Christopher smith

Sorry but did not label correctly- it is the old rusty one that had a leaking slave cylinder after 5-6 years of mild use. I was just trying to show the snake sort of route the -4 flex line takes. It worked fine and the 2 person pedal bleeding technique was easy originally but I have tried all sorts of bleeding methods with the new set-up. No bubbles seen now but still get that grinding noise after 8-10 starts , when bellhousing is hot. I hope to have the engine out this week to see what could be causing the noise. What does seem strange is that With the pedal down and clutch disengaged I can just reach a finger in there through the side port and can turn the release bearing with mild pressure. Not as easy to turn as when clutch pedal is up but I would think the pressure of it pushing against the pressure plate fingers would keep it from turning . The bearing, slave cylinder and the pressure plate are not getting hot, just the bellhousing.

Thanks guys---I did have some trouble with the 2 new master cylinders and the pedal would not come all the way up.. The threaded push rod Tilton used in the new ones was about 5-6 mm longer than my original one. I found that it made the pedal hit the frame when in the up position so had to shorten it, otherwise trying to bleed the system was not pushing fluid into the line. I guess the piston was covering the port. But fixed that so in the pedal up position there is more than 7-8 mm clearance from the frame so the piston retract fine now.. I have an adjustable pedal stop and tried a few distances from firewall so as not to push the slave cylinder piston out of the housing but to allow release part way to the stop, maybe 20 % of pedal travel or 50 % of travel adjusted differently ( did not help). I can visually observe the effect by how far the release bearing travels when the pedal is depressed.( I was also wary of pushing it too far and making the pressure plate fingers scrape the clutch discbut it does not look like that could be the case..Both times coupling the engine to the bellhousing, it just required minor jiggling to line up but no force once the trans input shaft found the splined center of the clutch disc. I did not undo the pressure plate but maybe should have but it had worked fine for years so saw no need. I guess I need to pull it all apart to see what is scraping.

MV8--- Gave it a try. About 10-12 starts then grinding noise started again when trying to put it into 1, 2 or R, so shut it off. Then put it into 1st, pedal down to stop, ignition off ( and also tried 0n), hit starter- no movement at all, no grinding noise either. repeated all this again-same. Adjusted stop up a bit- same So I guess if I might need to take it all apart so I am not risking much if I trash something driving it. The tough part is hooking up all the motor mounts, electric, oil cooler and accu-sump lines, radiator hoses etc..Seems to drive ok , no noise once pedal is up and car moving

MV8---Thanks for the detailed analysis. My pedal has a stop that is adjustable and I have tried to set it just a bit past the point of release but also tried it set well past the point of release.No difference in stopping the grinding noise issue unfortunately. I can observe the release bearing travel and even touch it through the side port where the fork would have gone in , but is no longer there. I see the release bearing travel has been the same cold or just after a series of starts and that grinding sound with the clutch pedal against the stop, when trying to put it in gear. I guess I will try one more time with vacuum bleeding out the bleed port before I give up and yank the engine again ( a pretty tight and complex job with a 1500 in a series 1 frame and oil cooler lines etc. needing to be dealt with). perhaps I will find some damage or old oil contamination on the clutch disc that, rather than making for clutch slip might make it grab when hot? Seems to work fine for a few starts. I had overfilled the engine oil last year and had some slip past the rear main seal but not sure how that would have gotten onto the clutch disc and never had clutch slip issue.

Tried another couple of bleeding methods including an extensive reverse pressure bleed feeding a lot of fresh fluid up from the bleeder to the master cylinder. No bubbles at all. and no change in how the slave/release bearing works. It still makes the awful grinding sound trying to put it in a gear with the pedal full depressed but only after 10 starts. I can see no change in the slave cylinder or release bearing movement and it looks like it is pressing against the pressure plate fingers no different before about 10 trial starts or after them when the bellhousing is hot and the noise starts. It does seem strange that I can easily turn the release bearing with light finger pressure when clutch pedal is up and with a bit more finger pressure when pedal is down -(not expected) and it did not get hot. I am getting set to yank the engine again since the hydraulic part seems fine. Perhaps I damaged the clutch disc or pressure plate somehow earlier when I reinstalled the engine but why is the noise only when hot or after some starts?. Any thoughts are much appreciated.

