Lotus Elan Central

I have started the rebuild of my spare motor. I have been reading the posting about the Sh4rk and Dave’s Track Elan and it is about time I get mine going. A little background on the motor: This is the second time around I have had this motor in my hands. I originally bought the motor when I had my first Elan many years back but I never got around to doing much with it so I sold it with my old Elan some time back. Last year I finally got my butt in gear and bought another Elan and called the fellow who bought my old Elan and asked him if he still had the spare motor and if he was willing to get rid of it. Long story short, I now have this motor again and this time I am going to make it happen.

The motor is the 4XE1-T from an Isuzu Impulse RS Turbo that only had 1400 miles on it when it was hit hard in the rear of the car. (That is not a misprint, the motor only had 1400 miles) The motor is the same version as that use in the Elan but with a couple differences, the Isuzu motor has different cams and uses solid lifters instead of the hydraulic lifters used on the Elan motor. I have already bought the Lotus "correct" cams and lifters so this motor will be the same as that used in the Elan when I am finished putting her back together. I originally bought the motor from Frank at Sports Car World up near Waco, TX.

http://www.sportscarworld.com/

I have done a ton of research trying to find out in what way the two motors are different if at all. Each part removed from the motor will be take up to Sports Car World and compared and measured against an M100 motor that is disassembled already. I will post all my findings here for all to see.

Here is an Isuzu forum site with lots of information on the Isuzu version of our motor:

http://www.isuzone.org/forums/

Here is a great site with tons of informaiton on modifications that can be made to the 4XE1-T motor:

http://www.robietherobot.com/storm/geo_storm_mods.htm

One of the first things I did years ago was to purchase a new Lotus valve cover as pictured on the motor currently

Disassembly of the motor has begun. The intake plum and manifold have been removed. The Isuzu injector body is slightly different than the Lotus body. I have purchased a new Lotus injector housing and will take pictures comparing the two later.

I have already removed the cams and the cam gears from the head. I will picture those later.

The front of the motor with the water pump and all other pulleys removed.

The cam gears and camshafts have already been removed and I will picture later.

Look how clean this motor is

Intake side of block after removing the head and all other brakets and accessories including the oil filter adapter. The Isuzu version uses a remote oil filter and the adapter runs the line to the filter, the Elan version has the oil filter atached to the motor as we all know so well; therefor I had to buy the "correct" Elan oil filter adapter for making this motor the Elan version and I am tossing the Isuzu unit.

Anyone want to try changing their oil filter to a remote unit? Let me know if you want the remote adapter.

Here is the top and bottom of the block after the gasket has been cleaned off and the pistons and crankshaft have been removed. Notice that there are the two oil holes in the main journals that identify this motor as the turbo version (4XE1-T), so far, this motor is identical in every way to the Elan motor except for the lifters, camshafts, and the injector housing. (pictures of those different items to follow)

The old head gasket was carefully scrapped off of the motor while the block was turned upside down on the engine stand and then the block was vacuumed in order to make sure no fragments of the head gasket fell into the oil holes.

If you look carefully at the exhaust side of the block (on the top of the block) you can just make out the "B" next to each of the oil return holes. The "B" identifies the piston size that matches this block.

Not visible in the pictures bellow, but on the bottom of the block there is a marking that identifies the size of the crankshaft, mine is a #2 crankshaft.

Very thoroughly detailed picturing and description, really helps a lot all of us reading about it!

Keep up the good job and the detail picturing.

Costas

I have been sourcing out the parts that I want to replace and they include the main bearings and connecting rod bearings. Also, I want to get a complete gasket set for the motor but from what I have discovered so far, you have to buy each gasket separately since Lotus does not make a full rebuilt kit that you can buy off the shelf. If anyone knows different please let me know.

I have found a full rebuild kit from a local Isuzu dealer for $175.00 (special order) and I am going to price out the main and connecting rod bearings with them since my price from Dave Bean on the mains was outrageous. $49.00 for EACH main bearing (you will need five)

Today I got the head disassembled. I removed all the studs from the head and then carefully cleaned off any remaining gasket residue, this weekend I will soak the head and start cleaning it up (not that it needs much).

The head is pictured with the Isuzu solid lifters (tappets) and the Isuzu camshafts. Notice each tappet is labeled so that is can go back into the exact bore that they came from. I have bought new Lotus hydraulic tappets but I am thinking that it would be better to go with the solid lifters so there is less valve float and the motor can then rev higher.

I have checked the camshaft pulleys with the Lotus pulleys and they are identical with exact same placement on the timing marks.

One of my objectives with this project is to point out the differences between the Isuzu and Lotus version of the same motor and then buy all the "correct" Elan components to make this engine a true Elan motor.

