New project. 1987 Lamborghini Jalpa. There's no easy way out.

corsepervita wrote: The factory claims 255hp but I've seen a Jalpa recently dyno'd that came in under 200hp. Not sure if that's due to running poorly, skewed numbers from the factory or what.

Fictional numbers from an Italian Exotic car manufacturer in the 80's !!! No, Never, the shoch, oh the humanity!!

Remember they claimed that Countach could do 200mph back in the early 80's. 180 would have been a stretch. I think most performance figures back then were carefully calculated based on what sounded about right. The good news is if you are building it carefully, cleaning up the heads, skimming the head and block as you build it, eliminating some parasitic drag as you go with the smog pump and things I bet an honest 250+ at the crank is entirely feasible.

Adrian_Thompson wrote:

corsepervita wrote: The factory claims 255hp but I've seen a Jalpa recently dyno'd that came in under 200hp. Not sure if that's due to running poorly, skewed numbers from the factory or what.

Fictional numbers from an Italian Exotic car manufacturer in the 80's !!! No, Never, the shoch, oh the humanity!! Remember they claimed that Countach could do 200mph back in the early 80's. 180 would have been a stretch. I think most performance figures back then were carefully calculated based on what sounded about right. The good news is if you are building it carefully, cleaning up the heads, skimming the head and block as you build it, eliminating some parasitic drag as you go with the smog pump and things I bet an honest 250+ at the crank is entirely feasible.

Hahahaha right? They would never inflate numbers at the factory

I agree though, I think with good machine work and modern materials it's feasible. I do indeed planning on eliminating the pump since I purchased a euro exhaust anyway (which has no machining in it for the feed tubes from the pump).

Wow, all that 'neat' for 200 hp? Give those heads some work. Any way you have access to cam or compression information?

tuna55 wrote: Wow, all that 'neat' for 200 hp? Give those heads some work. Any way you have access to cam or compression information?

Yeah, I can pull it from the build manual later this evening. Give me a list of things you'd like to know and I'll put down numbers for you. Tolerances and specs are well documented in the manual I found.

corsepervita wrote:

tuna55 wrote: Wow, all that 'neat' for 200 hp? Give those heads some work. Any way you have access to cam or compression information?

Yeah, I can pull it from the build manual later this evening. Give me a list of things you'd like to know and I'll put down numbers for you. Tolerances and specs are well documented in the manual I found.

Piston weight

Compression ratio (static)

Bore/stroke

cam specs (does this thing have rockers? then rocker ratios)

Just curious again, don't make yourself crazy looking for it.

tuna55 wrote:

corsepervita wrote:

tuna55 wrote: Wow, all that 'neat' for 200 hp? Give those heads some work. Any way you have access to cam or compression information?

Yeah, I can pull it from the build manual later this evening. Give me a list of things you'd like to know and I'll put down numbers for you. Tolerances and specs are well documented in the manual I found.

Piston weight Compression ratio (static) Bore/stroke cam specs (does this thing have rockers? then rocker ratios) Just curious again, don't make yourself crazy looking for it.

Mass of each valve too??

Ok here we go.

• Compression ratio: 10:1 so sayeth the manual, but I've read elsewhere it's actually 9:1, however, this manual is a mixture of Urraco/Silhouette/Jalpa.
• Displacement: 3.5L (86mm bore size, kinda funny since my little Porsche 924 is 86.5mm)
• Stroke: 75mm
• No rockers. It's a shim over bucket design.
• Camshaft labels discharge as initial opening 60 BDC, final closing at 32 after TDC and duration opening 272 degrees. Suction initial opening at 32 BTDC, final closing 60 after BDC and duration opening 272 degrees.

Using the camshaft calculator on wallaceracing.com with these numbers confirms the duration. http://www.wallaceracing.com/camcalc.php

No specific data I can find on the gram count for valves, I can weigh those though once I get back to the machine shop.

corsepervita wrote: Ok here we go. - Compression ratio: 10:1 so sayeth the manual, but I've read elsewhere it's actually 9:1, however, this manual is a mixture of Urraco/Silhouette/Jalpa. - Displacement: 3.5L (86mm bore size, kinda funny since my little Porsche 924 is 86.5mm) - Stroke: 75mm - No rockers. It's a shim over bucket design. - Camshaft labels discharge as initial opening 60 BDC, final closing at 32 after TDC and duration opening 272 degrees. Suction initial opening at 32 BTDC, final closing 60 after BDC and duration opening 272 degrees. Using the camshaft calculator on wallaceracing.com with these numbers confirms the duration. http://www.wallaceracing.com/camcalc.php No specific data I can find on the gram count for valves, I can weigh those though once I get back to the machine shop.

