SV Series Timing Mark Variation

[Robert Kenney]

Tim,
the index Mark on the cam gear is 45 teeth away from the index Mark on the crank. The crank gear has 45 teeth. Looks to be aligned ok but again that does not guarantee valve timing. Just meant per put it together with the marks aligned correctly.

Robert

 

[Michael Mayben]

Ok, now that things are kinda back to normal, let's continue on with the "timing Mark" subject and all it's spinoffs!

Robert has agreed to analyze all this guapo for us, so on Monday I'm sending him a care package with all components needed to make a definitive study regarding camshaft "position".

This will include parts for determining actual rocker arm ratio for both the welded rockers and the boat rockers.

He's also getting a new typical aftermarket cam drive gear set for I-4/sv apps, an r1 gear set from a very early 152, and an r2 gear set from a '74 era 345.

My eyeballs tell me the new 3336s gear set and the r2 gear set are identical. So my suggestion is that all future cam timing work be done using that replacement gear set since that is the only set available new in the current supply chain.

And surprise!!!! The r1 set as a tooth angle exactly opposite from the r2 gear set so that the cam will thrust the opposite direction from later model engines.

However, when I do an overlay of the r1 and the r2 gears, and taking into account the opposing tooth angles, the r2 set appears to be about 1/2 tooth "different" from the r1 set referenced from the woodruff keyway.

Hopefully Robert can define that for us precisely and then make a recommendation on how to "correct" or enhance cam drive gear position during any I-4 or sv engine re-assembly. I've enclosed both woodruff keys for size comparison with off-the-shelf available "offset" keys.

 

[Carl Wiese]

ok, now that things are kinda back to normal, let's continue on with the "timing Mark" subject and all it's spinoffs!

Robert has agreed to analyze all this guapo for us, so on Monday I'm sending him a care package with all components needed to make a definitive study regarding camshaft "position".

This will include parts for determining actual rocker arm ratio for both the welded rockers and the boat rockers.

He's also getting a new typical aftermarket cam drive gear set for I-4/sv apps, an r1 gear set from a very early 152, and an r2 gear set from a '74 era 345.

My eyeballs tell me the new 3336s gear set and the r2 gear set are identical. So my suggestion is that all future cam timing work be done using that replacement gear set since that is the only set available new in the current supply chain.

And surprise!!!! The r1 set as a tooth angle exactly opposite from the r2 gear set so that the cam will thrust the opposite direction from later model engines.

However, when I do an overlay of the r1 and the r2 gears, and taking into account the opposing tooth angles, the r2 set appears to be about 1/2 tooth "different" from the r1 set referenced from the woodruff keyway.

Hopefully Robert can define that for us precisely and then make a recommendation on how to "correct" or enhance cam drive gear position during any I-4 or sv engine re-assembly. I've enclosed both woodruff keys for size comparison with off-the-shelf available "offset" keys.

Mike,

this is pretty much what I found when I compared the set in my 392 and that pulled out of an early 152. I installed them back to back and found the only difference to be the tooth angle. I have a complete write up in my 100 buck truck thread and if you want I can copy and paste it into this thread. It has many pictures too!

 

[Carl Wiese]

Okay I went ahead and did it. Who knows when I would have got around to posting this info, so here it is.

Here is the first post with some bad info!

I pulled the timing gear set out of a 152 parts engine we have. They are in fairly good shape, so I cleaned them up and got to work.

As you can see the back side of the cam gear has the part number cast into it, note the r1 suffix. The crank gear has the part number etched into the front of it, but I couldn't get a good picture.

How I compared is I lined up the timing marks on the r2 set already in the engine. There is enough of the key on the crank that you can slide another crank gear onto the crank and it will catch the key and align itself. So, now you have an engine with two crank gears on it. For the cam gear I aligned it up with it's corresponding timing Mark on the outer crank gear and the keyway in the original cam gear, then used the cam bolt to hold it in place.

Here are some pictures of how things line up. The oddest thing to me, is the teeth on the gears are backwards from each other. I've got all the gears on correctly, but the teeth are backwards. This maybe to prevent you from using an r1 crank or cam gear with an r2 crank or cam gear? Who knows?

Sorry about the fuzzy pics, they were the best out of the set I took. I tired to get some better ones but they ended up fuzzy as well. Once again the r2 set was installed first and are the darker of the 2 gear sets. The r1 set is installed on top of teh r2 set and are the more shiny of the 2 sets.

So, what is the fix for the r2 set, I mean if you didn't have an r1 set to install?

And the second where I clear things up

I've been barking up the wrong tree and leading you all astray!!

Dad got home from his buiness trip and we started talking about timing gears, cam degreeing and what I have been doing all day. We started looking things over and Dad noticed there was no difference in timing between the r1 and r2 sets. I had taken the teeth not lining up as a timing difference, but neglected to notice everything else was lined up.

