View Full Version : Cylinder heads
Govt issue
05-03-2005, 04:59
Has anyone ever put a 6.5 td head on a flow bench. If so do you have the numbers. Also has anyone ever ported one. My thoughts are more volume under the same PSI.
More Power
05-03-2005, 08:20
Just my thoughts.... A diesel operates at a much lower rpm range than a performance gas engine, making it less likely to respond to flow improvements. However, I think it would be beneficial to remove roughness and sharp edges that attract heat - to reduce the heat load that the cooling system has to deal with.
MP
had one on my superflow 600, no you can't have the information it cost me too much. So I know what is possible in stock form and what isn't. Trust me, you guys have along way to go before you run out of cylinder head with the amount of power you are making.
Govt issue
05-03-2005, 11:11
Can you give me a rpm peek? or maybe compare it to a similer gas head. small port 454?
Govt issue
05-03-2005, 11:13
One more thing. Has anyone flowed a 6.6 head?
A friend of mine used to have a 69 Z28 with a blown 350. He had it dynoed before and after having the heads mildly ported, port matched, etc. It made the same HP with 9psi after the head work as it used to at 12psi. Now I understand the differences between gassers and diesels and why the gains would be less on a diesel but.... Porting the heads, port matching, etc. should allow more airflow at lower boost levels. If so wouldn't the differential pressure (turbo backpressure) also be reduced? This should result in less stress on the engine and lower EGT's? How about Extrude Honing the exhaust manifolds too? Sounds like a neat project.... RT
cylinder head flow doesn't help unless the valve is open, kinda the problem with 178 degrees of intake duration.
Govt issue
05-04-2005, 08:20
Maybe we need someone to custom design a cam with more duration. If we go extream with the overlap it may allow higher boost on the stock 22 to 1 compression? Also since we are under boost we don't need to worry about cylinder eff. at low rpms, because of to big of ports.More volume with less Psi under the same rpm curve. Most of the race engines I deal with, heads flow way more than the motor can handle below 4000 rpm. A good example is cabin cruiser motor. not a race motor but a good test bench. 351w xe256 cam. that means all bottom end max power before 4500rpm. also stock intake exhaust. I could pull 3300rpm before the cam. after the cam and ported factory heads. 4000 rpm. then I switched to gt40p heads. 4800rpm.
now the cam and head porting made a huge bottom end improvement. I can pull anything. but the gt40p heads kept the same bottom end power while increasing the top end. more eff, at flowing high volumes of air. maybe like under boost, a more eff head will alow better cylinder filling with the stock 7 psi? Some of the race motors I have delt with too small 302 ford, lost power on bottom end with a e303 cam and only changing to a trick flow r head. Top end was way up. need to much rpm on that small of a cid to become eff. but if it had a turbo? Am I making any sense? I hope I wrote everything that I was saying outloud. I m confused!
I have a set of 99 6.5 heads that were ported . Here are the numbers : </font> Intake Stock : Ported ( Lift & CFM)</font></font> .100 - 64 : 62.4</font></font> .200 - 120 : 122.8</font></font> .300 - 162 : 168.2</font></font> .400 - 176 : 200.3</font></font> .450 - 171 : 208.6</font></font> .500 - Ported 208.6</font></font> Exhaust Stock : Ported ( Lift & CFM )</font></font> .100 - 50: 48.7</font></font> .200 - 93 : 92.1</font></font> .300 - 132 : 130.3</font></font> .400 - 151 : 165.2</font></font> .450 - 155 : 175.6</font></font> .500 - 155 : 183.3</font>
I even had the open and dual plane intakes flowed . </font> Dual Plane Long Runner Stock ( Lift & CFM )</font></font> .100 - 60.3</font></font> .200 - 113.1</font></font> .300 - 152.3</font></font> .400 - 172.2</font></font> .450 - 177.0</font></font> .500 - 178.3</font></font> Open Plenum Short Runner : Long Runner Stock ( Lift & CFM )</font></font> .100 - 60.3 : 62.4</font></font> .200 - 118.2 : 122.2</font></font> .300 - 166.5 : 162.6</font></font> .400 - 187.3 : 180.3</font></font> .450 - 194.6 : 185.6</font></font> .500 - 196.3 : 193.3</font></font> Open Plenum Short Runner : Long Runner Ported ( Lift & CFM )</font></font> .100 - 60.2 : 62.8</font></font> .200 - 117.5 : 122.2</font></font> .300 - 163.4 : 163.4</font></font> .400 - 187.6 : 184.3</font></font> .450 - 195.8 : 191.4</font></font> .500 - 202.1 : 194.8</font>We didn't bother to flow the short runners on the dual plane as the numbers were much lower than the single plane . Initially we thought the dual plane would flow better but that was not the case . The readings were limited to .500 because of the Crane Cams regrind that I have . I'm hoping that the heads and the cam are a good match and will help make more power and keep the EGT's in check with more air flow . Time will tell .
