Hatchet: 1979 BMW 320i Race Car

Well, whatever numbnuts rebuilt these carbs put the rear carb butterflies in backwards.  Amazingly, when the butterflies can close all the way, the carb works a ton better. 

That was before it was fully up to temp. It was even better once it warmed up more but there's still room for improvement.

It's idling now at about 1k rpm which is a bit higher than I'd maybe prefer but it actually idled high with the CIS as well. Going through old videos, it sounds like it may actually be lower than it used to be. I haven't found a video of the gauge cluster during idle yet.

Hopefully today I can get a clutch stop whipped up with a target of driving it tonight or tomorrow so I can really tune it. The front seal kit should be here Thursday. Onward and upward!

I started noodling on the clutch stop this morning and found that I may be able to utilize where the factory stop was. 

I'd have to modify the bolt to miss the arm of the pedal and contact the pedal itself because of the angle. I think this is the way to go though. Keep it simple. 

I know this is sort of empty without a driving video but Hatchet runs awesome! If I'm being super particular, there were a couple times in second gear where there was a bit of stumble crossing over 2k rpm but I haven't even worked on the mixture or balance yet and it totally loves WOT.

In other news. There is a chance that really the main oil leak is from the valve cover, which I knew would leak because of the misalignment and I didn't use any sealant when I threw it on there figuring I may need to take it back off.

is that original color called Reseda Green? if yes, that's the same color as my '79 528i. hot.

In reply to AngryCorvair (Forum Supporter) :

Good eye! I would say that it's sort of a shame that very a cool, rare color got painted over but this thing was clearly such a rust bucket when it was first converted to a race car that I'm just glad it wasn't scrapped then.

Some updates. I removed the exhaust, made the hole larger, trimmed the tip and it bangs around in there just as bad as before. My remedy for next weekend will probably split fuel line shoved in around the hole but we'll see.

I spent some more time tuning the idle and then went for a test drive after turning fuel pressure down further because I'm still dealing with some drips out of the venutris. The stumble is definitely worse now and the idle hangs. My newly ordered low-pressure fuel pressure gauge showed up but didn't come with fittings that will work. No sense working on any more tuning until I know exactly what the pressure is.

Second round of tuning and testing today and, unfortunately, most of it isn't good news. 

Let's start with the good - fuel pressure is verified and set at a very nice and steady 2.8 psi. The fuel leak also seems to be gone as I actually traced it to the bottom cover, not the venturis as originally thought. 

I got the idle dialed in quite nicely and took it out on the road. The stumble is still very much there. It clears up every time but it's bad enough that it could be an issue coming out of tight corners. I've got some bigger mains and a bigger idle jet coming. 

The other issue I'm dealing with is one (or both) of the carbs is still hanging open, causing the idle to stick at 2k after heavy throttle. I've got two things I'm going to look into regarding that. First is the tightness of the throttle shaft nuts. Second is the accelerator pump may be sticking. 

The worst news? I thought the leak on the front of the engine was primarily the valve cover but is 100% is not. After idling for like 8-10 minutes to tune it and then a couple high RPM runs up and down the street it is dripping from everywhere. 

AxeHealey said:

In reply to AngryCorvair (Forum Supporter) :

Some updates. I removed the exhaust, made the hole larger, trimmed the tip and it bangs around in there just as bad as before. My remedy for next weekend will probably split fuel line shoved in around the hole but we'll see.

I was wondering about that when I saw the picture of it the other day.  Then I thought maybe a exhaust hanger as close to the exit hole as possible would help.  Don't know just a thought.

In reply to Stampie :

There's one about 7-8 inches from the outside of the rocker but, yeah, it probably needs extra support out toward the end. At this point, I've pulled this exhaust off so many times that there's really no excuse not to do it again and just hog that hole out as much as possible while still being able to put a pretty piece over it.

Last night I spent some more time with the carbs. First I loosened the throttle shaft nuts and it was still hanging up.

