Author Topic: A7 engine rebuild - several questions  (Read 1986 times)

Online berger

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Re: A7 engine rebuild - several questions
« Reply #30 on: 23.09. 2018 19:44 »
I have not been to the pub, if you are not on high comp 8to1 and over I would set timing 35 degrees if over 8to 1 38 degrees

Online Triton Thrasher

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Re: A7 engine rebuild - several questions
« Reply #31 on: 23.09. 2018 19:52 »
I have not been to the pub, if you are not on high comp 8to1 and over I would set timing 35 degrees if over 8to 1 38 degrees

As a rule, higher compression ratio requires less ignition advance.

Online JulianS

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Re: A7 engine rebuild - several questions
« Reply #32 on: 23.09. 2018 20:27 »
The BSA Data books for 1960 and 1961 gives 35 degrees for A7 iron head 7.25:1 comp and 38 degress for A7ss 8;1 compression.

Online berger

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Re: A7 engine rebuild - several questions
« Reply #33 on: 23.09. 2018 20:38 »
yes triton thrasher thanks for the correction , i'm going to join big jim in the pub *beer*

Online berger

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Re: A7 engine rebuild - several questions
« Reply #34 on: 23.09. 2018 21:07 »
that's it then I will not be sticking to the rule, I will stick with what julian found *smile* *beer* *fight* *problem* *bash* *shh*

Online Triton Thrasher

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Re: A7 engine rebuild - several questions
« Reply #35 on: 23.09. 2018 22:10 »
The BSA Data books for 1960 and 1961 gives 35 degrees for A7 iron head 7.25:1 comp and 38 degress for A7ss 8;1 compression.

Two different cylinder heads.

Online berger

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Re: A7 engine rebuild - several questions
« Reply #36 on: 23.09. 2018 23:10 »
bloody spoil sport and I was doing so well *sad*, o well  pub tomorrow *beer* *countdown*. so what do we advise the chap 38 degrees or 35 degrees, could have 3 degrees , good singers they were *dribble*  *lol* *whistle* *good3*

Offline edboy

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Re: A7 engine rebuild - several questions
« Reply #37 on: 24.09. 2018 01:17 »
with the head off.i have always measured the bsa fraction btdc given in the manual on the compression stroke and then stamped or marked the timing side breather to a corresponding dot on the inner timing cover. not my idea but so easy to set timing again. a degree disc may be more accurate so mark it anyway.

Offline Berni

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Re: A7 engine rebuild - several questions
« Reply #38 on: 26.09. 2018 20:44 »
Hello guys,
taking in account, that I have standard pistons, instead of high compression ones, and as much as possible oversize, I will try at 35° and see what happen. In addition I can do also  do the distance measurement. If the engine "pings", hope this is the right word, I have to adjust.  *smile*
Hope to get "Maggy" back to the road.
Thanks a lot.
Berni
Germany A7SS

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Re: A7 engine rebuild - several questions
« Reply #39 on: 26.09. 2018 20:51 »
G'day Bernie.
An A7SS should be 3/8" btdc. If it pings back it off to 5/16".
Cheers
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