Big Valve 1.9 head

[Tru-Craft]

I wanted to put my thoughts and things I have learned doing this big valve head project in a thread while its still fresh in my head. First I wanted to thank Bob L. for his many posts and pictures on this topic as well as many others! I will try to make this an overview of what it takes to tackle this project. I have been in the Tool & Die/Model making trade for over 30 years and might look at some areas in a different way.
This is not an easy project!
I started with a stock 1.9 1970 Opel head 10 bolt.
Removal is easy just follow the manual. Since my block was already done with Chevy pistons I just needed to clean the gasket off and clean everything! One thing I did was to use a wet vac to suck out the oil and anti freeze from the piston bores and all passages, works great! Spin the crank over and wipe out the bores! Coat everything with motor oil and cover it up.
Dis-assemble the head and mark locations if original parts are to be reused. The first thing is to do a rough hot tank cleaning and get the head magna fluxed for cracks.
Then as Bob recommends remove all oil plugs and rocker studs, this is very important! You won't believe how much dirt is trapped in the blind holes and under the studs, and this will not come out by hot tanking. Tap the oil holes for pipe plugs or get new press plugs. Also remove the dowel pins.
The head is now ready for a trip to the machine shop. This is not as easy as it sounds! This is not standard stuff! Not every auto shop can handle this project! Dave(Nobody) has found a shop that does good work. Do some research before you drop off the head!!!!
Give the shop a copy of Bob's valve size suggestions. I used 1.800/1.500 pro-flow Chevy valves. Have them install hardened exhaust seats and bronze guides. Then have the valve seats roughed in only!
Port & polish as Bob shows, and un-shroud the valves. If you have a steady hand and the tools, it will take a couple days. The large 1/2 Dia carbide burr is hard to control, but does make the job quicker.
I then milled the intake/exhaust mounting surface to just cleanup, then I angle milled the head to get the chamber volume down. About .080 on the sparkplug side to ".010" on the other side. This drops the cam about 035 and cam timing will need to be adjusted. Also had to re-spot face the head bolt holes.
File all sharp edges in and around the combustion chamber about (.010 to .015 rad).
One thing I have learned from living in humid Florida is to protect the bare metal surfaces from rust! I have used "Ospho" on all my machine tables and tools for years, it works! Use it on the freshly machined head, and a little WD-40 and no rust!!!!
Next I made 2 new dowel pins for the intake manifold, .314 in the head and .330 to tightly fit the manifold and gasket. Locates them more accurately. Also make sure the gasket matches the intake manifold.
That's as far as I have got.
Lyle

[Tru-Craft]

Here are a couple sketches of the head modifications I made.
The 1st picture is of the valve guide cross section, this shows that I reduced the height of the intake and exhaust guides about .200 from stock. This was done to improve flow and to match the under cut stem on the Pro-flow Chevy valves.
The second picture is of the head showing the dimensions after angle milling. Milling this way instead of straight milling dropped the cam only about .035" from stock, but reduced the combustion chamber volume alot more.
Good idea Bob!

[Tru-Craft]

The engine shop checked the volume of one combustion chamber today. It was about 49.5 cc's!!! Stock is about 52.0 to 52.5 cc's.
To reduce the volume after un-shrouding the valves, I had to angle mill the head. Also the valves were seated shallow so they would take up more volume. I'm using 1.800/1.500 Chevy valves.
Here are the approximate numbers I came up with:
3.75 Bore/ 2.75 Stroke, volume = 497.8 cc's.
Combustion chamber volume = 49.5 cc's
Head gasket volume = 0.3 cc's
Piston notch volume = 2.0 cc's
Piston/top ring volume = 0.2 cc's

So if I take 497.8 divided by 52.0 = 9.573 compression ratio.
Great for pump gas!

Valve springs are next. The race shop I'm working with has a good selection of 1.44 dia springs, Titanium retainers and keepers. So I will use what he has to give us 105 closed/ 250 open. Also I have to make sure they clear the roller rockers I got from Gregg.
I do some machining for his shop, so I get stuff free or real cheap!
Lyle

[Tru-Craft]

Head is back from the shop. Springs are 1.44 dia, seats cut to give 105 closed pressure/ 260 open. Painted the head red of course!
Made an aluminum oil riser tube for the oil drain hole.
Modified the head gasket, added 2 holes as recommended by Bob, and made up a .032 gasket to take up the step on the front timing cover.
Installed the cam bearings and checked clearance (.002").
Put lube on the cam lobes and lifters and installed the cam from "Cam Techniques".
Time to check the valve to piston clearance. Bought some Red Play dough, put it on the #2 piston, old gasket on the block. Sprayed a little WD40 on the head so clay wouldn't stick. Head on, not bolted down. Cam sprocket on and timed correctly. Carefully rotated the crank (by hand) about 6 times. Removed head and checked clearance. Intake .085" away from bottom and about .05 away from the edge of cutout. Exhaust .115" away from bottom and .090 away from edge!!!!
Lyle

[GTJIM]

Things are looking good - maybe just a whisker more clearance around the intake valve depending on how 'loose' you set up the pistons in the bore and therefore how much piston 'rock' you get at TDC. Otherwise everything has turned out OK. Wise to check with the head bolted down with a couple of bolts perhaps to make sure the clearances are correct......