Thanks for digging that up.

Some basics from an amateur.

If it's 9:1 and there was a 10:1 option, you can probably get those pistons. You could also probably get custom ones made relatively inexpensively with some more modern touches and a more modern ring package.

I'll bet you're losing a lot of horsepower in those heads. Find a good guy and turn him loose.

I'm dying to see this mill back together.

corsepervita wrote:

Adrian_Thompson wrote: Yup, Berkley = F bomb. Bob Costas = P word slang for female genitalia. E36 M3 = S word and Shiney Happy Person = A hole. You have to love someone with social anxiety owning a one of less than 500 80's Italian Supercar

LOL! I've seen a few forums use substitution words. Makes reading more entertaining.

You'll know you've been here awhile when you start using "berk" in regular conversation. "Ah, berk-it!" for example.

Great build!

I'd be tempted to talk to some cam people as well. See if there's an option that might be relative reasonable budget wise.

I think we're all dying to see as many pictures as you're willing to take! Looks like you're using photobucket. You could put them all in a single public folder and share the link instead of tagging all of them in this thread.

tuna55 wrote:

corsepervita wrote: Ok here we go. - Compression ratio: 10:1 so sayeth the manual, but I've read elsewhere it's actually 9:1, however, this manual is a mixture of Urraco/Silhouette/Jalpa. - Displacement: 3.5L (86mm bore size, kinda funny since my little Porsche 924 is 86.5mm) - Stroke: 75mm - No rockers. It's a shim over bucket design. - Camshaft labels discharge as initial opening 60 BDC, final closing at 32 after TDC and duration opening 272 degrees. Suction initial opening at 32 BTDC, final closing 60 after BDC and duration opening 272 degrees. Using the camshaft calculator on wallaceracing.com with these numbers confirms the duration. http://www.wallaceracing.com/camcalc.php No specific data I can find on the gram count for valves, I can weigh those though once I get back to the machine shop.

Thanks for digging that up. Some basics from an amateur. If it's 9:1 and there was a 10:1 option, you can probably get those pistons. You could also probably get custom ones made relatively inexpensively with some more modern touches and a more modern ring package. I'll bet you're losing a lot of horsepower in those heads. Find a good guy and turn him loose. I'm dying to see this mill back together.

agree with most of this....

I've recently had an 86mm bore adapter made for my bench....

photo of bore adapter

Oh... here is a photo of my bench checking the flow on a Toyota 7MG head.

Those rods look kind of meaty... a shop should be able to lighten them. I'd go higher on the compression with a 272 duration camshaft. I'd be looking closer to 11 to 1 .
As an example, I'm currently building a 4AGE with 240 duration cams and I'm using 10.7 to one as static.

Finally... not entirely sure... but the valve seats look a bit wimpy (thinn from ID to OD). While you are getting the head repaired you might look at installing new seats... it might make optimizing port flow easier as well....

BTW... as others have said already... I too had a thing for the Jalpa (I pronounce - Yalpa). The Countach always was just too extreme... the Jalpa always seemed to be a good blend of exotic and daily-able.

As to valve mass.... I'm thinking you might be able to shave a great deal of valve mass utilizing newer materials. You also might be able to run a thinner stem allowing for additional flow.

corsepervita wrote: - Displacement: 3.5L (86mm bore size) - Stroke: 75mm

oldeskewltoy wrote: As to valve mass.... I'm thinking you might be able to shave a great deal of valve mass utilizing newer materials. You also might be able to run a thinner stem allowing for additional flow.

with such a short stroke... and a pretty big bore in relation to the stroke this engine is only limited by the chain cam drive and and the valve train mass.

A 272 duration cam can likely twist upto about 8000, maybe 8500. Btw, any other duration numbers? Usually measured @ either .040", or .050" of lift.

