[6pack] Pinging Engine

[Andrew Uprichard]

I put a 123 distributor on my last TR3 and it worked a charm.  

I have one in my recently-finished fast-road TR250 and it seems to be fine.
I will be putting the car on a dyno in a couple of weeks, so we'll probably
vary the settings then for maximal performance.

Andrew Uprichard

-----Original Message-----
From: 6pack-bounces at autox.team.net [mailto:6pack-bounces at autox.team.net] On
Behalf Of Tomislav Marincic
Sent: Monday, April 09, 2012 2:45 PM
To: 6pack at autox.team.net
Subject: [6pack] Pinging Engine

My TR6 is pinging after a high performance rebuild, and I can't stop it. 

 

I've done lots of things (high octane via xylene, retarded ignition, colder
plugs, richer mix) but it's starting to look that either the machinist
screwed up the head, or I've just built a monster.

 

I had a few specific questions:

 

1.      Cranking compression. The engine was built to 9.5:1 specs,
45.6cc/chamber. My cranking compression hot is 195 +/-5 psi with a Goodparts
GP-2 cam, which strikes me as 10-15 psi high. Anyone else have a comparison
of nominal CR vs. compression with a similar cam?

2.      Timing. Jeff at Advanced Distributors does great work, but he
refuses to tell me what specs he built my distributor to, which is not
helpful. Does anyone have experience with the 123 Distributor, which allows
the timing curve to be manipulated? Is that distributor compatible with the
MSD 6 series ignition?

 

Thanks for your help. If I hadn't used forged pistons, I'm sure I'd have
blown a ring land by now.

 

Cheers, Tom

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