Just got a 01 Lude for about a month now. Brought it from a mechanic which he got from one of his customer. He swapped the prelude block with a 2.3 liter F23 block (from an accord I believe) with the same H22 cylinder head. The only thing that's weird is he told me to use 20-50 nonsynthetic engine oil, is there any good reason to why he want the lude to run on an oil that hasn't been used a lot since the 70s???
I got the car from Texas and the car has been there its entire life. I live in Florida so low-temp is never going to be a problem. I have an oil pan gasket leak so I want to see if I need to continue with 20-50 or the Honda recommended 5w30 before I fix the gasket and put in new oil.

P.S. The only modified parts on the lude are the intake and the block, everything else is OEM. The original owner owned it from 2001 to at least 2019 (maybe longer but service maintenances paper I got stops at 2019) So overall I think the car is in great condition but I just don't understand why he wants me to use 20-50.

 

pretty sure original spec oil for both the H22 and F23 in that year range is 5w20. use that. the only time I would suggest considering non-OE weight oil is

A- you're in a situation where you need to chose between the "wrong" oil or not enough oil. choose having enough.
B- you have had the oil analyzed by professionals like Blackstone Labs and they recommend a different weight based on the results.
B2- you work in an industry where you regularly deal with spec-ing or designing specs for lubricants, perhaps a lubricants application engineer.

 

Thank you for ur input man! I definitely want to switch the oil from 20-50 to something. Do you have any recommendations between 5w20 vs 5w30? Especially in Florida weather. My car has 120,000 miles but only around 3000 miles after the F23 block, but everything else are from H22 so mostly everything has 120k wear on it.

 

5w20 is too thin for a H22... I would use the recommended 5w30. If aftermarket bearings were installed into the F23 shortblock, oil clearances may be larger than the original specs, and in this case, thicker oils must be used to maintain proper function. To test this theory, fill with 5w30 and test drive the vehicle. If VTEC functions normally, I would suggest you continue to use this engine oil viscosity. If VTEC fails or clicks in and out... a thicker oil will need to be used.