broke side seal 700 miles on rebuild?
#1
broke side seal 700 miles on rebuild?
I have my s4 t2 with s5 rear plate street ported with 9.0 rotors ra superseals new springs side seal springs and all clearenced triple checked it all when I put it together . leaving dyno other day just made 386whp with bad ignition cut up . around 6700rpms car would fall on its face so I figured new plug wires . just put in a set of new plugs before dyno . did one hard 1st -3rd pull. Top of 3rd i felt loss of power . and I thought maybe I killed plugs again . did a compression test and it was 60 60 0 .put atf in the motor still nothing thinking it was a stuck seal took my turbo off to inspect seals there all intact and move in and out fine . all clean inside . I'm lost for ideas has to be a side seal right? Car barley holds an idle
#2
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when you pull it apart look for damage on the top edge of the intake ports. if you go too far, the side seal isn't supported and can drop into the port, which will break them
#3
Rotary Motoring
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Well, your compression test indicates one side seal completely stuck down in the groove and possible side seal, corner seal and/or apex seal damage on the rest of the faces.
Its gotta come apart, so you will see the carnage soon enough
Are you certain the hesitation wasn't detonation?
Its gotta come apart, so you will see the carnage soon enough
Are you certain the hesitation wasn't detonation?
#4
Rotary Motoring
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True, but remember when you look at the top edge of the port that a broken corner seal will drop into the port and gouge the closing line too.
Usually if there is a problem with the ports it causes problems at low rpm when the side seals have more time to drop in on extension.
I have found with the stronger apex seals in my engines it just means detonation takes out the corner and sideseals and warps the apex seals and crack the plates.
Usually if there is a problem with the ports it causes problems at low rpm when the side seals have more time to drop in on extension.
I have found with the stronger apex seals in my engines it just means detonation takes out the corner and sideseals and warps the apex seals and crack the plates.
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#14
Rotary Motoring
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My experience with my 720cc/1600cc and a Walbro 255HP is that the fuel pump will drop pressure and cause hesitation/detonation and you won't see it in the AFRs.
I swapped out to a '044 after describing what my car was doing to Bryan@BNR and taking his advice to upgrade the pump. The hesitation went away.
Also, what fuel and boost.
Again, detonation feels like hesitation. On 9:1 rotors and pump fuel you can get auto-ignition from 12-22psi depending on many factors.
With 386RWHP I would guess you are about 14-15psi boost.
Little things like the gas station pump not switching fuels right, the additive not getting added, recirculating crank pressure to the intake, water in the gas pick-up area, etc etc can lead to detonation at 14psi on 9:1 rotors.
I swapped out to a '044 after describing what my car was doing to Bryan@BNR and taking his advice to upgrade the pump. The hesitation went away.
Also, what fuel and boost.
Again, detonation feels like hesitation. On 9:1 rotors and pump fuel you can get auto-ignition from 12-22psi depending on many factors.
With 386RWHP I would guess you are about 14-15psi boost.
Little things like the gas station pump not switching fuels right, the additive not getting added, recirculating crank pressure to the intake, water in the gas pick-up area, etc etc can lead to detonation at 14psi on 9:1 rotors.
#15
Rotary Motoring
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it should have blown at 300;miles if that's the case
Hard to predict. Last time my set up went it was a bad batch of gas that was causing major hesitation (knock sensor pulls timing).
I kept racing anyways and the car had an oil leak after that.
Next race event and after driving on the street (fresh gas no more hesitation/detonation) the leak was getting worse so I took a hard look and found-
Cracked rear iron at the oil filter mount (reinforced S5 block).
Took the engine apart-
3mm Apex seals cracked in half, but still in place. Sideseals broken, corner seals broken.
Everything still in place and had not caused interference issues even while racing- I got really lucky.
Hard to predict. Last time my set up went it was a bad batch of gas that was causing major hesitation (knock sensor pulls timing).
I kept racing anyways and the car had an oil leak after that.
Next race event and after driving on the street (fresh gas no more hesitation/detonation) the leak was getting worse so I took a hard look and found-
Cracked rear iron at the oil filter mount (reinforced S5 block).
Took the engine apart-
3mm Apex seals cracked in half, but still in place. Sideseals broken, corner seals broken.
Everything still in place and had not caused interference issues even while racing- I got really lucky.
#16
Wow that's crazy and it was 16psi with it cutting up at 6700rpms cause of ignition . should have made easy 400whp it had shell 93 . I dont want this to happend again it must have detonated . **** sucks . all my apex seals are fine 95 psi on both rotors . housings are nice and clean from what I can. See on exhuast side
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+1. you need to walk before you can run. so start the tune in vacuum, then 0psi, 2psi, etc, and work your way up. just slapping it together and running 15psi on a "basemap" is just asking for a blown engine
#20
FC guy
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you also said timing was off for almost 500 miles
Im giving my advice because I was in the same situation except my car was running perfect.
It was base tuned, quick street tune. Doesnt take much boost to do some damage, literally a single aggressive pull without being fully tuned is all it takes
Im giving my advice because I was in the same situation except my car was running perfect.
It was base tuned, quick street tune. Doesnt take much boost to do some damage, literally a single aggressive pull without being fully tuned is all it takes
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#22
Rallye RX7
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Pop the exhaust manifold off and move the rotor in question to where the apex seal is visible through the exhaust port.
first visually inspect seach apex seal. Then, press on each apex seal, check and see if you got a sticking apex seal. You should have some springyness to it. If one is stuck try some carb clean and work it with a plastic piece or your fingers
if you have 60 0 0 then 1 apex seal affects 2 chambers.
first visually inspect seach apex seal. Then, press on each apex seal, check and see if you got a sticking apex seal. You should have some springyness to it. If one is stuck try some carb clean and work it with a plastic piece or your fingers
if you have 60 0 0 then 1 apex seal affects 2 chambers.