Need some engine advice....

[wyrmrider]

that just sucks
find another piston builder
you can run the ring oil ring through the pin bore for xxxx's sake

 

[69 GTX]

It'll be interesting to see what the final HP difference will be.

 

[hunt2elk]

that just sucks
find another piston builder
you can run the ring oil ring through the pin bore for xxxx's sake

Apparently that is what @33 IMP is thinking also.....
I am just passing info along that I am being told. Maybe he doesn't want to change the rods which is why he wants to stay with cp, idk. This is getting so frustrating. I just want a motor that makes some power and doesn't detonate.
I did see that 440 Source makes a d-dish for a 500 stroker and asked Brian about that. He told me that theirs is a 26cc and I need 30cc. Like I stated before I know nothing about engines, which is why I hired someone to build one for me in the first place. I also feel as though I need to tread lightly with him because as of now he is doing all of this for nothing and being really good about everything.

 

[4406bbl]

As far as quench distance I would stay at .035-.040 have seen .030 kissing on 4" bore sbc. The rest of the fix sounds good to me. I think the balance will work out too, and he is a smart enough builder to adjust the piston weight a little. You only add half the piston weight anyway so off a little is minor.

 

[Dan64]

Quick point of interest, your build sheet says 76 cc but aren't 240's and 270's 78 cc?.

 

[hunt2elk]

Quick point of interest, your build sheet says 76 cc but aren't 240's and 270's 78 cc?.

There are a bunch of discrepancies with his numbers. I think the sheet he sent me is not for my motor.

 

[hunt2elk]

Time to get this thread updated. Brian called today and said the motor is put together and the dyno'ng is done. So he put in new custom pistons, a different cam, new bearings, and gaskets. Also said he checked the balance. Puts it on the dyno, and guess what? It starts detonating at 3200 rpm sporadically. He says they found that the distributor drive was riding up on the cam. Put some kind of bushing with a set screw on the shaft and everything is fine and been run for 2 hours with no issues. He is adament that this was the problem all along. Curious as to what you engine guys who have been following along think of this? If this is the case, why didn't it show up the first time?
The new compression ratio is 9.6:1. I ended up losing hp, from 595 to 571 and torque went down a bit to 601.

 

[PRHeads]

It lost over 120hp?
Or is that a typo?

If this is the case, why didn't it show up the first time?

Good question.

 

[hunt2elk]

It lost over 120hp?
Or is that a typo?


Good question.

Sorry, typo. Got it fixed.

 

[BSB67]

Here is what I think. I think I cannot come to any conclusion other than Brian is a stand up guy for fixing the problem, irrespective of what the problem was and why.

There are always two sides to a story, and we're only hearing one, and the details and conversations that occurred matter.

The safer you make a motor, the less power it will make, generally.

And for the record I don't know Brian, never even spoke to him.

 

[69 GTX]

I was thinking that gear was pinned, am I wrong? I can see losing 24 hp with a different cam and lower compression. But it should run for ever.

 

[BSB67]

I was thinking that gear was pinned, am I wrong? I can see losing 24 hp with a different cam and lower compression. But it should run for ever.

I think he's refering to the distributer shaft moving up and down and the accompanying twisting that changes the timing. Securing a coller on the shaft under the dist. housing limits the drive gear from crawling up the cam gear.

 

[hunt2elk]

I think he's refering to the distributer shaft moving up and down and the accompanying twisting that changes the timing. Securing a coller on the shaft under the dist. housing limits the drive gear from crawling up the cam gear.

That is what I understood was happening. He thinks it is just a fluke combination of the gear drive and the block. Said it happened once to him 15 years ago, but not since.

 

[BSB67]

They all have some movement if not secured. The specific parts in a motor will probably effect how much.

It's possible that it was contributer to the initial problem. If the combination was on the edge, maybe it would have made a difference, but we never know for sure one way or the other. Timing curve data before and after would shed some light. Not sure why it would not show up and be accounted for in a total timing measurement unless the drive gear movement changes in neutral verses under load.

 

[beanhead]

If, on the street, you are disappointed by 570 instead of 595...you send that engine right back out here to Cali and I'll make sure it never bothers you again!


Ha. I hope that's the last of any problems and you can get out and enjoy it!

 

[dcala84141]

So how did everything work out?
No more detonation problems?

 

[hunt2elk]

So how did everything work out?
No more detonation problems?

Got the motor back last November and put back in the car. Unfortunately the salt trucks had already been spreading by then, so all my toys are in hibernation till spring......

 

[dcala84141]

OK
Let us know in the spring how everything turns out
Good info in your thread

 

[hunt2elk]

OK
Let us know in the spring how everything turns out
Good info in your thread

Will do.

 

[hunt2elk]

OK
Let us know in the spring how everything turns out
Good info in your thread

Time to get this thread up to date and put to rest. Spent the last month fine tuning the carb and just yesterday pulled my A/F meter which was temporarily mounted where the ash tray resides. It is running great with no detonation or pinging. Cranking compression is now 170, compression ratio is 9.6. 13" vacuum at idle, 19" cruising. Timing is 17* initial, 35* total, and 46* all in with the vac. advance hooked up. He has light springs in the distributor allowing the advance to come in real fast. Quicker than I have ever had, but I'm not messing with it because it runs great. Peak torque is 601.3 @ 4500 rpm, hp @ 571 had not leveled out yet when he stopped the pull at 5800 rpm. Very nice with the Strange 60 3.23 rearend in the car. Purrs right along at 70 mph but still has all the torque a guy would want down low for a street car. Starts right up when hot and no dieseling when shut off. He said it was even run with 85 octane gas and timing set at 40 on the dyno to be certain it would not detonate. Runs at 190* with a 22" factory radiator that Bob @ Glen Ray put together for me.
It was an unfortunate and frustrating experience for both Brian and myself, but in the end I am very pleased. We both learned a lot from this. He says that every big block Mopar that he builds from here on out will have that $2 bushing installed before it leaves his shop.
I would not hesitate to recommend Brian and his Dad Fred @ IMM Engines out in CA to anybody looking for a quality motor build.
I also would like to thank all of you very knowledgeable engine guys who responded and gave input as I was working through this issue.