Project Berg 1679 rebuild and update with squish!

[Martin S.]

My wife's 65 Bug was repainted last year and now the engine needs attention. I built it in 1999 with all Berg parts and the 88 thick wall PCs and running the stock carb. 75,000 MILES later it was ok still but a lot has changed in motor building since then and I wanted to give it new life with more CR and squish to get better fuel economy and power. It had semi hemi heads with 6.8:1 CR. Upon tear down one head was warped and the pistons were worn enough to see a different gap to the cylinder depending where you looked. The bottom of the pistons inside showed the overheating that the leaking head was causing. I ordered AA 90.5 69 stroke PCs which are the normal style piston, not the slipper skirt style of the stroker ones. They are nice and light with graphite coating and drilled oil holes. I had a pair of bare 041 heads there were ok used so we are working with them. I ordered new made in Italy SS valves (40x32).
Since the engine had thick wall 88 cylinders, the new 90.5s won't fit. The answer was to turn down the base of the cylinder 1.5mm to a tight register of 10 thou clearance to the case. As the trimming was being done to the outside of the cylinders, Steve also decked the cylinders to the case to get an exact height installed without shims. The slight radius where the deck edge meets the lower part of the cylinder was retained, just like factory machining. He likes squish so we decided to go with a super tight 30 thou deck (see pic). Then the heads are being milled down to get the desired 9.5:1 CR to get the squish happening. As the milling is done, the squish pads get larger which is good. This is going to be a low speed mini torque monster. With this awesome Nairex cutter he gave the sealing surface inside the head a slight texture to help seal as it crushes into place, and up the side of the hole he gave a different finish as it's enlarged for the 90.5s.
Note in the pic where you can see both chambers how much more squish pad area is there after the milling.

[markvo]

I would not go less than .043 deck height, as the piston at speed, will hit the head!  Compression ratio with your 47cc head with .043 deck, would still be 9.21 to 1
What cam and carbs and octane fuel are you running? What is the elevation above sea level?

[modnrod]

Engine pics, cool! 

Would you have some pics of the cylinder base machine work you had done please?

I like little motors, they just sound "busy" and "urgent", especially with the old 041s, hard to describe though. The higher comp should make it crackle a bit!

[Martin S.]

I meant to get pics of the cylinders on the lathe. I'll try for some today. The chuck had to hold on to the outside of the part at the top that extends above the fins, just enough there to grip and make 3 or 4 passes to slim down the base without the cylinder coming loose in the chuck. He said the cast iron wore out his tool quicker than expected, especially with new cast which is not work hardened yet. He's only done that operation once before on some birals as normally the case is opened but this time there is no need to split the case.
The idea of the tight deck is squish. Only have enough to not have the piston hit the head, and because of the low speed intended for this motor 30 thou will suffice. When he was drag racing VWs he has run deck so low that the piston has hit the head and even then there was no damage. The squish idea worked so well on my turbo motor that I want it on my other engines. Cool heads are the result. Everything that goes in gets burned, so efficient, like a damn miracle!

The engine is for my wife putting around town mostly, she doesn't need/want a screamer so it's running a stock carb and cam with regular fuel (87 octane) at just about 250' above sea level.

The other reason for a textured surface cut into the head chamber is to collect and retain carbon. The carbon acts as a heat barrier similar to thermal coatings. Don't clean the piston tops!

[markvo]

The AA pistons have about .002 more piston to wall clearance than a Cima/Mahale! The pistons will rock and carbon will add about .010 it may unseat the rings. I did a test on a stock VW motor going from 7 to 9 to one on the same day. The detonation on the 9 to 1 was so bad with 9 to 1, I couldn't even make another pull on the dyno,even retarding the timing and upping the jet on the stock carb! That was on 91 octane about 50 feet above sea level.

[Martin S.]

Berg was a proponent of the 7:1 engine and I built three of them 15 years ago. They worked fine, but always got poor fuel economy and didn't make the power I hoped. This new build is an experiment to see if squish can overcome those problems. A high squish chamber minimized pinging by design, not by lowering CR.

