[Shiny]

I suspect they don't make them anymore but don't have a clue.

My suggestion:

["QUICK-SILVER"]

Shiny,
I think it was the tripple valve springs and one too many 8,000 rpm shifts that got them. Probably stretched and tried to jump a tooth. They lived several months of daily driving and getting thrashed hard nearly every weekend in towns all over the southeast.

Other than stretch, the stiff back morse hung in there. At least you'ld catch them during refresh. The others didn't last long enough to merit teardown.

Clay

[Shiny]

Clay,



Mike

[ponyakr]

So far, the thinking is that either Paul has a Morse chain source or "connection" that nobody else has, OR he is selling from some stockpile of out-of-production Morse chains.

Is that correct ???

[KARGUY]

How many degrees of timing chain slop is acceptable?

[ponyakr]

Originally Posted by Shiny

I suspect they don't make them anymore but don't have a clue.

My suggestion:

Decided to call. And, just as I suspected, could not talk to a living person. Robot answering system only. Saves companies millions of dollars every year, by not having to pay anybody to answer questions.

[chevymad]

I have a very old NOS Napa Microtest by Cloyes, 3 seperate piece timing set. I no longer have a pontiac v8. Chain is a Morse made in USA and does not bend backwards. Boxes are coming apart and some very light spots of surface rust(probably come off with a soak in oil) Somebody need/want this? PM me so I don't derail this thread further.

[TedRamAirII]

I would prefer a Morse type chain but am more concerned about how to get the cam timing correct. Offset keys readily available? Mr.Gasket 987G I suppose?

[steve25]

In answer to post 65 , in pro stock motors a difference being off just 1.5 degrees in idle Cam timing has be shown to produce a drop off of 5 hp.
This amount can win or loose races in that class!

In a street strip motor that may already be on the edge of producing enough idle vacuum, that same 1.5 degrees or better can make or brake your idle !

[dataway]

Gear Drive!

https://www.jegs.com/i/Edelbrock/350/7895/10002/-1

[Cliff R]

"I would prefer a Morse type chain but am more concerned about how to get the cam timing correct. Offset keys readily available? Mr.Gasket 987G I suppose?"

The Mopar set is NLA. Mr Gasket still has at least one offering and there is another option available that fits a Mercedez Benz engine or something similar, I just can't remember what application at the moment......

[ponyakr]

"...Offset keys readily available? Mr.Gasket 987G I suppose?..."

Yeah, if you have $15+ to spend, there are plenty of 'em out there.

Cliff mentioned some Mopar keys that he has used, which are no longer made.

I used the Mr. G keys back in the old days, when they were a reasonable price.

Seems like a really simply item that somebody could make & sell much cheaper than the Mr. G. In this day of cheap Chinese parts, looks like somebody would do it. Could probably make a few thousand for 25 cents or less, each, then sell 'em for $10 or less, shipped, & mail 'em in a small envelope.

Since so many guys today seem to want their cam EXACTLY in a certain place, looks like these keys could sell good, if they were cheap.

I'm guessing that because of the high price of the keys, lots of guys use it for an excuse to spend a few bucks more & go with a timing set that has the 9 keyways.

[Sun Tuned]

Cliff I was looking the other day for some other stuff and saw some .

Honda application? Was wondering lookin at the pic the dimensions on it but there weren’t any.

[mchell]

Lord........never gave a second thought at using a good double roller timing chain ......been using Comp Billet double rollers without issues for years and years

[HWYSTR455]

So what are the consequences of running any of the chains spoken of on this thread? Has anyone ever experienced a timing set 'fail', as in separate while in use? And I'm not talking about the nylon tooth gears.

As I've mentioned a bunch of times over the years, I rebuild engines in the 100-120k range, regardless of condition. I had one engine that I did a top end rebuild and went somewhere around 230k, and I've never had a timing set separate, or so call 'fail'.

The worse experiences I've suffered is around 2-4 degrees max of variance of timing as noted with a timing light on the balance, and giving it throttle and letting off. That's at 100k miles. I've seen 1-2 degrees at 50k miles, but I've also seen that right at startup of a new build too.


.

[Cliff R]

I wouldn't be afraid of them. I have several stock sets from NAPA in service and one SA Gear set out there still getting it done just fine.

