Advance or Retard SOHC after hydrolock

[Sedition]

Firstly I feel that some background information is required to help understand, "why?"

I hydrolocked my Explorer during a flood, It stalled 20 feet after exiting the flood water. I hit the key just once and only enough to partically charge the coil in the starter confirming in my mind a hydrostatic lock. I had it towed home, did the usual - plugs out, hand crank engine over, drop oil and filters out and replace - then I decided to crank the engine over with the key to blow out any water remaining in the cylinders.

Turns out there was a little more water still in there then I had anticipated. As I turned the key It sounded normal for about 2 seconds then "CRUNCH!" I immediately realised that I had just shattered the rear timing chain guide.

I dropped the oil pan and removed the timing case to confirm the condition of my guides and tensioners and to remove all the broken pieces. There was no metal in the pan. The traction side of both camshaft to jackshaft timing chain guides are still intact and looking good. The tension side guides are completely missing/destroyed. The primary guide and tensioner are in good condition. The tensioners seem to take up the slack in the traction side of the chains to compensate for guide not holding the chain in a "kidney" shape.

I then put her back together and start her up. She run ok with a little idle tremor and slightly reduced torque. I had to know what was up, I was suspicious of the timing being out on the right camshaft seeing that I had just shattered its guide. I also noticed that about half the time I turned the engine off and listened real hard, I could hear a slight "hiss" into the exhaust on the right bank just as the motor stops turning.

I did not feel like pulling the engine just to replace a timing chain cassette. Mostly because I do not have the engine pulling equipment required.

I removed both valve covers and noticed my right camshaft was 12 degrees Retarded relative to the crank and left camshaft. I decided to set the right camshaft back to TDC with the tension side of the chain tight. After putting it back together again I start her up and strait away it sounded tractory as hell (my best guess is valve spring pressure may be rolling the camshaft forward). I immediately turned it off and reset the cam retarded by 5 degrees. Set at 5 degrees retarded the performance is how I remember it although it does sound a little different at certain RPM's.

Now my question to you is, Would you retard the left cam by 5 degrees to synchronize both camshfts? or try and find the limit of how close I can get to TDC on the right camshaft without the motor sounding tractory?

Anyone's opinion or factual information is most welcome...

 

[my98nnj]

Get the timing tool and set it right.

 

[2000StreetRod]

equal timing

The stock cam is a dual pattern cam which is desirable when the intake valve (1.81 inch) is larger than the exhaust valve (1.54 inch). The duration of the exhaust lobe (193 degrees) is greater than the duration of the intake lobe (185 degrees) to allow a comparable amount of exhaust flow thru the smaller valve. According to Super Six Motorsports the stock intake duration is 185 degrees @ .050 and the exhaust duration is 193 degrees @ .050. Valve lift is .472 inches with 116 degree lobe separation.

According to an article Isky racing cams have their best overall performance when timed for the split overlap position. The article states

"Split overlap means that the intake and exhaust valves are equally open at T.D.C., although the intake valve is opening and the exhaust valve is closing. Also this means that the intake valve opens the same number of degrees before T.D.C., as the exhaust valve closes after T.D.C. A cam in the advanced position would have its intake valves open further at T.D.C. than the exhaust valves, and also open at a greater number of degrees before T.D.C. than the exhaust valves close after T.D.C. Conversely, a cam in the retarded position would have its exhaust valves open further at T.D.C. than the intake valves, and also close at a greater number of degrees after T.D.C. than the intake valves open before T.D.C. "

The article also states during valve float at high rpm the closing exhaust valve when the piston is rising is the most likely valve to contact the piston.

Isky racing cams are designed to be 2 degrees advanced when installed to compensate for future timing chain stretch retard.

Jakee found the following on the internet: "the real reason advancing the cam will improve low end. It's because the intake valve closes sooner, trapping more mixture at low r's. But it's a double-edged sword. What you gain on the bottom, you give up on the top. If you are happier with the bottom with it advanced and can live with the way it performs on the top, then you've probably overcammed the motor in the first place.

Advancing the cam will reduce the intake valve to piston clearance and increase the exhaust valve to piston clearance. Retarding the cam will increase the intake valve to piston clearance and reduce the exhaust valve to piston clearance."

He also said some of the Mustang SOHC V6 owners advance their cams 5 degrees.

I think having both banks timed the same will improve idle smoothness and probably result in a more uniform power pulse at all engine loads. I did not choose to advance my camshafts since that would decrease piston to closing exhaust valve clearance.

 

[Sedition]

Get the timing tool and set it right.

I am confident in timing the SOHC engine without the timing tool set. I have other ways of holding the cam & crank shafts that allow me to time this engine to TDC or any other position desired.

I thankyou for your input.

 

[Sedition]

With all the information I have taken in today I am thinking of setting a 2 degree retard in both cams relative to the crank.

Firstly to sychronize my camshafts relative to each other for a smoother warm idle.

Secondly I would like to acheive a slightly higher torque curve at over 3000rpm (that point where the intake runners change shape).

Correct me if I am wrong in thinking this.

 

[Sedition]

Retardation underestimation

After a few days I have decided that I am not happy with the torque curve at 2 degrees retarded, there is a nice flatspot right before 3000RPM... Tomorrow I'm going back under the hood for another re-time. I think I will just set my camshafts at TDC instead of trying something different again. Perhaps last time at TDC I had my ignition leads crossed up or had made some other "silly" mistake causing the "tractory" sound to eminate from my motor.