I dropped by the shop today and snapped a couple more shots of the progress. The SS valves arrived and machining is done. These old CB 041 heads measured only 3 thou difference between the two heads when put on the mill !! .040" or about 1mm was removed from the heads revealing more squish area. Final compression ratio is 9.6:1. Deck is .030".
Note the tool used for the flame port has 3 cutting edges.

[modnrod]

I know your build is all about utilising and maximising the engine using the parts you have, but I'm sitting here wondering whether welding the chambers up opposite the plug to get a deep but narrow "heart" shaped chamber for ultimate squish ratio percentage, is even worth the bother compared with just milling it down to get a wider but shallower chamber with the same cc's?
It does seem like a lot of extra work to g the welding route, when your way of optimising squish is vastly quicker and easier.
 

[markvo]

Good luck, make sure you clean up the exhaust ports, If you run the wider 11.3 by 912mm alt. belt and add about 8-12shims between top alt. pulley, the fan will turn faster, for more low speed cooling!

[Zach Gomulka]

Still running the small stock exhaust valves?
Which cam?
Why didn't you go with 94's? Same amount of cost and work...

[hotrodsurplus]

Berg was a proponent of the 7:1 engine and I built three of them 15 years ago. They worked fine, but always got poor fuel economy and didn't make the power I hoped. This new build is an experiment to see if squish can overcome those problems. A high squish chamber minimized pinging by design, not by lowering CR.

I have encouraging words for you: the tight deck and increased effective CR will indeed reduce if not eliminate your fuel economy and power issues. I fell for Berg's theories in the '80s and in 1993 I had my heads hemi cut when I rebuilt the engine they were on. That turned a wonderful running stock 1600 into a lazy, hot-running, gas-happy pig with major flat-spot issues. I had to use third to buck a headwind. I couldn't sustain 65mph for long periods without the engine running alarmingly hot--like down-on-power hot. I burned a set of rings in like 15,000 miles and the valve guides were loose. I followed all the dogma, including advancing the timing.

Three years ago I bought a pair of new heads. I had the step flycut. My deck is .050" as the result of faced case openings from the rebuild. I can't remember exactly but I think the chambers measure 48cc. Whatever they are, the static CR comes out to 8.1:1. I run Kadrons and a Mallory set to 10 initial and 30 total (it hated 32 total and is lazy at 28 total). With a stock cam at sea level I usually run 89-octane fuel. I heard some light rattles here and there but that was with a leaner tune. Now that I've fattened it back up a bit I need to try 87-octane fuel again.

Now the engine charges up any hill and can push a really nasty headwind with relative ease (in a lifted Thing with a surrey top--probably the worst aerodynamic combo). I almost have to work to make the engine run hot and I go 70 to 75 on the freeway whenever legally possible (I have photos of the GPS at 81mph--did I mention it's a Thing?). I frequently drive over one of the gnarliest mountain passes on the west coast and I need to hit third in only two spots. And they're relatively short spots at that. Bear in mind that the only air-cooled cars that weigh more than Things are transporters and Type IVs.   

Even with the super-tight deck I still suspect you may have some detonation issues at sea level with a stock cam. The stock cam reduces the static CR by .5:1 to create the effective CR. As a rule of thumb 92-octane fuel will sustain an 8.5:1 effective CR at sea level. There are exceptions to the rule--like a more efficient chamber design will resist detonation to a greater degree. Note that I'm not trying to discourage you. If anything I really want this to work. Me an' Javabug have been talking about building such an engine but finances prevent it from happening anytime soon. You're our guinea pig. 

Hey, if all else fails you can bleed off a little of that effective CR with a slightly more aggressive cam. And as a bonus output would increase across the board provided you matched the induction to the engine's needs. But I really hope that 92 will sustain your target CR. I mean if a carbureted V-8 with only a little more cam than we use can handle 11.5:1 then why can't we run 9:1?

