Lotus Elan and Lotus Elan Plus 2 Forums

I'm starting to get serious about a new engine for my S2 SE DHC street car that hasn't been on the road in over 20-years.

I've got a lot of good stuff for this build including a new 26R chassis, all aluminum T9 with Voight's conversion, 3.54:1 rear end with a Quaife ATB in all aluminum housings, Dave Bean Engineering (DBE) CV joint conversion and uprated rear axles, TTR suspension and roll cage, and other good stuff.

I really want an aluminum block based engine for weight savings and oil control.

I've been surveying what's available and the best option so far are:

1. A new aluminum engine block from Steve Jennings with LTC height and 90 mm nikasil bores is $4500. This block is cast for dry sump oiling in that there is no provision for a wet sump pump feed and drain tube. Steve is recommending a steel bottom end giving a displacement of 2.2L. I believe this is what Jim Hall installed in Jay Leno's S2. Jim told me he really doesn't know all the specs on Jay's engine as it was sourced compete with head from Steve Jennings. Steve is also recommending a new head be sourced from DBE who quotes $4250 for a bare head (caps are align bored) and $3500 for head fixings including cams, valve seats, guides, springs, retainers, studs, etc.) Some simple math tells me this likely to be a $20k engine and will probably be good for 180-200 bhp in street trim on DCOE45's. Besides the price, I'm not enthusiastic about the necessary dry sump system. Some folks with dry sump systems mount their oil tanks in the passenger foot well, which in a RHD car is on the left hand side of the engine, whereas the dry sump pump is on the right hand side of the engine. In addition to the plumbing being a nightmare, I'm not keen about a hot oil tank along side the passenger's feet. A possible solution is to use a wet sump pan as the oil tank, and take oil out of the side of the pan before going to a single stage of a dry sump pump. The output from the dry sump pump would go to a thermostatically controlled oil bypass valve where it would either go through an oil cooler or bypass the cooler and return to an oil filter and then the main oil gallery on the left side of the block. They call this type of system a California dry sump. Anybody ever do a system like this? A refinement would be to incorporate baffles in the sump and or a DBE swinging oil pickup. Jim Hall much prefers a wet sump system for the street. The down side to a large displacement engine is that the whole exhaust system needs to be replaced if one wants to harvest all the goodness. What happens if something goes wrong and the bore needs to be renewed? I know the nikasil can be stripped and replated for about $1000 but what if there is damage to the base aluminum? Is there enough meat to install sleeves?

2. The second option would be a useable BDP block that is currently sleeved at 82 mm, but the owner recommends the sleeves be replaced. This (tall-crossflow height) block is available for $2500 and a new Kidde, 77.62 mm, wide journal steel crank is available for $1000. I would likely have the block machined to take something like 85 mm bore sleeves, giving a displacement of 1762 cc's. The BDP block will accept a wet sump pump but probably not the internal cross block oil drilling. Still, the oil system would be pretty much the same as the California dry sump but without the external sump to pump line. The down side of this option is I think there will be about a 1/4 inch interference between the bonnet cover and the forward edge of the cam cover. How have other tall block users dealt with this clearance issue? I would likely pair this option up with a new DBE head.

Options, guidance, warnings, mental health information requested.

Bill

What a project ! But may I ask what is the final use of this car ? Street or Racing ?

Hi Bill
You seem set on an Alloy block for lighter weight but it is a big expense and creates a lot of other complexity such as the oil system for a saving of maybe 20 kg. There are probably easier and cheaper ways to save that much weight .

With a road useable cam you will top out around 180 hp with a top quality head pretty much regardless of the capacity as you will hit the head / cam breathing limit before you get near the rev limit on a steel bottom end -- you will just need to rev the smaller engines a little harder to achieve it. However the bigger engines will give you more torque low down and a 2.2 litre would be a lot of fun in the traffic light drags.