[ 05-07-2005, 08:40 AM: Message edited by: EWC ]
Interesting, and good work..........
Flow benches function at Barometric conditions, much as a naturally aspirated engine does.
Reduce the pressure on the cylinder side, open the valve, and air at atmospheric pressure flows thru - a good indicator contributing to overall volumetric efficiency.
As turbocharging can double or triple (etc) a Diesel engine's natural stock unenhanced volumetric efficiency, depending on Boost pressure, a better indicator would be to compare the same head(s), stock and ported, at equivalent Boosted pressures, on a suitably equipped flow bench.
It's all about how volumetric efficiency effects flow rate, which of course effects power output.
Primary operational difference is Diesel fuel is injected into a cylinder already filled with air - fuel charge is reduced only when you ease up on the go-pedal.
Gasser fuel is trucked in with the incoming air charge, and so may be reduced due to centrifugal force when navigating corners\curves\angles, or rough intake runner surfaces, hot spots, and etc.
If the ports also reduce the air flowrate, the fuel charge is reduced correspondingly.
Boost presents a full charge of air at the intake valve, long before each cylinder intake cycle begins - greater the pressure, faster the cylinder fills per cycle, greater O2 content per unit volume, greater quantity of fuel can be injected, greater the exhaust energy, faster the turbine spins, greater the Boost generated, more fuel can be injected, etc, ad infinitum, within limits, of course.
Repeat as necessary, 1200rpm or 3500rpm.
That's the great secret of Diesel power, folks - not even applicable to gasser technology, and more importantly, vise versa.
In comparison to the Isuzu\DM engine (like comparing grapefruit to cumquat - both citrus, but they ain't the same!) -
the 6.5 is rpm-limited, does not respond well, if at all, to hi-rpm flow enhancements\requirements
the indirect injection scheme does not respond well, if at all, to valve overlap
the turbo removes any requirement for increased valve lift
the stock valve timing counter-acts the high exhaust backpressure in the GM-X series turbos, so necessary to quickly get Boost up off-idle, which improves driveability
the 22.5:1cr limits Boost and fuel increase in constant application
even at 18:1cr, indirect injection limits any massive power increase - combustion chamber is in the pre-cup and that small mickey mouse-eared depression offset to one side of the wrist pin centerline
indirect injection head design creates over-heating problems as power is increased
the 2000psi mechanical rotary distributor injection system is primitive, cannot even begin compare to the 18000psi hi-tech I/T modulated system in the I\DM engine.
This is not a condemnaton of head-work on this engine - even if nothing else, ported and flowed heads give great bragging rights, are a resoundng status cymbal in many groups, and would most certainly not get you the dreaded thumbs-down on SURVIVOR.
Just as with federal income tax, tho - how much return is what gets the grins.
2k bucks per head and extensive cam rework will get you some limited return, even in drag-racing or doing the Can-Am - for a working truck, absolutely none (except for some continued success on SURVIVOR).
IMO, of course.
[ 05-07-2005, 09:58 AM: Message edited by: gmctd ]
the flow information above is incomplete........and useless. I'm very surprised GMCTD and RJ haven't figured out why yet, but it does add more validity to my arguments in the past.
