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Tighten up a street driven HEMI (long?) #2512211
06/23/18 03:25 PM
06/23/18 03:25 PM
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Hemi ragtop Offline OP
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The questions in this post are aimed at the engine builders on here that KNOW the answers!
I developed the desire for a 426 HEMI when I was 10 or 11. Richard Petty was having one of the best seasons in history in a square body, 426 HEMI stock car. I decided then to own one of these cars.
Finally in the spring of 2012, I was driving a square body convertible with a 426 HEMI. Everything about the car was designed to be DRIVEN. First it was a convertible, next was power steering and brakes. I also mounted a Gear Vendor overdrive ahead of the Dana with 3.54 gears. The 727 shifts AUTOMATICALLY with the help of A&A components and a Turbo Action valve body. The converter is as tight as PTC could make an 11", 250K+.
I've enjoyed driving it over 7,200 miles now, It is just what I wanted with just one problem, it uses WAY too much oil. I have won all the "Best of Show" trophies I want, won at Pigeon Forge 8 times in a row, now I want to DRIVE the car, a lot!
I have an extensive collection of original car magazines with many HEMI cars tested new. I know that a lot of them complained that they had to add a quart of oil for every tank of gas, but I am not satisfied with that. I have decided to pull the engine apart over the winter and "tighten it up".
I have chased the oil consumption through intake gaskets, Superformance cured that, leak down, compression checks, catch valve in line to the PVC, all to no avail. I suspect valve guides/seals, but conversations with the BEST HEMI engine builders (you know who I'm talking about), have convinced me that it is a combination of cylinder sealing and guides/seals.
So, who makes the best piston that has the lowest expansion rate? How tight can I run them? I currently have "Diamond" with 4.35" bore. If I need to, I am prepared to bore the block and buy new pistons. What ring size is readily available after 4.350? Richard Nedbal's book suggests a Napier second ring with a "gapless" top ring. I have a GOOD shop that will get the bore straight and put the proper finish on the cylinder walls. What brand ring do you guys suggest? What wall finish? What ring gap? What type of rings?
Next, the heads. I might as well step up to a new, better head. I am currently running MP but am looking at the Edelbrock or Stage V. How tight can I run the valve to guide? What type of seals?
I have lost track of the engines that I have built over the years. The last one was a Gen I HEMI with a 6-71 blower for a 32' roadster that has never had a valve cover off since I put it together in 2009! I want my HEMI to be like the LS-7 that I built and installed in a 70' Chevelle with air, PS, PB, tilt etc. in 1995. I drove that car ANYWHERE I wanted and NEVER had to add oil! It is still running strong and dependable.
Any and all info would be appreciated. What I want is real, tested solutions by real engine builders.
Thanks

Air Cleaner 42.jpgIMG_20161005_070001136_HDR.jpg
Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512218
06/23/18 03:40 PM
06/23/18 03:40 PM
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Kansas Roads Between 0 and 140...
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EV2Bird Offline
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Funny posting.

Could of summed it up just saying, "Hey I need to build my hemi to use less oil".

From your posting it sounds like you might be a under qualified hemi owner but a over qualified chevy guy.

Re: Tighten up a street driven HEMI (long?) [Re: EV2Bird] #2512226
06/23/18 03:52 PM
06/23/18 03:52 PM
Joined: Dec 2006
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Hot 340 Offline
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Originally Posted By EV2Bird
Funny posting.

Could of summed it up just saying, "Hey I need to build my hemi to use less oil".

From your posting it sounds like you might be a under qualified hemi owner but a over qualified chevy guy.
haha

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512232
06/23/18 04:21 PM
06/23/18 04:21 PM
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HotRodDave Offline
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I am no expert but I run low tension napier second, low tension oil and top rings, the fresh short block (410 SB) would turn over like an old worn out 273 with glazed over walls that burns a ton of oil but this thing never uses oil. This is basically the ring recipe that GM used on the LS motors to fix the oil consumption issues they had. I am running diamond pistons, dont remember the number but we set them to the tightest diamond recomended.

