I recently acquired my father's 68 FHC, 2+2, automatic. After sitting 33 years, the car fired up with fresh gas in the carbs and new battery. I removed the gas tank and had it cleaned, replaced the plastic fuel lines with modern rubber, replaced the fuel pump with a low pressure modern pump, and I just removed the twin ZS carbs for rebuilding. The carbs were in surprisingly good shape. The float bowls have just a smidge of varnish, nothing like I expected.

I want to make the car a reliable driver and keep it as original as possible, but replace unreliable bits such as fuel pump, distributor, etc. For example, I know that wider better wire wheels are available but I want to keep the original wheels, but I'd replace the brake lines with braided steel if it makes the brakes better.

I have some questions.....

1. bypass valve - the twin carbs have a bypass valve on the front carb only. I looked online and found some carbs each with a bypass valve and some with only one. Why would they only have one on one carb?

2. air box - the large factory triangle airbox appeared from 1961 to 1969 and had air horns that were aimed right at teh engine block. In 1970 the E type had a much smaller box with the air intake higher up. I thought that if I got the 70 air box, a hose could feed cold air to the carbs. Thoughts on this?

3. glass sediment filter - I cant remove the glass bowl from the top. Any techniques to this?

4. spark plug wires/distributor - spark plug wires are shot...cracked...50 years old. I have seen price ranges from about $50 at local auto parts stores, to $200ish from XKs unlimited and other Jag places. Thoughts on quality wires? I am planning to install an electronic distributor...thoughts on this as well?

5. heated intake - Jaguar went to great lengths to heat up the intake manifold with the large cross over from the exhaust and coolant in the intake. Is it better to remove the cross over and block it off with block off plates from a 69+ and block the coolant passages for a cooler intake charge? I havent read of anyone doing this.

Any tips to improve the car, yet keep with its original character are much appreciated. For example, Weber carbs are a boost in power but are expensive and not original to the 68(also triple SUs). But removing the secondary plates are something I will do because its free and improves driveability.

 

I have been through most of this with my 68. Here are some thoughts.

1. I had the bypass valve on the front carb only and that is how it was originally (I am the original owner).

2. Whenever I made significant changes to the air induction it degraded performance and I ended up undoing it. Jaguar seems to have spent some attention on getting it right.

4. Choose a distributor before you buy leads. Some use push on lead terminals, some screw caps and they have their own lead resistance requirements. Also, consider whether you want vacuum advance. In 68 it was not used but after your other changes, you may want it. Whatever you choose make sure the centrifugal and vacuum advances are close to the original. Jag maintenance manuals have the data listed. Your current carbs do not have a vacuum port so that option is only if you do something drastic. See below.

5. If you are keeping your Strombergs, get rid of the crossover. To maintain an original appearance, you can put aluminum plates under each end of the crossover. It is easy to cut and shape aluminum to make the plates invisible. I did that and drilled a small hole on the underside to relieve any pressure buildup. Then remove the secondary butterflies as you plan to. I also removed the spindle and made sure the holes were plugged and sealed well. After doing all this your mixture will most likely be much too lean and some minor mod to the carbs will help alot.

If you can handle the cost and the effort, converting to triple SU's and adding vacuum advance will give you a dramatic improvement. SNG Barrett sells an all inclusive kit with newly manufactured carbs and manifold. Even after I finally had the Strombergs running well, they just do not offer adequate flow. I consider the time spent on them to have been an education but otherwise a waste.

Good luck with this.

 

Thank you for the responses to the questions. I do plan on keeping the Strombergs, as the triple carburetor setup is very expensive. When I was installing the rebuilt Stromberg carburetors, I noticed that the intake manifold Port is two in. In diameter which would accommodate some 2 inch carburetors nicely. It makes me wonder if two of the triple carburetors would bolt up to the twin Stromberg manifold.

In any event, I fired up the car and it ran well. The throttle sticks some so I've been fiddling with the linkage. It's clearly a linkage issue. When rebuilding the carbs, i also removed the secondary butterflies and disconnected that linkage from the carburetor linkage.

While the car was running after a couple of minutes, some water dumped on my right foot. How do I get access to the coolant hoses on the dashboard side of the bulkhead?

Also, there is a large metal tank near the oil filter with a hose running to the intake manifold and then one going to the bulkhead. What is that tank?