Great video! I keep hearing just how crazy the clutch hydraulic systems are. I even thought that maybe after a few starts maybe the heat in the system expanded and pressurized trapped air somewhere in the line and forced the release bearing too far so it pushing the pressure plate fingers into the clutch disc thus keeping it from releasing. I would think that would give the symptoms I have experienced. Not sure if that could happen. But ,in any case, a better fluid bleed sounds like it might fix it. I think I can set up a pressure feed of clutch fluid up through the bleed port and through the lines up to the master cylinder. But I will try that method in the video first. I hope something works.

MV8----Thanks for your valuable info to solve my "Saab Story". Still wondering how I had it working fine in the same exact configuration for years, albeit light usage except some really fun test laps at NJMP. I guess I will still try to get the last of the air out somehow ( reverse bleed?) before I take the next dreaded steps of pulling the engine again to get at the plumbing.

Many thanks. I think I may not have done the bleeding thoroughly since the plumbing had to take a circuitous route in the original install and my engineering friend has passed away since. Probably not as bad as the rear engined race car he did. I made various attempts at the old 2 person method and tried vacuum bleeding from the remote bleeder and also pressure bleeding at the master cylinder. All of those methods exited at the remote bleeder so flow was long downward before 2 upward runs and I guess that trapped bubbles. I am thinking of back flow bleeding if I can set up for it. I have attached an image of the old slave cylinder that had leaked but worked fine for some years after a conventional 2 person (pedal pump) bleed, so I guess I am doing it wrong. Still wondering about the mechanism that could explain why the clutch actuation is fine for 5-7 starts and then not.releasing.Could air in the line do that on heating maybe? I should have stayed awake in my thermodynamics P chem class. Sure appreciate your guys thoughts.

Clutch action was fine for 5 years of light use, but concentric slave cylinder finally started leaking. It is a Saab 93 type slave set-up (from Bean Engineering) coupling my 1500 pre-crossflow to a pinto 4 speed using a Tilton pedal and master cylinder set-up with -4 Earl's lines in my tight clearance 1959 series 1 frame. So I had to pull the engine to get at it but not the trans, to replace the concentric slave cylinder and I replaced the master as well. The clutch works fine as I test it up and down my driveway about 5-6 starts. Then I get a frightening grinding sound trying to put it in any gear with pedal fully depressed at a stop. I have adjusted the pedal stop back and forth to no avail. Reaching in through the old side port in the bellhousing I can see the release bearing and it just touches the pressure plate fingers, but I can rotate the release bearing with my finger. The bell housing seems warm but not sure why it would work fine for years and then when replaced, work fine at first and then fail to release after a few start-stops in the driveway. If you click on the image you can see the release bearing. Any thoughts or ideas most appreciated, particularly if I do not have to pull the engine a 3rd time.

Anyone have advice for a foot rest design? Really tight footwell on my 1959 series 1 even with my size 9 shoe. With RHD my foot is within a few mm of touching the trans tunnel when on the clutch pedal. I can work the pedal OK on this Tilton hanging pedal assembly. So maybe rivet or bolt a small metal angle piece to the floor just aft of the unpressed clutch pedal? What does Caterham use-approximate dimensions and location relative to the clutch pedal?

They meant to say Dartford not Darford. Looks like spellcheck struck again.

There were several changes from a series 1 like mine to a series 2. Not sure why the changes were made as I do not think the total weight dropped. The steering rack was farther back , behind the axle. The column has 2 universal joints with one at the rack and another about 1/2 way back to the steering wheel. Not sure if that makes a difference in a major crash. The rear suspension had 2 outer links on each side of the axle rather than the central pick-up and I assume that was when the cracked housing issue started, or was it better traction tires that caused the cracking? I assume the couple of diagonal frame tubes by the driver and passenger knees were removed to save weight but could not have been much. Any explanations that make sense?

Just a thought- Some of the books list the axle on series 1 as BMC Nash Metropolitan which is virtually the same as Sprite and the A40 I have so you may want to show that as a choice since some may not have been sourced as A40. Thanks for the efforts!

