Actually by changing out all lube oils prior to a race is beneficial in HP. Thelighter weight oils allow the engine to turn faster because its not having to pump a heavy lube oil. The NASCAR boys all use a light weight oil to qualify because it gives them that little bit of extra HP, but they will switch to a heavy oil for the race for longer lasting lubrication.

 

As long as you don't drop below 10 lbs. at idle you will be just fine. I have 5-20 synthetic in my Mach, but am still running 10-40 Rotella in my 65. I'm afraid the old gaskets on the engine will leak like a sieve with synthetic. I am running syntetic in the tranny and rear though.

 

Interesting, I changed from dino to full synth in a 428 Cobra Jet. After about 3 or 4 months I noticed some seepage around the gaskets. I mentioned this to a friend (fellow car buff) and he said that "Amsoil" had an additive that prevented this (via the reps comment). Thus far, I have seen an increase in oil pressure when switching from dino to full synth of the same weight.

 

Yeah, there's no doubt that the synthetic oils such as Amsoil or Redline are far superior to dino oils, but my old 65 has 130K miles on the original engine and she doesn't burn a drop between changes. I'm not doubting, just wondering what that magic additive Amsoil is adding to prevent the old gaskets from leaking. Others I have talked to who made the switch from dino to syn had horror stories about oil all over the bellies of their stangs, but after a few weeks, the gaskets sealed, and not more leaking. Maybe that is what the mystery oil in Amsoil does.

 

I don't know, just info a friend told me he had learned from a rep, this must be ancommon issue with synthetics. Ihad more of a seepage issue that a leak, but that was with Mobil One, not Amsoil. As far as an additive, I dunna.

 

Some info I came across,
"The only real downside to synthetic oils is the cost. It is typically two or three times the cost of conventional oil for a good synthetic. Another little-known downside is that switching to a synthetic oil on an old engine can result in oil leaks. Why? Because the detergents in the synthetic oils will "clean-up" the varnish and sludge left by conventional oils. If your engine seals are worn, the synthetic will break down the oil varnish that may be maintaining the seal. So it's not that the synthetic oil caused a leak, it just that it revealed worn seals by cleaning the varnish off of them. Many people have switched to synthetic on 100,000+ mile engines with no leaks, so it just depends on how often you changed your oil and the overall condition of your engine".
In this situation, Amsoil has an oil "XL7500"that shouldbe used.Theysay it has less detergants so as not to eat thru the crap and crud in an old engine, thus causing a leak.Not an additive per say as my friend has told me, but infact, a lack of.And after reading this info, I think maybe Amsoil has aheads up on this.

 

i did a syn com,parison based off data collected from each manufacturer and came to the conclusion that redline is the "best" oil available followed by mobil 1.

i use pennzoil just because i always have - pretty much any name brand oil isnt gonna kill your motor but everyone has their favorites.

 

Hey guys,

On the subject of oil pressure, conventional wisdom seems to offer, if you have about 10 lbs/1000 RPM you should be in good shape. As I have a 64 1/2 vert, I installed a set of mechanical gauges on the left front fender well near the washer bag. The hard-tube for tthe oil pressure gauge runs down into an adapter off the oil pressure switch. I don't like to rely on the pressure switch alone.
Anyway, regaring oils, I'm switching to the shell rotella (for diesels)as it has more of the anti-wear additives (namely ZDDP) a zinc compound, than present in most of the petroleum based oils today. It seems, when the detroit guysinvented the cataliticconverter, the higher concentration of zinc additives was destroying the converters. So the answer was to reduce the levels. However, zinc beinga major anti-wear agent......,well, I think you see where this is going!
Many of you may know, this problem is really highlighted, when you install a flat tappet cam, whether it be solid or hydraulic. Rollers are less forgiven, as you don't have the same "break-in"regiment.
Hope thisadds to the mix.

 

Good point "kenash". And "Soaring" the guys that switched to synthetic, did all of them switch to"Amsoil" or other brands? I'm about half dino and half synthetic in my cars now, but think nowIwill go all synthetic. Not to say I've had any problems out of dino, but then I do service every 3k.

 

I did a survey a few years ago on another forum, and it turned out that most guys who use synthetic oil use Mobil 1. Mainly because of the availability and price. So, the ones with whom I have had conversations and complained about leaking were mostly using Mobil 1. I like the idea that Amsoil has taken out an additive that cuts out the varnish, etc. I may just try a load of Amsoil to see how the old girl fares. I can always steam clean her if she leaks.