Straight cut cam gears?

67 newbie · Post by **67 newbie** » Fri Sep 26, 2003 5:31 am

So I am still in the tear down phase of my "winter" buildup of a 1915. I am planning on running ratio rockers and a cam designed for such. Now what is the reasoning for straight cut cam gears besides the noise? If I am using dual valve springs and ratio rockers will the load on the cam be great enough to need them?

I don't want to buy them if its just for the sound, I don't care about that and would rather use that money for something that would give me more bang for my buck...

JC-ATL · Post by **JC-ATL** » Fri Sep 26, 2003 6:46 am

Straight cuts decrease the thrust load on the cam, and obversely, on the crank.

Honestly, I can't think of an engine that "needs" them, and they're too noisy for my taste.

Also, why are going to dual valve springs? Are you planning to rev the daylights out of this thing? (>6000RPMS?) If not, save the load on your valve train and keep the singles.

Guest · Post by **Guest** » Fri Sep 26, 2003 7:04 am

JC-ATL wrote:Straight cuts decrease the thrust load on the cam, and obversely, on the crank.

Honestly, I can't think of an engine that "needs" them, and they're too noisy for my taste.

Also, why are going to dual valve springs? Are you planning to rev the daylights out of this thing? (>6000RPMS?) If not, save the load on your valve train and keep the singles.

Thanks for the info. I bought a set of "new" 044's that have 37.5x42's have been ported and polished... and they already have them. No I probably won't ever rev that high but its nice insurance.. and I may have to with that big of a head on a "small" T1...

67 newbie · Post by **67 newbie** » Fri Sep 26, 2003 7:09 am

Anonymous wrote:
JC-ATL wrote:Straight cuts decrease the thrust load on the cam, and obversely, on the crank.

Honestly, I can't think of an engine that "needs" them, and they're too noisy for my taste.

Also, why are going to dual valve springs? Are you planning to rev the daylights out of this thing? (>6000RPMS?) If not, save the load on your valve train and keep the singles.
Thanks for the info. I bought a set of "new" 044's that have 37.5x42's have been ported and polished... and they already have them. No I probably won't ever rev that high but its nice insurance.. and I may have to with that big of a head on a "small" T1...

Sorry I bought them second hand but they were new.. forgot to log in sorry.

Post by **Marc** » Fri Sep 26, 2003 7:44 am

Find cam bearings with the copper-colored thrust shell, or run double thrust shells, (or even better, double copper shells) and the stock gears will be adequate. Take a good look at the surface of the thrust flanges on the cam, too - some have a pretty rough finish that'll chew into the bearings. Better to polish them smooth and start out with a little more endplay than to put it together snug-but-rough.

Post by **Marc** » Fri Sep 26, 2003 7:44 am

(delete)

67 newbie · Post by **67 newbie** » Fri Sep 26, 2003 8:30 am

Marc wrote:Find cam bearings with the copper-colored thrust shell, or run double thrust shells, (or even better, double copper shells) and the stock gears will be adequate. Take a good look at the surface of the thrust flanges on the cam, too - some have a pretty rough finish that'll chew into the bearings. Better to polish them smooth and start out with a little more endplay than to put it together snug-but-rough.
Another option is to use 36HP gears which have less of an angle, but it's getting hard to find a good set.

So Marc in your opinion is it better to run straight cuts with larger cams and heavy valve springs? Or would this double copper thrust bearings be a better scenario? Money wise is it comparable? If so I may go with the straight cuts. I just pulled my case apart last night... it does have the 10mm studs screwed into the case, all came out fine. Actually the engine had just been through a rebuild the pistons and cylinders are new, still have hone marks in them... all the bearings look new... probably going to use the pistons, crank and rods on a friends super... Got to measure everything but it is looking hopeful...

Post by **Marc** » Fri Sep 26, 2003 8:54 am

Double-thrust cam bearings will only set you back ~$20, even cheap straight-cuts are a good deal more than that. Besides the noise issue, there's no choice of gear "size" in straight-cuts and if they start out loose they'll get even looser (especially the aluminum ones). Personally I leave the straight-cuts for race engines.

67 newbie · Post by **67 newbie** » Fri Sep 26, 2003 8:58 am

Marc wrote:Double-thrust cam bearings will only set you back ~$20, even cheap straight-cuts are a good deal more than that. Besides the noise issue, there's no choice of gear "size" in straight-cuts and if they start out loose they'll get even looser (especially the aluminum ones). Personally I leave the straight-cuts for race engines.

