SOHC V6 Timing Chain Saga

[2000StreetRod]

Stuck with stock

The photo below illustrates why it is necessary to remove links in multiples of two when shortening the timing chain.

One link consisting of two sections of two metallic strips is attached with a pin to the next link consisting of three sections of strips - single outers and double middle.
I realized today that I can determine if removing two links is possible without taking apart the chain. A single link of chain corresponds to one tooth of the sprocket. So I installed the jackshaft and loosely attached the old rear jackshaft sprocket and chain. Then I just installed the chain on the camshaft sprocket shortened one tooth as shown below.

Next I tried to install the camshaft sprocket with the chain shortened two teeth (two chain links) as shown below.

Even stretched taught and with no guide assembly I could not seat the camshaft sprocket onto the camshaft. So now I'm convinced that shortening the chain is not feasible and I can proceed with assembling the engine using the latest Ford cassette as soon as it arrives.

 

[rileyrs]

wait quick question, wouldn't a larger diameter cam gear screw up the timing since it would turn the camshaft at a different speed than it should in relation to the crankshaft?

 

[CDW6212R]

Whoops, good call Riley, let's say that was a joke. LOL,

 

[shelbygt]

Sorry to hear this. I'm guessing, if you just changed the head gaskets, there is only one other way water is getting in there.......

How fast is the leak?

It is pouring in. If I start the motor and let it run for 5-10 seconds and turn it off, water streams out of the main muffler for a minute straight.

 

[2000StreetRod]

Not changing sprocket size

wait quick question, wouldn't a larger diameter cam gear screw up the timing since it would turn the camshaft at a different speed than it should in relation to the crankshaft?

I was not considering changing the sprocket size. The purpose of the exercise was to determine if a shortened chain would fit on the existing sprockets after eliminating the guide assembly.

 

[ranger7ltr]

Does anyone think a pressure test would be beneficial?

It is pouring in. If I start the motor and let it run for 5-10 seconds and turn it off, water streams out of the main muffler for a minute straight.

Before you tear it down to remove the head, do you think a cooling system pressure test with the cam cover off might show a head crack or similar problem? I have seen cracks in the ohv head go from around the valve seat area all the way through to the top of the head inside the vavle cover and I am wondering if that might be the case here...

Man the picture of the head definitely looked good but your coolant is obviously coming from somewhere and I am doubting the block is the source...

 

[2000StreetRod]

New rear cassette

The new rear cassette from Ford arrived today and is shown below.

As suspected, it only included the updated guide assembly, chain, jackshaft rear sprocket and right camshaft sprocket. There were no bolts even though the jackshaft rear sprocket retaining bolt is a torque to yield bolt and should not be reused.

I positioned the components for the photo in the approximate way they are installed in the engine. You can see the significant curvature of the traction side of the guide assembly which has no metal bracket support and has renewed my concerns about installing it.

 

[Glen4X4]

Its easy to replace Dale, don't forget to get the cap that goes into the block since you have to punch that out.

 

[2000StreetRod]

Examination of new chain

The photo below is a closeup of the new rear timing chain. It was made in Italy like my original chain.

The red arrows indicate the minimum amount (approximately 0.75 inches) that must be removed to shorten the chain. Each yellow arrow indicates a tooth position on the sprocket that corresponds to the shortened chain length. I again attempted to mount the stock chain on the camshaft sprocket with two links folded as shown in a previous post. This time I wired the two links together so they stayed in the shortened position on the camshaft sprocket while pulling the chain taught. I found that the distance from the centerline of the jackshaft to the centerline of the camshaft would have to be decreased by more than 0.25 inches in order for the shortened chain to fit. I suspect that even if I had a thinner head gasket and the head milled a small amount that the sprocket would not mount correctly on the camshaft.

 

[2000StreetRod]

Other parts received

Its easy to replace Dale, don't forget to get the cap that goes into the block since you have to punch that out.

Thanks for the reminder.

With the new cassette (PN 4L2Z-6M290-AA) I received the other related parts that I ordered: jackshaft rear sprocket retaining bolt (PN W703167-S430), jackshaft rear cover (plug) (PN F77Z-6026-AB), and guide assembly upper positioning bolt (PN F77Z-6U000-BA).

