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 Post subject: Re: Our little cultus racer
PostPosted: Fri Jul 12, 2019 3:33 pm 
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Joined: Mon Dec 19, 2016 10:40 am
Posts: 947
Location: NZ
yes Sam you are zoning in.

So the piston lost a piece of it through a seriously lean condition. no other damage noted. It was noted the engine was running extremely perfectly....the bearings are perfect...the rods, the head the valves the other three pistons golden brown on top the bores A1. Marc said its a real shame as the engine was running brilliantly. I noted no oil usage and no oil in the catch can....quite a bit of breathing out the catch can vent which Chris said "heavy breathing engines make power!" and that it did. it only breathed when cold....after a run it was pretty sweet.

So what caused the lean condition???...that is what concerns marc.....the injectors flow test perfectly.
He asked me to look at my wiring. I have noted a broken tab on the no.2 on the plug where the clip fits. The clip was in position when removed however it is possible that with vibration that the clip was allowed to loosen the plug enough to get a sporadic signal to the injector....and probably caused the running on 3 cylinders that we thought was a build up of fuel on the plug....I thought...we should check that....damn it....did I?...no.
on that run the lad drove from 12th to 4th and the car ran fine with all parameters looking great.

The data shows a wicked lean spike for 30 secs...probably or most likely that no2 cyl. Marc commented that it looked like it was not lean for that long but was seriously lean....if the injector failed or just stopped working altogether the engine probably would have been fine.

so marc is unhappy to allow our project to sit idle and has donated a block he will bore to new forged pistons and is getting a price for four new pistons. I want to ramp down the compression maybe 12:1....the rest of the engine is fine. It may not take too much to resurrect and both marc and chris want to see the car back on the track....so Im in it for one more.....minus the hydraulic lifters as long as the price is right. Id only go for this given the fact that the rest of the motor was running awesome and something I have done has caused it.

now the confession. I knew that plug tab was broken but I thought it was holding the plug onto the injector just fine......fecking idiot.


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 Post subject: Re: Our little cultus racer
PostPosted: Fri Jul 12, 2019 6:17 pm 
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Joined: Tue Feb 23, 2016 5:38 am
Posts: 438
Location: Cust
That all sounds like positive progress. 12/1 will work fine, that's what I'm running.

The only thing I'd say is to make sure you sort out the oil supply. You shouldn't need a shim in the pressure relief with a new pump. Make sure the head is good and if it's not use the one off the donor car. If you've got some spare cams see what Kelfords can do with them in terms of a profile for solids, you might be pleasantly surprised both in terms of power and reliability.

I guess you might also want to ask some questions around your ecu config. An injector dropping out needs to raise a red flag. I can't remember whether you can use that in engine protection but ideally it needs to be a stop condition.


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 Post subject: Re: Our little cultus racer
PostPosted: Mon Jul 15, 2019 1:40 pm 
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Joined: Mon Dec 19, 2016 10:40 am
Posts: 947
Location: NZ
Marc is onto it. He is looking into the engine for me. We will rebuild once more....definately want to get the hyd lifters out. He is donating some ID injectors to the cause as he does not like to risk the 28 year old ones. I have to check all the wiring right back to the ECU and replace that one plug on no 2 injector which I am sure was the cause.

Jeez I have been a bit unlucky with this motor... we are going to bring the compression ratio down under 12:1. If the bearings are running fine which they are ill leave the oiling system alone unless removing the hyd lifters increases it some more.


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