New pistons and rings needed

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Nov 3, 2012
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France
My Car
73 Ford Mustang Mach 1 351 CJ all matching numbers, under restoration.
73 Ford Mustang Sprint from Mexico.
Hello,

The block is to the shop waiting for the new pistons cause the block needs to be oversized.

The bigger size is 101.70 mm or 4.0039". I guess the block needs to be machined 0.020" oversize so pistons should be 0.020" plus?

My question:  which brand of pistons should I buy? (engine will be more or less like stock performance).

And could I still use the rods as they are in good condition?

Thanks,

Manu

 
u list 2 cars with different engines. i'll assume u are talking about the 351cj ?? the last one's i used i believe were pro-seal flat topped.

i might add that u would ck the pricing on 30 over vs 20 over. off hand i'd say the 30's are cheaper for many times u bore 30 over.

boring then engine should still be very close to same cost if not the same.

 
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Your shop should not bore the engine until they have the pistons. Different types of pistons require different clearances. If you bore and then the pistons need less clearance you might crack skirts with too much clearance. Too little and they stick. Never bore the engine until you have the pistons you are going to use. Cast, Forged, Skirt design all change the clearances.

I will not make a suggestion have been out of shop too long to know who is good now.

David

 
The mecanic waits i bring him à piston before start to bore thé blockbuster. This is for the Mach 1 engine 4V.

 
SummitRacing.com

If you type 351C in the search you will get a whole cornucopia of results.

I’m sure someone will chime in that is familiar with the 351C 4v, and have some piston suggestions. That being said you should also get one of the old pistons from the machine shop and measure it to verify everything before you purchase new ones.

 
Well, you can spend a little or a lot depending on what you are wanting for power and performance.

If you are looking for a stockish engine as I was, I went with Keith Black KB148 13cc dish top Hyperutectic pistons. I actually had to do my engine twice, but that's another story! The first time the shop installed KB177 flat top and my comp ratio was about 11:1, a bit too high for our gas. The second time it dropped the ratio to just a tad under 10:1. Both these pistons are .020" higher (compression height) than the stock Ford ones so you'll end up pretty much at zero deck height after the block is trued up. You will need to take that into consideration when choosing head gaskets.

Running a 351C 4V and depending on what heads you have, you'll likely need to do some major distributor surgery to get the sweet spot of 34 -36 deg. total mechanical with an initial setting of 14-16 deg. which is what these motors love. Mine only has about 6 deg. of vacuum advance set into it and runs strong and NO spark rattle. I've posted lots on my saga of finding out how to build and curve a dizzy to get exactly what was needed for my engine. The cam I chose was a Melling MTF 2, which has just slightly more lift than the stock Ford one. It suits my need for speed and my wallet!

+1 for sure on bentworker's suggestion. Get an old piston from that engine to be sure of what you need first. It may have already been rebored. Regardless, the experts will tell you that a MAX of +.040" is as far as you can safely go on a Cleveland.

EDIT NOTE: IF you go with Hyprer pistons, the top ring will need to be gapped more than on other types, or it can break the top edge of the piston. While I don't know the exact gap required, your engine builder should, so check.

Geoff.

 
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Engine is stock with original pistons, just want to install same style, oversized.

Didn't know was so hard to find the right pistons. Actually didn't went so far in a restoration.

Thanks for help guys.

 
If you want forged (4032 alloy) pistons look at Mahle or Auto-Tech. Great pistons and rings. Wait until pistons are received to final hone the bores, with deck plates. If you want a less expensive cast piston, look at speed pro. Watch all compression distance measurements as it changes CR a lot. The stock rods should be checked straightness and pin and big end roundness and dimensions. I would suggest new bolts, or at a minimum new bolt nuts. Good luck with the build. Chuck

 
That's pistons were in my engine. I found two of them hit by the intake valves. I understand now why I found some pushrods bended.





