SOHC V6 Timing Chain Saga

[2000StreetRod]

Cam advanced timing

. . .
2000StreetRod - Forgive me..You may of already went over this. When you timed your cams, did you use a degree wheel and advance the timing 2 degree's?

No, I went with the stock camshaft timing. Do you recommend advancing the timing? If so, what are the benefits?

 

[Jakee]

I can't say I recommend because I haven't done it myself.

There was a discussion going on in a mustang forum where the guys were saying a problem (low HP) experienced, from another that just built his engine, was because he was using "re-grinds" , timed with the ford timing tool kit but didn’t use a degree wheel to advance. From what I gather, the ford timing kit places the timing right at zero, no retard, not advance. And the "re-grinds" were recommended to be set 2 degree's advance (probably a variable for each re-grind cam (small mistakes grinding)). This may be only for the re-grinds but it got me thinking. I did a little searching and found others saying changing the cam timing on the SOHC will move the power band up or down. Advance supposedly moves it down. I knew of this from the popularity of doing for OHV engines but wasn’t sure how it effects the SOHC engine. Supposedly, doing this on a DOHC engine can move the power band and the Torque curve.

So I’m not 100% positive it will do anything good although I have heard rumors it can improve gas mileage because of moving the power band down so you’re in it longer when street driving. It could be just snake oil so be ware. Also, if I wanted to try something like this, I would be sure to check valves in relation to the piston. If not timed correctly you can get contact; even if you don’t feel contact during engine assembly.

 

[CDW6212R]

Moving the cam timing does alter the power band, basically pivoting it around the torque peak rpm. Aftermarket cams often recommend that based on the intended design versus the specific vehicle. Checking the cam timing is critical for any aftermarket cam due to the poor quality control of almost all of them. For details research the quality of a SADI cam versus a billet cam. SADI cams almost never match the specs, and basically never have identical lobes. Billet custom cams almost never need altered timing because they basically match the specs or are destroyed and a new one is built. Plus the lobes will be virtually identical, so the timing for each cylinder is the same.

Those are the big unseen upgrades of a billet cam. You can't degree a SADI cam using different lobes, the resulting valve timing will change for each lobe. With a billet cam, you can time it with any pair of lobes and the timing will stay the same. Does that make it clear how poor an aftermarket SADI cam is? BTW almost all OTS cams are SADI cams, thus my harsh conclusion to never buy an OTS cam.

For the stock SOHC it is likely best to time them straight up. Only if you had exact before testing of times and timing could you do useful after testing to figure out which would be best for a given vehicle. Most of us here know of Al's high mileage truck, if possible I wish we could find out what his exact valve timing events are. I think much of his great fuel mileage is from his cam timing. Regards,

 

[2000StreetRod]

Advancing cam timing

On my Alfa DOHC 2600 Spider the camshafts and sprockets were splined which allowed independently changing the intake and exhaust timing relative to the crankshaft. One obvious disadvantage of the SOHC V6 is that changing the intake timing also changes the exhaust timing and vice versa.

I have found very little documentation on the actual camshaft timing. 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. I don't recall the definition of advancing and retarding the camshaft timing. I'll have to do some research before I can make an informed comment. With my broken rear chain guide I suspect that my right bank timing was several degrees retarded from stock. That might explain some of the fuel trim differences between the left and right banks. The SOHC V6 is prone to an unstable idle. I decided to see what the restored stock timing would provide in idle stability, fuel economy and performance before trying something different.

Once I have learned more I may consider changing the timing during my rebuild. I'll make sure that I know what the piston to valve clearance is for any change I make.

 

[cjmedina]

Dale, you might want to upgrade that when you rebuild. The later model SOHC got a revised upper and lower housing, which is much cheaper and different sensors which mount differently.

Search for the threads here where others came up with a great solution for the older SOHC. You can buy the cheaper upper housing from aftermarket sources, and make it work with the older lower housing. What I remember is that they bought the newer sensors and the clips to install them, and removed the bolt hole sleeves which are for the newer lower housing. So you end up with all the upper parts new and mount them on the old lower. I think the parts total was under $100, say $60 for the lower housing plus the sensors and clips.

My SOHC had no leaking there and I never loosened those sensors to work on mine. If they are never touched, they may last a long time.

You can use the upper housing but you need to remove the bushings, The whole upgrade including buying the clips from Ford is about $100. This way you don't have to worry about it cracking in the future.

