TheSamba.com :: View topic - Engine rebuild question - is it a nightmare to re-assemble

Wed Oct 08, 2008 3:28 pm

I am the stage of myWesty restoration where I am about to rebuild the motor. I have read through many of the threads on this site and feel confident that this I can handle this my self. I have re-built other engines in the past but never a water boxer.

The question I have is, today after talking to a local mechanic that has extensive experience repairing VW's, he put up a big caution flag when it comes to putting the engine back together. Something about the cylinder sleeves not lining up properly when the heads are put back on and that there is a 50:50 chance it will be done wrong and the the engine will leak.

I can't recall any cautions here about it. I have the crank, rod and cam thing figured out. I will re-use the pistons and sleeves if in tolerance and if not will only go with German replacements. I have orignal heads and will have them magnefluxed to check for cracks. Either recondition the valves or replace with TRW. Will be putting in a new oil pump and new lifters.

Am I missing anything that is going to bite me in the ass later.

BTW, my first choice would be to send it to Boston Bob but he is too far away and freight will kill me.

Wed Oct 08, 2008 5:42 pm

kobylan wrote: The question I have is, today after talking to a local mechanic that has extensive experience repairing VW's, he put up a big caution flag when it comes to putting the engine back together. Something about the cylinder sleeves not lining up properly when the heads are put back on and that there is a 50:50 chance it will be done wrong and the the engine will leak.

He doesn't have a lot of experience with wasser engine, that is for sure.

Sleeve will sit nicely a the bottom end, the one thing people don't understand is to tight the pushrod side of the head first until this side of the head touch the outer head gasket, use the 2 center stud only. After, follow the Bentley for the tight sequence.

When putting the head on make sure the head gasket (2 round one) are well in place, same thing for the green O-Ring on top of each sleeve.

Now, PLEASE, trow those heads in the garbage! No mater what they look like.
Buy some AMC and get some German valves.

Ben

Wed Oct 08, 2008 6:39 pm

ftp2leta wrote: kobylan wrote: The question I have is, today after talking to a local mechanic that has extensive experience repairing VW's, he put up a big caution flag when it comes to putting the engine back together. Something about the cylinder sleeves not lining up properly when the heads are put back on and that there is a 50:50 chance it will be done wrong and the the engine will leak.

He doesn't have a lot of experience with wasser engine, that is for sure.

Sleeve will sit nicely a the bottom end, the one thing people don't understand is to tight the pushrod side of the head first until this side of the head touch the outer head gasket, use the 2 center stud only. After, follow the Bentley for the tight sequence.

When putting the head on make sure the head gasket (2 round one) are well in place, same thing for the green O-Ring on top of each sleeve.

Now, PLEASE, trow those heads in the garbage! No mater what they look like.
Buy some AMC and get some German valves.

Ben
Shazam___well spoken

But then we have done a few............

Wed Oct 08, 2008 6:51 pm

I second Mr. Ben on the heads; don't waste your time with the VW ones. Get some new AMC's, put in TRW exhausts, grind the keepers so there is a tiny gap between them when they're clasped on the stem, and you'll get many many more miles out of the rebuild.
Besides,
Quote: I have orignal heads and will have them magnefluxed to check for cracks
I didn't know you could magnaflux aluminum.

Getting everything to line up when you slip the heads on is a bit complicated, but not much moreso than an aircooled.

There are metal cylinder sealing rings that slip in the heads; the old trick on AC's was to grease the rings and stick them into the heads so they don't fall out. That same trick works here.

The green o-rings that go around the top of the cylinder can get pinched and sliced if you torque the head down onto the cylinders at too much of an angle, and having to compress the pushrod tubes while you draw the head down is what makes the alignment a little tricky. It's not that hard, really, many not-too-experienced wrenches have done this job successfully laying on their backs in the dirt. But I have a trick to make it much easier to get the jugs started straight into the heads without worrying about pinching those o-rings.

When I install the pistons/jugs, I push the jug down just far enough to be started in the case spigot, but don't push it all the way home yet. The rings hold a jug wherever you put it. Once the jugs have begun entering the spigots in the case, they will self-align and there's no way they won't end up seated flat. So leave both jugs on one side up about 3/4" before you put the head on. Then when you slide the head on, you can slip the jugs right into the head spigot at right about the same time as you're lining up each pushrod tube, so the jugs are already stuck in the head and you don't have to watch their alignment while you use the lower head nuts to draw down and compress the tubes. Makes the whole thing a lot easier and surer.

Oh, and use sealant on both sides of the water jacket seal, not just the outer face as shown in the book. Put sealant first on the end-face of the water jacket, fit up the seal, and then apply sealant as shown. Only use a little sealant.

Wed Oct 08, 2008 7:06 pm

Reusing piston/cylinders, make sure you keep them matched. The other guys here who know much more than me will tell you whether or not that is correct.

I just rebuilt my motor and I've never rebuilt a waterboxer before. It runs great.

Oh yeah, use a beam style torque wrench not a click style to torque the head bolts!

Wed Oct 08, 2008 8:27 pm

Here a pic just before closing everything.
The valves are the stock AMC one, customer was not ready to pay for extra work / valves....

Ben

Wed Oct 08, 2008 9:20 pm

Thanks for all of the feedback.

My oops on the magnaflux. Wasn't too familiar with the process, thanks to Wikepedia I am now!!

As mentioned I plan on getting a lower end kit from Stamos. I am in the Vancouver, B.C. area and have not heard of anybody with the quality that Stamos does. Any suggestions

I was hoping to save a couple of bucks on the heads. I read one post that if the old ones were not cracked to save them. I am definitely leaning towards the AMC's. A lot of work on the engine to not do it right.

What is the concensus on the the new AMC's? Are the exhaust valves still an issue? Four exhaust valves is a pretty small price to pay if I have to swap them compared to iminent failure. I would assume that all that is needed is to lap the new exhaust valves (besides the keepers)? Any issue with intakes.

Wed Oct 08, 2008 9:56 pm

I run with the intakes. They only problems I've seen reported on them was due to the bad fit of the keepers, not the valves. Intakes run very cool. Gotta do the exhausts, though, or face a burn at about 30k, typically.

New AMC's have a very good seat-cut so no lapping should be needed; haven't got any that needed it yet. Just blue the valves to check.

Nice to get in with a burr and blend in the seats and knock down the flashing in the ports.

Wed Oct 08, 2008 10:07 pm

Thanks Tencent.

I haven't "blued" valves before. What is that?

Wed Oct 08, 2008 10:27 pm

Get a little tube of Prussian Blue. It's a deep blue kind of gel, almost, that you coat mating surfaces with and work them together. The blue lets you see where they make contact. If you see good contact all around each valve in its seat, no lapping is needed. With modern hardened materials, it's better not to lap if it's not needed, because it opens up the hardened surfaces.

Wed Oct 08, 2008 10:33 pm

Thanks.

Push rod tubes -- new or re-use?

Wed Oct 08, 2008 10:42 pm

Clean 'em up, stretch 'em out. There's a spec in the book for how long to stretch them to, but they don't even need to be that long to make good sealing pressure.

Use the tube seals dry, very clean and dry on the sealing spigots where they seat.

If you want to make the top end assembly really easy, get a set of expandable pushrod tubes. Then you cans slip them in after the heads are on, and they make it easy to service lifters if ever needed. I use the Jaycee ones at CB, reversed. Use the search.