HIGHWAYMAN: Bringing the Devore 928 back from the dead
03-13-2017, 01:56 PM
#602
Developer
Couple pics... one is of your new head studs installed, the other is a look at your stroker crank scraper and windage tray system just before the oil pan goes on.
03-13-2017, 10:52 PM
#604
Banned
Thread Starter
Next up was running a 2 gauge main line to a bus bar located up forward. Devore had already wired an external safety cutoff switch that can be actuated two ways:
1) driver actuated, with a plastic key in the driver footwell
2) first responder actuated, with a pull cable mounted on the cowl.
I wanted to preserve this because it works slick and is real simple. In order to do so, I had to connect a line downstream of this switch that would power my main bus.
Devore made a cool aluminum skid plate to protect this connecting point. I drilled a hole, ran my 2 gauge through, and connected it to the common side of his switch.
In this case i used a grommet, but in cases like this, i also like to double up by coating the grommet in SEM Seam Sealer which dries very hard but flexibly. This is to prevent the grommet from moving and also from having the line move within the grommet.
Next I split loomed the line, crimped on a lug, and connected it to my Blue Sea heavy duty bus bar with plastic cover, which I mounted in the passenger footwell.
Now, I basically have 100% clean battery power up forward, and will connect EVERYTHING to this bus bar; ECU, fuel pumps....everything except fire suppression.
2 gauge means i won't have any real voltage drop, and everything will be securely mounted to a beefy bus bar which leaves lots of room for expansion. Lastly, one flick of the safety switch between my legs or one pull of the external cord shuts it all off.....
1) driver actuated, with a plastic key in the driver footwell
2) first responder actuated, with a pull cable mounted on the cowl.
I wanted to preserve this because it works slick and is real simple. In order to do so, I had to connect a line downstream of this switch that would power my main bus.
Devore made a cool aluminum skid plate to protect this connecting point. I drilled a hole, ran my 2 gauge through, and connected it to the common side of his switch.
In this case i used a grommet, but in cases like this, i also like to double up by coating the grommet in SEM Seam Sealer which dries very hard but flexibly. This is to prevent the grommet from moving and also from having the line move within the grommet.
Next I split loomed the line, crimped on a lug, and connected it to my Blue Sea heavy duty bus bar with plastic cover, which I mounted in the passenger footwell.
Now, I basically have 100% clean battery power up forward, and will connect EVERYTHING to this bus bar; ECU, fuel pumps....everything except fire suppression.
2 gauge means i won't have any real voltage drop, and everything will be securely mounted to a beefy bus bar which leaves lots of room for expansion. Lastly, one flick of the safety switch between my legs or one pull of the external cord shuts it all off.....
03-17-2017, 01:04 AM
#605
Archive Gatekeeper
Rennlist Member
Rennlist Member
Interesting day today at Gregs- I was in the back (inner?) half of the shop looking for some interior pieces and came across a couple of engine bits I hadn't seen before. Greg had gotten them as part of a cache of parts from Anderson a while back. One block caught my eye, there was light surface rust on the bores. The cylinder towers were completely gone, replaced with steel sleeves. No crank, but some (failed) Carrillo rods and Ross pistons.
I'd recently posted the PDF of the 1990 'Highwayman' article in this thread, and there's a section that talks about the three short blocks that DeVore had built, 4.8, 5.7, and 6.2 liters. He says that the 6.2 is Chevy dimensions, 4.155 x 3.48". The bores in this block are 105.6 mm, which is 4.16 inches. I didn't measure the rods and compression height, but it would be easy enough to approximate the stroke from that and the deck height, I bet it's 89mm, or 3.48".
The Ross pistons have two enormous valve reliefs in them, and DeVore mentions for the 6.2L that he had to go to Carrillo rods for clearance on the girdle.
In any case, Adam, I think Greg has the original 6.2L Highwayman block described in the 1990 Excellence article. Not sure who else would have been making 16V 6.2L steel sleeved strokers out of 4.5L blocks (?)
By any chance did any of Devore's receipts or paperwork come with the car? The engine serial # is from an '82 5-speed, M28/15 81C0447, if that's written down anywhere.
Bigass steel cylinder bores:
Bottoms, lower welded baffle in oil chimney, and whatever goo is sealing the cylinder towers in:
Engine S/N and upper welded baffle plate:
I'd recently posted the PDF of the 1990 'Highwayman' article in this thread, and there's a section that talks about the three short blocks that DeVore had built, 4.8, 5.7, and 6.2 liters. He says that the 6.2 is Chevy dimensions, 4.155 x 3.48". The bores in this block are 105.6 mm, which is 4.16 inches. I didn't measure the rods and compression height, but it would be easy enough to approximate the stroke from that and the deck height, I bet it's 89mm, or 3.48".
