Lotus Elan

Request for feedback on a new engine

PostPost by: bill308 » Fri Mar 28, 2014 10:46 pm

Hi Eric.

Welcome back. It looks like lousy weather through the weekend. Does a meeting on Saturday, April the 5th work for you, say about noon?

Hi Russ,

I think I did send John McCoy an email enquiring about his oil pump. No answer yet so I guess I'll try again. From what I can see it can accept a hose out the side of the pan. Supposedly it works at a lower pressure so power losses are lower. I couldn't find a kit or pump source listed anywhere. There is also supposed to be a gated pan that John developed to go with it.

I did contact Dave Bean early in the week and asked him about his swinging pickup. Dave said it generally worked well but was still prone to suck air if the car went air borne. I suspect this would be a problem with any wet sump. The other thing is the pickup bearings were sourced from a surplus store years ago and may or may not still be available. Dave says if the rotation feels ok then the bearings are probably ok.

I decided to go with the used BDP block and NOS Kiddie wide journal, 77.62 mm stroke crank. The BDP block was generally used for midget racing in the USA and was run on alcohol. This block is machined to accept a wet sump pump, although a dry sump pump can be fitted. The deck height is reported to be between that of a LTC and cross flow block. In any event, there is no cross block drilling for an oil passage, so a hose to the oil gallery on the exhaust side of the block will be required. If I go wet sump, I'll incorporated a thermostatically controlled oil pump sandwich plate with a bypass and an oil cooler feeding the exhaust side oil gallery. I'll order up a tall timing case front and back plate for a cartridge water pump and avoid the spacer piece.

Supposedly, the BDP block is sleeved for about an 82 mm bore. Peter Marcovicci told me these blocks were generally bored to 93 mm to accept a 90 mm ID sleeve. I'm really hoping I can just bore the existing sleeve to about 87 mm for 1846 cc displacement. In any event, if new sleeves are required they are about $600 a set and $600 to install. These would be floating sleeves, registered and retained by top flanges. The block is heated, the old sleeves are tapped out, the new sleeves are chilled and then dropped into the block. Once installed, the sleeves are bored and honed to final size. The machine shop is telling me that because they are floating sleeves, a torque plate is not required to bore and hone the new sleeves. I'll go with forged pistons and wide journal, Carrillo 5.23 inch center-to-center rods with ARP big end bolts. This should give me a bottom end good to at least 8500 rpm of which I probably only use 7500 rpm.

Bill
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PostPost by: CBUEB1771 » Mon Mar 31, 2014 11:26 am

bill308 wrote:I think I did send John McCoy an email enquiring about his oil pump. No answer yet so I guess I'll try again.


Bill,
I find it is often better to call John at Omnitech rather than wait for an email. He sent me a note announcing the oil pump kit a few years ago. I think the plan was for a complete kit, save for the sump, I recall that you need to modify your own
Russ
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PostPost by: bill308 » Wed Apr 02, 2014 10:29 pm

Hi Russ,

I'll have to give John a call.

Hi Eric,

Thanks for meeting me yesterday. I had a terrific time. Your S1.5 is very impressive. I really have to take a hard look at what tires I plan to fit to my S2.

Placement of the dry sump oil tank in the passenger foot well seems acceptable, unless you are much taller than my 5 ft. 9 inches. It may also get hot there during a hot summer day, but on an early April day this was not a problem.

There is no question in my mind that a dry sump system is the best. The question to be answered now, is a wet sump system adequate for normal road and occasional track use?

A dry sump system on a RHD Elan is ugly with oil lines running from one side of the engine bay to the other. But it guarantees oil to the engine under all circumstances. Every other scheme is second rate. Even DBE's swinging pickup will suck air when airborne. Does a dry sump system supply air when airborne, probably not, as there is an accumulation tank. As long as the scavenge section flows more oil than the pressure section, there will be no air bubbles.

My local track, Lime Rock Park, has an up hill right hander where one can become airborne under full throttle. Dave Bean told me he has seen bubbles of air pass through the oiling system of his 26R, when he was running a non dry sump system and became airborne.

When I last ran a time trial at Lime Rock Park, I did not notice any indication of oil starvation by looking at the oil pressure gage. There are two points where oil starvation would be an issue, at the conclusion of big bend (180-degree turn - double apex) and the up hill right hander, at the end of the back straight, where one would likely go air borne for a short period of time.

I think the swinging pickup wet sump system would work acceptably for the 180 degree, double apex big bend, but might have a problem at the crest of the up hill, right hander at the end of the back straight. How long without oil pressure is it acceptable, under full throttle?

