New heads, lost torque

[damicotile]

I just put on some new heads from Steve Tims, some stage 2's.
It seems to have lost it's low end torque. It's just not that torquey (sp).
I split the case while I was at it to check the cam and lifters for wear as my old engine before this one went flat after about a couple of thousand miles.
Cam and lifters mic'ed out perfectly BTW.

While I had the case open, should I have changed the cam to match the heads?
I am running a W-120.
Maybe low port velocity?
Anything to bring back the low end torque?
I went from 40x35 to 42x37
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'73 SB
82x94
W-120 w/ CB light weight lifters
Silicon bronze sleeves
Scat 1.25:1
CB H-Beams
Straight cuts
42x37 Steve Tims
44 IDF's
9.2:1
A-1 Sidewinder coated

__________________________________

[Stripped66]

Which heads were on the engine before, are the manifolds port-matched to the heads, did you change the jetting on your carburettors, and did you change your timing?
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[jfats808]

With the 40x35's you may have had more port velocity at lower rpms. With the bigger heads now you seem to have to build more rpms to get the performance out of the head. Valve lash set correct? Try and reset your timing and advance a bit more if possible. Did you rejet your carbs and retune your A/F mixture?
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2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125

[Chuey]

Did you ask Tims what cam would work best? By buying his heads, it seems that he would naturally be willing to help you make them perform at their best.

Chuey

[mark tucker]

addvance the cam about 4-6 degree. but first are they the same cc chambers? is the cr the same?? that might be where it went. those ports are so short port velocity should not be the problem,what about the timing??did you get the gears a tooth off?? If you have a degreed pully you can check the cam timing easy by pulling the vc and a set of rockers and use a dial indacator.make sure your pully has the tdc at tdc if not ,make a pointer. use the positive stop method to find tdc. is it jetted corectly?addvance curve working good? what intake? is it a deferent intake system?I dont think it is the heads. there is somuch that can cause this ,and a lot can be done. deferent header? cam can be addvanced by removing the oil pump to get to the bolts & useing offset washers.you may need to drill the gear out witch might be a bitch, I cant remember. I dont know if you have the gear off by a tooth if you can move it buy removing the oil pump&camgear but if you check the degree and find it is off that would be the first thing I would try Insteaad of spliting the case. good luck.

[damicotile]

The heads I had before were BugPack 40x35 non ported heads.
My manifolds were match ported to these new heads.
The jets are 55 idles, 160 mains and 200 airs.
I did adjust the A/F and sync'ed the carbs plus put on a CSP center pull.
The timing is @ 7.5 at idle and 28 degs advanced with a cast iron 010.
Valves are set to .006 with aircooled's alum push rods.
With the old heads I put in the 60 idles but it was too rich so I took them out.
I may put the 60's back in.
I took it out on the freeway last night and it was so smooth compared to the old heads and reached 98mph lickity split before my son told me to knock it off.
It scared him. He's 17 1/2 yo.
No guts, no glory I say.
Anyway it just has no real bottom end like the old heads had but the top end is awesome.
I'll try advancing it a few degrees and see what that does and then put the 60 idles in after that and see what that does.

I am not about to split the case again for a new cam but really should have asked Greg or Steve about if I should have.
I did tell him which cam I had though.
Sometimes people won't tell you anything unless you ask, and I forgot to ask. My bad.
_________________
'73 SB
82x94
W-120 w/ CB light weight lifters
Silicon bronze sleeves
Scat 1.25:1
CB H-Beams
Straight cuts
42x37 Steve Tims
44 IDF's
9.2:1
A-1 Sidewinder coated

__________________________________

[mark tucker]

main jet seems a little high,but that isant the problem check the cam deg.I didnto notice you had stright cut gears so they should be ajustable just fine. and thats easy to do. just rember witch way to go to addvance the cam. check the head cc on the old heads and ask what they are on the new heads.if you had 9.5 cr befor and now have 8-8.5 there is where it went.but addvancing the cam will still help.you might try a bit more timing but be carfull. 17 1/2 and skeered???at only 98?? my daughter started riding with me on my yz 250 at 5 years old or less.and it wasent fast enough for her then. If I hadent gotten cancer and effed up by mr slice&dice& his kissen coussen raidoactive ray.she would be racing my 800+hp roadster now at 16.but the roadster never got finished.any body want a "new" not finished all round tube roadster?

[RockCrusher]

Too far too fast. I bet you'd have been thrilled if the 40 x35.5 BP's had gotten the port job.

Did you discuss compression with the head builder?

I would start with the ignition timing but consider the cam advance...it really is a pretty good compromise.

RC
_________________
[email protected] Please use email for all general inquiries.

I will be happy to speak to anyone who has a serious inquiry (meaning real potential business for RC enterprises) or a parts order. Due to machining noise causing missed calls all calls will be returned promptly.

[damicotile]

[mark tucker]

then pull the pump and put in the offset ones in the cam should addvance by going counter clockwise.witch would be the gear going closkwise.you dont need to split the case.

[RockCrusher]

Fairly impossible to advance the cam in the car. Do the timing and see how that goes.....Try to go up from 28 now to 30 total to start with. Be real careful about pinging.

You might consider an SVDA to get that nice bottom end drivability without messing up the top end.
_________________
[email protected] Please use email for all general inquiries.

I will be happy to speak to anyone who has a serious inquiry (meaning real potential business for RC enterprises) or a parts order. Due to machining noise causing missed calls all calls will be returned promptly.

[midtravelmidengine]

maybe it just feels like you lost TQ because you gained SOOOOO much top end? Just a thought.
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[mark tucker]

[RockCrusher]

Don't forget removing the exhaust system too, Mark.........Hence the wording "FAIRLY impossible"
_________________
[email protected] Please use email for all general inquiries.

I will be happy to speak to anyone who has a serious inquiry (meaning real potential business for RC enterprises) or a parts order. Due to machining noise causing missed calls all calls will be returned promptly.

[SRP1]

[RockCrusher]

[jfats808]

Ive done it before. You gotta have elf fingers and lots of patience. If you have stubby hands like me x2 lots of patience. Break em all first then remove one by one and swap the washers.Remember to use a long skinny screwdriver when removing the washers so they slide on the shaft or a extendable magnet.
_________________
2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125

[damicotile]

[steve34]

You might put smaller venturis in. That is whyI think a 40 by 35.5 ported head is better for the street and sand.

[mightymouse]

Go drive a bug with a bone stock 1600, no hop back into your car and drive.
You will then stop complaining.
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Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
Thomas Jefferson


Note to EVERYONE.
Know your ZDDP levels or you WILL lose a cam and lifters.