Cast iron vs alum block?

[eric1h]

So, looks like I'll need to source a new block after very heating mine badly at the last race.

I am having a hard time sourcing a good clean used alum block, but found a few good deals on a cast iron block. Essentially the same engine, reusing all my original internals. The cast if block is about 80# heavier, but should be more stable and reliable. Thoughts on whether the weight is wrth the added reliablity ?

[FishFind]

Could not answer that but I have a Iron block in my every day driver and it will go to hell and back.

[boothkc]

What base engine are you running?

[eric1h]

I am "currently" running an LS-6, I would essentially switch to a cast iron LM-7 which is the exact same block design, all my original rotating assembly, cam, heads, etc would move over. and I would bore the LM-7 out from a 5.3 to a slightly larger 5.7...

I am just struggling with adding the extra 80# back to the car, one major reason I moved to the LS-6 from the 4.6 was to shave weight and add power, now I would be adding a lot of it back to the car... But the added reliability may be worth it. I cant replace the block every time something minor happens...

[NZGTRA17]

Originally Posted by eric1h

I am "currently" running an LS-6, I would essentially switch to a cast iron LM-7 which is the exact same block design, all my original rotating assembly, cam, heads, etc would move over. and I would bore the LM-7 out from a 5.3 to a slightly larger 5.7...

I am just struggling with adding the extra 80# back to the car, one major reason I moved to the LS-6 from the 4.6 was to shave weight and add power, now I would be adding a lot of it back to the car... But the added reliability may be worth it. I cant replace the block every time something minor happens...

What damage is causing the block replacement Eric?

LS engines are dime a dozen over here second hand now. I would have thought you guys would be swimming in them! When I have needed a replacement block I have normally picked up a complete used engine and parted the rest of the bits out.

You may notice the 80lbs balance wise when you are driving but after a few laps it will feel like normal. I was dead keen on a Dart alloy block but couldnt justify the $$ in the end. Your overheating experience has sealed it for me now Eric..........alloy blocks are out of my price league!!

On another note quite a few LS525's are turning up over here now in race cars. Seems to be a good option $$ for hp. We ran against one in the last round of the NZ Endurance champs. Was very even with us in a straight line in a car with better aero's than the Panoz and similar weight. He thought he had around 560 - 570hp due carb and exhaust mods on top of the LS525 package. Food for thought. May have considered one myself if they were around when I started on the 369.

Kel.

[eric1h]

Kel, apparently the #8 cylinder is "twisted" out of round and unable to bore hone back to round without exceeding the max bore size for the LS6 block.

a NEW replacement block for the aluminum is @ $1000

I think I found a good used replacement for $450 and what I'll likely do is replace the block for now, and then start building a 6.0 cast iron motor and (hopefully) work to replace the motor during next years off season. and sell off the LS6. A 6.0 LQ4/9 with L92 heads can put out 450-500hp pretty easily with good drive-ability and lots of low end torque and come in under $3k. For the extra 80# I'll make up the HP and have something that SHOULD be more robust.

[NZGTRA17]

Originally Posted by eric1h

Kel, apparently the #8 cylinder is "twisted" out of round and unable to bore hone back to round without exceeding the max bore size for the LS6 block.

a NEW replacement block for the aluminum is @ $1000

I think I found a good used replacement for $450 and what I'll likely do is replace the block for now, and then start building a 6.0 cast iron motor and (hopefully) work to replace the motor during next years off season. and sell off the LS6. A 6.0 LQ4/9 with L92 heads can put out 450-500hp pretty easily with good drive-ability and lots of low end torque and come in under $3k. For the extra 80# I'll make up the HP and have something that SHOULD be more robust.

Ah, not good. Assume they cant sleeve the affected cylinder Eric?

Finished fitting the flatbottom to my car yesterday. Have shed a tear over every lb added to the weight (used 4mm alumalite sheet). Mounting up the diffusers in the next day or so with any luck.

Kel.

[eric1h]

resleeving an LS block seems to be frowned upon, for one reason or another, Dry sleeves ten to shift and leak coolan, wet sleeves are VERY expensive. Cheaper just to buy a new block.

I think I have a line on a good LS6 block and will build a 6.0 iron LQ9 motor throughout the season.

It's an extra 65# but should get me in the 450-500rwhp range with a set of good L92 heads! a pick up of about 70-80hp from where I am now, and I can probably sell my LS6(if its still in one piece) for as much or more than i paid for the LQ motor.

[panozracing]

@ Kel - pictures pictures pictures of that sexy flat bottom and diffuser......how much weight did you add? I cooked my motor at Winterfest in the 90 min. enduro...heat soaked on my pit stop with the car off and the fan on....she didnt recover.....My plywood splitter did awesome and the car turned some amazing times on old tires right till the bitter end.

My engine builder wants to replace the heads. After 5 years and lots of heat the rockwell hardness of the mating surface is compromised and new heads are the way to go. He also told me the skirts on the pistons are showing wear so its a complete replacement/rebuild ... UGH....

While I am at it I have Griffin making me a double row top of the line radiator and spal fan with shroud....thats almost $1k. That thing better keep my baby cool this time.

Just keep throwing money at it till it goes fast and doesnt break....well at least I am laughing about.

Rough January....my toter home and the 42' stacking trailer needed a new roof....OUCH....The hauler is costing more than the race car and its all coming at once....

Someone tell me this is fun....pinch me please!

