Bobby Wood's Cams and choices

[David Jackson]

Hi Mike;

When I asked you about cams for my motor (113", HTCC CNC Ported, Boarzilla, 51mm CV) you suggested, among others, a Wood cam TW9B. I looked it up and it looks good. I called Bobby Wood again (he is always courteous enough to talk except when super busy, then he actually calls back. Quite a contract to Customer Service at the HD factory where techs won't even talk to me.) and told him my weight (250 lbs) and my bike; and he once again recommended the 408G. You and I talked about that cam and you expressed the feeling that it is just a low rpm torque cam. I did not tell BW that but I did ask him what kind of revs would work with that cam and he asked me if my bike would rev to 9,000 rpm. Well, I said of course not. the piston speed would be out of sight. He also suggested going to the 3.37 gearing; saying it would only add 125 rpm (seems like that can't be right) to top gear revs.

It's kind of hard to argue with the man who makes the cams ... he said he would sell me whatever I want, of course, but he really recommended that cam, saying it was especially made for folks like me.

Any thoughts?

Regards;

David Jackson

[Mike]

I respect Bob a lot but I just think that the 408 does not have enough duration and has too high static pressure. I strongly feel we will have detonation issues. I'm always willing to try new things and be proven wrong but I also have to consider past experiance. The 3.37 gearing would help because the motor load would be reduced a bit and allow the bike to accelerate quicker. Also, higher altittudes may be more able to accept these high cylinder pressures. Last, a lighter bike may also be more compliant but we typically want MORE cam in lighter bikes because we can focus more on hp than tq for all the above reasons. I would go back to the TW9B or TW62, IMHO.
Thanks, Mike

[David Jackson]

Hi Mike;

Thanks a lot for your input.

A couple of other things occur to me based on what HD says about the heads I have. They are rated for .650 lift and the TW9B has .630 lift which means no problems here I hope. The SE 264 I ran before had .635 lift with no problems. The TW 9B has a little less duration than the SE 264, and of course, different valve timing.

Do you suppose that cam will move the powerband down the scale a little bit from where it was with the SE264? I hope so! What part of the rev range would you expect the most fat part of the powerband to be in with these cams?

I might not change the gearing to 3.37 for a while and see how I like it with this cam just the way it is.

I will need to use adjustable pushrods I should think; do you like the SE adjustable pushrods or some other kind?

Regards;

David Jackson

[zigzzagz]

not mike but the 9b torque will peak lower than the 264.

[zigzzagz]

lower in the rpm band I should add. you may actually see more peak torque power. Bobs cams are known for big torque, and the 9b has an earler close, less duration and lsa that lends itself to big torque early compared to the 264

[David Jackson]

Hi Zigzz and Mike;

I spent some time looking over different cam specs and came up with two choices (I am sure there must be more) which are :

The T-MAN TR 650 and the Wood's TW9F.

Mike, I think the T Man cam set is one you recommended to me in a previous thread. I think the Wood's TW62 G might be a bit much for my heads and the long duration of 262 degrees puts my powerband back up there as it was with the SE 264s doesn't it?

The SE HTCC CNC Ported heads I have are supposed to support up to .650 lift, and that's what this cam (the Wood's TW 9F) has. The lift at TDC is actually almost the same as the .se 264s; just .001" more on the intake side. The SE 260, which should be OK with all the SE parts actually has more lift in the intake side at TDC (.236") than the Wood TW9F has.

Zigzz; I found an old post you started on the HTT site in Dec of '04 asking about various cams, including this one. I wonder what you found out? The messages I got seemed inconclusive and if I have the right power curve sheet that does not help much either.

Zigzz; you also mentioned the Wood's cams being known for torque and that I might have more peak torque with the 9B (than the SE 264 I guess?) that would be fine. I might hope for more torque from the 9F also; and a lower peak power point too.

Anyway the Wood's TW9F is the way I am leaning right now; possibly with a T-Man polished intake manifold.

The TW 9B and TW 9F are close, but since my heads are supposed to flow well I hope they can take advantage of the slightly longer duration and the slightly greater lift which the TW 9F cam set has.

Any thoughts?

Regards;

David Jackson

[David Jackson]

Well ... after all my figuring and thinking ... I called Bobby W just a few minutes ago and chatted about the cams, my heads, etc. etc.

Sadly, I have become a little bit, how shall I put it, gravitationally challenged? In other words I weigh more than I should. Because of that the 408Gs should help me. He even has them in 124" motors!

