distributor.
You should be seeing approximately 26*-28* of total spark lead @ approximately 3,100/3,200 RPM!
NOT @ 2,500 RPM! That is too early, IMO.

You should ideally see NO advancing until around 900/1,000 RPM.
Below this RPM, would be in BASE advance ONLY.

From 900/1,000 RPM, you should see a progressive spark advance up to approximately 3,100/3,200 RPM.
At approximately 3,200 RPM, you should be seeing approximately 26*-28* of total spark lead!
(I will NOT quote timing specs, so see your OEM specs for the exact number)

As for the un-even exhaust temps..... you'll need to examine things. Usually a restriction on one side causes this.
Could be Man-to-Riser ports..... could be other!
Could be the Riser-to-Ypipe rubber couplers being clamped over the scalloped areas of the Riser.
(these rubber couplers are typically too short.... and end up being clamped over this area!)
 
Last edited:
Hi,

The relative position of the distributor does not matter as long as the ignition timing for #1 cylinder is set correctly and the resto of the ignition wires are installed in the correct firing order.

Have you run a compression test? If you get low readings, I wouldn't be surprised if some of the lifters need to be readjusted (loosened). If they are too tight, the valves will not fully close.
 
Thank you very much for your replies.
I don't get much time to get to the boat, so it's a real disappointment when I do go and can't get the best from my boat. (I know it can perform so much better than it currently does).

It will likely be a couple of weeks before I can get back to it, and I have a full set of new HT leads on their way (The current ones are a couple of years old, so I decided to change these, just to make sure).

I will print out the suggestions, take compression readings, and check everything thoroughly, taking proper notes as I go.

I will be reporting back as soon as possible.

Thanks again! I really appreciate the help.

Shaun.
 
Although those Mallory's work fine, I'd take a good ol' Prestolite Marine with either clipdown or screwdown caps and put a Pertronics in it. Those Mallory aluminum arms are the pits after a couple years in the marine envioment.
 
Pertronix = Hall Effect
Mallory YLM = true VR (reluctor triggering)

If you like the Hall Effect, then go for it.

I don't! That is a P_ss Poor design, IMO! :mad:
 
Changing the distributor is something I did consider. The engine has the original contact breaker type of dist. with screw-down cap (I fitted a new cap) I can't remember what manufacturer it is. But, as I mentioned earlier, the ignition looked really steady when I used the strobe, so I reckoned it wasn't too worn. If I change the dist. for a new type won't I have to add a "box of tricks" amplifier or something, too?

Regards,

Shaun.
 
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