bbc r.rockers 1.7 with 3/8" studs!!

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#16

03-18-2010, 06:43 AM

MBDiagMan

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Respectfully, you're getting all wrapped around the axle over nothing. Longer valve stems do not add any risk factor with high ratio rocker arms as long as the push rod length is checked and correct push rods are used AND valve to piston clearance is checked.

High ratio rockers, if applied correctly are a great street mod. You are increasing valve lift without the downside of more duration. You will need rocker studs long enough for the task and adequate valve cover height.

If you were to use roller rockers in the mod, properly applied with correct push rod and rocker sizes and adequate valve to piston clearance you will be IMPROVING reliability and longevity, not decreasing it. Roller rockers provide much less stress on the valve guides.

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#17

03-18-2010, 11:19 AM

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Quote:

Originally Posted by MBDiagMan

Thanks. I just tend to be wary when I don't have the right amount of experience to make an educated judgement.

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#18

03-18-2010, 02:26 PM

1986F150six

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The above is an example of how gentlemen handle differences of opinion. Thanks!

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#19

03-18-2010, 02:46 PM

gfw1985

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Teach a dummy something, I was under the impression that the cam lift was multiplied by the rocker ratio to get total lift. Ex: .450 cam lift x 1.5 ratio rockers gives .675 total lift.

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#20

03-18-2010, 09:14 PM

Rogue_Wulff

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Quote:

Originally Posted by gfw1985

Teach a dummy something, I was under the impression that the cam lift was multiplied by the rocker ratio to get total lift. Ex: .450 cam lift x 1.5 ratio rockers gives .675 total lift.

Actually, it depends on the cam manufacturer. Some provide lift specs using a specificed rocker ratio only, while others will add the lift specs for alternate ratio rockers.
But, in most cases, the "advertised" lift/duration specs are already factoring in the stock rocker ratio.

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#21

03-18-2010, 11:04 PM

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I took the truck apart today. Dang, I had to remove the ENTIRE grill, not just the left/right inserts as I was hoping, otherwise there would have been no chance to remove the cam. This way I don't have to move the engine.

Someone on the other forum mentioned to only install the 1.7 rollers on the intakes. I'm waiting for an explanation.

So, during this process I'm replacing the radiator with a Summit cross flow, and mounting a dual fan/shroud set up out of a Ford Windstar. The shroud took quite a bit of fabricating, but it should be very nice. That will allow me to use oe hoses (top from an '84 300), and get rid of my copper tubing! It will also allow me to move the trans cooler in front of the radiator. I am also fabricating boot type brackets for the bottom of the rad. on either side.

The cam is coming out, and the original Isky 256 duration supercam is going back in, so I can swap out the clunking timing gears, and the clicking lifters due to a smaller base circle on the cam. Along with the cam I'm putting back in the Isky lifters too.

Before it goes back together, I'm swapping out the oe rockers for Crane 13750 beautiful roller rockers, the 1.7 ratio. That should bring my valve lift to .475. The Chevy 250 I6 runs .492 lift with the same Isky cam!! While I am up there, I'm removing the head bolts one by one, and replacing them with ARP studs. It should make for a good weekend.

Note: There is an oil channel on the drivers side of the block, which sticks out right at the outside of where the cam gear is. You can see an allen plug that can be removed to clear the oil channel. I wonder how many rebuilders clear this line prior to assembly? I'm not talking about inside the timing cover, but it can be reached (the allen plug) on the outside perimeter of the timing cover.

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#22

03-19-2010, 12:55 AM

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valve train geometry check

I found an easy, understandable way to check the geometry between valve, roller rocker arm, and pushrod--and how to determine if you have the correct length p. rod. Keep in mind this is for a v8, so adjust the teminology.

****** http-equiv="Content-Type" content="text/html; charset=utf-8">****** name="ProgId" content="Word.Document">****** name="Generator" content="Microsoft Word 12">****** name="Originator" content="Microsoft Word 12"><link rel="File-List" href="file:///C:%5CUsers%5Cbobby%5CAppData%5CLocal%5CTemp%5Cmsoh tmlclip1%5C01%5Cclip_filelist.xml"><link rel="themeData" href="file:///C:%5CUsers%5Cbobby%5CAppData%5CLocal%5CTemp%5Cmsoh tmlclip1%5C01%5Cclip_themedata.thmx"><link rel="colorSchemeMapping" href="file:///C:%5CUsers%5Cbobby%5CAppData%5CLocal%5CTemp%5Cmsoh tmlclip1%5C01%5Cclip_colorschememapping.xml"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w

oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

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ontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]--><style>  </style><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority

9; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} </style> <![endif]--> Here's where we get down to the how-to details. All you really need to check for proper pushrod length is a black felt-tip marker and a couple handtools. Yank a valve cover and rotate the engine over until the rocker arm of your choice is on the base circle of the lobe. Loosen and remove the rocker arm. Clean the top of the valve-stem tip and then paint the tip with the black marker. Then place the rocker back over the stud and rub the roller tip to create a witness mark on the valve-stem tip. Now remove the rocker arm and look for the mark.<o

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If the pushrod length is correct, the witness mark should be located on the inboard third of the valve-stem tip. If the witness mark is too close to the intake side of the valve-stem tip, the pushrod is too short. If the witness mark is in the middle or toward the exhaust side of the valve-stem tip, then the pushrod is too long.<o

></o

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#23

03-19-2010, 06:30 AM

MBDiagMan

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Push rod length checking is the same on any engine if you're using roller rockers. They make a nice mark on the valve stem tip. You should try to get the mark centered, but with higher ratio than stock rockers, this might not work out perfect.

BTW, I understand your frustration in getting the cam out. When you start pulling the cam out of an I6 you start wondering if it had reached all the way to the back bumper.

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#24

03-19-2010, 09:59 AM

Rogue_Wulff

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LOL, ain't that the truth........ Almost feel like you need a complete empty stall in front of the truck, just to get it all the way out.

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#25

03-20-2010, 12:21 AM

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Today I finally managed to pull the cam out. I could see that the base circle was about 1/8" smaller in diameter than the Isky cam. I thought that was a lot! That was my first and last time to have a shop grind a cam for me.

After trying to get the gear puller on the crank gear so I could swap it out and stop the knocking, I gave up. Short of dropping the crank, I did not see how I could get a puller behind that gear. So I changed the cam gear with the new Isky cam, and lash is down to .002. I am happy with that, same numbers, just different sets of gears, one from each set. I was also happy to see the clicking lifters go.

On the head I replaced the old bolts for ARP studs, one at a time and torqued them, then double checked. That makes me feel much more confident about the head gasket.

I also tested the rollers on the v. stem, and tomorrow I'll pick up new p. rods, about .090" longer. Those new rockers REALLY look nice on the head!! I can't wait to feel how it runs.

I will also post photos of the project, new radiator, new dual fans and shroud for $30! out of a Ford Windstar, and the aluminum cross flow radiator!! It is very nice looking.

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#26

03-20-2010, 07:43 AM

oldbrokecowboy

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More fun

Howdy, long time, no comment. Maybe for the best? I would'nt recomend the miss-match of timming gears, you may end up with a bigger problem than you started with. There is already a wear pattern in the old gear (crank) that the new one won't have. The crank gear should come off with a little perseverance (heat maybe), it's not a press fit, just snug. By heat I mean propane torch, or even hair drier. With the miss-match you may end up with a squalling cat in your timming cover, or get lucky and all will be well. Not a risk I would take with all the hard work and grief you have experienced with this engine. Miss-matching is not recomended by any manufacturer or reputable mechanic with either gear or chain sets. Emergency is one thing but? If in doubt check with the folks at FSP. I don't think lazy jw or french town flyer would go this route if there is a choice.

PS not your dutch uncle, just my .02. Hope all works out well OBCB

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#27

03-20-2010, 11:49 PM

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Glad you're back, OBCB--

Thanks for your concern regarding the t. gears. But I would of had to have remove two of them. Now it's back together, and I'll let you know the result.

Today I installed the r. rockers. They look so nice I wish I could leave the v. cover off. I set them up, cleaned them, oiled 'em, and set preload. I ordered longer p. rods that will be here in 3 days.

Spent the rest of the day fabricating the rad. 'cup' brackets, welding them in, etc., and working on the fan shroud, cutting, applying sealing foam and a rubber sealing flap, and trying to figure out how to install it w/o having to pull the entire radiator every time I want to remove it. It is quite complicated.

My little wire feed welder is one of the best things I ever bought.

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#28

03-21-2010, 07:39 AM

dustybumpers

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I have used the gears off 2 sets before, because of the same problem you ran into, with no problems, although it might be a little noisey, but not clanking like before. this would be a real no no if it were a timeing chain, it could fail in a short amount of time, because the chain could wear quickly, if the teeth were different, and the chain did not line up properly

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#29

03-22-2010, 10:50 PM

oldbrokecowboy

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Glad this is all going to work out. Are'nt those anodized colors pretty. WOW. Keep up the good work and write about it. OBCB

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#30

03-22-2010, 11:46 PM

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OBCB--

I'm hoping it will all work out. If I don't like the performance/milage I get from the rocker upgrade, I'll put the stockers back on and sell the Cranes on ebay and make a buck.

As far as the gears go, I'll soon know how they'll work out.

The geometry did not check out, so I have a new set of p. rods coming Tuesday.

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