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Old 23rd October 2019, 11:06 PM   #1 (permalink)
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Comp loss after Dyno.

Iv had a bit of bad luck with my build.
Back in March I delivered my car to a company ďno name droppingĒ (just yet) who have done a fair amount of work. Non to the block and head. Just fuel pump, trigger kit. Link ecu, exhaust ect. Brakes, clutch, service, water pump cam belt

One of the first jobs I ask to have checked was the oil pressure and compression tests. No point spending lost on other bits if that was bad to start with right!?

Results 1:155 2:160 3:160 4:155 5:150 6:160.

Good bill of health reported. Cool right carry on with all the other bits.

So the car has all the works done and finally 2 weeks ago makes its way done to the Dyno. 506hp at the crank. Not bad. Not amazing, should be nice to drive.

Now apparently they had an issue with tick over and the trigger kit needed some adjustments, I didnít think anything of it. Bearing in mind Iv not been about for any of this. Iv been feed info via messaging,

Got that sorted. And allís well. Because Iíd had the flexi sensor fitted. I could run a 50/50 mix of hi Ron and Ethanol fuel, to give me a better map and an extra 7%. For 250£ thatís seamed good value for money. So Iv gave the go ahead for that.

But when it came to it they had the Idling issue again, on further inspection it turns out cylinders 2 and 6 are now down to 90 and 80 psi!

Now keeping in mind that this cars not been driven about and just shunted about the work shop since its last comp check, why would it have lost compression so fast. On two different cylinders.

Iím not a total tool when it comes to motors, I know shit happens,, but am I picking up the peaceís of someone elseís mistake? The car was already 480ish before it went to be worked on. So itís not like Iv added massive gains to a stock Motor. Sheís had a multi layer gasket already and baffle in the sump. Thatís about it,

Could this be a result of poor set up? If so how do I prove this. I feel I could be told anything to make sure Iím the one left with a huge bill and the mercanic washing there hands of it, even if it was damage caused by the Dyno guy. Or even the Mercanic who set it up.

Or is it just a case of. Yeah your car your problem, this is sort of the feeling Iím getting, as Iím told you have these issues in the pursuit of power!
They think itís a head issue with the valves letting by or not seating, and need to be reground, but Iím told the engine needs to be dropped to take the head off and inspect is that right?

20 hours of labour 2k roughly to have put right.

How do I go about this!?

Whatís peopleís thoughts and experiences?

TIA
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Old 24th October 2019, 12:03 AM   #2 (permalink)
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The closer you push to the limit of what an engine can take the more catastrophic any issue becomes. Maybe there isn't enough cooling at the dyno and the map isn't pulling enough timing or boost at high IAT, one bad pre-ignition event is enough to cause big problems.
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Old 24th October 2019, 08:47 AM   #3 (permalink)
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The one bit there that rings alarm bells is

“ apparently they had an issue with tick over and the trigger kit needed some adjustments,”

Trigger kit only needs adjustment once to set timing offset with a timing light.
Needs checking through the Rev range to ensure no drift but other than that...done.
If it needed adjustment after the dyno....was the timing doing what the ecu thought it was?
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Old 24th October 2019, 09:13 AM   #4 (permalink)
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Quote:
Originally Posted by lightspeed View Post
The one bit there that rings alarm bells is

“ apparently they had an issue with tick over and the trigger kit needed some adjustments,”

Trigger kit only needs adjustment once to set timing offset with a timing light.
Needs checking through the Rev range to ensure no drift but other than that...done.
If it needed adjustment after the dyno....was the timing doing what the ecu thought it was?


Well thatís it. Letís say for arguments sake it wasnít. And the ecu wasnít set right against the trigger.
Would this have caused problems? Iím guessing yes pre detonation? When the valves were not closed!? So knowing what values have burnt out. Ie inlet or exhaust, will determine how for off the timing was?
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Old 24th October 2019, 11:24 AM   #5 (permalink)
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One possible opinion is the trigger kit was set up incorrectly giving massively advanced timing and broke a ringland due to increased cylinder pressure.