My series 1 #475 still has the original 4.22 to 1 axle that was from an Austin A40 that had the suspension attachments done at the Lotus factory ( I have the receipt for the work- really cheap back in 1959!). It is the same as an early bugeye Sprite and Nash Metropolitan and these were used for quite a few series 1 cars from what I understand. Probably lighter than the newer variations and the suspension does not attach under the center like series 2 (that apparently is a major failure point if highly loaded). I do not have LSD or the double bearing modification that many racing Sprites used.

I looked around for info and see that some makers of mesh caps claim 2 or 3 layers of stainless mesh with what may be a paper filter layer sandwiched in between layers to trap finer particles. They claim no restriction but I find that hard to believe. I also went to the McMaster Carr website to see their offerings of mesh which gives nice detailed info on wire size, wire configuration and a calculated open area for quite a variety of mesh offerings. When I can get to it I will measure the actual ID of my velocity stacks inboard of the wider area where the mesh caps attach to calculate area and compare that to the somewhat larger area of the mesh and add that to the extra area provided by the mesh side openings since the mesh is "belled out" a bit. I can then put a micrometer on the wire and maybe count the wires per area to calculate open area to compare with the smallest cross section area inside the velocity stack. Probably a waste of time but now I am curious. it would be great to see dynamometer data if anyone has it as that is the real test and sorts out any peculiar aerodynamic effects within the ports as well as within the carb throat and the stacks and a filter or mesh screen.

I guess the reduced throughput of a screen is the reason why the ones for velocity stacks always are always rounded out to give more surface area. Maybe not enough however. Not sure

Does anyone have any dynamometer or other actual flow data on the stainless mesh or for that matter any air cleaner types? What were the cars out front for all those years in D Production using for their 1340 and 1500 cc powered pre-crossflow cars?

I recall hearing that the short velocity stacks are optimum for high rpm while tall ones are more for torque at lower RPM.Not sure if this really matters much.

I have the stainless steel mesh type on my 40 DCOE2 velocity stacks. Not sure they filter out much except nuts,bolts and stones. And the rubber attachment rings seem a bit shaky. So can not recommend this type for higher mileage use particularly in dusty situations. But I see claims of better performance from other mesh air horn units. I recall seeing the oval track sprint car guys running without any filters or mesh and wondered how many rebuilds per season they must do.

Craig- I followed the old Vizard book for substantial combustion chamber modifications and ports on my Cortina GT sourced 1500 pre-crossflow. I was curious how the Cosworth motors differed from this when supplied back in the 1960s Super 7s. Was the Cosworth approach very different from stock Cortina GT? hanks-Just curious

It has been many years since I was there but I think I stayed in Bologna and commuted by train to Imola. I walked a lot around the track and for the race I was on a hill on the outside of the track that overlooked the last couple of turns before the pit straight. Pretty crowded. Not sure you can still do that on a general admission ticket but worth checking. Train service is great in Italy unless you get off at the wrong stop in Monza like I did a few years ago. I should have just followed the crowd. Have a great time!

I enjoyed the movie and the way the cars sounded- not sure how they did that but the originals were some naturally aspirated 4 cyl and some v12s so somehow they got great sounds spliced in. Do watch for the downshift to go faster on a straight section and probably more side by side racing than really happened, but otherwise OK. I would also really recommend finding the movie "Ferrari -race to immortality". In this 2017 full length documentary type movie they have many great clips from the original GP and pro level sports car races from late 1950s just before most went rear engined. Of course there were lots of tragic crashes back then and the movie did interview some of the drivers pre-crash and relatives and other drivers post crash. No Hollywood plots or fake stuff but somehow great photography preserved (enhanced?).

Great work!

MV8's comment about the wobble allen is spot on at least for initial tightening. I was worried it might round off in final tightening however, and that is when I cut off part of the short end of a conventional allen to allow final tightening. Also, someone before me installed a 2 ended stud at one point in the head which allows for holding the gasket in place easier. It then takes a 12 point flange nut ( McMaster-Carr sourced) to clamp the full assembly down. I managed to refit the whole intake + 2x40 DCOE assembly at once but that may be trickier than first fitting the headers, then intakes and then adding the carbs and finally linkage. I never had a manual so it took a lot of guesswork to figure it out. Now with access to a manual for series 2 I will look and see the "professional" way to do it.

Happy to help with some ideas just contact me when you're ready. I have been through it several times