My newbie obsessive questions about VW repair

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Aviacs

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Realized i was sort of hi-jacking other posts with my questions and there are sure to be many more.
Some of the following might be a repeat of other posts, but trying to consolidate in one place.
I have been reading Bob Hoover off and on for a few years, have the Aero-Vee manual, and most of the GP manual/reference materials. Have topped & maintained a few Continentals including a GO300 i used to own, and various 4 cyl. Continentals since. Misspent youth elbow deep in MC's & a few Brit sports cars 40 - 50 yrs ago. I'm a capable manual machinist. OTOH, VW engines are completely new to me.

Engine in question is a GP 2276 installed new sept 2013 & flown 35 hrs until June of 2017. EMPI heads. Airplane is a Sonerai 2.

Basically, i don't know what is normal for the engine, and what the tolerances and limits are for inspection.

I borescoped the cylinders and saw more rust than i was comfortable with, esp around the exhaust valve seats. So pulled the worst looking head. Most everyone else who has seen it said " You should have just run it & changed the oil, it would clean itself out."

On the bench the valve keeper lands were swaged out to the extent the valves would not slide through the guides until i used a small last-cut file to dress them all around. The intakes are essentially straight/cylindrical and there is little deviation in the guide ID's. The Manley Stainless exhaust stems are barrel shaped. "Good one" is about .0025 under at each end of travel range. Worst is a little over .003". Valve stems are .310 +/- a couple tenths in the centers, as are the intake stems "all over". Ex guide ID's are .025" & .030" over valve stem size at each end of the guide. The wear in the guides is slightly oval.

Inspecting this head compelled me to go back and pull the other, which i will dis-assemble and inspect today.

My assumption is that the exhaust guides and valves should be replaced & recut seats to match?

Should the intake valves be replaced "anyway" ?

Last night while removing the cyl 1 & 2 side head, most of the studs unscrewed. They are 8MM and the nuts are rusted or galled to the top thread area to the extent i could not hold the studs from spinning in a flat-face machine vise on one of the hangar mills, albeit it is a cheapo vise. (Not an angloc). I left them with penetrating oil and will clean up later.

Should i buy a new stud set? Despite my mention of rust, the studs are mostly clean, the rust is under the threads. My inclination is to just buy a new set, but maybe that is dumb? If i clean the studs up, can i just use new grade 8 nuts from the local jobber? How about new, cut down (OD), grade 8 washers?

I'm trying to put together an order list and get everything at once, though there's always "just one more" item found later, of course.

For a 2276 av-conversion VW, what should the cold, dry, clearance between stem and guide be, when new exhaust guides and valves are installed?

People on several forums have generously linked various online sources for reference which are much appreciated, and utilized.
OTOH, not always clear how applicable to av use some of the specs might be. Is there a good manual, like a Continental OH manual, that sets all the tolerances, limits and inspection procedures out? With focus on Av application?

Thanks!
smt
 
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karmarepair

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There are are lot of questions here, and I'm just going to address a few: try and find "Without Guesswork" AKA "Technical Data For Workshop Use". It has tolerances and wear limits for many things on the whole car, but includes the engine. Unfortunately, I don't know where I got my copy, a modern reprint - I think from a specialist tool maker in Nebraska that is no longer in business. VW stopped issuing them in 1970 apparently. The Bentley workshop manuals MAY have this same information. It looks like there is a scan here Obsolete Air-Cooled Documentation Project -- Without Guesswork 1969

WRT to the stem to valve clearance, Bob talks about the Wiggle Test. Basically the stem should run freely in the guide, but when new, without perceptible "wiggle" side to side. But if you want numbers, from the aforementioned, exhaust guide diameter new, stock ID should be 8.00 to 8.02 mm, wear limit is 8.06 mm. Stem diameter new 7.91 - 7.92, wear limit 7.87, out of round max 0.01 mm.