An really interesting exercise to build what your looking at though.

cheers
Rohan

Wow is all I can say....what a motor. The specs look fantastic......I don't know if you are going to build the motor or hire it out. I have been exploring engine rebuild options for my S4 project and am going to send the motor to Ted Wenz at Savannah Race Engines to be rebuilt and beefed up. Ted does a wonderful job on my race engine, and I will have a spare race engine down to him in the next few weeks. ted is a great resource...you may want to bounce some ideas off of him.

Hi guys.
I spent the week trying to gather some information. Lots of emails sent out for parts pricing and availability.

Gherlt,
This will hopefully be a fast street car.

Rohan,
Yep, the alloy block is a big expense to save 40 lbs and the oil system is a big issue. John McCoy may be able to help with one of his Johnson?s wet sump pumps and modified sumps. I need to chat with him.
I agree there are cheaper, but not necessarily easier ways to lose some weight . Still, it?s consistent with the rest of the drive train. I?m all aluminum throughout. The other benefit of all aluminum castings is there is no coefficient of thermal expansion (CTE) mismatch, so hopefully, oil leads should be less likely.
180 bhp is 26R territory and a good neighborhood to be in for the street IMHO. Anymore and I think it can start to get scary and a lot of the downstream running gear will likely absorb a lot of abuse. I?m thinking a 77.62 mm stroke, 86 mm bore for 1804 cc?s, 5.23 inch Carrillo rods, and 10.2:1 CR on DCOE 45?s, if I go with the BDP block. I?ll likely go for the new DBE heads with the small competition valves, 1.625 inch intakes and 1.375 inch exhausts and suitable spring packs. John Stowe says the head ports only need a cleaning with a flapper wheel and they are pretty much good to go. Cam is TBD. I need to strike a compromise here perhaps limiting lift and lift rate for better durability. The thing is with a smaller bore, there is ample material for the head gasket to seal in all respects and the shorter stroke should mean a little smoother engine. Together, there should be a little less wear and tear on the drive train then with the torque of a 2.2 liter engine and the opportunity to go bigger later if desired.
The steel bottom end is probably overkill but should make the bottom end pretty much bullet proof. The 77.6 mm Kiddie crank is really going to cost me $2k, not $1k like I originally thought, if I buy it with the BDP block. The crank is supposed to be a wide journal crank but I can?t find any specs on line that will confirm Kiddie ever made one. I believe Doug Kidde sold his business to Arrow Precision. Arrow Precision lists a number of cranks, but none are specifically described as 77.62 mm, wide journal cranks. All the 77.62 mm crossflow/LTC and FV cranks show a pin width of 23.95 mm, where the LTC standard stroke crank shows a pin width of 27.3 mm and I believe corresponds to a wide pin.
So what?s the deal with wide pin versus narrow pin? It is my understanding that a wide pin might be better for a street engine where one could accept a little less than the optimum competition performance. In essence there is a little more bearing area at the expense of a little more hydrodynamic drag. I think this is a horsepower versus bearing loading tradeoff.
The other big issue is what to do about the exhaust system. I?m thinking it?ll have to be big bore throughout, whatever that means? DBE recommends a TTR exhaust manifold, but I don?t know which one. Personally, I think I prefer a stainless steel one with gas analyzer tube features on each branch of the primaries and an O2 bung on or after the collector for AFR measurements.

Uglyduck,
Quite frankly I?m not sure who is going to build this engine. A lot depends on which way I go. If I buy a new block from Steve Jennings, It may make sense for him to do some or all of the assembly and perhaps dyno it and ship it as a ready to install unit.
If I go with the BDP block, I?ll likely do the assembly after I have the sleeves either bored or replaced and honed. It turns out my local automotive machine shop, Precision Automotive in Simsbury, CT had last done my head 25 years ago and had about a half dozen receipts in hand from doing sleeve replacements on other BD blocks. The customer for the sleeve replacements was Peter Marcovicci of Marcovicci-Wenz Engineering in Ronkonkoma, NY. Peter Marcovicci and Ted Wenz were partners and co developers of John Stowe?s replacement head for DBE. What a small world. When I called Peter, he said Precision Automotive did a good job on sleeve replacements for his customer?s BD blocks. I should probably close the circle and have a chat with Ted Wenz. I wonder if we could get some dyno sheets out of Ted for the new head development tests.
Bill

Bill,

You might consider losing even more weight with these magnesium items on offer here?

lotus-parts-f33/magnesium-bellhousing-and-gearbox-casing-t30778.html

I'm envious of your build

Cheers

Rob

Bill
I have a S1 rhd with dry sump in Danbury. Come see it if you like.
The plumbing is easier than you think.