Play Dough RULES!!!

[jeff denton]

Lyle, think about draining your head externally, like I do. It's too simple, and dumping oil onto the rotating assembly downstairs just irks me after all the work it takes to control windage!

[Tru-Craft]

Jim, I put the head back on and bolted it down in the center and re-checked one more time. Clearance still looked good. Pulled head off, cleaned the surfaces. New gaskets and O-ring seal, permatex around the timing cover and the head back on! My back is sore!!!!!
Timing marks lined up, chain tensioner tight, distributor to #4.
Torque the head bolts.
Bolted everthing back on, set valve lash, poured oil over the valve train.
Coolant, fuel, spark.....that's was a lot of work!
Set timing to about zero so it will start easy.
Turned the key!

[Tru-Craft]

Lyle, think about draining your head externally, like I do. It's too simple, and dumping oil onto the rotating assembly downstairs just irks me after all the work it takes to control windage!

Jeff, can your oiling system be added with the head on the car?
Lyle

[jeff denton]

It's just a 90 degree -10 fitting welded into the rear cam cover as low as possible, notice this comes out a little higher than the drain hole just an inch forward, thus it causes the "puddle" that the riser tube does. Then a -10 stainless/teflon hose goes down to the side of the pan to a -10 45 degree fitting. It is that simple... in fact it could be simpler yet with just nipples and a rubber hose, I just like the good stuff and since I worked at a truck shop when I did mine it was all available. All truck shops have this stuff, it's the hose and fittings between any truck's air compressor and wet tank.

[Tru-Craft]

Hooked up the battery!
Cranked it until fuel got to the carb and it fired right up
Oil pressure came right up!
Sounded good, no valve/piston tapping sounds!
Brought the Rpm's up to 2,500-3,000 and let it run for 20 minutes to seat in the cam.
Let the motor cool down, re-torqued the head, manifold bolts, hoses.....
Set ignition timing with an adjustable timing light to 17 degrees, max advance 36 at 3,000 rpm. Took it out for a ride and was very happy, great hot cam sound and awsome power above 2,000 RPM!
I still need to do some fine tuning (38DGAS carb/ignition) to get it right.

The only problem I had was with the "new style" polylocks for the roller rockers Gregg sent me.
The valve lash kept going out of adjustment. I checked the cam lobes, rockers, valve tips and they all looked good. Then I checked the polylocks......they are soft steel and have only 8 threads holding them on!!
Gregg, is sending me a set of the "old style" polylocks, to cure this problem, thanks Gregg!

I just wanted to thank everyone for the great posts and all the help.
My GT is running the best it ever has!!!
Lyle

[Tru-Craft]

It's just a 90 degree -10 fitting welded into the rear cam cover as low as possible, notice this comes out a little higher than the drain hole just an inch forward, thus it causes the "puddle" that the riser tube does. Then a -10 stainless/teflon hose goes down to the side of the pan to a -10 45 degree fitting. It is that simple.

Jeff, so the stock oil drain hole drops oil on top of the crank, your system puts it back to the oil pan. Thats a good idea!
So I plug the aluminum oil tube I just made.
Go down to the hydraulic shop and get some hoses and fittings.
What is the ID of the #10 hose about?
Pull the pan and install a #10 fitting, how far up?.
Have any pictures?
Thanks
Lyle

[jeff denton]

I don't have any pics, I hoped it might show up in that shot from underneath in the "flywheel tooth count method" thread but I just looked, it didn't.
The 45 degree fitting on the pan is just below the level of the top of the oil in the sump. In the side of the fitting I drilled and tapped it for a 1/8" pipe plug, I check oil level by removing this plug and pouring oil in the valve cover until it runs out said hole. (I don't like dipsticks in race cars...)
Anyway, in the hosing business, -16 is one inch ID. -8 is half inch, -12 is 3/4 inch, see how that works, by the sixteenth of an inch? So -10 would be ten sixteenths, or 5/8.
Look under the hood of any big truck, like a Kenworth, Mack, Freightliner or Peterbilt kind of big truck. See the pretty hot rod style braided stainless hose coming off the air compressor? That's the stuff. Truck shops have it by the roll, have the dies and fittings and press, they make up new ones every day because they are a very common failure on a truck... cost a lot less than what hydraulic shops charge.
Don't worry about the hose failing in this application, they fail on the trucks for reasons that actually point to a problem in either the compressor or the turbocharger...
To plug the oil drain hole I just shot some Right Stuff in it.