It sounds to me like your heads have been running way too hot, softening the valves. Your baffling needs to go all the way out to the edge of the heads, and you need enough exit area on the cowl and probably a lip at the forward edge of the opening to create a low pressure area to pull cooling air through the heads. Look at the CURRENT baffling on a SONEX for an example.

For parts, buy everything from VW Parts - Aircooled VW Parts Catalog at Aircooled.Net and nobody else, exception being aviation specific stuff.
 

Vigilant1

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I'm among the least experienced here re: VW engine stuff, but I'd suggest taking a look at the price of new heads for your application. They come with new valves, seats, guides etc, etc and no cracks, never been run hot, spark plugs holes have never been stripped, etc. Even after paying to have a second set of holes drilled and tapped for new plugs, you may be surprised at the price. Then you'll at least be starting with a clean sheet/known quantity.

GPAS can sell them to you. Also, I've been tempted by these Panchito heads just because of the promised improved cooling, more "meat" between the valves etc, but I have no direct experience with them.
Panchito 044 Dual Port Cylinder Head (88TW/90.5/92mm or 94mm Bore), 40 X 35mm Valves, per EACH - Volkswagen Aircooled.Net VW Parts


OTOH, doing repairs on your existing heads will give you new skills and maybe save some money.
 
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Aviacs

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Karma- Thank you for the detailed response, this is great!
Going to bury myself in the _Without Guesswork _ literature.

Trying to put together an order at aircooled.net and found most of the gaskets, seals, new head nuts and washers, & new valve keepers. Also noticed a couple things:
1.) they don't have some things, like the black chrome pushrod tubes that Scat sells. Many other things are "out of stock"
2.) I made a deck height checking tool last week, so was curious to see that Scat makes one for 36.95 to see how we differ. Just now noticed 49.95 for the exact same thing at aircooled.net
3.) Sent an email, waiting to hear response: These valves are not specified in or ex. Type 1 Stainless Steel Valves, Choose Size, Set of 4 - Aircooled.Net VW Parts Is the implication they are either? Scat sells in and ex specific stainless valves with hardened tips and hard chrome barrels. So now i have to make a choice. :rolleyes:

Significant parts on aircooled.net are specifically listed as Scat.

I respect that you must have spent and wasted a lot of time and hopefully not too many bad parts to arrive at your "& no one else" dedication. But have to ask, is it price consciousness, or too many experiences with poor quality at other vendors?

4.) aircooled.net lists premium guides made of aluminum silicon bronze Racing Intake Valve Guides, Type 1 Based Engines, Set of 4 - Aircooled.Net VW Parts but describes them as for intake. It would seem the exhaust needs them more? I sent an email asking if it would be a bad idea for exhaust. It would not make sense to set up the turret lathe to make the standard guides at the price listed for the regular silicone bronze, but might for the more expensive version if it is "better". If they respond, i'll see if they will specify which alloy they use.

While i was typing, this response also came in :(

Thank you for your inquiry. A representative will respond specifically to your email as soon as they are able (we are short-staffed and email response times can be very slow - sorry!)

THIS IS AN AUTOREPLY / NOTICE

IMPORTANT SERVICE ANNOUNCEMENT
AIRCOOLED.NET IS CURRENTLY DOWNSIZING.
After 23 years serving the aircooled VW community, the events of the past 2 years have caused us to have to reconfigure how we operate our company. Please know how much we have appreciated, and continue to appreciate all of your patience and support of our efforts to continue serving the aircooled VW community!

Through this process (which we expect will take 2-3 months), we are continuing to attempt to fulfill as many backorders and new order requests as our staff and access to inventory will allow.

If you have a backorder open and wish to cancel rather than continue waiting, you can email to cancel un-shipped items at any time as long as they are not special order or made/machined-to-order.

We continue to endeavor to answer email inquiries as best we can. Please rest assured that we are still fulfilling and shipping previously submitted and/or delayed order requests (as product availability allows), as well as being wholly committed to resolving any other issues that may arise.

We sincerely appreciate your understanding and support.

