I check the rollers for chipped edges and smooth operation, then disassemble and clean with spray carb cleaner and paper towels. They often get gunked up inside.
I soaked the lifters for a day in 50:50 mix of ATF and acetone but couldn't get them apart. Too much hard carbon deposits built up on the inside. $100 lifters arrived today from Summit. Had a $20 gift certificate from the headers pruchase so I'm good with that. Magnaflux report on the block was good so I ordered the re-ring kit from PAW. Rings, bearings and FelPro gaskets for $177.
I wonder why your machinist recommended cast iron rings? They take longer to seat than the moly-faced rings that are used mostly nowadays.
Better check your facts, moly-faced rings seal almost as soon as the engine starts, cast iron takes several hundred miles of alternately flooding and starving the rings with oil to seat because it's a harder material. And there's no reason that his cylinders shouldn't have a good cross hatch, bore diameter has nothing to do with honing accuracy. I've had plenty of moly-faced rings seat just fine from just using a bottle brush hone, no Sunnen required.
CR is strictly a physical measurement of unswept/swept cylinder volume and can't be determined by cylinder cranking pressure. Cam specs, especially IVC point, have a big effect on cylinder pressure but doesn't change a cylinder's mechanical compression ratio. If one cam closes the intake valve earlier than another cam and allows the pressure to start building earlier, that cam will generally produce a higher cranking pressure than the late-closing cam. As an example, my current motor previously had a roller cam with almost 300* advertised duration, cranking pressure was around 165 psi in all cylinders. Installed a new roller cam with 266* advertised duration, cranking pressure in every cylinder increased by 15 psi to 180. The compression ratio (unswept/swept cylinder volume) remained unchanged. Even day-to-day barometric pressure differences can slightly affect cylinder pressure readings.
Good info. Makes sense. Here's what Wikipedia says: "In a piston engine it is the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, and the volume of the combustion chamber when the piston is at the top of its stroke." In my case: Volume of each E7 combustion chamber: about 64cc = 3.9 cubic inch + .1 for slight dish in nearly-flat pistons ~ 4.0 cubic inches. E8 pistons reach the deck. Volume of 8 combustion chambers: 32 cubic inches Volume of 8 cylinders: 302 cubic inches Then, I guess the CR is approximately (302 + 32)/32 = 334/32 ~ 10.4 Could that be right? Man, I hope the valves have some clearance. Might need 93 octane?
The only way to know for sure is to actually measure the chambers, measure the piston tops, measure how far in the hole the pistons are, and account for the thickness of your intended head gasket. Usually the actual measured compression ratio is not as high as you guesstimate. Here's a calculator I like to use: http://www.fordmuscle.com/calculators/compression.php
Oh yeah, forgot about the gasket. Figured I was missing something. I'll take some measurements when its assembled but, assuming .047 for the head gasket, I'm estimating something more like the stock 9.2:1. Thanks for the help.:Handshake
Geeze, no need to get personal. I guess we could go back and forth forever and a day on this subject as I can find just as many instances to support my view. From the professional engine builders on SpeedTalk: http://www.speedtalk.com/forum/viewtopic.php?t=10808 “Very little seating goes on with moly rings ... pretty much seated when they start.” http://www.speedtalk.com/forum/viewtopic.php?t=5647 “All I can tell you is I have used the 400 for "plateau" for years now … …The rings are seated about the time it starts “ When I made my post I was speaking from personal experience, not some internet BS. I have built quite a few engines in the past 35 years, the last 6 or 7 I’ve used moly-faced rings. They have all seated almost immediately after about 8 – 10 strokes in each direction with a 400 grit ball hone followed with a nylon brush. This was on top of the 280 grit hone performed by the machine shop. I have never seen cast iron rings seat as quickly. A couple of your referenced articles seem to be outdated, they mention moly-filled rings. Those were rings with a channel on the ring face and a solid band of moly material inserted. They were known for the moly material flaking off and causing sealing problems. I don’t even know if you can still buy them, all I see nowadays is moly-sprayed rings that have the moly applied by a plasma spray process. No chipping occurs with these because the film is very thin. After my original post, and before yours, I did find some good information on why the original poster’s machinist recommended cast iron rings. Has to do with the amount they can deform and wear into a less than perfectly round bore.
Valves Clear!! Got the heads ported and valves lapped and reassembled. But, is there any valve clearance? '86 HO (near) flat top pistions with zero combustion height and no valve reliefs. E7 heads with .005" removed for resurface. Installed the old, compressed, .047" head gasket and two of the old lifters with their pistons frozen in the full up position. Put some putty on top of the piston and bolted the head down. Turned the crank carefully and got the result shown in the pictures. The thickness of the putty between the flat part of the combustion chamber and the pistion should be the thickness of the head gasket, .047". Valve clearance looks the same. Should be good, right?
No, I didn't till you asked. The edge of the clay was close to the max depression from the valve and it looked like the same thickness as under the flat part of the compustion chamber. However, your question made me go back and look a little more carefully. The picture is the cross section of the clay showing the max depression made by the valve with the least clearance. Not sure you'll be able to see it in the picture, but the thickness of the clay under the valve is very slightly more than the thickness (.047") under the flat part of the chamber.
I have heard of people running less clearance, but I like to have at least .080" on the intake and .100" on the exhaust vertically, .060" radially on both valves. If the piston-to-deck clearances for the cylinders aren't all the same you need to find the highest piston at TDC and perform your check there. If you're actually at .047" or so, that's pretty tight, metal grows and clearances tighten when up to operating temperature. Do you have a caliper or mic to measure accurrately?
I have mics but not sure I can get the putty off the plate without distorting it. When I can find my feeler gauges I'll stack some up beside the clay and get a more accurate measurement. To press the clay, I used old lifters with their pistons frozen in the full up postion. Had the lifters not be frozen up, they would have compressed some when I bolted the rockers down. So I'm thinking the valves are being raised a little more than they will be with working hydraulic lifters. I suppose that high RPMs might stretch things a little and reduce clearances but I won't be reving very hign. Probably never above 5K. Don't plan on floating the valves. Thanks much for all the info. Its great to get advice from guys who have done it lots of times before,. I appreciate you and the others taking the time to do all the replys.
Thats not enough clearance...Sorry... As Barry stated... You want at least .080 on the intake and .100 on the exhaust at a minimum.Valve float and lift figures, along with inconsitency in valve train components and reciprocating parts with .047 valve clearance is going to get the valves and pistons very cozy once it all warms up.Oh dont forget those forged pistons.They grow more than cast ones do as they heat up. All is not lost...You can fly cut them your self.I forget who manufacures the tool but,its simple to do.