CJ

 

[2000StreetRod]

Engine lift points

Today I applied dielectric grease to the spark plug wire and ignition pack boots and then installed the wires. It was then time to transfer the engine from the stand to the crane. I began looking for engine lift points that would result in the proper center of gravity and not damage my newly painted exhaust manifolds. I came up with those identified by arrows in the photos below.

CAUTION: It is important to prevent the engine lift chain from slipping in position when the engine is tilted.

Identified by the arrow in the photo below are removable chain links that attach the engine support chain to the crane hook chain. I did not use the actual crane hook. The links prevent the support chain from slipping in either direction.

The next task is to replace the rear main seal.

 

[cjmedina]

On my Alfa DOHC 2600 Spider the camshafts and sprockets were splined which allowed independently changing the intake and exhaust timing relative to the crankshaft. One obvious disadvantage of the SOHC V6 is that changing the intake timing also changes the exhaust timing and vice versa.

I have found very little documentation on the actual camshaft timing. 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. I don't recall the definition of advancing and retarding the camshaft timing. I'll have to do some research before I can make an informed comment. With my broken rear chain guide I suspect that my right bank timing was several degrees retarded from stock. That might explain some of the fuel trim differences between the left and right banks. The SOHC V6 is prone to an unstable idle. I decided to see what the restored stock timing would provide in idle stability, fuel economy and performance before trying something different.

Once I have learned more I may consider changing the timing during my rebuild. I'll make sure that I know what the piston to valve clearance is for any change I make.

Dale,

Could that be why I was having the po171,174 codes and why the engine was breaking up at 3700 rpm yet I had good vacuum? My chain was off since I got this truck.

Cliff

 

[CDW6212R]

Dale, when you get to the point of the rebuild, you might check on a custom set of cams. Depending on your use, fuel costs, and how long you keep the truck, it may be feasible. I know they would not be cheap, a common V8 cam is about $400. For a simple build and unimportant truck it's not worth it. But if you might keep it long enough to appreciate an extra 25HP or mpg, smoother power band, maybe it's not outrageous to think about. I'm stuck on the pushrod V8's and their reliability and parts sources. But I do appreciate the attempt of Ford in developing this SOHC.

 

[CDW6212R]

How long will it be until you do rebuild it? If the rear seal is actually dry and it won't be too long, driven regularly, I'd leave it most likely. It's easier to install them when the main cap is off and you can get the whole area really clean. It's not so much fun or foolproof when the main cap is on.

 

[Jakee]

I did find this..

"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."

 

[cjmedina]

Today I applied dielectric grease to the spark plug wire and ignition pack boots and then installed the wires. It was then time to transfer the engine from the stand to the crane. I began looking for engine lift points that would result in the proper center of gravity and not damage my newly painted exhaust manifolds. I came up with those identified by arrows in the photos below.
View attachment 59158
View attachment 59159
View attachment 59160

The next task is to replace the rear main seal.

Dale that looks like good lifting points
Cliff

 

[2000StreetRod]

Super Six Motorsports regrind cams

Dale, when you get to the point of the rebuild, you might check on a custom set of cams. Depending on your use, fuel costs, and how long you keep the truck, it may be feasible. I know they would not be cheap, a common V8 cam is about $400. For a simple build and unimportant truck it's not worth it. But if you might keep it long enough to appreciate an extra 25HP or mpg, smoother power band, maybe it's not outrageous to think about. . .

Super Six Motorsports has regrinds available with intake duration 211 degrees @ .050, exhaust duration 211 degrees @ .050 lift, intake valve lift .500”, exhaust valve lift .500”, and lobe separation 112 degrees. The cams were available as a set including a specific drivers side and passenger cam. The cams require a custom retainer, valve seal, and spring kit. I don't know if they are worth the cost and effort. The price is $575 minus a refundable $125 core.

 

[CDW6212R]

That's good information to hear. I would ask Jay of Camshaft Innovations, if he would make a custom billet cam pair, for a fair price, I'd jump at those if the SOHC was my "motor." I just think they will be a good bit more than a normal rebuild, also noting that he should be sent the heads and asked to build them. Part of his magic, and any top custom cam, it's in the head assembly. A custom cam can be designed to purposely function with better stronger springs, because he is an expert at knowing the limits of those parts. If he let him do it all, complete heads and cams, the results are often amazing. That's about as much as I can brag on it without exaggerating. He did my 347 heads and cam, I expect the truck to be very quick NA. Regards,

 

[2000StreetRod]

Leaking rear main seal

How long will it be until you do rebuild it? If the rear seal is actually dry and it won't be too long, driven regularly, I'd leave it most likely. It's easier to install them when the main cap is off and you can get the whole area really clean. It's not so much fun or foolproof when the main cap is on.

