Motor rebuld/refresh/inspeciton advice (Long)

[Guest tony78_280z]

Motors History: I bought this 350 used, but the previous owner says that I will be its third owner. The first owner was a kid who totaled his truck back when the motor was new. This owner took the motor and installed it into his tow truck. It was a TBI motor, but with the Performer intake (which is now mine) he ran it with a Quadra jet that was running pretty rich. It had an incredibly low geared manual transmission attached to it. I can assume the tow truck ran in the lower RPMs most of the time, and this might explain the lack of wear.

 

 

 

Condition of the motor: In a word Immaculate. The motor looks like it was hardly driven at all. The lifter valley is spotless with no carbon build up. The lifters popped out with my fingertips. The heads had no play in the valve stems. The cylinder bores are smooth and show the original hone marks still. There is no lip or groove at the top of the piston travel. I have yet to pop off the oil pan and inspect the insides. But this preliminary inspection has led me to believe this motor is in damn good shape, and probably doesn’t need a rebuild, perhaps a simply refresh. But I do have a few concerns.

 

 

 

Is there a test or method of inspection for Piston Rings other than a compression test? The previous owner said that the motor sat completely assembled for a few years. (Even had the Quadra carb still atop it.) When I acquired it (a few months ago) I removed the heads for porting and began to inspect the motor. There are no signs of rust or decay from the motor sitting. The piston bores show the original hone marks still, and there is no groove or lip at the top of the bore. The question is: Can rings go bad simply by having the motor sitting for an extended length of time if the motor is still assembled? Would there be some kind of sign I could look for? Judging by the condition of the rest of the motor that I have inspected thus far, I’d say they are in good shape. And see no reason to waste time, energy and money on this process.

 

 

 

The previous owner said that he installed the wrong Balancer this caused it to rub the front seal, and caused a slow oil leak. What else could this rub have damaged? Could it have worn the crank improperly? And how do I check for this? I was concerned about unbalanced crank, but like I said above the piston bores show no sign of wear nor do they have a lip or groove at the top of the bore. Personally, I think he has the right balancer. The seal just needs replacing. Explain the differences between balancers and what should I look for in a Junk Yard specimen?

 

 

 

My Haynes Chevy Rebuild book says that when I replace a Cam, I should replace the lifters. Is this always true? Is there a way to inspect the lifters for reuse? The lifters show no wear, and popped right out of the block with my finger tips. I plan to install a Cam (I’m thinking Single Profile with Duration of 270, and LCA of 12) and am wondering if the lifters must be replaced as well.

 

 

 

Where do I acquire Oil Seals for the heads? I can’t find them in JEGS or SUMMIT, nor are they mentioned in gasket/seal rebuild kits.

 

 

 

What are the O-rings at the top of the valve stems called? And where do I get them? Same thing, I can’t find them in JEGS or SUMMIT, nor are they mentioned in gasket/seal rebuild kits.

 

 

 

I will update to this thread when I have popped off the oil pan and inspected the condition of the crank bearings, but I bet that they look like the rest of the motor. If they look good, then I’m leaning towards just replacing the balancer, front seal, cam, head oil seals & O-rings, and all the gaskets that I broke loose in the inspection process. Drop it in the Z and go!! Call it a mini refresh and performance enhancement.

[tfreer85]

My Haynes Chevy Rebuild book says that when I replace a Cam' date=' I should replace the lifters. Is this always true? Is there a way to inspect the lifters for reuse? The lifters show no wear, and popped right out of the block with my finger tips. I plan to install a Cam (I’m thinking Single Profile with Duration of 270, and LCA of 12) and am wondering if the lifters [b']must[/b] be replaced as well.

 

 

 

Where do I acquire Oil Seals for the heads? I can’t find them in JEGS or SUMMIT, nor are they mentioned in gasket/seal rebuild kits.

 

 

What are the O-rings at the top of the valve stems called? And where do I get them? Same thing, I can’t find them in JEGS or SUMMIT, nor are they mentioned in gasket/seal rebuild kits.

 

Okay for the Cam, Yes it is absolutely necessary to replace the Lifter. If you have ever pulled out a lifter (Flat tappet style) and looked for at it, it is usually tapered and has a specific cut/finish/grind on it to match the grind on the camshaft. As the cam shaft moves the lifter it also spins the lifter at the same time. Where when you re-use a lifter it opens itself up to not spining causing improper wear characteristics on you camshaft. From my experience of buying 350 parts for my trucks, when you buy a camshaft they include the lifters.