 
Have you machinist check the compression distance (from the center of the piston pin hole to the top of the piston) of the pistons and compare that to the factory compression distance. Reinstall the crank and the damaged piston and rod (with bearings), bring that cylinder to TDC and measure to see if the piston comes out of the bore. Is more than one piston showing contact with the valves? Chuck

 
Manu, can you please remind me/us what year engine you have. That could make a huge difference if I'm not mistaken.

I don't have one of my old 71 351C 4V pistons, but just going from (bad) memory, the 71's were totally flat on top. I do know the compression height was 1.650", but other years may be different. With stock rods, the deck height was .028" or depth of the piston below the block surface. If you have a wrist pin, you can measure from the top of the piston to the wrist pin and add (or subtract, depending on how you set it up) half the diameter. You will need the spec for your year engine so you can tell if indeed your pistons are the original correct ones, because obviously something major is wrong. I'm no engine expert, just thinking what could be wrong, but I'm guessing your engine is not as stock original as you think. With valve kissing pistons, either someone's lying if it's supposed to be an original motor, or something broke.

 
Have you machinist check the compression distance (from the center of the piston pin hole to the top of the piston) of the pistons and compare that to the factory compression distance. Reinstall the crank and the damaged piston and rod (with bearings), bring that cylinder to TDC and measure to see if the piston comes out of the bore. Is more than one piston showing contact with the valves? Chuck
The crankshaft has been machined to 0.020".

So I need to pick the block up back home to do that. I should do that before (newbie I am).

Pistons 5 and 8 had contact with intake valves. Could it be hydraulic lifters which were not doing their job? I found some were not moving at all.

 
Manu, can you please remind me/us what year engine you have. That could make a huge difference if I'm not mistaken.

I don't have one of my old 71 351C 4V pistons, but just going from (bad) memory, the 71's were totally flat on top. I do know the compression height was 1.650", but other years may be different. With stock rods, the deck height was .028" or depth of the piston below the block surface. If you have a wrist pin, you can measure from the top of the piston to the wrist pin and add (or subtract, depending on how you set it up) half the diameter. You will need the spec for your year engine so you can tell if indeed your pistons are the original correct ones, because obviously something major is wrong. I'm no engine expert, just thinking what could be wrong, but I'm guessing your engine is not as stock original as you think. With valve kissing pistons, either someone's lying if it's supposed to be an original motor, or something broke.
The engine is a 73 model DOAE-CA four bolts main.

I found push rods bended, maybe some hydraulic lifters were not good, stuck.

I mesured the rod and found 1.650". Nedd to measure the compression piston.

 
Manu, can you please remind me/us what year engine you have. That could make a huge difference if I'm not mistaken.

I don't have one of my old 71 351C 4V pistons, but just going from (bad) memory, the 71's were totally flat on top. I do know the compression height was 1.650", but other years may be different. With stock rods, the deck height was .028" or depth of the piston below the block surface. If you have a wrist pin, you can measure from the top of the piston to the wrist pin and add (or subtract, depending on how you set it up) half the diameter. You will need the spec for your year engine so you can tell if indeed your pistons are the original correct ones, because obviously something major is wrong. I'm no engine expert, just thinking what could be wrong, but I'm guessing your engine is not as stock original as you think. With valve kissing pistons, either someone's lying if it's supposed to be an original motor, or something broke.
The engine is a 73 model DOAE-CA four bolts main.

I found push rods bended, maybe some hydraulic lifters were not good, stuck.

I mesured the rod and found 1.650". Nedd to measure the compression piston.
  OK, I thought it was a 73 you have, not my year for knowledge. From reading further, it sounds to me that something went wrong in the valve train to cause the issue. I tried to find the specs for the 73 motor, but was unable to find the factory dimensions for connecting rod center to center length or the compression height of the pistons. Perhaps one of the more knowledgeable guys will have that info and can help you better. Good luck sorting it out.

Geoff.

 
Manu, can you please remind me/us what year engine you have. That could make a huge difference if I'm not mistaken.

