[grivera]

So this one also has the BBC rod journals. Before I return, are there rod and piston combos available to make this work in a stroked 400 block?

Pics attached. Measurements in 40 degree garage with Harbor Freight dial caliper and depending on positioning the measurements for MJ and RJ's were wither at advertised size or a hair under.

[grivera]

More pics

[grivera]

Last batch

[GoatZillaRacing]

Originally Posted by grivera

Last batch

Check it for straightness. It's really a better deal that they are BBC rod journals because there are many more affordable BBC rods and bearings available.

[mgarblik]

Originally Posted by GoatZillaRacing

Check it for straightness. It's really a better deal that they are BBC rod journals because there are many more affordable BBC rods and bearings available.

Question: Do the Molnar crankshafts have that same , Eagle style"winking eyeball" oil feed holes? That design is just wrong in so many ways. Over 6000 RPM your into cavitation and oil starvation, especially with the Pontiac marginal oil system. I will soon be in the market for a forged crankshaft, but personally won't use one with that style feed. Factory chamfered oil inlets would be better. It must be much less expensive to just hog those big divots into the shaft rather than create a nice smooth scoop. Here are some pics of proper oil inlets.

[Mike Davis]

Originally Posted by grivera

So this one also has the BBC rod journals. Before I return, are there rod and piston combos available to make this work in a stroked 400 block?

Pics attached. Measurements in 40 degree garage with Harbor Freight dial caliper and depending on positioning the measurements for MJ and RJ's were wither at advertised size or a hair under.

There are a lot of piston /rod combos that will work with the 2.200 mains. Depending on budget a set of Scat or Eagle H beams and a Icon or Ross piston would work well.

https://uempistons.com/series-1643-i...7-1-ic937.html

I personally like the 2.200 journal like Randy stated, a lot more choices in bearings and rods.

[grivera]

I assume I have to take it to a machine shop to have a check for straightness?

[Mike Davis]

Originally Posted by grivera

I assume I have to take it to a machine shop to have a check for straightness?

Yes, but that should be done with any crankshaft no matter what brand or material. I have seen factory cranks bent and high dollar cranks bent...…..

[Stan Weiss]

Did I do it wrong for all of those years? I would put a bearing in #1 and #5. Lay crank in and put dial indicator on #3 main and rotate the crank.

Stan

["QUICK-SILVER"]

Originally Posted by mgarblik

Question: Do the Molnar crankshafts have that same , Eagle style"winking eyeball" oil feed holes? That design is just wrong in so many ways. Over 6000 RPM your into cavitation and oil starvation, especially with the Pontiac marginal oil system. I will soon be in the market for a forged crankshaft, but personally won't use one with that style feed. Factory chamfered oil inlets would be better. It must be much less expensive to just hog those big divots into the shaft rather than create a nice smooth scoop. Here are some pics of proper oil inlets.

Mike,
Would 3/4 or full groove mains be enough to overcome that?

Clay

[Mike Davis]

Originally Posted by Stan Weiss

Did I do it wrong for all of those years? I would put a bearing in #1 and #5. Lay crank in and put dial indicator on #3 main and rotate the crank.

Stan

Well that is how I check, but also check journal 2 and 4.

[mgarblik]

Originally Posted by "QUICK-SILVER"

Mike,
Would 3/4 or full groove mains be enough to overcome that?

Clay

I honestly don't know. I just don't like the way those oil hole areas are finished. Personal preference, I guess. At lower engine speeds, they are probably fine. I have seen heavily distressed bearings in Chevy and Pontiac engines that have utilized that style oil passage. If you think about it, bearing support area is taken away from grinding a giant divot across the journal. Then they just polish the surface and call it done. I think much more care and detail needs to go into that area of the engine. Even the factory just drilled the holes, broke the edges and then polished. I have been overall impressed with the Molnar rods and was just curious how they finished their cranks. Interesting side note: I have been all over the internet looking for a single good picture of the oil holes in a Molnar crankshaft. Not a single good picture, including the Molnar website. I will talk to Tom Molnar and look in person at PRI next week. That's the beauty of PRI.

[GoatZillaRacing]

Originally Posted by mgarblik

I honestly don't know. I just don't like the way those oil hole areas are finished. Personal preference, I guess. At lower engine speeds, they are probably fine. I have seen heavily distressed bearings in Chevy and Pontiac engines that have utilized that style oil passage. If you think about it, bearing support area is taken away from grinding a giant divot across the journal. Then they just polish the surface and call it done. I think much more care and detail needs to go into that area of the engine. Even the factory just drilled the holes, broke the edges and then polished. I have been overall impressed with the Molnar rods and was just curious how they finished their cranks. Interesting side note: I have been all over the internet looking for a single good picture of the oil holes in a Molnar crankshaft. Not a single good picture, including the Molnar website. I will talk to Tom Molnar and look in person at PRI next week. That's the beauty of PRI.

Here you go! Molnar Crank

["QUICK-SILVER"]

Originally Posted by "QUICK-SILVER"

Mike,
Would 3/4 or full groove mains be enough to overcome that?

Clay

Got confused there after looking at Mike's pics. Got pics mixed up between the rod journal pic and main pic.

So what do the feed holes in the mains look like on the OP's crank?

Clay

[GoatZillaRacing]

Originally Posted by "QUICK-SILVER"

Got confused there after looking at Mike's pics. Got pics mixed up between the rod journal pic and main pic.

So what do the feed holes in the mains look like on the OP's crank?

Clay

The Speedmaster cranks have a small divot on both sides of the main feed hole like you ground it with a bit or cartridge roll across the hole. Very old school but not unrepairable.

[Hooter]

My 4.375 Molnar crank was like the pics Randy posted.

[grivera]

Originally Posted by Mike Davis

Yes, but that should be done with any crankshaft no matter what brand or material. I have seen factory cranks bent and high dollar cranks bent...…..

If bent, is a machine shop able to straighten?

[Mike Davis]

Originally Posted by grivera

If bent, is a machine shop able to straighten?

It can be done if they are a good shop.
I would not sweat it right now until you have it checked. The oil holes are minor and unless it is a max effort it won't matter. I have a crank that the oil holes look like that that was run for years at over 7K RPM. Just put a good oil pump in it and watch the clearances.

[mgarblik]

Originally Posted by GoatZillaRacing

Here you go! Molnar Crank

Thank you for the pics of the Molnar crank. It's lovely IMO. If I was buying a forged crank, that oil feed design and finish is what I would be looking for in a higher RPM component. I know the Molnar cranks are off shore like all the others, but that piece is clearly a nicer, more finished piece than anything I have seen from Eagle, Ohio Crankshaft and some of the other vendors. Look forward to talking to Tom at PRI. My next personal build will be a mild solid roller cam engine that I want to feel safe shifting at 7000-7500 RPM. So a good oiling system and delivery to the bearings is important.