The same number, MB2403P, is stamped on the upper shell as well as a date code, the size at 0.010, Clevite 77, and the A1.  Date codes are different for the upper and lowers.

I don't have the package any more but the order sheet from Summit reads CLE-MS829P10    http://store.summitracing.com/partdetail.asp?part=CLE%2DMS829P10&autoview=sku

Any ideas on what the "A-1" stands for ? 

Looks like we finish off the trailer wheel bearings and wiring today and let the motor go until next weekend.

Cheers, Mark

Bought the micrometer set from Harbor Freight today, $43.95 + tax.  Double checked them and the included reference blocks against a friends Starrett.  I was amazed, they matched perfectly. 

The crank measures out at 2.740, which is perfect for a 0.010 cut.

Bolted down a main cap and torqued it to #105.  Tried to use the telescoping inside gauge that I also picked up from Harbor Freight.  It's supposed to expand to the inside diameter, then you use the outside calipers to measure it.  It's a POS that has at least 10 mils of slop in it, no way to get a reliable measurement.

Wiped all the assembly lube off the crank and repeated my earlier measurements with the Plasigage.  Still reading 0.0015.

So I've got a crank that's spot on and :

1)  A bad set of Clevite 77 bearing shells,
2)  A bad line bore,
3)  ?

Thanks, Mark

Started putting the motor (468" BBC) together last night for the kid's boat.  The main journal clearances checked out at 0.0015" - 0.0017" which is tight.  Who has used Plasigage recently, is it reliable, or is it now made offshore and is crap?

Rely on the machine shop to have done their job right?  Close my eyes and go forward?

A set of inside/outside micrometers is around $1,000.00 through MSC or McMaster-Carr, that's kinda out for a once every four or five year activity.

Thanks, Mark

Thanks! 

Does the engine then get the regulated water supply and the exhaust manifolds get unrestricted flow?  Can you build up excessive heat in the exhaust manifolds and rubber tubing to the exhaust tips while waiting for the thermostat to open? 

What temperature of thermostat is recommended?  I see 140* mentioned, any guidelines for choosing the temperature?  This is primarily a Havasu boat.

I'll be plumbing the intercooler's heat exchangers as well.  I assume these want a continuous but pressure limited supply of filtered cool water.  If I "T" off the water supply after the pressure relief do I need to add a gate valve or some type of restrictor for the intercooler supply?

Apologies for all the questions.

Regards, Mark

My kit arrived and everything looks good.  We'll pull it apart and polish everything tomorrow.

Cheers, Mark

Don't know yet.  The two younger boys are eyeing for their 19 footer but the compression ratio on their new motor is at 8.5 or 8.75:1.  That's a bit tight for a non-intercooled Roots application. 

If I don't cave in to them then I'll sell it, the EFI spacer/injectors, and the Enderle hat as a package deal fairly cheap.  Pulleys are a 52/50 tooth set for a 3" belt.  Idler brackets mount to the blower.  Manifold is a Crager as I remember.  I'll know within the week what the plan will be.

Cheers, Mark

Thanks, these look perfect but ouch ($$$).  I'll take a look in McMaster's and Grainger's for an "industrial" model rather than one with the "marine" label attached.  I'm assuming that these service only the water demands of the intercooler.

Cheers, Mark

Hello all,

Just picked up an older PFM twin turbo kit for the 20 Spectra. 

My question concerns the water supply to the twin water/air intercoolers.  For those of you with a similar installation - do you bring raw water from the pump directly or do you maintain a dedicated and clean fresh water loop on board using a water/water heat exchanger?  Should I be paranoid about sand and river muck accumulating in the intercoolers?

Cheers, Mark

We've taken a slightly differen approach on the same theme.  We're using the high capacity Holley injectors and feeding internal to the spacer body.  This way there are no exposed injector rails.  The fuel is supplied to the smaller holes in the bridge between the two sides.

Cheers, Mark

Any more feedback?

I'm finishing off the build of the new motor for my kids 19' Spectra and have the gut feeling I've gone too conservative in the cam choice (still in the box at the moment though).  468" BBC, 8.75:1 forged K-B, Dart Iron Eagle heads, Performer RPM manifold, log exhaust manifolds for the moment and an "A" impeller.  Staying with the existing 780 Holley for a carb.

The cam I just bought from Summit was the Comp Cams XM 270 (11-236-4).  It's a flat tappet hydraulic with 270/286 and .544/.547" lift. 

Does anyone out there run this cam and are they happy with it?  Do you feel you could have used a bit/lot more?

Thanks, Mark

Both of our Spectra's run older 780 Holley's with the air horns milled flat and radiused.  Stock these come with dual feeds and dual metering blocks.  Notes from the 20' say 74 pri /78 sec jetting.

Usually can be had complete for $50 or less on ebay or craigs.


Cheers, Mark

Twelve years ago I painted my 20' Spectra with Awl Grip marine LP, using a roller, in my front driveway.  The paint still looks very good today even though it has never been wet sanded, rubbed out, or even waxed.  Cost was around $120 total, used less than a quart of red and a pint of white, plus catalyst, reducer, and accelerator.

I invite you to come over and look at it since you're local.  I have enough white paint laying around the shop for you to do your boat.  You'll just have to buy some epoxy primer and roller sleeves. 

PM me if you're interested.

Cheers, Mark