A question about compression (pettit motor)
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Full Member
Joined: Jul 2002
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From: Minnesota
A question about compression (pettit motor)
Hey everybody,
I have a question for all of you. I am thinking about buying an RX7 with a Pettit Racing engine in it. Today, I took it into get a compression check on the rotors. Both rotors were at 6 kg/cm2 or 85 lb/in2.
Is this normal for a rebuilt Pettit Engine? It was explained to me that maybe the reason that the compression was lowered by Pettit to prevent "Pinging" as he called it.
What's your opinion?
Thank you!
Ryan C
P.S. It's the fastest car I have ever been in!
I have a question for all of you. I am thinking about buying an RX7 with a Pettit Racing engine in it. Today, I took it into get a compression check on the rotors. Both rotors were at 6 kg/cm2 or 85 lb/in2.
Is this normal for a rebuilt Pettit Engine? It was explained to me that maybe the reason that the compression was lowered by Pettit to prevent "Pinging" as he called it.
What's your opinion?
Thank you!
Ryan C
P.S. It's the fastest car I have ever been in!
Senior Member
Joined: May 2001
Posts: 697
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From: Mississippi
i have a pettit engine, it is ported and was also dowell pinned. i was told nothing of lower compression. and do not know the exact numbers that they should be at. call cameron worth at pettit. their number is....561-844-2258.....
hope this helps...
hope this helps...
Rotary Enthusiast
Joined: Feb 2001
Posts: 1,025
Likes: 4
From: Huntington Beach, CA, USA
Thats BS. Call Pettit and repeat what he said and see what they have to say. The only way to lower the compression would be to use rotors from the 86-88 TII, which I HIGHLY doubt they did. The compression numbers are borderline too low although if they are perfectly even then thats not so bad. Depending on the price it could still be a good buy but I don't like the idea of the seller lying to you. The car can still give many more miles but I'd set aside money for a rebuild.
Passenger
Posts: n/a
I think they only use 3mm apex seals and that will give a little bit of a lower reading
Those numbers are fine. You will be surprised about how many people think they have 120psi compression on their motors
6kg or 6.5 kg is good do not be affraid.But the numbers must be even....
-Rikki
Those numbers are fine. You will be surprised about how many people think they have 120psi compression on their motors 6kg or 6.5 kg is good do not be affraid.But the numbers must be even....-Rikki
Senior Member
Joined: May 2002
Posts: 494
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From: Austin Tx
the numbers are fine.. Its almost impossible for both rotors to be losing compression at the exact same rate. Im sure it could happen but ive been around alot of dying rx7 and have never seen it..
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