 

[Glen4X4]

Lol when I replaced the one on my replacement motor I didn't know I would need to plug/cap w/e is the appropriate term and had to run to the Ford garage right after installation.

 

[2000StreetRod]

New rear cassette tab

I ran into a problem while attempting to install the new rear cassette into my engine. There is a plastic tab near the lower end of the traction side of the guide assembly. At first I thought it was to keep the assembly in position by resting on a ledge in the head while inserting the guide assembly lower mounting bolt. However, after loosely installing the lower mounting bolt, I noticed that the tab was binding against the head casting and keeping the upper end of the traction side from being in position for the upper mounting bolt. I rechecked the part number (4L2Z6M290AA) and confirmed it was for the Explorer SOHC V6 from 1997 thru 2005. Tomorrow I'll pull the cassette assembly out and look for a notch or hole in the head for the tab to fit in. Maybe it's there and just plugged up with sludge. Fortunately, I did not torque any of the bolts so they can all be reused. I don't remember any of the assembly instructions mentioning the tab but I'll check all of them again. Has anyone else encountered a similar problem?

 

[Glen4X4]

I didn't experience any issues, mine went right into place.

 

[2000StreetRod]

All at same time?

I didn't experience any issues, mine went right into place.

Did you drop the jackshaft rear sprocket with chain and quide assembly down thru the opening in the head all at the same time? That seems to be the only way to get the pieces in. Did you install the guide assembly upper bolt or lower bolt first?

 

[Glen4X4]

I just did this not too long ago, I believe I installed the cassette then dropped the chain and rear sprocket down afterwards and honestly don't remember which bolt I did first. Sorry Dale wish I could remember exactly so I could help. I knew I shoulda wrote the assembly down for future reference.

 

[2000StreetRod]

Second attempt successful

I pulled the right cassette out and scraped some sludge coating off the head casting. The red arrow in the photo below identifies the tab that was causing the installation problem.

I pushed the jackshaft forward and tried again to install the cassette. After several minutes of twisting back and forth it finally dropped into position. Since I reused the guide assembly lower mounting bolt I was concerned that the O ring might leak so I applied some non-hardening gasket sealant to it. I may have trouble removing it when I rebuild my engine.

 

[CDW6212R]

Clean an old o-ring like that well, and use Ultra Black. That will seal anything like that.

 

[2000StreetRod]

Front cassette, accusump & exhaust bolt

I've been busy with spring yard work and have been neglecting my timing chain work. Today I finished cleaning the valve train area of the left head and inserted the new guide assembly. Even without the chain and sprockets I had to force it a little to get it thru the opening in the head. After threading the chain thru the guide assembly and engaging the sprockets with the chain I torqued the guide assembly lower mounting bolt. Then I coated the upper mounting bolt O ring with non-hardening gasket sealer and torqued it in position. Tomorrow I'll begin installing the primary chain components.

A couple weeks ago I bid and won a new Canton Racing electric valve kit at about half price. Today I ordered a new 3 quart Accusump and mounting brackets. I'm hoping to find a way to fill and pressurize the Accusump and then pre-oil the engine before start up (assuming I manage to get it back together correctly). I don't like the idea of starting the engine after sitting for 3 months and being flushed with Gunk engine flush without pre-oiling. I'll have to close the Accumsump valve after pre-oiling because the engine pre-lube will clog the cylinder the same way it clogs an oil filter.

I was not able to loosen the bolt I cut off to the exhaust manifold downpipe with locking pliers. I refuse to drill out the bolt and lose the threads in the manifold so I'll probably remove the manifold from the head and have a welding shop weld a nut to the bolt shaft.

 

[CDW6212R]

Do make a thread on that pre-oiling project. For nice cars I'd like to do that if possible. The electric Mallory pre-oiling pump is the only one I've seen to do that, and it's obsolete.

A remote mount turbo requires a pump to return the oil, I wonder how much those are?

 

[2000StreetRod]

Next project & thread

I was really surprised at how fast Summit Racing shipped my Accusump and mounting brackets. They arrived today as shown below with the previously received solenoid valve.

Installation of the unit and a thread to go with it will be started as soon as I get my engine reassembled and installed.