My numbers block is GOOD!

[Stanglover]

Over the past while, I guess I've been a victim of fear. False Evidence Appearing Real. My engine was using oil more than what I would consider normal, Loads of spark rattle, suspected burned pistons etc. etc. Many have commented on this issue. I was afraid I would loose my numbers matching ( yes it DOES have the VIN on it) block, but today I got some good news for a change. The engine has been stripped and thankfully the bores are all good. It will just need freshening up and new pistons and rings to lower the compression ratio to a more manageable 10:1. Recalculating after measurements showed I was right about it being way too high at 11:1 for 91 octane Shell, best I can get here without ethanol. What we did find that has us a bit baffled is the cam has wear on some lobes and lifters, but not on others. It was a Melling MTF-2. It has always been run with zinc additive and good 10W30 oil. My engine shop is going to have it tested in case it is a bad cam from the factory, wouldn't be the first time! This engine only has 5k miles on it. The next issue to address is the reman. factory distributor, which will be recurved and likely put back to points, for now anyway. Also, we will be looking more closely at the carburetor which is a Holley 670 Street Avenger. It seems to run well on it, but I think a trip to the dyno will be in order for fuel /air ratio checking. Looked good the last time the car was on that dyno, so I'm not expecting any issues there.

I'll post more later as I get closer to actually running the motor in car.

Geoff.

 

[barnett468]

.

xlnt news.

as far as the cam wear, that is most likely from improper break in or bad lifters like chinese ones or comp cams ones.

you can get good lifters from crane or cam oiler lifters from crower . . the cam oiler lifters will reduce the chance of a problem occuring.

exactly what type of oil were you using?

.

 

[Stanglover]

.

xlnt news.

as far as the cam wear, that is most likely from improper break in or bad lifters like chinese ones or comp cams ones.

you can get good lifters from crane or cam oiler lifters from crower . . the cam oiler lifters will reduce the chance of a problem occuring.

exactly what type of oil were you using?

.

Barnett468, thanks,

The lifters I believe are also Melling, as are the springs. A new cam is definitely going in, so choice is critical. The engine was broken in on their stand using Lucas Zinc break-in oil. It was changed at 600 miles as recommended for Castrol 10W30 and that is what I usually use with Zinc additive.

Here's another question for you. The pistons used were KB177 flat top. They have a compression height of 1.670", Factory was (about)1.650". The compression is too high for 91 gas, been over that before. They are suggesting turning .020" off the otherwise good pistons. I'm a machinist and I'm skeptical that the pistons would not lose integrity. What do you think on this? I would likely chose Speed-Pro forged flat top as the are 1.647" comp. height.

 

[will e]

That is great news. You might consider going with a roller cam. You get a much faster ramp and no break in worries. You can go a little more agressive without loss of idle quality. They cost more but it might be worth it.

Get rid of the points. You just can't keep it in tune with points. I am an old school fan but points are no bueno.

 

[Jeff73Mach1]

I would not machine the pistons if they are cast or hypereuteric. If forged it might be okay depending on the thickness of the piston material.

You could run a thicker head gasket like this http://www.jegs.com/i/Cometic-Gaskets/245/C5871-075/10002/-1?parentProductId=2849496

That would give you .050 more height compressed than a stock gasket and would drop your compression. Also cam choice can reduce dynamic compression and allow your engine to run with your current piston combo. You need to talk to a custom cam grinder and I would spend the money on a roller cam set up-it will make break in much easier.

 

[barnett468]

Yeah, machining the pistons is not a great idea, but if you have closed chamber heads, there is no way i would use a thicker head gasket because it reduces the quench/sqush area, however, putting the pistons down in the bore and using a standard thickness gasket will reduce the quench also.

there are many ways to kill a cam during break in . . if your spring pressure is over around 280 open, you may kill the cam during break in.

putting zinc additive in oil is not a good idea and can actually cause problems, plus it sometimes doesn't stay in suspension in the oil and simply falls to the bottom of the pan.

its might be helpful if you post the combustion chamber size and bore size and stroke so we can see just what we are dealing with.

 

[Stanglover]

Good comments all. With the dismal performance of our Canadian dollar, cost is a bit of an issue and the budget is slimmer than it used to be. I have to go with the best bang for the buck............ literally!

I too do not favor machining pistons as even though they would all be weighed and balanced, it might upset the integrity of them. The pistons are KB177 hypers. Comp height on these is 1.670" compared to approx. 1.650" factory on the factory rods. Plan is to remove .020" which would bring them inline with the original. Speed-Pro forged are 1.647" comp height and within a reasonable budget and a possibility.