The lower intake manifold (injector housing) is different on the Isuzu version of the motor. Compared to the Lotus lower intake manifold the Isuzu version does not have idle air control valve. The Lotus version also has an idle air hose that comes from the throttle body. I did not see any other place on the Isuzu motor where this sensor could go there for I can only assume that the idle air control valve is only used with the Elan version of this motor, hmm. Let me know if this is not the case.

I have purchased a used Lotus version of the lower intake manifold to make this motor into the Elan version (pictured bellow with the Isuzu manifold) The manifolds have been disassembled, the butterfly valves have been removed and the Lotus version will be sent off to Extrude Hone to be polished.

As the motor is disassembled, every part is labeled and bagged with the exact bolts and nuts associated with the part. Next week each part will be cleaned to look like new, some parts will be taken to the machine shop to be dipped and soaked in hot solvents, other parts can be clean with store bought cleaners in the garage, I prefer to use lacquer thinner as my cleaner of choice. The block and the head will be soaked in order to make sure all traces of any old oil or foreign particles are removed from the oil ways.

The block and the head will also be check to make sure they are "true"

IMPORTANT NOTICE!

- If there is anything within the motor as it is disassembled that you want me to take a picture of OR if there is any part of the motor you want see up close , please make sure you let me know and I will post it

The head, the lower intake (injector housing), the exhaust manifold, and the intake plume will all be shipped off next week to Extrude Hone to be ported and polished.

http://www.extrudehone.com/oem.html

Whilst you're sending stuff out...'Turbocharger mentioned recently that 'racers' have the turbo housings extrude honed?

You bet, first I need to figure out what turbo I am going to use. Most likely the same one Dave is using, but yes, that should be sent off as well but it might be in a separate mailing

Whilst you're sending stuff out...'Turbocharger mentioned recently that 'racers' have the turbo housings extrude honed?

If you do the extrudehone you only need to do it on the turbine housing. How much HP do you want to make? May I suggest our website as a guide which may be helpfull no matter what brand Turbo you decide on. Also contact me if you have decided on a particular Turbo and I may be able to get you a much better price.

http://www.turbobygarrett.com

,Russ

Thanks Russ, I will send you a PM. I want to get around 275 hp

LotusM100 wrote:You bet, first I need to figure out what turbo I am going to use. Most likely the same one Dave is using, but yes, that should be sent off as well but it might be in a separate mailing

And what one will that be? j/k...the plan right now is to stick with the T3 for the first full tune. A GT28RS (Disco Potato) similar to what Russ is playing with will most likely make an appearance sometime next year, but my initial guess is there will be more turbo lag than I want, so I'll end up sticking with the T3. But I'd love to be proven wrong! More HP potential in the DP...

Excellent pics, Al! I won't even bother getting the standard build pictures posted from what my shop took. Yours will be a perfect reference for folks. Anxious to hear the next update!

looking good, Al. Nice pics and write-up so far!

As noted, I have two objectives with this thread, one is to build a hopped-up motor and the other is to point out any differences between the same motor used in the Lotus Elan and the Isuzu Impulse. I have ordered two complete sets of gaskets, one set is a full set of Isuzu gaskets and the other set is a full set of Lotus gaskets. I am sure that all Lotus does is repackage the Isuzu gaskets but in order to be scientific I will get both sets and compare, I will use the second set for the original Lotus motor that I am taking out of the car.

Here is a little problem that we might start running into, the complete engine gasket set is no longer available from Isuzu and the head set is getting limited! The fellow I am working with at the Isuzu dealership has been more than helpful and we have had to piece together a complete set of gaskets, the head gasket set that is still available from Isuzu but the bottom end is not. I bought the complete head set and then piece together the rest of the gaskets and seals but we can not get the rear crank seal from Isuzu any longer.

The Lotus set only comes as a complete head set and then you have to piece together the missing gaskets as well. The Isuzu head set cost $135.00 US and the Lotus head set cost $97.00 US WOW! I was not expecting the Lotus set to cost less. I will take pictures of the two sets when the come in and post pictures in this posting (I will edit this posting with the pics)

NOTE: When ordering parts through a Isuzu dealer make sure you tell them you have the same motor as an 1991 Isuzu Impulse RS turbo

[ picture of gasket sets will go here ]

This maybe a possible error in the Lotus service manual or a difference between the Elan motor and the Impulse motor. I have discovered that my connecting rods bearings do not have an oil hole in the bearing nor the connecting rod as illistrated in the manual. I have checked with Dave Bean and they have also informed me that the rods and the bearings they have DO NOT have the oil hole as suggested in the manual. I am attaching an image of my connecting rod and the bearing and I also have a picture from the manual.

If anyone knows more about this please let me know.






From the service manual showing an oil hole in the bearing and through the connecting rod