Here's a video of the timing chain slack on the 70 455 I'm building. I currently have it stripped down to the bare block and doing the oil mods but I took this video awhile back. Is the amount of play in the chain normal and can be reused or is it worn and should I replace the gear and chain?
If there are no noteworthy wear marks in the teeth of the gears just get a new chain. If there are wear marks get a new timing chain set. Don't go anywhere near a billet timing set unless you plan on degreeing in the cam.
The billet timing set is that the one with the 9 keyways? I was going to try and get the cam as close as possible so decreeing it would be necessary right? I've read on here that just putting the cam in isn't the proper way to do it and it will have negative effects on the performance of the engine and leave behind some HP.
Yes it is. I just mentioned the billet set because some people decide they have to get the billet set without realizing there are too many variables with it and you all but have to degree the cam when using it. How big of a build is this and what cam are you using? IMO a smaller cam being off a few degrees will make less of a difference to performance compared to a bigger cam. If you can get a cam degreed in then it is worth doing but not absolute for a mild build. Going back to your original post asking if the chain is too loose. If you ask that question I would assume it is a stock or mild rebuild.
It was a rebuild done 25 years ago but never ran, it sat in a guys shop so I'm tearing it down and rebuilding it as it looks like it was a quick cheap rebuild. My plans are to build a mild street/cruiser engine but still have the power for playing at the track when needed. that being said I am going to do a few things better so I can just "add on" at a later date. I will probably use autotec customizable pistons & molly rings to get to 0 deck, 68 430 iron heads (TA Aluminums later on) with fresh valves and maybe a bit of home port work and bowl blending/polishing not sure on a cam yet but Larry the Wizard mentioned a cam in another post from TA that is 113 la or something and when I read the specs on it it sounds like what I'm after. I have a performer intake, 72 Qjet from everyday performance and ta shorty headers along with other bits and pieces I'll use from my current engine. I would like to get close to 10:1 compression, close 500hp and stay with running 91-93 octane. I have dual 2.5" exhaust also.
During the rebuild it was probably line honed thereby causing the chain to loosen further. Undersized timing sets are available for this reason.Your current set will loosen more after you put some miles on the car. If you are concerned about the current timing set get an undersized one,they make them in varying sizes, .003",.005", .007". cost is about $125-150.
I don't think it was I think new pistons and rings were put in along bring bored .030 and with a stage 1 cam brand new from the GM dealer and maybe some gaskets. The cam bearings were scored up a bit but the new cam was never ran so that leads me to believe he was just slapping the bare minimum in there to get it running again. The crank and rod bearings all looked good but I'm doing all new bearings. The timing chain set that was in there was a replacement at one point since it's all metal teeth no nylon tips.
Check the timing gears. If there is even minimal timing chain wear marks in the gear set then it was used for something at one time and that could account for the stretch. You should be able to tell just by looking at the main bearing saddles if it was line honed or machined at one time. As Gary said you want to compensate for that if it was done. Take a picture if you can of one of the saddles. The TA C113 is a good all around cam. Basically a copy of the old KBC113. Enough overlap to let you know there is a cam in it and with that build I would get it degreed in. You'll definitely want some gears and a higher stall converter if you go with that cam. If you try to use the factory 13" from that Riv it will be a dog until it hits 3000+ rpm. Great from a roll but not from a dig. Not to mention it will be a bit rough at idle in gear. If you have the typical 27cc forged pistons in that engine and 66cc heads you won't need to have a "0" deck to get close to 10:1 which is about the most you want to go with iron heads and 93 oct. pump gas. 9.5 would probably be better with a heavy car. If you plan on aluminum heads down the road maybe go for something around .013" in the hole and then run the Cometic 027" head gaskets with the AL heads. That will get you around 10.2 which should be fine with AL heads. Use .040" head gaskets with the iron heads and you will get 9.92 which is getting pretty exciting. You probably wouldn't be able to use maximum best timing in a heavy car especially on hot days. Maybe the heads are not 66cc or you can get the thicker Cometic head gaskets. The AL heads may actually be down around 62 cc. You are going to need some real CC numbers so you can do some real calculations. Especially because you plan on getting TA heads and unless you are doing the headwork spend as little money on the iron heads as possible. If there is good margin on the valves no need for new ones. Just have a nice 3 angle valve job done and have them back-cut. Clean up the area under the valves if you are doing it before the valve job. No porting is necessary. The bottleneck is under the valve. You couldn't clean it up enough under there to warrant porting or port matching the intake or exhaust ports. Maybe a minor .010" cleanup surfacing if needed. You do not want to lower the CC of the chamber much if at all. Obviously you need valve springs to match the upgraded cam.
