304 cu in conn rods and block clearance

[4tford]

building a 304 using the speedway rotating assy. When using the scat H beam rods will I need to relieve for rod clearance or do they normally clear?
Thanks Bill

[KiWinUS]

Be sure to check rod to cam clearance !!! This can be tight .

[Pete]

Originally Posted by 4tford

building a 304 using the speedway rotating assy. When using the scat H beam rods will I need to relieve for rod clearance or do they normally clear?
Thanks Bill

One engine I built had a 4.430 stroke SCAT crank with Scat rods.
They cleared by about 1/16 in.

[4tford]

thanks guys Pete do you foresee any clearance problems with the 425 cam??

[Pete]

Originally Posted by 4tford

thanks guys Pete do you foresee any clearance problems with the 425 cam??

No. The cam in that engine had .460 lift and was ok.

[4tford]

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Thanks sounds like I am on a roll

[KiWinUS]

Pete please correct me if I am wrong , but it is more the size bass circle the cam has been ground down to than the lift .

[4tford]

KiWinUS I just had a good chuckle when I looked at your avatar. Trying to imagine the accent of Kiwi and North Carolina mix.

[KiWinUS]

Originally Posted by 4tford

KiWinUS I just had a good chuckle when I looked at your avatar. Trying to imagine the accent of Kiwi and North Carolina mix.

4T your not the only one that has commented on my messed up mixed up "accent" ! 30years here in the south has rubbed off ! But I love this place !!!
Thats Edsel Ford in the back of my avatar pic , he could understand me ok , probably from all his years of living in Australia.
Cheers
Tony

[Pete]

Originally Posted by KiWinUS

Pete please correct me if I am wrong , but it is more the size bass circle the cam has been ground down to than the lift .

It is more the duration of the cam that causes problems sometimes. The long duration cams sometimes are close but I have never had to do anything to get more clearance.
Even with .500 lift and a 4 1/8 stroke everything cleared. (Jazzy)

[KiWinUS]

Originally Posted by Pete

It is more the duration of the cam that causes problems sometimes. The long duration cams sometimes are close but I have never had to do anything to get more clearance.
Even with .500 lift and a 4 1/8 stroke everything cleared. (Jazzy)

Thanks Pete !!! Much help as always !!

[KiWinUS]

4tford , keep us well informed & updated on your build please !!!

[4tford]

will do, never having a lot of trust in suppliers I took the balanced rotating assembly my buddy purchased on line to my local guy who does a lot of high end racing motors of various breeds. He did the balance all over again. I said Speedway in my original post but only as a reference to what we have. The crank was out a fair bit. He said the rods were bad but the Ross pistons were perfect. This is the block I am using. I am starting to get a routine that works for me. After the block is back from hot tank and magnaflux I do any porting, drill for the adj. lifters and another real good cleaning inside and out. I have a scope to look at the inside of the block. Wash down with "Goof Off" and then Acetone, mask and paint. When the paint is dry I then do another good cleaning and wash with soap and water and then rinse. Blow dry and wipe oil over everything that is not painted. I will spend all the next two days finishing the cleaning and making sure guides and lifters fit as they should and check to make sure all is as it should be and then mask for painting. The future owner is a body man and is mixing his own paint and will spray it himself on Wednesday. I think it will be yellow but not sure.

[GOSFAST]

Originally Posted by 4tford

will do, never having a lot of trust in suppliers I took the balanced rotating assembly my buddy purchased on line to my local guy who does a lot of high end racing motors of various breeds. He did the balance all over again. I said Speedway in my original post but only as a reference to what we have. The crank was out a fair bit. He said the rods were bad but the Ross pistons were perfect. This is the block I am using. I am starting to get a routine that works for me. After the block is back from hot tank and magnaflux I do any porting, drill for the adj. lifters and another real good cleaning inside and out. I have a scope to look at the inside of the block. Wash down with "Goof Off" and then Acetone, mask and paint. When the paint is dry I then do another good cleaning and wash with soap and water and then rinse. Blow dry and wipe oil over everything that is not painted. I will spend all the next two days finishing the cleaning and making sure guides and lifters fit as they should and check to make sure all is as it should be and then mask for painting. The future owner is a body man and is mixing his own paint and will spray it himself on Wednesday. I think it will be yellow but not sure.

