1968 Tappets, Rollercams & Zinc Additives

[daveS]

Hey all,

So I am doing some shopping and research about getting my J code GT/CS motor rebuilt. I've talked to a few shops, but one in particular is trying to sway me towards roller cams instead of the original tapped based top end. They are claiming that with the new oils available today, there is not enough zinc in them to help prevent wear on the high pressure area of the cam/tappet interface (makes sense I suppose). When I got my car tuned there, they added some zinc to the oil to help out with this. The thing is, a roller cam rebuild is much more expensive than the original tappet based rebuilt...but the claim is that the roller cams will last much longer and not need the oil additive.

Any thoughts on roller cams vs tappets ? .... and zinc oil additives ?

Cheers

 

[franklinair]

I rebuild my engines to stock configuration. Probably put 700 miles a year on my C/S. For the cost involved (unless you're looking for a high performance engine) I stay with stock everything. Even if you opt to put in oil additives, that's a lot less expensive than roller rockers, etc.
I guess it depends on what you're looking for, in performance. My stock 302 4BBL & Pertronix ignition does the job for me. Any concerns (if any) regarding lubrication can be handled with additives.

Neil

 

[daveS]

By the way...as I talk to more shops about rebuilding the engine, for stock rebuilt I am getting quotes for $2500-$4000....for roller cam rebuild I got a quote of about $6000. This is for a complete rebuild where I drop the car and keys off, and get it back turn key. Seems like both are expensive but I am seeing a rollercam rebuild is much more...maybe even twice the price. I'd really prefer to keep the car a stock as possible but the rollercams are transparent to appearance.

 

[tomcwarren]

I agree w/Neil. You've got a J-code - pretty rare to start with. Keep it stock - it'll do just fine w/leaded gas (w/hardened valve seats, etc.) and oil additives. Here's a link to a great site w/info on ZDDP oils:

http://www.enginebuildermag.com/Article/3100/performance_oils_and_additives_got_zinc.aspx

HTH,

Tom

 

[Midnight Special]

By the way...as I talk to more shops about rebuilding the engine, for stock rebuilt I am getting quotes for $2500-$4000....f.

...Not bad at all for "turn key". Stock is just fine and despite all the ZDDP fears, no so called experts have proven conclusively IMO that it's a real problem. There were some defective camshafts where the oils were blamed, but unless you're racing at 6-8K rpm, I'm told not to worry.

Neil may know, but I believe this originated with high-performance airplane engines having cam issues with articles written about the "theory".

I do pretty much the allowed 3,500 miles per year per car (289, 302, 351C, 390 and 428...for the better part of four years now (and I don't "baby" them) ...Never had a camshaft problem...

 

[teamlo]

Coincidence, my cousin and a buddy of his just completed a rebuild of a
J-code 302 for my '68 GT Coupe. Ended up going with a Comp Cams flat tappet hydraulic cam similar to the 289/271 HP grind. 9.5:1 compression, stock cast iron 4V intake, stock exhaust manifolds and factory style 2" dual exhaust, Autolite 4300 4V carb, stock distributor with Pertronix Ignitor, heads basically stock with hardened seats and upgraded valve stem seals. The engine was fully balanced prior to assembly. I am flying to Maryland in 2 weeks to pick it up and drive it home to New England. I'm told the engine has a great powerband and is very responsive. The car has a C4 automatic and factory 3.25 open rear. I believe they used Valvoline Racing Oil with the higher zinc content.

Best of luck,

Terry

 

[murf104]

Either you misunderstood or the shop that mentioned lack of ZDDP in the gasoline is a bit confused. I think you will find that the ZDDP anti wear additive is in the oil, not in the gasoline, no matter what State you inhabit. I feel that if you use good assembly lube when doing the rebuild along with a non synthetic oil with at least 1200 PPM of ZDDP for the first couple of thousand miles in conjunction with Ford specified valve spring pressures you will not have an issue. There are still lots of different brands of oil that have the needed level of ZDDP for use with a flat tappet cam. The net is full of information about this, and a call to the tech department of any major oil company will get you valid and current information as to the ADDP level in their oils. Most people who rebuild their engines have no trouble with abnormal cam wear, and although the level of ZDDP has been reduced I suspect that other issues may have contributed to the reported "epidemic" of cam failures. I think it is on the same order as the much discussed but never arrived epidemic of the bird flu that we were promised a few years ago.

