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Thread: 350 diesel: Pencil Vs. Poppet I.P.

  1. #1
    Join Date
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    Default 350 diesel: Pencil Vs. Poppet I.P.

    I am beginning to plan for my next diesel conversion. It will be a square body GM wagon from the 80s (preferably a Custom Cruiser or Caprice Estate), and I am in possession of a Goodwrench 350 Diesel DX block engine with only 38,000 miles on it. The car it was installed into was badly rear-ended, and as a result it was totaled. I got to hear it run before I pulled it, and I got it for $75. I know that there are people who hate this engine, but I am not one of them. I drove one for 5 years starting in my Sophomore year of High School; it was my grandfather's car, and he gave it to me with a bad transmission and said if I fixed it, the car was mine. It was a 1980 Olds 98 with a POS THM-200C transmission. I replaced it with a THM-350C and drove this car 80,000 miles with that engine. The engine was a Goodwrench engine (it went in at only 18,000 miles). The car had rolled the odometer twice when I got it (nearly 200,000 miles on the engine, despite the transmission being replaced 4 times before I got it) and I put another 80,000 on it, and I was a leadfooted teenager that whooped on it every day. I got a kick out of getting over a week out of $10.00 of fuel, despite driving it like the "General Lee" and single-handedly controlling the mosquito population in Delaware County PA (where I grew up). I am saving my other 6.2L diesel for my F-150 if and when my 300 six gives up. The Olds diesel will drop right in to anything that has a 307 Olds engine with virtually no fuss, and this is another reason I am intent on using this engine. So if you want to drop negative comments about the engine instead of answering my question, I would politely ask that you refrain from discussing this topic. I will give this engine a full once over and put it back together with quality parts and ARP bolts if it is in suitably decent condition. My question is for those of you with more knowledge than I about the DB-2 injection pump, particularly as it pertains to the 350 Olds diesel in pencil and poppet injector forms. (If you think my I.P. idea is stupid and leave a negative but constructive comment about it that is different, because I am looking for that particular feedback).

    As we 350 diesel fans have heard many times before, the pencil engines tend to be peppier. Many have ascribed that to the I.P. not necessarily the injector. However, the poppet engines use a mechanical light load pump, and the pencil engines use speed advance. The two pumps are known to not be interchangeable. Part of that I believe is the pressure equalizer circuit in the hydraulic head of the poppet I.P. What if the hydraulic head for a poppet pump were transplanted into the body of a speed advance pencil style pump? This would provide the correct hydraulic circuitry for the poppet injectors, while affording the superior performance of the pencil I.P. and the better performing speed advance setup. I came to this idea after reading my GM Product Service Training book "The 5.7 Liter Diesel Engine" yet again. I spent a great deal of time reading and re-reading the section on the DB2 pump, and suddenly the idea was there. What do you guys think?
    1993 Suburban 2wd 6.2L Diesel Conversion "Andromeda":
    3.73:1 gears, THM 700-R4 transmission, and
    J-code 6.2L diesel from a 1984 C2500 Suburban

    1996 2wd to 4wd converted Ford F-150 300ci Inline 6 "The Argo" 336,000 miles and climbing

    1992 Caprice Wagon 5.0L V8 "Enterprise-D"

    "Ah ha ha ha! I swear! Tractors is so dumb!" - Mater

    "The Argo? That ridiculous pile of scrap metal!"

  2. #2
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    Default

    I,ve no idea about mix and matching IP parts,.
    My experiences,.
    i got better fuel mileage from low pressure poppet motors,.
    don't put a pencil injector pump on a poppet motor,. it takes out the head gaskets quick sounds bad,. ,.
    Put head studs in and the little motors are good to go for a long time,.
    last one i did i added roller rockers,. 2 large remote oil filters,.and a toilet roll type bypass filter,.and a set of headers,.
    they'll take more timing than the factory says and are noisier but happier with it,.,
    check youtube for guys with turbo's on them,.
    My 81 chev caprice got a best of 41mpg running interstate from east coast to west coast,.and with the advanced timing and a manual glow plug controller,. would start at minus who knows what temp,.use bosch duraterms, they won't swell up and pop,.
    after you're done playing with the diesel,. you can use it for an anchor and add a 455 olds for a fun only ride,.

    Clean oil is the key,. olds motors use an aluminum non adjustable rocker arm pedestal, dirty oil wears them fast, .keep a decent timing chain in it, as they stretch fast and the pump timing gets behind,. they slobber and then crap up the oil twice as fast, not to mention poor starts and less than optimimum mileage,.
    200R4/700R4 work well BUT, you should have 3:23's or 3:42's, then the 350 seems quite peppy compared to trying to pull 2:21's,.