I believe the rear main seal is already leaking. I was unable to determine if it was the seal or the block cradle gasket. The rear main seal is more likely. Other forum members have replaced their leaking seals only to have them leak more. I don't have Ford's special tool to install the new seal. I'm going to attempt replacing the seal and if the new one leaks then I'll just put up with the leak until the rebuild.

 

[CDW6212R]

Very good, that's what I'd do. I prefer to replace engine and trans seals whenever possible. I've never done that rear seal myself, but I've helped a friend and heard the stories. During a normal engine build it's simple, but that kind needs a little more attention.

 

[2000StreetRod]

Rear main seal replacement preparations

The photo below of the old crankshaft rear main seal attempts to illustrate that there is a variation in the upper and lower sections of the block where the seal fits.

My Haynes manual specifies that the seal should be perpendicular to the crankshaft axis and that the tolerance is 0.015 inches. Many members have experienced leaks after replacing their rear main seal. I suspect that they may have tried to seat the new seal flush with the nonuniform block surface.

The photo below shows my seal installation tool. It is a 2 inch schedule 40 PVC coupling. The coupling inner diameter is the same as the outer diameter of the crankshaft. The coupling outer diameter is less than desired but adequate.

I used a drum sander to enlarge the coupling inner diameter until the crankshaft sleeve provided with the seal kit fit inside of the coupling as shown in the photo below.

I drilled two small holes where the "dimples" are on opposite sides of the seal. I was careful not to go any deaper than when the drill broke thru the seal. I used a new drill bit so it would not "walk" away from the dimple and endanger scoring the crankshaft. After drilling the holes I inserted two hex head sheet metal screws as shown in the photo below.

 

[CDW6212R]

Don't use the sleeve unless the crank surface is grooved some. Do you have a seal puller, or a cheap 3/4" socket set? A seal puller should yank that out in short order. The socket set is great for installing seals, one socket usually fits what you need.

For that main cap that protrudes beyond the block, I think I'd find a part to use to install the seal evenly. If you can find a piece that thick to be a "shim", just something to lay along the top to check with, hammer the seal in until it's close. Check the evenness with the "shim" setting just above the crank on the block. The seal should then be level with the shim and main cap below. Interesting.

Place a thin film of Ultra Black RTV where the seal seats before installing it, with plenty on the cap/block seams.

 

[2000StreetRod]

Replacing rear main seal

I used a small pry bar as a lever as shown in the photo below.

The old seal was easy to extract with the pry bar.

I inspected the crankshaft for wear to determine if I needed to use the sleeve. I found some crud accumulated on the surface but no indentation from the seal rubbing.

I cleaned the crankshaft surface with a thick cloth soaked with solvent folded over the end of a small flat blade screwdriver. I was very careful not to poke the screwdriver blade thru the cloth and scratch the crankshaft surface.

I applied engine oil to the inner and outer surfaces of the new seal and placed it in position. Then I used the coupling and my 4 pound hand sledge hammer to tap the seal gradually and evenly into it's seat. I used the short end of an allen wrench as a "feeler gauge" to compare the distance from the end of the crankshaft to the seal. The installed new seal is shown in the photo below.

 

[BobWiersema]

Engine Lifting

Dale,

With this setup you just saved yourself about $315.00 so go buy yourself something nice.

Ford Tools

Bob

 

[Jakee]

I'm sure the chain you used has plenty of strength you need to lift the engine. But for anyone out there that wants to copy, please make sure your chain is no smaller than what you see in the picture above. 7/16” ??

I can't help but notice the chain is loaded on 1 link up top. If that link breaks, you’re in trouble...

Now with the other set-up, you're dividing the weight of the engine. Instead of all the weight on 1 link, you have it divided in half which will more than likely take twice the load.

Again, I don't think the 7/16" ?? chain you used is going to snap, but from an engineer's stand point, and a safety look, the other set-up could be worth something if you ever find yourself trapped on the floor with a 4.0 SOHC on your chest.