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Engine rebuild questions

I’m about to start my first engine rebuild and I have some questions. First, a little background. I have a ‘94 roller block 351W. I’m going to keep the stock stroke but I am going go with a 0.030” overbore with new pistons compatible with the new Trick Flow heads I will be running. The local machine shop in understaffed so I will end up assembling the short block. I will have them clean the block and inspect it to make sure it is viable before doing any work. I will have them refurbish the stock crank and the rods. When I pull the old pistons out, do I need to mark them to keep them in order? I will have the machine shop bore the block (with torque plates) and install the new pistons onto the refurbished rods. Is it safe to assume I should have the rotating assembly balanced since I will be using new pistons? Should I expect the machine shop to fit the rings to the bores as part of this process? Besides having the machine shop doing a line hone, zeroing the deck to the pistons, and installing the cam bearings, is there anything else I am missing that I should have them do?
 

B67FSTB

The NorCal dude from Belgium
To what I know.
I would mark the piston rods from which cylinder they came off plus mark them front to rear.
Second I would weight each piston/rod/rings assembly and make sure they have even weights.
Balancing damper/crankshaft/flywheel or flexplate wouldn't hurt at all.
My 2 eurocent .
 

Horseplay

I Don't Care. Do you?
Donator
Before taking the block to the shop, break out your die grinder and knock off all the casting flash, parting lines and smooth all those sharp edges. Chamfer the oil drainback holes (this also includes under the oil filter) in the lifter valley while you are at it.

All the parts of the rotating assembly should absolutely be balanced and if at all possible the full assembly balanced as a rotating unit. It sounds like you are having everything machined correctly. No shortcuts. Sizing the rings is not necessarily automatically done by the shops I know unless spelled out in advance as a requested service. It's not a difficult task that you couldn't do yourself but you'd likely spend the same amount or more on the tools as you would just paying them to do it. Them being experienced and you likley not building another half dozen engines I'd recommend just having them do it.

Assembling a short block is not all that difficult if you have the knowledge, tools and patience. The machine shop will have already worked the rotating parts to give the proper clearances. You still need to assemble, measure and verify before final assembly but it's rare when you find you need to go back and perform another machining process. Still, you MUST go through the process. Take your time, follow the steps and it's fairly easy to put one together.
 

Horseplay

I Don't Care. Do you?
Donator
To what I know.
I would mark the piston rods from which cylinder they came off plus mark them front to rear.
Second I would weight each piston/rod/rings assembly and make sure they have even weights.
Balancing damper/crankshaft/flywheel or flexplate wouldn't hurt at all.
My 2 eurocent .
If having the rods refurbished it doesn't matter what hole they end up in as they have been made "neutral". And balancing isn't even an option if building a performance engine. It is mandatory (at least IMHO).
 

Starfury

Well-Known Member
I agree with all of the above.

To add to it, get yourself some plastigauge for assembly to check all of the bearing tolerances.

If you're planning on doing the heads yourself, plan on getting an adjustable length pushrod to make sure you size the pushrods correctly. IIRC, you'll need two sizes due to the twist on the valve locations. I'd offer you mine, but the one I have is for a 289/302, not a 351W.
 
Last edited:

kb3

Well-Known Member
I agree with all of the above.

To add to it, get yourself some plastigauge for assembly to check all of the bearing tolerances.

If you're planning on doing the heads yourself, plan on getting an adjustable length pushrod to make sure you size the pushrods correctly. You'll need two sizes due to the twist on the valve locations. I'd offer you mine, but the one I have is for a 289/302, not a 351W.

I may take you up on that loan…
 

Starfury

Well-Known Member
I may take you up on that loan…
It's just taking up space in my toolbox. However, I think it's the wrong size for standard heads. The TFS twisted wedge heads take different size pushrods. I'll go grab the part # in a bit.

I also have a set of hardened pushrods (Comp Cams 7631-16-SBF) that were set up for my 302 heads, and a set of 7/16" rocker studs. All of this stuff is just taking up space.
 
I’m about to break out the die grinder and I have a question about a hole at the front of the lifter valley that is just left of where the distributor passes through the block. This hole is quite a bit smaller than what it should be based on the feature cast into the block. Any harm in completely opening up this hole?
 

Horseplay

I Don't Care. Do you?
Donator
You don't need to enlarge it but you can smooth the edges. This is a critical drain that lets oil drop onto the timing chain.
 
I’m going to have the stock rods refurbished for reuse. Can I reuse the stock rod bolts or should I have them swapped out for some ARP ones?
 
10-4. I’m looking up rod bolts on Summit, and I am getting confused on what they suggest vs. what the ARP website recommends. Summit says I can use 150-6404 or 154-6006. On the ARP site, 150-6404 isn’t for the 351W. I’m guessing going with the 154-6006 set makes the most sense. Can I reuse the main cap bolts or should I go new there too?
 

Horseplay

I Don't Care. Do you?
Donator
Not knowing the history of the hardware I always replace everything. I've also included a windage tray in all my SBF builds so instead of bolts I use studs. Again, using ARP level stuff is a small investment in good long term insurance.
 

kb3

Well-Known Member
Thanks, engine is still at the machine shop and I need to purchase my heads. Then I will hit you up to borrow the pushrod tool
 
I’m about to start putting my engine back together and I have another question. I decided it would be a good idea to weigh my pistons, rings, and wrist pins and I can get the total weight to within 5.8 grams of each other. Is this good enough or should I try take a little weight off of the heavier pistons to get closer to equal? Is there a preferred area on the piston to remove weight from?
 

B67FSTB

The NorCal dude from Belgium
IMO you can't take any weight of pistons , wrist pin , rings. You can take of some from the connecting rod.
I would weight each part and combine them together to have the smallest differents in weight.
The rest I would grind of the connecting rod to have equal weight.
Just my 2 eurocent.
 

Horseplay

I Don't Care. Do you?
Donator
Weight difference is likely almost all in the rod to begin with. Rods are cast with areas meant to have material removed for balancing. You simply machine off whatever is needed to reach the desired weight. The pistons should all be very close in weight. Depending on the weight variance you can likely use a Dremel with a sanding drum to slightly chamfer the edges of the underside side pin casting or such to remove the necessary weight. You absolutely want to get each complete set-up as close to the same weight as possible.
 
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