Engine clearance specs

[pivichot]

Some may know that the 5.0 for the Mercury is almost built. I just have a few questions. This is my first build and I feel confident that I can build the engine. I have a dial bore gauge that is accurate to 0.0001'', and calipers that are accurate to 0.0001''. Is there a book that is suggested to get correct clearances? I just need the following clearances.
rod bearing clearance
crankshaft bearing clearance
connecting rod torque specs

Also, do you guys suggest to reuse crankshaft bolts or just buy new bolts to be on the safe side?

Last thing. What is the spec for the acceptable size for crankshaft journal and where the connecting rod journal on the crank?



Slow and steady.
Also the gt40p heads are at the machine shop. Do you guys think I should upgrade to roller rockers?

[Grand Marquis GT]

Replace the bolts. I like the ARP fasteners myself.

[magnus77]

Not sure about clearances but I would definitely not risk using old bolts: they're cheap and and it would be good insurance. Also roller rockers are always a plus if you can afford them, they provide cooler oil temps and less frictional loss.

[pivichot]

Ok. So I will buy new arp fasteners for the block main and I'll see if the budget permits for roller rockers. Since I have gt40p heads, are there any specific roller rockers that you guys suggest? 1.6 rockers.

[magnus77]

Uh, I have 1.7 RR crane rockers myself that I'm planning to put on this summer, theyll add a tad extra lift to my lopo cam - but I think any well known brand should work. You want pedestal mount rockers for the gt40p's if you didnt know that already.
You could look into crane, scorpion, comp, trick flow, some people use harland, i would avoid proform, and for a budget summit racing brand might work but I'm not familiar with any reviews on them.

[pivichot]

Uh, I have 1.7 RR crane rockers myself that I'm planning to put on this summer, theyll add a tad extra lift to my lopo cam - but I think any well known brand should work. You want pedestal mount rockers for the gt40p's if you didnt know that already.
You could look into crane, scorpion, comp, trick flow, some people use harland, i would avoid proform, and for a budget summit racing brand might work but I'm not familiar with any reviews on them.

That is what I didnt know about the pedestal mount.. Thank you.

[gadget73]

I've re-used the stock rotating assembly bolts on mine twice now. That engine has a combined total of right near 200k miles on it, with two rebuilds. It hasn't let go yet. Better bolts aren't a bad idea, but its not like they are going to asplode if you don't. The head bolts go in the trash though, the stock ones can fail without being dicked with, they are not worth trying to recycle.


I'll try to scan you the specs page out of my 91 Mark VII manual. It has all of the data you seek.


Skip the cheap Crane rockers. They don't last super amazingly well. They're basically the same as the old Cobra rockers, which some people including myself have had issues with. Oddly it wasn't the aluminum that gave on mine, the steel pivot shaft didn't seem to be properly hardened and the needle bearings caused them to wear out. The Scorpion set I put on there seems more solidly made. If nothing else, I had them and swapping them cost me nothing. Some roller rockers will hit stock valve covers, so be aware of that too. The boring lopo stamped covers actually have a lot of room under them, so if you've got them they may work for you. I have 85 Mustang covers, the old finny aluminum Power By Ford ones, and they clear my Scorpion 1.72's with no modifications.

Check your lifter preload too, I needed longer pushrods. Need a dial indicator for that. A cheapie 0-1" x 0.001" will do it just fine. Shars and various other China vendors sell them for under 20 bucks a pop all day long.

[pivichot]

I've re-used the stock rotating assembly bolts on mine twice now. That engine has a combined total of right near 200k miles on it, with two rebuilds. It hasn't let go yet. Better bolts aren't a bad idea, but its not like they are going to asplode if you don't. The head bolts go in the trash though, the stock ones can fail without being dicked with, they are not worth trying to recycle.


I'll try to scan you the specs page out of my 91 Mark VII manual. It has all of the data you seek.


Skip the cheap Crane rockers. They don't last super amazingly well. They're basically the same as the old Cobra rockers, which some people including myself have had issues with. Oddly it wasn't the aluminum that gave on mine, the steel pivot shaft didn't seem to be properly hardened and the needle bearings caused them to wear out. The Scorpion set I put on there seems more solidly made. If nothing else, I had them and swapping them cost me nothing. Some roller rockers will hit stock valve covers, so be aware of that too. The boring lopo stamped covers actually have a lot of room under them, so if you've got them they may work for you. I have 85 Mustang covers, the old finny aluminum Power By Ford ones, and they clear my Scorpion 1.72's with no modifications.

