NITROUS OXIDE ( nos / n2o ) advice forum

ODIHAM !!!!!! that sounds familiar. It that in Surrey?

Cheers Trevor, ive been spending many more hours in the garage.

It doesnt look like i will be able to fit the splitter blocks as i had planned. The direct port is just plumbed together at the moment to seal the system. As the d blocks and plumbing squeeze in ok i will upgrade these later.

I will just run upto 150 bhp on the old set up for the time being.

Not far from Fleet.
Less than an hour back to Pompey for me.
Was a good day, you should have come

First fire up in 18 months bedding cam in.
Needs tune up asap

http://www.youtube.com/watch?v=ciofc3Kk ... tube_gdata

All ready then




Austin

It's too late now but you should have had the RPM MUCH HIGHER than that for running the cam in. The higher the RPM the better it is. Likewise ignore all the old wives tales about running an engine in at low rpm, because what you really need to do is thrash the hell out of it. The ONLY reasons any engine builder tells you to take it steady, is because they've either built the engine badly or they have no confidence in their work and they hope that by driving steady, it'll last long enough to get past the warranty period.

Warranty? lol
I have faith in my engine builder.
I ran the engine between 3 and 3.5k for 5 mins, checked fluids etc, then again the same for 2 x 10 mins.

5+ K would have been better but at least you didn't let it idle.

my car is ready for the MoT thanks to the guys at TrackVRoad but is still running rough after all the 'usual' checks.

A compression test is being carried out this morning. The mechanic suspects a valve is being held open, possibly due to incorrect valve clearances.
I am praying there is no damage to be found.

I'm with Trev on the running in procedures. Many times an engine that has been "gently" run in makes less power than one that has been thrashed from day one. only thing I ever worry about is oil pressure, wind it over on the starter until the light goes out, then start it up and thrash it up and down the road. Treat it like it's going to be treated. it'll thank you for it.

Gunson Hi-gauge bought from halfrauds.....

All pots were approximately 100 psi on the first crank and 120 on the second.

3 cranks 5+ cranks
1. 130 140
2. 135 150
3. 140 150
4. 140 150
5. 135 140
6. 140 145
7. 140 150
8. 135 145

Them pressures are excellent IMHumbleO, i was only hoping for 120ish on a 8:1 CR.
I guess TrackvRoads tester is faulty or the rings hadnt been given a chance to bed in

I took the car for a short drive yesterday. It started fine, ran a little rough with a struggling idle from cold. I let it warm then give it a few full throttle blasts from low revs past 5000.
There were very flat spots, particularly just below 4000.
On the way back, with the temperature at a normal 90, the engine was very rough at low revs and i had to keep blipping the throttle to keep it going and get it back in the garage.
I let it cool and pulled the plugs that were all very sooty.
I had to wait till today to get the new comp tester as the one i borrowed wasnt working.

So what now? Maybe the cam can be made to work once the megasquirt is installed and mapped?

First i will pull a rocker cover and do a quick check of the cam timing.

Thats sounding much better Del

Is that @ WOT?

Bill

What indications have you had that there's a problem???

Sorry Trevor there are a few gaps in the story in this thread.

I did the fire up and 20 mins of bedding the cam in and had the car booked in at a TVR specialist in Clitheroe to finish off a few jobs, set the suspension geo and put the car through its MoT. The car is now fully decatted btw.

They completed all the work and i now have the MoT but they were concerned with the engine running very rough with an intermittent spitback up the inlet. Initial thoughts were cam timing or something mechanical at fault.

Heres where something went amiss!..... their compression tests were only giving 60 psi on all pots, hot and cold (see my own compression results above!).
They checked the valve lash and a few had settled from the 22 thou to 30 thou (so no biggy) but 1 adjustable pushrod had come very loose on number 6 exhaust. This was fixed and the 'spitback' issue was resolved. But still running as i described above.

I dont think there is anything mechanical wrong with my engine now. I think its overfuelling badly and needs a proper retune.
It is thought that my ecu, trick afm from 'Torqueflow' etc are not tuneable enough for the cam i have fitted.
I am currently fitting a wideband sensor and gauge, and a Megasquirt direct fire ECU kit is on the way so the distributor and AFM will be ditched and it will all be fully mapped properly.

I will also have a second map when the nitrous is activated. I was thinking of a 6 degree retard throughout the revs but open to suggestions. I will be running a 150 shot for now.

set out on my maiden voyage today to take the car to get megasquirt wired in and mapped. It ran ok despite the dodgy fuelling and wild cam. All dials looked ok and the engine temp was nicely settled just over 70.


Only made it to the motorway, about 40 miles from home and lost oil pressure.



Seems some idiot (me) had missed a spacer behind the pulley which had moved forward pulling the drive gear from the oil pump.



So back to the garage in bits it is again !

AWWWWW mate, condolences

It lives again and all seems ok for now.

If that's the case you've been EXTREMELY lucky.

I know Trevor.
Going for a very careful run out today. I will have to try and keep an eye on the road as i will be mostly looking at gauges.

Regular stops and checks also i think.

If all goes well then i will be driving 200 miles to Santa pod next Friday for the TVR shootout on saturday.

So an update.

I took the risk and headed to Santa pod.
The fuelling had been tweaked and all seemed well until i hit the M40 about 180 miles into the journey. 3rd lane of the motorway cruising and the engine 'let go' with a very loud clatter.
AA to the pod, RAC home after the weekend.


Full stripdown on Saturday revealed some worrying damage

Main and big ends shot. Number 8 big end and number 4 main had both spun the bearings.



Bent number 8 big end bolts bent



Number 8 exhaust valve and chamber



Ceramic coating damage on number 8 piston



Crank journals



Followers



Cam bearings



and nasty wear on the blocks number 4 main

That's the WORST damage I've ever seen ANY engine suffer without a main component failure.

I will take that as a compliment

Its fixable. Just need to weigh up the best method.

A good engineering company should be able to line bore the mains to salvage the block but it's going to need a new set of rods, because I wouldn't trust a rod after it had been abused like that (even though it could be saved by good engineering) and although the others didn't suffer quite as badly, they got too close for my liking.

If it makes you feel any better I had a similar experience with the first performance Rover motor I built. Spent all I had on the best bits but made a minor mistake with the build, that lead to a major failure within a couple of runs. I couldn't afford to rebuild it with new parts, so I re-built it using the damaged parts and only replaced the absolute essentials (a set of cam bearings that had fallen out and mangled up everything they encountered in the rotating mass) and then went on to win the Super Street and the Rover Challenge Championships that year. That was despite big lumps missing from the piston skirts, the liner skirts, the odd conrod or two and the odd cam lobe or two.
After that I stopped worrying about certain aspects of engine building, needing to be as perfect as I had up to that point.

For the line boring option i would need a very reputable machine shop.

My pistons are close enough already to the heads and i couldnt afford to end up with them any closer. Another problem with line boring the RV8 is that the caps are steel and the block is ally so the tool can wander due to different resistant forces.

It may be possible to not line bore and to pin the number 4 main bearing in place i believe.