Ok so here's the deal. I have an Oldsmobile 425 with "A" heads. The whole motor is in stock form. I don't have allot of money. Just wanna get it running good. Didn't even send it to the machine shop. However i did have to buy a new set of hydraulic lifters because the old ones were not working at all. I bought them from Howard's cams (part #: 91411). The only difference i noticed with these lifters after the fact is that the seat height for these new lifters are a little bit lower than the originals which obviously causes the pushrod to sit lower and excessive play in the valve train. And A head Oldsmobile rocker arms are not adjustable at all. They just get torqued down to spec and that's it. Any adjustment must be made in pushrod length. And again i don't have a whole lot of money for a whole new upgraded adjustable valve train. Gotta make do with the least amount possible. I looked for lifters with higher seats couldn't find any. So i emailed Mondello Twister with my exact situation and i asked them how i would use their adjustable pushrod and "checking spring" kit that they sell on their website to get a good accurate measurement for new pushrods. He called me the next day and told me that my best bet is to run the engine with all adjustable pushrods of which i would expand them until it reaches 0 lash and then go another half turn. Which makes sense but i didn't know that you actually can run an engine with adjustable pushrods, i thought they were only for measuring for new ones. He told me they sell a kit of 16 for $299 which i actually don't see on their website. I only see the individual ones. I'm not saying i don't believe him. I'm just an amateur myself so I'm just gathering information trying to find the right answer. But i did see ALOT of threads online about Mondello screwing people in all kinds of ways after the founder of the company Joe no longer ran the company. Other than that one phone conversation I haven't dealt with them in the past. But i will say that they responded promptly. I liked that. Unfortunately i didn't catch what his name was. Or maybe i just forgot shortly after. I didn't know anything about that company until afterwards i did some research. So what do you think? Thanks in advance for any help.
Pushrod length. Should I take advise from Mondello Twister?
- Thread starter Mattyp77
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you can get one of these to check the length..
http://www.jegs.com/i/JEGS-Performance-Products/555/80680/10002/-1
http://www.jegs.com/i/JEGS-Performance-Products/555/80680/10002/-1
Lets start with your 425, there were 2 diffrent size lifter bores olds used on the 425 depending on the car. Toro's used .921-inch and the rest used .842-inch bore. Measure your old lifters O.D. to see what lifter bore you have. I would not use those new lifters if they are shorter somthing not right. I did look up Howards part # 91411 and those lifters can be used in other GM engines, a red flag to me. If you can i would return them. There are a lot of Olds venders out there that will help you to get the lifters you need.
I have issues with the idea that the old lifters were "not working at all"...why were they not working? No oil pressure? flat cam? no pushrods? engine full of water and they were rusted solid?
Need more info, and am also curious why if this is a budget deal you didn't buy OE style replacements from somewhere like rockauto, they list them for 1966 Delta 88 for just over $3 each, marketed by Melling
Need more info, and am also curious why if this is a budget deal you didn't buy OE style replacements from somewhere like rockauto, they list them for 1966 Delta 88 for just over $3 each, marketed by Melling
Don't follow Mondello's advice, period. I know a guy that should have a source for a proper replacement .921" lifter, if that is what you are after. Dave Smith, Rocket Racing, BTR Performance, heck even Dick Miller or Olds Performance Products are better sources for advice and parts. I use Mark Remmel, he does custom cam grinds, EFI and full builds for the Olds V8.
Buick and Olds motors can and do use adjustable pushrods. As do Harley engines and many others. The aftermarket did come up with roller.rocker arms sets that have an adjustable cup for the pushrod for slight changes in length. Seem like Mopar uses a similar set up.
Please confirm you have the correct lifter, also, seems like there was something about lifter/valve angle (39°?) being different on the A head versus all the rest.
Several of my 455 Buicks and two 350 Buicks I have use adjustable pushrods, I don't remember giving $300 for them.
Please confirm you have the correct lifter, also, seems like there was something about lifter/valve angle (39°?) being different on the A head versus all the rest.
Several of my 455 Buicks and two 350 Buicks I have use adjustable pushrods, I don't remember giving $300 for them.
Thanks everybody for the quick response. I think the biggest moral of the story here is get the right lifters then go from there. [84 W40] You made a good point that the lifters I bought are said to not only work with Oldsmobile engines but Pontiac also. In fact I really think that is where the problem really lies. I'm betting that Pontiac lifters are almost exactly the same but have a slightly different seat height.
[Ribbed roof] Sorry I didn't give more detail on that. When i first started working on the motor I noticed that it wasn't getting Any oil to the rockers no matter what i did. But the pushrods we're not clogged at all. Took the lifters out and tried spraying air and carb cleaner through the oil holes. None of them were getting any flow at all. Soaked them in gas for a week and it only made nominal improvement. Tried other things too like marvel mystery and what not. Just wasn't opening up enough. Got the new ones and they worked fine. Oil was getting into the rockers in no time. So that's that. [Olds 307 and 403] . I did check those lifter sizes a while ago and found that they were .841 which is consistent with previous knowledge that it was not out of a Toronado. But thanks for the advise and references. [Bar 50] Really? So you say it is okay to run an engine with adjustable pushrods? A lot of other people seam to be saying no. But regardless I think would be best to look for the exact correct lifters for that engine then go from there. And yes there is some technical differences with 39 and 45 degree cam bank angle blocks. But that one shouldn't Really affect me. That comes into play when swapping cams and heads. To my understanding anyway.
[Ribbed roof] Sorry I didn't give more detail on that. When i first started working on the motor I noticed that it wasn't getting Any oil to the rockers no matter what i did. But the pushrods we're not clogged at all. Took the lifters out and tried spraying air and carb cleaner through the oil holes. None of them were getting any flow at all. Soaked them in gas for a week and it only made nominal improvement. Tried other things too like marvel mystery and what not. Just wasn't opening up enough. Got the new ones and they worked fine. Oil was getting into the rockers in no time. So that's that. [Olds 307 and 403] . I did check those lifter sizes a while ago and found that they were .841 which is consistent with previous knowledge that it was not out of a Toronado. But thanks for the advise and references. [Bar 50] Really? So you say it is okay to run an engine with adjustable pushrods? A lot of other people seam to be saying no. But regardless I think would be best to look for the exact correct lifters for that engine then go from there. And yes there is some technical differences with 39 and 45 degree cam bank angle blocks. But that one shouldn't Really affect me. That comes into play when swapping cams and heads. To my understanding anyway.
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