Just went with a small 4.390 bore this time. Was 4.40 on last iteration.
Some have gone to 4.50 on stock blocks with mixed success. Seems odd
that with the deep dish its still over 10:1 cr... Diamond made the pistons to
be a mirror image of the combustion chamber of the Potter heads with dual
quench pads.
Dwayne
Last edited by 53 Studillac; February 22, 2013, 08:55 PM.
You have an amazing project there. I wish you good luck with the motor, youv'e had some tuff breaks with it.
You probably know this but I haven't seen it mentioned so I thought I'd thow it out there: Caddy 500's have an internal coolant bypass that has caused many an overheating problem. It is best if you plug it. If not, make sure that you have a thermostat that looks like this
not like this:
if you get the thermostat wrong, or run without it, some of the coolant will just go in a circle in the engine and never go to the radiator.
JW (engine builder) sent me these power numbers from a late weekend dyno session.
Engine made best power with a 1250 dominator on a hogged out MTS single plane intake.
Potter intake was not used this time...
32 degrees of timing
RPM HP/TRQ
2600 273/546
3000 353/616
3500 421/629
4000 490/643
5000 647/683
5100 666/685 P*torque
5500 688/657
6000 700/614
6100 704/604 P*horsepower
Impressive? Cant wait to talk tomorrow and learn how the day went.
For those that dont remember the previous engine built by Potter Automotive.
4.40 x 4.40 (535), solid roller with .719/.709 256/264, 11.5:1 compression, 6.86 rods
This version made peak numbers of 652 hp at 5350 and 667 peak torque at 4816.
MTS/JW engine...
4.39 x 4.30 (520), solid roller with .711/.688 249/254, 10.5:1 compression, 7.1 rods
This version has peak numbers at 704 hp at 6100 and 685 torque at 5100. 91 pump gas!
Appears that in this case less is more!
I dont have everything in front of me, but I had figured on less torque with the shorter stroke!
With these numbers there is a legit chance for 600/600 at the rear wheels on the chassis dyno...
Dwayne
Last edited by 53 Studillac; February 22, 2013, 08:58 PM.
And now for the bad news. I should have known when the first message
I got from JW last night was that "We have to talk, call me." So this morning
I gave him a call. He said it runs like a BEAST which is a good thing and that
he actually saw a spike of 740 hp on one pull but for some reason that I dont
fully understand about the electronic controls on that dyno it didnt like the data
and didnt show it above 6100.... It was still pulling hard. 2" headers, 1250
Dominator, not sure what gas, oil pump works great, etc. But....there's always
a but... Both heads are seeping water above the head gaskets somewhere
around the lower head bolt holes. JW was distraught and pissed to the point
he couldnt sleep last night. So the heads have to come off and investigation
performed to see if they can be repaired. If someone is debating on buying
some heads for a street engine from Cadco I could make you a deal on a
powerful short block!
Trying to stay calm...
Dwayne
Last edited by 53 Studillac; September 14, 2012, 08:03 PM.
Are you using copper head gaskets with silicone around all the water openings in the head and block? I have had that problem before and used Stop Leak, it worked.
This version of the engine is using new MTS big bore conventional gaskets
they had made. The last build used Titan copper gaskets and we wanted
to get away from them for a street motor.
Thanks for pointing that out. I will see what I can do... Where is a good place to store
photos on the net these days?
Engine is still in prison in OH. Coated bearings are in, waiting on machine work again.
I went ahead and ordered a T56 Magnum too!
Dwayne
Last edited by 53 Studillac; February 3, 2013, 05:41 PM.
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