All good points , JD . My first thoughts were to find out if anybody had a cam for the 6.2/6.5 engine . Most of the comments were of the blank stare type until I called Crane Cams . Seems they had one customer , with a boat , that already had one cut . Problem was they couldn't find him to even say if the cam even worked . So for the $180 that it cost me , plus my core , I figured it was worth a shot . I'm the second person to order one and it took maybe 2 weeks to get . No one has posted the specs for the Diesel Depot cam so any comparision can't be made.... just yet . I will be running a Banks kit so I don't have the advantage of chips and other parts . I liked the fact that the cam has more lift and duration while only reducing the base circle by .030 . I'll try the stock pushrods first and see if longer ones will be needed . More air in and then add the fuel ! We'll see how it works out .
[ 05-08-2005, 03:22 PM: Message edited by: EWC ]
Grape , perhaps you will let me know why the information is incomplete and useless .
Govt issue
05-07-2005, 11:04
Thanks for the flow numbers. Were they flowed at 28 inch of vac. or by other means.
Originally posted by EWC:
Grape , perhaps you will let me know why the information is incomplete and useless . govt issue hit it.......no test pressure.
Grape , anything else before I call him ?
rjschoolcraft
05-07-2005, 18:26
Originally posted by grape:
the flow information above is incomplete........and useless. I'm very surprised GMCTD and RJ haven't figured out why yet, but it does add more validity to my arguments in the past. Maybe because I've been gone all day... :rolleyes:
Did you ever figure out why more clearance is needed in the back cylinders...? ;)
It's clear you've been blessed with money to spend on neat machines and have been immersed in the world of racing...something that I longed for as a younger man, but never had the opportunity to do. Consequently, you have access to some information that others don't. What you lack is an understanding of the underlying theory that explains the data you collect. If you would get the chip off of your shoulder, you might learn just how much you don't know and humbly seek out those who have the knowledge that you don't. A guy like me could help you out considerably, but I doubt that you will ever even realize that you need the help. Ignorance truly is bliss.
Grape , my heads were done on a Superflow 600 and finish tested at 28 inches . He could have gone bigger but said that I had good velocity and stopped at that point .
Just as an interesting observation , in the future you might get better responses if you didn't ridicule the efforts of other individuals . You still have not responded to my question about your " blowers are simple for simple people " comment . If you are that up on the 6.2 and know what you can get out of a set of stock heads , why do you need to have 3 different cams ground when you complain about the cost ? Maybe you will respond in a civilized fashion , but your history leads me to expect not .
Govt issue
05-09-2005, 06:31
These heads seem to flow well, but do a search for <stan wess cylinder head flow cfm> and compare it to some of the other small block chevy numbers. it seems that low lift flow isn't as good a a standerd vortech. Im know the boost makes up the difference but a good point. I am glad to see the flow numbers. Now can anyone provide any numbers off a dmax head? The stock 6.5 heads seem to outflow the cummins 2v B series head!
That is the major difference in gasser vs Diesel technology: the turbo does not 'make up for' in Diesel application - it is the key to power.
All attempts to increase flow rate are methods of increasing oxygen input.
An exhaust-driven turbine coupled to an air compressor is the established method for a Diesel - the greater the air pressure, the more the MASS of the oxygen input, the more fuel can be injected.
Your 400cuin engine displaces - pumps - 350cfm at 3000 rpm at Baro.
You can install the heads off the TITANIC on your engine, and it will never pump more than 350cfm at 3000rpm.
Doesn't matter what size the port increase - 350cfm at 3000rpm.
Put a 'blower' on it, at double Baro - 15pisa Baro + 15psig Boost - you've doubled the effective flow rate at 3000rpm.
Add fuel to suit........
[ 05-10-2005, 08:45 AM: Message edited by: gmctd ]
Govt issue
05-10-2005, 04:33
I may be wrong, and that is fine. But 350cfm is at 100% volume eff. The only way you get that at Baro is really eff. heads and cam timing. Just my way of thinking I guess.
