oil

[rysmee]

i'm nearly finished re-building my engine...
what oil do people recommend for --
1. bedding the engine in? a half decent semi ?
2. and then after 500 or so miles? an expensive fully synth ?
any info will be helpful, thanks.

[mikeoxford]

use GM oil filters if you have rebored? well you should anyway as they catch much finer items. including tiny metal flakes if u have rebored or any work like that

[novax]

Vauxhall recommend semi for most of our engines as they're all getting on a bit. I'm using semi, and will in the new engine as well.

[Dicko]

depends what work youv had done. so wot have u had?

[NovaNeil]

I've always been told to put the cheapest mineral oil you can find in for the first 500-600miles then some semi for another 1000miles. Then whatever you want after that (Either semi or full) But bewarned if you have done over 100,000miles Fully Synthetic might not be the best option, as its too thin.

But everyone has there own opinions on this subject. EG: Courtenay told me to use Running in oil after a full rebuild, but I found there was more out of the engine than in after a couple of 100 miles. :o

As long as you change it at least 2-3 times within 1500-2000miles, you'll be fine I would of thought. Just don't let the oil get too black. :(

[CP]

From what I have read/been told the main practical difference between synthetics and mineral oils relates to:
1. Viscosity and its effects during initial startup from cold and /or operation in cold conditions. The first part of the numberings used to classify oils eg the 15 from 15W40 describes this viscosity characteristic. The lower the number the lower the viscosity ( thinner) under cold conditions. Synthetics are designed to be thinner Hence 0W40 synthetic is very thin and remains highly fluid in cold conditions. The W apparently stands for winter.
2. Synethetics are also supposed to be more resistant to physical degradation under arduous conditions and therefore are generally preferred for higher performing modern engines.

I dont think for most Nova engines it really matters too much whether you go for a good mineral 15W40 or a fully synthetic 0W40 or anyhting in between as regds general engine wear etc. However i reckon fully synthetics are wasted on the majority of Nova engines plus it pisses out of everywhere - its almost impossible to keep in the engine if you rag it about.
I would go for maybe a cheaper branded 10W40 unless you are tuned to fook and change it often - 5000 or less miles. Clean oil is more important to your engine than what sort it is. I use the Halford range which seems fine and is quite a bit cheaper which makes frequent changes less of a burden.

[rysmee]

no i haven't re-bored. i'm using standard pistons with new rings and just honing the bores myself.
everything else in the engine is new or uprated, B+ head, courtenay cam, new lifters, rockers, fully lightend /balanced bottom end, arp bolts etc etc.
yeah i'm just going to speak to bernie at n tech to see what he recommends, but i am prepared to change oil often (maybe as little as every 3000 miles) as i want to keep this engine in top nick. so the oil is very important to me. i have even invested in a digital oil temp gauge as i've read that you should use as little throttle as possible until the oil is up to 50 c.... which leads to my next question.. in the post above.., please help!

[mikeoxford]

if you hjave honed the bores still expect abrasive dust

[CP]

BTW re:honing - a friendly word of caution :!:

I dont know why you are considering doing this but I wouldnt bother if I were u.
If the bores are within acceptable wear limits then there is no point in taking out the rings and changing them unless ones broken and then that will have scored the bore most certainly. They will be fully bedded onto fit the bores and will be helping the engine to give full power. Honing wont help in any way whatsoever.

If however the bores are worn ie more than 1 or 2 thou or so and are losing oil up the sides plus there is visual damage ( scratch/score marks) etc honing will be a waste of time. You need to re- bore.
In my ( relatively limited experience) honing is really for special situations like when large engines have glazed their bores. I have done a couple of Cat diesel engines for this problem which is quite common. I've never heard of it in small high revving car engines tho.

Take your block to an engineer that specialises in car engine re- boring and get him to measure the wear accurately and advise accordingly.
Tuning accelerates internal wear so if in doubt get it re- bored.

[craig green]

When my lump was rebuilt I was advised to change the oil regularly. 3k was the approx intervals given, change of filter every other oil change at these intervals. Thinner oils will result in lower oil pressure when really hot, but if you change regularly cheaper oils are perfectly acceptable. For the 1.4 & 1.6 engines, apparently they could do with bigger sumps really. Its because of this that the bottom end can suffer carbon build up around the crank journals (as mine did) because the oil gets used a bit harder. My engine builder fits multiple sump gaskets so to increase the capacity in the sump. About 4 when running in then 2 when U can be bothered to change em. GM filters too!

[Dicko]

to be honest i can never see why people say this 'change of filter every other oil change at these intervals'

its a load of pap. for ?3.50 go and bloody buy a new oil filter while your changing the oil!!

[wisewood]

Dicko has a good point, its only takes about 60 seconds to do it.

[craig green]

Its what ever you feel works for you isnt it? What this tries to demonstrate is that the oil can be replaced often enough that changing the filter wont make much odds when its clean(ish) oil coming out. Personally I change mine at 4k intervals using fully synth VAG oil & GM filters. I always pour a litre through when the sump plug is off to flush the sump through.