I would also run the bearings all on the tight end of acceptible with a high quality shop doing the work to make sure they are in all the specs like taper, roundness, diameter... everything, not just a quick check of diameter in one place. This will lower oil volume through the engine and a good oil pan and windage tray set up. Then you can run a standard volume pump and keep everything lubed while reducing excess oil on the cylinder walls.

No reason a hemi has to use a bunch of oil.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512245
06/23/18 05:19 PM
06/23/18 05:19 PM
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Just use modern parts and your engine will work like a modern one. I have a Toyota 4Runner with 200,000 miles on it and it barely uses any oil.

EFI is one of the best things you can do for engine life since it keeps the cylinder walls from being washed down. Do you have a wide band on your Hemi? If not you should install one and see what is going on. More likely than not you're running 11:1 AFR while cruising down the road and washing the cylinder walls.

Hone with a torque plate, use metric rings, use o-rings or modern gaskets everywhere, etc. It can be done, just takes a careful machine shop. Lots of Hemi guys build drag race engines and they don't really care about oil consumption so you have to find someone who is more familiar with modern stuff and the newest parts that are available.

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512253
06/23/18 05:48 PM
06/23/18 05:48 PM
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Washington
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Originally Posted By Hemi ragtop
The questions in this post are aimed at the engine builders on here that KNOW the answers!
I developed the desire for a 426 HEMI when I was 10 or 11. Richard Petty was having one of the best seasons in history in a square body, 426 HEMI stock car. I decided then to own one of these cars.
Finally in the spring of 2012, I was driving a square body convertible with a 426 HEMI. Everything about the car was designed to be DRIVEN. First it was a convertible, next was power steering and brakes. I also mounted a Gear Vendor overdrive ahead of the Dana with 3.54 gears. The 727 shifts AUTOMATICALLY with the help of A&A components and a Turbo Action valve body. The converter is as tight as PTC could make an 11", 250K+.
I've enjoyed driving it over 7,200 miles now, It is just what I wanted with just one problem, it uses WAY too much oil. I have won all the "Best of Show" trophies I want, won at Pigeon Forge 8 times in a row, now I want to DRIVE the car, a lot!
I have an extensive collection of original car magazines with many HEMI cars tested new. I know that a lot of them complained that they had to add a quart of oil for every tank of gas, but I am not satisfied with that. I have decided to pull the engine apart over the winter and "tighten it up".
I have chased the oil consumption through intake gaskets, Superformance cured that, leak down, compression checks, catch valve in line to the PVC, all to no avail. I suspect valve guides/seals, but conversations with the BEST HEMI engine builders (you know who I'm talking about), have convinced me that it is a combination of cylinder sealing and guides/seals.
So, who makes the best piston that has the lowest expansion rate? How tight can I run them? I currently have "Diamond" with 4.35" bore. If I need to, I am prepared to bore the block and buy new pistons. What ring size is readily available after 4.350? Richard Nedbal's book suggests a Napier second ring with a "gapless" top ring. I have a GOOD shop that will get the bore straight and put the proper finish on the cylinder walls. What brand ring do you guys suggest? What wall finish? What ring gap? What type of rings?
Next, the heads. I might as well step up to a new, better head. I am currently running MP but am looking at the Edelbrock or Stage V. How tight can I run the valve to guide? What type of seals?
I have lost track of the engines that I have built over the years. The last one was a Gen I HEMI with a 6-71 blower for a 32' roadster that has never had a valve cover off since I put it together in 2009! I want my HEMI to be like the LS-7 that I built and installed in a 70' Chevelle with air, PS, PB, tilt etc. in 1995. I drove that car ANYWHERE I wanted and NEVER had to add oil! It is still running strong and dependable.
Any and all info would be appreciated. What I want is real, tested solutions by real engine builders.
Thanks




If you have to go in and tell your builder how to build the engine, you need a different builder. I don't know a single engine builder (myself included) who will let the customer come in and tell them what rings to run, how to finish the bores, what guide clearance to use and all that.

