2.7 darton wet sleeved motor with custom JE pistons

[nize]

after 220,000 miles on the original motor, compression in cylinder4 was down about 30%. there was some slight scoring in the cylinder and tests showed the piston rings would need to be replaced. i figured since i'll have to take the motor apart and re-hone anyway, why not go to a bigger bore? thus, i decided to go with darton sleeves bored to 2.7 with custom JE pistons to allow the use of the stock rods, crank, bushings, pins, etc. this would allow replacing just the pistons as well as further boring the sleeves (to a 2.8) should the need arise in the future (hopefully never, but you never know).

one thing i've learned early on is that practically every shop wants to do this work and will tell you they're the best at it. i think the most important question to ask any potential shop is:

have you done this to an identical motor before and if so, can i contact the owners (or can you have the owners contact me)?

basically, i wanted some assurance that the motors they've built were still working okay, as well as the general experience and feedback of the previous customers. i wasn't about to be the guinea pig at my own expense, so this was a critical factor in choosing a shop.

another important factor was that the entire work, from disassembly and cleaning, to machining and re-assembly, had to be performed by the same shop if not the same person. the reason for this was because i have been burned in the past when working with more than one shop where one shop would blame the other if something went wrong later. i wanted one shop/person to accept full responsibility from the get-go.

after hunting high and low, i was fortunate to find a local machinist who had already built four of these identical motors, the oldest of which was still being raced at the track going on 7 years now. this motor was probably the very first darton sleeved block in a 951 and the sleeves are so old that they were before darton drilled the coolant holes around the collar. an image of that motor is here;



and it is being used in this race-dominating car;



i figured if it's good enough to be used in a winning race car for the past seven years, it should be good enough for my car. thus, the trigger was pulled and the build was on.

the donor/spare motor;


what's left of the original cylinders;


cylinders gone;


what's going in;


custom JE pistons going in;


darton sleeves pressed in;


JE pistons installed;


stay tuned, this post will be updated as things progress.

[nize]

custom cometic MLS gasket test fit;


new motor and old;


new motor and old;

[333pg333]

Is it at all possible that the old Zen master who is performing your engine rebuild could contribute to this thread or at least provide some proof to these claims. It's hard not to ask these questions without sounding aggressive and that's not the point. However in context of the lack of similar builds, it would be somewhat surprising to see evidence to the contrary. Seems sort of KUNG FU that this old guy is the only one with a proven background to successful MID builds.
NB I have only found one person on the planet who claims to have a successful motor that has done over 1000 miles with this setup.

As I mentioned elsewhere, I do wish only success in your direction, however I would like to have some form of proof if only for all the failed money I put into mine. Quite possibly we did the wrong thing somewhere along the line. Conversely I'd love to see why.....

[nize]

the old zen master is an analog type of guy. if you were local, i could take you to see three 951 cars with this identical motor that have all racked up over 10k miles and you could talk to their owners about it.

i guess you'll have to wait and see how mine works out.

[2Tight]

Just curious but are you planning on using the same Garrett DBB turbo you have been using on the 2.5L? I know you opted for the #10 hotside so that should help a lot right there with the larger motor.

[nize]

yep.

i've run into a snag. during re-assembly i found out the balance shaft covers do not match the block. when i put them together and torqued the bolts down, i found i could not manually turn the balance shafts. it took a 3-foot breaker bar to turn them. thus, i've asked the owner of the donor motor to see if he could track down the matching covers that go with this block. if they can't find them, i'm at a loss of what to do.

anyone got suggestions?

[2Tight]

Originally Posted by nize

yep.

i've run into a snag. during re-assembly i found out the balance shaft covers do not match the block. when i put them together and torqued the bolts down, i found i could not manually turn the balance shafts. it took a 3-foot breaker bar to turn them. thus, i've asked the owner of the donor motor to see if he could track down the matching covers that go with this block. if they can't find them, i'm at a loss of what to do.

anyone got suggestions?

Man that really sucks. How would the covers ever get separated on a donor block? If worst comes to worst I have a spare 951 block with a scored #3 but at least the BS housings haven't been pulled. I will sell it very cheap. I was just keeping it for an assembly guide for my other rebuild in case I forgot how stuff bolted up.

[bleu951]

Take the crank and pistons out, bag them, and have the balance shaft covers resurfaced, then have the bores for the balance shaft bearings rebored. Install new bearing locating pins, scrub everything clean and reassemble.

It is a bummer, but easier now than later!

[nize]

i figured out how to get them to fit better. re-assembly is progressing again. more info on fitting here;
http://forums.rennlist.com/rennforums/showthread.php?t=396772

[Porsche-O-Phile]

Bummer - sorry to hear. Hope you succeed in finding the original balance shaft covers. If not I imagine you could have a machine shop get involved (but at a price. . .)

If it's not prying too much, do you mind telling me what the Darton sleeving set you back? I've been considering this on a spare engine I have downstairs (I have everything necessary to make a 3.0L turbo engine out of it, except the proper bore sizes). IIRC it's something like $2k out the door for the whole shebang plus whatever it costs to ship the engine to/from Darton. But I'd rather hear it straight from someone who's done it.

Thanks and good luck to you.

[nize]

cost will vary depending on the condition of the motor and other random variables. my cost was just over $3k which included the sleeves and pistons, plus disassembly, cleaning, inspection, machine work, and re-assembly. i got a one-off insider deal on the sleeves, though, which brought my cost down.

the actual time it took him to do my motor was about three days.

[nize]

assembled !

[nize]

[nize]

[MOVOVR951]

Looks great, did you baffle that oil pan yet? I assume you eventually going to start tracking the car. It really easy now....

Good luck, and I can't wait to see it out on the track!!!

[nize]

oil pan is baffled, forgot to take pics of it though.

[MOVOVR951]

Good. Great pics and info by the way. Its nice to have someone document a build like this. Can't wait to see it at speed on the track!

[nize]

motor started up tonight. discovered an oil leak, possibly the turbo oil supply line. i'll have to take the intake off tomorrow and investigate.

sounds nice though!

[nize]

for reference, this is what went in;
http://www.prostreetonline.com/x/darton-mid-sleeves.asp

Darton MID Sleeves

Darton pioneered modular sleeve designs and specialty ductile iron material beginning with their manufacture of top fuel sleeves in 1978. Darton sleeves excel in the harsh environment of all-out racing. Their centrifugally cast nodular composition represents the highest quality of any cast material. The unique matrix of Darton's centrifugally cast nodular iron sleeves provides unexcelled surface toughness. Darton's unique casting process provides a bore finish which, while very tough, promotes quick and total piston ring seal for the most complete combustion possible from each cylinder.

Darton now has engineered a superior solution to open-deck sleeve weakness by using a unique design which creates a solid deck of sleeve flanges held in tension, reinforcing the upper deck area and provides for in-field replacement with what they call “Modular Integrated Deck” (MID).

The Darton MID kits feature:

# Improved block integral strength
# Improved cooling
# "Wet sleeve" replace-ability
# Increased horsepower output potential
# Superior oil and compression control
# Street or strip application
# Kits can be installed by your local machine shop
# Full installation manual with every kit sale
# Superior cylinder sealing and ring wear
# Ductile iron w/130,000 psi tensile strength

[nize]

fixed leak, it was indeed the turbo oil supply line.

car runs and sounds great! will post dynos as soon as it's broken in.