Eric

Hi Rob.

Good thought in that magnesium is lighter than aluminum for similar strength, so I could save some additional weight. But, I believe magnesium corrodes more easily than aluminum. Magnesium makes sense for a racing application, but I don't believe it would be a good choice for my road car. The other thing is that I have a T9 five speed that is already all aluminum. Also, with all aluminum castings there is no CTE mismatch, so oil leaks should be minimized.

Hi Eric.

I'd love to see your S1 and it's dry sump plumbing. Please PM me when we could meet. I'm retired so my schedule is pretty open.

Bill

I have always believed that the narrow journal rod and drank design came out of the need for narrower journals for the DFV development that was then fed back into the BDA. No hard evidence but my presumption

cheers
Rohan

Hi Doug Kiddie did sell his business to Arrow. Before buying two cranks from DKE, I visited so see them and check out the work v's other options available.

Their standard LTC crank at the time was narrow journal, but they did manufacture cranks to special order, these cranks were designed to operate safely at very high RPM, we discussed rods and they recommend for high RPM the use of narrow journals to reduce drag and heat build up, but noted the lower time between replacement f bearings, as the downside of less bearing surface area is that the loads are taken by a smaller area and thus wear. They are intended for race engines which get regularly refreshed. I've been offered a number of narrow journal steel cranks out of street/historic rally cars that had undersized big ends, most likely due to to long between rebuilds.

One is in an engine going back together at the moment, the other is still in its box.

V

Thanks V.

I asked Tony Ingram in an email, "Can you tell me what the tradeoff is between a narrow and wide journal bottom end?"

Tony replied,"The narrow journal bearings allow for a lighter assy.. less material in the crank, rods are lighter, and less friction in the bearing. Great if your building a full race motor but I do not think you would feel it under your foot in a street application."

It looks like a wide journal crank and rods are the way to go for my street engine.

I also asked Tony, "Can a 6-bolt flywheel be safely used on a 12-bolt crank?"

Again, Tony replied,"Yes a 6 bolt flywheel will work on a 12 bolt crank... I machine down the head of a socket head cap screw and use it as a dowel."

It turns out the Fidanza flywheel I have on the shelf is for a 12-bolt crank.

Bill

Hi Bill
I'm back if you still would like to come see the car.

Eric

ecamiel wrote:Bill
I have a S1 rhd with dry sump in Danbury. Come see it if you like.
The plumbing is easier than you think.

Eric

rgh0 wrote:I have always believed that the narrow journal rod and drank design came out of the need for narrower journals for the DFV development that was then fed back into the BDA. No hard evidence but my presumption

cheers
Rohan

Rohan,
Isn't the narrow journal also needed to create room for counterweights on both sides of the connecting rod? I would not be surprised if there was also some feedback from the DFV development.

Hi Russ
It probably made it easier to design a 8 counterweight crank but it is not an absolute requirement. You can get 8 counterweight wide journal cranks. The Datsun L18 crank that you can modifiy and use in place of a 1600 crank is a 8 counterweight design in one of its versions.

cheers
Rohan

bill308 wrote:I'm not enthusiastic about the necessary dry sump system.

Bill,
What about the oiling system that John McCoy at Omnitech was developing a couple of years ago? It is akin to the "California dry sump" that you mention. I don't know if John ever got his system in production but he did have and external suction line from the side of a normal wet sump to the oil pump inlet. Therefore this could be used in one of the light alloy blocks intended for dry sumping. You would also need to route the high pressure discharge from the pump to the main gallery on the exhaust side of the engine because the light alloy block also are missing the cross-block oil feed drilling.

http://omnitech-engineering.com