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1996 351w - Timing Chain replacement choices & should I advance the OEM cam timing?

jimtmcdaniels

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Hi,
Any advice please on timing chain replacement selection AND if at the same time, advancing the cam timing can improve OEM cam mpg & power without any trouble?:

Vehicle:
My stock 1996 Ford ClubWagon E350 extended body w/stock 351w & towing package and highway axle ratio of 3.54. I plan on keeping my van for many years.
I live and operate mostly at 6,000 Ft here in Colorado, used for personal use, road trips and seasonal towing of a 3,500 Lbs trailer.

Situation:
I see the OEM dual roller timing chain definitely has some slack(I’m in the middle of replacing the timing cover gaskets and water pump gaskets because of leaking coolant from gaskets).

SO I suppose I really should replace the chain while I’m in here.

But:

1.
I’m looking for advice/to choose either just a new chain OR new chain w/ crank & cam sprocket kit.
Brands quality seems can be questionable and places like rockauto have a large confusing selections where beefier ones or racing ones seem like a good idea but only the pros are mentioned, what are the cons?.
I don’t know the quality of the OEM parts to compare to the aftermarket offerings.
Also I don’t know for sure which chains are compatible with the OEM sprockets if I reuse them..
I do know there might be chains that won’t stretch as fast as my OEM chain has.
Seems brand Cloyes has more offerings but quality has gone down(more made in China). Melling brand seems to still be quality.

Rockauto has a hand full of offerings.

Looking at price differences, it seems the best offering without a large price jump is the Cloyes high performance Street true for only $2 more than their standard or heavy duty offerings.
I'm slightly suspicious from experience with manufacturers not being forthcoming with the cons of a particular product.
I mean like is it possibly overkill in that it may require cover altering or is noisy or too heavy.

2.
Also, I see some of the kit’s crank sprocket has several key holes to advance the cam timing:

AND I've read on some forums posts they strongly recommend advancing the cam timing, stating that most OEM cams(including late model vehicles) are retarded about some 4 degrees, for minor emissions reduction.
But that sadly this OEM cam retard also reduces our engine’s mpg and power, sometimes considerably..
Yet other forum posts say this is not true or only for certain engine years.
So I don’t know where my 1996 351w.might be in this consideration.
It is said that often Street level aftermarket cams are 4 degrees advanced by default.
Also that advancing the timing moves the HP and Torque peaks down to a lower RPM which is desirable for take off and street use.

I did find what seems a wise hotrod site, said to simply do a compression test on a cylinder(cranking with the factory cam timing setting).
Then take new readings after in 2 degree increments, advance (or delay) and find the timing setting with the highest compression and go back to that highest setting for the best mpg and power.

Ok so any wisdom is very welcomed so I can move forward successfully..

Thank you

Jim
 

7mopar

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I think the wise hotrod site would not be an option for me without knowing were cam timing was set at the factory. But that would require a good timing chain and gears, degree wheel and a piston stop. Poking holes in pistons or bending valves would not be much of an improvement.
 

65 sporty

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7mopar

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Summit has a bunch of offerings. I would change the set, not just the chain. I have never tried advancing the stock cam in one of these engines, but any help in mileage would be welcomed I bet.

I was hoping you could shed more light on this than I could. I have not had a 351w opened up since the mid 1970's. I sure would not have recommended advancing the timing to far then on count of valve clearance. Am not sure about the newer stuff.

Just replacing a chain without the gears has never been a good idea. If the chain is worn the gears are to.
 

jimtmcdaniels

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Thank you for your discussion and advice!

Well I did go ahead and replace the timing chain and sprockets months ago with the Cloyes Street True that has in the crank sprocket, 3 keyway notches which allow factory timing or advancing or retarding by 8 degrees which translates to 4 degrees at the camshaft. This is a very affordable set and is an upgrade from the oem, should last perhaps the life of the engine.

I choose to set at the advanced position and thus far, I am glad I did.

I got conflicting answers from people on whether I should.

I called the timing chain companies and some said to advance, since since the early 1970's, cam/crank timing has been retarded, sacrificing some performance, for some improved emissions and that many after market cams have a 4 degree or so advance in them to reverse this factory retard.

Others said not to advance, keep it oem.

Others said they had advanced timing considerably more than 4 deg (using a sprocket that allows for more advance) as experiments into increased mpg and that it worked for them. Even saying to advance while crank compression testing and set at the advance setting that gives the highest compression psi.

Others said advancing is a popular practice with the 300 c.i. ford engine and that it can help with driving in high altitude's thinner air.

The air is thinner here where I live at 6K altitude.

Others warned about potential preignition problems and about starter problems because of the increase in compression making it harder for the starter to crank

I do believe I hear a hint of perhaps a struggle from my starter upon starting.... or it's my imagination.

Before I advanced the timing, I did a cranking compression test on one cylinder and then after with the new advance and found the compression increased 27 psi on the same cylinder, due to the intake valves closing sooner on the upstroke.

This also noticeably increased the torque when accelerating. From a stop making a right turn I can now squeak the right tire some where before I could not.

I can't say anything about mpg change as the gas tank had a leak I repaired as well.

This cam timing advance is suppose to move the torque and hp peak occurrence to a lower rpm, I think about 300 rpm I read.

This is fine because it will still accelerate to redline as before, I can't say I can tell the difference there and this should help with towing and perhaps mpg.

When I first started the engine, it knocked bad, until I retarded and reset the ignition timing.

It was off because of the new chain without any slack and the cam advancement, advanced the distributor ignition setting.

Since my 351 design doesn't have a knock sensor, I popped open the van's doghouse and drove around for a bit so I could really hear the engine when going up a hill and heavy acceleration so I could be sure the ignition timing is advanced as much(for this altitude) as reasonable without any knocking.

I didn't have to start buying higher octane premium gas with this higher compression so that's great and someone said they doubt it would ever need premium even if I advanced the timing more because of the low compression of these engines by design, retarding the ignition timing some would always resolve any knocking.

I believe I currently have the ignition at or perhaps a bit more than the factory setting of 10 deg advance.
There is no coolant or oil leak any longer in the pump/timing cover areas. I did use black gasket maker as online recommended on the gaskets and extra in the corners.
Also made sure the crank new o seal was centered on the shaft as some said to do.
-
So I think I am done for now trying to easily and sensibly increase the performance and mpg of my van...

I researched short headers and found the believable info out strongly says the shorties do not give any gain and many are poorly made and soon leak and are noisy and give off too much heat for the engine compartment.

I have no intentions of getting long headers along with the required exhaust system redo and their improvements to performance seem limited in the down low rpm range where I tow. My factory exhaust is dual all the way back although it goes into one cat and one muffler. I've been told it's good there.

Side note:
I did engine temp VHT Chevy orange-redish spray paint my cat shields and riveted military custom affordable stainless steel ebay dog tags with my vehicle's vin number on the cat for theft recovery. Also wrapped with steel cable and clamps from Walmart and added small barb wire in the wrap as well, as pain is always a deterrent of thieves.
At least I sleep better knowing I did what could be reasonably and affordably done.
 
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