Marcus' Corvair conversion, 914-C6 Options

[r3dplanet]

Not much happening today. I spent a good hour hashing things out with my mechanic. I also hoping to get the ball rolling with American-pi about specialty machine work for the roller rockers and 3.1 conversion. I also started a thread over at corvaircenter.com asking about engine specifics. It's lively and informative. And comes complete with a troll.

http://corvaircenter.com/phorum/read.php?1,633330

Today I cleaned the crap out of the pushrod tubes, but I still plan to soda blast them and powder coat them.



It was super nice out this evening so I pulled out the Easy-Off and the power sprayer and hosed down the engine cases. They're going to the machine shop tomorrow. Here's the before and after shots. Remember, this is just a once-over to make it easier for the machine shop.

[rick_cv]

Who are you using for a machine shop? Dan Hall's still open?

[relentless]

Well Marcus, Dr. Evil says I shouldn't comment or offer advice as gospel, even when I put a (?) question mark after what I recall we did when building my engine, and mention it's been over three decades since the work was done. So if you want me to no longer comment or make suggestions I will gladly abide by your decision. I make no representation as to my experience being "gospel."

Maybe you would at least let me post a picture out here how the idler pulley can be *spring mounted* since D. Evil said it couldn't be done! (IMG:style_emoticons/default/lol-2.gif) I found it interesting that someone else also had problems with the reverse rotation belt pulley; something Terry said was probably due to the factory designing the engine to track the belt under load in the original direction.

[Dr Evil]

Last I saw Ray Sedman (sp) was doing the 3.1 with good street credit, but not cheap. There are a few that do the service, but search the web for references. I had mine done in Harrisburg by a very competent shop that does anything, so it is possible to have a local do it if they are smart (IMG:style_emoticons/default/smile.gif)

[Dr Evil]

Well Marcus, Dr. Evil says I shouldn't comment or offer advice as gospel, even when I put a (?) question mark after what I recall we did when building my engine, and mention it's been over three decades since the work was done. So if you want me to no longer comment or make suggestions I will gladly abide by your decision. I make no representation as to my experience being "gospel."

Maybe you would at least let me post a picture out here how the idler pulley can be *spring mounted* since D. Evil said it couldn't be done! (IMG:style_emoticons/default/lol-2.gif) I found it interesting that someone else also had problems with the reverse rotation belt pulley; something Terry said was probably due to the factory designing the engine to track the belt under load in the original direction.

Please do post a pic. I didnt say it couldnt be done, I asked why. The original design does not necessitate a spring and make no provision for one.

As for offering your recollections on corvair engines, you only put one (?) in one of your posts, but you have posted plenty of incorrect info. My only aim is to keep info factual and accurate, not to belittle. I do not want you to leave, just check your facts. All the stuff you are posting about may apply to early vair, but not the late model, 2.7, 110 or 140hp blocks. Having built up one far more recently than 3o years ago, and modifying it as Marcus desires plus some, and researching them, it get tiring when I have to post corrections to misinformation posted in here. The vair may have the most misunderstood of all engines with lots of BS out there. See the comment about "rubber main bearings". Yes, there was a person that both posted that they used rubber main bearings AND believed it about 10 years ago when I first started into vair engines.

Marcus, there is a guy in Santee, CA named Star Cooke who knows these engines really well. He costs money and is arrogant, but if you want something done right he is an option. I have a set of his heads converted for weber 3A carbs.

[r3dplanet]

I want to tell everyone that this is my favorite automotive forum. We keep it technical and rarely do threads devolve into shouting matches. That's pretty much the norm for the classic Chrysler forums I belong to. I don't even post there anymore. Even my thread over at corvair central was accosted within minutes by a single assclown. One of the things I love about 914world (and BMWMOA) is how we manage to keep it clean, providing a sandbox for whomever to sling whatever. Compared to other forums I belong this, this place is an oasis. For example, when conversions are brought up nobody starts a flamewar about who's the idiot. Any conversion - Wankel, Subaru, SBC, etc., is going to be in some minor way controversial. For my own, I think it's low stakes. One day I'll build up a race car and throw the Corvair engine into it. Short story long, I welcome both past and current experiences with those who are Corvair knowledgeable (Relentless) as well as peer review (Dr. Evil). That is the path to factual knowledge. Ultimately the 914 attracts a certain crowd, and they are efficiency-loving gearheads with panache and good attitudes. So, hooray for us.

So far I found a few surprising items in this adventure: Corvair forum "experts" bicker a great deal. There has been so much time and so much development over the years that trying to find the one right way to accomplish any specific task is immediately grounds for argument. Sorting out what's right for me has taken far more time than I had expected. For example, with rockers. There are a myriad of ways to do this and it doesn't help that GM doesn't make them anymore. So there are dozen solutions for replacement, each of which has it's own believers who think the others are stupid. I mean, seriously, rockers.