Next I pulled the top covers off and although I painstakingly set the float levels, they were both wrong and the front side was drooping so much that the needle was hanging open. I also pulled the pumps out and both looked good to my eye. No corrosion or anything although it sort of looks like someone put anti-seize or something under the plate for the rear carb pump. 

While laying in bed last night I realized that the front gasket kit I ordered did not come with a water pump gasket. I think considering I'm blaming the leaking on mis-alignment, I should pull the water pump off the cover too. No parts store around me can get one until August 5th so I've got a couple coming on Monday from an online source. Annoyingly, I can't get a new valve cover gasket until then either and I don't expect to see the new jets before then.

There's only so much I can do a right now but the plan is to pull the carbs to see if the butterflies shifted, see if I can identify some other reason one or both is sticking and then reassemble and check it all out. I'll then move to addressing the exhaust rattle, getting the brakes bled, giving it fresh diff fluid and whatever other little prep things I can cover so that once I have all the parts early next week I can tear it apart and get it back together quickly. 

Schenley is without question my favorite event of the year and I am determined to be there with Hatchet in good order.

EDIT: One of the butterflies on the front carb was just ever so slightly out of line. Boy are these carbs fiddly. Maybe too fiddly for this (seemingly) imprecise boy.

Newly uncovered rust holes. Fixed.

This one I actually welded in the patch, painted and "sealed" the stitch weld with Gorilla tape. The rest of the patches are just screwed into place with the same high-tech sealant.

"Finished" the exhaust setup. There is a re-positioned cut fuel hose and a large rubber buffer in there.

Diff fluid changed.

Brake fluid changed. I also put Hawk Blues in the rear. Last year I ran stock VW pads in the rear and I only ever locked the fronts and the bias valve is wide open. I figure the Blues should be more than enough no matter what and if it's too much back there I'll be able to dial it back.

I did a nut and bolt on the rear and driver's front. I need to finish the front end. I also want to put out in the universe that I'm going to nut and bolt the entire car, especially drive line, on Saturday night at Schenley.

Tomorrow the font cover comes off.

You running 323i trailing arms and E30 calipers?  

In reply to jmabarone :

No, the calipers are from an 80's Golf with an adapter. 

It's apart and I'm probably 2/3 done cleaning the mating surfaces. It's possible that the only remaining leak once the valve cover was remedied was the crank seal but I figured if the alignment was the problem, there was no way around taking everything off and starting fresh. 

The only real hiccup I encountered was the oil pan gasket ripping off which wasn't unexpected, to be honest. 

I think my plan will be to cut the two remaining pieces flush with the block and make a new piece to fit ensuring to get plenty of sealant into the corners. It's not ideal but there's no chance the pan is coming off at this juncture. 

Well, Hatchet continues to kick my ass.

I went out and got a bottle of the Permatex Aviation sealant and started to assemble with it but with all of the angles and reaching down it was nearly impossible for me to get the lower cover up under the tensioner, onto the pins and seated well without the gaskets moving around so I pulled it off, cleaned it again and went back to normal RTV which holds the gaskets in place better.

I was working very patiently and methodically but when I went to sinch everything down after letting it cure for an hour, the cork gasket I made for the front of the oil pan started to squeeze out. 

I loosened those three bolts, tried to slightly reposition the gasket, tightened it back down some and, as embarrassed as I am, slathered RTV along the seams. 

At this point I'm pretty out of options and just have to hope the leak that will surely be there is manageable. 

EDIT: Oh and the top cover still ends up proud of the top of the head. 

That's frustrating, I can't say I have ever tried to pull/replace that cover with the head still on there. 

Those cork oil pan gaskets are a pain in the ass too, for the M30 Victor-Reinz does a rubbery one that is nice but a quick search looks like the M10 is only available in cork.

You won't be the only one leaking a bit of oil though so hopefully it isn't too bad and you can focus on the rest of the car.

In reply to adam525i :

I could see using the Aviation sealant on a stand when things are more accessible. Thank you for the suggestion. 

The problem is that the cork piece I made is not attached to the rest of the pan gasket so there's nothing really to keep it from sliding forward. 

