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The bellows thermostat is usually fully open long before the cht peaks.

At one point I was measuring cht (tc under plug) and airflow temp (not touching or supported by the heads) about 1cm down from the head in airflow off the heads, under the exhaust valve guide. The exhaust valve guide air did not always mirror cht, but I have forgotten the details.
(on t4 heads there are fins and decent airflow around the exhaust valve guide and even the port sides, port points down)

Update,

I've been working on the Buggy for a couple weeks since the weather finally warmed up a little bit. I pulled the engine and found the #3/4 head had some serious issues. The #3 exhaust valve guide was completely toast and the guide support was worn so bad the guide fell through and was bouncing on the valve head. There was a big piece missing but no damage to the turbine side of the turbo for some reason....
The #4 guide also was up about a half inch so the DRDs head are toast in my opinion.
I then pulled my stock heads off the shelf and disassembled them along with the DRD heads and swapped the CB 650 outer springs and cromoly retainers to the stock heads. Everything else looked good on the stockers except the small cracks between the valves but I'm just going to run them as is for a season.
We don't have a long trip planned so it should only be about 3500-5000 miles for this year.
I took the stock heads to the neighbor and had him cut 0.070" off the rocker pad and doing the setup on rocker geometry it came out so nice I don't need new pushrods. I have zero shims on the pads and the half lift and swipe came out so great I'm happy as it is. My adjusters are out 2.25 turns instead of 1.5 turns so it's still good in my opinion. The sheep's feet and lash caps show no abnormal wear in the 10,000 miles they have been on.
Valve lift comes out at .503" and cam lift is at .363" for a 1.39 ratio.

I did find one pushrod had rubbed against the bottom of a pushrod tube and worn a good bit so I had to order a new set of .035" cromoly pushrods to get one replacement. I'll cut that one to length and then finish up the engine and reinstall.

I'm headed to the Portland Swap Meet this next weekend so I'll maybe find some things I didn't know I needed.......

I have a 150 psi pressure sensor mounted on my full flow filter housing and will monitor oil psi either through the ECU or directly through an input on the ADU5 and then canbus it to the ECU.
I also have a spare IAT aensor that I plan to mount under the 1/2 head by the Stock Thermostat to monitor air temps for a season to see if it's worth messing with ECU controlled air cooling flaps....that remains to be seen....but since I have the extra inputs I might as well gather some data.

My goal is to have the buggy ready to start by the middle of April. I should be able to meet that goal.
Once the new pushrod shows up I can reinstall the engine and move on to a few other upgrades I want to do depending on weather forecasts.

My plan was to reupholster the seats but the guy is booked solid till almost June so it might have to wait.

The weather hasn't been the greatest for most of the winter and early spring so everything has been slow going. Hopefully that will change in the next couple weeks.

Those heads are offerings to the god´s of speed. Amen

You think you will have some loss of performance?

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How many minutes would you estimate, since installing the refreshed DRD heads, has your engine been at or near - say above 15psi - boost? Doesn't seem like they lasted very long even for normal (non-boosted) driving conditions!
Jeff

rubenski wrote: ↑Sun Mar 26, 2023 1:25 am Those heads are offerings to the god´s of speed. Amen

You think you will have some loss of performance?

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I never really noticed a gain with the DRD heads so I'm not concerned too much about any performance loss..

GS guy wrote: ↑Sun Mar 26, 2023 5:05 am How many minutes would you estimate, since installing the refreshed DRD heads, has your engine been at or near - say above 15psi - boost? Doesn't seem like they lasted very long even for normal (non-boosted) driving conditions!
Jeff

These DRD heads still have probably close to 32,000 miles on them if I have to guess. They just needed a lot of work in those miles.
Cheap valves, cheap guides and who knows what else. They are the 049 head casting but for some reason I've had no luck with them.
Some of this last problem could have been self inflicted but I can't say for sure.
I did do a LOT of idling setting up my IAC valve this winter due to crappy weather not allowing me to drive it after a start. That could have been a part of the problem but I don't know.
The guide support on the #3 cylinder is worn to almost 3/4 inch diameter while the guide is maybe 1/2 inch diameter. There was aluminum everywhere in the valve cover.