Another surprising item is there are very, very few washers as far as fasteners go. I'm used to finding lock washers everywhere I look. On this engine I've found only a few. The nuts all seem to be nuts + flange to make a ... nutwasher.

As far as machine work goes: the case prep, crank regrind/polish, balancing of rods, flywheel, etc., is all done by my friend and machinist Gary who's a super genius.

For the specialty stuff like the head, rod, and case work for the 3.1 conversion is (hopefully) going to be done by American-pi. Their work appears stellar and I think the most economical way to go.

Dr. Evil, you hit the nail about Star Cooke. I'm buying my 140 heads from him. Expensive, but absolutely rebuilt correctly by a guy with an excellent reputation and spends his days doing this exact work. It's worth the money for the piece of mind.

[Dr Evil]

I can not seem to stick around on other forums. This one takes what little time and attention I have and I like it and the people so much. (IMG:style_emoticons/default/smile.gif) I have met probably 1000 of the members her all over the country and in Canada (they count, too). You have a great attitude, Marcus.

The one thing that I found good fighting over was how to bore the case. Sedman has the "actual blueprints" and bores the case where the registers where supposed to be, not based on where they are. I did not bother with this and just had them bored. My fuel systems have been the only problems as I continue to experiment.

Have you seen Mark Langford's aircraft page with his 3.1 conversion? Lots of great info there. Also, there are good threads here with links.

[andys]

I think it was one of the HP book series on "How to Hot Rod the Corvair" that I bought when we ran SCTA (dry lakes) out at El Mirage in the late 60's (ran a 180 Corsa in F/Supercharged). Wife recently complained about my library (catch-all) so durring my clean up, I think I threw it out. I hung on to that book for 40+ years.

Andys

[JRust]

As far as machine work goes: the case prep, crank regrind/polish, balancing of rods, flywheel, etc., is all done by my friend and machinist Gary who's a super genius.

For the specialty stuff like the head, rod, and case work for the 3.1 conversion is (hopefully) going to be done by American-pi. Their work appears stellar and I think the most economical way to go.

Dr. Evil, you hit the nail about Star Cooke. I'm buying my 140 heads from him. Expensive, but absolutely rebuilt correctly by a guy with an excellent reputation and spends his days doing this exact work. It's worth the money for the piece of mind.

Man I need to pick up another motor. Maybe I can do my stuff at the same time & we can get a discount (IMG:style_emoticons/default/confused24.gif) Much easier on a machine shop to do 2 of the same right?

[r3dplanet]

Wait, what? What's wrong with your motor?

I know a couple of banjo-playing brothers with a domineering dead father who could probably make you a deal. Just bring a pistol, give GPS directions to your loved ones, and bring some friends. Or it will be more like Kalifornia than Deliverance.

You bring up a point that I should probably have made earlier. I know that my project won't be inexpensive. But luckily the nature of the work is that I can pay as I go. I like that. I think that a properly stock 140 with good head work would be more than enough power for the 914. I'm going a little nuts with my engine (a) because I want to see where this goes and (b) I'm secretly trying to show that even with all of the big modifications this motor will get, it can still be done for about 1/3 of the cost of the Porsche six. I think the -6 is the coolest motor (except that POLO motor). But absurdly expensive. I'm showing an alternative. I also have a sneaking suspicion that for what I spent on my motor, it will be about the same as a souped up Type-4. Last, for what I'm spending on the monster 3.1 liter, I could have spent less than half and built up a stock 140. That's where the smart money is.

So - yes! Maybe we can double up on some machine work. We also need to develop a nice cradle for the engine.

I've already learned that if I were doing this again I wouldn't even bother with a donor motor. At the end of the day I'm only using the major pieces from the donor, and I'm sure I could have found cleaned and prepped bits for about what I spent ($100) on the motor.

As of today, here's the bucket of reusable parts:



Aside from the engine case and crankshaft, this bin includes the top cover, front cover, oil filter assembly, fan (and bearing), and pushrod tubes. Everything else is scrap.

As far as machine work goes: the case prep, crank regrind/polish, balancing of rods, flywheel, etc., is all done by my friend and machinist Gary who's a super genius.

For the specialty stuff like the head, rod, and case work for the 3.1 conversion is (hopefully) going to be done by American-pi. Their work appears stellar and I think the most economical way to go.

Dr. Evil, you hit the nail about Star Cooke. I'm buying my 140 heads from him. Expensive, but absolutely rebuilt correctly by a guy with an excellent reputation and spends his days doing this exact work. It's worth the money for the piece of mind.

Man I need to pick up another motor. Maybe I can do my stuff at the same time & we can get a discount (IMG:style_emoticons/default/confused24.gif) Much easier on a machine shop to do 2 of the same right?