DmaxMaverick
05-10-2005, 06:59
Originally posted by Govt issue:
I may be wrong, and that is fine. But 350cfm is at 100% volume eff. The only way you get that at Baro is really eff. heads and cam timing. Just my way of thinking I guess. I don't think you understand what gmctd was saying. No matter what you do to your engine (short of increasing the CID), it will only pump its displacement, regardless of what you do to the air before it enters the cylinder, or after. You can increase/decrease the pressure which will effect the mass of the air (O2 content), but the CFM will still be the same. Improving the efficiency of the flow route, or the use of a compressor device, is a method of increasing the O2 content in that cubic foot of air, but doesn't increase the displacement of the engine.
Govt issue
05-10-2005, 08:18
I understand. But what I don't know is will a non turbo 6.5 pump 350cfm. If it will great, then there is no room for improvement. If it wont then sn't some of the boost used for making up for the lost vol. eff. ? Are the components as good as they can be, head flow, cam ?
There are alot of things I don't know about diesels. I am still learning. But one area I would like someone to explain to me is why ID injection is worse for making power than direct injection. From what people are telling me, this is the limiting factor of the 6.5
It is not a matter of anyone being wrong or right - it is why people are not rushing ported and flowed and stainless tulip-valved 6.5 heads to the market.
Now, if you wanted to cast an economically priced set of direct injection heads, and new pistons with integral combustion chamber, maybe a forged steel crank, and how about a new block with 6 evenly-spaced head-bolts per cylinder - why, that'd be another story, indeed.
Not meant to discourage, just to inform.
Ease over into the Members Area - various pic's of 6.5 heads are in several areas, there, give you an idea of the I\I head configuration, and the Ricardo Comet IV combustion chamber setup.
Might be an eye-opener for ya.
Not sure where the 350 CFM comes from as the Donaldson Exhaust Catalog has some specs
</font> Navistar 6.9L 3000 RPM 330 CFM</font></font> Navistar 7.3L 3000 RPM 349 CFM</font></font> Cummins 4B3.9 2500 RPM 150 CFM</font></font> Cummins 4BTA3.9 2500 RPM 298 CFM</font> There is a formula as well
</font> ( CID x RPM / 3456 ) x VE = CFM</font></font></font> VE = N/A Diesel = .90</font> VE = N/A Diesel Turbo = 1.35</font></font>
I don't think the statements about CFM flow are correct as the CID is trying to be equated to CFM . Air does have a weight and as such can be influenced by port design and velocity . If the intake valve lift is drastically reduced , thus effecting CFM , will the CID or CFM be reduced ?
I also think boost is a resistance to flow and if you reduce the resistance , at the same boost , you will flow more air . The resistance can be the valve design , valve being closed or the ports themselves . Reduce the resistance and the volumetric efficiency will increase .
Most of the comments about boost and flow are assumed to be when the engine is making full power or boost . What about the transition from vacuum to boost ? Yes I said vacuum . If there were no pressure differential when the intake valve was opened , there would be no air flow into the engine . I'm not talking about the upper RPM's , when under boost , but more so when the engine is operating at lower RPM's .
And what about the N/A engines ? There is obviously a lack of boost and yet they still run . Opening up the exhaust has an effect on these engines , porting is just a major effort to improve the efficiency of the engine .
Just some thoughts .
Dam', EWC - you ain't much better'n them hard-nosed teachers I had back in school, allus makin' me re-do it so's to get it right! tongue.gif
And, you know numbers just make my head hurt!
So, simplest answer is - yes, and, no
More, later - I hope........ ;)
Later
So.........
My official position has always been -
Port matching will give better results than polishing, but if you got the time, shine 'em up!
Any restriction to flow can be due to small ports or valves or low valve lift, but, seemingly, not in this max 3500rpm case.
Restriction can also be type of air filter used, dirty air filter, type of intake ducting, etc
Piston at TDC displaces cylinder volume - as piston drops, cylinder volume increases to max volume just before BDC, and does not change within a small arc across BDC
Baro rushes in where fuel is soon to spread, as it were.
Or, is it - fuel rushes in, where.....ummm, never mind - wrong maxim.
That's how N\A Diesel's run without vacuum, fapp.
Prove it, you say?
