Tear Down and Reassemble Unstarted 1.7 built to 2270, 1.7 to 2270 Unstarted 10 Year Old Build Options

[Robroe]

Moved from topic of first start of 10 year old build to tear down, inspect and reassemble. The 10 year old build is from a 73 1.7 to a 2270. Stroked to 78 mm and 96 mm cylinder diameter. Heads are Ham/RAT with 36 mm exhaust and 44 mm intake. Both are nicely ported.

Have torn it down to the case and checking crank end play before I split the case and pull the cam and crank. So far, everything is new and looks in good order. I'm concerned about oil passages being blocked with old assembly lube so a complete tear down and reassemble is happening. Discovered stacked cylinder spacers (4) totaling .150". So looking to replace those with single spacers. So far I can only find .160" spacers from type 4 store and may just use them as impact on compression appears minimal. Was shocked to discover crank end play is .450"! Sure glad I didn't try to start this thing. Will check again in the morning to make sure I'm checking it correctly, but I'm doing the same thing on the videos such as Ian Carrs YouTube engine builds so pretty sure I'm checking it correctly. Now to figure out what to do about that huge end play.

Any thoughts about what to watch out for?

[Superhawk996]

You’ve got to dig into this - agree with Ninja that you want to do it with a flywheel mocked up to the crank.

But let’s just do some assumptions.

If you really have .058; you’re not going to get there. Thickest shims is .38mm (0.015”)
Since there are to be 3 shims (no more, no less) that only pulls out 0.045” of end play. Not good enough.

Possibilities:
crank machined wrong.
Bearing thrust surface too thin.
[edit add] Flywheel machined incorrectly

With respect to the crank: be sure the journal throws - counterweights aren’t hitting case when the crank is fully thrusted one way or another.

Off the top of my head I don’t know if there are detailed enough dimensions in the factory manual to inspect the crank and figure out what may be mismatching. I’d need to dig on that.

There are known issues with aftermarket 911 bearings that I’ve lived myself and which are well documented on the bird site. Is it possible that these 914 bearings are out of spec? I wouldn’t rule that out. There are several brands of 914 bearings out there.

It appears your bearings are marked as standard size which is good. I’d order another set of bearings and see. Preferably NOS like Mahle or KolbenSchmitt but those are getting rare as hens teeth and pricey. Might just try a set of sliver line bearings just to see what you get and if it helps.

If all that fails and nothing is hitting the case, all hope isn’t lost. You could have a shim machined but it won’t be cheap.

With respect to the flywheel. Is it new? If used - has it been remachined? There are some dimensional drawings of flywheels available - I’ll see if I can dig it up

Do some more mock up with the flywheel and measure off the crank nose and let’s see what you end up with.