Wife finally gave the green light to go all out on the shark. Starting with the engine. Just got a good '85 5.0L complete bottom end. Already have a set of headers. Ordering Euro S heads from 928intl Monday. Having cams custom ground for a "little" more agression than the stock "S" cams. Using a set of 79 cams to be welded and ground so I don't have to sacrifice my "S" cams. Current "S" block, heads and cams will be a spare in case I grenade the new engine..

Couple quick questions.
1. Who has already built a hybrid that might be available for PM's?
2. I want to go with the 928MS super charger/intercooler 1st of next year. What would be the best way to lower compression a little now to help future boost issues?
3. What are the limits of power a stock 5.0L bottom end can handle? Bottom end had about 70K on it when pulled. I plan on keeping my nitrous with the supercharger at about +75HP WOT. Nitrous has a double effect on S/C engines acting as a super intercooler as well. If used in a reasonable amount it will actually alloow you to use less retard under boost, with more power and better intake charge cooling.
4. Am I on the money, thinking the Hybrid motor with slightly more agressive than "S" cams, plus headers (no cats) will put out 360+ hp at the crank?
5.With S/C and 75hp nitrous, what clutch pack would be best for street/autocross use? I see Karl has a couple different stages. Don't want to go on HP rating alone as I don't want to loose drivability.
6. As long as I have the 5.0L out, what PM type items should I look at prior to assembly and install?

This is my summer-fall project, I plan on documenting the build as much as possible for future hybrid builders. I'll post it on my rennlist page as soon as I make one..

Thanks!

 

go check my posts on the 5 liter hybrids that i have built. most recently, scot's.
you are looking at 290ish rwhp with Ljet and probably 300rwhp with CIS if you have it tuned corrrectly.
if you have it out, it is probably worth doing a refresh on rings and bearings and seals. just putting back in is a little risky, unless you know the absolute history of the engine. I think at least pull the rod bearings and replace them if they look suspect. (thats easy to do)

the only way to reduce the compression would be to notch the pistons a little deeper and wider.
by the way, what are you planning to do with notching the pistons. I have the templates you can use to do this if you need them. with just the euro 85 notches, CCs of the pistons are near 8cc for a near 10:1 compression. if you make the valve reliefs wider and deeper, you could drop this to 9:1 pretty easily.

mk

 

Thanks Mark! I would love the templates. Running CIS.

 

If you're going to boost it, I'd say skip the hybrid and just install US pistons in your 4.7L block. Far less work and it will be much easier to boost. John Kuhn got mid-300s hp with his brother's engine. Basically it's a 4.7L US bottom (custom pistons shaped like US pistons), 84-86 Euro S heads and intake, 78-79 cams, and twin turbos (9psi?). He wasn't pushing the boost close to what he could have. That combo would give you 8.1-8.5:1 compression versus mid-high 9:1 range for the hybrid.

 

David Lloyd in the Owners club, Stan Shaw, John V, I believe have all built the motors.
Send a shout out to all Hybrid Ninja masters!

 

Subscribing to learn more.

$0.00002: I vote go 5.0 (300 CCs is more power, and a good thick block according to some people) with valve notches in pistons per Mark's experienced recommendations.

Centrifugal SC + Nitrous = very, very careful tuning.

 

Sounds interesting. Why the US cams instead of EURO S? I know the US pre 79 cams are more agressive than the 80-84, but they still have less duration and lift than the "S" cams. Also only mid 300's with twin turbos?

My goal is to have mid 500's rear wheel when done. Low 300's RWHP with the Hybrid. S/C w/intercoller should net mid to high 400's on CIS (pushing the limits of the CIS). Nitrous bump for 75hp more will give closer to 100hp under boost and put me mid 500's. Since nitrous has fuel supply seperate from CIS, I can use it to go beyond limitations of CIS. With a beefed up clutch and 5-speed it should be nuts. And for less than the price of upgrading to a nice S4.

 

John said he went with the 78-79 cams because he wanted to be conservative on the valve timing and because he had sold the cams that came with the Euro S heads. The build was done on a budget and he didn't want to do it over again if the 84-86 cams were too aggressive.