[tekenaar]

Jim, I put the head back on and bolted it down in the center and re-checked one more time. Clearance still looked good. Pulled head off, cleaned the surfaces. New gaskets and O-ring seal, permatex around the timing cover and the head back on! My back is sore!!!!!
Timing marks lined up, chain tensioner tight, distributor to #4.
Torque the head bolts.
Bolted everthing back on, set valve lash, poured oil over the valve train.
Coolant, fuel, spark.....that's was a lot of work!
Set timing to about zero so it will start easy.
Turned the key!

Great job, well thought out headwork . . . like the billet air filter cover too. Later post says it runs great. Only question/suggestion I have is, "With all the effort you expended on improving engine performance, have you thought about the free additional performance to be had from a 'cold air intake', especially in a GT?"

I admit to being a 'cold air' bigot of sorts, especially in GTs. Because of the GT's much more limited underhood room, temps on the intake side tend to be much higher than in other models and, without some sort of 'cold air' intake, this is what you end up sucking directly into the engine.

You have to ask why the factory went to the trouble of designing the stock GT air intake the way they did if they didn't perceive it as a problem. Also note that all the later models had some sort of snorkel forward of their air filters to draw in cold air . . . MUST be something to that, wouldn't you say?! I digress . . .

[GTJIM]

The only problem I had was with the "new style" polylocks for the roller rockers Gregg sent me.
The valve lash kept going out of adjustment. I checked the cam lobes, rockers, valve tips and they all looked good. Then I checked the polylocks......they are soft steel and have only 8 threads holding them on!!
Gregg, is sending me a set of the "old style" polylocks, to cure this problem, thanks Gregg!
Lyle

Great news! Sounds like your head went together right.

Yep. Those poly-locks do need to be hardened where they contact the rocker fulcrum. Especially with solid lifters as the wee bit of valve clearance does allow some "hammering" to take place. minimum thread engagement is usually regarded as one diameter of the thread - i.e. 10mm in this case, which is 10 threads of the 10M X 1,0 pitch thread.

[Tru-Craft]

Otto, have looked at the cold air intake before, just got side tracked. Also want to do a heat shield over the header pipes like you did! Next projects!
Lyle

[Tru-Craft]

Great news! Sounds like your head went together right.
Yep. Those poly-locks do need to be hardened where they contact the rocker fulcrum. Especially with solid lifters as the wee bit of valve clearance does allow some "hammering" to take place. minimum thread engagement is usually regarded as one diameter of the thread - i.e. 10mm in this case, which is 10 threads of the 10M X 1,0 pitch thread.

Thanks Jim, real happy with the head! I learned a lot.
Your right the polylocks should be harder. I checked them and they range from 41-43Rc. probably a mediumm carbon un-heat treated "soft" steel. The Opel rocker arm nuts check about 48-50Rc. A good grade allen head bolt (SHCS) checks about 53Rc. Do you guys use the Rockwell "C" scale to check hardness?
They showed damage on the bottom and the threads showed signs of stress cracks with only 4 hours of use! I was worried my cam lobes were soft or something!
Like you said at least 10mm of thread in contact. 1-1/2 times diameter is better, for the load and pounding they take! These have about 8mm!
Bob's original design (old style) was a 10mm threaded hole all the way through, with a 10mm set screw. That polylock had about 14mm of threads holding!!! Why change a proven design???? Rumor is a 10mm x 1.0 pitch set scew is very hard to find.
Gregg has been great, and is sending an old style set for me to check out.
Lyle

[RallyBob]

Bob's original design (old style) was a 10mm threaded hole all the way through, with a 10mm set screw. That polylock had about 14mm of threads holding!!! Why change a proven design???? Rumor is a 10mm x 1.0 pitch set scew is very hard to find.

Why change a proven design? Because the owner of Cam Effects will spend $2 to save .50 cents. Go figure. I actually gave him the name of the source of the 10mm x 1.00 pitch set screws, he opted instead to double the manufacturing procedures (two hole diameters, two different thread pitches) in order to use cheaper set-screws. And there have been nothing but problems with this decision since the beginning. He seems to take great joy in taking an existing design and changing it, but not necessarily for the better.

Bob

[markandson]

So, what's the source. I have a set of rockers that I can't use unless we solve this problem.

[opelnut10]

Maybe this guy is a believer in "bigger is better" theory. Youhave met them I'm sure. If a 36mm carburator is good then a 45mm carburator should be better and two of them will be wonderful, if a .450 lift cam is good a .550 should be better and a .650 will be wonderful, etc. Maybe he thinks if a 10mm set screw works well a 14mm set screw will be wonderful

[neuropel]

So, what's the source. I have a set of rockers that I can't use unless we solve this problem.

Confused...does this affect everyone that bought the roller setups from Gregg?