Blew my LS1. Threw my stuff in an iron 5.3 with milled 706 heads, 7.4 pushrods, and a 231/237 .598 .595 112+2 lsa Cam.

It is appearing to bind up when the valves open all the way. Is it too big? I am not an engine guru and I am taking it to the guy who assembled it tomorrow to check some things. Could it just be the pushrods are too long since the heads were milled or do yall think that the valves are hitting the pistons, and I'd need a smaller cam?

I do not know how much they were milled atm, but should have more info tomorrow. Also do not know what head gasket he put on but it looks the same size as stock. Just wanted to get a quick questionnaire out to yall to see what you think.

 

If it's binding near max lift, that is likely not PTV. maximum valve lift is normally close to BDC on the piston. If it is definitely binding at max lift, I would check the springs first to see if they can handle the lift. Depending on how much the heads are milled, the pushrods could be a bit long, adding to the valve lift.

If you think the valves are hitting the pistons, that would have more to do with the cam timing than anything. While he is looking at it, you might want to make sure the cam is degreed properly. More than likely, you are not getting PTV contact.

I do think that cam's duration is too big for a 5.3, regardless of the other issues, and will probably drive very poorly below 3500 rpm.

 

That's a healthy sized cam for even an LQ9 6.0 liter
I'd put a Texas Speed 220R in there for the 5.3 to be a snappy little runner

 

I'd seriously rethink that cam choice, with those anemic heads and small displacement i dont see that motor making power or driving well at all

 

its got springs rated to .650. its all the stuff that was in my ls1 just moved over outside of the heads, since the 241s dont make good power with the 5.3...

If I have to ill put a different cam in it, but id rather not, trying to do this on a budget... but as I have learned even with this 5.3... there is no such thing as budget

I always thought with the LS motors you could swap stuff around without issues, im finding thats not the case as much

 

You'll hate that cam till you get to 5000 rpm or so..... bet it'll feel sluggish down low.

 

Well it's going back into the Fbody, So I want something with some pep and attitude. I am not trying to have a sleeper cam, I want to have it run nice, so the 220r seems too mild for me. I may have to call TSP tomorrow

 

This cam/motor would be a placeholder to hold me over until I can build the car the way I want to honestly. If it drives, and sounds good, and can hold its own against a mustang I am ok for now really. I just want it driving again, and the wife damn near kicked my *** when I told her I may need a ~$400 cam...


EDIT: car would have whats in my sig.

 

So you asked if the cam was too big, and three very sharp, knowledgeable
and experienced members have told you for a 5.3 that cam is too Big!
It's on the large size for a 5.7, and as has been stated will run very poorly
Till 3500-4000 RPM. 220* will run much better!

 

I am going to be getting a new cam then. I will talk to TSP tomorrow about it. Thanks guys, I really appreciate the answers!

 

If your cam is still in good shape, sell it for a couple hundred bucks and search the classifieds for a good used 218/220 or at most 224 duration cam. Yes you are right, those are all mild, however keep in mind that they are about THIRTY degrees at .050" more than a stock 5.3 cam.

 

Yea I will sell this one and probably go with the 224 cam from TSP. 220 is way too mild i do not want a stock sounding car. I want my rumble back and my power!! It is not in the slightest a daily driver so its not that big of a deal. Maybe 5k miles a year if I am lucky.

 

224 or even the 228 would do well.

 

Your sig has 400 RWHP. If you want that much power out of a 5.3 pretty much on demand, you might want to consider going FI. The 5.3 just won't have the bore, and the 706 heads flow like stir-fried crap.

I think a 224 is a good choice for good thump and decent power.

 

He was asking if the size of the cam is what is keeping the engine from turning over. I didn't see where he was asking for performance opinions.

 

What are you guys talking about? It will be fine with 4:56 gears

On a serious note, I would highly recommend getting a milder cam

 

Ya sorry to say you're going to be really dissapointed with the power of that 5.3 over your ls1. Why not try to find a 6.0 shortblock? They arent terribly expensive

 

Truth! If your sticking with the 5.3, I'd force feed it.

 

That cam would be very well matched to a 6.0. That's a good call

 

exactly 400 to tsp is 400 towards a 6.0 that can usually be found for under 1k. slap the ls1 heads on it to bump up compression and call it a day