My rebuilt engine

[CMA]

What about if you disconnect all temp senders? Will that cause the ecu to think 20deg and start?

[stylussprinter]

Interesting thought , I'll leave it till tonight and try that

[norma]

my money is still on the plugs - PLEASE TRY SOME STANDARD ONES

[MattD]

Pretty sure its about 2mm off the head face of a silvertop
to get to 10.5:1 CR, plus a bit more to get to the unknown 11-11.5-12:1 for Dunnells special detail.
Plus you don't know how the valves overlap &/or piston crown shape.

So I'd be very careful about putting standard long plugs in without asking Dunnell first.
Could be an easy way to bend a valve or punch a hole in a piston (or all 4 !).

Just my 2 pennies.

[mikeb]

I agree with Matt, Paul Dunnell had it running on the dyno! Got to look at something added to the engine. Must be electrical or fuel. Mike

[mikeb]

Another thought - did Dunnell check the start up enrichment part of the software?

[Ned]

Before you load up and take it back renew the coolant temp switch, bear with me.... it wont start when cold but once you have cranked it for ages it induces heat and even trys to start then the air and fuel mixture gets somewhere close enough it starts and then is happy bunny left to cool down completly its not happy...renew coolant temp sensor...they give issues on all makes where the resistance value changes as temp increases so if it does not react correctly (which is what i think is happening to yours) if your sensor is not working then it would not run as you have discribed. plus they are not dear...Phil

[stylussprinter]

Funny you should say that Phil , I was intending to poor boiling water over the sensor housing where it goes into the Raceline waterail , to see if that was the cause . Haven't done it before as Dunnell said the ECU logged no problem apart from air sensor. I'll report on that then

[stylussprinter]

Mike ---- I haven't asked him that but assume he has when I posted it back to him for problem solving Norma ------- the valves in this full race head are larger than the big valve head that was cracked so to try standard plugs 10mm's longer would be very risky ---- he won't have put shorter ones in for no reason .

[stylussprinter]

Well Phil/ned gets the prize for this quizz I wedged a fan heater up against the water temp sensor where it goes into the waterail (2kw) and left it there for 10 minutes or more . Took it off , poured boiling water directly over the bronze housing on the sensor -------------- it started after 10 sec's So the water inside the waterail obviously wouldn't have been 90 degrees but just enough to fool the ecu into thinking it was in hot running mode
SO ---- what is actually wrong , my sensor or the ECU Not to worry , I'll just have to remember to take a kettle of boiling water with me to the circuit in future ----- scrutineer will think I'm a fanatical engine ' bling ' nutter

[stylussprinter]

Sender duly ordered and will arrive tomorrow via Online Automotive at Northampton Thanks to Matt for locating the source and at £8.27 plus carraige.

[hearbear]

Thanks for the coffee Rob glad it looks like you have got to the botton of it.

[stylussprinter]

You're very welcome George , anytime you pass I'm more than likely to be here Only sad thing now is there's no where for me to test the car out before 2011 sprint season gets underway -- ugh . I had planned to test at Goodwood after the engine was back in but too much time has been wasted . It's the first Tuesday of the month for general testing but the weather's not going to be very reliable to book for December

[CMA]

Good news, glad you found the issue.

[stylussprinter]

Sensor fitted , started first time ---- problem solved Never entered my head that the water temp sensor may be duff because it was on my engine before rebuild and on Dunnell's dyno , although I had checked out the wiring back to the ECU plug .

Thank you all for the many clues to investigate -------- reckon I owe Phil a pint or two though when we meet up again

Just had an email from Paul to say he didn't use my sensor or waterail on the dyno. Also a warning that on NO account should I fit standard NGK R 13 plugs due to the machining on this head.