[scott70]

The machine shop got back to me and said they have the info on the rods and pistons from the last time they balanced it so he will not have to remove the pistons from the rods.

[HWYSTR455]

You can put the pins in the freezer, and not have to heat the rod excessively to install the pins. Some use a hot plate to heat the rods small ends.

Removal is a diff story, but still don't think it takes excessive heat. It doesn't have to be glowing hot.



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[mgarblik]

I much prefer re-sizing the rod big ends of rods without removing the pistons. (press pins). It's not impossible, but some piston damage has to be expected and it's not necessary. The down side to removing pressed pins your going to reuse: 1. Crushing the pin box 2. Applying enough press to crack/weaken the sheet metal struts around the pin holes. (cast pistons) 3. cracking the piston 4. closing the hole on one end as the pin is pressed out. 5. Moving out a small amount of aluminum with the pin, galling the piston bore. 6. mis-shaping the line bore through the piston. 7. Losing some of the press in the rod when re-installing the old pin. The upside?: None that I know of.

New pistons are an entirely different story.

[sdbob]

I remember making a small press to remove those pins from the 58-62 rods. Used a 5 ton bottle jack, wooden piston support,rod to go through pin.Pitched pistons. It was a thrill when pin first moved.

[mgarblik]

At room temperature, our Sunnen press fixture shows 1500 PSI-2000 PSI typically to get the pin to begin moving. Then it rapidly drops to around 1000 PSI as the pin pushes out. The actual press we shoot for size wise is .0012"-.0015" press fit. Over .002", very hard to install without overheating the rod small end. Under .0008", it is likely the pin will migrate out of the rod, especially if run hard. We all know what that results in. Ford FE engines are a particular problem from what we have seen at the school. Had a 390 where the pin rode on a cylinder wall for so long, it finally cut a groove completely through the cylinder wall into a water jacket!! Incredible.

[scott70]

Well luckily he said he doesn’t need to remove the pistons and will check the big end after installing new rod bolts. I offered to get some new H beams but he said it’s not needed. I don’t believe he’s torn into it yet though. He’s then going to switch it to an internal balance. I couldn’t see anything wrong with the flat tappet lifters just visually . He’s going to check them cause I said if any of them were funky that I was switching to a hydraulic roller.

[Half-Inch Stud]

Upside to removing & R stock cast pistons is you get to inspect the pins and bores. Moot though.

un pressed 3-sets recently and found 1-set with worn pins and bores ( block was full evidence of no oil changes, just top-offs).

Other set had decent pins bores but only the rods and pins prevailed as decent ( that oil was managed)

[scott70]

Looking through some stuff I actually found the invoice from ace. They are 4130 rods. I assume these are plenty strong?

[Skip Fix]

I have a set I got from Ace-still in the original box!

[scott70]

500 hp,,, 5500 rpm shifts?

[HWYSTR455]

I honestly can't recall the last engine that I had with press in pins. Has to have been in the 80s when using TRWs....


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[scott70]

Originally Posted by HWYSTR455

I honestly can't recall the last engine that I had with press in pins. Has to have been in the 80s when using TRWs....


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Everyone use floating pins? Which rods would you recommend? If I was going to make a change I’d have to do it soon. Thing is would I have to change pistons? They’re autotec… if I remember right the pistons came with spiral clips but obviously I didn’t use them and I don’t know where they are.

[Skip Fix]

Yea the 400 I am freshening has TRWs pressed in Crower press in billets-got late 80s.

[HWYSTR455]

Originally Posted by scott70

Everyone use floating pins? Which rods would you recommend? If I was going to make a change I’d have to do it soon. Thing is would I have to change pistons? They’re autotec… if I remember right the pistons came with spiral clips but obviously I didn’t use them and I don’t know where they are.

Well. Rods & pistons would be like $1500 give or take, not sure it's worth it. Another $750 and you get a balanced stroker kit w bearings & rings.

You could have your rods bushed and pins fitted, and locks are pretty standard, inexpensive, even if you got a set from Autotec. That on top of your existing machine work is still not inexpensive. You're probably better off just going with what you have at this point, to avoid project creep.

You could estimate the costs between the different approaches and see where you're at, then make a decision, but the easiest would be to just use the parts you have.


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[scott70]

Originally Posted by HWYSTR455

Well. Rods & pistons would be like $1500 give or take, not sure it's worth it. Another $750 and you get a balanced stroker kit w bearings & rings.

You could have your rods bushed and pins fitted, and locks are pretty standard, inexpensive, even if you got a set from Autotec. That on top of your existing machine work is still not inexpensive. You're probably better off just going with what you have at this point, to avoid project creep.

You could estimate the costs between the different approaches and see where you're at, then make a decision, but the easiest would be to just use the parts you have.


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Wrong or right I said the hell with it and ordered some molnars,, 4340. , bushed for floating pistons. Shouldnt I be able to use my existing autotec pistons?...I looked for the spiral clips that came with them but obviously never used… long gone.I’ll try to sell my 4130s and recoup some of the money. The molnars were 730.00 and come with arp 2000 bolts installed. If anything it makes me feel better,, lol. Overkill I’m sure.

[HWYSTR455]

Yes, you can use the Autotec pistons, the small end needs to have the pin fitted to match the pin size/clearance spec is all. Locks are usually pretty standard, and can source from Autotec if there's a concern. Some pistons call for 2 locks per side, can look that up by the part number or ask Autotec.

Since they are going to check the balance anyway, it shouldn't matter if the rods are diff weight than the previous set. If the machine shop has good notes, they prob already have the bob weight determined and can match the rod weight of the originals.


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[scott70]

Piston paperwork

[HWYSTR455]

Yup, info is there, uses a standard wire lock so it only needs one for each end, spiral locks sometimes require 2 (or more).

Part number is there (990-072-WL), should be cake to order, the numbers dictate wire diameter and length. You need 16, obviously.

Here's some Wiseco ones at Summit:

https://www.summitracing.com/parts/wis-w5242

Clearance is also on the sheet, .003 , but if you want you can call RaceTec and ask. May want to make sure there's nothing special about the lock, but kind of doubt it. (Still better to be safe).

There's some general instructions in the RaceTec/AutoTec catalog on page 67, may want to provide that to machine shop if you don't have complete instructions:

https://drive.google.com/file/d/1-f3...KTZaEy7E6/view

Can ask your machinist if he needs any additional info, but seems straightforward.


EDIT: Pin diameter and wire diameter.


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[scott70]

Originally Posted by HWYSTR455

Yup, info is there, uses a standard wire lock so it only needs one for each end, spiral locks sometimes require 2 (or more).

Part number is there (990-072-WL), should be cake to order, the numbers dictate wire diameter and length. You need 16, obviously.

Here's some Wiseco ones at Summit:

https://www.summitracing.com/parts/wis-w5242

Clearance is also on the sheet, .003 , but if you want you can call RaceTec and ask. May want to make sure there's nothing special about the lock, but kind of doubt it. (Still better to be safe).

There's some general instructions in the RaceTec/AutoTec catalog on page 67, may want to provide that to machine shop if you don't have complete instructions:

https://drive.google.com/file/d/1-f3...KTZaEy7E6/view

Can ask your machinist if he needs any additional info, but seems straightforward.


EDIT: Pin diameter and wire diameter.


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Good info,, thanks!

[scott70]

.003 clearance? Is that the end gap on the lock ring after it’s installed?