 

[2000StreetRod]

Vis

Make sure that the Variable Intake System (VIS) lever arm on the intake manifold moves freely. Carbon builds up internally from the EGR. Also make sure the rod from the vacuum motor to the lever arm is connected. Some members have found the rod laying loose on top of the engine. Ford eliminated VIS on the 1999 and later models because the reduced reliability was not worth the small performance improvement over fixed intake runners. There were too many drivers who never let the engine speed exceed 3,000 rpm.

 

[Sedition]

Vis

I was able to test the VIS whilst under the hood, it functions perfectly. At the moment I have my truck stripped down to the camshafts. After I eat something I will then position my camshafts at TDC and adjust my crank to suit.

The best thing about not having the timing tool kit is that I can hold both the camshafts with vice grips at TDC, or anywhere else for that matter, at the same time.

I plan to test the cams with the starter motor before I put it back together, hopefully it does not splatter too much oil around my engine bay. Hopefully they turn smooth with no hesitation or pulling back and forth whilst being observed. keeping in mind I have a right hand drive model enabling me to directly observe the right camshaft whilst reaching in the window to turn the key.

Please note: the engine cannot possibly start whilst performing this adjustment as the coil pack has been removed from service.

 

[Sedition]

Good sign

After the re-adjustment (TDC all round) I turned the key and just let her crank for a good 20 seconds. The right camshaft rolled perfectly. It may interest you to know that when cranking it over I observed a stream of oil connecting the cam lobes to the oiling rail. The oil streams also ran down onto the exhaust manifold, not too much though, yet enough to smoke on start up until the oil is burned off.

Now to put her back together, correctly. Then for the moment of truth.

 

[Sedition]

All good

I turned the key, it fired first go with no tractory sound. I went for a half hour test drive, everything just works better at TDC. Its almost as if everything else in the truck was designed for this engine at TDC, tranny even shifts smoother.

 

[Sedition]

Wild Goose Chase

So it turns out that the "Tractory" sound was due to no oil at the camshaft tensioners. The new oil had to fill the oil pickup, oil pump, oil filter, oil gallies ect... before reaching the camshaft timing chain tensioners. I just turned the engine off before the oil had a chance to get there for fear of engine damage.

All the time after the hydrolock I had the oil out of the pan whilst removing broken guides, retiming camshafts and rotating the crankshaft. This caused the oil to drain out of the system. What I should have done at the very least was filled the new oil filter with oil before installing and proceeded to rotate the crank by hand to get the oil to where it had to be.

I found this out after a recent oil change when I failed to prefill the oil filter and got that tractory sound for a few seconds just before I almost crapped my pants.

I regret nothing as I have learned so much about the dreaded SOHC engine that most people including mechanics seem to dislike. By working on this engine and subsequently the truck itself I have been filled with confidence in both my own abilities and most importantly the reliability of my daily driver.

 

[2000StreetRod]

thanks for the report!

It's good to know that the engine runs best in your Explorer with the camshaft timing set for TDC as designed. That saves me from experimenting with the timing. I've always prefilled my replacement oil filters since becoming aware of the spring/hydraulic tensioners. The timing chain is most likely to slip when the oil pressure is low.

 

[Sedition]

Oh Hell No!

I have been going over my engine for the last few nights as I had a few problems pop up such as a water leak, vacuum leak and a rattle in the engine to chase down.

I removed the front timing cover to repair the water leak and found what was making my engine rattle. The balance shaft tensioner has broken.

After a compression test I had only 105psi on cylinder no#2. I suspected valves so I removed the head only to find that the no#2 cylinder does not completely come to the top of the block on it's travel. I guess this is the cause of low compression in this cylinder.

I know the crank shaft is strait, the harmonic balancer doesn't wobble at all. So my best guess is I have a bent connecting rod. Looks like I will be pulling the motor for this one.

Cylinder no#2 covered in burned oil. the piston sits about 5mm from the top of the block at it's TDC position. You can also see my rear timing chain with no guide, I may as well put in a new timing chain kit while I have the engine out.

On closer inspection the valves and stems look ok, I'll give the heads a good polishing in the mean time.

I can't believe it, You can actually stand in the engine bay while you remove the heads. I love American Vehicles!

 

[CDW6212R]

I am confident in timing the SOHC engine without the timing tool set. I have other ways of holding the cam & crank shafts that allow me to time this engine to TDC or any other position desired.

I thankyou for your input.

I like it, you have figured out how it all works.

I do suggest using a better tool for setting the crank though. The TDC tool and kit are not very accurate. I suggest using an actual crank timing dial, and a piston stop to determine true TDC. With the dial attached to the crank, you can set the timing far more accurately. Those are not expensive either, maybe $50 total. Well worth it, because they work on most engines.

 

[Papa]

Sorry for your troubles, hydrostatic lock in any engine can produce extensive damage. Collapsed pistons, blown head gaskets, lifted injectors, bent or broken crank shafts and as you have discovered bent connecting rods among the other things that can go wrong. This is why on large engines it is standard operating procedure to bar the engine over manually with the blow downs open to purge any oil, fuel or water from the engine or in your case spark plugs removed to prevent further damage. Hopefully you can capitalize on your opportunities during the tear-down and rebuild.

 

[mr_valingo]

I've hydrolocked my ohv twice now. The first time i got lucky, no damage. It actually ran better. My rough idle went away. The second time, however, i pulled the plugs and spun it over. I could already hear knocking. Got it fired up and she was tickin away. Drove home then to work the next day and changed the oil. No change. I dumped lucas in and 900 miles later it still runs. I suspect its a crank bearing. Gonna drive it til she blows then swap the motor and do it again