Andrews J cam for stock 1984 7.4:1 compression engine?

[guppymech]

My stock "S" cam needs to be replaced. I have a Andrews #1 cam on the workbench but am wondering if a "J" cam might be a good choice also for a low compression '84 FXE?
Thanks for any thoughts. Tom

[Ohio HD]

Between those two, I'd take the #1, you'll see more low and mid power.

[Reddog74usa]

 

[Hybredhog]

Between those two, I'd take the #1, you'll see more low and mid power.

  Absolutely, a J grind is kind of a waste of money over stock unless you have a lighter bike with more compression(9.5+), and short gearing. I almost exclusively use the #1 or #2 with 80" & good ports on most shovels I rebuild, and you can throw some taller gearing at it.

[Burnout]

Low compression is not going to support a hot cam well.

You want something that closes the intake valve pretty/very early like high 20's I'd guess.
You could press off the gear and advance a non-stock cam as long as it is not too hot.
You can't push this too far though.

Also a compromised exhaust will cripple any efforts to make power.
Compromised exhausts are,
Drag pipes
Anything short, anything over length, anything fat.
Straight through mufflers
Anything with an abrupt merge.

I'd raise the compression, thin head gasket & remove the base gaskets. Or trim the cylinders so the pistons come all the way up.

[guppymech]

Thanks for the thoughts Guys  The only deal with the #1 right now is that the inner lobe hits the crankcase boss for the pinion bearing and I'm reluctant to grind on it because of the debris generated.

Tom

[Ohio HD]

No way that #1 cam should hit anything, it's only 0.427" lift. A 0.485" lift goes in them with only valve spring changes.

[guppymech]

No way that #1 cam should hit anything, it's only 0.427" lift. A 0.485" lift goes in them with only valve spring changes.

One would think but it absolutely hits, I measured the cam lobe height and it specs out to 0.427 factoring in the rocker arm ratio.  I would post a pic but I've temporarily re-installed the stock cam until I decide what to do....winter in Chicago.

[Ohio HD]

You had the cam thrust washer and spacer in place?


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[guppymech]

You had the cam thrust washer and spacer in place?

Yes, I had both of them in place.  With the cam gear meshed with the pinion gear and I could see no air gap between the lobe and the crankcase.

[JW113]

I'd grind it. I had the same problem with a '80 sportster, had to grind the pinion boss. Just need to use lots of saran wrap & grease, shield the cam chest all around the pinion shaft, including the pinion shaft, and use a shop vac with an upholstery tool to make a "funnel" to catch the chips as they fly off the cutter. Then hose it all down real good with brake cleaner. No worries.

On the other hand, with 7.4:1 compression, the stock cam is likely to work just fine.

-JW

[guppymech]

Here's a pic I just took.  It's not directly hitting but there isn't more than a couple thou.

[Ohio HD]

You put that cam cover on and the cam will lift upward about 0.010" to 0.015".

[guppymech]

You put that cam cover on and the cam will lift upward about 0.010" to 0.015".

With the cover on I had trouble fitting a .003 feeler gauge.  Maybe I'll try the grease and saran wrap like JW mentioned. 

[Ohio HD]

Take some vinyl electrical tape, without stretch it, fold it over adhesive side together, measure the thickness with calipers. Double thick should be about 0.012". Wrap three laps around the rear lobe, without stretching the tape, but tight. That should give you close 1.5x the original measure you had. Cam in cover on, slowly roll the motor over to see if the tape drags on the case.

[guppymech]

I did two layers of tape and tried to install the cam with the lobe pointing down at the point of minimum clearance.  I couldn't get the cam to fit like that, the tape hit the edge of the crankcase and started to bunch up.  I realize you said to rotate the engine to spin the cam but I didn't want to jam the cam and possibly damage the lobe.  The clearance just isn't there.

[Hybredhog]

Here's a pic I just took.  It's not directly hitting but there isn't more than a couple thou.

    I seen that & I have a '82 here that I'm putting a #1 into, and it has approx. .010" room to the case race. I've been using #1 for years, and I happen to have a J grind here also. The base circle on the #1 is .125 over the shaft center dia. (.815), and a J is .132" over shaft dia. A #1 total lobe height is 1.365", and a J is1.340", make a #1 lobe only about .018" taller than a J. I would grind some material away if it'll let you sleep better, but odds are you'd be OK. If a cam lobe ever moved that much to hit the case race, you have bigger problems than that & the cam bearing/cam race is gone. Just pack the cam bearing with a paper towels (should get replaced anyways), and everywhere else too, and grind away, then douche the chit out of it afterwards.

[guppymech]

I just got done grinding the case and all is good.  I used some 2" wide clear tape similar to electrical tape to protect the entire gearcase, no filings got out.

While I've got your guys attention, Do you think I need to check valve guide seal to spring retainer clearance?  A couple years ago I had the heads first valve job done and viton seals where used (instead of stock K-Line type) along with NOS H-D red stripe valve springs.  The machinist and I talked about maybe using a #1 cam but there are no notations on the work order that clearance was verified, I recently talked to him and he didn't remember (he's very busy).  I was planning on pulling the front head to check but if youse guys know yea or nay that would be great.

[Ohio HD]

It's winter in Chicago, I'd go ahead and check. Should be OK, but....   better safe than sorry.

I'd also set that cams end play to 0.010" if you haven't already. I seem to remember later Shovels they started making a huge end play speck for the cam. Something like up to 0.050" if memory serves.

[Hybredhog]

   Actually the Viton guide seals take up less travel than K-line seals, not to mention work better & stay put. K-line seals use approx. .125" of travel, and Viton's of that size that I've used are under .100". It's rather deceptive, but K-lines don't press down as far as it may look inside of the seal.
   
   I believe the factory didn't get lazy about cam end play until about '94ish when they went with the back washer without the ears, 25550-57A.

[guppymech]

Thanks for the reply Mr. Ohio and Jeff's Cycle.  I ended up with .009 endplay on the used gasket with .065 shim.   I'll probably pull the head to check, just not today, won't be able to ride until the end of February at the earliest.   I'll update the thread with what I find. 

[guppymech]

   Actually the Viton guide seals take up less travel than K-line seals, not to mention work better & stay put. K-line seals use approx. .125" of travel, and Viton's of that size that I've used are under .100". It's rather deceptive, but K-lines don't press down as far as it may look inside of the seal.

That is some good info.

[Ohio HD]

   
   I believe the factory didn't get lazy about cam end play until about '94ish when they went with the back washer without the ears, 25550-57A.

I think you're right, it was Evo years.