TR230 cam, what valve springs?
09-12-2009, 11:52 PM
#1
TR230 cam, what valve springs? I talked to Thunder Racing since they made the cam and they said Comp 918 springs. The heads I am putting on have Comp 977's on it now. Thunder Racing said if the 977's are installed at 1.850 they would work but the guy said the 918's would be better.
I am using Harland Sharp aftermarket roller rockers, not the upgraded stock pieces. I didn't know if these rockers are heavier and will effect what spring I should get.
Also do the 977's and the 918's use the same retainers?
Thank you.
Jason
I am using Harland Sharp aftermarket roller rockers, not the upgraded stock pieces. I didn't know if these rockers are heavier and will effect what spring I should get.
Also do the 977's and the 918's use the same retainers?
Thank you.
Jason
09-14-2009, 12:57 AM
#6
I have read there was a problem with 918's in the past but I "think" Comp fixed the issue.
I thought about the Patriot dual golds too. I don't know anything about the PAC 1518's.
If I read correctly the 977's have a larger outer diameter than the 918's. Do the 977's require machine work do the heads? If so would the 918's "walk" around any if the head was machined larger?
I thought about the Patriot dual golds too. I don't know anything about the PAC 1518's.
If I read correctly the 977's have a larger outer diameter than the 918's. Do the 977's require machine work do the heads? If so would the 918's "walk" around any if the head was machined larger?
03-09-2010, 01:25 AM
#14
I bring this question back up. I called Thunder Racing but haven't heard back from them. This is my question.
The 1218's are rated to .600 lift and the open pressure is 318
The 1518's are rated to .650 lift and the open pressure is 337
The 918's are rated to .600(i think) and the open pressure is 367.
That is a big difference from the 918's and the 1518 and an even bigger difference to the 1218's. I have read that excessive spring pressure can add to accelerated wear and loss of HP but to light of spring pressure will result in valve float. Since I have around .570 lift I thought the 1218's would be OK because I didn't need the .650 lift the 1518 provided but then I started thinking about spring pressure and float. I would rather stay with a single spring because of the weight/mass.
I am waiting to hear back from Thunder and I will do whatever they tell me to. I am bored and wanted some feedback. I will post back after I talk to them.
Thank you.
The 1218's are rated to .600 lift and the open pressure is 318
The 1518's are rated to .650 lift and the open pressure is 337
The 918's are rated to .600(i think) and the open pressure is 367.
That is a big difference from the 918's and the 1518 and an even bigger difference to the 1218's. I have read that excessive spring pressure can add to accelerated wear and loss of HP but to light of spring pressure will result in valve float. Since I have around .570 lift I thought the 1218's would be OK because I didn't need the .650 lift the 1518 provided but then I started thinking about spring pressure and float. I would rather stay with a single spring because of the weight/mass.
I am waiting to hear back from Thunder and I will do whatever they tell me to. I am bored and wanted some feedback. I will post back after I talk to them.
Thank you.
03-09-2010, 01:31 AM
#15
Yeah, you unearthed this bad boy. Must have been 20 pages or more deep. for a .570 lift cam all you need is a single spring. I havent heard anything bad about the 918's in a few years. I always ran them. Also, I havent heard anything but good stuff on the PAC 12's and 15's. It will probably just come down to which is a better deal.
03-10-2010, 02:46 PM
#18
I spoke with TR today. They said they normally use a 981 spring. I think I got that confused before and thought the 918.
The 981 has 110 closed/292 open pressure so the 1218's I ordered should be about perfect and not have excessive pressure.
The 981 has 110 closed/292 open pressure so the 1218's I ordered should be about perfect and not have excessive pressure.
