Healey 100 issues

I recently started working on this car (new to me) and chose to fix some small odds and ends. I did basic vehicle maintenance and fixed some minor leaks and just cleaned the car up and showed some proper TLC towards it. Prior to me showing some attention to the car, I noticed that the car had a really rough time taking off from a dead stop. It is extremely jerky and hard to modulate throttle unless the clutch is slipped a little to make the engagement an acceleration as smooth as possible. In part to doing maintenance I opted to rebuild and clean up the carburetors with a kit from Moss Motors, the carburetors were then reinstalled and balanced and the car idles pretty smooth for its age changes. The car is not stock which makes diagnosing this particular problem a little more difficult and the fact I am not to familiar just adds to it. The car has .040 over sized forged pistons the camshaft is ground and nitrated with the final specs being .270 degrees of duration and .280 degrees of lift. The car is outfitted with an early 3000 BN7 or BT7 series transmission with revised ratios and overdrive. I am open to any help on this since at this point the only thing left would be linkage from the pedal to the carburetors and the movement of the motor on take off. Thanks and I hope for a first post I am not going to be flamed!

Welcome. The good news is nobody gets flamed around here. Do you have a 100/4 or a 100/6? Here's the cam specs, courtesy of Mike Salter, for the four cylinder cars:


>
> 100 cam specs:
> Lift 0.390"
> Timing @ 0.021" 5, 45, 40, 10
> Duration 230
>
> 100M (and S) cam specs:
> Lift 0.435"
> Timing @ 0.021" 10, 50, 45, 15
> Duration 240
>
> IMHO cam profiling has come a long way since the days when these were
> developed and there are better profiles around now.
> In our Targa engine we are running 0.485" lift
> Timing @ 0.021" 49, 77, 77, 49. Duration 306 This engine still pulls
> very strongly from 1200 RPM.

Lift is measured in inches, not degrees as you have mentioned. What kind of cam is it and where did you get your specs? Does it idle smoothly or is it lumpy? If you have a hot enough cam, it's possible the nature of the beast is that the car is going to need to be revved a bit at take-off just to launch it.

The Healey's throttle linkage is crap, though I will admit that it's been decades since I've worked on a 100's (4-cyl) linkage, being much more familiar with that of the six-cylinder cars. So making sure it is in optimum condition would be paramount.

I'd also recommend that you take a good look at the engine mounts, both the rubber isolators, buffers (if fitted to a 4-cyl?) and the pedestal bases themselves. The trans mounts should also be inspected (and are far easier and cheaper to replace) as well as the tie-rod that limits fore/aft movement.

Few parts on a car__any car__degrade faster than those made up of bonded rubber, and getting oil and/or grease saturated hastens the process.

Referring back to Rick's comment, and giving it more throttle when setting off will add to the load imposed on the engine and xmsn mounts__and I'm all in favor of a good, strong launch__so you'll want them to be in good condition anyway.

Thank you both for some of your help and insight. Things I have done since my initial post have been check pinion angle and correct it. The pinion angle was found to be -1.5 degrees nose down which from my understanding is not good. Leaf spring wedges were not installed which leads me to believe that someone before me removed them. Wedges were installed to correct the nose down and bring it to 1.5 degrees nose up which I still think is to much but I did what I could with what I had and I may change it at a later point. I removed the engine cover and test drove the car to see how much and if the engine is moving enough to affect the throttle linkage. Upon that test drive from what I could see the engine does not seem to be moving around abnormally like it has bad engine mounts. I inspected the transmission tail shaft mount and that also seems to be in good condition and fairly new, so again it looks as if someone was in here trying to fix the same issues I am currently experiencing. I did notice that this motor does not have the tie rod installed to prevent the engine from fore/aft movement. Because of the time of year (Wisconsin winter) I was working on the car I was not able to test drive it before some maintenance was done. The transmission was removed and clutch was inspected and deemed ok to reinstall back into the car after some oil leaks were fixed. The clutch disc and assembly did not have any oil contamination either, it did look fairly new along with the pressure plate and flywheel. Regardless of appearance and overall condition is it possible that the clutch disc has weak damper/cushion springs allowing the drivetrain to have an abnormal amount of rocking type movement in the drivetrain? If the clutch is slipped very gently with power being applied in a linear fashion the car seems to take off fairly smooth. If the car is driven like a modern manual car where things happen a bit faster in a shorter amount of time that's when the jerkiness is at its worst. If the car is somewhat gently launched and full throttle is applied there is no jerkiness. I am trying my best to not over think this and keep it as simple as possible but I feel my lack of experience with how these cars drive and work is my biggest issue. I don't know what's normal and what is not so anything thing I find I have to use my best automotive judgment. Again, any help is greatly appreciated!