Maybe my EGT's are too high......I don't think my gauge is very accurate since I bought a new probe for $12.00 a few years ago and might not have it calibrated correctly. At rest EGT temps do not match the IAT or oil temp sensor before starting so I have some reservations on accuracy.
The DRD exhaust valve do not look like they were run too hot so it's hard to tell what caused it.

I'm going to run it for a season with the stock heads. They have held up very well and never seem to have a leakage problem since the intake ports are spotless whereas the DRD's had black soot from reversion all through the intake ports so I know they were leaking. When I had my Builder put new guides and valves in them last time he went through them it solved the leaking issue and they seemed to run good.

As far a boosted miles....hard to say. I drive it a lot and range from 4000-8500 miles a year. When we go on a long trip it sees very little boost in that time period since the turbo is used only to climb the many steep grades in the mountains. It only needs 3.0 lbs boost to maintain speed at 60-65 mph and most of that time we are at 5000 plus ft. in altitude so its really barely maintaining the 100 kpa of sea level elevation.
Having the new ADU5 digital display allows me to see real time what the engine is actually doing.
I don't really go to max boost that often anymore but it's still nice to have it. One run from 0-100 or more mph only takes about 10-12 seconds or a little more if I do an easy launch which I usually do.
Say I boost it twice a day for a season and that is 120 days at 20 seconds...... it would be about 40 minutes of max boost if that....... since max boost only occurs in 3rd and 4th gear.
Using those numbers at over 15 lbs boost I would say it might see 60 minutes of boost over 15 lbs per season. Since I can see 15 lbs boost by 3600 rpm and could get there in a short shift at 3600-4000 rpm.

Sounds like the heads are begging to be cut for dual springs! Is it possible that the vw650 outers are jumping around, or maybe aren't quite the same ID as a stock spring and maybe that caused the issue with the guide boss? I can't think of any other reason why unintended machine work would happen around those protected parts. The only moving part in there is the spring itself. Unless maybe I'm just imagining this incorrectly. Sad to hear about the failure though. Stuff like that always sucks. One more reason why I'm glad I took my old DRDs out of service years ago. I have planned to replace all of the removable hardware for years, Just haven't pulled the trigger on it yet. They look like nice heads, but I think they were just filled with cheap hardware.

You don´t have duals???

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Heading south to the Portland Swap Meet for 3 days.
PIR race track on Thursday afternoon. It's 2.5 miles of track with parts on both sides plus the staging area and pit parking area. We'll walk about 8 miles from noon to 6:00 pm.
Friday is the Expo ground with five 600 ft long by 240 ft wide buildings along with probably 5-8 acres of parking lot to go through. We'll walk another 8 miles from 8:00 am till 5:00 pm.
Saturday it's back to the track to make a fast pass from 8:00 till noon to see what we missed unless it's pissing rain.....the drive home is about 5 hours depending on traffic.
We'll have to see what I find that I didn't know I needed....

I've never been to a swap meet that Hugh ,, Years ago out Lansing swap had about 300 venders at one time Have not seen that in a very long time
I try to stick to my 'Shopping list' but that never works out,,, Have a Good one Art!!!

Update,

I survived the Swap Meet and didn't come home with any junk I didn't need.
I scored a Heat Gun for $15.00 to melt my heat shrink tubing.
A few S-K Wrenches to fill out my set.
Four 6 inch long S-K 1/2 inch drive extensions for a buck a piece.
A 25 mm Gear Wrench with swivel end for 10 bucks. It's actually 15/16ths too and I need it at work in the winter
Some name brand punches cheap.
A couple sockets.
A Fuel pump exactly like my Volvo pump for $10.00 brand new.
A cheap extendable 9.0 lb lift magnet.
Soap from a young girl working to ride horses to help her out,
Candy from one vender and some Landjaeger sausage to munch on at work,
$10.00 beers while walking the 6-8 miles per day and a couple corn dogs.
And some other stuff I can't remember.
There was very little VW stuff there and nothing that I needed or wanted to pack out.
All in all a good time dodging the rain and looking at junk and treasure.
The track was 6.5 miles of walking in 6 hours.
The Expo grounds were 8.65 miles of walking in 9.0 hours.
Then back to the track on the last morning for another 6.0 miles of walking in about 4.0 hours.

Back to the buggy.........