[NZGTRA17]

Originally Posted by eric1h

resleeving an LS block seems to be frowned upon, for one reason or another, Dry sleeves ten to shift and leak coolan, wet sleeves are VERY expensive. Cheaper just to buy a new block.

I think I have a line on a good LS6 block and will build a 6.0 iron LQ9 motor throughout the season.

It's an extra 65# but should get me in the 450-500rwhp range with a set of good L92 heads! a pick up of about 70-80hp from where I am now, and I can probably sell my LS6(if its still in one piece) for as much or more than i paid for the LQ motor.

Ah well worth the thought Eric. I see there are some very pretty looking wet sleeve sets for sale but figured they may be worth an arm and a leg.

You cant go to far wrong if you get reliability and 450+rwhp. Just loads of fun!!

Kel.

[NZGTRA17]

Originally Posted by panozracing

@ Kel - pictures pictures pictures of that sexy flat bottom and diffuser......how much weight did you add? I cooked my motor at Winterfest in the 90 min. enduro...heat soaked on my pit stop with the car off and the fan on....she didnt recover.....My plywood splitter did awesome and the car turned some amazing times on old tires right till the bitter end.

My engine builder wants to replace the heads. After 5 years and lots of heat the rockwell hardness of the mating surface is compromised and new heads are the way to go. He also told me the skirts on the pistons are showing wear so its a complete replacement/rebuild ... UGH....

While I am at it I have Griffin making me a double row top of the line radiator and spal fan with shroud....thats almost $1k. That thing better keep my baby cool this time.

Just keep throwing money at it till it goes fast and doesnt break....well at least I am laughing about.

Rough January....my toter home and the 42' stacking trailer needed a new roof....OUCH....The hauler is costing more than the race car and its all coming at once....

Someone tell me this is fun....pinch me please!

Shame about the engine Brian. We try not to shut off at pitstops but some regs make us even if we run the dry break fuel system. Hard on engines when they get heat soaked like that. Are you going to use AFR225's again?

I guess the pistons are suffering from the effects of the long stroke. Mine looked scuffed in the 369 after 4 - 5 hours so figure they will likewise have a shorter than normal life. The price you pay for lots of torque huh.

Only got a few rivets to put in to finish the diffuser fit then I will take some pics and post them. Only 20 - 30 hours work so far....... Not so easy when you dont have a hoist and have to work with the car only 18" off the ground!!

Will weight a couple of the bits and estimate added weight.

Kel.

[panozracing]

Originally Posted by NZGTRA17

Shame about the engine Brian. We try not to shut off at pitstops but some regs make us even if we run the dry break fuel system. Hard on engines when they get heat soaked like that. Are you going to use AFR225's again?

I guess the pistons are suffering from the effects of the long stroke. Mine looked scuffed in the 369 after 4 - 5 hours so figure they will likewise have a shorter than normal life. The price you pay for lots of torque huh.

Only got a few rivets to put in to finish the diffuser fit then I will take some pics and post them. Only 20 - 30 hours work so far....... Not so easy when you dont have a hoist and have to work with the car only 18" off the ground!!

Will weight a couple of the bits and estimate added weight.

Kel.

Yes, we are going with the AFR225's again. I dont think they did anything wrong and performed well. I bought a whole new cooling system so hopefully that will solve the problem going forward.

The pistons have about 250-200 race hrs. on them so that doesn't seem so terrible.

[NZGTRA17]

Originally Posted by panozracing

Yes, we are going with the AFR225's again. I dont think they did anything wrong and performed well. I bought a whole new cooling system so hopefully that will solve the problem going forward.

The pistons have about 250-200 race hrs. on them so that doesn't seem so terrible.

Yup, can't complain about that number of hours out of the engine. Have you been using the standard Panoz fitted plastic tanked radiators and the standard size Panoz fitted oil cooler up till now Brian?

Kel.

[panozracing]

I meant 150-200 hrs. but still I think that is fine.

I have been using the stock Ford radiator and plastic coolant Ford overflow. But not anymore. Going Griffin double 1.25 core with 3" tanks on the sides. Inside one of the tanks is a power steering fluid cooler.

I still use the setrab oil cooler in front of the radiator but my motor also has a 4 gallon peterson drysump tank.

[eric1h]

Originally Posted by panozracing

@ Kel - pictures pictures pictures of that sexy flat bottom and diffuser......how much weight did you add? I cooked my motor at Winterfest in the 90 min. enduro...heat soaked on my pit stop with the car off and the fan on....she didnt recover.....My plywood splitter did awesome and the car turned some amazing times on old tires right till the bitter end.

My engine builder wants to replace the heads. After 5 years and lots of heat the rockwell hardness of the mating surface is compromised and new heads are the way to go. He also told me the skirts on the pistons are showing wear so its a complete replacement/rebuild ... UGH....

While I am at it I have Griffin making me a double row top of the line radiator and spal fan with shroud....thats almost $1k. That thing better keep my baby cool this time.

Just keep throwing money at it till it goes fast and doesnt break....well at least I am laughing about.

Rough January....my toter home and the 42' stacking trailer needed a new roof....OUCH....The hauler is costing more than the race car and its all coming at once....

Someone tell me this is fun....pinch me please!

Sounds like a heck of a time for you too! Sorry to hear! although you appear to be having a rougher time than me! ;-) Brian you can still go LQ9 for probably half the cost or more! ;-)