84 Esprit Turbo Engine Mods

[hotrod1000]

I am currently in the process of stripping down the engine after breaking two valves and number one piston. After only covering 2500m since the last rebuild I am interested in any modifications that could improve the reliability, performance or maintenance of the engine when complete. All suggestions considered.
Steve

[DrieStone]

I'm sure Jim will post his usual list of modifications he has done. A few other owners have tried to glean as much as possible from his (and other's) postings as well as other information and posted it at http://esprit.driestone.com/index.php/Esprit/PerformanceCookbook . Copied from there:

Turbo Esprit Wiki said:

The stock short block is pretty strong and you shouldn't need to "upgrade" beyond many the OEM parts. Ceramic coated JE pistons is a worthwhile investment (especially if you need to do a rebuild anyway.) This will increase your compression ratio to 8.5:1. JE pistons are not off the shelf for this application so you will have to have them custom made. You can work with the folks at JAE to get the right pistons. Piston cost is about $750 plus another $150 for the ceramic coating (for the set of four.) You could replace the cast piston liners with the newer HC liners, but the cost of the new liners is about $1000. The alternative is to hone the cast liners and coat the skirts with a wettable dry lubricant (molybednum disulphide) to increase oil carrying capacity. Although the HC liners are certainly good insurance, the "upgrade" if fairly cost prohibitive. Lastly, you should balance and lighten many internal components as possible. The crankshaft and the connecting rods are very robust and are many times larger/stronger than needed. A good machinist should be able to dramatically reduce the weight of these items.

On that page you will also find tips and suggestions for other parts of the Esprit (including head work that you may wish to do while the engine is out.)

I myself will probably be following many of these suggestions in the next 12 months as I have a head gasket leak (I think) and want to get a little more oomph from the car in the future.

P.S. Most of the info collected on the site has been done by those of us in North America (so there are a few items that won't apply to cars in the UK.)

>> Edited by DrieStone on Monday 26th July 12:06

[G_Reaper]

I am rebiulding an 83 Turbo engine.
I have spoken at great length to a number of specialists and it really comes down to budget.

I have replaced the block with an HC Excell block and new Esprit SE turbo pistons and liners. I thought about going all the way and building it up with a HC head but that would bring in other problems such as needing a different water pump carbs inlet manifold inlet casting from turbo to inlet plenim etc.

In the end I have kept the engine LC replaced the pulley wheels with HC pulleys as this means the engine can run on the later improved cam belt with double the service intervals. Later manual cam belt tensioner (More reliable and simpler than semi automatic). These mods should make it a little bit more reliable and durable without increasing power and spending a fortune.

How did your engine come to grief so soon after a rebuild?

Regards Mike

[hotrod1000]

Just read through most of the posts and your information repository. Probably overloaded with info now, need a couple of days to consider the options. Thanks for the advice.

Ive got the head off the engine expecting the cause to be a carb running lean but if anything they were a little rich, it also stumbled off the line and on hard cornering. Theres no obvious cause so it looks like a valve just broke, took another one out then went through the piston.

Steve

[f1karting]

If you have a large budget.. (which you may need anyways if undertake a serious rebuild/upgrade project).. you can still buy new crate motors (SE engines I believe)from guys like Dave Bean, (and no doubt others as well). I believe they are about $8-10K. That would be my choice if I had to do a major overhaul.. Jan

[DrieStone]

I just noticed that there is a HCI engine on eBay, fully rebuilt. I think starting bid is $3500. You'd probably have to spend another couple grand to set up the electronics.

[G_Reaper]

Hi Steve,

Did you use your old valves in your rebuild the first time around?

I was informed that as part of the valve stem is hollow they are very prone to becoming brittle and snapping off when re used if they have had the smallest tap by a piston or even on the bench after removal. This particularly applies if they are of some age.

Cheers mike

[lotusguy]

G_Reaper said:

Hi Steve, Did you use your old valves in your rebuild the first time around? I was informed that as part of the valve stem is hollow they are very prone to becoming brittle and snapping off when re used if they have had the smallest tap by a piston or even on the bench after removal. This particularly applies if they are of some age. Cheers mike

Mike,

Not sure where you got your information, but the valve stems are definitely solid, not hollow as you suggest.

The intake valves have solid steel stems while the exhaust valves have Sodium filled stems to better carry away heat (the intake valves operate cooler due to the cooling effect of the charge passing over them). Remember, the valves can only transfer their heat through very brief contact with the valve seat during each cycle.

While contacting a piston will bend the valves, they aren't typically known to actually break although I would agree that you cannot really straighten a valve stem once it's been bent. Happy Motoring! ...Jim'85TE

>> Edited by lotusguy on Wednesday 28th July 14:50