215 replies to this topic

[Volvo5.0]

Since my S70 has about 230k miles on the engine I decided to build an engine with fewer miles on it. I had this sitting at the shop literally collecting dust....



It had been picked apart but still had a good engine with about 120k miles on it. I decided to pull the head first before I pulled the engine. I wanted to make sure it looked decent inside before I pulled the engine, plus I remember reading about someone flipping an engine off a stand trying to break the head bolts loose ....



Since this was a LPT engine my original plan was to build the engine using a set of pistons from a V70R to convert it to a HPT. I immediately hit a road block when I called my local dealer and was told the pistons were on back order and probably not available. So after talking to a few people on VS I decided that, since my plans included a set of RSI H-beam rods, I would go ahead and build it as a LPT. The jump from 8.5:1 to 9:1 probably would be ok with stronger rods.

Then the next road block. The machine shop called and said the block deck wasn't flat and the head needed to be milled. So between decking the block .005" and milling the head .011" now my compression would be even higher. Not sure how much, but from what I saw online I'm thinking about .25 to .5 higher. I wasn't comfortable going up to possibly close to 9.5:1 so I was on a mission to find a set of lower compression pistons. I talked to someone else at the dealer and was told the pistons were back ordered NOT discontinued. So since I was going to have to wait on rods anyway I might as well wait on pistons to.

I got the engine back from the machine shop and waited for my rods....



Decided to install the crank while STILL waiting for my rods ....





Finally got the rods on Tuesday ....



Followed by the pistons on Wednesday. Now we're in business!! ....



The rods and pistons will go in this week....more pictures then....

[bigdaddylee82]

So your not going to have your rotating assembly balanced?


- Lee

[TRACStar]

So your not going to have your rotating assembly balanced?


- Lee

+1

That's the main thing I'm having done at the machine shop. Along with head work and possibly vent windows in the block.

I think the RSI rods have to be honed out for the piston pins anyway?

[Volvo5.0]

So your not going to have your rotating assembly balanced?


- Lee

We've used this machine shop for years and they do great work, BUT they don't do performance work. What's the consensus on this? If it should be done then I'll contact a shop that is capable of doing it. As far as the RSI rods are concerned, the new piston pins fit perfectly on mine.

[bigdaddylee82]

What's the consensus on this?

IMHO Balance it!

Machine shop should need your crank, pistons, rods, bearings, rings, flywheel/fexplate, and crank pulley (basically everything that spins). Some may just expect you to get a neutral balanced flywheel, I don't know what the advantages/disadvantages of balancing it with the assembly or by itself are. Talk to someone that knows more than I on that one.


- Lee

[Volvo5.0]

Yeah, it looks like I'll be taking the crank back out. Every motor I've built has basically been just bearings and rings using the existing crank, rods, pistons. I guess when you start changing rods and pistons, then it's important. Thanks

[Black Betty]

FYI, I've used burtonsville Machine shop off old gunpowder for my machining needs. I've never had an assembly balanced but give them a call and they might be able to. I'll be up there sometime this week so i can ask them to.

[volvoskiah]

Yeah, it looks like I'll be taking the crank back out. Every motor I've built has basically been just bearings and rings using the existing crank, rods, pistons. I guess when you start changing rods and pistons, then it's important. Thanks

if you are worried about compression you can get a larger head gasket and that should lower compression a little.

[mdlimy]

+1 throw a mls SR gasket on there, and shaving the head that much is not going to put you are 9.5:1.

[BlackT5]

Crank vents ftw.

So what is the CR going to be with those pistons? 9:1 is not high! I would love a higher comp motor if I could rebuild, more off boost power.

I'm guessing you're upgrading the turbo etc..?

[gilber33]

What exactly do they all do to the rotating assembly when they balance it?

[Volvo5.0]

Crank vents ftw.

So what is the CR going to be with those pistons? 9:1 is not high! I would love a higher comp motor if I could rebuild, more off boost power.

I'm guessing you're upgrading the turbo etc..?

I would be OK with 9:1, but from what I saw online the rule of thumb was machining .020" from the block and head would equate to about .5 raise in CR. I had about .016"-.017" machined off of my block and head, so I'm thinking it would raise my CR about .25 to .4 higher. So I guess since I was able to come up with the 8.5:1 pitons from the R I'll be about 8.8:1 approx.

Talk to me about crank vents??? Haven't heard of it.

[Volvo5.0]

A question about balancing the rotating assembly.....Is it absolutely necessary to have the flywheel to have it done? I'm still driving the car with the current engine and wasn't planning to take it out until I have the new engine ready to go in, so the flywheel is currently being used

Can the rotating assembly be balanced with just crank,rods,pistons,rings,pins,and bearings?

[BlackT5]

I would be OK with 9:1, but from what I saw online the rule of thumb was machining .020" from the block and head would equate to about .5 raise in CR. I had about .016"-.017" machined off of my block and head, so I'm thinking it would raise my CR about .25 to .4 higher. So I guess since I was able to come up with the 8.5:1 pitons from the R I'll be about 8.8:1 approx.

Talk to me about crank vents??? Haven't heard of it.

Crank vents are the little windows at the bottom of each cyl. IIRC all blocks 99+ had them cut in from the factory. It helps relieve/balance crankcase pressure.

[ozzimark]

For the flywheel, no, but you really should. Make sure you mark orientation if you do. The piston weight with rings and pins should all be the same, rods should all be the same overall, and the same on the little end and big end.

How fast do you plan on spinning the engine?

8.5:1 with an 81mm bore and 90mm stroke means the chamber volume should be about 61.8cc. Shaving off a total of 0.034in reduces the chamber volume by about 4.5cc, bringing CR up to 9.1:1. No problem, as long as you make sure the valves aren't hitting the piston.

[Oreo931]

Crank vents are the little windows at the bottom of each cyl. IIRC all blocks 99+ had them cut in from the factory. It helps relieve/balance crankcase pressure.

Can anyone confirm this? I had no idea...

[ozzimark]

Can anyone confirm this? I had no idea...

As far as I can tell, it is true.

[gdizzle]

Where in MD are you? If you're in the DC area, Old Branch Machine does awesome work and I use them for all my engine work. They can do whatever it is you need, and they're pretty cheap.

[lookforjoe]

Looks good so far.

Not sure how much benefit you will really see from a complete balance, the machine shop should be checking weight of each overall assy anyway, to be sure they are within range. Personally, for a DD, I wouldn't (and didn't) bother. I also have the DM flywheel, which would have been a nightmare to factor in, and since I'll be removing it & replacing with KalmarUnion SM replacement, balancing as an assy would have waste of time, imo.