Eric showed me several differential output shafts exhibiting plastic deformation in the spline area. I spoke with Dave Bean on this issue and he suggests my CV joint system should upgraded with new high strength output shafts, for about $500.

Bill

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PostPost by: rgh0 » Thu Apr 03, 2014 1:31 am

Hi Bill

Agree if building a big engine Elan and planning to use all the power you need stronger diff output shafts than the standard early version that twists. If your going to seriously use the car on the track then also high strength rear hub shafts and if you have bolt on wheels then the smaller diameter front stub axles should be replaced with high strength ones of these also. The standard engine mounts also have a relatively short life. A browse of the TTR catalogue to see what he sells as stronger bits for competition cars is a worthwhile if wallet stressing exercise!!

Even a second or two with the indicated oil pressure dropping below normal due to loss of suction can result in catastrophic engine bearing failure if it occurs for a few laps and at a point of high revs and full throttle which is normally the case as it is typically when you are accelerating hard out of a tight corner. (Been there done that!)

A properly set up baffled wet sump system will work for a twin cam in any track situation I have come across both in my Elan and in friends very hard driven S4 Seven and Twin Cam Europa. It should handle any of the situations you describe especially if you don't see any indicated pressure loss currently but a dry sump system is the ultimate solution if cost and racing regulations allow it.

cheers
Rohan
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PostPost by: CBUEB1771 » Thu Apr 03, 2014 1:38 pm

rgh0 wrote:The standard engine mounts also have a relatively short life. A browse of the TTR catalogue to see what he sells as stronger bits for competition cars is a worthwhile if wallet stressing exercise!!


Has anyone tried the heavy duty engine mounts from Kelvedon?
http://www.kelsport.net/parts/product_d ... ectionID=6
It is a nice design but I wonder if there is not enough compliance for a road Elan.
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PostPost by: rgh0 » Thu Apr 03, 2014 1:48 pm

I use the similar mounts from TTR in my competition Elan and yes you would find the shaking / vibration at idle especially to be annoying in a road car I think. With a standard road engine and standard flywheel the shaking at idle will be less and maybe they would be more acceptable but then you don't really need them for a standard engine either

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PostPost by: bill308 » Sat Apr 05, 2014 3:20 am

Hi Rohan.

Are you saying the Elantrickbits baffled sump design is relatively immune to going air borne and will reliably provide oil without an air bubble?

My Elan started life as an SE so it has the KO's and better front stub axles. I replaced the outboard rear axles with high strength DBE units at the same time I installed the CV joint system some 20+ years ago.

Eric took me for a ride in his very impressive S1.5 earlier this week. Thank you Eric. Later he showed me several damaged differential output shafts. One had sheared at the end of the spline and several others showed a twist in the spline at this same location. Eric's car is very potent yet streetable.

I have the TTR motor mounts, torque rods and bushings, fustacones, and lotocones. If I find any of the pieces are too stiff, I'll make the necessary adjustments. Going in, I'll be a little on the stiff side everywhere.
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PostPost by: rgh0 » Sat Apr 05, 2014 11:30 am

when the car goes airborne the oil goes up with it. When the car starts to come down the oil comes down under gravity in the same way, plus you cant be at full throttle with the wheels in the air so load on bearings will be reduced. The baffles and top windage tray keep enough of the oil around the pickup to not see any pressure loss on every track I have been on, though I don't have any tracks where I get fully airborne but the car does get light going over the top of the hill at Phillip island.

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PostPost by: bill308 » Sun Mar 29, 2015 10:24 pm

It's been almost a year since I last added to this thread.

The BDP tall block initially supplied came from Japan with an unknown history, but was sleeved with very small diameter liners. Marcovicci-Wenz Engineering, the engine builder for my engine, removed the sleeves and pressure tested the block. It proved to be porous and not worth the risk to me to see If it could be saved with a Loctite impregnation process. After months of negotiation, the block supplier offered me a new Steve Jennings aluminum block, of LTC height, with sleeved 89 mm bores, but at increased cost. This block requires an external oil line to the oil gallery, so I will dry sump it. The oil pan will be a Titan with 3/4 inch scavenge line and the oil pump will be a Titan 5-port with a 1+ inch scavenge lobe and a 0.7 inch pressure lobe and -12 fittings. This special pump was specified because the block is aluminum and expands/contracts more due to heat than cast iron, potentially leading to increased bearing clearances. The extra volume is to be conservative from a flow standpoint. Because of the shorter deck height, I swapped the new 5.23 inch Carrillo rods for my engine suppliers 4.83 inch rods. 5.23 inch rods leave little room for error on an LTC height aluminum block. The resulting piston height are a little iffy and unless the block remains undecked, the rods and pistons might have to be replaced at a future time. LTC standard rod length is 4.8 inches, according to the Work Shop Manual. 4.93 inch rods, also available from Carrillo, would likely be the best choice for my LTC height block, but the 4.83's were a no cost swap from my block supplier. The tall block timing chest I had would need to be cut down to fit, so my block supplier provided a new LTC height timing chest and cartridge water pump. The other coup was scoring one of John Stowe's early production heads, cast and machined in CT, USA, by John. My engine builder helped develop these heads and says they only need about and hour's worth of porting. We'll be using the DBE (D-production) 1.625 inch intakes and 1.375 inch exhaust valves of racing length. Rohan, I think it's time for the next installment of you cam gear postings. :D

