Engine case machining - type4 / 914

[smallspeed]

I’ve come across a weird situation with my type 4 case in that one of the bearing “saddles” appears to be undersize!
Only by 0.2mm but enough to prevent the standard size bearing seating in the case by way too much just to tap it down - it would definitely pinch the crank

It’s bang on size side-to-side between the two case halves but top to bottom (effectively along the split line) it’s small

Firstly - has anyone seen this or heard of it before? It’s not ovalled as such otherwise I’d expect the other direction to be oversize, but it is slightly oval..

Secondly - who do people recommend for line boring? I’m fine with getting this done and going up a bearing size if that’s what’s required because otherwise the case seems pretty good. I can only find people doing type 1’s on google though..

Hope someone can help

Ben

[Bruce M]

Did the case already have a bearing in it? Bearing quality for new parts has been very variable (even for branded parts) so check the bearing isn’t off although I suspect you’ve checked that out already. Perhaps it’s a symptom of over torqued case bolts perhaps combined with overheating.

Another place to check is across the cylinder bores in the case. Apparently they can sink in the middle enough to cause a leak at the heads due to the cylinder being tipped sideways a fraction of a mm. Weird, but that seems to be a thing.

Stateside Tuning is the obvious trustworthy place to get it checked but I’m sure there are other options.

[smallspeed]

I think possibly you’re right - I’ve done a lot more measuring and inspecting this evening and it appears the edges of the case at the bearing saddle (not sure if that’s the right word) have effectively mushroomed inwards towards the bearing both sides, leading to it looking like the top of a heart, top and bottom at the split line.
Otherwise the case appears bang on so hopefully it’s salvageable, especially since I spent ages cleaning it
I will measure the tops of the case halves and check the parallelism of the barrels tomorrow - thanks for the tip-off!

Ben

PS - On the three times I’ve spoken to stateside about doing any machining he’s basically said “used = scrap” and tried to sell me new stuff. Nothing against the guy; I have no actual experience using him to do anything, and he gets a lot of recommendations. I just get the feeling he isn’t interested in doing bits of work for people, and is more interested in selling turn key engines.

[middlefour1]

Worth giving Angus a call at Greatworth Classics.

[neilbardsley]

Worth giving Angus a call at Greatworth Classics.

Angus will advise but I think he uses state side for his matching work. That may of changes not he has an ex redtek machinist

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[camperco]

We do have our own in-house machine shop and machinist Will joined us from Redtek last year. Stateside do our VW case align boring at present and of course crankshaft grinding goes out too but everything else is done in-house. Its not that we think we can machine any better than the established experts around here its that we want to be in control of our own deadlines.

We would be happy to have a look at your case if you want to call by with it or send in some photos.