 

The O-rings are called just that IIRC, O-rings. For the head seal and most other parts I would use http://shop.enginekits.com/osb/specials.cfm Call Them they are local to me and have done business with them several times. Very knowledgeable and helpful and can customize a rebuild kit just for you. What I would do is even though everything is immaculate, since you seem to have most of the engine dis-assembled is buy a Master rebuild kit including: cast pistons, your cam, gaskets, rings, seals, Clevite bearings, oil seals, freeze plugs ( http://shop.enginekits.com/osb/itemdetails.cfm?ID=65 ). You'll pay just a little to have your cam bearings installed correctly and your Pistons and rods press-fitted. So that should put you close to $200 including the Master rebuild Kit. Now throw in a Harmonic balancer since this isn't a high performance a stock balancer would do fine. You can buy from a JY, but its one of thos parts that if cracked, or the rubber filling is missing in places can come apart and destroy your entired motor. It can also rob you of HP by insuffeciently dampening the crankshaft causing vibrations through the block. A harmonic balancer should run aroun $50 in stock form. Throw in a water pump that which you might as well, $30 or so dollars. If your crank is in great condition you'll be fine, if not add another $50 for a reground crank at 10 under. That would be a simple rebuild that would ensure that it runs for a lot more miles.

 

Rebuild Kit: $155

Minor Machine Work: ~$50

Harmonic Dampner: ~$50

Water Pump: ~30

Reground Crank (Optional): $50

TOTAL: $335

 

Seems relatively simple and inexpensive. Ensures quality rebuild parts and a longer lasting engine. Again enginekits.com can remove the pistons if you don't want to change them, and get new rings. Also to answer another question of yours about pistons rings going bad by sitting. This is a scenario not necessarily the right answer, but rings are like a spring, they exert pressure against the cylinder wall to create a seal. When you compress a spring either to far or for a long period of time, when you release the pressure a spring often will not return to its full height, or as "springy" so I can see pistons rings having the same affect. Hope this helped, hope I answered some of your questions. This is just from my experience and my understanding from reading "Sunnen's Complete Cylinder Head and Engine Rebuilding Handbook" by the Sunnen Corporation and "Automotive Engines" by Tim Gilles.

 

Tyson

[Alf]

if the cylinders look as good as they do, the rings are probably fine also, just check for broken rings.

 

what does the balancer look like thats on your engine? whats the diameter? is it weighted(one side will have a weight cast into the hub)? the 350 is an internally balanced engine so the correct 350 balancer will not have a weighted balancer, 305s and 400s do have the weighted balancer. if you go seaching for one in a junkyard here are a few things to look out for: do not use a balancer that has cracked rubber, find a balancer without a weighted hub, try and find the 8 inch version.

 

the reason cam manufacturers request you change the lifters when you change cam is because the lifters and cam develope a wear pattern, and if you use lifters on your new cam that have developed a wear pattern with your old cam it will accelerate camshaft wear and maybe even wipe out a lobe on your new cam. when a lifter is new the face has a slight convex shape to it and after a while this face can become flat or even concave. lifters can be "reclaimed" by disasembeling(hydraulic) and remachining the face. if i was you i would just buy lifters with the cam, they're cheap insurance.

 

you can find oil seals ond o-rings at a machine shop

[Guest tony78_280z]

Thanks for the replies.

 

So, a motor sitting for a few years won't be bad? I could just reprime the oil pump and fire it up without worrying about the rings? How does one check for broken rings with the pistons still in the block? Or do I need to disassemble it to check these things?

BTW By the casting numbers from the heads, I know that the motor is an 87 or newer.

Thanks again

[Alf]

yep, just make sure it spins freely

if you have the heads off you can check the top rings, but if not you can hook up a vaccum guage when it is running to check.

[Guest tony78_280z]

And the follow up stupid question --> "How do I check the top rings? Visually?"

[Guest tony78_280z]

the reason cam manufacturers request you change the lifters when you change cam is because the lifters and cam develope a wear pattern, and if you use lifters on your new cam that have developed a wear pattern with your old cam it will accelerate camshaft wear and maybe even wipe out a lobe on your new cam. when a lifter is new the face has a slight convex shape to it and after a while this face can become flat or even concave. lifters can be "reclaimed" by disasembeling(hydraulic) and remachining the face. if i was you i would just buy lifters with the cam, they're cheap insurance.

Ok, supose I changed my mind and I think I might stick with the stock cam for awhile, but I went ahead and popped out the lifters without paying any attnetion as to what hole they came out of. I can't just drop them into any random hole can I? So should I buy new lifters for my stock (slightly used) cam? Or do I need a new cam with new lifters and vice versa?

[A. G. Olphart]

Since the cylinders are perfect (as you describe), and no rust, I'd not even pull the pistons. If you had a broken ring, the bits and pieces should have carved/marked up the cylinder walls. If worn out, there should be a ring ridge. You may be able to get a look along side the tops of the pistons at the top ring gap- don't know. I've never been that lucky; by the time I tear something down, it has carbon around the top land.