The Ross pistons have two enormous valve reliefs in them, and DeVore mentions for the 6.2L that he had to go to Carrillo rods for clearance on the girdle.
In any case, Adam, I think Greg has the original 6.2L Highwayman block described in the 1990 Excellence article. Not sure who else would have been making 16V 6.2L steel sleeved strokers out of 4.5L blocks (?)
By any chance did any of Devore's receipts or paperwork come with the car? The engine serial # is from an '82 5-speed, M28/15 81C0447, if that's written down anywhere.
Bigass steel cylinder bores:
Bottoms, lower welded baffle in oil chimney, and whatever goo is sealing the cylinder towers in:
Engine S/N and upper welded baffle plate:
03-17-2017, 11:27 AM
#606
Captain Obvious
Super User
Super User
I had a project car years ago that needed and engine change. So decided to remove the oil pan and run the engine "Slick 50" style. It was cool and freaky to see the bottom end spinning at 3K rpms with no oil pan. Thought it would lock up in seconds or launch a con rod to the moon but it ran for several minutes without any drama so I shut it down when it got boring to watch.
03-17-2017, 11:50 AM
#607
Banned
Thread Starter
Interesting day today at Gregs- I was in the back (inner?) half of the shop looking for some interior pieces and came across a couple of engine bits I hadn't seen before. Greg had gotten them as part of a cache of parts from Anderson a while back. One block caught my eye, there was light surface rust on the bores. The cylinder towers were completely gone, replaced with steel sleeves. No crank, but some (failed) Carrillo rods and Ross pistons.
I'd recently posted the PDF of the 1990 'Highwayman' article in this thread, and there's a section that talks about the three short blocks that DeVore had built, 4.8, 5.7, and 6.2 liters. He says that the 6.2 is Chevy dimensions, 4.155 x 3.48". The bores in this block are 105.6 mm, which is 4.16 inches. I didn't measure the rods and compression height, but it would be easy enough to approximate the stroke from that and the deck height, I bet it's 89mm, or 3.48".
The Ross pistons have two enormous valve reliefs in them, and DeVore mentions for the 6.2L that he had to go to Carrillo rods for clearance on the girdle.
In any case, Adam, I think Greg has the original 6.2L Highwayman block described in the 1990 Excellence article. Not sure who else would have been making 16V 6.2L steel sleeved strokers out of 4.5L blocks (?)
By any chance did any of Devore's receipts or paperwork come with the car? The engine serial # is from an '82 5-speed, M28/15 81C0447, if that's written down anywhere.
Bigass steel cylinder bores:
Bottoms, lower welded baffle in oil chimney, and whatever goo is sealing the cylinder towers in:
Engine S/N and upper welded baffle plate:
I'd recently posted the PDF of the 1990 'Highwayman' article in this thread, and there's a section that talks about the three short blocks that DeVore had built, 4.8, 5.7, and 6.2 liters. He says that the 6.2 is Chevy dimensions, 4.155 x 3.48". The bores in this block are 105.6 mm, which is 4.16 inches. I didn't measure the rods and compression height, but it would be easy enough to approximate the stroke from that and the deck height, I bet it's 89mm, or 3.48".
The Ross pistons have two enormous valve reliefs in them, and DeVore mentions for the 6.2L that he had to go to Carrillo rods for clearance on the girdle.
In any case, Adam, I think Greg has the original 6.2L Highwayman block described in the 1990 Excellence article. Not sure who else would have been making 16V 6.2L steel sleeved strokers out of 4.5L blocks (?)
By any chance did any of Devore's receipts or paperwork come with the car? The engine serial # is from an '82 5-speed, M28/15 81C0447, if that's written down anywhere.
Bigass steel cylinder bores:
Bottoms, lower welded baffle in oil chimney, and whatever goo is sealing the cylinder towers in:
Engine S/N and upper welded baffle plate:
Wow,
I'm a little speechless right now. To answer your question, no, not a shred of paper came with the car. Remember, I bought it from a lien sale basically, so I am guessing that if any paper exists, Maverick has it. Bisimoto gave me everything they had, but there was no documentation.
I guess the natural questions I would have to this find would be:
1) what does Greg know about it
2) If these parts came from Mark, he should know about it.
It MAY not be "the motor", but it probably is, just by looking at it. Obviously too far gone to bring to life, but still really, really cool to find.
Great find Rob!