    I,m keeping an eye out for an el camino diesel for another daily driver,.
    My all time favourite was an 81 burgundy with burgundy interior fleetwood brougham with an indash 8track CB combination,had the radio peeaked and tweaked etc,. i was the 'cadillac kid' of course,..i put slotted polished aluminum mags with G60-15 tires on it,. looked cool,. back in the day,.

    Nick
    Old 5.7 diesel junkie,.
    1999 chev suburban C2500
    300,000 mi

  3. #3
    Join Date
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    Default

    I can't answer your IP question, but I would like to add that my very first diesel was a 5.7L that I transplanted into a '77 Blazer 2WD. I was a college kid that needed cheap transportation and good fuel economy, and I couldn't stand driving small vehicles. I picked up the complete running Olds drivetrain from a salvage yard for just a few hundred bucks, and dropped the Olds motor and tranny into the Blazer.

    Immediately upon first startup, I found blown headgaskets. I replaced them, and drove it for another 3 years before it blew the gaskets again. I then pulled the 5.7L and replaced it with a 6.2L.

    If I knew then what I know now, I would have properly fixed the engine with studs and other upgrades. I ended up scrapping that motor, and it makes me sad that I sent another 5.7L to the grave!!

    That Blazer consistently gave me 24 mpg.
    1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter

  4. #4
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    I owned several of the Olds diesels back in the day.

    We had 2 cutlass's with the 260 diesel, one of which I transplanted a 350 diesel into. (260 V8 not the V6)

    Swapped one into a Shorty 4x4 pickup. Was no ball of fire but got great MPG.

    The DX engine was the best one that was produced.

    27 MPG Hwy was not tough to get if the engine was in good shape and the injectors and such were up to snuff.

    I would concentrate more on having the stock setup in top condition rather than making a wild cat out of it.

    The DX engine had the roller cam installed as well as some other improvements.

    Sadly, by the time the DX came out, the buying public was fed up with the poor reputation of the Olds diesel and would not buy them.

    If cared for properly they were a great little engine.

    They would knock down some super mileage for sure.

    Chevy even offered the 350 in a light duty 1/2 ton pickup.

    The major issues were head gaskets and cracked heads.

    A few broke cranks, but the blocks were pretty good without much trouble.

    It was a great idea from a factory option point of view, as these would fit easily into most GM rigs with minimal parts swapping.

    Olds, Buick, Pontiac, Cadillac, Chevy all had this engine available.

    Just as GM did with the 6.2/6.5 there were corners cut and shortcuts taken and the result was a bad reputation due to failures..

    The folks that understood these engines and took care of them had pretty good service.

    There are still a few running around here.

    Have fun with your vintage diesel.

    Missy
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  5. #5
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    Default

    5.7 Conversion discussion moved to Diesel Conversions
    1982 C10 SCSWB 6.5TD, mods too extensive to list. (13.69 1/4 mile @94.6 MPH) RACE TRUCK
    1982 C10 SCSWB 6.2NA, 2.73 700
    1986 C10 SCLWB 6.2TD 3.73 700
    1989 V20 SUB 6.2NA, 3.73 400
    1994 G20 VAN 6.5NA, 3.42 60E
    1994 K20LD ECSWB 6.5TD, 3.42 80E
    1995 K20 SUB 6.5TD, Wrecked, ran into by stupid teen.
    1995 C3500HD DRW 6.5TD, 12' Flatbed 5.13 80E
    1995 C3500HD DRW 6.5TD, 18' Rollback Wrecker 4.63 80E
    1994 C20HD ECLWB 6.5TD 3.73 80E Wifes Truck.
    1995 C20LD ECSWB 6.5TD 3.73 80E
    1995 K20LD SCLWB 6.5TD 3.73 80E
    1996 K30 DRW 6.5TD 4.10 80E
    1997 C10 Tahoe 2Door 2WD 5.7L to 6.5 Conversion Underway

  6. #6
    Join Date
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    Default