 

Why did the guy yank the engine from is tow truck? If you don't know, pulling the bearing caps to have a look is a fine idea. Not to be insulting, but it is important not to mix them up or swap them side to side, and bolts must be properly retorqued.

 

You've deduced that mixing up the lifters was not a good idea. It gives you a great opportunity to try out one of those new 'Voodoo' cam kits.

If you can see no wear at all on the bottoms of the lifters and they still have their slightly convex shape (not truly flat or hollow in the center), David Vizard has written that they may be refurbished by sanding them in a figure 8 pattern on fine sandpaper over flat glass. (I don't recall exactly what, maybe something like 600 wet or dry).

I do like his book on building budget Small Block Chevys.

 

 

.

[Alf]

vizard said sand them in a figure 8 pattern with 100 grit emory paper.

 

do about 6 figure 8's and then turn the lifter a 1/4 turn and continue

[Guest tony78_280z]

SO are you telling me that refreshing the lifters and then installing them in a radom order on the stock (slightly used) cam wont cause excessive wear on either the cam lobes or the lifters?

[buZy]

A cylinder compression check. The leak down method. Used in the aircraft industry during annual inspections for checking for broken rings. A cylinder should hold pressure for a determined amount of time. I dont know the specs you need but that is the basic idea. Either way if all cylinders have the same leak down charactaristics I would say you are good to go.

[Alf]

SO are you telling me that refreshing the lifters and then installing them in a radom order on the stock (slightly used) cam wont cause excessive wear on either the cam lobes or the lifters?

 

nope, its just like you have new lifters again.

 

david vizard built a 350 with a stock chevy 929 cam that was in good used condition and fitted it with lifters "reclaimed" in that manner.

[buZy]

Not to step on any toes here but who is david vizard .... Messing around with old lifters period sounds like a very bad idea. Maybe a Pro builder could pull it off but.....The motors out already. Easy to just freshen up the cam and have that insurance. You can pick your powerband too somewhat.

[DavyZ]

Not to step on any toes here but.... Messing around with old lifters period sounds like a very bad idea. The motors out already. Easy to just freshen up the cam and have that insurance. You can pick your powerband too somewhat.

 

You can utilize the used lifters successfully in the very way described by David Vizard---they don't call him "Vizard the Wizard" for nothing. However, IMO it is almost false economy to reuse the used lifters. I'd rather not button up and engine, install it in a car, and then find out that I only made 6 passes on the sandpaper instead of 8, or I didn't press firmly enough, etc. New lifters come with many cam kits and they are a good idea when rebuilding an engine. Just my $.02

 

Davy

[Guest tony78_280z]

1. Lifters:

I keep going back and forth on the lifter issue. There are many factors involved. Garage/Shop location, weather, finances, & my ego all make me want to get the motor in and running asap! Had I taken a moment to record the location of each lifter I wouldn't be having this conversation. I wouldn't mind dropping the motor now and doing a cam sometime later if it meant the motor would be back on the road sooner. I don't want to be stranded with a camless motor somewhere along the road. But I would love to try out this trick and gain some more bragging rights.

 

"To restore them to useable condition, I rum them, in a figure-eight pattern, on 100-grit emery paper on a flat surface such as a surface plate or a sheet of glass. About every half dozen patterns I rotate the lifter with a quarter turn. Whether we like it or not, this action genertates spherical radius on the lifter face. To check how things are shaping up, use a steel straight edge or a quality machinist steel rule, or best yet a percision square. By holding the lifter up to the light you'll be able to see the form taking shape. The edges should be about .001-.0015-in. lower than the middle. Do not chamfer the edges of the lifterand do not put too find a finish on the face as the coarser finish helps with rotation and break in. I have prepped lifters this way, which have subsequently run as many miles as could be expected of a new set. However, it does presume your workmanship and assessment of the crown heigh is good. If you have any doubt, either have your lifter refaced or buy new." - David Vizard, "How to Build Max Performance Chevy Small Blocks on a Budget" Page 106

I've had this book for several months, and don't recal that section If you read that it all sounds wonderful until you get to the last sentence where he is realy discouraging. It is almost as if he is bragging and saying. "Hey I can do this, but you Shouldn't."

 

 

2. Gasket sets: A new question

 

I have an 87-92 block and heads with an eddy performer intake that changes it from TBI to carb. There are lots of well priced gasket sets on e-bay, but none of them specificaly mention my years. What gaskets would be the same from these earlier years? All I can tell is the valve covers change. And those rubber things are reusable, and I was smart enough to save those when I took off the heads.

