Fiona's New N15...

2500 Miles with nothing above 3500 will not run the engine in properly at all.

You need to gradually increase the load and revs etc over a 1k mile period otherwise the rings won't bed properly.

What you are suggesting runs serious risk of not creating enough friction to bed them in properly and then glazing the bores once you set the revs free...
 
rings bed in within the first 15 mins of use....

even with the engine rebuild your plan for running it in will ruin the engine before you even get started...
 
A ran in mine within 40 miles. 2500 miles is plain stupid....and would take me about 3 yrs!

If you think how fast an engine turns over, all you need the run-in to do is remove any high spots on the bearings. They`ll soon go.
The rings are best run-in using high gear, high load. This can be done in about 10 X 30-70mph runs.

The most important thing is to use a mineral oil to start with, then change it after the above to a semi, then change to a fully syn after about another 20 miles.
 
I would run it in on semi-synthetic for a few hundred miles, then refresh it with the same again. At the next oil change, then put fully-synthetic in if you intend to race/drag/hammer it regularly. I'm basing this on 2 things - a very respected racing engine builder's own practice & my own experience. I once tried to run a brand new high performance engine in which had fully synth in from the factory - it used shitloads of top-up oil & didn't run in properly. Said tuner told me to drop the oil, stick in semi-synth & give it the beans in gradual stages. This I did & within a few hundred miles, it ran in sweetly & made higher figures than the factory had suggested :)
 
Sam said:
rings bed in within the first 15 mins of use....
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Using the method I describe saw my compression tests go up steadily, especially on leak down tests, up to about 800 miles when I started going good boost / high load.

I can see the argument for ragging an engine senseless from the get go and for a methodical breaking in. TBH Both ways seem to work with quicker methods seeming to be better for high compression builds (and bikes).

Either way, what you suggest with 2.5k of low revs is absolutely pointless.
 
Mate yu need to be abit light hearted. no-one has put a gun to your head and said do it my way..

Just abit of advice and experience being handed out, you don't have to take it, thats your choice...

Spend your money how you want, do as you please!
 
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TheStigP11GT said:
there seems to be bits of grit and debris in there, that is going to fuck something up, and i don't want to go down the route of doing a quick fix on it.

last compression test shows all cyls are not even, i will try and dig out the results.

Another issue we have came accross was the engine smoking when cold a little, this is also cause for concern and should do this.
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If the compression results were quite varied it would indicate wear/poor sealing for whatever reason, and that alone could justify a rebuild and also bits of grit(?) in the engine cant be good!

As long as theres good reason to rebuild it, then its understandable to rebuild with stock parts. Thats why i asked what was wrong with the engine.
 
whilst it's fair enough to rebuild it if it's burning oil and has varied compression i think you're still going to be expecting too much from rebuilding it.

you say stuff like 'get the car running as it should' ....well put it this way, my engine (thanks to me not using booster when it was mapped with it) has cracked a ring. Compression isdown 100psi on one cylinder....100!!!!!! Its burning oil like no tomorrow atm...however this has still made very little difference performance wise. If you hope that rebuilding it to gain even compression will transform the performance and get you right down in the 14s i think you're barking up the wrong tree.

However, what has made a big difference to mines performance recently is selling my powerland header and having to make do with a hotshot for a few weeks. The top end is soooo strnagled now it's like a different car.

Even if you do rebuild it, i can't stress enough, the importance with a big cammed ve of a proper headerand exhaust.

As for c/r's - you can comfortably go to 12:1 if not more if you have 99ron fuel near you - no need for booster. I've learnt this first hand by using it and realising it only gained me a few extra degrees ignition timing in the midrange before the cams switch. Once the cams switch 99ron is more than enough. Especially if mapped well and i presume you wont go back to jez.
 
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