My engine builder will provide new custom pistons and I'm still thinking a CR of about 10.3:1 to be able to run on readily available 91-93 octane pump gas with 10% max ethanol. What do you guys think?

I want to use a pair of Weber (45DCOE45's) 152g's for carburation. The extra (4) progression holes are a concession for street tuning and drivability. I'll be using TTR exhaust and intake systems. The exhaust system will have an oxygen sensor bung welded in for tuning purposes. The complete engine, including induction and exhaust systems, will be tested and tuned on an engine dynamometer.

I plan to use an Electromotive, crank fired ignition system. This system is fully programmable and reliable, but pricey and requires the fitment of a trigger wheel to the crank pulley and a pickup to the front timing case. It can be programmed to utilize a manifold air pressure (MAP) signal and knock detector if desired, so plenty

Cam specification is unknown at this time. My engine maker recommended we go to his cam grinder and get the cam grinder's recommendation. I'm thinking a very high lift street cam for excellent low end torque and good gas mileage and drivability.

Bill
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PostPost by: rgh0 » Mon Mar 30, 2015 10:06 am

HI Bill

On compression ratio it depends on the cam you choose but you can certainly go higher 10.5:1 to 11.0:1 is doable and needed with the sort of cam you should be using for you intended enthusiastic road use with a big capacity engine. With electronic timing and ability to retard in knock situations you should be able to comfortably do 11.0:1

You need a duration around 280 to 290 degrees seat to seat and lift in the .42 to .45 inch range. Most of the cam suppliers do these sort of cam these days. John McCoys cams are my favorites these days as he seems to get the highest lift into the shortest durations which is what the twink loves but also worthwhile talking to Tony Ingram about his options. The others like Dave Bean, QED, Elgin and others all do comparable cams.

Ideally you want cast iron cams with the long bolt modification running on lightweight steel buckets and a suitable valve length and spring pack for the cams base circle selected. Sourcing new cast iron blanks has apparently been hard recently and some of the suppliers have only been offering steel cams. Tony Ingram is my preferred supplier of springs packs and buckets currently as his offerings generally fit the rest of my valve train preferences best. You can build it many different ways and it will work but some ways are better than others IMHO. Happy to talk more about the details, I dont think I will get time to continue my general high lift cam modification write up in the next few months as I started a new job today which will be full on for a while.

cheers
Rohan
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PostPost by: cabc26b » Fri Apr 03, 2015 2:47 pm

Bill ,

I would take a hard look at the Johnson oil pump running in a stock oil pan with baffles. I have been running one for some time now ( like 4 years) with out issues . You should also make sure your builder works the rest of the oil system - mine has a set of specific things he likes to do to manage the flow of oil in the engine ( modifying jackshaft etc etc) .

Regards,

George
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PostPost by: bill308 » Mon Apr 06, 2015 10:30 pm

Hi Rohan.

Thanks for you thoughtful feedback.

My engine builder, Marcovicci-Wenz Engineering, like the steel cams so the long bolt putting the snout in compression is not needed. We'll see what the cam grinder recommends. I beginning to warm to the idea of CR's greater than 10.3:1. In the US, octane rating is measured by (RON+MON)/2. The highest, widely available pump gas is 93 octane, which includes up to 10% ethanol. I'm not sure what CR this will support, assuming an 89 mm bore and hemi head.

Hi George.

Where did you purchase the Johnson oil pump?

My engine builder is concerned with engine clearances. Aluminum expands and contracts more with heat changes than cast iron. This means at high temperature, bearing clearances could be larger, requiring more flow to maintain pressure.