It's all back together, just need to put water in it. If the leak is bad, my plan is to fashion pig pads in that area.

I've had better luck putting those timing cover gaskets on the engine side first using the pins to locate them and then putting the cover on. The aviation sealant over time thickens up a bit in the bottle, I forget it is on the runnier side when fresh which wouldn't help here.

This is now becoming comedy. The test fire yesterday actually seems to indicate no leak at the crank seal and no leak at the front of the pan although I haven't been back out to check the pan this morning. 

I was running on that little high yesterday evening when the new jets I ordered showed up. I decided to bump up both the idle and main jets as it seems as clear as it can be that, if anything, it's been lean. I got to the first main jet of the rear carb and the jet didn't want to stay in the emulsion tube. I figured, eh, I'll get it right over the hole and even if it falls out it'll just drop in there and I can seat the emulsion tube onto it.

Well, it did fall out and into the hole.

Upside down. 

So after a few minutes of trying to fish it out with some safety wire, I pulled the carb off and dumped it out into my hand.

I've got a very busy work day today with my last meeting starting at 7PM so somewhere in the middle of all that it'll be packing up the truck and prepping to leave tomorrow for Schenley.

Schenley year 5 in the books and our highest finishing position yet at 7th! Internally I was shooting for a top 5 spot but all things considered, I'm very happy with this. How did we get there?

I try to get to the park around 10AM on Friday giving me plenty of time to get my paddock set up, car through tech, BS with vintage racing friends, etc. Apparently there was a big wreck on the turnpike that I got off to avoid and some traffic getting on to 79 but I rolled in around 1045.

I was through tech easily in the early afternoon, spent time cruising the paddock catching up with people then headed over to the AirBnb to clean up before the driver's meeting. I came back and shot out for the course walk to bring a friend some water. It was HOT and his wife said he was hurting for some hydration. This was also his first time at Schenley so I completed the rest of the walk with him, providing pointers where I could. I hadn't decided whether or not I was going to the driver's reception so I just hung around with friends. There was also a long traffic jam getting out of the paddock for the parade. Still have no idea what happened with that but I wasn't in a rush to get in line. By the time I decided to go, the parade was long gone and I had no idea where I was going. The volunteers told me to go to Phipps and I couldn't miss it. Well, I did miss it. I got up to Endless and knew for sure the party wasn't up on the golf course so I turned around and came down. 

On the way back down the hill it was clear that one of the rear brakes was sticking something fierce. I did finally find my way to the reception, parked Hatchet (last in the line) and headed in for some food. Lines were super long so I grabbed something quick and went back out to take Hatchet back to the paddock to figure out the issue. I was greeted by a huge puddle of water coming out from under the car. Sweet.

The left rear was hot hot. Figured the piston must be sticking. I didn't have my tool with me so a buddy let me borrow his channel locks and I screwed it back it. Turns out, that was the fix. 

The coolant leak was one of the caps I put on the transfer tube where coolant used to come back in from the intake. Double fixed. 

My group was first out Saturday morning and, although I wasn't pushing, everything felt good and I was 4th quickest for the session. I believe my time was a 2:27. At one point though, going into the Fountain, my throttle stuck wide open. I was able to woah the car down and shoved it into third forcing the revs down but, um, that was sketchy. 

After some poking around, I found that the rod ends were super sticky. Don't think they're supposed to stay like that. 

Further investigation found a real ragged edge in one of the sockets where the retaining clip goes through. 

Paddock friends to the rescue again. I was hoping for a small file to remove that burr but a friend had misc original rod ends and bits and bobs and I was able to piece together a new rod.

Our afternoon session was very, very wet and was black flagged early on for an 02 that went straight into the jersey barriers at Phipps. Sitting at start finish during the black flag, I noticed temp was slightly over half which is unusual at idle but when they sent us out, I went out with the group. All told I probably got 3 full laps including the out lap and came in qualified 10th. Rain had been threatening but I decided to stay on the Hoosiers and, although my wife brought it and asked me a few times if I wanted to use the RainX, I didn't. With those factors, I was disappointed but figured, oh well that's where I am.