To be honest any discussion is pointless without knowing the failure point.

If you have lost confidence in them I would pull the car away to somewhere independent. Have it inspected and then make a judgement as if a legal root is possible to recover your costs.
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Old 24th October 2019, 12:04 PM   #6 (permalink)
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If you have lost confidence in them I would pull the car away to somewhere independent. Have it inspected and then make a judgement as if a legal root is possible to recover your costs.
Agree with David here...
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Old 24th October 2019, 09:07 PM   #7 (permalink)
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What David said
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Old 24th October 2019, 09:46 PM   #8 (permalink)
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Setting ignition timing properly before any fuel injection occurs is critical. I'm not much of a tuner but improper base timing makes it possible to have the spark occur when the intake valve is open and combustion will occur in the intake. Good way to blow off rubber hoses, break intake gaskets, damage sensors, etc.
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Old 27th October 2019, 05:53 AM   #9 (permalink)
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No need to drop the motor to lift the head.

Way i see it:
Bent valves, over rev or cam belt problem (should effect all cyl though).
Burned valves, tuning issue.
Broken ringlands, knock ie tuning issue.
Other, bad luck.
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Old 28th October 2019, 10:08 AM   #10 (permalink)
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Feel for you mate what a disaster. Clearly a case of some negligence. Won’t be easy will end up blaming each other as usually happens in such case.
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Old 28th October 2019, 08:41 PM   #11 (permalink)
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Feel for you mate what a disaster. Clearly a case of some negligence. Wonít be easy will end up blaming each other as usually happens in such case.
Hard to say when such things happen. I would say though that incompetent tuners rarely know that they are, it's on the consumer to be able to identify these people and walk away before they do more damage. RB26s are not cheap to rebuild, especially these days.
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Old 28th October 2019, 09:36 PM   #12 (permalink)
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So bit of an update.

Engines out. Cylinders and bores look good.
Thereís apparently a bit of pitting on the effected valves, heads off to be tested in the next few days for a vacuum test,
All the cylinders and valves look good, Iv been told thereís no damage due to poor testing or installation, no signs of detonation! I guess the head vacuum test results will show the loss of compression, il await the results before I decide which way to go next.

Iím in the southwest, and the nearest place to have the engine Forged (if I decide to go that way) is a Company in Plympton called engine tuner. Has anyone had there pride and joys forged there?

The more I learn about these engines the more I know how critical the work done on them is.

The thought of someone (having a go) on my lump worries me some what!

Cheers for all the advise and comments so far.
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Old 28th October 2019, 09:45 PM   #13 (permalink)
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Originally Posted by TerryTibs View Post
So bit of an update.

Engines out. Cylinders and bores look good.
Thereís apparently a bit of pitting on the effected valves, heads off to be tested in the next few days for a vacuum test,
All the cylinders and valves look good, Iv been told thereís no damage due to poor testing or installation, no signs of detonation! I guess the head vacuum test results will show the loss of compression, il await the results before I decide which way to go next.

Iím in the southwest, and the nearest place to have the engine Forged (if I decide to go that way) is a Company in Plympton called engine tuner. Has anyone had there pride and joys forged there?

The more I learn about these engines the more I know how critical the work done on them is.

The thought of someone (having a go) on my lump worries me some what!

Cheers for all the advise and comments so far.


Engine tuner is well known, especially with Subaru lumps, might be worth inquiring on the Scooby forum.
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Old 28th October 2019, 09:57 PM   #14 (permalink)
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When I bottled doing the actual rebuild of mine I put all the bits on a pallet and sent it up t o Rod Bell, he built and sent it back to me to put in.
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Old 29th October 2019, 12:08 PM   #15 (permalink)
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Don’t take a risk with someone not knowing an RB.

You could try asking Rick Wood at CNC heads. His work is always top notch and is no stranger to an RB. You also have Tim Radley at Race developments in Glostershire.
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