3.2SS Rebuild - Way down on power
 

I'm in the break-in stage of my 3.2SS and the engine is way down on power.. Here are the engine specs:

'79 SC 3.0 Case
Mahle Max Mortiz 98mm 9.8:1 P&C
DC20 Cams
Megasquirt EFI

The left bank, 1-3, is generating heat and all the plugs look good.

The right side, 4-6 does not get hot, the exhaust is cool and the plugs look like nothing has happened - although heavy gas smell.

I tested for spark and 4-6 is getting spark. I tested the wires, all test 4 ohm resistance and look good. I tested for fuel by pulling the fuel rails on both sides and both eject the same amount of fuel (I had the EFI working on the engine before doing the rebuild).

I'm thinking the right side timing is off. I'm a newbie at this. Do these symptoms suggest this is the problem???

thanks,

-Rob

Have you checked for compression of the right side?

No I haven't. The entire right side is behaving the same way - all the plugs look the same.

Obviously worth checking though.

Alphie, I'm a relative new-guy, so I speak cautiously. Perhaps you are correct in your assesment that the timing is off, since the problem exists for the entire right side. Relatively easy to check. I'll hope some of the regular guys will chime in and give you some more, and perhaps better advise.

thanks, I hope to hear from some regulars too.

This rebuild has taken a huge mental toll on me!

I would say that ign timing is the most obvious potential culprit...and by far the easiest(and cheapest) to adress.

Put a timing light on it and make sure all is where it should be.

If that checks out, i'd check the valve timing on that bank next.

Check for cam timing 180 out.

I've verified ignition timing with a timing light. The car runs, revs, idles, just very low on power and the right bank doesn't seem to be working.

cam timing

Explains Everything
 

My right side off 180 would explain so many things. Aside from the right bank not burning fuel, it would also explain why the engine is so hard to turn by hand.

I took out my SC cams and wrote a chart of intake valve behaviour as the engine goes through a 360 stroke.

Since the camshafts turn at half the speed I came up with the following.

S - Start of valve spring compression
C - Valve spring compressed
O - Off (no valve spring compression)

Stroke Left Bank Right Bank (Correct) Right Bank (Off)

0 1 S 4 C 4 O
2 O 5 O 5 O
3 O 6 O 6 S

60d 1 S 4 O 4 O
2 O 5 S 5 O
3 O 6 O 6 C

120d 1 C 4 O 4 S
2 O 5 C 5 O
3 O 6 O 6 O

180d 1 O 4 O 4 C
2 S 5 O 5 O
3 O 6 S 6 O

240d 1 O 4 O 4 O
2 C 5 O 5 S
3 O 6 C 6 O

300d 1 O 4 O 4 O
2 O 5 O 5 C
3 C 6 S 6 O

In correct timing, every 60 degrees shows that one valve is starting to open and one valve is open, the rest are closed.

When its off 180d then you get times when TWO valves are starting to open or TWO valves are open. This would result in much increased resistance to hand cranking. And at one point you get just one valve starting to open while all others are Off resulting in VERY little resistance. This is exactly what I was experiencing.

Hi Rob,

I can't help you with your problem, but was interested in the 3.2 setup wit MS efi.

Was is the output in hp, on this engine (when it is as it should bee)..? what kind of intake/exhaust system are you using ?

Thanks Roslin

Roslin,

Check out BITZRACING.com for the kit. It uses the stock CIS. You can remove lots of pieces and convert the airbox or leave it as is.

The exhaust is backdated '74 heat exhangers with a dual in one out muffler.

Expected hp? Right now I'd say its running about 120hp! With the engine at optimum I'm not sure. Hoping for 230 or so.

-Rob

alphie,

Unless there is something about your set-up that is way different from mine, you can check the cam timing with the engine in your car. I did it after my rebuild, and checking the cam timing, start to finish, was about 15 minutes. Less time than I will spend writing this:

Remove your distributor cap and set the crank to TDC with the rotor pointing at the position where plug wire position #4 should be with the distributor cap on (180 degrees away from #1).

Remove the upper valve cover on the right side.

Set-up your z-block and dial indicator on #4 intake valve.

Set your dial indicator to read zero (#4 intake should be closed)

Roll the crank over (clockwise) about 300 degrees (less than 360 degrees - your dial indicator should not have moved from zero).

Continue rotating the crank while watching the dial indicator. It should show the intake starting to open. Keep rotating until the dial indicator gets to the correct cam overlap specification for your engine/cam combination. You should be at TDC with the rotor now pointing at plug #1 position on the distributor cap.

If the above procedure is followed, and everything is correct - it's not your cam timing - but it sounds like cam timing to me. There is something about the above procedure that was not done correctly. Double check your distributor wire orientation and your cam timing - both easy to check, and easy to not get correct. This should get you back your lost HP.

Best of Luck

I just confirmed it. Set #4 to TDC and popped the right side intake valve cover. The intake valve for #4 is at full compression and I believe it should be 180d so that #4 valve spring is NOT being compressed.

Now the question, can I reset the timing with the engine in the car or should I drop the engine for the 3rd time!

Living up north its getting harder and harder with the cold weather!

Again, I'm not sure how much stuff (A/C, intake, heater hoses) that you have in the way - you may have to remove your muffler. On mine - with the motor in the car, I can remove the rear engine tin piece, and remove the right side chain housing cover - and your ready to remove the cam nut. I'd give it a try - If you can't get to it, then remove the engine. But I'd bet you can do it in the car.

Thanks, I'm getting close.

I don't have AC anymore. I took off the muffler and pryed out the rear engine tin. Just in the process of removing the camshaft housing cover.

-Rob

I do not envy you right now my friend...but i will once you get it fixed and are tearing ass around town.

Good luck!

It's got POWER!!!
 

Fixed the timing with the engine in the car. Wasn't that hard actually.

First off, now I can turn the engine over with the fan belt pulley - couldn't do that before.

Secondly, the engine REALLY spins with the starter - instead of sounding like a tractor.

And finally, its got TONS of power. I still need to tune with fuel mappings, etc, but holy CRAP it ROCKS!!!

Now I can sleep peacefully this winter and dream of 915 upgrades... :)

Glad you found the fix! Congrats, now don't baby it too much.... :)


Cheers

Glad to hear it worked-out Alphie.