As I was rolling down the paddock I noticed that temp was very, very high. Turns out, I had lost about 2/3 of my coolant because the replacement cap I used had popped as well! The cap on the other side was going to pop in short order as well. 

At least the brakes were good! I let the car cool down and ran a length of fuel hose between these two barbs, getting rid of the cap situation. An 02 buddy of mine showed me his cooling setup that he's been running for season after season. It totally removes the path out of the water pump to the back of the engine as well as the t-stat and he's never had an issue with it. I'm probably headed in that direction. 

Saturday morning felt good. I only ended up with 1-2 clear laps and turned a 2:24. Not where I was last year but everything felt good so I wasn't complaining. Later in the morning an announcement went out that, since our quali session was such a mess, they were going to grid using a blended time, placing me 7th on the grid.

I had the pointy end of the field directly in front of me, a fast Alfa behind and another E21 with an M50 engine in it behind the Alfa. I hung with the pointy group for the first lap but going through turn 1 a second time, right on their tails, they just all disappeared over the hill. That hill is my nemesis at Schenley. I feel that I carry good speed where I can and have actually gotten compliments on how I carry through turn 1 itself but I just don't have the power to stick with the quick cars up that hill. At about lap 4, I had fallen to 9th with the Alfa and the M50-powered E21 getting by me. 

Less than a lap later, I catch the tail end of the E21 going straight into the jersey barriers at the Fountain. Spectators and corner workers alike were still scurrying. That corner is more difficult than it appears on the surface. You are carrying considerable speed out of Phipps, have to cross over the crown of the road either under braking or right after and then dive down into the corner. It's no joke. He was totally fine physically but what this meant was we had a huge yellow section for the rest of the race as the car was unable to be safely moved totally off track. 2 laps later I passed a B who was off track after the hay bale chicane putting me back in 7th. 

Unfortunately, we ran the last two laps under full course yellow. Not the way you want to end a race but, hey, I'll take it. I wasn't going to catch the front runners but I was in absolutely no danger of being caught by the cars behind me. 

I still haven't seen times from my Sunday morning session but I don't think I bettered my 2:22 from last year during that session and my quickest in the afternoon was a 2:24. So, because of things specific to my sessions and out of my control, I didn't really get a chance to push the car consistently through the whole track to compare performance to last year. 

Elmore did his thing to and from and we got home early evening yesterday. 

After unloading, with my family out to dinner, I was drawn back to Hatchet for a celebratory beverage. 

Despite the headaches I totally love this car and leave this weekend very satisfied. I didn't hit my goal of a top 5 finish but I continue to climb up the finishing order and feel confident that we'll get there. 

It was good seeing your car pop up from time to time in the events instagram feed over the weekend, unfortunately always from the drivers side so no good exhaust sounds. Congrats on getting it there and through the event.

Did the E21 with an M50 have a 2.0 litre in it? I didn't realize they came that small but they did in Europe. Seems pretty cheaty lol

In reply to adam525i :

The exhaust is on the wrong side to be heard while spectating at Schenley for sure. My wife took some video and the car seems totally silent unless there are no other cars around. Kind of funny. I'll see if I can get one of the videos she took uploaded. 

EDIT:

It's got the 2.4 in it. This is the son of a long time competitor and, although I don't understand the rationale, the dad said the race directors wanted him in a slower group so he wasn't chasing the faster, over 2L cars. I also had no idea there was a baby M50 sold overseas. 

Hatchet is tucked away for the winter. 

When I was pulling off the Hoosiers to store them indoors I noticed something. Check out how narrow they are compared to the 195 Falkens.

It's no wonder I end up with too much heat in them 2/3 of the way through a session. These are Hoosier TD-R 22.5x6x13.

The Diamond wheels are 13x6 and I think the TD-R 22.5x7.5x13 are probably going to look like balloons on them so next season I'm thinking I'll move to the Speedster in a 205/60R13. The next step in development would be moving to a 13x7 inch wheel.