If the head gaskets, oil seals, and waterpump, timing chain all fit then this would be the most cost effective way to get new gaskets.

ebay.com <-engine set

ebay.com <-engine set

ebay.com <-head set

[A. G. Olphart]

Tony- You haven't mentioned what you are looking for from this engine: highway mileage cruiser, or track car. You have a truck engine, which would be great on the highway with an overdrive transmission; bad idea if you want to race. If you want a bit more of a performance cam, now is the time; just find what your engine's CR is, and don't go wild with the duration. The guy's here: http://www.chevelles.com/forums/forumdisplay.php?f=13 like UDHarold's new Lunati/Holley Voodoo cams. UDHarold doesn't like anything bigger than the 268 on the street with power brakes, and it is probably too big for your CR.

 

Here is a neat calculator:

http://members.uia.net/pkelley2/DynamicCR.html

 

Have you figured out exactly what engine you have (bore diameter?), and what the compression ratio is supposed to be? If not, this site may help: http://www.mortec.com/

How far down in the cylinders are the piston tops at TDC? The right head gasket for your engine is dependent on all these factors. (I think most SBC's start out with pistons approximately .025 down in the cylinders). If they are still at that level, then a head gasket .015 to .020 will help you maintain what compression your engine had.

 

Most rebuilder sets come with thicker gaskets.

[Guest tony78_280z]

You ask Good questions

 

My goal has always been a street driven fun ride. I'm aiming for 300-350hp (at flywheel) with decent gas milage. With 20mpg, I'd be happy. I plan to run stock stall converter with my 700r4. I currently have a 305 in my Z. And it is not gonna cut it. The cam I am considering is cranecamsZcam Nice torque, good HP increase, and not alot of overlap. But like I said, I wouldn't mind doing the cam later. The increase in power will be enough going from a 305 to a 350... for a little while anyway. I estimate that with the stock cam and the heads ported I should push 280hp, and later when I upgrade to the Zcam I'll be over 300hp and around 370 torque. That'll make my Z a little more fun to drive.

 

On to the technical stuff And here is where my ignorance begins to shine

Bore? I thought all 350s had the same bore. How far down at TDC? I dunno I haven't measured it. I promise that when this X-mas chaos is over, I'll check on this and any other information you require.

 

I did notice that while surfing for parts estimates on this site here that most 5.7L GM and Chevy engines in this era (87-92) used the same parts (Cams Heads Etc) According to that I probably have a cam with 194/203 @0.050 with 112 LCA

[jap tin]

stroke on a 350 is 3.48" when one piston is at the top the lowest piston should be down 3.48 inches.

[Guest tony78_280z]

I have the feeling this thread will be miles long by the time I'm done.

 

Gaskets still looking for information

 

So the only difference in 87-92 when compared to earlier models is the intake gasket (since I went to a carbed manifold) and valve cover gaskets (which are reusable and I still got them) and possibly head gaskets? I still havent gotten that bore and stroke information you are looking for due to this crazy holiday stuff. I shall shortly.

 

Final Lift Pushing the limits

 

When discussing just lift, not duration or overlap, what is the difference between lift generated by a cam and lift generated by lifters. Particularly in regard to valve train life expectancy, and reliablity. But also in regards to horse power. Mr.Vizard discusses lift in regards to high lift cams (over .500) but doesn't discus lift generated by lower lift cams.

 

I gotta replace the lifters anyway (see above) regardless of whether I replace the cam now or later I'll be looking at something with lift around 0.42/0.443 with 1.5 ratio rockers. 0.448/0.472 with 1.6 ratio, and 0.476/0.502 with 1.7 ratio.

 

My stock springs claim to be good for up to 0.550 lift, so they are in no danger, and the stock iron heads I'll be using have regular iron guides so it'll be the weak link. Thing is, the final lift I'll be looking at doesn't exceed the seemingly magic number of 0.500 (only by 0.002 with 1.7 rockers)

 

Enough back story and statistics: Now onto my two questions for today.

1. Will my stock valve train handle 1.6 (0.448/0.472) or 1.7 (0.476/0.502) ratio Stamped rockers? Or is there some piece to the puzzle that I'm overlooking?
   
2. If I go for 1.7s (final lift of 0.476/0.502) who sells 1.7s for a Small Block? Vizard mentions the 1.7s in his book, but no part supplier magazine I have mentions them for anything but the big block or full roller rockers (not roller tip rockers). I'm only looking for stamped or cheaper roller tip rockers.
   

Remember, this is a major budget build.

 

Thanks

[getZ]

do the new valve springs just drop right in? I thought stock vortecs had to have the seats machined.