Well, since I needed a cam anyhow, thought it was a good idea to mildly improve it rather than put a stock one back in. Russ Martin reccomended his "425" cam and estimated a 4 degree offset keyway would work if I was keeping the stock timing gear set up. "Degree it in to be safe", so we did and found it needs another 4-6 degrees, and the new link chain with melling steeel gears is sloppy to boot. Anyhow, builder reccomends a timing chain set that can be adjusted for this cam, of course Russ has one for $190 plus shipping........but I gotta stop this bleeding somewhere. Does anyone have a more cost effective alternative or solution? Or any experience based advice on how to NOT waste anymore money on this nailhead?
What installed ICL is Russ recommending, and what is the ICL of the cam itself? Advancing or retarding a cam 8-10 degrees is quite a bit, so I'm just curious what you've got and what your after.
The shop doing the block work is assembling the shortblock. What I have is a +.030" '66 401, new pistons/rings, new stock bearings throughout, freshened heads needed little, and the cam measured wear on two lobes. So RM suggested this slightly better than stock cam which he called a "425 Cam" and is supposedly the first level of camming beyond stock. I explained this was no race motor and most everything else would be stock, specifically the timing gear set and chain would be a Melling stock replacement set (metal gears). RM explained this cam normally required a 4 degree offset key to get the gear marks to line up and sent one with the cam/lifter set. The assembler was degree-ing in the cam and found the new link belt chain was very sloppy, he was at roughly 106 but felt it needed to be more like 110-111. The replacement timing gear set up does not allow for that adjustment. Soooo, after being frustrated with the endlessly increasing cost of this rebuild, I thought to ask the community about options rather than just shelling out another $200 to buy RMs timing gear set. Thats what I got. I apologize for sounding crass and do realize you are all (mostly) trying to help me, but this Nailhead has cost me three times what was planned on and I am just plain torqued at myself. The Nailhead Novelty has worn off!
If you can find them, small-block Chrysler offset cam keys fit the nailhead. Here's a Summit racing link that shows them as being discontinued: http://www.summitracing.com/parts/dcc-4286500 Maybe you can find them elsewhere. I'm sure Russ knows this tip. You generally can't move the cam much from the 'centered' position as valve-piston clearance becomes a problem. As for the sloppy chain, maybe a different manufactures' chain will fit tighter.
Thank you all, I appreciate the knowledge. It looks like TA offers a stock style link chain with a 9-key crank sprocket for roughly $100 delivered or the single roller for $200. Anyone have experience with either of these? Good, Bad, or Indifferent? Any feedback is better than none!
all the chains will be loose unless you go with the single roller which will stay tighter too.whats the lsa to start with. can you post your cam card. don't understand why you should need the the first 4* to start with.
Was that 106* with RM's supplied 4* key? If so, then 110* would use standard key, or if 106* is with a std. key then turn RM's 4* key the other way. Sounds like you have what you need already. Unless I'm understanding this incorrectly... I'm curious why your builder doesn't want the cam @ 106*. If he/she is giving a generalized assumption as to the compatibility with pump gas there's a lot the builder can do to influence that without spending your $$ to move the cam. If that is the reason (and not valve relief), then they should knock down all sharp edges anywhere in the combustion chamber and piston to negate such effect, for no extra charge, of course...:grin:. Also wider exh. valve seats go a long ways towards preventing det. What solutions did your builder offer?
did that builder line bore the main saddles ??? if so, then that is the source of the sloppiness in the timing chain..... I never ever do that.... it creates slop in the chain that you have almost no way of getting out except a idler and that is expensive... go with a stock , all steel t/c and gears and install it straight up.... Buick already ground the advance into the cam...4 deg.:Brow:
All good questions, I will inquire and report back with some facts. I have requested the CAM card info from the builder and he told me yesterday he has spoken to RM directly. Would I be correct thinking a line bored block would require modified main bearings and/or cam bearings? I am relatively ignorant to the detailed inner working relationships of ICE cams. That is why I am relying on the builder to assemble the short block. Locally, this builder is well known in circle track, strip, and restoration work for 35+ years and has done several more obscure than SBC motor builds for car club guys around here. The shop is called Speed Performance Research out of Port Washington, WI. Lets see how this goes, I am so far into it there is no choice but complete the project.