[benlawrence]

a freind of mine just put together a "Bitser" engine out of old stuff laying around, this comprised of a set of 92s, old c/w crank, engle 120 and a bunch of other used stuff that measured out ok.  He had a set of 1300 heads that were good no cracks and the valve seats were still in good shape, he cutback the exhaust guide and cleaned up the exhaust ports but that was it, new stock valves no valve/seat job, left the inlet ports as stock, flycut the heads for 9.6-1 and threw on a set of chinese empi 40's and a cheap used 4 into 1 exhaust.
It really is about as basic as it gets, on fire up i put an initial tune on it and was surprised how snappy the motor sounded, we installed it in an old race car and took it round the block, it lights the tyres in 1st and 2nd (lightweight car)

we then stuck it on the dyno just to see and i was very surprised, it made 122flb tq, and 101bhp, on a dyno dynamics chassis dyno, a ton of fun on the cheap, im sure with minor work on the heads we could squeeze a bit more easily but as a throw together engine that measured out ok everywhere its hard to beat it for fun.

[Martin S.]

Good question about using 94s. I'm paying for this rebuild with wife's cash so there is no budget for welded heads, new cam, etc. She likes the car because it's a stylish economy ride. I'm going with Steve's recommendations and he says it will run fine on regular 87 gas. I'm ok with using premium if it gets better economy, but he says it won't ping. I believe him because he's got the experience from years of breaking parts racing. In the 90s when Berg was racing on the west coast, Steve was a young teenager building motors every weekend on the east coast and doing very well. Here's a pic of one of the race motors that turned well over 10,000 rpm until...

[markvo]

You can run 1.4 rockers on a stock cam ! I have, it made 10% more power though the whole rpm band. Just make sure you have enough clearance from retainer to guide boss in the head and no spring coil bind! You can always add rockers later you may want chromemoly shorter pushrods too with a heavy duty single spring at least.

[Martin S.]

I asked about using 94's vs 90.5's and he said that 94's would have too high a CR with the deck height we want (.030). The heart shaped chamber with more squish area is a good idea he said too! Also moving the plug in and adding more squish area on the opposite side would be desirable as well. The heads are together and the cylinder lengths all set to the thousands of an inch (by matching individual cylinders to their respective places with respect to the absolute seating area height). Number 3 seating area on the case is slightly pounded out due to that cylinder running hot and the head lifting and wearing the case so that cylinder will be slightly longer to keep the deck height consistent among the four cylinders. DECK HEIGHT is key here. The heads are assembled now and the engine is ready to assemble. Here's a pic of a finished head. Chambers measure 48cc, deck is .030 (3.22 cc) CR is 9.6:1.

[Martin S.]

Long block is together, next step is setting up the rocker geometry and assembling the tin. Does everybody agree on the 18 ft lbs. of torque for the 8mm stock head studs?

[hotrodsurplus]

Long block is together, next step is setting up the rocker geometry and assembling the tin. Does everybody agree on the 18 ft lbs. of torque for the 8mm stock head studs?

18 lbs-ft dry. Don't know how you assembled yours but I see a lot of people use oil, antiseize, and thread locker on critical-torque fasteners. That will skew the torque load and damage studs and/or cases. "Lubricated" torque specs are considerably looser due to the friction reduction.

Not that it's a huge deal but setting rocker geometry without the pushrod tubes installed makes life a bit easier.

[richie]

Long block is together, next step is setting up the rocker geometry and assembling the tin. Does everybody agree on the 18 ft lbs. of torque for the 8mm stock head studs?

18 lbs-ft dry. Don't know how you assembled yours but I see a lot of people use oil, antiseize, and thread locker on critical-torque fasteners. That will skew the torque load and damage studs and/or cases. "Lubricated" torque specs are considerably looser due to the friction reduction.

Not that it's a huge deal but setting rocker geometry without the pushrod tubes installed makes life a bit easier.

Chris

if you do them dry how do you know you get a consistent reading? the friction from different nuts to stud and or washer seems to vary greatly to me so I do them with stud/bolt lube on the threads and on the washers


cheers Richie

[hotrodsurplus]

Chris

if you do them dry how do you know you get a consistent reading? the friction from different nuts to stud and or washer seems to vary greatly to me so I do them with stud/bolt lube on the threads and on the washers

cheers Richie

It's easy to get a consistent reading: do them dry. I know that sounds smartassed but it's valid and it was a point driven home with great emphasis when I worked with ARP on a fastener tech piece.