 

That is what is called a "Reservac Tank", and provides a reservoir of vacuum for the brake servo. The little valve that screws onto it allows the inlet manifold vacuum to create a vacuum in the tank but is one way so if the engine stops, you'll still have vacuum to the brake servo. The other pipe runs to the servo. If the engine is not running, or the inlet manifold has little vacuum, (like on full throttle), the vacuum in the tank normally allows a few brake applications to be assisted before the vacuum is exhausted.

 

Thank you for the responses to the questions. I do plan on keeping the Strombergs, as the triple carburetor setup is very expensive. When I was installing the rebuilt Stromberg carburetors, I noticed that the intake manifold Port is two in. In diameter which would accommodate some 2 inch carburetors nicely. It makes me wonder if two of the triple carburetors would bolt up to the twin Stromberg manifold.
I owned a 68 2+2 for 20 years. I agree with Bill on Strombergs, They are not "Jaguar performance", and frustrating to keep in tune: The 68 carbs had a fixed needle and a fixed jet, so other than new parts, you have little you can do, even a minor leak in spindle shaft seal, will not permit a proper tune. Very important to set fuel float level correctly, both carbs matched. I have attached an aftermarket adjustable jet picture and source that will solve the too lean issue as you make changes to induction system. I went all in and did three Strombergs on a 420 triple manifold to get by the performance limitation.

In any event, I fired up the car and it ran well. The throttle sticks some so I've been fiddling with the linkage. It's clearly a linkage issue. When rebuilding the carbs, i also removed the secondary butterflies and disconnected that linkage from the carburetor linkage.
You may have lost some return spring action by disconnecting the secondary throttles. I had stiffness on my 3 overhauled ZS and added a external return spring and link from a SU carburetor (XKE ser 1).





While the car was running after a couple of minutes, some water dumped on my right foot. How do I get access to the coolant hoses on the dashboard side of the bulkhead?
There are some water pipes under the Dash cover going from right to left then back into engine bay. The Dash cover has several bolts on each side by the window post and in the center from memory there wires/lamps needing removal. If it is the water pipes, they are available in SS for a permanent repair.
Rgds David

 

You have some good responses from others. David's photo is quite interesting. You can modify your Strombergs to richen the mixture. I added a shim to each carb throat which raised the piston. After some experimenting, the improvement was substantial. Even though it ran smoothly, a dyno test was very disappointing which got me to spring for the SU's.

I have not had to do it but I believe you need to remove the top of the dashboard to access those water lines. Maybe others have some ideas. I think before you go much further, you should buy a maintenance manual from SNG Barrett or one of the other suppliers.

 

More good info. I'm familiar with the adjustable Jets from Joe. At around a hundred bucks each it's a bit stiff but possibly worth it.

I started to remove the top of the dash in anticipation of getting access to the offending hose. I am wondering if I could bypass the heater for the time being just to test the rest of the cooling system and then replace all the interior heater hoses a bit later. Can someone show me pictures of exactly what needs to be bypassed from the engine side? From what I can see, on the passenger side in my LHD car, the input from the intake manifold would be disconnected from the bulkhead. What I can't figure out is which heater hose do I connect it to on the driver side as there are two hoses that go into the Bulkhead from the heater.

there seems to be multiple issues with the carburetor linkage. One of the first things that helped was the accelerator pedal was rubbing against the carpet. I bent it away from the carpet about a quarter of an inch and that seemed to help a lot. I also lubricated all the joints but there is some play on the passenger side linkage that attaches to the bulkhead. I'm considering installing a return spring on the front of the front carburetor to possibly the disconnected secondary linkage which should help the throttles return back more sharply. I was still having this problem when the secondary butterflies were connected so I don't believe disconnecting was a problem.

I have a Haynes manual that I got from the mid-80s when my brother and I rebuilt the motor.


UPDATE... after Consulting the aforementioned Haynes manual on page 264 it looks like that number 45 and number 26 get hooked together in order to bypass the entire interior heating system, correct?

 

A sticking throttle linkage is often caused by old engine mounts. The rubber deteriorates and that drops the engine about 1/4" and then the throttle linkage sticks on the engine frame. Check for clearance at the frame and if it is close it may stick there occasionally. Replacing the rubber engine mounts solves the issue or you can add a few washers as spacers to regain the needed clearance.

