I'm finally getting my 95" big bore kit installed and need to know what the highest compression I can still run the stock starter? I'm going to be somewhere between 9.5 and 10.25.

I figure there are 2 options if I pass the threshold:

1. Upgrade to a bigger starter. What size?
2. Compression releases installed once the heads are off and at the machine shop. Anyone ever do this?

Thanks.

 

10-1 no more.

 

lionm13 hit it dead on the head at 10:1.
Usually a stock starter will start to grunt at anything above 10:1. I have seen stock starters crank engines with much higher compression, however Its all in how the stock starters built, some are just stronger than others.

 

I'm in that 10.25 realm and I went with the Harley S/E releases. The starter will crank it up with out using them, BUT, it does't like it one bit. Get the compression releases installed while it's torn down. Hell of a lot cheaper than a new starter.

 

Definitely have the machinist install compression releases, Goodson has some good ones. I'm at 10.8:1 compression with the original starter and cables, but am bumping that to 11:1 now. Down the road I'm planning on upgrading the starter and just as importantly the cables...


K.

 

10:1 is about the limit. stock starter will work at a higher comp. BU NOT FOR LONG. releases are a no-brainer when the heads are off. when its time for a starter go with a better than stock replacement. better cables sure wont hurt either. steve

 

also depends on camshaft choice. use one of the calculators to figure your final comp. steve