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Preparing for a rebuild, need clarification on a few things

E eddieMember
High, its been a while since I have been on here, I have a 71 mach1 , 351c m-designation , 4v, large port closed chamber or quench head, I have rebuilt the motor 2twice now, last time was 15 years ago, the machine shop never balanced the motor and I thought they did, kept vibrating and oil psi would drop, after only 700 miles I pulled it apart and all main bearings were to the copper, machinist said maybe I got bad bearings, he checked the crank and said it was fine, put it back together and the oil psi at start up is like 90psi, then after a half hour it drops to around 20psi, I don't drive the car anymore, it only has about 4,000 miles since last rebuild, I read your discussion about the oiling probs, and now im going to tear it apart again and want to clarify what I need to do as far as oiling system goes, I asked this a while back and i don't remember what the answer was, (old age),,

#1. I want to put a roller cam in it,,, do I need lifter bore bushings and cam restrictors? or just bushings, or just restrictors? this car is just for street, no racing, once in a while ill let her eat...I would like to beat a new mustang if i could once in a while.....

#2. do I still use a high volume oil pump?

#3. anybody have any recommendations for a good street roller cam?

#4. I have an edlebrock 4v intake on it right now, I noticed the intake ports are smaller than the ports on the heads,I called edelebrock and I was told this was on purpose to increase volume, should I keep this intake or look for a different one? my car has factory (functional) ram air so the intake needs to fit under the hood.

#5. If the crank is bad (cant be turned anymore) I might look into a scat stroker kit, not sure though, the crank was 10/10 and the block is not even 30 over yet, so not sure if I want to bore it if I don't need to (kit comes with 30 over pistons).

#6. I found you guys are the best to talk to about the 351c, nobody knows anything about it where I live, and I really appreciate your help!!, IM still looking for a pantera to buy, that's near me, but I have to make the Mach1 right, my dad bought the car bran new in 71, hes only 1.5 years away from being 70, want to finish it for him..
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bosswrenchbosswrenchMember
The FIRST thing you need to do is find a mechanic that knows more about Clevelands than how to spell it! They are NOT Chevys and that seems to be most of the problem with builders. If there are no shops close by, a few hours drive or mail-order to a competent shop will be cheaper than changing cranks & bearings once a year.

Second, figure out how you'll be using the car; weekend drag racing with some street time will call for a different build than weekend open-track running, or all street, or...?

Third, get the correct flywheel/flex plate and front damper for the engine. Ford stuff interchanges throughout engine families and much of the 351-W stuff is balanced to different specs than the Cleveland. Balancing is an art so find a shop- maybe a race shop- that knows whats required.

Once these three things are done and the car is safe & reliable, you can think about souping the engine up. And engrave this on your wrist: do NOT use high-pressure or high-volume oil pumps in Cleveland builds unless you intend to race professionally with the car. They cause more trouble than they fix. As for boring the block, if you get to the point where you need another 100 horsepower at lower revs with a stroker, I would call SCAT (or Eagle) and tell them you want 010-over pistons; the default for rebuilding worn out junkyard blocks is 030-over but they have other sizes. Good luck.
ausfordausfordMember
quote:
Originally posted by eddie:
all main bearings were to the copper, machinist said maybe I got bad bearings, he checked the crank and said it was fine


#4. I have an edlebrock 4v intake on it right now, I noticed the intake ports are smaller than the ports on the heads,I called edelebrock and I was told this was on purpose to increase volume, should I keep this intake or look for a different one? my car has factory (functional) ram air so the intake needs to fit under the hood.


#5. If the crank is bad (cant be turned anymore) I might look into a scat stroker kit, not sure though, the crank was 10/10 and the block is not even 30 over yet, so not sure if I want to bore it if I don't need to (kit comes with 30 over pistons).




"machinist said maybe I got bad bearings" I agree with Bosswrench, most machine shops and engine rebuilders don't have a clue about Clevelands, the machinists statement is testament to that.



"I have an edlebrock 4v intake on it right now, I noticed the intake ports are smaller than the ports on the heads," This is not a stuff up by Edelbrock as so many seem to think,it was done very deliberately from results of intensive dyno research.
The port mismatch is beneficial and should not be enlarged or interfered with in any way.
I have used that manifold and it is very good. It is old now and there may be other new manifolds around that may produce an increase in performance over that manifold but there is certainly nothing wrong with it and if it fits under your hood and that is a primary concern there is no imperative to change.



"If the crank is bad (cant be turned anymore) I might look into a scat stroker kit, not sure though, the crank was 10/10 and the block is not even 30 over yet, so not sure if I want to bore it if I don't need to (kit comes with 30 over pistons)."

This is something that annoys me with machine shops, they bore everything .030" over whether it needs it or not simply because they are lazy and .030" is enough to clean up any block.

They don't want to get through 5 or 6 cylinders on a v8 block and find the .010" overbore they are attempting is not cleaning up a cylinder and then they have to start again with a .020" over bore.

That is really a function of slack workshop practice and inadequate measurement and job planning on their part.

This may be a common problem on soft as butter Chevy blocks but on nickle iron Cleveland blocks i would say that .010" would clean up even high mileage blocks, so boring them larger prematurely simply shortens the life of the block and gives you thinner cylinder walls unnecessarily.