Line boring moves the crank closer to the cam.... and that puts slack in the chain that you cant get out....:Brow:
line bored do not require modified bearings, but like doc said it makes your timing chain have more slack.
425 cam CAM Card Here is the cam card. Well, tried about five times but the file fails to upload in jpg format. It is the TA112 cam from TA Performance, the diagram lists "For degreeing cam at .050 tappet rise", ".301 lift ex, .290 lift in, 215 ex duration, 210 in duration, 0.0 overlap, degree intake lobe to 106 for 4 advance" Assembler noted he could only get 103 and chain was very sloppy, he wanted more like 110 or 111. Cam card notes lifter ratio at 1.6/.464 intake/.481 exhaust, but I have been told ratio is more like 1.55. Bit the bullet and ordered a roller timing chain set from RM, another $200 thrown down the Nailhead money pit!
Re: 425 cam CAM Card Was the 103* ICL with Russ' 4* key? And if so, advanced or retarded? I suspect you could have gotten to the 106* ICL without the roller timing chain, although it's not a bad upgrade. Advancing the cam (106* ICL) will give you a little more low end power, at the expense of high rpm performance. Based on what you described your combo to be, I'd advocate this to your builder, instead of letting him install it at 110*.
No harm in installing @ 103* nor 101*. Unless you think getting better mileage or throttle response is a problem...you are going to run out of head and cam before the CL becomes an arguable issue. Not sure why your builder has a problem with this, refer to my previous question. Install it and send back Russ's timing kit. Bottom line is that your builder may have line bored a block in a way that shortened the crank/cam centerline without a way to fix it and now you are on the internet looking for cheap solutions. Why is 106* a problem and getting to 110* an issue that you have to correct around the machine shop? If you believe his opinion then have him get it to that point at his cost and you can live with the result. This is a very mild build that should go together without so much anguish. BTW, you have a cool car and I'd like to see it on the road...
TA has shorter timing chains for align honed 455 mains as that is standard procedure for installing mainstuds and girdles. We used one in our girdled 462 and it was just the ticket. They may have one for the Nailhead or know where to get one. It looks like Summit still carries Mr Gasket offset woodruff keys in 2* and 4* offsets for the crankshaft here. Cheryl
I used a chevy one on my nail head one time. or a v6 buick one from ta. I think are the same. a lose chain would retard it. not sure way its coming it at 103 does not make sense. that's a small cam you have less advance would not hurt it at all.
Ford 429/460 1968-87 uses the same timing chain as the Nailhead, Cloyes pn 493. Sprockets are different. Cloyes does make a shorter chain, but it's a double roller. No idea if it'll work with the roller chain sprockets from Russ. A call to tech support at Cloyes may be your best bet if your chain is real loose. Edit: the shorter chains are for the Ford 429/460. Might be worth checking other manufactures to see if there's a short 429/460 chain that will fit a Nailhead. Edit #2.... never mind, Jim W says the 'tight' sets use different gears, not shorter chains.
Thanx everyone for all the input. I am learning a lot here and sometimes the frustration of what makes sense vs. what I am told vs. my lack of knowledge does get me overloaded. I don't mean to whine so much! :ball: Anyhow, FYI-I have pointed my builder to this web site and RM several times in addition to supplying a copy of the factory service manual. He did tell me he spoke directly to RM after the initial degreeing of the cam. Still do not have a clear understanding of why the link belt chain that came off, and the new link belt chain, were so loose. (left to right movement of 1/2") The Melling steel gears did not show any clear wear. (Thanx for the earlier line boring explanations) As this comes together, I will keep the community up to date and send this Thread's link to my builder. He has been advised along the way that you guys have been watching. Best regards......!