    Thank you all for the advice. Outside of Olds-Diesel.com, I rarely have had a discussion about this engine without a double butt-load of negative comments, so that's why wrote my disclaimer. I worked at an Olds dealership in the 1990s and there was a fella there who had three diesels. He bought two as trade ins, and fixed them up and got them running strong. The third was an Olds Custom Cruiser that he pulled some strings to buy brand new in 1990 without an engine from the factory. He put a fresh Goodwrench engine in this car after upgrading it with all ARP hardware, an aftermarket oil pump driveshaft, Victor Reinz head gaskets (.010" thicher .030" overbore), and a RAYCOR water separator, and he is still rocking that car to this day. He takes it to Arizona and Florida several times a year. I now has 338,000 miles on it (as of last Memorial day weekend, when I last saw him). It looks almost as good as new, with the exception of the header panel which is sandblasted, but he will be getting that and a few minor dents and scratches painted this fall. He also has another 5.7L Goodwrench engine sitting on a crate in his garage, incase this one ever gives up. so much for it being a "pile of crap". Thanks for the input. I probably will leave the I/P alone except for reconditioning it. I also think I'll do 3.23 gears. That was the trailer towing axle ratio for the wagons IIRC.
    1993 Suburban 2wd 6.2L Diesel Conversion "Andromeda":
    3.73:1 gears, THM 700-R4 transmission, and
    J-code 6.2L diesel from a 1984 C2500 Suburban

    1996 2wd to 4wd converted Ford F-150 300ci Inline 6 "The Argo" 336,000 miles and climbing

    1992 Caprice Wagon 5.0L V8 "Enterprise-D"

    "Ah ha ha ha! I swear! Tractors is so dumb!" - Mater

    "The Argo? That ridiculous pile of scrap metal!"

  7. #7
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    Southern Delaware
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    Default

    Quote Originally Posted by john8662 View Post
    5.7 Conversion discussion moved to Diesel Conversions
    Thanks. I wasn't sure where to put this one, since there obviously is no 5.7L Diesel Forum.
    1993 Suburban 2wd 6.2L Diesel Conversion "Andromeda":
    3.73:1 gears, THM 700-R4 transmission, and
    J-code 6.2L diesel from a 1984 C2500 Suburban

    1996 2wd to 4wd converted Ford F-150 300ci Inline 6 "The Argo" 336,000 miles and climbing

    1992 Caprice Wagon 5.0L V8 "Enterprise-D"

    "Ah ha ha ha! I swear! Tractors is so dumb!" - Mater

    "The Argo? That ridiculous pile of scrap metal!"

  8. #8
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    Southern Delaware
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    Quote Originally Posted by phantom 309 View Post
    after you're done playing with the diesel,. you can use it for an anchor and add a 455 olds for a fun only ride,.
    Actually, I want to find an 80-84 Ninety Eight Regency Coupe and put a 455 in that as the fun car. All trimmed out with cold A/C, power everything, overdrive transmission, a nice stereo (not a blinged out thumper, but something that will clearly play classical, rock, country, doo-wop/motown, etc. loud enough for windows down highway cruising). That will be great!

    I'll have a diesel 'Burb, a diesel wagon, a diesel F-150, a 455 powered 98 Regency, and a tri-carb 300 straight six powered 49 Mercury. I love my straight six too much to let it go, so I'll have to overhaul it, put a lumpy cam in it, a tri-carb setup on it, and drop it in a suede 49 Merc with a 3 on the tree, no power anything, lakes pipes, and chrome reverse wheels with moon caps wide whitewalls. A boy can dream (at least about the last two)...
    Last edited by argo; 06-14-2011 at 09:50.
    1993 Suburban 2wd 6.2L Diesel Conversion "Andromeda":
    3.73:1 gears, THM 700-R4 transmission, and
    J-code 6.2L diesel from a 1984 C2500 Suburban

    1996 2wd to 4wd converted Ford F-150 300ci Inline 6 "The Argo" 336,000 miles and climbing

    1992 Caprice Wagon 5.0L V8 "Enterprise-D"

    "Ah ha ha ha! I swear! Tractors is so dumb!" - Mater

    "The Argo? That ridiculous pile of scrap metal!"

  9. #9
    Join Date
    Aug 2006
    Location
    Edmonton Alberta, Canada
    Posts
    52

    Default 6.2 to 350DX swap?

    Hey guys & girls, thought I would post this in this thread as well just in case, I was hoping some of you here may have some experience and recomendations on this......

    So I had been planning on dropping my spare Humvee 6.2 into my truck (86 GMC 3/4Ton 4x4 6.2L+th400+4:10's+AC all stock) when my orginal 6.2 siezed up. The problem is that when i dis-assembled the Humvee 6.2 to put new gaskets throughout I found spun rod bearings in #1-2 and a badly damaged crank. I just don't want to spend the money this year on a new build up.

    So I have 79 2wd 1/2Ton that is very rusty with a bad th400 but a really strong Goodwrench 350DX unfortunately the milage is unknown but speedo says about 150k+ miles just have no idea when the engine was replaced during that 150k so the engine has something less than that, 75-100-125 who knows. it starts easy, runs great, gets great fuel milage.

