Duke

Every now and then there's an engine that blows up due to a rod failure without running 700 bhp so IMHO it's a much better place to put some money instead of crank work.

billthe3

Honestly, IMO, I think that having a deck plate installed on a relatively low power engine would be a waste of money, but I suppose if you are really concerned about longevity I guess you could do it. I don't like the idea of the pegs between the cylinders and block because it seems like the expansion of the pegs would cause the cylinder bores to potentially deform due to the pressure in only the one area and not the entire circumference.

As for my comment about the o-rings making the cylinders more stable, its because their added thickness means there is a higher clamping force holding the cylinder bores in position as compared to not having the o-rings.

Tom M'Guinn

I assumed he was referring to "decking" the block -- meaning to machine the top perfectly flat. I agree no need to reinforce the block for a 300hp motor!

DDP

Do yourself a HUGE favor and read some books. Real books. Take every bit of advice carefully, there are many different 'opinions' here. As much as there is some sound advice in this thread, there are questionable posts as well. Good luck.

JET951

that's a very uniforming post, you made there DDP. care to elaborate a little? Seems to me Arash isnt after absolute Hp here. a simple freshen up of his 2.5turbo engine with a turbo bolt on kit such as a Vitesse stage 3 will get the results he is after.
We have all seen some bent and broken stock rasrst rods on this forum, although we also have some proof that they can withstand quite a lot of boost. Patricks(333pg333) is running a vitesse stage 5 on his 2.5ltr with E85. the only non stock item in the entire engine is a cometic head gasket. + 1.5 bar boost
on multiple track days. although the engine has some scoring on cyl 4 causing some blowby pressurising the crankcase thats really its only problem.

Dare

I have similar power goals (~350rwhp), however I’m building my car primarily for track use (DE, no real racing). For reference, here are the major things I’m doing to the engine:

- Rebuild head--new valve guides, springs and seals, 3-angle grind, milled flat
- Mill block deck
- Remove oil galley plugs and tap holes for threaded plugs
- Perp drill crank and micro-polished journals
- Coat tops and skirts of pistons (swain tech)
- Lightly hone and lap bores to remove taper and ovality and achieve desired clearance
- Install new ‘slightly-oversized’ rings from Lindsay Racing (to allow for correct ring gap in machined bores)
- Dry-film coat main and rod bearings (swain tech)
- Install late oil pan baffle
- Install oil pickup ring
- Cometic gasket
- ARP head studs
- Check rods for cracks and press-in new pin bushings
- New rod nuts
- New piston circlips
- Notch bell housing
- Lighten stock flywheel
- KEP stage I pressure plate
- Balance crank, pistons, rods, flywheel, pressure plate and gears/pulleys.

I haven’t decided on the turbo yet, but I’ll probably go with Vitesse. I’m also rebuilding my engine harness as well.

Own Goal

Rods; unless I'm way off the 951 rods are forged. That's the nice thing on these engines; forged pistons, rods and a full cradle lower end. Good stuff. I've always been a surface anything you go to enough trouble to take off kind of guy. On a 2.7 911 I did about 20 years ago also line bored everything (split cases). I'll also admit I did get off target on one thing on my build; I got A DEAL on a like new aluminum flywheel. quicker rev. but a little clutch feather on hill starts etc. With that one more piece of advice; watch this site. Some very good hardware gets offered.

gt37vgt

yeh sadly the "full cradle " or girdle set up is not that flash it may be stable when getting cained but the engine Man tells me they are often flogged out and need line boring ..

Notch Bell housing ???

gt37vgt

yeh sadly the "full cradle " or girdle set up is not that flash it may be stable when getting cained but the engine Man tells me they are often flogged out and need line boring ..

Notch Bell housing ???

JET951

funny enough Adam, i have never seen one that has needed to be line bored. and we have seen a few.

DDP

There is no reason to elaborate, that's partially my point. Nearly everything has been said. And more. There are a ton of opinions, the original poster needs to decide for himself. I don't want him to make judgments that will make or break his wallet depending on what a few people on an online forum tell him. There are other opinions to gather, more valuable sources to consider. Go back through this thread and every post is contradicting the previous. How can you possibly make sense of it? Everyone is an expert these days. Instead of pretending to be an expert I simply point out the fact that these are merely opinions and not truth. There is more information to be had. There are many people on this board that have suffered serious money loss due to some inexperienced ignorant advice given. I want to keep that number to a minimum, that's all. Although, as much bad advice there is on this forum, there's good to go with it as well. You see my post as a useless shot at everyone in the thread but it's really just a reminder to keep things in perspective. Let me post my 'opinion' just so it doesn't make me look 'all talk'.

gt37vgt

Well in that case Sean I'm glade i chose to take it home and measure first ..not done yet ..

DDP

Goal is 300 whp...ish. You don't want to waste money where you don't need it?


ARP head studs
No need, factory hardware is more then adequate. Proven and easy. Don't bother.

cometic head gasket
Again, no need. If you want to spend a few extra bucks with the gasket kit, go with the widefire. But honestly, it's just to say you have a widefire (which really hasn't been that impressive ever since the cometic has been out). I've never actually seen a difference between widefire and stock. Anyone that wants to argue that with proof, prove me wrong.

machining the block deck
Not necessary. I would spend an hour cleaning it with a razor blade, very fine grit sand paper (1500 at least). If you want to feel extra cautious, spray on some copper spray before laying the gasket. Machining the deck is only possibly necessary while using a cometic head gasket.

deck plate or pegs
No, no, no. Completely overkill for your situation. Your money is better spent on cheap hookers and alcohol to make them not appear to be cheap hookers.

cross-drilled crank
This is something you could consider. The cause of the #2 rod bearing failure has been discussed since the 80s. I've read a few really detailed reasons on why, but the truth is no one really has a concrete answer. Many things have worked to reduce or eliminate the 2 and or 3 spinning but there were multiple things changed at once. The most convincing argument, in my humble opinion, of course, is the lack of pressure to the 2nd and 3rd due to the position of the hole in the crank. This can be solved by perp or cross drilling the crank. There is also another angle to drill into the crank but machine shops are most easily suited with cross or perp. Either are a pretty simple and cheap thing to have done, while you're there have the crank micro polished to clean it up (this is cheap as well). Whether that will solve the rod failure or not, it's cheap enough to be worth the peace of mind.

knife-edged crank
Hell no, no reason.

balanced reciprocating mass
You could, but this is another one of those "might as well while I'm in there" type of b/s that leaves you with no money in your wallet for more cheap hookers and beer.

crank scraper
There is a benefit to this, but will you really see it? Maybe, maybe not. You can read on these a bit to decide for yourself. The idea is nice, it may help you sleep at night. As far as I recall, these need a bit of TLC before they fit perfectly.

Most importantly I would search through everything on the car and make it mint and up to spec. I think going with a stock clutch is a mistake, I would beef it up. If you don't agree with me, go do a clutch job on these cars a few times and you will. Something simple. I would recommend for street use go heavier on PP but more organic on clutch disc. This will give the clutch pedal a stiffer feel but allow you to slip as you please, no on/off crap where people are doubting your stick driving skills and you never want to drive through the drive through not only because you might stall or rear end the car in front of you but also because your 4 inch exhaust is too loud to hear the kid at McDonald's re-read your messed up order back to you just to find out too late to turn back because you removed your A/C to install a larger turbo with a MAF and you're sweating bullets in the car so you just want to get home.

gt37vgt

LOL yeh most chicks realy don't understand that turbo and AC thing

Dare

https://rennlist.com/forums/924-931-...lutch-job.html