I've seen Clevelands with 275,000 miles, with no oil pressure, timing chain about ready to fall off and only .003" wear in the bores and even with bearings worn down to the copper, no wear on the crank. Admittedly that was not in a race car but still that's not bad going.

That engine in fact got just a hone in the cylinders, new rings, polished the crank (not reground) new bearings and was put back into service.



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E eddieMember

Thank you all for the info!, to clarify the block is 10 over right now but it only has about 4 thousand miles on the rebuild, I had no idea back when we rebuilt the motor (twice) that the Cleveland had an oiling issue, and thank god I found this site!, I do not have any good machine shop around here , and the good ones are all chevy , and some ford but mostly 351w,,,actually there is only like 2 machine shops here now. The shop that I had the work done at 15 years ago closed, the guy retired, I wish I knew back then what I know now. The motor will just be for street , but I may romp on it once in a while, no real track time at all. I am just confused as to whether it needs both , lifter bore bushings and cam restrictors? if its only for the street? and im going to run a hydraulic roller so im not sure on the cam restrictors ,, im trying to get this stuff right before I find a good shop, have my ducks in a row , so to speak. I called marvin MacAfee (not sure if I spelled his name right) hes a real nice guy , he came out in some 351c builds, magazines,,,MCE is the shop I believe, I had asked him about the lifter bore bushings and stuff and he kinda seemed like it probably didn't need it , but of course tolerances need to be checked 1st, but it seems like a lot of people don't think the oil system needs attention if its not for race, but I have personally seen my engine eat bearings like nobodys business, and the crank, rods and everything wear within tolerances, so it must have a oil issue,,,when we rebuilt the motor we put a comp cam and lifters in it (flat tappet) with one piece push rods, and clevite bearings,and a high volume melling pump, im thinking the lifters and push rods are letting to much oil to the top but im not sure.

Last edited by George P
George PGeorge PAdmin.

#1. Do I need lifter bore bushings and cam restrictors?

Yes - tappet bore bushings with 0.060 orifices, not only fix the lubrication, they hot rod the lubrication. This is in terms of supplying oil to the reciprocating assembly. Two other steps include:

(1) Augment the factory oil pan with a windage tray
(2) Install the Q code oil pump pick-up.

Those steps supply all the oil possible to the main bearings. Once you've accomplished that you still have to take additional measures to get that oil to the rod bearings. Those additional measures include:

(1) Heavy duty, fully grooved main bearings with performance clearances. Bearings: Clevite #MS1010HG or #MS1010VG. Clearances:0.0025 – 0.0032
(2) Use Valvoline VR1 10W30 oil, no thinner viscosity (due to the fully grooved brgs).
(3) Heavy duty rod bearings with performance clearances. Bearings for 351C rods: Clevite #CB927. Clearances: 0.0022 – 0.0028.
(4) Rod side gap clearances set at 0.018 to 0.022.

I consider cam bearing restrictors a necessity only if you plan on a rev limit higher than 6200 rpm. I consider them a good idea but not a necessity up to 6200 rpm. The most important cam bearing to restrict is number 1.

But Warning. If you install a cam with more lift than 0.530 valve lift the peak horsepower will occur above 6200 rpm, i.e. above the rev limit.  That is the nature of 4V heads. A 4V engine project becomes more expensive above 0.530 lift (about 410 horsepower).

#2. Do I still use a high volume oil pump?

Not if you install tappet bore bushings.

#3. Anybody have any recommendations for a good street roller cam?

The Crane HR216, but it has more than 0.530 lift. I can spec a bit better cam with lift limited to 0.530. About 410 horsepower verses 440 horsepower with the HR216 cam.

Roller cams are also expensive $$$. I can spec an equally durable and strong running flat tappet cam for you that would be easier on the budget.

#4. I have an edlebrock 4v intake on it right now ...

Its OK.

#5. If the crank is bad (cant be turned anymore) I might look into a scat stroker kit, not sure though, the crank was 10/10 and the block is not even 30 over yet, so not sure if I want to bore it if I don't need to (kit comes with 30 over pistons).

Used oem cranks can be found on eBay for reasonable prices, they are way cheaper than a stroker kit.  When any crank is machined make sure to check the quality of that machine work for taper and roundness.

When the journals of a nodular iron crank (like the oem crank) are ground they must be ground with the crank turning in a specific direction, the crank MUST be polished afterwards, again with the crank and polishing equipment turning in very specific directions. If this isn't done correctly the grain of the nodular iron will be "raised" rather than "laid down" and it will abrade the bearings as the crankshaft turns; that is almost certainly why the bearings wore so quickly after the last rebuild. It was the machinist's fault, not the fault of bad bearings.

If you're going to get serious about a stroker crank, limit it to 3.75 stroke, 6.00 length rods, and custom pistons with full round skirts and 1.32 pin height. Spend the extra money having the assembly spin balanced (dynamic balancing).

If you're going to install rods with floating pins the cylinders should be re-bored and indexed to the crankshaft journals. This will prevent the possibility of the wrist pins hammering out their locks and gouging a cylinder wall.

#6. I have to make the Mach1 right, my dad bought the car brand new in 71, hes only 1.5 years away from being 70, want to finish it for him.

Well get with it!

Last edited by George P

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