That sounds like a plan to me! thanks again for all the help! my gears look good I will just go with those.

JC-ATL · Post by **JC-ATL** » Fri Sep 26, 2003 9:03 am

Anonymous wrote: Thanks for the info. I bought a set of "new" 044's that have 37.5x42's have been ported and polished... and they already have them. No I probably won't ever rev that high but its nice insurance.. and I may have to with that big of a head on a "small" T1...

Actually, you probably should stick with the dual valve springs - with the heads that big, you're not going to make power until the upper part of the rev range - you may not be able to resist the temptation to rev up there. Of course, that's all dependent on your cam, but with those 1.4 rockers, you're likely to have some pretty aggressive lift.

In regards to Marc's addition regarding the bearings, what he's saying is that you don't need the straight cuts if you polish up the thrust surfaces on your cam, and run the double thrust bearings, preferably the copper-colored ones. (I forgot to mention this because I pretty much always do this.)

(On a side note, is there actually copper in those copper-colored cam bearings? I've used them, I've just never really thought about what they were made of.)

A couple other things - I'm assuming you're going to use a CCW crank on this thing, and you're going to have that case machined for case savers, correct?

67 newbie · Post by **67 newbie** » Fri Sep 26, 2003 9:08 am

JC-ATL wrote:
Anonymous wrote: Thanks for the info. I bought a set of "new" 044's that have 37.5x42's have been ported and polished... and they already have them. No I probably won't ever rev that high but its nice insurance.. and I may have to with that big of a head on a "small" T1...
Actually, you probably should stick with the dual valve springs - with the heads that big, you're not going to make power until the upper part of the rev range - you may not be able to resist the temptation to rev up there. Of course, that's all dependent on your cam, but with those 1.4 rockers, you're likely to have some pretty aggressive lift.

In regards to Marc's addition regarding the bearings, what he's saying is that you don't need the straight cuts if you polish up the thrust surfaces on your cam, and run the double thrust bearings, preferably the copper-colored ones. (I forgot to mention this because I pretty much always do this.)

(On a side note, is there actually copper in those copper-colored cam bearings? I've used them, I've just never really thought about what they were made of.)

A couple other things - I'm assuming you're going to use a CCW crank on this thing, and you're going to have that case machined for case savers, correct?

Yes, I am in the process of tearing down the case now, can't get the oil pump out (don't have the tool) then will send it out for full machining full flow etc...
right now I have the heads I listed and a Demellow CW crank turned .10/.10 and rebuilt rods, and Webber 44's. I got these items from Deano on here at a great deal. THANKS AGAIN MATT! strating to research everything else. I am wanting to make sure I have a good case before I buy any "new" parts.

turboblue · Post by **turboblue** » Fri Sep 26, 2003 3:31 pm

67

If you remove two of the oil pump studs, you can go ahead and split your case. Might save you some time if you are waiting on a pump puller.
I assume you are using a later model engine case for your build.

vwpride73 · Post by **vwpride73** » Fri Sep 26, 2003 5:29 pm

What company did you get the straight cuts from? Some reguire you to grind the cam gear bolts down to clear the oil pump. I had to do that today... A customer wanted to use his empi straight cuts and his Shadek 26mm oil pump, so when I went to blueprint the engine I had to grind the bolts down a little to not have the bolts hang-up on the oil pump.

67 newbie · Post by **67 newbie** » Sat Sep 27, 2003 7:24 am

vwpride73 wrote:What company did you get the straight cuts from? Some reguire you to grind the cam gear bolts down to clear the oil pump. I had to do that today... A customer wanted to use his empi straight cuts and his Shadek 26mm oil pump, so when I went to blueprint the engine I had to grind the bolts down a little to not have the bolts hang-up on the oil pump.

I don't have straight cuts.. probably won't use them since I don't see a point in spending the extra money. I am on a pretty tight budget so I want to spend the money where it counts and save on things that aren't really necessary. Thats why I want to build this engine myself and buy as many parts as I can from swap meets etc.. save my money so I can get all the machining, new P&C's, cam etc... some things you can't buy used, or I won't buy used... like wear items.

Turboblue= Thanks for the tip I will try that..

RT · Post by RT » Sat Sep 27, 2003 9:40 am

Berg sells the DT bearings that are copper faced. I can't recall the make - maybe Glyco. Seems odd that other VW stores I've dealt with can't supply DT copper bearing sets yet they sell non-copper DT bearing sets from the same manufacturer as Bergs. I've had the boxes side by side.

It all comes down to how good your purchaser is.