273 questions...a few of them

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Steve, I just looked at an article and the builder named several cams for the 273 and guess what was at the top of the list, you guessed it, the one you have. He also says the only thing needed is the matching springs.
 
hmmm.... i guess it is entirely possible the pistons have been switched out somewhere down the line... but even so , its not like we are talking about a .509 lift or something....
 
I'm sure you have a problem with cam timing. i ran a 484 in a 318 a 535 in a 340 and a 606 in a 440, all way above the stock lift and had no clearence problems. you are either opening to soon or staying open late. pull the heads, yea your gonna need new gaskets and check your pistons and get a proper TDC. install your head without a gasket and check the specs of the cam against the card.
 
Mikes270dart said:
I'm sure you have a problem with cam timing. i ran a 484 in a 318 a 535 in a 340 and a 606 in a 440, all way above the stock lift and had no clearence problems. you are either opening to soon or staying open late. pull the heads, yea your gonna need new gaskets and check your pistons and get a proper TDC. install your head without a gasket and check the specs of the cam against the card.
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I don't see any need to pull the heads.....................................
 
maybe its just the factory springs binding up...
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My thinking also. Have your cam in the 273 commando in my Valiant with absolutely no issues, but my heads have the comp cams recommended springs. Also from my experience definitely adjust your intake/exhaust to the cam spec sheet numbers not factory numbers. These springs are cheap. You need them.
http://www.summitracing.com/parts/CCA-901-16/
 
Add this to another list of stupid questions, but is there different degree wheels for different cams?? If I dont have to, I dont want to have to order one from comp, I would rather get one from a local speed shop, use it and see if that solves the problem. Dont wanna wait over a week for a f'n degree wheel.
 
Google printable degree wheel there are lots of sites, just resize and print, cut it out and fasten to a piece of cardboard
 
Just got off the phone with "badsport" and he may have hit on what the problem is......:-$ will keep ya posted! Thanks Bruce
 
Ok well I think we fingered out the problem, but wont know for a couple days, we gotta replace 2 bent push rods then re-check it......
 
did you have to degree this cam when you installed it?
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Did degree mine but would think it would not be necessary with that lift, matched springs & otherwise stock components. Obviously ragtop has a geometry/component issue. Hopefully degreeing in this instance would solve problem or help identify issue. Hopefully badsport is on to something and it is something easily corrected for you ragtop. If you go the degree route it is a PITA especially the first time but take your time & here is one great info. video among several on the web plus the great members here are always available. Keep us posted.
[ame="http://www.youtube.com/watch?v=S7ZzYaMVi00&feature=player_embedded"]ProCharger, Turbo How to Degree Your Cam by Steve Morris - YouTube[/ame]
 
4spdragtop said:
Ok well I think we fingered out the problem, but wont know for a couple days, we gotta replace 2 bent push rods then re-check it......
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C'MON Steve don't keep us holdin' our breath like this
 
On break from work, so when I get home after, I will post more info and pics. All I can say is that I am a dumbass :violent1: So take a guess guys, I think I did something wrong, what could it be???
 
Ok, so after talking to "badsport" last nite and shootin the chit for a while, Bruce came up with an idea. But I had to get in touch with dad to find out the answer, well seeing as how it was closer to 11:30 by the time we got off the phone, it was too late to phone dad. So I had to wait until this morning to call him. I ended up phoning and waking him up twice to get his arse outta bed!! He told me he had started to disassemble, so over the phone it was impossible to figure it out...do ya get the feeling I am dragging this out yet??? Maybe just trying to bore ya all so you dont realize what a dumbass I am! Anyway get to dads take a look at the crank gear and there is 3 spots that the gear can slide on. One is for advance, another is for retard...and the key word here is retard...and the last one is for normal timing. Well take a look at the pic of the crank gear and guess which way we....or should I say I put it on??? Yep the RETARD position, which when doing that decreases the exhaust valve to piston clearance! But in defense of my "retardedness" I assumed the normal or rectangular "hole" was the correct one....WRONG!! The correct one for standard timing is the one with the rounded bottom hole. But take a look at the pic, the standard timing has the "O" stamped in it, I highlighted the "O" with a black marker. So assuming the "O" is correct, which hole would be the one?? The stampings are placed a good distance away from the keyway. Anyway, the slot to the left of the circle is the right one. But seeing as how Im a dumbass, I bent 2 pushrods, so now we wait until we get new ones on Saturday. Its not fixed yet, but I believe this has solved it. Hopefully will make more progress Saturday.
Thanks Badsport!! Thanks everyone else too, I will keep you posted...oh yeah this time Im leaving the intake off until the valves are set..dunno why I put it on, but this dumbassedness is perpetual....
 
I don't want to be the fly in the ointment, but, I can't believe that just changing the cam timing 4* from straight up will cause valve-to-piston contact like that, unless there's precious little clearance in there in the first place.

*Standing by to be corrected.....*
 
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