I will take a look at the gears and chain for wear tomorrow and report back. It's safe to say it's in my best interest to just replace them. I haven't had the bearings pressed out yet so I won't be able to see the saddles if they've been honed or not. I was given a link on another thread for a poston GS-113 cam and it sounds like a nice cam! I have a b&m holshot converter that is 2400-2600 stall I think and a 3.08 posi rearend. I have a set of .040 head gaskets in the package ready to use and when I eventually go to AL I'll do the .020 steel shim gaskets. I have to check the cc of the pistons and if they're 27cc I may reuse them with new molly rings. What cc's are the 68 430 heads??
I will probably have the block machines a bit just to clean it up that should get me closer and maybe have the heads milled a bit yo drop the cc's
Its a good idea to mill the block and heads a minimum amount to be sure they are flat, especially if using a ,020" shim gasket. If you mill excessively the intake bolts won't line up and you'll need to mill the intake side of the head too. The 113 is a nice sounding cam, but as Mike stated a higher stall converter is required, also, the 113 will be marginal for vacuum for brakes and a vacuum can may be needed. If pistons are not notched piston to valve clearance must be cheked as it will be close due to overlap, the 118 is ok. Any cam should be checked for p/v clearance if the piston isn't notched.The 118 is the same specs as the 113 other than the LC and has plenty of vacuum. Sandy's X has the 118,runs 12's, my friend opted for the 113,runs 12s, and needs a can.Use TA dual grooved cam bearings. You should also open up the main oil feed from 1/2" to at least 9/16 or 5/8 if you are going to spin it past 4500rpm, and thats what you'll do with a cam change and more converter. Also a white spring in the oil pump, possibly a booster plate if the pump cover is worn.Its all combination, and building for reliability.
Greatscat thank you for the tips! I've been doing the oil mods suggested by Jim is his oil mod thread and definitely will use the dual groove bearings. I've been holding out on buying a cam as I want to make sure I get one that meets all my requirements. So far the 113 is really close to what I'm after but the break vacuum is an issue as I don't want to add a canister.
Glad to hear, oiling is an issue with any performance build. TA has several cams that sound good and have vacuum or you can have Scotty Brown custom grind one for you,same cost as TA cams. I've had probably 10 done and was never disappointed. I love the 118 though, old school but lots of power, some lope and vacuum. Booster plate is a good investment.
Yes I like the specs on 118 also. I'm going to get most of the parts/build going first then see what cam will realistically be best suited for the parts I selected/can afford. I have a booster plate and adj. Pressure regulator on a proform cover that is currently on my engine in the car now that I'll reuse with a pump rebuild kit if funds do not permit a fully setup TA cover. As for having scott grind one, do I just tell him what I'm after and he picks some numbers for me and makes it? I assume he'll need all the engine specs to get the numbers right?
The proform cover has worked well on a lot of motors we've built, unless there are issues why replace it. Yes, Scott would need all specs on engine and car plus desired results.He will then design it. Sometimes it takes a month to get it so if in a hurry get one off the shelf.
Yep as far as I can tell mine is working good. I'm not rushing this motor build as my 72 455 that's in the car is still running strong, it's just not built to the way I want it. I put the 70 build on a minor pause as I have to rebuild my th400 due to severe leaks and unfriendly noises lol. I will still continue to collect parts for it in the mean time. My wife and kids just bought me a full trans kit with red alto plates, kolene steels etc. I will pick up a 34 element sprag and a transgo 1-2 kit. I would like to just reuse my b&m converter but from what you and others have said about my build plan I may need to go to a bigger stall.
So I checked for wear on the gears and the teeth are rounded on the corners on both gears and there's a "1978" stamping in the main/cam gear so yeh I'd say its time for a new set