I purchased a Titan oil pan, full trough, 3/4-inch scavenge port, from Wilcox Engines. I purchased a special Titan 5-port pump from DBE, which has 0.7-inch pressure lobe and 1.0+inch scavenge lobe and 3/4-inch scavenge tube. The next issue is where to mount the dry sump tank? TTR recommends a boot mounting, yet others recommend a passenger foot well mounting. The boot mount requires longer lines, but likely improves weight distribution, but a foot well location minimizes line length and pressures losses at the potential expense of reduced passenger leg room and probably more cockpit heat. I will likely run an oil cooler with a thermostatically controlled bypass circuit. This should enable the engine to come up to temperature reasonably quick and provide additional cooling when needed.

Bill
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PostPost by: rgh0 » Tue Apr 07, 2015 9:59 am

bill308 wrote:Hi Rohan.

Thanks for you thoughtful feedback.

My engine builder, Marcovicci-Wenz Engineering, like the steel cams so the long bolt putting the snout in compression is not needed. We'll see what the cam grinder recommends. I beginning to warm to the idea of CR's greater than 10.3:1. In the US, octane rating is measured by (RON+MON)/2. The highest, widely available pump gas is 93 octane, which includes up to 10% ethanol. I'm not sure what CR this will support, assuming an 89 mm bore and hemi head.

Bill



HI Bill
Wenz certainly should know what they are doing. If running steel cams on steel buckets you ideally need about a 10 Rc hardness different between the two to avoid galling. The buckets (and cams) should have a suitable surface coating to aid the bedding in. If Wenz have been routinely using steel cams on steel buckets then they should have an approach that works reliably.

Once you select a cam then you can decide a compression ratio - Wenz and the cam supplier should be able to help in this decision. Your 93 Octane premium unleaded is similar to our 98 Octane premium unleaded. With the sort of cam I mentioned previously you should be able to do 10.5 to 11 comp ratio. With computer controlled ignition timing and knock sensor maybe even a bit higher

cheers
Rohan
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PostPost by: cabc26b » Tue Apr 14, 2015 10:00 pm

Bill,

When I built my motor I had John McCoy at omnitech do the head - he talked me into the pump and I used this as the basis for my wet sump system. as i understand it , flow is suppose to be one of the advantages of the Johnson pump .

FWIW - I used the foot well location for the tank on my last racing élan , as short lines were preferable over weight in the trunk.

Regards,

George
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PostPost by: bill308 » Sat May 02, 2015 10:29 pm

Thanks George.

What was your oil tank like? Rectangular, with several perforated planes to de-aerate the oil?

I got a call from Peter Marcovicci yesterday evening saying my engine was on the dyno and had spark. The Electromotive xdi-2, programmable ignition, was not yet programmed, so I was a little surprised that it created a spark at all. The xdi-2 is a crank triggered, waste spark (1-spark per rev per cylinder) system, which I also use on my carb 308. We agreed that it would be good if I could come out and use my laptop to program the advance curve for the initial start, to save Peter from having to install the software on his laptop and come up to speed programing wise. This could save a few shekels.

This morning my friend Tim and I drove out to Long Island with my laptop and an ignition advance program that started at 12 degrees BTDC, up to 1000 engine rpm, then advanced to 32 degrees BTDC at 3500 rpm and lasted up to 8000 rpm, at which time, timing would fall off to 20 degrees at 9500 rpm, sort of a rev limiter. I loaded the advance curve into the xdi-2 and Peter started the engine for the first time. It's alive! We couldn't confirm timing with a timing light, as both the timing lights we tried, were apparently inoperative.

I think we got about a half hour running on the engine, enough to break in the cams, get the engine up to temperature (to do a re-torque), do a rough balance on the carbs, and do a couple of dyno pulls up to about 6000 rpm. We saw about 145 bhp at 6000 rpm on the first pull. When we changed total advance from 32 to 26 BTDC and did another pull, we saw about 160 bhp. We need to get a timing light on the engine and confirm the actual timing.

When all is done, Peter expects about 200 bhp from this engine on pump gas, 91-93 (RON+MON)/2.

Qualitatively, it sounded great, but a little rough at idle, likely due to less than perfect carb balance (Peter used an SK Synchrometer on one barrel of each carb-I'll use a 4-bank manometer on the 45DCOE152G's (4-progression holes)) and a light weight (Fidanza), aluminum flywheel. The running engine had a very authoritative bark and reved very freely. We used the dyno exhaust system in total and no air box. Hopefully, we'll have the actual TTR air box and entire exhaust in about 4-weeks, when my 26R body and chassis arrive in Newark, NJ.

There were no visible oil leaks.

I plan to dive out for the next tuning session on Tuesday, 5/5/15.

Wish me luck,
Bill
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