 

UPDATE... after Consulting the aforementioned Haynes manual on page 264 it looks like that number 45 and number 26 get hooked together in order to bypass the entire interior heating system, correct?
Yes, connecting a hose from # 24 to #45 will work . I ran without a heater for years, but left the pipe flow intact as it provides some heat for demisting the inside windshield. I removed heater core #8 and connected the two pipes together there. I did change both Pipes with new SS units.

 

I will check the linkage for rubbing but so far, I dont see it rubbing. it seems to stick on the very last part of the rotation just before Idle.

Regarding bypassing the heater core, I remove those two hoses from the bulkhead couplers and one of them was pretty severely rusted so it looks like SS Lines will be in my future. I'm trying to remove the lower hose from the long metal pipe that attaches to the front of the car but I'm having a devil of a time having access to it. Once I get that removed then I will just run a rubber Loop for a while until I replace the interior lines with SS. Any hints on removing the dash to have access to the interior metal pipes?

 

4. spark plug wires/distributor - spark plug wires are shot...cracked...50 years old. I have seen price ranges from about $50 at local auto parts stores, to $200ish from XKs unlimited and other Jag places. Thoughts on quality wires? I am planning to install an electronic distributor...thoughts on this as well?
To match your new electronic distributor you will need modern resistance wires. If you ask you local auto store for 1968 car, you will not get what you want. Ask for 84 XJ6 and you will get plugs and wires options that will match your new Pertronix distributor. I used NGK 7327 BP5EY V-Power Plugs (they may have to order, usually a one day wait) you'll want 8 as you want spares for your boot kit. If you drop one, it will not be reliable. BECK/ARNLEY 175-5073 wire set works well and is reasonably priced.("push-on" not screw on terminal ends) Every Jag owner has their own favorite Mfgr.
There are 3 distributor options from Pertronix, all fit, but two require Vacuum sources ( one is just replacing points, the other is high performance.) I retrofired my center carb with 1/8 x 10-32 hose barb, as it was already drilled and tapped. The simple option is to get the one with mechanical advance only like your current distributor. (XKs web-site has specs on all three. You will want to get the ignition coil that is specified for the distributor.... does not have to be pertronix coil, but the coil specifications need to be the same if you prefer a different Mfgr.. Plugs, Wires, Coil & Distributor once you have decided, shop around for a sales Amazon, E-bay all have reduced prices at times. Installation is Plug and Play. Rgds David


Disconnect #12 at top and see if the throttle stiffness is before or after. Also disconnect the link to the auto-trans kick down assy to see if the cable #18 is binding. The idle return springs on the throttle shaft are at there weakest during the last bit of travel... new springs or as I did add one more return spring to throttle shaft ... Where you removed the linkage to the secondary throttles is a link that should work, you may have to remove and put it back 180* out to get it in correct position to added a spring. Rgds David

 

You can also disconnect one carburetor at a time with the zig-zag fitting that connects the two shafts to the lost motion link. If you changed the butterflies, one may be contacting the side of the Carburetor throat before being fully closed.

Just another thought: before you do extensive road testing, you may want to increase your AAA towing from 5 miles free to 25. Also copy the towing instructions from your manual and keep with the car, as the tow truck driver has probably never seen a Jaguar up-close. They may come with the flat bed rig, but they can do damage winching it up or chaining it down. Rgds David

 

thank you thank you for the great information on the ignition system David. After I tackle the cooling system, the ignition system is next. I plan to drain the cooling system of whatever the heck is inside and flush out as much as possible. after I get as much of the gunk out of possible with vinegar or citric acid, I will take the radiator out and give it to her radiator shop to either be cleaned out or recored depending on the condition.

My AAA towing is 100 miles. I would like to get this car to the point where I won't have to worry about having it towed. I imagine carrying a full tool kit would be prudent.

 

One additional thought on stiff throttle: there should be some slop in the rigging of the lost motion link so that idle is on the carburetor idle screws not the throttle linkage. The throttle linkage should move a little bit before the carburetor shafts move. The other lost motion direction is to allow choke to open throttle with out pressing on the linkage.

 

XKs unlimited. has a full cooling system hose kit for 68 XKE 1.5 2+2 , chasing individual hoses by P/N is time consuming.

 

You should sign up for there E-mail sales and magazine

XKs Unlimited (parts@xks.com)

Week Three of our Holiday Sale is going on now. Save up to 30% on over hundreds of items for your Classic JaguarSALE! Pertronix Flame-Thrower Distributors Save up to 15%Ignite the Power with a High-Performance Distributor made for your Jaguar! Available for all pre-fuel injection six-cylinder Jaguars.