Sincerely,
The Aircooled.Net Customer Care and Order Fulfillment Crew

Thanks for all the help so far, just these leads mean a little bit of progress, with a better vision of direction to press forward.

smt

PS: my wife is kind of happy-
I mentioned that since there is still too much missing info to order parts, and they will not come for almost a week even if ordered over the weekend, i might have to go back to work on the house to get over the frustration. :)
 
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karmarepair

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John at Aircooled.Net has been VERY helpful with advice and will NOT sell junk. Everything he sells he's personally vetted. I'm not sure what to make of this notice. I'll have to go to Shop Talk Forums or The Samba (two good forums, like this one, for all things Air Cooled VW) to see what's what.

The best pushrod tubes are the thin steel ones, painted or powder coated black so they dissipate heat better. Chrome keeps heat in. Same with valve covers, although the stock ones don't work with other than stock rockers and cams without modification.

Aftermarket heads for a long time ranged from Absolute to Semi junk, including the CB Performance 044 heads on my Aerovee (I've cleaned them up to my satisfaction). I ordered a complete head from Sonex, which is based on an EMPI casting from China, and they are the best I've ever seen.

Do you have either the Bentley WORKSHOP manual or Tom Wilson's "How to Rebuild Your Air Cooled Volkswagen Engine"? I just pulled my copy of the second one off the shelf, it has a long discussion on replacing valve guides. Oversize (on the OD) guides are used when the head casting gets beat up getting the old guides out. The Wilson book also looks like it has sprinkled through it most of the same information as the Unicorn "Without Guesswork" guides.

The Idiot Book ("How to Keep Your Volkswagen Alive, a Manual of Step By Step Procedures for the Compleat Idiot") has info on homebuilt special tools for things like checking deck height in the basic but good section in the later editions on building high performance engines, but the Tom Wilson book is better on the details, but he only covers stockers.

Reviewing your valve dimensions, given that the allowable clearance is stem to guide clearance is 0.0025" to 0.0035", it looks like SOMETHING Must Be Done. Again, heat kills heads. But there is another common source of valve system wear and that is spring pressure. If you have double springs on your engine, chuck them and get either stock or high performance single springs at most. At the RPMs we run, we don't need a ton of spring pressure to avoid valve float, even with a high lift cam. The excess spring pressure just wears everything out. And do as many of the HVX mods as you can to get more cool oil to the valve stems.
 

karmarepair

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And WRT to Aircooled.net, I found this recent post from someone who orders a lot more than I ever have:

"I tend to spread my ACVW parts purchases between 4 different vendors.
Aircooled.net, CB Performance, AA Pistons and Wolfsburg West.

Never spent a penny at J-Bugs or CIP1.

ACN, is my go to place, for first choice parts purchases.
This is due to their excellent customer service. If there is a delay in delivering parts. I get an email to that effect.
The other three vendors that I support don't let me know if there an issue with my order."


But there was also a post from March of this year from Stephanie at Aircooled.net explaining/apologizing for delays that have HURT their customer service experience.

John and Stephanie may have decided to give up the fight, but I don't see evidence on that on The Samba or Shop Talk Forums.
 

karmarepair

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WRT heads, check out this comparison http://www.cfiamerica.com/images/pdf/Hot_Vws_Type1_Heads.pdf You want to be able to see through the heads around the valves. As you can see, there is a lot of difference. The new EMPI heads (not sure they are pictured here) are very good in this respect. Some of the drag racing heads are nearly solid in this critical area - fine as they are fuel cooled in the 15-20 seconds they run at full power, not so much for us running high BMEP at low RPMs for hours on end. You can CAREFULLY clean up the casting flash on the Less Good heads, to a certain extent, but the MOFOCO heads for one example have fewer, thicker fins than stock, and will NEVER cool as well.
 

