Club Cobra - Flat tappet cam life

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Quote:

Originally Posted by zrayr

Blame for leaks belongs first to poor workmanship and poor seals/gaskets. I've got over 17,000 miles on a Hi-Po 289 engine using Mobil 1 15W-50 with zero leaks.

Z. Ray

Right. But FE's are a bit more notorious for leaks because of certain aspects of the design. It's not just poor worksmanship.

Right now, I'm fine with conventional oils, and I haven't tried synthetic, but it does sometimes cause leaks that weren't seen with conventional oils. Given my usage, I think I'll leave well enough alone.

Quote:

Originally Posted by 4pipes

I'm thinking of switching from Kendall GT-1 20W50 to the new formulation of Mobil 1 15w50 that has higher levels of ZDDP.
http://www.mobil1.com/USA-English/Mo...t_Engines.aspx
http://www.mobil.com/USA-English/Lub...il1_15W-50.asp

Dave, I previously used Valvoline Racing 20w-50, and my oil pressures were 80 psi and above cold AND at RPMs above 3K warm, and only down to about 50 psi at warm idle. I switched to Rotella 15w-40, and they dropped about 10 psi on each end, which I felt more comfortable with, particularly at cold start-up.

Thanks Rick, it was your previous excellent research on solid flat tappets cams that motivated my change last year.

I will be interested to see what the new formulation of the 5W-40 synthetic will contain zinc wise. 1600PPM currently is a lot of zinc!

I just recently discovered that the synthetic Rotella T is not a true sythetic but rather a 'highly refined' version of crude or mineral oil. The process results in a oil that has the properties of a synthetic and is considered a synthetic in the U.S. (due some legal action by Mobil and others). Classified a Group III synthetic.

Here is a brief description of the three types of synthetic oils base:

- Polyalphaolefin (PAO) = API (American Petroleum Institute) Group IV base oil
- Synthetic esters, etc = API Group V base oils (non-PAO synthetics, including diesters, polyolesters, alklylated napthlenes, alkyklated benzenes, etc.)
- Hydrocracked/Hydroisomerized = API Group III base oils. Chevron, Mobil, and other petrochemical companies developed processes involving catalytic conversion of feed stocks under pressure in the presence of hydrogen into high quality mineral lubricating oil. In 2005 production of GTL (Gas-to-liquid) Group III base stocks began. The best of these perform much like polyalphaolefin. Group III base stocks are considered synthetic motor oil in North America

More information on Group III synthetics:

http://www.chevron.com/products/prod...npra_paper.pdf

An excert:

In addition to the synthetic moniker, customers are also concerned with performance. Modern Group III base oils perform at a level that is significantly higher than “conventional” base oils, both Group I and Group II, and substantially match existing levels of performance in finished lube applications already established by their traditional synthetic counterparts.

Quote:

Originally Posted by clayfoushee

Clay, I'm a work in progress! Now I'm researching Brad Penn 20W50. This is the old green oil that Kendall used to make (they bought the refinery). This is the oil that so many engine builders used to recommend, including mine.

The Brad Penn 20W-50 is a good Group III oils with 1200+ ppm of zinc and will work nicely for a flat tappet motor. I went the rotella route because you can get it at any truck stop or walmart in the country. With the recent reformulation of oils I don't know if the Brad Penn oil has changed, you may want to verify.

Flat tappet valve spring life

I am curious as to how often it is necessary to change valve springs to try and avoid catastrophic failures? With sprint race events of 7000rpm over 15mile races x3 per event and some much easier road miles. So not sustained high rpms!!

My camshaft is flat tappet with 180Ibs seated pressure!

Actually higher rpms are better for cal oiling than easy road miles

Every 4th season of SFOS racing from my experience Ant & that includes letting the rockers off each year.:) BTW I have not forgotten your shifter lever, its still here.

Quote:

Originally Posted by rdorman (Post 616533)

While there are tons of reasons why you can destroy a cam, one of the more recent hot topics has to do with zinc content. Having lost a cam myself while running Mobil 1, I have been thinking of a change. Nothing against Mobil 1... I have used it for years in my other cars with great sucess... but those cars did not have a flat tappet camshaft. My Cobra does.

I have been considering switching to Rotella T synthetic 5W-40 partly because of the zinc content. Plus it is available at darn near every truck stop in the country and at $13 a gallon (Wal-Mart), the value is hard to agrue with. So, I contacted Shell, told them of our issue and asked them for their advise. Here is their response:

"The Rotella T oils, both the conventional 15W-40 and the synthetic 5W-40, are formulated primarily for diesel engines. Although exact additive concentrations are proprietary, the Rotella T oils have a robust anti-wear additive chemistry and contain substantially more zinc than a dedicated gasoline engine oil that must meet the ILSAC GF-4 requirements for concentration of metallic and phosphorous based additives because of their effect on catalytic converters. While we have no data exclusive to flat tappet camshaft designs, we would expect the Rotella T Synthetic 5W-40 to perform well in these engines."

If you care to see what the zinc content of the oil you are using is, a quick search on Google should give you the information you need.

I have also contacted Crane Cams to get their input and will post it here once received.

I've run nothing but Rotella T 15/40W in eveything I own from my 3.5hp Briggs/Stratton garden tiller to my 475hp race car and everything in between for the last 15 or so years....
here's what I've found...
Company car # 1, 250,000 miles, no problems
Company car # 2, 385,000 and counting, no problems
05 Super duty diesel, 25,000 and counting, no problems
65 Mustang fastback, 23,000 and counting hard miles, no problems
18hp riding mower, no problems
race car, 3 race seasons, no problems,475 hp, 7000rpm chip, on track rpms stay between 3500 and 6800 for 20 to 30 minute races...
daughter's Toyota, 90000 miles and counting, no problems
wife's Taurus, 60000 and counting, no problems

Guess I'll keep using the stuff, it works for me...........

David

Flat tappet cam life

Quote:

Originally Posted by Jac Mac (Post 847626)

Every 4th season of SFOS racing from my experience Ant & that includes letting the rockers off each year.:) BTW I have not forgotten your shifter lever, its still here.

Hi Jac Mac,

Thanks that sounds like a good schedule, I turn my engine one complete turn every month for what its worth. I used to loosen rockers, but havent bothered with this engine, maybe its a good preventative measure, I was under the impression modern valve springs are a lot better than the mid 1970's product?

I would like to organise the shift lever, might email you and get your contact number, let me know as I am getting closer to needing it.

Not a problem on the lever--
The TVR donk suffers more damage from corrosion etc than any actual usage, Normally we shut it down/choke it to death on oil each year- basicly squirt oil down the two front barrels while its running @ around 2500 rpm until its showing blue smoke out back, once the smoke shows we kill it & be ready to stall if necessary in top gear, too much oil & they will diesel or in worst case scenario run backwards, you dont want that to happen believe me! It happened to me on my old Boss 302 once- never ever again, I didnt realise how many Fugly noises a motor could make.:o
One broken valve spring & signs of delamination in the cam brgs, along with a stretched timing chain were only problems after five seasons in total on that build- hence my suggestion of four seasons max. Only one outer coil broken ( In two places ), no apparent reason & no other collateral damage so I would suggest that it happened during last race or later. Gotta be lucky sometime.