PetenAli's WBX 2500 engine build

[Paul Weeding]

A fiver a pop though...

One of those "it is, what it is" situations...

Better to buy new than reuse old ones

[silverbullet]

Ordering a dozen or so in the morning...

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I found 4 dome nuts in superb condition so they went into the mix. Swapped the timing gear for a -1 because I wasn't happy with the clearances when it was stone cold (something funny about the eccentricity if the gear that I couldn't readily identify)
Double check the valve timing and got it closed:

Reworked the valves with a 30 degree back cut, ended up doing them on our Jones & Shipman universal grinder, these look more like the part:

Next job, get them lapped in...

[silverbullet]

Delays delays....

Waiting for a new piston ring gapping machine to arrive from the USA, waiting for some more carbide burrs to arrive so I can do the last awkward corners on the heads...
At least my double thrust Glyco cam bearings arrived from Florida for my own 2500

[PetenAli]

Looking great Ian. Good to see the green sealant between the case halves and the new end cap!

Those valves look the business as well.

[silverbullet]

I bought a small quantity of those end caps (seven) via BW, I think I may have the largest stock in Europe now

They are well and truly NLA which seems daft for what is a Type 1 part

The burrs arrived today so the last bit of port work can be sorted, I couldn't quite reach round into the exhaust ports to remove all the snots from either end...

[silverbullet]

Some further inlet valve mods.
Turned about 1mm off the head face to get a nice crisp corner (helps to reduce backflow and keep inlet charge in the cylinder) but with a tiny corner break (sharp corners go incandescent...)
Seats are now ~1.5mm inlet, 2.5 exhaust, not the dirty great things they start out with.

Still waiting for my ring gapper...

PS the valves from AMC seem to be very good quality: chrome stems and the heads were tough as **** to turn. The swarf glowed red even with carbide...

[PetenAli]

Love the attention to detail Ian. This is stuff most engine builders would never even think about.

[silverbullet]

Its all just detail work to well established principles, I posted this pdf download link in Tech/Modified a while ago, originally written by A.Graham Bell, the authority on all engine tuning:
http://nocoastmotorsports.net/Manuals/M ... Stroke.pdf

[Titus A Duxass]

Its all just detail work to well established principles, I posted this pdf download link in Tech/Modified a while ago, originally written by A.Graham Bell, the authority on all engine tuning:
http://nocoastmotorsports.net/Manuals/M ... Stroke.pdf

Linkynoworky!

[silverbullet]

You are right Paul, its gone

"Four stroke performance tuning" by A.Graham Bell

Now in its fourth edition.

[Titus A Duxass]

It's available if you google it.

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A little more detail work. The AMC heads seem prone to having a bit of a post-machining ridge around the valve seats, quite pronounced in the case of the exhausts.
Not great for exhaust flow!
A quick bit of work with a 15 degree hand valve seating tool and it's gone:

[silverbullet]

You know what this means:

Rings gapped (tedious) and the gaps oriented (agonizing, looked to the samba in the end) then got them fitted for the last time:

Pete you have an email for the last bits needed for me to finish up;)

[PetenAli]

Ian - you have an e mail in response. On it all!!