Wtb tce drtc!

[3400-95-Modified]

No need for it to be a PM... The whole thing is public enough already.

DR group buy members,
Yesterday afternoon I picked up the sprockets from black oxide and checked them out to make sure everything was good. I thought it may be best to check with everyone to make sure your shipping address has not changed since it has been so long and one person has already told me their address has changed. My plan is to get them packed this week, mark the boxes and do the shipping labels next weekend. It would be best if everyone could reply with their current address so I can verify that I have the right one. Otherwise, I will return them to the address that was on the package that was shipped to me as I cut and saved all of the labels from the shipments I received.

I apologize for how long this has taken. There were lots of reasons (health, time and money) but they aren't an excuse and I am truly sorry.

If anyone has any questions, please feel free to email them to me.


Thanks for your patience,
Marc
TCEMS

[blckgagt]

No need for it to be a PM... The whole thing is public enough already.

Seems like i never get his emails. Either way I emailed him back letting him know my address. Hope he gets it.

So, judging by his PM, the sprockets were at fault and not the oiling issue?

[3400-95-Modified]

Some more info...

DR Group buy members,
The DR sets will be going out tomorrow but I wanted to go over some things.

I wanted to assure everyone that the sprockets are good to go. Even though I was told by different gear cutters that the sprockets were good, the chain fit still concerned me. The way the chain climbed up on the teeth in Jon's (3400-modified) video was nagging me. It wasn't until it was explained to me the effects of the pitch diameter, chain pitch and that new chains vary from the manufacturer that I really felt confident that everything is as it should be. To ease anyone's mind who may have any concerns, I will do my best to explain how variations in the pitch diameter and chain pitch have on the setup and the amount of chain wear/stretch as it was explained to me.

First off, I did not realize how much new chains could vary but seeing is believing. I made a video ( http://www.youtube.com/watch?v=E20DCrvkgtg ) showing four of the twenty chains that I had here. Don't make fun of my shaky hands... it's one of the side effects of the carbon monoxide poisoning. Of the twenty chains, only two would wrap around a new stock Cloyes sprocket without popping off when you release it. The rest pop off with some of them taking a fair amount of force to hold them in place. As you can see in the video, chain #1 wraps easily and does not walk up on the sprocket while the others do. For repeatability, I marked the sprockets and chains with yellow paint so the same segment was being used for each demonstration.

Although Otto, the gear cutter, had told me this before, I just didn't or couldn't grasp it. I even mentioned it in an earlier update to everyone in the group buy. Anyways, I called him again Friday and he explained, in more detail, about stretch/wear on the chain due to pitch diameter. Once he reexplained it, I calculated the numbers and can see why he said that the pitch diameter could only change the chain length by a small amount. It was one of those ah-ha moments. See numbers below. I had not thought of it that way but it does make sense when you look at the numbers and think of how the roller chain works. As the chain is wrapped around an oversize sprocket, it's being pulled into the bottom of the teeth which will stretch/wear the chain. This continues until the chain is big enough so the rollers ride freely to/on the bottom of the teeth. Once that happens, the only lengthening of the chain should be from normal wear, lack of oil, dirty oil or exceeding the chain's capacity. In all honesty, I have no idea what the capacity of the chain is or how much load is put on it by the drag of the cam but assume it should be fine as they use this chain in the iron head engines. If anything, the FWD cam should create less load due to the roller lifters. However, I do think that running an underdrive (solid aluminum) dampener is a very bad idea and will contribute to premature wear.

Amount pitch diameter is oversize: .002"
Deviation in circumference of pitch diameter: .0063"
Number of teeth on sprocket: 40
Deviation in tooth spacing: .0063 / 40 = .00016"
Number of links in chain: 64
Max amount chain would stretch/wear from PD being off: 64 * .00016 = .01005"

Note: The biggest sprocket out of the batch was .0045" oversize on the pitch which would have made the chain grow by .0226" in total length. Not something I would want but nothing that would kill an engine as it would only effect valve timing by about .55 degrees and have about .27" chain deflection.

These numbers also give an idea as to how close the chain manufacturers have to hold the chains for a good fit. A slight deviation to the minus side in chain pitch, the distance from center to center of rollers, and the chain will not wrap freely around the sprocket as seen in the video. Any variance to the plus side and the chain is sloppy. That's why they shoot for a little on the minus side when making the chains. Makes sense to me now.

Jon's worn chain was about .09" longer per side than a new chain. The would be .180" longer on the total length or .0028" per link. Using the above formula in reverse, the pitch diameter would have to be .035" over size for the sprocket to stretch the chain that much. The TC set would not even fit on the engine with the sprocket being that big. I doubt that the chain could even be wrapped around a sprocket that large. That only leaves the wear being from a lack of oil caused by the oil grooves not being in the back of the sprockets. Of course, on Jon's set, the metal being blue from heat and slight galling on the thrust plate surface were obvious signs that there wasn't enough oil getting out.