I have a mayonnaise jar with an inch or so of acetone in the bottom. I drop all of my head nuts and washers in it for an hour or so, blow them off with compressed air, and store them in a clean place. Before I drop the head on I cover the cylinders and spray the threaded ends of the studs with brake cleaner and wipe them with a terrycloth towel. Maybe it's superstition but I feel as if the fibers better displace into the threads to clean them out. They always look dry when I'm done. I avoid spraying the studs with compressed air. I don't want to blow grime into a fresh cylinder for obvious reasons.
 
Now this assumes that the threads are clean. Rust will definitely interfere with torque values. So for that reason and to make fasteners go on by finger force I chase every thread with a tap or die. In critical applications like aeorspace the class fit (1A, 2A, 3A, and so on--aerospace often uses 3A and 3B) is critical and a garden-variety tap will destroy the tolerance. It's best to use a dedicated thread-cleaning tap in those applications. But tolerances aren't all that tight in automotive (usually 2A and 2B). Good quality taps and dies are just fine. In fact if you do this to every fastener in your car you will find it so much more enjoyable to work on it. Fighting bollocky nuts and bolts is for the birds.

Of course it's not the end of the world to do it with dirty and/or lubricated head nuts. A lot of us do it on a consistent basis and I did it that way for years. But it's considered poor practice and may cause issues in specific applications. To do it by the book eliminates that variable.

[Pedalpusher]

I have a mayonnaise jar with an inch or so of acetone in the bottom. I drop all of my head nuts and washers in it for an hour or so, blow them off with compressed air, and store them in a clean place. Before I drop the head on I cover the cylinders and spray the threaded ends of the studs with brake cleaner and wipe them with a terrycloth towel.

I did that way too, and chased the threads of the headstuds to remove any bits also. Nuts move really easy on the studs then.

Do you use any grease or something under the washers on the heads when you torque the thing in place? To prevent any oil from the heads to go on the other side.

-Mikko-

[hotrodsurplus]

I did that way too, and chased the threads of the headstuds to remove any bits also. Nuts move really easy on the studs then.

It's an old-man luxury. When I was young I just suffered with sticky fasteners. I do not have that much patience anymore. I am grumpy.

Do you use any grease or something under the washers on the heads when you torque the thing in place? To prevent any oil from the heads to go on the other side.

No. I install the washers dry too. I never had a problem with oil leaking from the stud holes in the heads. The oil would rather drain down the wall than flow sideways out of those holes. 

[Dalland]

..... Flame port.....
.....singh groove....

Looks cool for people that don't understand combustion engines....

[Martin S.]

Heh yes doesn't it! Another snag in assembly. The old Berg crmo pushrods are too long now with this new build and the close deck height. I'm going to find some stock aluminum pushrods and use those instead. The engine should run quieter with the al pushrods anyway. Interesting that the 15 year old 75,000 mile Berg single springs still have life left in them and are tight. Hopefully not too tight for stock pushrods. Steve loves VW valve springs and has replaced both Porsche and BMW race engine springs with VW springs (NOT Chevy ones). Long block went together with a quick lap of the valves and he found some leak down. Being the perfectionist that he is, it's coming apart to do more lapping. I'll let him explain that to the wife! 

[Martin S.]

Turns out that the seats were out a fair amount. The lapping ended up taking forever and he said he's never seen seats do that, especially not on a racing engine. It's done now and seals good and is back together still with the too long pushrods and a number of rocker stand shims to get them to work to check the leak down. Meanwhile check out these interesting pieces that arrived at the shop. Anyone guess what these are for?

[modnrod]

Anyone guess what these are for?

Cool! I like guessing games!
No good at them, but I like them.......

They look to me like cast iron barrels or transfer tubes out of an old boiler or for a steamy motor (ships?).
I rekn they would be just the thing to make up into custom barrels.

[Martin S.]

Good! Those are centrifugally cast iron blanks for making cylinders. They're from the same guys in the US that produce cylinders for bikes. If any of you are following Revmaster on their FB page you may recognize the same pieces in this picture... https://www.facebook.com/photo.php?fbid=553729827974780&set=a.316978494983249.95435.316970098317422&type=1&theater

[Martin S.]

