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351 C Engine rebuild. Not an expert, want some solid advice.


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So I need to build a new engine.  I have the original, 110k mile old 351 C 2 bolt main block, and period correct 4V quench heads and cast intake.

Dropped the engine at the machine shop today and was surprised  to hear that the minimum bore option was .030 over.  With this being the first tear down of the original engine I was hoping a clean up pass of .005 and some oversized rings would be an option. (My engine that just failed was a .030 over, making me gun shy.)

So since I have to buy crap, what should I buy for a fun, street worthy,, powerful engine.

So I plan to use the standard crank, the quench chamber heads, and whatever I can do for pistons.  I think I would like to go with a Boss 351 grind to the cam, but going with a roller cam and lifter setup, and a double roller timing set.

So, what should I do for pistons and a cam?  Any particular piston head or just  flat tops.  Is .030  over ok for a bore on a Cleveland.  Is there an awesome fun cam grind for a 3:25 rear gear and a 4 speed?  Who should I buy cam through.  The machine shop said they are seeing a long lead time on roller cams.  Should I harvest any internals from the trashed engine, or buy new sets?  Should I have the Machine Shop assemble or buy a stand and torque it all myself?

thanks!

kcmash

 

 

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If you're keeping that rear gearing you are somewhat limited on camshaft selections. You probably wouldn't want to go with more than 285° advertised duration on the intake and around 290° on the exhaust.

Clevelands can handle 0.030" over with no problem.

You can play around with a cam selector in the spreadsheet in this thread, to see what the variables are and what effect they have.

Camshaft Selection - Engine, Transmission, Drive Line, Etc - 7173Mustangs.com

That said, I would go with a 393 or 408 stroker kit from Scat, will come with pistons, rings, crankshaft, rods, bearings, damper, and flex plate. That will give you the power and burn your tires off, even with that rear end. Stroking an engine makes a big increase in torque.

My personal preference is to assemble the engine myself, I like doing it, a lot of personal satisfaction comes with it.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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I agree with Don C, build it yourself. I finished building mine I guess about a year ago and it started and ran great first turn of the key. I kind of wish I would have went with roller rockers but I went with a flat tappet Stage 3 cam and lifters, flat top pistons (30 over), double roller timing chain, rebuilt heads (2V) with hardened seats, standard crank (10 over if memory serves), stock intake (may change that out soon) and Holley carb.  I upgraded from my 289 (I think they were 289) rear gear to a 355 set. Mine should be on the road soon, finishing up the dash install this weekend.  Good luck, if you build the engine yourself, take your time and recheck everything, you will enjoy it more when done.  

Tom

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So I have started doing some research.

First, the selections for roller cams for the 351c seem limited and expensive.  Is it worth the $800 to $1000 to roller, or do I stick with flat tapped?

Based on the responses above, you guys don’t like my 3:25 gear I guess.  Here in Kansas City it seems every event is a 45 minute drive from me, so I don’t mind that gear.  I can still lite em up if I feel like it, but the highway driving is fun.

Also, I cannot get the cam sizing tool to run on my iPad.  Even with office installed.

kcmash

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Kcmash.

Looks like you got some homework to do before you start doing your homework.

1 figure out what octane fuel you intend to use.

2 how are the mating surfaces of the cylinder heads and cylinder block.

if too much material has to be removed to make surfaces true, that MAY influence your piston choice.

3 piston selection. you need to choose carefully, with closed chamber heads and the wrong compression height, or amount of dish will influence your static compression ratio.

4 dynamic compression ratio , after amount of machine work figured and a piston choice is made then you can make a camshaft choice based on the type of fuel you want to choose,  there are calculators out there, once your static compression ratio is determined  that you can input your desired camshaft specifications into and come up with with with a dynamic compression ratio that will make your engine detonation free and long lasting.

Get it wrong and your engine could be a real slug or worse yet a detonation prone failure.

To my experience 8.0 to about 8.2 dynamic compression ratio is about maximum for 91 octane zero ethanol fuel.

Boilermaster

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I had an iPad once, then an Android, now I have a MS Windows tablet, no drama, no proprietary BS, everything works.

My '71 has a 3.73 rear end with a Detroit Locker, a lot of fun, zero to 60, not so much on the highway, which is why it's slated to get an overdrive, probably a Gear Vendors, make the C6 operate like a six speed. I always liked splitting gears. I like the thoughts of a 4R70W and locking torque converter, from Monster, and being able to fine tune it with a Baumann controller, but my C6 can handle my abuse, and like I said I like splitting gears. 

The biggest advantage of the roller lifters is not having to worry about wiping out the lobes on a flat tappet cam. For most driving the flat tappet is just fine, and plenty of choices

This brings up a trivia question. Know why lifters are called tappets? When internal combustion engines were developed they all had solid lifters, and were called tappets because of the noise they made (still do).