03-17-2017, 12:45 PM
#608
Developer
I've built a wet-wall 7.0L motor (4.250 bore) for a customer but all he wanted was the short block/rotating assembly. He had his own ideas about heads, valves, and cams.
I'd love to build a complete 7.0L motor, I think we have answers for the challenges in the intake and heads and cams that a 7.0L 928 would demand.
I wonder what the cause of the failed Carrillo rods is. Maybe somebody knows the failure story.
I'd love to build a complete 7.0L motor, I think we have answers for the challenges in the intake and heads and cams that a 7.0L 928 would demand.
I wonder what the cause of the failed Carrillo rods is. Maybe somebody knows the failure story.
03-17-2017, 01:50 PM
#609
Banned
Thread Starter
Meh, I guess.
I went through this when building up the Camaro (6.2, 378ci). There was a lot of thought about going to 7L (427 ci), but at the end of the day, in a boosted application, the extra cubes really didn't matter vis a vis the price point required to get there. I suspect even in an NA application, the difference wouldn't be that great.
In the Chevy world, a well built NA 6.2 puts out around 435hp. The ZO6, which was a 7L NA motor (previous gen), puts out 505hp. Not a huge difference imho.
I suspect that a 6.57 vs a 7L 928 would be even narrower of a spread, and even less significant for the cost it would take to make a 427 928.....
I went through this when building up the Camaro (6.2, 378ci). There was a lot of thought about going to 7L (427 ci), but at the end of the day, in a boosted application, the extra cubes really didn't matter vis a vis the price point required to get there. I suspect even in an NA application, the difference wouldn't be that great.
In the Chevy world, a well built NA 6.2 puts out around 435hp. The ZO6, which was a 7L NA motor (previous gen), puts out 505hp. Not a huge difference imho.
I suspect that a 6.57 vs a 7L 928 would be even narrower of a spread, and even less significant for the cost it would take to make a 427 928.....
03-17-2017, 02:02 PM
#610
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
rod issues
I've built a wet-wall 7.0L motor (4.250 bore) for a customer but all he wanted was the short block/rotating assembly. He had his own ideas about heads, valves, and cams.
I'd love to build a complete 7.0L motor, I think we have answers for the challenges in the intake and heads and cams that a 7.0L 928 would demand.
I wonder what the cause of the failed Carrillo rods is. Maybe somebody knows the failure story.
I'd love to build a complete 7.0L motor, I think we have answers for the challenges in the intake and heads and cams that a 7.0L 928 would demand.
I wonder what the cause of the failed Carrillo rods is. Maybe somebody knows the failure story.
03-17-2017, 02:21 PM
#611
Nordschleife Master
SOP for Carrillo rods was to use a Chevy rod....which used a wrong offset for bore spacing..so the Small end was offset on the wrist pin Created huge stress issues. Thankfully that was recognized by Greg Brown and Carrillo. So a basic stroker design flaw which was carried forward for many , many years....
03-17-2017, 02:37 PM
#612
Nordschleife Master
Meh, I guess.
I went through this when building up the Camaro (6.2, 378ci). There was a lot of thought about going to 7L (427 ci), but at the end of the day, in a boosted application, the extra cubes really didn't matter vis a vis the price point required to get there. I suspect even in an NA application, the difference wouldn't be that great.
In the Chevy world, a well built NA 6.2 puts out around 435hp. The ZO6, which was a 7L NA motor (previous gen), puts out 505hp. Not a huge difference imho.
I suspect that a 6.57 vs a 7L 928 would be even narrower of a spread, and even less significant for the cost it would take to make a 427 928.....
I went through this when building up the Camaro (6.2, 378ci). There was a lot of thought about going to 7L (427 ci), but at the end of the day, in a boosted application, the extra cubes really didn't matter vis a vis the price point required to get there. I suspect even in an NA application, the difference wouldn't be that great.
In the Chevy world, a well built NA 6.2 puts out around 435hp. The ZO6, which was a 7L NA motor (previous gen), puts out 505hp. Not a huge difference imho.
I suspect that a 6.57 vs a 7L 928 would be even narrower of a spread, and even less significant for the cost it would take to make a 427 928.....
You mentioned boosted engines, and that's enough to get me going. For forced induction, in my opinion one should pay a lot of attention to the cylinder wall thickness and the bore area. Thin walls break once you start making real power, especially with large bore. Large bore also puts more demands on the cylinder head stiffness and fasteners. If one is boosting a 928, I'd stay with 100mm bore or close to that.
03-17-2017, 03:55 PM
#613
Rennlist Member
Porsche had the main heavy duty cable from the +ve battery terminal to feed the high current to starter and alternator. The two separate (smaller) cables to feed the engine electronics.