I should have caught the lack of grooves before sending the sets out and I do apologize for the inconvenience and problems it has caused.

Anyone who did not send their TC sets back in should really pull them out and add the oil grooves. I know it's inconvenient and a pain in the ass but it really needs to be done.

I hope that explains everything and puts everyone's mind at ease about using the DRs. If you have any questions, please feel free to ask.


Thanks for your patience,
Marc

Items he sent to me that he said he left out of the above update.

I reread that update after sending it and realized that I should have added in there that the new heat treat process took care of the parts that were oversize. I was trying to relay that I believe Otto was correct in repeatedly saying that it was a waste of time and money for the new heat treat. I just wanted to be sure as my reputation was on the line and a failure is very expensive for the users.

Something else that I forgot to add to that email is that there are variations in sections of the chains. That's one of the reasons I marked the chains for the demo. One section of the chain will fit fairly good but when the sprocket is moved to another area it gets harder to push onto the sprocket. Otto said that is common also and the chain will seat itself (wear/stretch in if you prefer to call it that).

There are so many things I feel bad about regarding the DR problem. Leaving out the oiling slots, taking so long to get them back to everyone and constantly questioning Otto's knowledge. His shop is a family business that opened the mid '50s and the only place he has ever worked besides his 4 years in the Army. He is extremely knowledgeable when it comes to gears, sprockets, splines etc. Plus, he's a car guy who understands the application.

[ericjon262]

got my DRTC back today. the chain fits into the links all the way around, and everything seems right.

[MY91GT(Z)]

I wish I could jave afforded on of these

Sent from my SCH-I605 using Tapatalk

[1988GTU]

got mines last week, but havent opened the boxes yet.

[3400-95-Modified]

got my DRTC back today. the chain fits into the links all the way around, and everything seems right.

My old one fit like that as well, It was only when holding chain in one spot and trying to wrap it with only gravity would it walk out.... which may appear to be slight differences in the chains because a stock cloyles setup responds the same way.

I've been emailing Marc back and forth regarding the possible oiling issue and how it may still be somewhat present even with the new grooves cut, mostly because of how the thrust plate is designed as well as how far the installer puts the bearing in relation to the block face. it could prevent oil from reaching the holes in the thrust plate, or sufficient oil at least.

[3400-95-Modified]

This gives you a rough estimate of his concern...

In text.

, I was thinking of things that could restrict oil flow and thought of some things that could be potential problems. Not just with the DRs but any engine having TC wear issues. I have attached a sketch showing where the oil holes are in the thrust plate relative to the cam bearing and journal. As you can see, the holes are mostly covered by the bearing.
I do not have a stock engine open to see where the bearings are installed from the factory but pushing them in .015~.020" below the surface of the block would allow considerably more oil to escape and get to the chain. The other thing I noticed when comparing Sealed Power SBC bearings to Sealed Power 60V6 bearings is the 60V6 front bearing has a groove cut from the oil hole to the front of the block while the SBC bearing does not. This could also be a problem for someone running SBC bearings. I know the performance book says to use them but it was written based on the iron head engine which doesn't use a thrust plate.

I hope to verify some of this tonight since I have both an original 96 3100 to reference and I also have a bare 3400 I'm building for someone that is getting SBC treatment so I can install those bearings and see how they line up.

[Superdave]

I ran the SBC cam bearings in my 3500, no issues. Was using a pre-99 GM timing set.

[3400-95-Modified]

There probably wont be any "issues" per say but they may not last as long as the OEM setup since I did verify that the OEM bearing is set in just a bit from the block surface, also if you or the installer inadvertently set the bearing in from the block face then you corrected any possible issue.

I know the SBC ones don't have a dual hole setup on the front like OEM does so the set I'm putting in tylers engine I drilled a second hole to be like OEM.

[Superdave]

We drilled the 2nd hole in mine too, I can't remember if they were set back at all. I may have pictures but i'd have to look.

[3400-95-Modified]

It's only about .03 set back if that... That's what Marc measured on one of his. I'll have to check mine later I can post some pics after lunch though.

[3400-95-Modified]

Pics of an OEM 3100 setup

you can see how the bearing is not flush with the block as Marc is suggesting to do when using the SBC bearings.

Kinda wish I knew where mine was placed because I need to pull it all apart to verify if I want.

[ericjon262]

Pics of an OEM 3100 setup

you can see how the bearing is not flush with the block as Marc is suggesting to do when using the SBC bearings.

Kinda wish I knew where mine was placed because I need to pull it all apart to verify if I want.

Thanks for doing this, I need to pull mine apart so I can install the revised set and now I have another thing to look for.

[unchained01]

Got my DRTC today has anyone installed theirs ?