I have been watching for a low mile roller 302, and finally saw one in a 73 mustang that looked like a rebuild. It was easy to identify as the intake was gone. Also, there wasnt 5 hours of junk to remove from it, and it was front sump. The timing cover was not set up for a mechanical fuel pump though. So, it turned over nicely, and after pulling the heads, I could still see crosshatches in the cylinders and there was no ridge whatsoever. It was also a E7TE block, as I have read that pre 85 blocks may be thinner? One of the pistons had a valve dent? I pitched the heads, as they were D8 heads with giant chambers and giant obstructions in the exhaust ports. The headbolts were not very tight, I would say about 40 ft pounds. I think whoever assembled this thing was very un-methodical. I want to get it into my workspace after I get a engine stand and hoist and get a real close look at it. At this point I am hoping to use it without any machining, but I want to see what the timing chain looks like, see if the oil pump is factory or replacement, and try to ID the cam. The pistons appear to come about .008 to .010 out of the hole, I need to get an exact measurement. Besides the dent, what can anyone tell me about these pistons? I dont see .030 stamped on them....I thought over bore pistons were marked in some way. Is this considered a flat top piston? The circular relief is fairly shallow. Also, is there anything else I should pay close attention to? I usually dont get inside these things, so I am a little bit into new territory.
Those pistons look like the stock '87(?) pieces. They have no valve reliefs so you're limited what heads/valves will work with them.
I had a '86 5.0 HO with flat tops & I mean flat, no valve reliefs or dish in piston, also had Ford part number. Ran great with Trick Flow stage 1 cam and heads.. I have no idea what those are. I don't see a factory piston out of the hole to the extent as these & all '87 up HO motors I've seen had had valve reliefs. Could maybe be a replacement piston for the '86-'91 non-HO? Like '86 HO, those motors used the E6SE heads with flat tops. The non-HO engines used the std 15426378 firing order. Roller it over and check valve action to determine firing order.
I've seen a couple 5.0's with pistons up to .005" out of the hole. The "T" in E7TE means this was originally designed as a low compression truck engine. I believe later on the factory used them in cars too with better heads and cam (and valve relief pistons as Crazy mentioned). Early on the trucks had roller cam blocks but with flat tappet cams installed. I don't remember when the trucks got roller cams, I'm sure you could Google it. Do you have a bore gauge to measure the cylinders? As far as the cross hatch in the cylinders go, I have two 5.0 blocks in storage that both still have the cross hatch. One has 150,000 miles on it and the other 120,000 miles. The cylinders in each measure 4.001" diameter, so only .001" wear. The 5.0 low tension piston rings and more precise fuel metering of EFI account for that.
This is the current firing order. I also put the back of a hacksaw blade across #1 when out of hole and a .020 feeler slipped between it and the deck with room to spare, #4 was a snug fit. .020 out of the hole goes against everything I have read. No bore gauge, but my caliper says 4.00 at the top, so stock bore. I had no idea these things were so slow wearing...Although I did read about a fleet mechanic stating EFI doubled the life of an engine. So I likely have a unmodified/original car engine designed for large cc heads and small valves....and a miniature cam. Lol...once I get it on a stand and make a clay impression, how do you measure the impression without ruining it?
I can't see it as a truck motor, those didn't have roller cams till '92. Plus I've never seen one without valve reliefs(all used E7 heads) & also used HO firing order. I doubt it's anything but a non-HO with aftermarket pistons. As evidenced by valve nick in piston, obviously doesn't have enough valve clearance for std heads. The E6SE heads used with flat tops have shorter valves that are recessed into chamber. Trick Flow heads will work as the valves are rotated off center.
I should go back and measure how thick the head gaskets were. I thought there needed to be at least .035 clearance from piston to head? It may have been operating with less. The heads I tossed aside were D8 something, something....with tiny jammed up exhaust ports.
Yeah my orig Comet 302 had a set of those junk D8 heads(actually one D7 & one D8). Compression was so low it'd spin over like the plugs were removed. Most gaskets are around .039 compressed. Other than maybe Trick Flow heads, I can't see those pistons useful for any other performance versions. On exhaust I believe minimum piston to valve clearance is .100 and .080? on intake. Of course lift & duration have a large effect on what actual clearance will be. The flat tops in my '86 HO were approx .003 out of the hole, as I stated were great with TF heads. Spun it as high as 6400.
Well Dayum... The ones I've seen had valve reliefs. Thinking back, none of those had roller cams. No doubt cam lift is .400 or less. You know what's really sad? I made it two days before end of 2019 to screw up a otherwise "perfect" year...
That is an awesome series of videos. I am gonna hunt down anything he does in the rebuild department and check them out later on.
I found the 8 video re-assembly series. I gotta figure out what I can and cant do with this thing, and add up the cost. I may just return it to the junkyard with my "warranty" and trade it for an explorer bottom end. I have to get the pan off and see if I can figure out what, if anything, has ever been done to this motor.
Head gaskets were victor reinz, and measured .055 thick (.035 squish). The intake valves looked very close to deck level. I need to go back and measure with a feeler gauge for my own info. I need to mock this up with my GT 40 heads just to see what the PTV clearance is with current cam. Would be nice to see enough clearance to put in more cam, but I wont hold my breath.
A cam's duration has the biggest affect on piston-to-valve clearance. You might be able to go with higher lift but keep the duration moderate. It'll raise your dynamic compression, too.
