Discussion
The vacuum pump on my 91 SE may be going out. The car makes a clacking noise especially towards the left front of the engine when cold. It seems to lessen as the car warms up but is still present. The timing belt was replaced only 6 months ago so I don't beleave it is the problem. Anyone know a good way to verify the vacuum pump's condition? And the best replacement proceedure? Thanks
Check the amount of vacuum. Also wouldn't hurt to grab hold of the pulley and see if there is any play. You can replace it with a $100 NAPA part with a few mods. There is a document on the Yahoo list in the files section under tech/engine:
<http://f6.grp.yahoofs.com/v1/IL2zQdXHSRZeyNQi3CHwakzUbrs0hQiahzOLhbnHukSIbfUjMSl_DCW7kUQhdA24l451KNkxX-bk4eJLMK27p11RebXCiGg/tech/engine/Vacuum%20Pump%20-%20NAPA-GM%20Lotus%20Cross%20Reference.doc>
written by Tim detailing the procedure. Not sure if that link will work. You have to be a list member to retreive it.
Dr.Hess
<http://f6.grp.yahoofs.com/v1/IL2zQdXHSRZeyNQi3CHwakzUbrs0hQiahzOLhbnHukSIbfUjMSl_DCW7kUQhdA24l451KNkxX-bk4eJLMK27p11RebXCiGg/tech/engine/Vacuum%20Pump%20-%20NAPA-GM%20Lotus%20Cross%20Reference.doc>
written by Tim detailing the procedure. Not sure if that link will work. You have to be a list member to retreive it.
Dr.Hess
The electric vacuum pump originated with power steering equipped cars. I believe Lotus felt it more cost effective to replace the mechanical pump with an electric one due to the space restrictions in the forward engine compartment rather than reconfiguring all the belts and pulleys. Plus GM was using these things in Cadillac's and big block motors etc. so it was readily available cheaply.
If you do the conversion and end up removing the defective mechanical pump you'd need a considerably shorter belt to drive the water pump off the crank. Shouldn't be that hard to size up a belt to go round the water pump, crank and tensioner.
From personal trials and tribulations with a Landcruiser and their $1600.00 vacuum pump it was imperative to keep the electric pump and check valve a good couple feet from the brake booster to avoid oscillation upon brake application.
Have Fun!
Steve
If you do the conversion and end up removing the defective mechanical pump you'd need a considerably shorter belt to drive the water pump off the crank. Shouldn't be that hard to size up a belt to go round the water pump, crank and tensioner.
From personal trials and tribulations with a Landcruiser and their $1600.00 vacuum pump it was imperative to keep the electric pump and check valve a good couple feet from the brake booster to avoid oscillation upon brake application.
Have Fun!
Steve
Hi,
One issue with replacing the belt-driven vac pump with the electric unit is that there will be no way to tension the waterpump belt. It's pulley is fixed, it is the vac pump (which is adjustable in it's bracket) that provides the tension on the belt. So a switch involves coming up with an alternative way to tension the belt. The mechanical vac pump lasts for many years and many miles, it is not really inferior to the electrical one, especially when the Esprit doesn't exactly have amps to spare anyway from it's alternator. Stick with the mechanical unit.
A trick to making removal/replacement insitu easier is to take an 8mm Allen wrench, and cut off about a 3/4" piece. This you insert into the cap bolt securing the vac pump to it's bracket. Then slip an 8mm 6 or 12 point closed-end wrench over the allen piece to remove it. There is insufficient clearance to use a standard allen socket or standard allen wrench.
Happy Motoring! ... Jim'85TE
One issue with replacing the belt-driven vac pump with the electric unit is that there will be no way to tension the waterpump belt. It's pulley is fixed, it is the vac pump (which is adjustable in it's bracket) that provides the tension on the belt. So a switch involves coming up with an alternative way to tension the belt. The mechanical vac pump lasts for many years and many miles, it is not really inferior to the electrical one, especially when the Esprit doesn't exactly have amps to spare anyway from it's alternator. Stick with the mechanical unit.
A trick to making removal/replacement insitu easier is to take an 8mm Allen wrench, and cut off about a 3/4" piece. This you insert into the cap bolt securing the vac pump to it's bracket. Then slip an 8mm 6 or 12 point closed-end wrench over the allen piece to remove it. There is insufficient clearance to use a standard allen socket or standard allen wrench.
Happy Motoring! ... Jim'85TE
Lotusguy said:
One issue with replacing the belt-driven vac pump with the electric unit is that there will be no way to tension the waterpump belt. It's pulley is fixed, it is the vac pump (which is adjustable in it's bracket) that provides the tension on the belt. So a switch involves coming up with an alternative way to tension the belt.