If you look at my initial post you'll see I got the crank gear to slide on and engage the key in the crank, then I lined up the timing marks and the key way in the cam gear and bolted it on top of the exsisting cam gear. Wah-la the teeth were off and I assumed a timing problem. However as Dad pointed out, it doesn't matter that the teeth are off here is why.

The original r2 set of gears is on with the timing marks lined up. When we put the r1 set on over the r2 the marks and the keyways still lined up with no rotation of either cam or crank. The only difference between the two sets is the bevel of the teeth being oppisite of each other, that would be why the different part numbers. We could take the r2 set off and install the r1 set without having to move the cam or crank to get proper alignment.

 

[Robert Kenney]

Michael,
during all of your digging have you run across any r3 sets?
Would be good to stick one of those in the mix even if it is used.

Rk

 

[Michael Mayben]

Thanks for putting up the stuff carl! I was gonna ask ya if ya still had the pics regarding your findings from a year ago!

Also...another confusing issue, maybe you can explain this based on your experience in dealing with IH parts at books:

as May be seen in the shots, the p/n suffix is all that appears on the actual part for id. And of course, that is a real advantage for identification.

But...the parts lists for the various drive gear applications show service part numbers to carry the "r91" and "r92" suffixs.

Are the "r1" and r2" suffixs to denote oem part, and the "r91" and "r92" suffixs to denote a service part?

Also...I have several "price lists" which were current in the 1981>1985 time frame for all parts from all IH divisions. And neither of the cam drive gear p/ns show in the price list under either variation. And nothing in the supercession data either. I simply can't see those parts going into the "obsolete" column when the motors continued in production up through the mid-80's.

Robert...I've yet to run across an "r3" or "r93" gear set. But Jeff mentioned that he has seen 'em. He might have a set in some of his used stuff, but I failed to sort through those when I visited ihon last month. There were some gears I found inna box though, maybe he can get zaed to dig through 'em and look for the r3 set! Put that boy onna mission and he don't give up if ya tell him a dollar is involved, he'll make an r3 gear set!

Based upon a previous discussion I had about this with Jeff a few years ago, we "thought" the "r3" (or r93?) gears would have appeared maybe around the late '77 time frame for the "next tier" emissions motor apps represented in the '78>'80 Scout II platform. But again, the Scout parts list for that point in time (mt 130 published oct./1980) does not show an r3 or r93 gear set p/n, it does show the r92 set as a service part.

So again...based upon what we know right now Robert...the fact that the aftermarket replacement gear set is all we can currently obtain new when needed, I'd say all our figgerin', bs'n, and calcs should be done with that set as a constant.

Regarding the lack of documentation and anomalies regarding tim's motor build from ***(my edit), I continue to get bits and pieces of similar "issues" trickled in from various sources who have experienced the same or similar. Seems the output of that operation can be a bit "erratic" at times and has been for many years! We got lots of lurkers watching this thread which has stimulated their own concerns!

 

[Carl Wiese]

Mike,

I'll see what I can dig up. I remember the year before last at Binder Bee we included a booklet on decoding IH part numbers, or something along those lines. I'll have to see if I still have a copy or Dad does. You May want to dig through the Binder Bee stuff, as you might have one and not know it. I am fairly sure it was the year Mike roth was chair, so 07.

 

[Michael Mayben]

I've been looking for that booklet that was included in the bee registration package for three days now!!!! I gotta find a copy!

Since I have most (maybe all??) of the bee production archives here now, I've been through every box and file and can't find that booklet, not even my own copy from the bee! I know I put it away for reference purposes but ya know how I am about filing stuff so carefully until I can't find my own shit!

Now you have called me on this...I was too embarrassed to say anything so I just played dumb, not hard for me to do! The bee dude should have anything bee-related! In 20 more years, all this beecrap will be collectible too!

 

[Michael Mayben]

Found it carl!

It was filed with my 2005 Binder Bee registration packet!

Looks to be publication # 1 008 319 r3. Now I need to find the copy of the IH publication index I have and see if that doc is listed!

Lemme review this booklet regarding p/n decode and see what I can see!

On the last page of this item is one of those famous "IH cartoons"...it states "now put me where you can find me"!!!

On the bottom is the statement..."keep this booklet-it has holes punched to fit two rings of a standard size three ring binder."!

 

[Michael Mayben]

This entire part numbering deal is very complicated if you go back into history. But in dealing with what we deal in (for the most part), the numbering system we are most familiar with dates from a corporate changeover begun in 1944.

The "r1" and "c1" numbers denote a single part, that was introduced after the changeover in '44. If that part is always a component of an assembly (such as the cam drive gear set) and is only available as an assembly.

If the part number contains two digits after the "r" or "c" place holder, then the part number indicates an assembly that does not offer individual components.

Any digit in the r or c suffix other than "1" indicates a revision to the part which allows it to "backfit", but the "1" digit part will not fit applications moving forward from that point.