The engine is back in the car now. Steve's super happy with it saying it starts instantly and burns whatever mixture is thrown at it. He's driven it around a little, and even though it needs to be broken in, he's tried a third gear roll-on from 1000 rpm and it's super responsive and NO PING! I asked about what happens if the piston ever touches the head with a tight or zero deck motor. Apparently nothing happens but you can hear it. The go kart racers run theirs up until the piston touches and you can hear a ring when it does. That's when they know their engine is set up correctly. I'm looking forward to driving the car again and I'll report my impressions and fuel economy. 

[hotrodsurplus]

even though it needs to be broken in

Huh? That doesn't make much sense. The cam breaks in well before you start driving the car and if I have it right you're reusing an existing camshaft anyway. What else is there to break in? Certainly not the bearings--they don't even touch anything. At least they shouldn't.

Now he has to seat the rings and the last thing you want to do at that stage is baby an engine. Do you think all of those sprint and drag engines get tenderly broken in? How about all of those engines that go on the dyno first for tuning? They go like hell for leather the moment the cam gets broken in.

What base and total timing is he running with that CR/deck? I'm really encouraged that it does so well on pump with a stock cam.

[Martin S.]

It's still got the regular 87 gas from a month or so ago
As for break in, he's a firm believer in the procedure. He says that many times new engines have been damaged on the dyno or drag strip because they haven't been broken in. Besides the ring sealing which is kinda obvious, he says that a coat of carbon on the new parts needs to be there to insulate against heat transfer into the piston especially. If the engine is run too hard right away, you run the risk of heating the rings and losing the heat treat and seal. Plenty of people make this mistake, but I've always been careful to break my engines in properly.
He says the distributor I have on the engine has too much total advance. Right now it's at zero at idle. He needs a timing light to check actual numbers so I'll dig mine out and find out the timing.

[hotrodsurplus]

He says that many times new engines have been damaged on the dyno or drag strip because they haven't been broken in.

I'll agree that lots of engines have gotten damaged on the dyno or drag strip but unless it's cam related it has little-to-nothing to do with break-in procedure. Damage that early in an engine's life is from improper machining or assembly.

Besides the ring sealing which is kinda obvious

Your chances of establishing a good ring seal decrease if you baby an engine during the seating stage. The ring needs to encounter a pretty significant load in both directions if it's to conform to the cylinder wall. That means vigorous acceleration and frequent hard deceleration. It holds especially true when trying to break in very hard chrome-faced rings. You have to run those extra hard otherwise they won't seat for a damn.

he says that a coat of carbon on the new parts needs to be there to insulate against heat transfer into the piston especially.

With that tight of a deck the piston crown will remain largely bare. There won't be much of a buildup in the combustion area if the tune is right.

If the engine is run too hard right away, you run the risk of heating the rings and losing the heat treat and seal. Plenty of people make this mistake, but I've always been careful to break my engines in properly.

The only way you can overheat the rings to the point of losing ring seal is to overheat the engine and that's irrespective of whether the engine is fresh or aged.

The 'run it easy' school of thought is a holdover from grandpa's day and actually threatens to do more harm than good. I'm lucky to work with some very prominent manufacturers and engine builders and if they've reached consensus on anything it's that the slow-and-easy process required for flat-tappet cam break-in is a burden that threatens the integrity of the ring seal.

Don't take any single person's word for it--certainly don't take my word for it. Call some reputable dyno operators. They're often engine builders and they know their stuff.

He needs a timing light to check actual numbers so I'll dig mine out and find out the timing.

He builds engines and doesn't have a timing light?

[modnrod]

He builds engines and doesn't have a timing light?

Good engine builders and tuners can time it by ear anyway, and so are not overly worried if their timing light is lost under a bench somewhere.

Not to get involved with an argument, coz we all know an argumentative website or a dogmatic website is a soon-to-be-quiet website (like others in the near past..........), but there are still many different trains of thought and ideas on engine building, assembly, useful features or otherwise, and also running-in procedures.

I'm interested in the end results too, it sounds like a great success! I rekn it must crackle and fart on over-run........