This helps to not have starter motor impulses interfere with the engine electronics...
This helps to not have starter motor impulses interfere with the engine electronics...
One of the few things automotive related that I have formal training in is with 12 volt systems. As a wayward kid, Dad sent me off to the local technical school where I was more or less forced to obtain a 2 year certificate in electronics engineering. It sounds fancy, but it is not a degree nor am I an engineer. It was basically a two year course on the design of 12 volt systems, batteries, soldering, wiring, and a bunch of other crap. I hated it at the time, but 25 years later I can't believe how lost I would be without a solid foundation in DC systems design.
So I normally don't sweat electrical issues in cars, and I have built more than one wiring harness from scratch. The Devore car has ZERO existing wiring, which is great because lots of race cars still have the heavy stock harness in place. In this case, Devore = blank slate, which I like the best.
Some months ago I put in an optima gel battery and box in the right rear passenger seat, left unwired for the time being.
Today was the day to begin the foundation of any DC system - the battery connections. I always do the battery first, and then branch from there.
In another career after school, I spent 10 years in the marine industry and thus the way I do things in the cars is very marine-like. For example, I am a fan of Blue Sea systems products and Ancor wiring connectors. Both are exclusively boat products, but they are WAY tougher than equivalent automotive stuff.
I don't much care how much weight the DC system adds to the car. I always go with a full sized battery and a minimum of 2/0 cables for power. Sure, it adds weight, but who wants to chase ground and power issues because you're trying to save weight.
In this case, I began by routing the old battery cable to the new location by drilling a hole in the bulkhead and putting in a grommet.
I used a Blue Sea battery disconnect for maintenance purposes. It should be noted that this off switch is NOT the emergency disconnect used by first responders. The Devore car already has such a system, with two separate disconnects, one external and one close to the driver. The switch I installed today would be upstream of that, and it's basically a maintenance and storage disconnect.
The Blue Sea stuff is overbuilt and this switch has a 1500 amp cranking rating, which is an order of magnitude more than will be needed.
Next it was time to tackle the ground. People get wrapped around the axle on grounds. In this situation, the ground can be anywhere you want it to be, so long as it's good and solid. I sanded away a convenient location, then welded a bolt directly onto the chassis for a firm, solid ground that I could bolt a battery lug to. It doesn't get much better than this for good grounds.
Finally - and this is super important - once I bolted by negative battery cable down, I immediately painted over the whole assembly with the same undercoater the interior is done in.
Corroded grounds are a MAJOR issue in a multitude of electrical problems that plague many cars. It's important to immediately protect the area from corrosion, so the paint covers everything, while the metal to metal connection is still preserved underneath.
Some of my practices are:
- always use split loom one wiring to prevent chafe
- all heavy gauge wires get hold downs as necessary
- Always use marine grade crimp on lugs with a marine crimper on battery cables.
- Cover the cable almost to the end with electrical tape to prevent corrosion
So now we have the foundation of the battery system. Now onto the accessories!
The undercoater paint in the picture hasn't laid down yet and looks lumpy.
So I normally don't sweat electrical issues in cars, and I have built more than one wiring harness from scratch. The Devore car has ZERO existing wiring, which is great because lots of race cars still have the heavy stock harness in place. In this case, Devore = blank slate, which I like the best.
Some months ago I put in an optima gel battery and box in the right rear passenger seat, left unwired for the time being.
Today was the day to begin the foundation of any DC system - the battery connections. I always do the battery first, and then branch from there.
In another career after school, I spent 10 years in the marine industry and thus the way I do things in the cars is very marine-like. For example, I am a fan of Blue Sea systems products and Ancor wiring connectors. Both are exclusively boat products, but they are WAY tougher than equivalent automotive stuff.
I don't much care how much weight the DC system adds to the car. I always go with a full sized battery and a minimum of 2/0 cables for power. Sure, it adds weight, but who wants to chase ground and power issues because you're trying to save weight.
In this case, I began by routing the old battery cable to the new location by drilling a hole in the bulkhead and putting in a grommet.
I used a Blue Sea battery disconnect for maintenance purposes. It should be noted that this off switch is NOT the emergency disconnect used by first responders. The Devore car already has such a system, with two separate disconnects, one external and one close to the driver. The switch I installed today would be upstream of that, and it's basically a maintenance and storage disconnect.
The Blue Sea stuff is overbuilt and this switch has a 1500 amp cranking rating, which is an order of magnitude more than will be needed.
