Board logo

Iva falied again !
wandr - 20/8/19 at 08:42 PM

Iva retest at Northam today, last time failed on usual sharp edge stuff but engine wouldn't run properly at revs for noise test and speedo check, changed fuel pump for retest and on try out at home held revs fine so thought I'd cracked it, sure enough held revs fine and passed noise test, passed all other rechecks (edges etc) but when dropped in rollers for speedo check refused to pull under load and wouldn't go over 35 mph and struggled to do that. Set up is twin 40 on cvh engine (1.6) with new webcon pump and lumenition ignition, not sure whether to set light to the frusrtrating heap or give it one more try. The difficulty is trying it under load before the next test as examiner told I get one more go then its a full retest !
Slightly good news was the speedo showed 35 mph and the examiners gadget showed 32 (acewell 3100 unit) so set up may be ok if it ever runs right not sure what to check next, any suggestions ?


snapper - 21/8/19 at 05:50 AM

Take it to a rolling road and have it setup properly is now your only option. Itís got to be worth it and cheaper than a full Iva test


rusty nuts - 21/8/19 at 06:34 AM

Have to agree with a rolling road set up , plus it will get the best performance out of the engine


gaz_gaz - 21/8/19 at 06:45 AM

as above get the car setup properly.

I failed in April at Northam. I chucked the car on the trailer and dragged it upto Dale at Bailey Performance. Dale worked his magic and the the end result was a stress free pass at the retest.
It's a bit of a trek but well worth it in my opinion.


CosKev3 - 21/8/19 at 08:11 AM

As above,needs a rolling road session.

It's quite a undersight IMO to not do it before a IVA anyway when you are running twin carbs etc


coyoteboy - 21/8/19 at 11:13 PM

It is hard to get a carby setup running right without a rolling road, or a deserted car park out of town if you don't want to throw the cash at it. But you're building a car, you've already thrown cash at it


theduck - 22/8/19 at 11:04 AM

I had a similar issue on my pinto at Iva, took it rolling road and fixed in minutes. Turned out the valve clearances were completely wrong and abusing no other symptom than a lack of power.


rusty nuts - 22/8/19 at 04:14 PM

quote:
Originally posted by theduck
I had a similar issue on my pinto at Iva, took it rolling road and fixed in minutes. Turned out the valve clearances were completely wrong and abusing no other symptom than a lack of power.


Ideally carbs are the last thing to adjust when tuning an engine, just goes to show how simple things have an effect. Unfortunately the CVH engine has hydraulic tappets so is wonít be the cause in this case. If you havenít already checked then check the valve and ignition timing as well as ignition advance, and are you getting full throttle?