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6.2 questions. Diesel owners me pick your brain good

tRustyK5 said:
Stomis, the HPCA stands for Housing pressure cold advance or something like that. It slightly advances the pump timing and bumps the idle speed by about 100 rpm. On the IP there will be one spade for the fuel cut-off, and then another couple of spade connectors. The other couple are for the HPCA. I currently run mine with a manual switch, my temp sensor is MIA.

I ran a 12 1/4" Hayes diesel puller clutch behind my 6.2. I liked it, although even being a diaphram style and with hydro pedals it was a little stiff. Really good clamp pressure though. I don't think it's physically possible to run a clutch larger than that using a normal bellhousing.

You'll either need to go to hydro-boost and all manual HVAC stuff, or run a vacuum pump of some sort. The majority of 6.2's you're gonna find out there will have a vac pump mounted where the dist would be on a gas engine. That vac pump is really only for stuff like Cruise, and HVAC...not meant for vac boosted brakes. If you find a 6.2 from a low optioned manual tranny truck it'll have a block off slug back there. Much cleaner, and better firewall clearance. My 6.2 from my Jimmy has that. It's only purpose is a gear that meshes with the cam so it can drive the oil pump.

Rene
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Alright I was curious as to whether the vac pump was up to the duties of the brakes but I guess not then. I'll switch the brakes to hydro along the process and keep the vac pump for the HVAC.

As far as the cold advance I'll be sure to hook that up.
 
damn, you just jump in with both feet i see. sounds like a great project. good luck with it
 
sorry not now.. sold some and scraped some. what i have left i know nothing about
 
The mechanical lift pump is fine to run. I'm running an electric because the stock 6.5 turbo setup uses the fuelpump opening as the oil drain for the turbo. The nice thing about an electric pump is it will prime the fuel filters after you changed them. No need to crank the motor to do that.

I would do hydroboost brakes, they are waaaaaay better then vacuum boosted.

As for the timing gears I'm not sure. I'm checking some of the usual vendors and I'm not seeing them :dunno: . I can't explain why.
 
KirsL said:
The mechanical lift pump is fine to run. I'm running an electric because the stock 6.5 turbo setup uses the fuelpump opening as the oil drain for the turbo. The nice thing about an electric pump is it will prime the fuel filters after you changed them. No need to crank the motor to do that.

I would do hydroboost brakes, they are waaaaaay better then vacuum boosted.

As for the timing gears I'm not sure. I'm checking some of the usual vendors and I'm not seeing them :dunno: . I can't explain why.
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I saw a couple articles that said they stopped manufacturing them...

I wanted to pick a set up just to eliminate one more wearing item in the motor. Guess I'll have to find one use...
 
Its seems that way. Might get lucky making some calls to the places that used to have them. Worth a shot at least.
 
Kennedy Diesel had a few sets of the Pete Jackson gear drives left as of a few weeks ago if you have to have one. However, my experience with floating dual idler gear drives (most from Pete Jackson) in race engines is less than spectacular. They claim more consistant timing and they do a good job to begin with, but they wear so fast that they become way more erratic than a chain in a short period of time. I'll just say that no serious race engine builders use them. Modern High HP engine builders use belt drives, or fixed idler gear drives. In dirt track racing, a good quality chain (like Cloyes Hex-a-just for example) is preffered over dual idler gear drives. I sold an '84 K10 with 339K on clock on the original 6.2 a little over a year ago and still ran good. The IP was replaced by the PO at 220K, but he didn't do the timing chain. I've had (7) 6.2/6.5 trucks and currently have (2) and I've never had a problem stemming from the chain. I'd spend your money elsewhere, because the timing chains do a good job. If the gear drives for 6.2's were so great, and considered a neccessity, there would be several companies selling them. JMO
 
I disagree if you can find the gear set run it, No heavy duty Diesel runs a timing chain the cams are ALWAYS gear driven . the timing chain is the one thing I do not like about the 6.2.

The timing issues you speak about on a gas motor are not as prevalent in a 6.2 the engine speeds are much lower as is the engine acceleration its apples to orages comparison

I've not heard ANY complaints about using the gear set in a 6.5 or 6.2
 
And I have seen multiple chain failures on CUCV's and Hummers while I was in the service
 
yellowK20 said:
I disagree if you can find the gear set run it, No heavy duty Diesel runs a timing chain the cams are ALWAYS gear driven . the timing chain is the one thing I do not like about the 6.2.

The timing issues you speak about on a gas motor are not as prevalent in a 6.2 the engine speeds are much lower as is the engine acceleration its apples to orages comparison

I've not heard ANY complaints about using the gear set in a 6.5 or 6.2
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A agree that other heavy duty Diesels run gears, but they do not the dual idler style set up like the Pete Jackson. They run a gear to gear design which is far superior. I'd argue that is an apples to oranges comparision.