Remembering the air filter is a restriction, tho slight (hopefully) -
(Numbers rounded off, of course, except CDR calibration)
CDR is calibrated to close at 4-6" H2O at 2000rpm
27" H20 is 1psi
1psi is 2"hg
Baro is 30"hg, 15psia
Vacuum at 30"hg is 0psia
2"hg vacuum would be -1psia, or 14psia in manifold vs 15psia other side of air filter
CDR is calibrated to close at 4-6" H2O at 2000rpm
Gassers idle at ~20"hg manifold vacuum - 'nother words, 5psia in the manifold below the throttle-plate(s), 15psia other side of the air filter, above the t-p(s), for 10psia differential..
Open the throttle-plate(s), that differential begins to equalize, but seldom does equalize, even with rpm increase.
That, and valve-shrouding due to combustion chamber size and shape, is why gasser VE is much lower than Diesel, even at WOT
That's why n\a gassers can be tuned for max power across very limited rpm range - tuned ports, tuned pipes (headers) increase VE at specific upper rpm range
Diesel heads are essentially flat across cylinder surface, so valve shrouding is effectively zero, fapp, equivalent to that of a hemi gasser, which increases VE
Increased valve-lift and valve shape can decrease shrouding-effect in gasser heads, increasing VE
Dirty - restrictive - air filter will reduce volume of air pumped - displaced - reducing volumetric efficiency.
EGR mounted across intake plenum reduces VE - 6.9, 7.3, 6.2 were equipped with such
Excess heat in intake manifold reduces VE - exhaust path(s) to EGR valve
Type 'C' vs type 'J' engine would be good example of that, comparing HP rating
Cylinder head porting, valves, and piston crown configuration can reduce VE
6.2\6.5 Ricardo Comet IV cc increased VE over 6.9\7.3 n\a engines
Air filter type, housing, and ducting used back then (1980's) reduced VE
RPM can reduce VE
We got better, since 1980's....much better.
When any physical dimension - displacement, rpm, etc - prevents further flowrate increase, increasing input pressure will result in increased flow.
When the flow rate of the compressor is greater than the flowrate the engine pumps, result is Boost
And Boost, as we all know, increases effective flow rate by squeezing a large box of air into a small box, then squeesing many of those small boxes into same volume as that original large box.
If a 1cuft box of air weighs 1lb and will burn X quantity of fuel, a 1cuft box of air with two 1lb\cuft boxes squeezed inside can burn 2X quantity of fuel
Next - how I arrived at 400cuin engine displacing 347cfm at 3000rpm....or, was that at 3500rpm?
I hate numbers - numbers been very very bad to me............... :confused:
;)
[ 05-15-2005, 08:03 AM: Message edited by: gmctd ]
Sorry for the headache , I'll send you some aspirin !
My thoughts were that anything lower than 14.7 psi was a vacuum , but that's obviously not right . It would be interesting to put a vacuum guage right at the valve to see what range of readings there are as no one has reported any readings so who can say if there is a vacuum or not ? Definately lower than 14.7 psi , but by how much ?
One of the reasons that I had to let my heads get ported was that he didn't seem to care if the heads were from a diesel or a gas engine . Basically , air flow is air flow . The turbo is one way to make a diesel run well . It is a device to force air into the engine . If you can reduce the resistance , the turbo will move more air into the engine . This may also yield a cooler charge of air as the turbo will not have to work as hard to move the same amount of air . Back in the 80's Olds was trying to drum up support for the 350 diesel and had a hot rod 350 that had an intake manifold that was similar to the old 413/426 wedge that had the two carbs out by the valve covers . This was obviously tuned for a specific RPM , but the point is no turbo and by design you could get more air into the engine if the system was correctly balanced . Somewhere there is a number for the velocity of the incoming air that will fill the cylinders completely . The CFM is not as important as the velocity as this can be changed and ports can be reshaped . My heads are not that big , but he said I had good velocity and stopped there . Smaller ports also do not mean a lower flow or restriction if the ports are correctly designed . Just because we only run to 3500 RPM's does not mean that we can't improve on the air flow . The air doesn't know if the engine is gas or diesel , or care , it just responds to changes in shape , temperature , pressure , etc like other engines .