This is indicative of why we don't buy pre-balanced strokers but choose to put together our own combinations and balance them in-house!

The part about Ross pistons is correct, they are normally the only ones we use, along with the "metric" ring packs.

We use the Eagle shafts because they are easier to balance and we use the Scat rods because they fit the best, least labor intensive, even on the 4.250" strokes!

(Add) I would strongly recommend pressure testing the block, "magging" alone is not a very reliable procedure. There have been issues up here recently that never would have been detected by magnafluxing!!

Thanks, Gary in N.Y.

P.S. It's kind of ironic but I had a long conversation with my friends down at Eagle just 2 days ago, suppied them a photo similar to one below here, and actually (finally) MAY see some design changes to their connecting rods. We shall see in the near future! Explained (again) why we don't use their rods on any builds, they DO NOT fit (without major labor), even on the 4.000" strokes.

[Pete]

By jove myte, don't swim in the billabongs while drinking plonk.

[52merc]

pete a billabong is Australian plonk is a cheap wine mate is aus and kiwi and yes ive had problems while in your great country with people not understanding me plus telling me to slow the speech down so I don't know how any of you guys can understand kiwi in us with a mix of 2 brouges tony is that what you find? trev

[52merc]

bill how does scat balance there rotating assemblys without the front pully flywheel and clutch cover???? it must be a rough balance

[Pete]

Gary,
This an "H" rod just roughed out but you get the idea.
The SCAT's are slightly heavier than the old CAT's as they come but no problem getting them down. The basic quality of the various brands seems to be good.
We have never had one break (knock on wood) and we have several 100% nitro burners using them.

[GOSFAST]

Originally Posted by Pete

Gary,
This an "H" rod just roughed out but you get the idea.
The SCAT's are slightly heavier than the old CAT's as they come but no problem getting them down. The basic quality of the various brands seems to be good.
We have never had one break (knock on wood) and we have several 100% nitro burners using them.

Hi Pete, I hear what you're saying, I'm not sure even with running "nitro" you would make enough power to break these H-beam rods??

As "thin" as the Scat beams are I believe they would be next to impossible to break given the environment??

My discussion with Eagle was an "eye-opener" for them and they often wondered why I wasn't getting the Flathead H-beam rods from them?? I would be getting 4 or 5 cranks at a time but no rods. I brought this to their attention some years ago, but if you can't get past the "buffer-zone" (this is what I call the guys on the order line who do nothing but take the orders) then the people in charge don't get the message.

We cannot sell rods that customers can't fit into the castings without extensive work, not to mention the real risk of grinding the lower bore case to clear the rod beams and hitting water. Basically speaking, you now have 200# of "junk" on your hands because of the rod design!

(Add) Pete, just curious, but do you have those rod weights, total and pin-end, and do you have the beam-width dimensions?? Also, what rod brg do you use??

Thanks, Gary in N.Y.

P.S. The first and ONLY set of Eagle rods for the Flathead I used, about 8 years ago, I ended up actually machining the beams narrower (on one side only) in a fixture on the Bridgeport. That was it for me with the Eagle rods. Now they are "listening", finally. The ironic part is they sell the full Flathead kits as well WITH the Ross pistons, if they'd change the rod dimensions I could pick up the entire kits from them and simply balance them here! It would really make life much easier! The freight saving alone would be "heaven sent"!!

[JWL]

My first disclaimer is that I have never used SCAT rods. However, I have had camshaft interference with STOCK 29A rods and 4 1/4" stroke crank.

In my case the camshaft was done on a new billet so the lobe height was near cam bearing diameter. A reground cam, no matter what the lift is, could have much more clearance. But, the SCAT rods probably take up more space than the stock 29A rods. Bottom line----be very careful as I think the cam to SCAT rod clearance could be minimal.