As to availability, there actually are a lot of selections, don't forget about about Lunati and Howards, they have good off-the-shelf roller cam selections for Clevelands, and then you can get a custom grind. But you're right, not cheap, especially the lifters.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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10 hours ago, boilermaster said:

Kcmash.

Looks like you got some homework to do before you start doing your homework.

1 figure out what octane fuel you intend to use.

2 how are the mating surfaces of the cylinder heads and cylinder block.

if too much material has to be removed to make surfaces true, that MAY influence your piston choice.

3 piston selection. you need to choose carefully, with closed chamber heads and the wrong compression height, or amount of dish will influence your static compression ratio.

4 dynamic compression ratio , after amount of machine work figured and a piston choice is made then you can make a camshaft choice based on the type of fuel you want to choose,  there are calculators out there, once your static compression ratio is determined  that you can input your desired camshaft specifications into and come up with with with a dynamic compression ratio that will make your engine detonation free and long lasting.

Get it wrong and your engine could be a real slug or worse yet a detonation prone failure.

To my experience 8.0 to about 8.2 dynamic compression ratio is about maximum for 91 octane zero ethanol fuel.

Boilermaster

Thanks for the dialogue.  My biggest problem here Is restoration burnout.  I finally got this SOB on the road, then I lose the engine.

so I don,t know how to state what I am looking for.  Performance somewhere between an M code and a Boss351 will likely be fine for me.  Reliability is important.  I use the BP premium fuel in this car.  The block has never been serviced, this is the first tear down since the car rolled off the line.   
 

so I am thinking this should be a pretty easy build.  I don’t have a Horsepower target,  I don’t have a 1/4 mile target, I just want a little hotter performance than stock.  What are those simple upgrades to the 4 v Cleveland that Ford should have done to make it a little more fun?  Or is fresh M code performance the way to go?

kcmash

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Having just done a 351C stock stroke build and had the flat tappet cam fail - here's my suggestions.....

Buy a roller cam, or look for old stock lifters from a reputable company - TRW, Perfect Circle, Speed Pro etc. The new lifters I received from a *very* reputable cam grinder were garbage. Talk to a custom cam grinder that understands Clevelands, such as Lykins Motorsports or Bullet. Tell them your goals and setup, they'll hook you up right. I ran the classic Motorsport 214/224 - .510"/.536" hydraulic cam in a car with a 4 speed and 3.00 gear without issues. 4V Clevelands like a dual pattern cam with more exhaust duration. If I were going to use an off the shelf grind, it would be one of the Lunati Voodoo units. 

Use a flat top piston with the proper compression height - Keith Black hypers, Wiseco or RaceTec. This will save money on zero decking the engine. TRW forged have a lower compression height, are heavy and require extra machine work. With the closed chamber heads and proper quench height setup, premium fuel is not a problem. 

The stock multigroove valves, springs, keepers and retainers are junk, throw them in the trash. Replace with quality Ferrea or Manley single groove valves, with the balance of parts to match the cam. Don't bother with the studs and guidplates machine work. The Crane stud conversion or Scorpion adjustable will be just fine. 

Replace the rod *nuts* with ARP hardware. The stock rod bolts are plenty strong. 

 

A couple links to some good build info

https://www.corral.net/threads/budget-351c-rebuild-and-dyno-test.2092114/

https://pantera.infopop.cc/topic/engine-build-and-dyno-results

 

Pics below are from one of the FB 351C groups, impressive numbers for a fairly stock build. 

 

351cjspecs.JPG.e105f6032132385ee7437b18d70b8f47.JPG

121615773_10157923343625432_1238766786299845915_o.jpg

 

 

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 KC, I guess I missed what actually failed on the old engine. It doesn't matter now, but I'm just curious. Picking the right machine shop is the most important part of any build. Did they tell you how much bore wear/taper there was? Do they have a proper deck plate? Can they accurately measure/adjust deck height (critical in determining piston pin location)? Assuming they can do all of that and more, you can move on to parts selection.        

Unless the budget is very tight, I'd opt for forged pistons and float the pins. Be very careful about selecting a piston with an appropriate pin location (compression distance). Get this wrong and the piston will be too far down the bore at DTC, not enough compression. Or, pistons too far above the deck at TDC to be used/too much compression. I can recommend Mahle pistons and rings for an off the shelf piston. I can also recommend Auto Tech/Race Tech pistons if you need to tailor pin locations or want specific valve relief CCs, dish volumes, ring thickness, gas porting, etc. There are real advantages in using the newer ring technologies (thinner rings and better metallurgy) now available and proven. Randy Gillis at Auto Tech is easy to work with and very knowledgeable about 351C and all Ford engines. They will make most changes at no extra charge. Once you have enough information, use the Diamond Pistons compression calculator to figure out static and dynamic compressions. Dynamic compression is not a "Be all end all" number, but it is an indicator of resistance to detonation. I agree with Boilermaster, 7.9-8.1 dynamic is a good number for pump premium gas.