 

[Mosesatm]

Either you misunderstood or the shop that mentioned lack of ZDDP in the gasoline is a bit confused. I think you will find that the ZDDP anti wear additive is in the oil, not in the gasoline, no matter what State you inhabit. I feel that if you use good assembly lube when doing the rebuild along with a non synthetic oil with at least 1200 PPM of ZDDP for the first couple of thousand miles in conjunction with Ford specified valve spring pressures you will not have an issue. There are still lots of different brands of oil that have the needed level of ZDDP for use with a flat tappet cam. The net is full of information about this, and a call to the tech department of any major oil company will get you valid and current information as to the ADDP level in their oils. Most people who rebuild their engines have no trouble with abnormal cam wear, and although the level of ZDDP has been reduced I suspect that other issues may have contributed to the reported "epidemic" of cam failures. I think it is on the same order as the much discussed but never arrived epidemic of the bird flu that we were promised a few years ago.

Awww, Murf beat me to it!

It doesn't matter how much zinc is in the gas because it isn't going to help your lifters. If you have gas on your lifters you'd better pull over....quickly!

He hit the nail squarely on the head on the other issues, too. Assembly lube, then run a high ZDDP oil for the first thousand miles, after that run whatever oil you want, as long as you change it often.

Unless you have super-strong valve springs you shouldn't be wearing out cam lobes, and as long as you're not planning on taking the engine over 6000rpm you don't need super-strong valve springs.

My recent complete engine rebuild and dyno testing was right around $3,000 with me taking it to the shop and picking it up. Add a least another $1,000 if the shop removes and reinstalls the engine.

 

[franklinair]

Not knowing where daveS lives (big town/small town), I can only relate my own experience. If you know of a good engine rebuilder locally, then I would choose that course- assuming you can R&R the engine and accessories yourself. In all likelyhood the cylinders will probably need to be bored.I like to keep that at a minimum, but no more than .030". I would guesstimate that a good, stock o'haul would run about $1,000+/-.
One of the advantages of pulling the engine yourself is having the time to clean & detail the engine compartment & accessories.
What's your position re: doing the R&R, and the cleaning/detailing type work?

Neil

 

[daveS]

Either you misunderstood or the shop that mentioned lack of ZDDP in the gasoline is a bit confused. I think you will find that the ZDDP anti wear additive is in the oil, not in the gasoline, no matter what State you inhabit........

Awww, Murf beat me to it!

It doesn't matter how much zinc is in the gas because it isn't going to help your lifters. If you have gas on your lifters you'd better pull over....quickly!
.......

Oops ! Sorry, guys....Yes I absolutely meant to say "oil" instead of "gasoline" in my original post. I went back and corrected my original post. Thanks for posting !

-Dave

 

[Midnight Special]

...I think we knew that... Did you talk to Mike in Chico?

 

[daveS]

...I think we knew that... Did you talk to Mike in Chico?

Hey Tim...I called the place in Chico. Mike has was out for the week but I talked to another guy. He quoted me about $2500. I just have to get the car up there from San Jose and drop it off when I can find the time. I'll probably call them back and talk to Mike himself a little bit about what I want....just a basic rebuild, all stock. From what I have gathered, sometimes prices float around a little during the rebuild process depending on how much of the bolt on stuff can be reused on the rebuild. Thanks a ton for the referral, much appreciated.
-Dave

 

[Mosesatm]

My engine guy is rebuilding another engine for me and when I asked him about what oil to use he told me in no uncertain terms to run Valvoline VR1 Racing Oil and nothing else because he knows from personal experience that new oils can wipe out a cam in the first 20 minutes of running the engine.

He builds race engines and works on little J-codes only when he has time so his experiences with cam failures may not apply to regular engines, but I'm going to take his advice just to be safe.

Either regular http://www.valvoline.com/products/consumer-products/motor-oil/racing-motor-oil/6/
or synthetic http://www.valvoline.com/products/consumer-products/motor-oil/racing-motor-oil/8

 

[Mosesatm]

Edelbrock now has high zinc content oil.
http://store.edelbrock.com/lubricants.aspx