As I've got a perfectly good B18 sitting on my garage floor, I thought I'd give it a rebuild over the spring/summer and get it off to a new home. The original problem with this engine was that it shared compression between 2 and 3 caused by either the head or block being distorted. No coolant loss, but not the best for performance either.

I've taken the head in for cleaning and will be doing the bottom end in June. So, while I was waiting for the battery to charge in the 122 after it's winter rest, I thought I'd spend the afternoon wondering why I sent a head to John Parker for rebuilding and porting in the first place. Man, I'm kicking myself all over again.

Here's the start point - you can see where the performance gains are to be had and you certainly don't need to spend a grand to get it done. The original B18 head was in great shape with no wear on the guides or valves. So the rebuild is mostly about time and preparation.

Look at the restriction just before the intake valve! The exhaust is hampered by a short side radius that is less like a radius and more like a corner and has a built in restriction just behind the valve. The back wall of the exhaust is also tapered in towards the valve guide. The entire time, I'm thinking "and they thought that exhaust gasses are going to like getting out of this port how?".



So off with my compressor and die grinder - total time including cleaning to get the intakes ported to 120 grit and the exhaust to 240 grit was a hair over 2.5 hours. Good thing I waited almost 2 years for VPD to get my 2 litre head done!

Here we go.

First up was to hog out the restricitons with my flame burr, this ended up being my favorite cutter for this head. I reshaped the back wall of the valve pocket and increased the overall size. I probably will have to replace one exhaust valve seat where things got a little out of hand - we'll see if it is salvageable (it still seals). I also took the lip off the combustion chamber the same way I did on my B20.



No more restriction here!





There is not much that you can do with the ports. The general idea is to clean them up - the intake has a restriction just behind the sealing rings that was hogged out and the exhaust is biased towards the top of the port (sort of rounded out a little) to help flow.



This is a good shot of the new back wall of the exhaust valve - this should help.



That's it for now. I've got to CC the combustion chamber and calculate how much to skim off the head, then take it back for regrinding the seats and that will be it for this head.

Time to invest in a flow bench!

Ya, or a reasonable facsimile of one would do. I'm not to worried about this head as I'm just trying to replicate what existed in the VPD head. While I don't have the flow measurements, I think this one would be at least as good as that head.

I still want to build a flow bench. I've got all the vacuum motors I'll need to do anything less than a big block V8... just need to build the rest! Oh, and find space in my garage for it.

Space, what is that? I'm going to have to blow the roof off my garage to get the stuff in it that I have now! You get use to working around stuff - in an ideal world we'd have a club garage with some of the almost never used tools in it - maybe we could find a place in Vulcan

Got the head back from the machine shop. Three angle valve job, surfaced, and new bits and pieces - total time 4 days, cost around $250 all in. Sure glad I sent that head to Vintage Performance and waited over 2 years for it to be returned .

Now I have to strip the block and get new bearings, polished crank, decked, and generally inspect the bottom end. The head needed 10 thou to clean up - so my guess is that this is where the compression sharing was - the head was out of spec, the block is probably fine. This is what happens when you slap on a random head onto an unknown bottom end. Thanks again to the previous owners.