rich allen

Hi all. Its been a long winter, and its snowing as I write this, but, who cares. Spring is coming. Was wondering if you can help with this. I popped my motor a couple seasons ago, and had it rebuilt, slightly warmed over for some more snot. The shop is reputable, and the motor runs fine. I had some family health issues and a house re-model that kept me busy the last two summers. ( I did manage to finally get that 40ft deep garage bay added that I wanted so badly). Now its back to the water. I wanted to get some opinions, and also some info if someone can help. I was trying to figure out what the compression ratio of my setup currently is. Maybe someone has a formula handy. The engine is originally just a 330 hp 454, bored .030 over, and decked .010 as well. The pistons are forged trw's, with .226 domes. I am running a comp cam,# 11-306-4, with .222 and .226 @ .050. Intake is a performer rpm, and carb is also edelbrock 750 marine. Exhaust is EMI thunders. The heads are the week link, and are stock peanut port heads. I am trying to figure out what compression ratio is right now, but when I started to try to find what the current quench was, I did not know,or what cc those heads typically cc'd at. Can someone get me close? Also, wanting to know which heads would work best with what I now have, and where they would put my compression at. Sorry so long, and thanks for any help.

dyno

I think your going to need to know how they cc.... to get compression ratio. but if you didn't change the pistons(go to a dome) just bored it oversized your close to stock at 8.7 or so.....

formula31

The peanut ports I have all measured were very close to 119 cc. most of the trw forged piston are .025 down in the hole so you are are likely down .015 now. with a .035 head gasket you would have a quench of .050, not ideal but ok. That piston looks like a L2465F which would give you a ratio of 9.6-1, a little high for marina fuel but ok on 91 octane with the timing at 34 max. It sounds like you could use any of the good aftermarket heads or even a good set of large oval ports done right as long as you stay 119 cc or bigger. If you can find a good set of Merlin oval ports would be your best bet for my .02$.

rich allen

Aloha from Western Ma.. Granby specifically, but if you know where Amherst, U-Mass area is you are pretty close.

rich allen

Good info, thanks.. Yes, you are correct, they are L2465f pistons. I too was looking at the merlins. Do you think the carb is sufficient size for this application?

rich allen

Boy you are right. However, your intervention must have gone well. You seem to be functioning quite well in spite of that place.

formula31

I never had any luck getting top end out of the Quads but others swear by them. 750 cfm is fine for what we have, I just know the holleys better.

rich allen

4 years later, this thread is unfortunately back to the top.
Had a great 4 seasons with the motor combo described here previously. But noticed I was losing some power as of late. And recently lost even more, to the point of not running right.
Long story short, lost compression in two cylinders. #3 and # 4 specifically. Pulled the heads last night, and both intake valves are mushroomed, or concave to describe it. Looks as if the were forced into head until they began to curl on the edges, until no longer seating properly. Is this typical of hydraulic lock, or is this valve fatigue. No other signs of distress, and pistons and bores are fine. One piston has minor imprint on dome where edge of intake valve kissed. Again, wondering if this is from valve stretching to the point of contact. I actually see that a third intake vave is showing some daylight from behind as well (flashlight) but not as bad yet as the others. I don't really see any signs of water intrusion, but I could be wrong. I am running a semi-mild cam, as you can see from earlier post, and really never thought I was getting any reversion. Perhaps my riser gaskets are leaking now?
Any insight would be a plus at this point. My plan is to purchase a set of heads already built, and be done with it, in orde to salvage the summer. But would also appreciate some input for these as well from member experiences. It appears I currently have about 9.6: 1 comp. with current set up. Don't wish to go any higher, but now is my chance to upgrade from these stock peanut heads to get some better airflow. (within budget of course)
Thanks guys...

800XCR

iTrader: (2)

Caused by excessive heat - typically associated with detonation and or a severe lean condition and called tulipping.

redcorvetteman3

Yep like he said and add in sea pump break down and water circleation