When is a Cam Needed?

A few years ago I went from a stock 24V cam in a Ppump 24V with too big of a turbine housing for the amount of fuel I had available to Zach's 200/220 (which I am still running today). The cam swap made it a completely different engine. I could tell night and day difference before the tires started to turn.
 
Texashighways said:
About .050", but you could put it on a 101 instead of a 99 and get even more clearance. ( assuming a standard head gasket that compresses to ~.056" and 1.69:1 rocker ratio with .010"/.020" lash)
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Texashighways said:
Injection pump cams
The .030" is pretty tight. you could retard it and do it later. Call the office if you want specifics. I will have to bring up the file on the computer and look at how many thousandths per degree the cam is moving so that I can calculate how much clearance you would gain. Although we don't usually recommend it, you could even take the lash to .013" to buy you a bit more.
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I called yesterday to see how much clearance I could pickup by retarding the 188/220 cam a degree or two. The person I talked to (Ryan?), said that only the older 97 degree CL cam can be retarded, and that I couldn't gain any clearance by retarding the newer 99 CL cam. He also said that a TDC valve drop test should yield ~ .075", instead of the ~.093" from what your guidelines seem to indicate. He was a little off on some engine clearance specs too.

It's hard to make a informed decision when you're getting conflicting information. :doh:

Sounds like a great cam, and I'm trying hard to buy one, but so far, the numbers aren't adding up for me. If additional clearance can be gained by retarding it, and it's not something you want on the forum, please PM me. Be aware that retarding it would only be temporary until I have time to do a full rebuild and cut reliefs.
 
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I don't know what you talked about, but without knowing all of the piston protrusion and the intake and exhaust valve depth, it is hard to say exactly what centerlines to use to make the cam fit. In any case, I will hop on cam computer at the shop tomorrow and get you all of the clearance data you need. I will see how many thousandths per degree the cam is lifting at TDC and then see how retarding it a few degrees will affect the intake valve to piston clearance and the Exhaust valve to piston clearance.

If you can, P.M. all of your measurements.
 
Can't beat that service.

When cam time comes whether its a CR or a 12v your getting my business sir.
 
this is some fantastic info here. my head only hurts a little now

I had already planned on going hamilton but this has definitely made my choice of which cam I want
 
The 188-220 on a 99 intake center line (24 valve) has .034" intake lift at TDC and .030" on the exhaust. After lash and rocker ratio are factored for there is .037 intake lift at the valve at TDC and .031" exhaust lift at the valve. Moving the intake 2 degrees retarded would create approximately .008" less intake lift and .006" more exhaust lift. .029"/.037"

For reference on a 12v there is still .034"int. and .030"exh. lift at TDC for a 99 intake center line but after the rocker ratio and lash are factored for there is .047" int./.025" exhaust at the valve. If retarded 2 degrees to a 101 intake center line, the 109.25 LSA 188-220 will have approximately .037" int/.034" exh.
 
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Thanks for the info :thankyou2:

Looks like it's too tight unless I go with a thicker head gasket or reliefs though :doh:
 
I apologize, but there was a flaw in my math. Below is the correct lift at TDCE for the intake and exhaust for both the 12v and the 24v at a 99 intake centerline and a 101 intake centerline.

188-220-109.25 on a 99 intake centerline. Lift at the valve
12 valve @TDCE .047" intake/ .030" exhaust
24 valve @TDCE .037" intake/ .020" exhaust

188-220-109.25 on a 101 intake centerline (retarded 2 degrees)
12 valve @ TDCE .037" intake/ .038" exhaust
24 valve @ TDCE .029" intake/ .026" exhaust
 
We installed the 188-220 in a customers truck very recently and the bottom and mid-range spool up is awesome! Hard to believe the difference! Can't wait to see some numbers compared to the old 683 rwhp! Thanks Hamilton!
 
my last 12v had a regrind schied cam in it. wasnt a big cam but could definitely tell a big diff in spoolup and power
 
Yea texashighways, you have me sold when cam time comes!....thats if you are willing to do a 4bt cam?
 
Finally sticking a cam in mine over the next few nights. Since my clearances are tight, I ended up buying more than one cam, and will be test fitting them to see which fits best.

I'm not going to mention brands, except to say that one of them is a Hamilton 188/220. And I do have to say that I'm impressed by the appearance of it, and it looks to be a higher quality cam. It has a larger core diameter and wider, better looking lobes than the others.

Unfortunately, I'm pretty sure it will be too tight. I spent yesterday checking the cams with a degree wheel and dial indicator mapping them out. The lobe lift on the 188/220 is where Zach said it would be. But that's likely going to leave me with .032" Int and .041" Ex clearance (that's on a 100 CL). A little on the tight side! But I'm going to stick it in, and check it anyway.

A funny thing is though. They all have different specs, but checking them at .050" and .200", I was surprised how similar they are. A couple are only 0-1 degree apart.
 
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Who can resurface tappets in the states, been searching but not having much luck. Also have found mixed info as to whether they are truely flat or they are ever so slightly convex or have a crown to them to aid in rotation? Anyone know the correct answer? Could they just be polished up DIY if they look good? What should the surface finish be?
 
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