I have a piston from a 7.3L N/A engine and it has something very , very close to the Ricardo Comet chamber and the heads that I have seen , I thought they were 6.2L heads when in fact they were 7.3 L heads . If you take a 6.9L piston , .020 over a 6.2L bore , and offset grind the 6.2L crank from 2.400 down to 2.200 ( big block Chevy ) you would have a 6.9L Chevy . The cool thing about this is the 6.9L piston has the wrist pin located .180 higher up so you would only need rods . Just a thought .
As you know, vacuum is a term used for measurement of pressure less than Barometric pressure.
The CDR calibration gives you the answer - any intake vacuum is usually less than 6"H2O - about 1/4rth psi = 0.5"hg - and that can increase in event of dirty - restricted - air filter.
I'd venture less than 27"H2O - 2"hg overall - less than 1psia n\a up to 3500rpm.
The greater the intake vacuum in a DIesel, the greater the inefficiency.
The greater the intake pressure in a Diesel, the greater the efficiency.
Be easy to check with a n\a van and a gage.
Turbo CDR is same - 4-6"H2O at 2000rpm.
Main difference where port polishing works in Diesel and gas is - gasser fuel charge is carried in with incoming air charge, requiring smooth, smoothly transitioned passages to prevent centrifugal separation of fuel and air.
That problem does not exist, where fuel charge is injected into a cylinder already full of air.
Ram air and tuning has little effect at low rpm, as has polishing ports.
My point is - as those techniques show little gain in a Diesel engine at low rpm, folks do not eagerly rush forward with orders when anyone mentions porting, polishing, and flowed 6.5 heads.
Do a search, and check it out - that mention is usually from someone new to Diesels, not yet familiar with any Diesel, or the differences and variations available.
A chip or re-flash, on the other hand, offers tremendous, seat-of-the-pants performance increase, for considerably less time and money.
Compare that to the time and effort required in simply removing and replacing the heads.
Not intended as argument, EWC - just alternate information
[ 05-16-2005, 07:42 AM: Message edited by: gmctd ]
dieseldummy
05-15-2005, 18:03
If there were nothing to gain from head porting a diesel then I don't think that Piers and the Haisleys would be making out so well with porting the 5.9 cummins...
Cannot even imagine anyone foolish enough to argue with that statement, dd......... :cool:
But, let's stay focused, here -
GM 6.5nGMo6.5tGM 6.5cGMu6.5mGMm6.5iGMn6.5sGM 6.5
Etc, et al, ad infinitum..........
[ 05-16-2005, 03:18 AM: Message edited by: gmctd ]
This thread has got me thinking about building an experimental engine.
I have a 6.5 block that was given to me. It is crack free but does have a few spun bearings and needs line bored. So I was thinking of making new steel main caps and a girdle that will bolt to the oil pan rails and then the oil pan will bolt to the girdle. I have a machine shop here at home so this will not cost much except my time.
I would also like to cast two aluminum heads and make the engine direct injection. I will need different injectors and also some direct injection pistons with the bowl in the top. Does anyone know of any direct injection pistons that are similar in size to a 6.5 piston? How do guys think this will work?
I think you could do it - iirc, 7.3 used a long injector down thru the intake side.
Also used tha same inj pump, so the inj pipes would be available, with slight modification.
Would make easy job of removing valve covers, with inj pipes along intake side.
May have some difficulty with the odd head-bolt pattern, particularly the wide spacing across the injector\glow plug area.
As you know, cast aluminum is not as rigid as cast-iron.
Be nice, if that area could be used for larger exhaust port, but you'd need to retain the oem valve configuration to fit the camshaft and intake manifold.
Extra thickness there could compensate for wide spacing.
That is, if you intended it to be a field-installable upgrade, using oem parts.
The bore on a 6.5 is 4.057 and the bore on a power stroke is 4.11 so I would have to bore the 6.5 .050 over to accept powerstroke pistons. I am not sure of the location of the wristpin. Does anyone know of any direct injection motors that would have pistons that are closer in size to a 6.5?
Also, does anyone have any old powerstroke pistons that I could experiment with?