    I see the th400 bellhousings are different on the two trucks and the position of the engine mounts is different, and of course 6.2L truck is a 4x4 while the 5.7L truck is 2wd. It seems the biggest challenge is that bellhousing because of the position of the 5.7 vac pump and I'm not sure about bolt patterns matching up? (5.7 has the dip in the top of the bellhousing, th400 has the peak at the top).

    Is there anyway to put the 5.7L into the 6.2L 4x4 truck with the chev th400 bellhousing? Has anyone done this before? Is there anything else to be aware of with this conversion?

    This would be a short term temp setup until I rebuild the 6.2L next year sometime.

    Also what about fitting a 6.5 TD into this 86 6.2L 4x4 w/AC? easy or hard?

    Anything you can tell me would be great, thanks.
    Thomas Taylor

  10. #10
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    Apr 2001
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    CA
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    13,573

    Arrow

    The 350/5.7L bell housing pattern is BOP (Buick/Olds/Pontiac), while the 6.2's are standard Chevy. You'll need an adapter, but they are common, available and inexpensive.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  11. #11
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    Aug 2006
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    Edmonton Alberta, Canada
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    Default bellhousing

    Ok thanks, that's great to know, can you provide any leads on a supplier? And is the 350 vac pump not a problem then, does it not get in the way of the chevy bellhousing?

  12. #12
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    Aug 2006
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    Edmonton Alberta, Canada
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    Default suppliers!

    Quote Originally Posted by tomtaylor View Post
    Ok thanks, that's great to know, can you provide any leads on a supplier? And is the 350 vac pump not a problem then, does it not get in the way of the chevy bellhousing?
    Thanks again, but I found suppliers online today, Jegs & Summit Racing have all kinds of adapters. I can get the chevy th400-to-Olds350DX adapter for about $100-$125 after shipping costs!

  13. #13
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    Apr 2001
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    CA
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    Arrow

    Yeah, the BOP/Chevy adapters are very common. You may try Ebay for something less expensive, but that's about as complicated as it gets.

    I'm not aware of any issues with the vac pump. If you have one, it'll be the first I've heard of.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  14. #14
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    Illinois, USA
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    Default tomtaylor: 6.2 to 350dx swap

    Thomas:

    Your project sounds very interesting to me. I have a similar project in mind. I was curious if you started on this project and/or finished, and what kind of results you've seen. What type of injectors does your 350DX have? I'd be really interested in how you made out. I have 2 Goodwrench engines; one with pencil injectors, the other with poppet injectors. I would like to put one in a C20 2wd. Any information appreciated.

    [Not sure if I'm posting this right--new to the site.]

    It's good to hear you can get good mpg with 3 speed transmissions. I wonder what kind of rear-end ratios you're dealing with.

    I have a 700-R4 [and adapter plate] and a TH350C with a diesel low-stall TC, that I could use.
    Last edited by Titania305; 02-08-2012 at 23:38. Reason: add information

  15. #15
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    Quote Originally Posted by Titania305 View Post
    Thomas:

    Your project sounds very interesting to me. I have a similar project in mind. I was curious if you started on this project and/or finished, and what kind of results you've seen. What type of injectors does your 350DX have? I'd be really interested in how you made out. I have 2 Goodwrench engines; one with pencil injectors, the other with poppet injectors. I would like to put one in a C20 2wd. Any information appreciated.

    [Not sure if I'm posting this right--new to the site.]

    It's good to hear you can get good mpg with 3 speed transmissions. I wonder what kind of rear-end ratios you're dealing with.

    I have a 700-R4 [and adapter plate] and a TH350C with a diesel low-stall TC, that I could use.
    I never did actually purchase that 350dx motor at the time I posted about as the owner was difficult to get in touch with. the only difficulty would have been sourcing the adapter plate but I found them online easily for about $80-$100 and I could just plug and play that 350 with my truck with no more difficulty than putting the 6.2 back in.

    I probably could have even used the 6.2 glow controller but the 350 came with it's own system anyway. I am not sure now which injectors that motor had so I can't comment on that now.

    Did you get around to doing a swap?

  16. #16
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    Default

    Quote Originally Posted by Titania305 View Post
    Thomas:

    It's good to hear you can get good mpg with 3 speed transmissions. I wonder what kind of rear-end ratios you're dealing with.

    I have a 700-R4 [and adapter plate] and a TH350C with a diesel low-stall TC, that I could use.
    Also about the gears my truck is a 3/4 T 4x4 with 4:10 gears but I am a very sane driver with this vehicle I try to keep all my high way driving at 50-55/mph or 80-90/kph

    I calculated 10+ mpg with a 14000lb total vehicle load (truck and trailer) on a 600 mile trip (1000 km) trough the rocky mountains of BC in January and a lot of that distance in 4 wheel drive

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