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Covalt - 85 D100
https://www.slantsix.org/forum/viewtopic.php?t=56667		 Page 15 of 21
Author:  Rick Covalt [ Sat Dec 12, 2020 1:51 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Obviously I haven't posted to this thread in a while, and I have decided to keep the truck for a while. :D

So I am swapping my cars old race motor into my truck with Doug's new 14T pump gear. It was a relatively mild motor with a good head on it than ran 14.7's in the car only turning 5200. When I pulled my oil pump and looked at the gear it looked like it was showing some where from 5 race seasons. So I ordered a new Howards .473 / 220 @ .050 cam like was in it and pulled everything apart. Funny thing is I had lots of play in the timing chain. So much that I could see it gently touching the cover in places. Soooo! off came the crank gear and on went a new chain and both gears. Only problem is I have almost the same play as before. I new the stuff I took off was only run for the 5 years of racing Slant 6 (Not that much real run time) and knew they should not be that stretched.
So now what do I do. This is a engine that has never been rebuilt / line honed. I pulled the bearings out when I put it in the car and it still had the date coded 1974 bearings in it. I installed new Std. bearings and put it back together.

So do they make a shorter chain? I know they do for some engines, but slant 6??? Any help appreciated. Really trying to get this together soon!!
Author:  slantzilla [ Sat Dec 12, 2020 2:43 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Is it the same chain as a pig block? You can surely get shorter chains for them.
Author:  Rick Covalt [ Sat Dec 12, 2020 2:47 pm ]
Post subject:  Re: Covalt - 85 Race Truck
My research shows no shorter chains?

So if I make something like a chain guide to fit in the bottom of the timing cover to take up some of the slack, what material do I make it out of? I was always amazed at how timing chains could run on a guide / tensioner for 100000 miles. Let me know if you have any other insights.

PS. The timing set I used was a premium PBM brand that came to Ryan from Seymour's stash of stuff. I have ordered another timing set and a spare chain just to see if I get lucky and they made one too short! :D :D
Author:  Rick Covalt [ Sat Dec 12, 2020 2:49 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Quote:
Is it the same chain as a pig block? You can surely get shorter chains for them.
For the silent type chain? I will have to look.
Author:  slantzilla [ Sat Dec 12, 2020 2:54 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Oh, I didn't know it was a stock style chain. I was thinking double roller.
Author:  Charrlie_S [ Sat Dec 12, 2020 4:24 pm ]
Post subject:  Re: Covalt - 85 Race Truck
I don't know if they are any better, but I have a couple NORS, Wolverene "Blue Racer" stock style timing sets, on the shelf.
Author:  Rick Covalt [ Sat Dec 12, 2020 4:30 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Yeah, I don't know Charlie? This set from Seymour would have been fairly old I would guess. I would have thought better quality but maybe not.
Author:  Joshie225 [ Sat Dec 12, 2020 4:50 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Once upon a time I went through this. Tried about 4 different timing sets and just used the tightest one. I mentioned this to Doug Dutra in probably 1996 and he said my block I had simply had the cam and crank too close together. He'd experienced the same thing and his solution was a different block. About the only thing I think you can do within any kind of budget is get a double roller set and shorter chain.
Author:  Rick Covalt [ Sat Dec 12, 2020 5:33 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Yes, I really was trying to get this in and running to test the new gear and stuff. Here is another problem ( I think) with getting the big block set. I am reading a couple places that the difference in the "shorter" timing set is not in the chain. It is in the top gear for the cam. It is made just a smidge larger in diameter to make up that difference. If that is the case then the Big block set would not do me any good since the top gear is different for the slant 6. Again I'm not sure.

At this point I am think a rub block inserted into the timing cover to take up some of the slack is my best short term answer.

Does anyone have any ideas as to what a rub block is made out of in other timing chain guides / tensioners set ups.
Author:  volaredon [ Sat Dec 12, 2020 6:03 pm ]
Post subject:  Re: Covalt - 85 Race Truck
I don't see how you could still have 2:1 if either sprocket was a "smidge bigger"
I have an OLD factory double roller BB Mopar timing set and I recently got an NOS slant 6 cam gear identical to the ones that CharrlieS listed on here for sale a few weeks ago, and while I haven't held them up to each other to compare them yet, I had each of them in my hands within a couple of days of each other and it seems like the slant can gear has a deeper"dish" to it than the BB cam gear.
I know that there was a single bolt and a 3 bolt BB cam gear, mine is a single bolt version
Author:  slantzilla [ Sat Dec 12, 2020 6:09 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Can you make the slides from a Magnum fit?
Author:  Rick Covalt [ Sat Dec 12, 2020 6:19 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Quote:
I don't see how you could still have 2:1 if either sprocket was a "smidge bigger"
As long as the teeth are still 38/19 (2:1) the chain doesn't know if the gear is .002-.005 bigger diameter. We are talking very small differences.

I don't know Dennis. I was thinking if I knew what kind of material to use I could get a solid block of material and cut it down to what I need. Countersink the bolts & fasten to the timing cover. But I need to know what I can use. Still looking.
Author:  DadTruck [ Sat Dec 12, 2020 11:35 pm ]
Post subject:  Re: Covalt - 85 Race Truck
Rick, Cloyes makes OE replacement timing chain tensioners. Some are spring loaded others are hydraulic. Cloyes should have an online catalog with photos, I am thinking you could adapt one to fit.
If Cloyes does not have photos, it would be a bit more cumbersome, but RockAuto has decent part photos, you could page through their online catalogue and maybe find something that would work.
Author:  Rick Covalt [ Sun Dec 13, 2020 5:41 am ]
Post subject:  Re: Covalt - 85 Race Truck
I see Cloyes has a catalog, but not one you can download and look through. It appears to me that you can only do a specific model search.

Again, If I just knew what material, or hardness of plastic....etc to use, I'm sure I can make something to work. I just don't want to use the wrong materials and cause more problems.
Author:  CNC-Dude [ Sun Dec 13, 2020 9:12 am ]
Post subject:  Re: Covalt - 85 Race Truck
Rick, that info regarding material selection and hardness is likely proprietary to the industry and may be a rabbit hole you may never find your way out of. The better and quicker solution would be to find an already existing tensioner and modify/adapt it to work. I have seen many types used by all sorts of engine brands and some material is plastic and some is a hard rubber. Some of the more exotic engine brands use the hard rubber tensioners, while the typical Jap brands seem to use plastic tensioners. Both work well, but the key is to find one that fits within the timing cover. I looked at this briefly when I was designing my 2 pc timing cover, but that was really as far as that went.
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