The engine doesn't know it's a Hemi. It has no idea what it is. If your rings don't deal, it's not because it's a Hemi. If the guides are loose it's not because it's a Hemi.

A Hemi is no different that any other internal combustion engine.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512258
06/23/18 06:01 PM
06/23/18 06:01 PM
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fredericksburg,va
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One big reason, the exhaust valve is usually submerged in oil. Get the best valve seals and go over the drain backs in the corners of the head, there's a lot of oil leaks in the rocker assembly up there. At speed I wouldn't be afraid to say 50% or more of the oil capacity is up in the heads. Get a piece of welding wire 1/16 , bend and attach so the end sticks down a little in the center of the hole, this helps promote flow since oil can't swirl in. Can't remember who told me that but it was way back before the turn of the century.

Last edited by cudaman1969; 06/23/18 06:10 PM.
Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512288
06/23/18 07:58 PM
06/23/18 07:58 PM
Joined: Jul 2009
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Norway (old world)
Oyvind Mopar Offline
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Beware of one major Hemi-problem, that the rockers sometimes do not line up well and try to push the valvestems away. (Too short, and wrong geometry) This, along with coarse finish on the valvestems can eat the guides after a short while. And the MP alu heads have valvestem clearances same as iron heads, way more than needed on alu heads. When building a Hemi you need special attention to the heads, or you will get an oilburner....

Re: Tighten up a street driven HEMI (long?) [Re: Oyvind Mopar] #2512345
06/23/18 10:56 PM
06/23/18 10:56 PM
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Hemi ragtop Offline OP
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Thanks for the replies. I didn't mention bearings, what is the tightest clearance that you run? I use Brad Penn 10-30 and have 80lb. cold and 25lb at 850 rpm idle. When hot, I have 60-65lb at 5,000 rpm.

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512349
06/23/18 11:04 PM
06/23/18 11:04 PM
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What guide clearance, bearing clearance and tightest piston to wall clearance do you use for a 6,000 rpm street engine?

Re: Tighten up a street driven HEMI (long?) [Re: Oyvind Mopar] #2512353
06/23/18 11:07 PM
06/23/18 11:07 PM
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Originally Posted By Oyvind Mopar
Beware of one major Hemi-problem, that the rockers sometimes do not line up well and try to push the valvestems away. (Too short, and wrong geometry) This, along with coarse finish on the valvestems can eat the guides after a short while. And the MP alu heads have valvestem clearances same as iron heads, way more than needed on alu heads. When building a Hemi you need special attention to the heads, or you will get an oilburner....


So could the problem be isolated to the heads? Leak down, compression tests all look good. No blow by that I can see. The glass catch can between the PVC and intake never collected oil?

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512388
06/23/18 11:50 PM
06/23/18 11:50 PM
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Yes it could quite easily be a guide/seal problem. My last two Hemi's had Stage V heads prepped by Tim Banning and after running Hemi's since 1980 I was very impressed these two didn't use any oil. They both ran CP pistons speced by Tim as well. I can't remember the clearances though.


Sheldon
Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512420
06/24/18 12:49 AM
06/24/18 12:49 AM
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Bend,OR USA
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All the good hemi engine builders and hemi machine shops I dealt with when I ran 426 Hemi motors in NHRA stock class set the intake valve stem to guide clearances at .0000 to maybe .0002 cold on the stock iron heads, around .0015 to .0019 on the exhaust side cold work
On the Stage V aluminum heads I would use similar clearances for a street motor, make sure the motor has some heat in it, warmed up to at least 100F + before revving it above 3500 RPM twocents
I would do a quick check of the clearances by moving the valves up and down in the guides with no springs, keeper or retainers on them first, if they slid up and down easily and no rocking side to side or forward to backwards clean I would use them and oil them up and install the seals and go racing up
No oil consumption in any of those motors shruggy
We where using stock type TRW or Speed pro 5/64 file to fit rings back then also shruggy

Last edited by Cab_Burge; 06/24/18 12:50 AM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Tighten up a street driven HEMI (long?) [Re: Cab_Burge] #2512485
06/24/18 09:45 AM
06/24/18 09:45 AM
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Hemi ragtop Offline OP
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So Cab, do you think that the guides could pass a quart of oil in one tank of gas? 200-250 miles?
Do you suggest I just pull the heads in the car and replace them and see what happens?