I would personally want to see someone with 100K+ miles on a 6.2 with PJ before I would reconsider trying one. They just wear out so fast on gas motors that I can't imagine them doing any better in a diesel, except that the lower RPM make prolong the wear a little longer. Like I said they do good for a while, I've seen several of them come completely apart. That floating design is just not that reliable for high mileage, at least in my experience.

As far as HMMWV's and miltary 6.2's having timing chain failure doesn't surprise me. The life of a LOT of N/A 6.2's in Hummers was less than 10K. That is not typical of a normal, well maintained 6.2. Most of those Hummers are being absolutely killed by guys in their late teens and early 20's that can tear up an anvil with a rubber hammer!;) (Not knocking, because I used to fit that profile myself when I was that age!)
 
Heavy Diesels do use Idler gears, (with a few exceptions) I chain has way more surfaces for wear to occur and thus way more potential for slop as well as not oiling itself as easily as gears,
 
yellowK20 said:
Heavy Diesels do use Idler gears, (with a few exceptions) I chain has way more surfaces for wear to occur and thus way more potential for slop as well as not oiling itself as easily as gears,
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They use fixed idler gears which is totally different thing than floating dual idler. I totally agree that a gear drive set-up is better, and if there one was one the market that was a fixed idler set-up or gear to gear, I'd have one a 18:1 CR 6.5 I'm building, but I'm just not a believer in the PJ set-up.

Cummins

Timing%20Gear.jpg


7.3 Powerstroke

Forddiesel71709email.jpg


Duramax
0904dp_20_z+7_1l_duramax_stroker_buildup+cam_bolt.jpg


6.2 Pete Jackson

pjj-6-2-d_w.jpg


They are not even close to being comparable. Those dual idlers don't mesh fixed gears together like every other diesel gear drive made. They sit there between the large gears floating around and vibrating. That's what you hear with them. You can't hear other gear drive timing sets because the gears don't move. That's the reason the gear drive on a 292 Chevy 6 cylinder doesn't sound like a supercharger.
 
The Sound is the Square cut gears,

helical cut gears are MUCH quiter,

No I agree that a fixed Idler would is better the floting Idler is still better than a chain.


Not that it really matters even with a chain these engines go ALONG time with no issues. and if your gonna leave the engine stock then put a chain back in it . but if your going for more power go gears.


Another thing to consider is the forces applied to the crank, Pull one apart and you'll notice that the bearing wear on the main journals is the same ........with exception of the front main it will wear the TOP bearing shell this from the chain pulling up on the front of the crank snout. The gear arrangement eliminates this and thus helps eliminate crank breakage.

Some will argue that the gear set-up will transmit more harmonic vibration but I dont see that to be an issue.
 
yellowK20 said:
The Sound is the Square cut gears,

helical cut gears are MUCH quiter,
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That true, but fixed straight cut gears are nowhere even close to being as loud as those Pete Jacksons are. The Cummins (and lots of other HD engines) has straight gears, and they do not sound like that.

yellowK20 said:
the floating Idler is still better than a chain.
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I guess we'll just have to agree to disagree on that one. I have built all kinds of engines for many years, and I just won't touch those PJ's because numerous bad experiences.

I gotta say its refreshing to be on forum that people can disagree without resorting to childish name calling and bashing. I like it here! I appreciate the mature, intelligent discussion, even if we disagree!;)
 
LOL well i was just gonna call you a big poopy head !!

but seriously I have 2 6.5 's with the gear sets one has 630,00 (set installed@200,000)the other has 300,000 (installed at 190,000) and I've had no issues and I have a buddy herein AK that builds 6.5's for marine applications and some trucks and no engine leaves his shop with a chain, ( not sure what he'll do if there not available anymore)

Yep so I guess will agree to disagree . Oh BTW I'm a Generator Tech I'm into a Series 60 right now and I can tell you all sorts of horror stories about 3456 gear train failure and Series 60 bull gear failures lol

IMG_0741.JPG
 
I've seen lots of V8's,both diesel and gas,that had more wear on the number one main bearing surfaces than the others..an old machine shop worker told me he always thought the air conditioning compressor put a lot of load on the frontmost bearing,and its also the farthest one from the oil pump,and probably doesn't get adequately lubed fast enough on cold starts compared to the others..(on a side note,I have noticed just about every engine that needs a rear main seal also has a slightly "loose" rear main bearing,I had to replace the rear main on two of my engines that had a leaky seal..)

The straight six GM's used a fiber cam gear in most applications,later ones went to an aluminum cam gear..I had 3 of those fiber gears srtip out at very inconvenient times!..:mad:..
 
Thats a thought accesories being to tight could cause the upward pressure on a crank snout. I know the diesels I work dont do that to the bearings.

and the wear I speak of is equal its just on the upper bearing and not the lower
 
Gear to gear would require a cam that was reverse ground , because gear to gear would make the cam spin backwards
 
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