Have the rods magna-fluxed and checked for Center to Center distance and roundness. At a minimum replace the rod bolt nuts with quality aftermarket nuts (known failure item). Make sure the flywheel and damper are good and the outer ring has not moved BEFORE everything is balanced. Have them measure and set bearing clearances. When the clearances are known then decide on wether or not a high volume oil pump is advisable. An adjustable timing set makes degreeing the cam a LOT easier. If you are not set up to degree the cam, have them do that. Given what you have said about the cam, both Comp and Lunati make an improved version of the B351 cam with hydraulic lifters. If you want something closer to optimum, Contact Brent at Lykins Motorsports in Kentucky. When the cam  and lifter are in, rotate the engine and watch the lifters. If they don't rotate, there is a problem with cam taper or lifter radius. Getting valve train geometry right is important, it is easier with adjustable rocker arms. No matter what pushrod lengths are called for, a minimum wall thickness of .080 should be specified (you wouldn't believe how much thin wall pushrods flex). Do all you can to make sure the engine starts quickly, use break in oil, and follow break-in procedures, don't just let it idle at 2000 RPM for 20 minute, vary the rpm periodically.

Assuming the stock valves have been replaced have them check the guide clearances and do a 3 or 5 angle valve job if needed. Use appropriate spring pressures and installed spring heights for the cam selected. The D0AE-L intake is not a terrible intake, a 1/2 or 1 inch spacer does help out above 5000RPM. The block should be magna-fluxed, lifter bores checked, and the cylinder bores should be sonic-tested before any machine work begins to make sure the block is usable. If the budget permits, an extra capacity oil pan is always a good idea.

As for assembly, it depends on the tools, experience, and confidence you have. The plus side to the machine shop assembling the engine/ short block is if something is not right they can't blame it on you.

It can be done with less effort, time, and expense using stock or less expensive parts. It all depends on what you want and what the budget will support. DO NOT buy a engine rebuild "kit" none of them contain high quality components for use in anything other than a grocery getter engine, if that.

I hope all goes well with the new build and you are back on the road soon. 

Chuck

 

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6 hours ago, Hemikiller said:

Having just done a 351C stock stroke build and had the flat tappet cam fail - here's my suggestions.....

Buy a roller cam, or look for old stock lifters from a reputable company - TRW, Perfect Circle, Speed Pro etc. The new lifters I received from a *very* reputable cam grinder were garbage. Talk to a custom cam grinder that understands Clevelands, such as Lykins Motorsports or Bullet. Tell them your goals and setup, they'll hook you up right. I ran the classic Motorsport 214/224 - .510"/.536" hydraulic cam in a car with a 4 speed and 3.00 gear without issues. 4V Clevelands like a dual pattern cam with more exhaust duration. If I were going to use an off the shelf grind, it would be one of the Lunati Voodoo units. 

Use a flat top piston with the proper compression height - Keith Black hypers, Wiseco or RaceTec. This will save money on zero decking the engine. TRW forged have a lower compression height, are heavy and require extra machine work. With the closed chamber heads and proper quench height setup, premium fuel is not a problem. 

The stock multigroove valves, springs, keepers and retainers are junk, throw them in the trash. Replace with quality Ferrea or Manley single groove valves, with the balance of parts to match the cam. Don't bother with the studs and guidplates machine work. The Crane stud conversion or Scorpion adjustable will be just fine. 

Replace the rod *nuts* with ARP hardware. The stock rod bolts are plenty strong. 

 

A couple links to some good build info

https://www.corral.net/threads/budget-351c-rebuild-and-dyno-test.2092114/

https://pantera.infopop.cc/topic/engine-build-and-dyno-results

 

Pics below are from one of the FB 351C groups, impressive numbers for a fairly stock build. 

 

351cjspecs.JPG.e105f6032132385ee7437b18d70b8f47.JPG

121615773_10157923343625432_1238766786299845915_o.jpg

Thanks Hemikiller!  Just the type of help I am looking for.

kcmash

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Chuck,

I have not torn the old engine down yet, it’s still in the car for now.  I did run a bore scope into #6 to see the cylinder wall had failed.  Unsure if that is the cause or the result.

I talked with some local guys here who own Classic Fords and they gave me the name of this shop I went to.  I guess the do a lot of corvette restoration and engine work locally.  Anyway,  they said they were going to clean it and give it a check over for main journal wear, taper, cracks, warping, etc. and call me before doing any work.  They were the ones that told me I needed to go to .030 over because that is what’s available today.  They said the .010 are not available any more.  My web research agrees.  I am listening to this team and wondering if I should possibly move to another shop.  I picked this one because I have testimony from the Ford guys that used them and they are happy with the results.  It’s hard to discount that recommendation.