Easy. Just use the 907/ 912 Esprit water pump V-belt. Those engines used a direct-fit V-belt between the crank and water pump pulleys... no idler/ tensioner. Those engines didn't have vacuum pumps and all the non-PS versions used that arrangement. Any Lotus parts vendor can sell you the belt. Or order up the following:
HF (made in Germany) Continental SPZ677 Cw/9.5 x 690La
Lotusguy said:
A trick to making removal/replacement insitu easier is to take an 8mm Allen wrench, and cut off about a 3/4" piece. (Snip)...
Hmmm... your idea? I'll bet a Gear Wrench would work great with that.
Tim Engel
Lotus Owners Oftha North
>> Edited by Esprit2 on Thursday 14th April 07:12
>> Edited by Esprit2 on Thursday 14th April 07:14
Esprit2 said:
A trick to making removal/replacement insitu easier is to take an 8mm Allen wrench, and cut off about a 3/4" piece. (Snip)...
Hmmm... your idea? I'll bet a Gear Wrench would work great with that.
Tim Engel
Lotus Owners Oftha North
Don't even go there...
Happy Motoring!... Jim'85TE
teamlorenz said:
Is the napa unit a bolt on deal or does it need some customizing to work?
Chris,
Other than swapping the Lotus-specific parts onto it (pulleys, brackets, etc), it "can" be a bolt in. That document Dr. Hess referenced gets into that. I suggest you read it before proceeding. I can send it to you as a file attachment if you can access it elsewhere. Just let me know.
The NAPA pump's vacuum port points in a different direction such that the hose ends up closer to the exhaust manifold than with the Lotus OEM pump. Lots of folk have used it that way and don't report problems. For me, I just don't like having the rubber hose that close to the hot manifold. I suppose that could be handled by slipping a length of Fire-Sleeve over it, but I turned the spigot.
That's not easy since it's Loctited into the housing. Getting it out without breaking the nipple isn't easy. A propane or MAPP gas torch didn't get the joint hot enough without heat soaking the entire housing. But a friend had a tiny jeweler's acetylene torch that would put a very hot, pin-point flame right were it was needed. That killed the Loctite without over heating the rest of the housing. Then it's just a matter of cleaning off the Loctite residue and gluing it back in pointed down... as installed on the 910.
Regards,
Tim Engel
Lotus Owners Oftha North
Jim and Tim:
Thank you for the unexpected tip on using a chunk of 8mm hex rod and utilizing a box end wrench (ratcheting preferred).
When my car last had it's timing belt changed the tension clamp bolt unexpectedly disappeared from the vacuum pump and the whole mess was being held in place by the pivot bolt only. Not long thereafter the bracket broke due too vibration and things got warm quite quickly as you can imagine. Luckily things got shut down quickly and there is no apparent engine damage. Course no one wanted to contribute labour on this one. Hah.
I instead decided to repair this myself but noticed fairly quickly that a standard hex wrench was too long to clear the pulley and my fat sausage fingers couldn't get in there anyway. I ended up cutting the short side of the hex wrench so as to clear the pulley and then tigged on a chunk of rod so that I could steer the wrench into place. It was like fishing for prizes at the carnival. Many attempts and partial turns the bolt is now snug.
If only I had known of this sooner. I'd have saved myself Carpel Tunnel Syndrome. Please compile all of your most intimate Lotus shortcuts and insights into a dvd/cd version. Sort of like the 'Ask Smokey' articles published in P. Science years back. I am concerned that if you ever lose resolve or end up being diapered due to old age this valuable source of info will be lost forever.
Thanks again gentlemen.
Steve
Thank you for the unexpected tip on using a chunk of 8mm hex rod and utilizing a box end wrench (ratcheting preferred).
When my car last had it's timing belt changed the tension clamp bolt unexpectedly disappeared from the vacuum pump and the whole mess was being held in place by the pivot bolt only. Not long thereafter the bracket broke due too vibration and things got warm quite quickly as you can imagine. Luckily things got shut down quickly and there is no apparent engine damage. Course no one wanted to contribute labour on this one. Hah.
I instead decided to repair this myself but noticed fairly quickly that a standard hex wrench was too long to clear the pulley and my fat sausage fingers couldn't get in there anyway. I ended up cutting the short side of the hex wrench so as to clear the pulley and then tigged on a chunk of rod so that I could steer the wrench into place. It was like fishing for prizes at the carnival. Many attempts and partial turns the bolt is now snug.
If only I had known of this sooner. I'd have saved myself Carpel Tunnel Syndrome. Please compile all of your most intimate Lotus shortcuts and insights into a dvd/cd version. Sort of like the 'Ask Smokey' articles published in P. Science years back. I am concerned that if you ever lose resolve or end up being diapered due to old age this valuable source of info will be lost forever.
Thanks again gentlemen.
Steve
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