Govt issue
05-18-2005, 05:57
If you want a junk 7.3 piston I will check with my machine shop today, I need to check on a motor in one of our restos. Let me Know.
DmaxMaverick
05-18-2005, 09:21
Pistons?? I'm surprised no one brought this up. The Duramax bore is 4.06". I don't know if they are available in overbore, but I don't think the Duramax block can be bored due to induction hardened cylinders. If they can be sleeved, perhaps the same sleeve can be used in a 6.5L.
Govt issue,
That would be great if you could get me a powerstroke piston with the bowl in the top. I would be more than happy to pay the shipping to me.
DmaxMaverick,
The duramax also sounds like an excellent choice. The block I have is not worn very much at all. Probably a little honing and the d max piston would go right in. You don't happen to have one laying around do you? :D
DmaxMaverick
05-19-2005, 02:41
Laying around??
Got 8 of 'em. Unfortunately, they're kinda' busy right now. Actually, I've never seen them, but they must be there. I don't know what they would cost, but I bet they're spendy. Probably not a real big deal if a person was already messing with having heads cast.
Realistically, it would be cheaper to drop in a Duramax engine from a wreck than trying to mod a 6.5 only to have the bottom end drop out the first time you mashed the pedal.
I'd like to see someone spend their efforts on converting a Duramax to mechanical injection. That would be bulletproof. I think it would be easier (and cheaper) than converting a 6.5 to DI.
I know what you are saying about just dropping in a duramax but that is a little out of my budget. I really wouldn't have much in casting a new set of heads. The only real cost would be for valve guides and valve seats. I would try to use the old 6.5 valves and springs. The castings would be free except for my time. As for the bottom end holding up, I think a girdle and a billet steel crankshaft would take care of this. I have been wanting to make a billet crankshaft anyways because I have some tractor pullers that want one for their tractors but just need to see a finished product before they will let me make them one.
I guess the powerstroke pistons would be the way to go. I could probably find some good used ones and maybe even use the powerstroke rods. I could make the journals on the crank the same size as a powerstroke and make the stroke so that piston comes up flush with the block.
To Jim P:
For your direct injection engine idea. See if you can make a nozzle tip that will fit. VW TDI 4 cyl diesel use this way to direct fire there engine.
The injector is completely outside of the head and a nozzle tip extends into the head and combustion chamber. The nozzzle tip will extend into the combustion chamber through the already there idi hole. The idi hole can be machined to fit any feasible size of nozzle that you can put to it. You can retain the same injectors and injector location. May be the most that you would have to to is make some threaded sleeves for the injectors that thread onto the nozzles. I can see this idea making a space problem though, but you will not have to remake the heads or reengineer the direct fire from another existing design.
P.S. Don't listen to anyone who says that you should not go ahead with this experimental 6.5L DI engine.
ogrice,
You might be on to something. I never really thought about it.
I suppose a guy could remove the precups and machine a solid plug to fill the hole. Then machine a solid threaded plug to fill the injector hole(like you said). Then just bore down through both of these to accept the new direct injection injector. Some Oliver tractors and somw John deeres had the small pencil injectors. The injector would going in at an angle but that is the way John deeres have been for years. Like you say the drawback may be a clearance problem under the turbo. I have a set of heads out in the shop. I will check this out a little closer tomorrow.
Thanks for the words of encouragement.
I just went out and looked at the heads. Even if you bored the new injector hole in at an angle, the injector tip would still not be in the center of the piston. Most direct injection motors have the injector in the center.
I wonder if a guy could bore a new hole right through the water jackets and then press in a brass injector well just like an International dt466.
Something to think about.
If you are worried about getting the flame to travel from the center of the combustion chamber then I can see the dilemna. However, many engines both gas and diesel(including the 6.5l) induce ignition in the combustion chamber sometimes far away from the center of the piston. With the properly machined dished top in the piston the difference should be negligible. You could add some new things to the dish top that other engines don't have like a swirl or wedge design. I don't see this as a setback, I see this as an opportunity to suceed with more variables to achieve sucess. Think outside the box and take in account all angles.
What about taking the precup out ? Leave just enough to cover the gasket . Almost DI .
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