I don't have one of my old 71 351C 4V pistons, but just going from (bad) memory, the 71's were totally flat on top. I do know the compression height was 1.650", but other years may be different. With stock rods, the deck height was .028" or depth of the piston below the block surface. If you have a wrist pin, you can measure from the top of the piston to the wrist pin and add (or subtract, depending on how you set it up) half the diameter. You will need the spec for your year engine so you can tell if indeed your pistons are the original correct ones, because obviously something major is wrong. I'm no engine expert, just thinking what could be wrong, but I'm guessing your engine is not as stock original as you think. With valve kissing pistons, either someone's lying if it's supposed to be an original motor, or something broke.
The engine is a 73 model DOAE-CA four bolts main.

I found push rods bended, maybe some hydraulic lifters were not good, stuck.

I mesured the rod and found 1.650". Nedd to measure the compression piston.
Is D0AE-CA not for a Mustang 1970 ??

 
Manu, can you please remind me/us what year engine you have. That could make a huge difference if I'm not mistaken.

I don't have one of my old 71 351C 4V pistons, but just going from (bad) memory, the 71's were totally flat on top. I do know the compression height was 1.650", but other years may be different. With stock rods, the deck height was .028" or depth of the piston below the block surface. If you have a wrist pin, you can measure from the top of the piston to the wrist pin and add (or subtract, depending on how you set it up) half the diameter. You will need the spec for your year engine so you can tell if indeed your pistons are the original correct ones, because obviously something major is wrong. I'm no engine expert, just thinking what could be wrong, but I'm guessing your engine is not as stock original as you think. With valve kissing pistons, either someone's lying if it's supposed to be an original motor, or something broke.
The engine is a 73 model DOAE-CA four bolts main.

I found push rods bended, maybe some hydraulic lifters were not good, stuck.

I mesured the rod and found 1.650". Nedd to measure the compression piston.
Is D0AE-CA not for a Mustang 1970 ??
  Looking at the only listings I can find for 1970-74 351C engines, I could only find a D0AE-C not CA. CA was listed as D2AE-CA Cobra Jet. So either the casting ID is not being clearly read or there's a different block out there. I suspect it should be a '2' not a '0' If it is D0AE -C, then it is a 71 block 2 bolt main, but drilled for 4 bolt. My guess is it's not a D0AE at all.

 All 351C engines on Ford Racing's basic engine dimensions show the following; Bore = 4.000" Stroke = 3.500" Bore Spacing = 4.380" Main journal Dia. = 2.749" Rod Journal = 2.311" Con Rod Length (mean) 5.780" Deck Height = 9.206" Piston Comp height - 1.647" (Usually rounded to 1.65")

Chime in if someone has better or different info.

Geoff.

 
Manu,

While it really does not matter as to the year of the block, you still might want to verify the casting date,which is located under the block casting number.

As others have stated or inferred, the D0AE-C casting number seems to be all wrong for a '73 Mustang.

That having been said, ALL 351C blocks are essentially the same once you get away from 2 bolt versus 4 bolt main caps; but it should be good to know exactly what you have

...my $.02.

BT

 
Manu,

While it really does not matter as to the year of the block, you still might want to verify the casting date,which is located under the block casting number.

As others have stated or inferred, the D0AE-C casting number seems to be all wrong for a '73 Mustang.

That having been said, ALL 351C blocks are essentially the same once you get away from 2 bolt versus 4 bolt main caps; but it should be good to know exactly what you have

...my $.02.

BT
Exactly, date codes aside, there are no differences when it comes to pistons fitting the block. He needs to match the pistons to the heads, as there may be detonation issues running flat tops on OC heads. My instinct is to install a set of performance pistons (forged) if he's spending the money anyway. Regardless, he has damage to the pistons, which should be replaced. The rods in those two cylinders should also be checked for straightness.

I wouldn't be surprised if the timing chain was the original nylon coated cam gear, which failed and the engine spun with the valves open.

 
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