The engine is mounted back in the buggy and I am working on the wiring.
I added an IAT sensor under the head by the thermostat to monitor air temps coming off the head. I want to log the results and compare that to load, rpm and maybe boost levels.
I also added an oil pressure sensor to the oil filter housing to monitor that realtime on my digital dash. If I get bored with that I can always move it to my fuel line and monitor fuel pressure.

I've installed my stock heads and shaved 0.070" off the rocker pads and my geometry comes out really nice using the 0.035" cromoly puhrods.
The adjusters are out at 2.25 turns instead of 1.5 turns and everything looks good.
I had to buy another set due to one pushrod rubbing the tube at the bottom and wearing half of it away. My neighbor was gone so I put it on the lathe at work and shortened it myself. That's the first time I've run a lathe so I got it as close as I could with the measuring tools at hand.
I adjusted the rocker shims a bit to give me better clearance and also tweaked the tube a bit to make sure it doesn't hit again.
The DRD heads are toast and will not be repaired by me again. It will take some serious welding and machining to get them back in shape.

I hope to have the buggy running by the middle of April but weather isn't too conducive to driving yet. It's been cold and wet most all through the winter and spring . My ambition to drive when cold is lost due to being an old fart.

There will be no long trips this year so it will be local driving to and from work and on nice weekends with the other half.

I tried to get my seats redone but the guy is booked through June so that might not happen.

Mileage, 113,902

The buggy is running. I've got about 75 miles on it with testing and taking it to work for two days before the weather went to crap again.

It's running good with the stock heads back on. It needed some tune adjustment due to a lower kpa reading at idle and cruise but that didn't take long to fix up.
Some of the addons I've done are as pictured.

My new brake light switch that now bypasses the pressure switches on the master cylinder due to a late brake light that someone warned my about when I was leaving work.
I bought a switch online and built my own bracket. It took revision 2.0 to make it work. I run the ground based input into my PMU16 and it's programmed to flash quickly 4 times and then stay on.....kind of like motorcycles have on their brake light....for better visibility and hopefully safety.





The bracket....



Next is the IAT sensor under the #1/#2 head just forward of the Thermostat.......I can monitor the temperature of this sensor through logging on Tunerstudio and I also have it displayed on one of the 7 pages of my ADU5 dash.



I also added a 0-150 psi Sensor for oil pressure which is displayed on my ADU5 Digital dash.



Here is a pic of my toasted valve guide on the DRD heads.......



You can kind of see the enlarged hole for the guide if you look closely....it's probably an 1/8 inch larger diameter than the stepped part of the guide since it fell right onto the valve head and rode there for who knows how long.



Here is some of the Aluminum sitting on the sump plate.......



I need to install the rollbar yet and then it will be ready for another season.

I touched up my cold start IAC a little and it starts hands off with just a push of the start button.

The stock heads did change the vacuum a bit on idle and cruise so I have to adjust fuel and ignition advance to cover those areas....it's close but a little tweaking will make it better.
I've seen 21.5 lbs boost so far in the first five miles test driving with my brother. Hit approximately 110 mph in 4th gear.

I've also programmed the ECU to log altitude and I will be displaying that on one of the pages of my Digital dash. It's not quite matching the altitude I live at so far.....it's showing 32 ft. ASL and I live at about 108 ft. ASL.
It reads pressure altitude so it is not actual altitude compensated for temp and humidity. It calculates readings off the second baro sensor.
I'll figure out if it's close enough or not as a I get more time with it.
I have it more for if or when we travel up in the mountains again. Since it doesn't cost anything to add it except a little time researching how to write the numbers in the logging fields. I considered it more a challenge to make it work.

Cool that you have brake lights that are programmable. I like that

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Continuing to be an inspiration

rubenski wrote: ↑Sun May 07, 2023 11:46 am Cool that you have brake lights that are programmable. I like that

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It's really cool but it isn't cheap...... I love electronics though so it's worth it to me. The stuff you can program the pmu16 and dash to do is just short of amazing.
I've programmed my blinkers to blink six times by just bumping the turn signal on for a second. That way I can do a lane change without having to remember to turn off the blinker....
I get all these ideas from the new car technology that comes with my wife's car. The only issue is that you can run out of outputs since there are only 16 of them. The new version allows you to get 24 outputs by having 8 inputs that can be programmed as outputs or inputs.

Gosh.. I love technology!!!!