What is the factory redline??

oldeskewltoy wrote: agree with most of this.... I've recently had an 86mm bore adapter made for my bench.... photo of bore adapter Oh... here is a photo of my bench checking the flow on a Toyota 7MG head. Those rods look kind of meaty... a shop should be able to lighten them. I'd go higher on the compression with a 272 duration camshaft. I'd be looking closer to 11 to 1 . As an example, I'm currently building a 4AGE with 240 duration cams and I'm using 10.7 to one as static. Finally... not entirely sure... but the valve seats look a bit wimpy (thinn from ID to OD). While you are getting the head repaired you might look at installing new seats... it might make optimizing port flow easier as well.... BTW... as others have said already... I too had a thing for the Jalpa (I pronounce - Yalpa). The Countach always was just too extreme... the Jalpa always seemed to be a good blend of exotic and daily-able. As to valve mass.... I'm thinking you might be able to shave a great deal of valve mass utilizing newer materials. You also might be able to run a thinner stem allowing for additional flow.

oldeskewltoy wrote: As to valve mass.... I'm thinking you might be able to shave a great deal of valve mass utilizing newer materials. You also might be able to run a thinner stem allowing for additional flow. with such a short stroke... and a pretty big bore in relation to the stroke this engine is only limited by the chain cam drive and and the valve train mass. A 272 duration cam can likely twist upto about 8000, maybe 8500. Btw, any other duration numbers? Usually measured @ either .040", or .050" of lift. What is the factory redline??

The valve seats do indeed seem wimpy. I'm actually going to replace them all. I told my machinist I wanted to update to modern materials and get them flowed. He recommended better (potentially larger, for slightly larger valves) seats, which I'm fine with. So that is in the works. Issue is primarily finding some that fit.

I planned on replacing the pistons with some JE Pistons (others have had great success with them on the Jalpa motors). The rods are indeed fairly beefy. They are the later generation rods and "reinforced" compared to the early rods (so I've been told).

Agreed with the Jalpa blend of daily and exotic. It's a hydraulic setup for the clutch, as well as a BMW M5 clutch setup, so it's far more forgiving. The brakes are also BMW. They're a neat compromise in my opinion. They still retain a manual steering rack, which I prefer cars with manual steering.

I'll have to find out what the mass of the old valves are. I should be meeting with my machinist this next week or the week after if he isn't busy. I'll have him weigh them. I planned on replacing the valves with Manley Performance valves. My understanding is that the dodge viper valves are nearly the same size and require minor machining to make them fit the Jalpa. Although when I called Manley, they said they just cut and machine them there with a custom order, and their prices were incredibly reasonable for the stainless valves, so that seems unnecessary. Though I suspect those might be heavier than the sodium filled valves. Not sure till I weigh them.

Word also has it that replacement springs are as simple as using LS1 springs (more research needed though). One of the guys on lamborghini-talk used the LS1 springs in his recent rebuild and reported it's slightly more pressure than OEM, but not enough to wipe the cam. Hell of a lot cheaper than the old OEM stuff, and seems like that'd be an easy route to go since parts are easy to find.

I don't have any other numbers in the manual on the cams. I'll see if I can get my machinist to grab those numbers as well. Factory redline is 7500rpm.

Can you get titanium valves to keep the mass down like the old sodium filled valves? Steel valves will add a lot of mass that isn't such a good idea if you want to rev more.

Maybe call ED Curtis at FlowTech Induction?

Dude is supposed to be the CAM savant for most v8's.

http://www.flowtechinduction.com/

Last I heard he is one of the few shops that has the software to custom design the cam based on a custom engine... (like the OEM's use.)

Also, what's the rest of the valvetrain like? Are there better springs you can adapt from the aftermarket? Recent high RPM based domestic V8s have spawned a whole industry of lightweight valvetrain parts.

Adrian_Thompson wrote: Can you get titanium valves to keep the mass down like the old sodium filled valves? Steel valves will add a lot of mass that isn't such a good idea if you want to rev more.

Yeah, if I recall, Manley Performance has the option for SS valves as well as titanium. Costs more, but keeping mass down is a good idea. I haven't priced out the titanium valves.