 

I reviewed the XKs unlimited website and saw that kit. I kind of figured that was the best way to go rather than individual part numbers and hoses.

I'm guessing that the repair I'm guessing that the repair to the cooling system is probably going to be one of the more expensive things I'll be dealing with. I pulled off some more hoses and the thermostat and there is a tremendous amount of rust and corrosion. The nipple on the rear side of the intake manifold is Rusted and will need to be replaced for example. some of the hoses were so clogged they were actually plugged up completely. My thoughts are that rather than having a new radiator put in or a refreshed radiator, and then trying to circulate the bad stuff from the block and the hoses, that it would be best to try to clean out the system entirely as much as possible and then have the radiator done. What are your thoughts on a restoring aseverely rusted and corroded cooling system?

 

Flushing of the block, where all the crud accumulates, is difficult unless the core plugs are removed. Most crude is found at the rear of the block as that is where coolant flow is lowest. I was fortunate in that I rebuilt my XJ engine round an uncracked and bare block mounted on a movable engine stand so clearing out the block was quite easy. The biggest problem is that many owners didn't maintain the anti-freeze thus not having corrosion inhibitors in the coolant.For hot climates where frost wasn't a problem and anitfreeze was not available, owners were supposed to add corrosion inhibitors to water to make coolant suitable for the engine. Corrosion at the head passages can be dreadful in consequence. You'll only know how bad it is when you lift the head. Nowadays you can fill with waterless coolant which is basically ethylene glycol.

 

Unfortunately, the coolant had 33 years to attack the engine so hopefully damage is minimal. the ideal way to clean out all the crowd would be to take the engine apart and take it out and clean all the passages. Have the ability to do that but I very much prefer not to. In fact I prefer to keep the engine as intact as possible and flush out the crud by some other means. I also prefer not to mess around with the freeze plugs or core plugs as they are also called.

In my research to discover the best techniques for flushing out an engine, it looks like power flushing with compressed air and water is a pretty effective means. Also in my research there are a number of chemicals that can be used to dissolve the crud. Oxalic acid, sometimes sold as wood bleach, seems to be a great medium. Obviously care has to be taken to not only dispose of the liquid but to make sure that it doesn't do further damage to the inside passages of the engine or anything else.

Here is my plan so far: put a u shaped hose at the heater input and output of the engine to bypass the heater. Install the thermostat housing without the thermostat. Install the hoses that I removed. Put a mixture of oxalic acid and water into the engine and run the engine with a careful eye on the temperature. The water pump pressure, if it still works, should circulate the acid mixture and hopefully unblock any blockages and start dissolving some of the rust. I figure I would probably do that a few times including draining and refilling with more oxalic acid. There's also a product called evapo-rust which I may use. There's also sulfamic acid which is also used as a grout and tile cleaner. I may use these depending on the results.

Hopefully this loosens up the crud and opens up any blockages. The second round of offense would be to pressure flush the system with compressed air and water. after that I would run a solution of baking soda and water to neutralize any acid and really flush the engine and all the components. Finally if all goes well, the Block & head and all coolant hoses and pipes would be clean. At that point I would take the radiator to a radiator shop to valuate its condition and either have it flushed out or repaired. Of course all hoses would be replaced.

What have other Jaguar owners done with their inline 6 cylinder engines to flush out severely corroded coolant passages?

 

What have other Jaguar owners done with their inline 6 cylinder engines to flush out severely corroded coolant passages?

After you have run cleaning fluids (with soak time to take effect) You can get a radiator cap with a garden hose attachment from auto parts store: Remove pet ***** at left rear of engine and one in bottom of radiator. Install water cap on radiator and flush with good pressure to move particles out. Put pet ***** back and remove upper hose to radiator from thermostat housing and run water again. You do not have to run engine to flush, but you will have to to get cleaning agents circulated with engine running and warm.

While you have the radiator out, you will want to address water pump seal and bearings, they can not be in good shape after this amount of time. If you send it out for rebuild (or get an exchange), make sure they will replace corroded inlet/by-pass fittings.

I have an extra cover for the back of intake manifold from a later Jaguar, if you decide to take cross-over intake heating duct off, send your address to davmcelroy@cs.com and I will mail it to you.

Rgds David