The heads are D0AE-GA closed chamber with a volume of around 64CC +/-. If I used a thicker gasket, I would also need to use longer push rods, more cost? Bore is currently 4.030" stroke is 3.50"

Interesting comment about Zinc in the oil. Wasn't that the additive that was in ALL oil prior to about the early 80's? What would you suggest for break-in then? A roller set up is unfortunately not in the budget at this time, so I need to choose the best flat tappet cam/lifters I can find for my street application. Good overall power and performance and economy.

Thanks to all for the input. I have to make a decision soon on my best options.

Geoff.

 

[Carolina_Mountain_Mustangs]

Just another opinion. If .020" or .5mm is going to kill the pistons then they were not much good to start with. Before Good pistons were available for the Ford engines we use to cut Chevy pistons all the time. If I were afraid that they were going to heat up I would have them ceramic coated after cutting. It is cheap a great thermal barrier and melts at 30,000 deg.

Just another opinion.

David

 

[Jeff73Mach1]

Here's my 2 cents

11:1 compression can be run on 91 octane gas if the cam selection is proper. Save the money on the pistons and spend it on getting a cam that will allow you to meet your goals. Ceramic coating your existing pistons can be a help in this area as well as polishing the chambers (to a lesser degree)

Excessively thick head gaskets can indeed lead to detonation as a result of the "Squish" or "Quench" area between the piston and the head being too large. That being said, head gaskets are available in a wide range of thicknesses and going from one with an .030 crush thickness to one with an .050, may be okay- to determine the "squish/quench" area you have to know how far down in the block the pistons are at TDC. Unfortunately I can't remember the range that is acceptable, I'll have to look in my engine build notes, but my limited memory is that it is something like between .025 and .060

Here are two good links that are long detailed reads. I think anyone spending the money to rebuild a cleveland engine would benefit from carefully reading both of these threads. I'm not saying everything in them is to be followed blindly, but there is a lot of good information.

http://pantera.infopop.cc/eve/forums/a/tpc/f/5650045562/m/319104265

http://www.network54.com/Forum/654331/thread/1327460021/The+351+Cleveland+Cylinder+Head

 

[Stanglover]

Just another opinion. If .020" or .5mm is going to kill the pistons then they were not much good to start with. Before Good pistons were available for the Ford engines we use to cut Chevy pistons all the time. If I were afraid that they were going to heat up I would have them ceramic coated after cutting. It is cheap a great thermal barrier and melts at 30,000 deg.

Just another opinion.

David

Thanks Dave,

No real decision has been made yet and unfortunately cost is a factor right now. I emailed UEM Pistons to ask their opinion on cutting .020 off the KB177 flat tops. The reply I just got suggests that there is no problem as the top land would still be at .280" and the minimum is .200" so there is lots to play with. Despite my thinking that the KB177's were being damaged by the bad timing issues, this proved NOT to be the case, so I don't have that worry any more. While I do still have distributor issues, that is now another item to address.

It is hard to believe that a very respected engine machine shop, could make such a simple calculation mistake when selecting the pistons given that we had said the compression would not be above 10:1, but I guess S**t happens.

I'll post more on this when I get it all sorted out.

Thanks to everyone,

Geoff.

 

[barnett468]

.

CAMSHAFT

You can not have both good mileage and good performance so pick one or the other . . if you were happy with how it ran with the current cam i would get the same one . . if you like that cam but prefer a different brand, post the part number ad we can look for a similar one in a different brand.

COMPRESSION

ok, you are not understanding the importance of having the proper quench clearance . . it is quite likely that milling .020 off of your head will NOT reduce the potential for detonation very much if at all because it increases the quench/squish clearance . . i try to run around .035" whenever possible.

you have other options.

1. have the combustion chamber enlarged if possible . . this preserves the quench clearance and life is 2.

2. look at the combustion chamber . . notice that it is not round . . you can make a pattern of the chamber with a manilla file folder then place it on the piston and draw the outline of he combustion chamber on top of the piston . . you can then mill the area within the line .030" if the piston mfg says that is ok which it should be . . you have now preserved all of the quench clearance and area.

you could also just put the pattern on the piston and mill everything except for the larger quench pad area since it is the biggest, it is the most important to preserve . . this will cost a little less than milling out the entire pattern,

.

.

 

[Jeff73Mach1]

That's some good advice on mirroring the chambers with your piston cut. Get a price though , cause Hypereuteric pistons are not all that expensive. http://www.summitracing.com/parts/uem-kb148-030/overview/ shows but one example of a piston that might be appropriate for your usage.

 

[barnett468]

That's some good advice on mirroring the chambers with your piston cut.

mirroring is an xlnt choice of words . . wish i thought of that.

 

[Stanglover]

That's some good advice on mirroring the chambers with your piston cut. Get a price though , cause Hypereuteric pistons are not all that expensive. http://www.summitracing.com/parts/uem-kb148-030/overview/ shows but one example of a piston that might be appropriate for your usage.

