mixing case halves

[joescoolcustoms]

This debate kind of reminds me of the old debate about turbos.

"You cannot go over 2.5 to 3 pounds boost on a VW, the carbs will not handel it." Well that myth was proved so wrong wasn't it?

Why not try?
I have not seen one good answer to that question in this debate so far. If Nick wants to do it, so what, still a free country at this point.
_________________
Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[Michael Fischer]

Just slap em together and linebore it. I have seen it done it will be fine.

[miniman82]

Just like driving around without front brakes.
_________________
Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

[joescoolcustoms]

[Jimmy111]

[Michael Fischer]

[Jimmy111]

This guy.

[nsracing]

[Jimmy111]

Nick I dont think anyone is going to do this it they only have a .020 over bore. But if they have a .060 over bore and the case is needed then they might consider it.
That .060 has to be removed and brought down to stock or less. The side to side is not the problem. the up to down dimention is the hard one and requires all the material removal to make round again.

[nsracing]

Actually, you can bore to the same size...whatever it is already.

If the you have a case say bored to 0.040 already, and you have some warping, it can be reflycut along the seams and then re-bore to 0.040 again. Since the old 0.040 size will be undersized after the flycut. This is the only way you can do it.

I do not think you can bring back to standard after it got linebored already.

[Harleyelf]

GEX has indeed done it, but not well. I got an engine from them with a left case half part number starting with a "2" and the right half starting with a "3"; the thing is half bus, half fastback! Larry at GEX swears those things I sent him pictures of are not part numbers and that the stamped numbers at the flywheel cover prove they came on the same car. Said numbers are crystal clear despite being allegedly 45 years old, and are stamped into machined flat surfaces, not the original sand cast surface. How unique! No corrosion at all since 1964!
The engine has never run right and is currently blowing oil drops out the exhaust and pushing lots of oil out of the dipstick tube. The spark plug holes were coated in paint, which is not a bad thing except if you want to believe Larry's claim that it was test run at the factory. I had to chase the threads with a tap before installing the plugs. In short, case halves are married at the factory and will have unnaturally short lives if mixed. On the plus side, the engine has a few thousand miles on it and does not make any lower end noises. Might have worked if I hadn't gotten greedy for displacement and ordered the 1644 pistons. It needs major breathing therapy to handle the air from under the pistons. I'm thinking of putting a PCV in.

[PEPPE]

with mixing of case halves many other areas of the case needs checking/adjustment.

-plane of sump plate
-plane of sealing surface of the oil pump
-mismatched height of cam plug (there is a v machined ring that will not match)
-out of shape hole for flywheel seal (the dual C shape will not much being at different height)
-same for cam, and oil pump hole.
having many cases to choose from, you can select the ones that are more similar in distance between mains and cam tunnels and maybe you will have to correct less things.
using oversize fan pulleys and oversize cam bore bearings will help a lot. (some euro rebuilders do it)
another detail is to use an undersize brass gear for distributor. it is needed for giant sealing surface flycuts. (euro rebuilders do it)

not easy at all. but very little case halver are good candidate for the machining cost and result.

[PEPPE]

oh, and you will have also to redo oversize the centering holes for the up and down centering pins of the case. they will not center on differnent case halves, this will help the rest of the holes centering.
some holes of the studs will need some trimming for ease of sliding of them through the case on new centering pins.

[AJTowers]

Some of the replies in this thread make me LMAO. It sure is easy to tell who is a machinist, or at least has some knowledge, and who is not. I happen to be a machinist and the last time I put my 2275 together I resurfaced the case halves, because they had some fretting from high RPM, and honed the main and cam bores back to standard size. It's not that big of a deal people. Btw, that was 6 or 7 years and several thousand miles ago, still runs good and doesn't leak a bunch of oil or have any of the other problems listed above. It's just machining folks, anything can be done with enough time and money.
_________________
RPM's= Ruins-People's-Motors

[PEPPE]

if it is only very few to correct, ie 0-10mm it will work with no big machining. mains and cam will center tools and correct with honing and oil pump will not have problem due to the fact that oil pump are usually 0.10mm undersize and will install ok. using a silicone/rubber main seal will work the same 0.10mm will not do nothing, just a little more difficult to slide.