[r3dplanet]

Ah, I found an out-of-print copy and it's on the way. Good catch!

I think it was one of the HP book series on "How to Hot Rod the Corvair" that I bought when we ran SCTA (dry lakes) out at El Mirage in the late 60's (ran a 180 Corsa in F/Supercharged). Wife recently complained about my library (catch-all) so durring my clean up, I think I threw it out. I hung on to that book for 40+ years.

Andys

[r3dplanet]

Some minor progress happening today. The machinist cleaned and bead-blasted all of the aluminum and magnesium parts and they look super.



He ran the case halves through the parts washer but we opted not to bead blast the case hemispheres until we know for certain that the case tests out okay. He inspected for cracks and deformations and none were found. So I cleaned and very lightly polished the cam and crank journals to get some clean readings. I'm also having the old cylinders cleaned up so I can run a head stud torque test and then sell them off.



The engine build process requires bolting up and then disassembling the case hemispheres many times, and this is the first. Using the old case studs I torqued them ogether and made sure all was even:



Then I used a pair of dial bore gauges to see how much variance there was in terms of side-to-side distance and out-of-roundness. Since the cam rolls directly in the journals without the aid of bearings, I thought for sure these would be way off. It turns out that there was less than half a thousandth deformation, which is right in spec. I'm a touch amazed by that. The crank journals also measured no more than a half thousandth, so I'm super lucky. For a moment I thought about having the case insides lapped, but figuring that it might throw off the crank bearing clearance I'll just clean them with a razor blade and leave them be.





Next up is the head stud torque test. If the case can pass that, then it's a good donor. More on that when the cylinders return.

[andys]

Looking good!
Comming from 30+ years of managing protoype and tool shops in the medical industry, tell me you didn't set your bore gage using calipers.

Andys

[r3dplanet]

Nope. I used a micrometer. The calipers were just to get an idea of the diameter of the journals so I could use the correct anvil.

Thanks for keeping check on me!

[andys]

Nope. I used a micrometer. The calipers were just to get an idea of the diameter of the journals so I could use the correct anvil.

Thanks for keeping check on me!

Good man!!!!!

Andys

[Dr Evil]

(IMG:style_emoticons/default/smile.gif) This thread pleases me (IMG:style_emoticons/default/smile.gif)

[injunmort]

I don't mean to be obtuse, and I certainly don't know corvair engines but you said the cam runs on the machined aluminum surface of the case without a bearing. did I understand that correctly?

[r3dplanet]

Correct. I have no idea why. Apparently GM engineers didn't think cam bearings were necessary - which seems a bit unsettling. But after finding virtually no wear with the bore gauge, I've come to think that it isn't a huge deal. Apparently, my low wear is near identical to other Corvair engine rebuilds in that the cam journals just don't seem to wear down. One reason I think is that the cam sits so low in the engine that it's constantly flooded with oil. But like you, I certainly raised an eyebrow when I discovered this. Apparently this design decision has been justified over the decades.

I don't mean to be obtuse, and I certainly don't know corvair engines but you said the cam runs on the machined aluminum surface of the case without a bearing. did I understand that correctly?

[gf4c]

Hello Marcus

you wrote: He ran the case halves through the parts washer but we opted not to bead blast the case hemispheres until we know for certain that the case tests out okay.

I have seen several Corvair engines ruined by bead blasting the engine case. No matter how clean you think you might have it, there are often bits of glass beads hiding and waiting to kiss your crank (IMG:style_emoticons/default/mad.gif) You can get the case very clean with some simple green and some elbow grease, lots of hot soapy water works wonders.

you also wrote: I'm also having the old cylinders cleaned up so I can run a head stud torque test and then sell them off.

You can also run a head stud torque test with an appropriate length (and diameter) of tubing or pipe. Just slip the tubing/pipe over the head stud, add nut and torque away.

Also, Lon Wall at Corvair Underground is buying late model cylinders, he is not far from your location.

Marty

[r3dplanet]

Thanks for the input, Marty. I appreciate it. Marty .. as in Marty Scarr? If so, I'm honored!

I had considered just using a tube for the head stud torque test but thought that somehow using an actual cylinder would be more realistic. I guess it technically doesn't matter. Also, since I wrote about scrapping the cylinders I've decided that have them cleaned and prepped to sell them instead of scrapping them.

The cleaning of the case halves is a vexing issue. I've heard some say never to bead blast it as you suggest. I've heard other authorities say not to worry about it. My issue is that at this point I just can't get it any cleaner with Simple Green, kerosene, Biokleen, Easy Off, or anything else I've tried. There's a metal dipper in town that uses electrolysis but that's destructive for aluminum (ask me how I know). I'd be open to other suggestions.

-m.