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512494
06/24/18 10:45 AM
06/24/18 10:45 AM
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My Street Hemi had an oil consumption issue when fresh even though it had been rebuilt by a reputable Hemi SS racer. Turned out to be 2 problems: it was way rich, washing down the bores (you could literally smell gas on the dipstick), and oil was getting past the guides. Correcting the carbs fixed the 1st issue. Installing oil seals on the guides that were high-heat silicone (got them from Silver Seal) cured the 2nd. After that the car ran cleanly even with a fairly big cam, and quit drinking oil.
I agree on the geometry thing; you can see how the springs that kind-of locate the rockers allow side movement; Landy came up with a collar arrangement back in the day that fixed that.

Re: Tighten up a street driven HEMI (long?) [Re: topside] #2512577
06/24/18 01:36 PM
06/24/18 01:36 PM
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Yes: I always run the collars too.


Sheldon
Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512644
06/24/18 03:51 PM
06/24/18 03:51 PM
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Mt. Eden Ky.
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I might as well step up to a new, better head. I am currently running MP but am looking at the Edelbrock or Stage V. How tight can I run the valve to guide? What type of seals?


If the MP heads have the original guides, I would start looking there. They were over-sized and soft from the factory. I had a new Hemi build, with new alum. MP heads that was smoking. It was the guides!
I sent the heads to Modern Cylinder heads, and the problem was solved.



Mark


http://marsh-racing.com/Mark%20Mahorney-Allstate.htm
1996 Ram 1500 Sport
1968 road runner
1952 Sears Allstate licensed, pump gas, Hemi 5.98 @ 115.73 1.33 60 ft. The best is yet to come.
Re: Tighten up a street driven HEMI (long?) [Re: Hemi Allstate] #2512669
06/24/18 05:41 PM
06/24/18 05:41 PM
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Tennessee
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Hemi ragtop Offline OP
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Thanks for the info guys, This is what I needed!

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512676
06/24/18 05:59 PM
06/24/18 05:59 PM
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fredericksburg,va
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It don't matter what head you use, just need good guides and seals

Re: Tighten up a street driven HEMI (long?) [Re: Hemi ragtop] #2512942
06/25/18 11:23 AM
06/25/18 11:23 AM
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Marion, South Carolina [><]
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Hemi Ragtop...it sounds like you have a ring seal issue to me.

My 572" hemi is more of a race build that's streetable, but it doesn't use oil. I've never had to add any to it. Been running it since 2006. I don't drive it as much as I used to. Having kids put a damper on that, lol, but it used to see a lot of street time. Not to mention track time.

The first 2 freshen ups, the valve guides and valve stems were worn. First freshen up in fall 2008 I just put in new valves, tightened it up so I ran it for 4 more years like that.
This last time I had bronze liners installed along w/ new valves...that was over the winter of 2012/2013.
I still use the factory style springs to locate the rockers...may contribute to the guide wear problem?
I have MP aluminum heads from the 2005 production range.
I use the teflon valve seals on the intakes and NO SEALS ON THE EXHAUSTS.

My main clearances are .0035" and rods are at .0023-.0024 w/ coated bearings.
Piston to wall is .0075".

I'll be freshening it up here soon. Hoping to get it on the stand and apart in the next month or so.


CHIP
'70 hemicuda street car...8.91 at 150.5 mph w/ 4.10s, 8.97 at 152.5 mph w/ 3.54s so far
'69 road runner 440 w/ Indy SRs
'69 road runner 440-6, 4 speed...Dad's ride
'71 Demon 340 resto project
'06 GMC 2500HD LBZ Duramax...toy hauler
'16 Grand Caravan SXT...baby hauler
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