Jeff, those KB148 pistons are an option and would give me enough performance without other work being needed. The original factory pistons gave .028" deck height plus the gasket that would be around .039" crush thickness. I see Barnett's point about quench and I do to some extent understand what he's saying. I will discuss this with the shop guys and make a decision based on the very valuable help offered here.

Geoff.

 

[barnett468]

.

if your block is the factory 9.206" height, then the kb piston will be .006" below the deck which will give you around 10.6 compression, so somethin aint right somewhere with somethin or someone.

block .......................... 9.206

rod ............................. 5.780

stroke 3.5/2 ................ 1.750

kb piston comp height ... 1.670

piston valve relief ......... 2.0 cc

distance below deck ...... 0.006

bore ............................ 4.030

combustion chamber .... 64.0

gasket thickness ............ 0.040

gasket bore .................. 4.100

compression ............... 10.6

if you use an online compression calculator and put a minus sign before the piston cc it means it has a raised dome . . if you put a minus before the deck height it means the piston is above the deck.

http://www.wallaceracing.com/cr_test2.php

.

 

[Stanglover]

.

CAMSHAFT

You can not have both good mileage and good performance so pick one or the other . . if you were happy with how it ran with the current cam i would get the same one . . if you like that cam but prefer a different brand, post the part number ad we can look for a similar one in a different brand.

COMPRESSION

ok, you are not understanding the importance of having the proper quench clearance . . it is quite likely that milling .020 off of your head will NOT reduce the potential for detonation very much if at all because it increases the quench/squish clearance . . i try to run around .035" whenever possible.

you have other options.

1. have the combustion chamber enlarged if possible . . this preserves the quench clearance and life is 2.

2. look at the combustion chamber . . notice that it is not round . . you can make a pattern of the chamber with a manilla file folder then place it on the piston and draw the outline of he combustion chamber on top of the piston . . you can then mill the area within the line .030" if the piston mfg says that is ok which it should be . . you have now preserved all of the quench clearance and area.

you could also just put the pattern on the piston and mill everything except for the larger quench pad area since it is the biggest, it is the most important to preserve . . this will cost a little less than milling out the entire pattern,

.

.

Thanks again for the ongoing help here. Makes me wish I'd got into engine work years ago before I got old and decrepit!!

As for the cam, Melling MTF-2 with an open 3.25:1 rear end, it gave me enough grunt and with the 670 Holley, got very reasonable mileage. It is NOT a drag car nor will it ever be while I own it, but I don't want a slouch either.

I will discuss your suggestion about milling the pistons with the builder, but I don't know what their capabilities are with that. I possible could take the pistons to my old work place and put them on a CNC, but I would have to talk nicely to my old boss!! OR I could just buy a set of KB148's and be done with it. My rough calculation would yield a compression ratio of about 9.7:1 and the uncut portion at 1.670 comp height, would be at or close to zero deck. Would that work?

Geoff.

.

if your block is 9.206" then the kb piston will be .006" below the deck which will give you around 10.5 compression.

I'm not sure what they milled off to square the block, but it would be between .003 and.005" putting the block height at close to 9.200"

.

if your block is 9.206" then the kb piston will be .006" below the deck which will give you around 10.6 compression.

block .......................... 9.206

rod ............................. 5.780

stroke 3.5/2 ................ 1.750

kb piston comp height ... 1.670

distance below deck ...... 0.006

bore ............................ 4.030

combustion chamber .... 64.0

gasket thickness ............ 0.040

gasket bore .................. 4.100

compression ............... 10.6

Are you talking KB177"s or KB148"s?

 

[barnett468]

.

kb177

with 6 milled off you have 0 deck and 10.8 compression

i will look at the other pistons


kb148

dish ....................... 13.00 cc

compression ............. 9.54

these have some quench/squish band around them and i think in your case, these will work fine, and if you can not return the other pistons, you can probable get $150.00 usd for them on Ebay so you are out $155.00 but it might cost you around that to have yours "mirror" milled.

.

 

[Stanglover]

.

kb177

with 6 milled off you have 0 deck and 10.8 compression

i will look at the other pistons


kb148

dish ....................... 13.00 cc

compression ............. 9.54

these have some quench/squish band around them and i think in your case, these will work fine, and if you can not return the other pistons, you can probable get $150.00 usd for them on Ebay so you are out $155.00 but it might cost you around that to have yours "mirror" milled.

.

Thanks again, that clarification does help in the decision making. The other used KB177's have 5K miles on them and yes, I might be able to sell them as they are in good condition.

Time for supper, talk soon,

Geoff.

 

[barnett468]

ok, used pistons might only be worth $100.00

i will look for a similar cam in another brand.

what is your valve spring pressure?