wich engine should i use
Old [Sch|F]ool
Joined: May 2001
Posts: 12,868
Likes: 573
From: Cleveland, Ohio, USA
My steel 2mm seal engine has 60k kms on it. I run it up to 10k on occasion although I try to keep revs below 9k for transmission life. Compression is degrading slowly but that is mainly due to the chrome coming off of the '84-85 rotor housings.
Thread Starter
Full Member
Joined: Sep 2012
Posts: 138
Likes: 0
From: Denmark
yes 9.7 is good , better than the early 9.2 heavy 13b rotors that have less gear fixing pins
they weigh close to s3 12a rx7 rotor specs, so will spin like tops in comparison, and make better TQ down low
( despite 4 large ports being exactly what you dont need to make good low down TQ )
carbon apex seals just suck/// the housings are designed to take steal, and mazda went there with good reasons
carbon doesnt last long , and it may seal great now,, but dont expect 50 000 km
if you where building the ultimate NA rotor motor then you would be getting the housings lapped and purchasing the ultra lightweight ceramic seals
which give you the mass advantage of carbon
with the hardness advantage of steel
they weigh close to s3 12a rx7 rotor specs, so will spin like tops in comparison, and make better TQ down low
( despite 4 large ports being exactly what you dont need to make good low down TQ )
carbon apex seals just suck/// the housings are designed to take steal, and mazda went there with good reasons
carbon doesnt last long , and it may seal great now,, but dont expect 50 000 km
if you where building the ultimate NA rotor motor then you would be getting the housings lapped and purchasing the ultra lightweight ceramic seals
which give you the mass advantage of carbon
with the hardness advantage of steel
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
housings actually look great.
we ran 2 cars, a completely stock 87 GXL, and the race car which was an S5 engine with haltech + premix, and the factory car always had nice plug color, and the haltech car didn't, it was always black. i used to blame the haltech, but i think its the premix
Rotary Freak
Joined: Jul 2003
Posts: 2,199
Likes: 9
From: Oakville, Ontario
I have been using factory steel apex seals in my motor for 7 race years on pre-mix. S5 9.7 rotor assembly in an S4 TII set of housings. I buzz it to 9200 rpm on occasion and most of the time to 9000 rpm. The compression and everything are still good and it made enough power to win a 3 Hour enduro this year and win the ST2 Class Championship. I am sorta scared to pull the motor apart as it is running so well now and super reliable.
My buddy went to the carbon seals and he had to rebuild the motor every 2 years. Granted he was buzzing to 10,500 - 11,000.
Eric
My buddy went to the carbon seals and he had to rebuild the motor every 2 years. Granted he was buzzing to 10,500 - 11,000.
Eric
Just tore down my engine and I've had various bouts of 8.5k to 10krpm with steel apex seals: take a look...
https://www.rx7club.com/build-thread...-925525/page5/
yes it still started and ran and drove.
https://www.rx7club.com/build-thread...-925525/page5/
yes it still started and ran and drove.
Thread Starter
Full Member
Joined: Sep 2012
Posts: 138
Likes: 0
From: Denmark
great advices from everybody thank you.
Is it realistic to just take a good 4 port engine rebuild and clean it up, put in a bridgeport and put it back together with used parts and still get a reliable engine? off course i will tjek all measurements and specs..
And can i expect 200 something HP frome that simple a build?
Is it realistic to just take a good 4 port engine rebuild and clean it up, put in a bridgeport and put it back together with used parts and still get a reliable engine? off course i will tjek all measurements and specs..
And can i expect 200 something HP frome that simple a build?
great advices from everybody thank you.
Is it realistic to just take a good 4 port engine rebuild and clean it up, put in a bridgeport and put it back together with used parts and still get a reliable engine? off course i will tjek all measurements and specs..
And can i expect 200 something HP frome that simple a build?
Is it realistic to just take a good 4 port engine rebuild and clean it up, put in a bridgeport and put it back together with used parts and still get a reliable engine? off course i will tjek all measurements and specs..
And can i expect 200 something HP frome that simple a build?
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