Check your lifter preload too, I needed longer pushrods. Need a dial indicator for that. A cheapie 0-1" x 0.001" will do it just fine. Shars and various other China vendors sell them for under 20 bucks a pop all day long.

Ok. Thanks gadget. I have explorer valve covers, I will be careful with the roller rockers then. I was thinking about scorpion rockers. I have a dial indicator so that wont' be a problem. Just one question I don't need to remove material then for the pedestal mounted rockers? Some people on mustang board are saying you have to remove 0.2'' from where the rockers mount or something along those lines.

[gadget73]

I didn't remove anything, but I suppose you could shave the pedestals rather than going for longer pushrods. You don't need a milling machine and setup time to change pushrods. The stock rods are not exactly anything special anyway. One thing they are though is dead nuts consistant. I measured mine, plus some others I had hanging around and between 25 or so of them, I got 0.001" variance. The aftermarket CompCams set gave me something about .007" out of the set of 16. Some of my rockers have no shims, some have the thin shim, some have the thick shim. I did them valve by valve to get it all where it belongs, and the engine is quieter than it has ever been now. Some of that variance is probably valve stem wear, some is likely tolerance in the rockers, some is the pushrods, and some may be wear or damage to the surface they bolt down to on the head. Won't swear to it, but the dial indicator will tell you what needs doing. I want to say its .020 to .060, I just tried to land mine as close to the middle of that as possible to minimize any issues with measurement problems or anything else.

Forgot to take the book with me. I'll put it in the truck now so I can scan it tomorrow.

[pivichot]

I didn't remove anything, but I suppose you could shave the pedestals rather than going for longer pushrods. You don't need a milling machine and setup time to change pushrods. The stock rods are not exactly anything special anyway. One thing they are though is dead nuts consistant. I measured mine, plus some others I had hanging around and between 25 or so of them, I got 0.001" variance. The aftermarket CompCams set gave me something about .007" out of the set of 16. Some of my rockers have no shims, some have the thin shim, some have the thick shim. I did them valve by valve to get it all where it belongs, and the engine is quieter than it has ever been now. Some of that variance is probably valve stem wear, some is likely tolerance in the rockers, some is the pushrods, and some may be wear or damage to the surface they bolt down to on the head. Won't swear to it, but the dial indicator will tell you what needs doing. I want to say its .020 to .060, I just tried to land mine as close to the middle of that as possible to minimize any issues with measurement problems or anything else.

Forgot to take the book with me. I'll put it in the truck now so I can scan it tomorrow.

Okay no problem. I will keep that in mind when setting up the rockers. Good thing then if I don't need to remove material, I'll just buy in case a pushrod length checker.

[gadget73]

yeah, do that. I made my own and thought that I could simply measure it with a set of 8" calipers. Comp pushrod measurements are not a number you can actually derive with any measuring device you will ever own. Their pushrod length checker will apparently spit out a number that matches up to what you need to order. I think what they do is to give a number from center to center of each spherical end. The sphere isn't easily measured because the end is lopped off, and its not like the stock rods where its basically a ball welded to a tube. If you knew what the diameter of the sphere was, you could arrive at their number by doing some measurements and then tacking in some math and hoping that its right.

Much easier to just use their tool and call them with what it tells you.

Stock Ford pushrods are easy, measure end to end with a caliper and thats how long they are.

[gadget73]

See if this comes through clear enough to read. If not, PM me your email address and I'll send the higher res scan.

[pivichot]

See if this comes through clear enough to read. If not, PM me your email address and I'll send the higher res scan.

[ATTACH=CONFIG]45708[/ATTACH]

[ATTACH=CONFIG]45709[/ATTACH]

Everything Is perfect to Read. Thank You Gadget.

[pivichot]

Ok. So I bought ARP bolts for the block. But the instruction says it has to be line bored. Debating whether to upgrade then to studs or find factory bolts. Where would one find factory style bolts? Or should I just bite the bill and just upgrade to the bolts or studs? Money is a little tight, but rather do this the right way. I have a dial bore to measure the mains of the block with the factory bolts and then with the ARP bolts. Any suggestions appreciated.

[gadget73]

Don't frankly know why one fastener would require line boring and another would not. It should not distort the block to change from a bolt to a stud or from one type bolt to another. The main caps locate by dowels if I remember correctly. If its not dowels, its some other means that doesn't relate to the bolts. The bolts only keep it clamped together.

For whatever it may or may not be worth, my engine has factory hardware throughout, and it has not blown itself apart. The stock bolts are typically stronger than the cast iron around them is anyway.