Mad_Ratel wrote: Maybe call ED Curtis at FlowTech Induction? Dude is supposed to be the CAM savant for most v8's. http://www.flowtechinduction.com/ Last I heard he is one of the few shops that has the software to custom design the cam based on a custom engine... (like the OEM's use.)

That sounds pretty cool, i'll have to check it out. What is the software for? Just algorithms for lift and duration based on engine numbers?

tuna55 wrote: Also, what's the rest of the valvetrain like? Are there better springs you can adapt from the aftermarket? Recent high RPM based domestic V8s have spawned a whole industry of lightweight valvetrain parts.

Yeah, supposedly (I need to research more), LS1 springs will fit. So in theory, the aftermarket available for those springs should be available for me. Again, I need to measure and find out more to ensure.

It'll be interesting to see what can be made with modern day materials.

Ed will actually want more information than just the current cam, he'll want to know peak hp and torque desires (RPM), use for the vehicle, weight of the vehicle, timing preferences, etc.

If you ask about a "cam sound" he'll probably hang up on you. I'd advise a call. Usually it costs around 350 bucks to have Ed spec a cam out for you. Cost may be different for a truly custom engine he might not have worked on. He'd probably be able to answer if ls springs fit by giving him the spec of the existing springs etc. I've heard he is amazing to talk to on the phone but have ALL your reference material in front of you as he gets a LOT of calls a day and doesnt have time to hold while you go dig up that book you think you have that might have the information he needs.

Dad has Weber Cams in his 911 so they may be a good candidate as well but expect more dollares. http://www.webcamshafts.com/

Mad_Ratel wrote: Ed will actually want more information than just the current cam, he'll want to know peak hp and torque desires (RPM), use for the vehicle, weight of the vehicle, timing preferences, etc. If you ask about a "cam sound" he'll probably hang up on you. I'd advise a call. Usually it costs around 350 bucks to have Ed spec a cam out for you. Cost may be different for a truly custom engine he might not have worked on. He'd probably be able to answer if ls springs fit by giving him the spec of the existing springs etc. I've heard he is amazing to talk to on the phone but have ALL your reference material in front of you as he gets a LOT of calls a day and doesnt have time to hold while you go dig up that book you think you have that might have the information he needs. Dad has Weber Cams in his 911 so they may be a good candidate as well but expect more dollares. http://www.webcamshafts.com/

LOL in my experience most people that ask about that also are the types that ask a dyno tuner if they can tune their car to shoot flames. So I can't really blame him. Great info thank you. I'll try and get more information available and then give him a call when that time comes.

Well, bottom end is ready to be sent to the machine shop. Left a few messages for him, hasn't returned my messages which is unlike him. Guessing he is either out of town, on vacation, or on jury duty. Will try to see if he's around tomorrow to drop off the block.

A few interesting notes:

• The block was so light, it came off the stand with my bare hands, no hoist required. I noticed when I released the pinch bolt to rotate it, it wiggled with ease. I thought "huh, that seems... effortless." hardly weighs a thing.
• One of the pistons had rings that were stuck and I thought the machinist was going to have to disassemble the bottom end. I ended up "making a tool" (bench grinder + 12mm wrench) to fit and slip past the block so I could get the rod bolts off. It worked.
• The crankshaft looks to be in great shape, the bearings are all accounted for.
• It's pretty neat how the sleeves/cylinder assemblies all come out with ease. It's going to make assembly really easy when it comes time.

Taken apart, getting ready to come off the stand.

Off we go!

That crank looks chunky. How much does it weigh?

Wow. I'd never even consider pulling an engine from a Lambo much less disassemble one. It's way past my skill and comfort level. I'm eagerly following your build.

I saw a red Jalpa parked on the side of Woodward Ave in Ferndale Mi (Just north of Detroit for the non locals) last night. First one I've ever seen in the wild. Unfortunately I was driving with two other cars following so couldn't stop and get a pic.

My daughter just moved to Fabulous Ferndale. And got a great job at Chrysler, says captain boastfull.

akylekoz wrote: My daughter just moved to Fabulous Ferndale. And got a great job at Chrysler, says captain boastfull.

Cool. Where has she/ you come from? My daughter lives in our rental in Fendale, she moving out so I'm doing some rehabbing to rent.