Hey Randy, if you think the 100 throttle linkage is 'crap' count your blessings that you don't have to deal with a Right hand steer car!
Regarding the engine mounts, I have only found replacing the rear mounts under the overdrive to be beneficial because they suffer from oil contamination. I replaced the front mounts but could not notice any difference, even though the old ones were as hard as bricks.

G'day donnie_leo26, I suggest that when you install a tie rod you will notice a huge difference. Because the 100 has a mechanical clutch operation the tie rod is vital for smooth clutch engagement. The tie rod was absent on my 100 when I bought it many years ago. Because parts weren't then available I made up a rod using threaded bar, locknuts and large washers. Also used shocker rubbers. The difference in drivability amazed me!

The tie rod bushes are subject to rapid deterioration due to oil contamination; urethane bushes are available from the Usual Suspects.

Also the original clutch linkages are a bit ropey. The upgraded parts avaialable are a great improvement.

I am assisting my friend in reassembling a 54 BN1 that he bought in pieces 10 plus years ago. We just put the engine back in (not a lot of fun there) I am curious regarding the mention of the Engine tie rod to control fore and aft movement. I do not recall that we had such a piece to install. Looking for it in AHS and Moss to no avail. Where does this piece fit. Any information would be greatly appreciated

Joe,

You will find the tie rod connects the end of the overdrive to the chassis. You will need to go underneath to see where it goes. If you check out the cruciform between the main chassis rails just about where the overdrive ends you will see a large hole in the chassis cross rail. The tie rod fits in here pointing front to rear and connects to a matching loop cast into the overdrive/gearbox casing. Hope this makes sense I don't have a picture of that area handy.

If you look at the AHS catalog/web page its part number 23 under the three speed gearbox section.

Just popped out to get a photo. Unfortunaley the car isn't very accessible at the moment so the picture doesn't show very clearly location but the picture is taken from underneath the right hand side of the overdrive facing backwards.

Steve
Thanks for the Quick reply. From the discussion I thought it was attached to the engine. Never thought to check out the OD connection. He prob has the part lying around in the pile.
Pretty sure he has not installed this part.

Moss shows the parts here: https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28886&SortOrder=90

Unfortunately, they don't carry the tie rod itself but it appears to be a long 'stud' that may be available elsewhere if you can get the specs/dimensions. And, not only would this part contribute to smoother shifting, but it's necessary to keep the fan from contacting the radiator in a hard stop.

I just spoke to my buddy and he has the rod but did not know what it was for. He needs to get some bushes.
And there was a big OH yeah there is a hole in the back of the OD unit.
Thanks again

Sorry I haven't posted here in a little time, I did however fix the problem I was having. The engine mounts and buffer mount were the reason the car was having such problems. They were installed incorrectly (some how) and the weight of the engine was resting in the buffer mounts and relying on those to soak up vibration and movement. Once I replaced them and have them installed correctly the car drives normal which is a relief. I am still missing the tie rod but I will make something up with some left over metal and rod ends that I have around. Thanks again for your guys help and advice, I really appreciate it!

Glad to bear you got it working well, despite what some of these guys say, the 100 can be a pretty smooth driving tourer. I had the stock clutch and throtlle linkage, very well broken in, and other than some initial adjustment to the throttle linkage never messed with it in my ten years of ownership.

Always was an easy clutch to use with the torquey 4, even after I lightened the flywheel.