Next it was time to tackle the ground. People get wrapped around the axle on grounds. In this situation, the ground can be anywhere you want it to be, so long as it's good and solid. I sanded away a convenient location, then welded a bolt directly onto the chassis for a firm, solid ground that I could bolt a battery lug to. It doesn't get much better than this for good grounds.
Finally - and this is super important - once I bolted by negative battery cable down, I immediately painted over the whole assembly with the same undercoater the interior is done in.
Corroded grounds are a MAJOR issue in a multitude of electrical problems that plague many cars. It's important to immediately protect the area from corrosion, so the paint covers everything, while the metal to metal connection is still preserved underneath.
Some of my practices are:
- always use split loom one wiring to prevent chafe
- all heavy gauge wires get hold downs as necessary
- Always use marine grade crimp on lugs with a marine crimper on battery cables.
- Cover the cable almost to the end with electrical tape to prevent corrosion
So now we have the foundation of the battery system. Now onto the accessories!
The undercoater paint in the picture hasn't laid down yet and looks lumpy.
03-17-2017, 03:56 PM
#614
Instructor
"I'd love to build a complete 7.0L motor, I think we have answers for the challenges in the intake and heads and cams that a 7.0L 928 would demand"
+1 A 7.0L motor is sure to take advantage of your ITB intake and the untapped potential of the 928 heads.
I believe a 5.0L motor that makes similar power to a 7.0L turning 6000 rpm would require custom light weight Titanium valves ( https://www.ferrea.com/custom_valves.php ) in order to turn the RPM's that would be required.
I am not talented enough to be able to shift while under high G cornering loads, nice to have torque to power out of corners in a higher gear.
Not sure if the cam drive system would be able to handle the additional loads and torsional resonances that may occur (8000+ rpm is uncharted territory that would not have been in the scope of Porsche engineering).
I always loved this Video (the sound of money ??)
Keep up the good work Carl
To OP awesome project and kudos to your good will to resurrect an icon
+1 A 7.0L motor is sure to take advantage of your ITB intake and the untapped potential of the 928 heads.
I believe a 5.0L motor that makes similar power to a 7.0L turning 6000 rpm would require custom light weight Titanium valves ( https://www.ferrea.com/custom_valves.php ) in order to turn the RPM's that would be required.
I am not talented enough to be able to shift while under high G cornering loads, nice to have torque to power out of corners in a higher gear.
Not sure if the cam drive system would be able to handle the additional loads and torsional resonances that may occur (8000+ rpm is uncharted territory that would not have been in the scope of Porsche engineering).
I always loved this Video (the sound of money ??)
Keep up the good work Carl
To OP awesome project and kudos to your good will to resurrect an icon
Last edited by bertram928; 03-17-2017 at 04:16 PM.
03-17-2017, 04:13 PM
#615
Instructor
"You mentioned boosted engines, and that's enough to get me going. For forced induction, in my opinion one should pay a lot of attention to the cylinder wall thickness and the bore area. Thin walls break once you start making real power, especially with large bore. Large bore also puts more demands on the cylinder head stiffness and fasteners. If one is boosting a 928, I'd stay with 100mm bore or close to that."
Agreed the stock block 5.0 L 928 is ideal for FI:
- free standing cylinder for complete cooling around 360-degree circumference.
- high quality exhaust valves
- thick piston crowns and ring lands.
- Alusil allows more heat to be removed quickly as opposed to steel liners.
- 2.0 rod length to stroke ratio reduces side loading of cylinders, that and long piston skirts keep pistons from rocking aiding rings in keeping tight seal against high cylinder pressures (which are still substantial approaching bottom of stroke)
as opposed to some builders allow bottom of skirt to poke out unsupported from block on long stroke engines, this along with short skirt and higher bore clearance forged pistons results in major piston rocking loss of pressure containment, high oil consumption as well as loss of power and detrimental blow by side effects.
ptuomov
You have great build going, the knowledge gained will benefit the community
Agreed the stock block 5.0 L 928 is ideal for FI:
- free standing cylinder for complete cooling around 360-degree circumference.
- high quality exhaust valves
- thick piston crowns and ring lands.
- Alusil allows more heat to be removed quickly as opposed to steel liners.
- 2.0 rod length to stroke ratio reduces side loading of cylinders, that and long piston skirts keep pistons from rocking aiding rings in keeping tight seal against high cylinder pressures (which are still substantial approaching bottom of stroke)
as opposed to some builders allow bottom of skirt to poke out unsupported from block on long stroke engines, this along with short skirt and higher bore clearance forged pistons results in major piston rocking loss of pressure containment, high oil consumption as well as loss of power and detrimental blow by side effects.
ptuomov
You have great build going, the knowledge gained will benefit the community