For oil pump I want to stick with standard volume based on my problem earlier this year.  For intake, you stated the stock 4v intake is terrible, I assume that statement is based on poor intake velocity based on the runners.  I do have an Edelbrock Performer II intake laying around, but don’t know if that  is any better.  I want to look as stock as possible(I don’t mind the aluminum intake look) and definitely want to be able to keep the original Ram air system on the car.  So what are you suggesting for a better intake.?

As for engine assembly, I have the skill there.  I just don’t have the hot rod brain to know all the little upgrades that will let the beast breathe and effortlessly stretch its legs.  Before the engine failed I was thinking I needed to go up in carb size as the power felt a little inconsistent at highway speed.  I currently have a Holley 670 ultra.  I hear I should be doing a 750.

For a cam in the failed engine I was using the SVO M6250-A341 , .510/.536  duration 292/302.  I am afraid to harvest that from a failed engine, but it seemed like a fun running cam considering I never really got to drive the car much.

kcmash

 

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KC, I said the D0AE-L is NOT terrible. Use it if you want to do so. +.010 pistons are available from Auto Tech/Race Tech, just call them (others as well). The shop telling you that +.010 pistons are not available (just lazy people) coupled with them being Corvette specialist, is a bit of a red flag for me. There are much better cams than the A341 out there now. They all require stronger than stock springs. If the 670 worked well for you, use it again. You can change it out later if need be. Chuck

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Chuck,  

Sorry I misread your intake comment.  That is good news as I have not seen a good aftermarket intake that matches the intake ports on the 4v heads.

I am seeing a lot more decisions surface than I anticipated.  I was hoping the rotating assembly be be a no brainer.  Now I am seeing all kinds of options for stroking, boring, and piston choices I was not planning to filter through.  Hopefully I can get that one answered soon and than focus on a cam selection.  
 

My fear with going roller at this point is all the cost and options.  Looks like there are cheap ones out there, and quality ones.  I was hoping to, and maybe I can, go to one of the recommended cam sources and say I want a complete roller cam set for this engine.  CAM, lifters, link bars, push rods, springs, and timing gears.  Then I focus on upgrading the valves and getting back on the road.

Not sure if the machine shop is lazy.  I think they said that no one typically has .010 on the shelf.  .030 is what is in stock out there.  Either way, I need to get the wear and taper readings before I make that choice.

I wish I could get some answers on the weekends.  My meeting schedule barely gives me time to call during the a week.

kcmash

kcmash

 

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Just going to throw this out there, lead times on everything right now are horrible. Everything is out of stock, and prices have increased. Be prepared to wait for months for that one item you need. 

+1 to what Chuck said regarding AutoTec. They'll make you anything you want and their lead time usually isn't terrible, but a phone call will answer that question. If you only need .010" to clean up, then order .010" pistons from them, price is around $550-ish. Considering that TRW 2379F are now about $450 at Summit, it's a no-brainer. 

Blue Thunder and Scott Cook intakes are top notch if you want an aftermarket dual plane. They run about $600. 

 

 

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"That is good news as I have not seen a good aftermarket intake that matches the intake ports on the 4v heads." Don't worry about exact port matching, it isn't the big deal that people have made it for the last 75 years. My Boss 347 has an intake with runners that are significantly smaller than the ports in the heads and it makes 526 HP/ 434 TQ, 10:1, Flat tappet cam. Nail down what the bore is going to be and then talk to Brent Lykins about cam and valve train components. He knows what he is doing and can sell you parts as cheap as Summit or cheaper. If you do use a flat tappet cam use lifters made by Morel no matter what name is on the box. And check for lifter rotation prior to starting the engine. I hope all goes well. Chuck

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I have been in contact with Brent Lykins.  He hit my goals for a cam and I will order through him.

For those of you that have done the 351C roller conversion, did you use the conversion with the valley octopus, or lifters with link bars?

Also, what is the prediction for cleanup on the cylinders of the 115k mile Cleveland?  .010, .020, other?

kcmash

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Kcmash,

You probably wont have to worry, because if Brent Lykins is going to spec. and build a cam for you, he will probably NOT let you use the (spider & dogbones)  there are 2 threaded holes that need to be added to the valley in the block and some Clevelands also need machining around the lifter bores

for the dogbones to sit level when both lifters are at the bottom of their bores.

As I recall, max. lift with the spider and dogbones is just a little over .500'' valve lift.

Plan on going link bars and measuring for custom length pushrods.

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I used a Lunati Voodoo roller cam with Lunati link bar lifters and they are working great. Just remember to get a steel distributor gear and steel cam plate. Do not use original iron gear!

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