In the end I did listen to him and I am going with the 3.37 gears and the 408 G cams.

I asked about detonation, etc. etc. cranking pressure, etc. etc. and he said "no problem". He told me that the cam I wanted to get ( the 9F) would work if my compression where higher. I asked about a low rpm cam "running out of breath"; he told me that the short duration is not as short as I think it is; in the '60s he said small block Chevvys were running 7,800 rpm with 221 degrees and here we have 248 degrees.

A side benefit to keeping the rpms down; the piston speed won't be crazy either.

Time will tell, of course; but this should be a good "out of the hole" setup, I will just have to get used to short shifting I guess. We shall see.

Many years ago I had a 73" CH in a lightweight Belland frame, (a half mile frame changed a bit for street use) and I had Sifton .510 cams in it. It started to run hard at 2,500 rpm and that was kind of neat. (With different than street gearing it still went 141 mph at Bonneville, though.) Maybe that's what this set up will be like.

Regards;

David Jackson

[Mike]

I BELIEVE GRAVITY GETS STRONGER AS WE AGE!! SHOULD BE VERY STRONG DOWN LOW.
THANKS, MIKE

[zigzzagz]

What compression do you have that he wants you to run that cam? I know he likes cranking compressions in the 215 - 225 range and suggests the 9f at 11.3 - 11.5.

zigz

[David Jackson]

Hi Zigzz

I thnk you are absolutely correct.

I called and told him I wanted the 9F cams and he asked me if I had at least 11 to 1 compression. He mentioned shaving the heads to get there but somehow I have the impression that the way the HTCC CNC ported heads and pistons are made it is not a good idea to shave those heads. But he all but refused to sell me the 9F cams because he did not think they would work right for my bike.

Your bike is a 124 isn't it Zigzz? Give BW a call, he is happy to chat about HDs. He did tell me he has put 408Gs in 124s but you may be looking for more absolute horsepower than the 408Gs deliver.

I hardly ever ride over 100 mph, and then only for brief spurts, so these cams should be good for me. After all the hemming and hawing I did about what parts to use, now I can't wait for the bike to be ready!

Maybe next year Mike will be casting heads and grinding cams so we can get the goodies from him!

Zoom Zoom!

Regards;

David Jackson

[zigzzagz]

You know you can send those heads to Axtell and have the chambers cut to work with the axtell pistons. Gives you alot more options on compressions you can use. Mebbe Mike will comment on that or has some experience with it. Dave Cote from HTT did it with his CNC HTCC heads and the result was great. Mind you he also had Dan Baisley the head god work the heads for him.... not that it matters now as he has picked up those rev perf billet heads.
So, what is your compression now??

zigz.

[David Jackson]

Hi Zigz;

I don't really know what the actual compression (cranking pressure) is going to be. I think the little race booklet from HD says the HTCC CNC ported heads and 113" jugs with appropriate pistons is suppoed to be 10.5 to 1. I have nothing to go on as far as that little booklet's accuracy goes, no reason to disbelieve it though. BW certainly thought that was not sufficient for the 9F cams; he said he would compromise with 9Bs, but I after we talked back and forth for a bit I figured well, I might be best off to listen to the man who makes the cams!

If this combo works out to be too weak or something then I would think aftermarket is the way to go. I still think of the way no tech people from the factory would talk to me; unbelievable. Spend all this dough (over Fifty Thousand Dollars !!) on HD bikes and HD parts and the factory could care less. They forget where their support comes from, I think. Oh Well.

I bet you are right and Baisley is probably the way to go next winter. I can probably go with different cams (the 9Fs,) and slugs & heads and not break the bank? Until then I am really looking forward to this little bike when it gets done.

I too, am interested to hear Mike's response to your query about longer runners.

Regards;

David Jackson

[David Jackson]

Hi Zigz;

So, what happened to Dave Cote's old heads?? And cylinders? And Pistons? Are they the 4.060" bore same as the HD 113" kits?

David J.

[Mike]

At this time I do not believe Axtell has pistons for the 4.060 bore. Chase (Axtell Sales) and I talked about this and they may introduce some in the future. T-man may also have something similar in the future. Yes, the heads can be machined to match a 20 or 30 degree piston. The problem is a lot of material has to be removed to get an effective quench and correct compression. High TDC lifts and big valves make this worse. Axtell, Baisley or Latus can do this (Latus whould normally do it only if we were assembling the motor so that CC's could be checked and corrected as needed).
Regards, Mike