One of those engines has actually logged over 50,000 street miles, it has the set from NAPA in it with the cast iron top sprocket with 3 cut-outs in it. That engine was done back around 2003 and the owner drives it a LOT.......Cliff

[Kenth]

Originally Posted by HWYSTR455

The worse experiences I've suffered is around 2-4 degrees max of variance of timing as noted with a timing light on the balance, and giving it throttle and letting off. That's at 100k miles. I've seen 1-2 degrees at 50k miles, but I've also seen that right at startup of a new build too.

I would like to know how the load on the chain ceases when you let off the throttle?
I have always thought the chain was "loaded" all the time engine was running, it drives the camshaft and valves, not the wheels.

[dataway]

Originally Posted by Kenth

I would like to know how the load on the chain ceases when you let off the throttle?
I have always thought the chain was "loaded" all the time engine was running, it drives the camshaft and valves, not the wheels.

You really notice the slack in the chain when you put it in reverse

But I'd guess with a worn chain between acceleration of engine components and deceleration you could still see some timing changes, centrifugal forces acting on the chain at higher rpms, more stress squeezing oil out of rollers, and between rollers and sprockets when worn. Maybe not an issue of backlash ... but the difference between low stresses and high stresses as rpm changes.

And if you have a 20 lbs distributor rotor that can cause problems too.

Ok ... I'm done with the humor

[Shiny]

Originally Posted by ponyakr

Decided to call. And, just as I suspected, could not talk to a living person. Robot answering system only. Saves companies millions of dollars every year, by not having to pay anybody to answer questions.

ponyakr: Sorry about that outcome. We all can empathize. Was worth a shot I guess.

But back to your quest for BW part number/availability information, I sent them an email asking for info, will let you know if they choose to respond.

I also tried to find the part number of a vintage or modern BW chain by following a similar path as yours on the internet. I think there were several thread contributors making money for search engines on this topic!

I had little luck.

Honestly, I don't know if anyone can verify the currently available stock replacement chains are weaker/cheaper/crappier than a vintage Borg Warner. After reading this thread, I think a lot of experience/opinion is biased by using a stock or aftermarket chain on applications with higher valve-train loads and higher rpm but I'm just speculating.

I did find a page from a 1955 BW catalog on an archived eBay listing that shows 1955 BW part number for Pontiac V8 was TC347 (attached).

There is a NOS BW TC-347 chain on eBay that states 55-58 application so this is not likely the right number for 67+ V8. If anyone is interested in the part, here is a link (not mine):

Link to Vintage NOS BW Timing Chain for 55-58 Pontiac on eBay


If you want to spend $15 just to get the "right" vintage BW part number for 67-79 chains, there is a 1973 BW catalog listed on eBay. Again, not mine but here is the listing:

Link to 1973 BW Catalog on eBay

Maybe the seller would open the book and give you the part number if you asked?

And finally, I stumbled on an eBay listing (Link to Vintage BW Chain on eBay) for a 67-79 Pontiac 400 chain. It was listed as "Double Roller" but clearly was not. Unfortunately, the listing did not include the BW Part Number.

I bought it anyway just to say I had one (I'm a hoarder now!) and will let you know:

a) part number on the box
b) how it compares to the chain included in the Spotts set

[Shiny]

Originally Posted by Kenth

I would like to know how the load on the chain ceases when you let off the throttle?
I have always thought the chain was "loaded" all the time engine was running, it drives the camshaft and valves, not the wheels.

fair warning.. lots of trivial questions and random thoughts coming


Would a worn/stretched timing set ever cause the timing to "bounce" or just to creep?

If it bounces, then it must be about dynamic behavior and/or elongation vs load as Dataway suggests.

I'm curious how much actual load the chain sees vs rpm vs other factors (spring pressure, lift, pump pressure, oil viscosity, etc.). I wonder how much "design margin" chains really have?

For that matter, what does "stretch" really mean? Probably more about wear of the individual contact surfaces and/or load distribution across "shared" contact surfaces (tolerances putting more load on one element than intended) than actually "stretching" of metal parts.

I like the idea of bolting in a tensioner if sensitivity to timing changes of only 1.5 degree cause grief. Is this a commercially available bolt-on?