Bill-Higdon

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WRT heads, check out this comparison http://www.cfiamerica.com/images/pdf/Hot_Vws_Type1_Heads.pdf You want to be able to see through the heads around the valves. As you can see, there is a lot of difference. The new EMPI heads (not sure they are pictured here) are very good in this respect. Some of the drag racing heads are nearly solid in this critical area - fine as they are fuel cooled in the 15-20 seconds they run at full power, not so much for us running high BMEP at low RPMs for hours on end. You can CAREFULLY clean up the casting flash on the Less Good heads, to a certain extent, but the MOFOCO heads for one example have fewer, thicker fins than stock, and will NEVER cool as well.
The Hapi individual heads were Scat racing heads & had issues with cooling.
 

Aviacs

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I can't believe how much effort you are putting into this, and am grateful.
It's like drinking from a firehose, and loving it! Lots more to digest.

3 quick notes:
The best pushrod tubes are the thin steel ones, painted or powder coated black so they dissipate heat better. Chrome keeps heat in.

I get that concept, misunderstood/assumed "black chrome" left out the nickel layer in favor of something dull.
Apparently it does not - the (shiny) nickel layer is still in there, just a different surface treatment. Thanks for the clarification. I'll get steel and dust it with hi-temp. :) Or at this point probably just scuff and dull the old ones, and paint them. They are in good shape.

The "16 heads comparison" is perfect.
My current EMPI heads are see-through, but i was studying them while starting to clean and wondered how much the passages could be opened. You have provide an answer and guidelines.

John replied to a couple of questions, the stainless valves can indeed be used for either exhaust or intake, just choose dia accordingly. We are still going back and forth on the guides.

smt
 

Aviacs

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Vigilant1-
Panchito heads have been on my radar per mentions here on homebuiltairplanes & further research. I hope to not need heads this time 'round. Heck, the sad part is i still need an AW...... Meaning the intention is to build a solid engine back up & not skimp on the parts that should be changed. But perhaps not quite a "dream" engine until the airplane itself is actually back in the air. I have seen so many dream projects and then health fails and they don't get to enjoy it. Hoping to avoid that bullet, so to speak.

smt
 

Aviacs

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I am curious: with the disturbing presence of corrosion in the top end, what does the steel parts in the bottom end look like?

You & me both! :)

seriously, most who have seen the engine top end said i was an idiot to take it apart.
Due to the worn guides (which are not a corrosion issue) i'm feeling comfortable in the choice.
Nothing inside the oiled parts of the engine shows corrosion.

I initially expected to have the cylinders fall out, and check that way as well as with the borescope.
Since the cylinders are glued in so securely, my plan is to borescope up through the oil screen hole when new gaskets arrive to re-attach it. If that proves unfeasible, i might have to (reluctantly) actually use the cylinder puller i made. Post #205 here: Building a VW Aero-Engine
 

karmarepair

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I'll get steel and dust it with hi-temp.
NOT High Temp. That stuff has a lot of metal salts in it, and it HOLDS heat in.

Just flat black Rustoleum.

I have a junk toaster oven I use to BAKE painted metal parts in after they dry to the touch, cheap, super durable, and will resist the hot oil temperature, and keep the rust away.

Make sure your tubes are long enough; there is a spec on it somewhere (although it's a little fiddly to stretch them if they have gotten smushed), and use the white, Made In Germany seals, or whatever John at AirCooled.net is selling.
 

Aviacs

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went hiking over the weekend, so at my age (69 & still counting, fortunately) recovering. :)

Thanks for the tip re paint.

Since i don't know what material was used for guides, and since all evidence is that initial installation might have been with too much clearance (still reading the no-guess book :) ) I'm dithering on the guide materials.
Most recommend stainless valves, so that is done. Now it's down to guide spec.

Also waiting for melamine blast media from Aircraft Spruce ordered Friday, for later in the week.

Thank you!

smt
 

TFF

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The valve sticking problems are about lead deposits jamming the valve. Lycoming and Continental opened up their clearances to help. That and the 500 hr inspection supposed to keep all copacetic. No guarantee, but that’s how they mitigate it. VWs do come apart more often as the nature of the beast. Unleaded car gas or a blend with 100LL makes these smaller engines happier. Makes 912s happier too.
 
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