The turbos he used were the original Callaway early 80's IHIs with slightly updated compressor and turbine wheels in them. By mid-300s I mean somewhere around 350. It may have been higher or lower but I don't remember. It wasn't properly tuned yet and the boost was rather low for how overbuilt John's engines are. I think it was only 8 or 9psi of boost, compared to 11 or 12 for a 951 with similar compression. The engine is about 8.2:1 compression which would be the same as using stock US pistons in place of his forged pistons.

 

you still need to notch the US pistons as well, as we are talking about 45mm valves vs 43mm!! so, while you are notching them make them wider to lower compresssion, as someone said, 300ccs !!!!! we got 40hp for that alone!!!!! (no other changes)

cams we use normally are 83 euro, but devek B1s work and you can make something close with the US 79 cams but you need to do the valve caps. I would just do euro cams and call it a day!

mk

 

one other quick note. you leave all the pistons the same as stock on the passenger side of the engine. reverse the driver side to optimize rod to piston angle. probably why scots eng was even stronger than the one i first built, even though he had a more restrictive exhaust and no where near the right ignition advance. 36 degrees with scots 82 Ljet vs my optimized 44degrees i was able to get with my old 84 Ljet.

MK

 

Mark, as usual, you are ignoring what somebody else wants to do with their engine and telling them what you would do for your situation (NA race engine). You may or may not need to notch the pistons depending on how close you want the interference tolerances. You would have to create huge notches to get a 5L hybrid close to the CR of a 4.7L US. With large 8cc notches, you're at 9.12:1 versus around 8.2:1 for the 4.7US. Do you really want to cut that deep into a piston on a boosted engine? Adding 6% to displacement when you can't run close to as much boost due to increased CR makes no sense.

BTW 40hp/300cc would make a 5L engine 666hp... NA... BS.

 

cylinder walls aren't much if any thinker on a 5L versus a 4.7L. The difference is diameter of the cylinder tower. IIRC normal cylinders are 109-111mm for 97mm bore versus 112-114mm for 100mm bore. Erkka can definitely answer that better than I can.

So you're voting to add sharp machined edges on the pistons and higher compression to that equation?

 

Mike,

I bought JohnVs hybrid engine about a year and a half ago. Once I was able to convert the racing setup he had to more of a stock setup, the engine produces plenty of power. More than I ever would need. (I think!!)

928 Drilled Crank
GTS Oil Baffle
85 Pan
85 Pistions
85 Block
Euro S Throttle Body
Euro S Runners
Euro S Heads
Euro S Cams (John said he got his tuned by Elgin)
All of the above parts came from a 4.7 80 Euro S engine.

FWIW, I had to do some slight modifications to the block to fit the rubber motor mounts and use the engine shock mounts. Easy but did require some extra time.

 

951 pistons...superbst

 

flyingdog, please do a little homework yourself and try and read what was posted. we are talking about the potential to boost a 5 liter mildly on a street application. 9:1 could work out well. Also, if you wanted to make the notches much wider, not deeper (you must have missed that part) you could drop the compression to a milder level. It was just a suggestion, as it seemed to be a though after it was built, to be boosted. If it is a primary goal then yes, maybe custom pistons would be the answer. the solution certainly wouldnt be to use a 4.7 when you could use a 5 liter.

Now, a little reality check. keep in mind, this is a width, not a stroke change and the effects are a little different. yes, 300ccs, and NO other changes with scots car went from 220 with a 4.5, to 250 with the 4.7 and 290rwhp with the 5 liter. THEN, i did the exact same thing, with one small change in valve size and compression. 235 to 293rwhp. (ie 4.7 US with all euro stuff, going to a 5 liter and the euro heads). most all 4.7s, even euro make near 260rwhp , while our 5 liter , even with the restrictive AFM Ljet, makes 290+rwhp.

if you could continue to bore out unlimited, you would see more HP gains than just stroke alone for a given CC change. another data point is the 5.4 liter vs the S4. look how 400ccs gives the car 35hp over the S4 counterpart.
with your silly math, thats 500hp. a few other factors are left out in that calculation that dont allow it to work.

Mk