LSXSeven

iTrader: (1)

Ok I have been searching and learning as much as I can. I need a little help however with these last two issues as the formulas are a little complicated and I really do not want to screw something up.

1) stock bottom end 3.90 bore
2) 243 heads milled .020 with 2.5 int and 1.6 exh
3) cometic head gasket either .040 or .045 you decide
4) 64.6cc chamber on one head and 64cc on the other(that was written there by the company that did the head work
5) double springs not sure brand (used heads)
6) jeselshaft mount rockers 1.7 ratio nonsdjustable
7) comp cams XEr grind 3726r/3728r 114+4
base circle ?
duration at .050 232/236
duration at .006 281/285
valve lift .595/.601
lsa 114+4
ICL 110
Intake open 6* BTDC
Exhaust close 0* TDC
8) LS7 race lifters

Will I need to flycut? what is my SCR and DCR? How is my PTV clearance.?

That is about it for now

Thanks
Mike

8banger

iTrader: (16)

That kind of mill with those gaskets, and the bigger valves.... no way. You can't really fit any cam with that. You're taking away .060" clearance and adding bigger valves...won't work.

LSXSeven

iTrader: (1)

How did you come up with the .060 figure. The heads have been milled .020 and the gasket will either be .010 thinner(.045) or .015 thinner(.040). This is assuming stock MLS gasket at .055. From what I've read .054 but whats .001

Add those together and you get max .035. What am I missing here?

Mike

Irocss85

iTrader: (1)

thats what I was thinking exactly.

LSXSeven

iTrader: (1)

any other input?

8banger

iTrader: (16)

Wow...it was only 10:30 and I made that little sense? I had a dinner 'meeting' with my office people and had a few drinks...a few that were a bit too brutal and tasted like gasoline, so I wasn't thinking right. I see what I did, I added the .040" gasket thickness to the .020" mill. I'm dumb. I'd still worry about the thinner gasket and the bore because of the bigger valves. Taking into account that I'm dumb, I think it might fit. Patrick G would know.

LSXSeven

iTrader: (1)

how does this look. Is this correct. I am unsure of some of the data figures.

8banger

iTrader: (16)

Looks good to me.

LSXSeven

iTrader: (1)

anyone want to take a stab at the flycut issue with this setup?

N4cer

iTrader: (11)

Probably won't have to but why chance it? It's cheap, easy, and fast. No reason whatsoever to not flycut.

LSXSeven

iTrader: (1)

Well we started to flycut yesterday. I borrowed the isky tool and a cut off section of a head that is used to set everything up. The 1st cut we did was very shallow just to test everything. We raised the collar and cut some more. Again a little deeper. Raised the collar some more and went to make the final cut, now the tool won't finish cutting to the new depth. Took it appart to check it and found nothing wrong. Put it back on and now the new cut is off a slight bit from the old cut. There is a slight double lip. Moved it to another piston and it cut about 3/4 of the way down but wo't cut any further. If we back the piston down a little the tool drops all the way to the collar so it's not binding. What gives? Could the tool be dull? Has anyone ever had to get these sharpened? What should have been an easy process has turned into a pain in the ***.

Mike

N4cer

iTrader: (11)

My Isky tool made it just fine through 8 piston cuts of .070" depth. Are you sure you measured properly when setting the collar? The tool cuts very quickly. I can't see you dulling it on one single motor. Make sure to cut in the proper direction. We made the mistake of reversing the drill and it unscrewed the tool from its insert.

LSXSeven

iTrader: (1)

We did accidentally run the drill in reverse at one point but I can't see that running the bit. If you look at the shape of the edges it can be run in either direction. One side will cut and the other side just makes a pass. I imagine this is so it will cut on either side and when doing valves layed at the opposite direction. I am affraid to move the collar as this does not seem to be the proble. It just won't cut deep enough now to run the collar all the way flush. Id did when we made the 1st small cuts but not now. With my luck if a raise the collar some more it will all of a sudden work and go too far

Also, I had found a link to the instructions the other night but can't find them again. Linky please

Mike

LSXSeven

iTrader: (1)

Also I borrowed the tool from the guy who is going to tune the car.I do not know how many times it has been used without sharpening. I really cant see how the soft pistons could bea match for the tool. We did not try the exhaust side yet. Maybe the other head will work better.

Mike

N4cer

iTrader: (11)

First off, have you measured your cam and heads? I ask because I'm shocked that the exhaust will need flycut.
How deep do you plan to cut the exhaust side?
And how deep are you needing to cut the intake side? I ask because like I said, we only went .070".

I'm not sure what instructions you're talking about. We blueprinted the motor and then cut what was needed. Pretty simple. Tool on head. Head on car. Drill on tool. Pull trigger. But if you find instructions let me know. I'm interested to see what we might've done wrong. Oh yeah... we had the advantage of the motor being on a motor stand. Despite what you hear on here, it's very simple to pull the motor from the top. VERY simple.

LSXSeven

iTrader: (1)

My motor is on a stand as well. This should be a no brainer. I am only cutting .075. I have not done the exhaust. The shop that sells this cam and heads, recomends flycutting. I figured .075 wouldn't hurt. He loaned me the tool and a section of head that covers one piston at a time. Since it only uses 4 bolts and does not lock onto a dowl ecept for the last cylinder there is some up and down play. I am not to sure about that. I am going to find a way to secure it in the exact spot before I cut anymore. I have only done one and a half. The bit just won't cut down to far enough to get to .075.

Mike

LSXSeven

iTrader: (1)

I am also calculating my pushod length. I plan on checking it assembled with a pusrod checker but for now, here is what I have.

Comp cams XER base circle is:
Intake = 1.457
Exhaust = 1.445

Stock cam = 1.556 int and exh

this means a shorter base circle on intake of .0495 and exh. of .0555.
(1.556/2)-(1.457/2)=.0495 and (1.556/2)-(1.445/2)=.0555

This would require a new pushrod length of 7.450 if no ther changes

But, since my heads are milled .020 and the new gasket is .015 thinner, I get .035 back. This now leaves me only .015 short on my pushrods.

So if using the new LS7 race lifters, should I use the stock pushrods of 7.4 or get new 7.425's. One will give me slightly less preload and the other will give me slightly more but cost money. This all assumes that actual measurements confirm these numbers

Mike