So in the case of the cam drive gear set, we see an individual part number on the cam gear, and the parts list denotes it is marketed only as an "assembly" including the crank gear. And the digit "2" (or the digit "3" that we are also looking for) indicates subsequent "development" of the assembly, in this case the tooth angle was changed to change the thrust direction. But the r92 gears will backfit to earlier applications as a set!

We'll investigate the suitability of making this document available in some form without stepping into any copyright issues with our Scout/light line family!

For those of you who have actual copies of an IH-produced parts list, there is a tremendous amount of information contained in the front of those volumes regarding serial number/vin decode, part number decode, production data decode, etc.

Regarding the part number assigned to the aftermarket cam gear set referenced previously, that number was developed by the original vendor for the aftermarket replacement parts. And that number has been carried forward over the years including additional prefix and suffix to denote the "re-seller" of that part. At this point in time, that gear set is manufactured in the u.s. And is available from several "brand name" sources, but the actual part(s) are only manufactured in the root by a single source.

 

[Robert Kenney]

So according to IH the r91 and r92 are exactly the same. Then why do so many complain of cam timing problems. Carl's findings seem to point that way.

I question if the cam timing issues we hear about are simply a dumb a$$ move on the builders part. Like mixing a gear into a (matched as they are) set that is not native to the mating gear.

The gear sets have a set designator stamped on them for that reason.


Rk

 

[Robert Kenney]

I looked up cam timing when I got home. Only one valve event timing is listed for the sv 304 and 345. Michael only finds one cam grind listed in his books. When you look at that, what others have seen and the fact that IH lists the r92 and r93 timing sets as being direct replacements for the r91, maybe the gear mix up posibility is more likely.

I won't build the fixture but I will tear down the 152 I have and use that as the test insturment. I need to get into it for another deal I want to work on.

When I get the parts mm is sending me I will have a project for this week end.

Robert

 

[Carl Wiese]

so according to IH the r91 and r92 are exactly the same. Then why do so many complain of cam timing problems. Carl's findings seem to point that way.

I question if the cam timing issues we hear about are simply a dumb a$$ move on the builders part. Like mixing a gear into a (matched as they are) set that is not native to the mating gear.

The gear sets have a set designator stamped on them for that reason.


Rk

It could be when the cams are ground, the maker doesn't know IH used timing gear and grinds them to be used with a chain. He would grind in the pattern a slight offset so, when the chain wore in the timing wouldn't be off.

I degreed in the cam when I installed it and it was right were it should be according to the isky specs.

 

[Robert Kenney]

it could be when the cams are ground, the maker doesn't know IH used timing gear and grinds them to be used with a chain. He would grind in the pattern a slight offset so, when the chain wore in the timing wouldn't be off.

I degreed in the cam when I installed it and it was right were it should be according to the isky specs.

That is a good point!!
I have had conversations with the bigger grinders about IH stuff. Like lobe angles to induce rotation, lifter bore clearances etc. Many say "oh they aren't like a Chevy?"

I think that as long you degree the cam you are ok. Did you have to tweek the cam timing or did it fall right on the cam card #?

My r91 ts was replaced with a r92 ts and timed on the cam card from schneider.

I hope to verify the timing sets so we will know and have something to tell people and back it up with data. The builder should still always gdegree the cam but atleast we can

timing chain compensation would be a very small (2 degree) advance ground into the cam. While the problems people have been having have been characteristic on a retarded cam.

Comp cams actually advances the cam grinds 4* because they feel people habitually buy cams that are to big for their application. This is from a conversation I had with one of the bw's at comp.

Robert

 

[Carl Wiese]

I think that as long you degree the cam you are ok. Did you have to tweek the cam timing or did it fall right on the cam card #?

I don't remember, but I know we didn't have to mess with it after we intalled it to the stock IH timing marks. I'll look into my paper work and see if I still have the scratch paper we were using that day. I should also have the isky timing card if you want it.

 

[Robert Kenney]

Carl,
would like to know what the cam specs are and what you think about it eg power band/ low end torque.

We can add it to the "feels like" list so people can see how others like there cam choice.

If you find the card it would be great if you could post a picture.

Thanks,
Robert

 

[Carl Wiese]

carl,
would like to know what the cam specs are and what you think about it eg power band/ low end torque.

We can add it to the "feels like" list so people can see how others like there cam choice.

If you find the card it would be great if you could post a picture.

Thanks,
Robert

Sorry it took so long, but here is the isky timing card that came with my cam.

 

[Robert Kenney]

Thanks carl,
how do you like it? How is the low end compared to the stocker?

 

[Carl Wiese]

thanks carl,
how do you like it? How is the low end compared to the stocker?

Lol, I haven't been able to drive it!! I have been trouble shooting a vacuum/fuel supply problem that I just recently found linked to the gas tank being full of rust and ruining fuel pumps. So I am fixing that and we'll be off and running!! (fingers crossed and the proper animal sacrifice made)

 

[Robert Kenney]

I didn't realize that was your $100.00 truck. I guess I need to pay more attention to the details.
hope the starz are aligned for ya.

Robert